Atlas of Airway Management - Techniques and Tools (PDFDrive)

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Atlas of
Airway Management:
Techniques and Tools
2nd Edition
Steven L. Orebaugh, MD
Associate Professor of Anesthesiology and Critical Care Medicine
University of Pittsburgh School of Medicine
UPMC Southside/Mercy Amulatory Center
Pittsburgh, Pennsylvania
Paul E. Bigeleisen, MD
Professor of Anesthesiology
University of Pittsburgh School of Medicine
Pittsburgh, Pennsylvania
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Library of Congress Cataloging-in-Publication Data
Orebaugh, Steven L.
Atlas of airway management : techniques and tools / Steven L. Orebaugh. — 2nd ed.
p. cm.
ISBN 978-1-4511-0339-7
ISBN 1-4511-0339-5
1. Airway (Medicine)—Atlases. 2. Trachea—Intubation—Atlases. 3. Artificial respiration—Atlases. I. Title.
RC732.O74 2012
616.2' 3—dc23
2011022795
First Edition ©2007 by Lippincott Williams & Wilkins
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remains the professional responsibility of the practitioner.
The authors, editors, and publisher have exerted every effort to ensure that drug selection and dosage set forth in
this text are in accordance with current recommendations and practice at the time of publication. However, in view of
ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and
drug reactions, the reader is urged to check the package insert for each drug for any change in indications and dosage
and for added warnings and precautions. This is particularly important when the recommended agent is a
new or infrequently employed drug.
Some drugs and medical devices presented in the publication have Food and Drug Administration (FDA) clearance for
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Dedication
We dedicate this atlas to the anesthesiology residents, anesthesiologists and other

acute care physicians who provide life-saving airway management to the patients
at the University of Pittsburgh Medical Center hospitals.
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Contributors List
Ali R Abdullah, MBChB Franklyn Cladis MD

Resident Physician, Department of Anesthesiology, Assistant Professor, Department of Anesthesiology, The
University of Pittsburgh School of Medicine, Pittsburgh, University of Pittsburgh School of Medicine, Children’s
Pennsylvania Hospital of Pittsburgh of UPMC, Pittsburgh Pennsylvania
Mark Backeris, DO Ivan Colaizzi, MD

Resident Physician, Department of Anesthesiology, Clinical Assistant Professor, Department of Anesthesiology,
University of Pittsburgh School of Medicine, Pittsburgh, Univeristy of Pittsburgh School of Medicine, Pittsburgh,
Pennsylvania Pennsylvania
Joshua Baisden, MD Christopher W. Connor, MD, PhD

Department of Anesthesiology, University of Pittsburgh Assistant Professor of Anesthesiology and Biomedical
Medical Center, Pittsburgh, Pennsylvania Engineering, Boston University, Boston, Massachusetts
Ryan D. Ball, MD Daniel Cormican, MD

Chief Anesthesiology Resident, Department of Resident Physician, Department of Anesthesiology,
Anesthesiology, University of Pittsburgh Medical Center, University of Pittsburgh School of Medicine, Pittsburgh,
Pittsburgh, Pennsylvania Pennsylvania
Shawn T. Beaman, MD David Crippen, MD, FCCM

Assistant Professor, Associate Residency Program Director, Professor, Department of Critical Care Medicine, University
Department of Anesthesiology, University of Pittsburgh of Pittsburgh Medical Center, Pittsburgh, PA
School of Medicine, Pittsburgh, Pennsylvania
Patricia Dalby, MD
Nikhil Bhatnagar MD Assistant Professor, Department of Anesthesiology,
Resident Physician, Department of Anesthesiology, University of Pittsburgh School of Medicine,
University of Pittsburgh Medical Center, Pittsburgh, Anesthesiologist, Department of Anesthesiology,
Pennsylvania Magee-Women’s Hospital, Pittsburgh, Pennsylvania
Brian Blasiole, MD, PhD James Dargin, MD

Fellow, Pediatric Anesthesiology, Department of Intensivist, Department of Pulmonary and Critical Care
Anesthesiology, University of Pittsburgh Medical Center, Medicine, Lahey Clinic, Burlington, Massachusetts
Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania
Derek Davis, MD
Lawrence M. Borland, MD Assistant Professor, Department of Anesthesiology,
Associate Professor, Department of Anesthesiology, University of Pittsburgh Medical Center, Pittsburgh,
University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
Pennsylvania
William B. Ehrman, DO
Adam P. Childers, MD Resident Physician, Department of Anesthesiology,
Resident, Department of Anesthesiology, University of University of Pittsburgh Medical Center, Pittsburgh,
Pittsburgh Medical Center, Pittsburgh, Pennsylvania Pennsylvania
iv
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CONTRIBUTORS LIST v
Lillian L. Emlet, MD, MS, FACEP Arun L. Jayaraman, MD, PhD

Assistant Professor, Department of Critical Care Medicine Resident Physician, Department of Anesthesiology,
and Emergency Medicine, University of Pittsburgh Medical University of Pittsburgh School of Medicine, Pittsburgh,
Center, Pittsburgh, PA Pennsylvania
CA-2 Resident, Department of Anesthesiology, University of
Stephen Esper, MD Pittsburgh Medical Center
Resident, Department of Anesthesiology, University of
Pittsburgh Medical Center, Pittsburgh, Pennsylvania A. Murat Kaynar, MD, MPH
Attending Physician, (Assistant Professor), Department of
Peter F. Ferson, MD Critical Care Medicine and Department of Anesthesiology,
Professor of Surgery, Department of Cardiothoracic University of Pittsburgh School of Medicine, Pittsburgh,
Surgery, University of Pittsburgh School of Medicine, Pennsylvania
Staff Surgeon UPMC Presbyterian and VA Health System,
Pittsburgh Miroslav Klain, MD, PhD
Professor Emeritus, Department of Anesthesiology,
Patrick Forte, MD University of Pittsburgh Medical School, Attending
Assistant Professor, Department of Anesthesiology, University Physician, Department of Anesthesiology, Presbyterian
of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania University Hospital, Pittsburgh, Pennsylvania
Theresa Gelzinis, MD Tara Knizner, MD

Assistant Professor, Associate Professor of Anesthesiology, Resident, Department of Anesthesiology,
University of Pittsburgh School of Medicine, Pittsburgh, PA University of Pittsburgh Medical Center, Pittsburgh,
Staff Anesthesiologist, University of Pittsburgh Medical Pennsylvania
Center-Oakland
Robert Scott Lang, MD
Brian Gierl, MD Resident, Department of Anesthesiology,
Resident Physician, Department of Anesthesiology, University of Pittsburgh Medical Center, Pittsburgh,
University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
Pennsylvania
Kristin Ondecko Ligda, MD
Joseph S. Goode, Jr., CRNA, MSN Resident Physician, Department of Anesthesiology,
Faculty, University of Pittsburgh School of Nursing, Nurse University of Pittsburgh, Pittsburgh, Pennsylvania
Anesthesia Program Staff Nurse Anesthetist
UPMC-Presbyterian, Pittsburgh, PA Charles Lin, MD
Attending Anesthesiologist, Department of Anesthesiology,
Kevin M. Hibbard, MD University of Pittsburgh Medical Center, Pittsburgh,
Resident, Department of Anesthesiology, University of Pennsylvania
Pittsburgh, University of Pittsburgh Medical Center,
Pittsburgh, Pennsylvania Mark I. Lischner, DO
Resident, Department of Anesthesiology, University of
Ibtesam Hilmi, MB CHB, FRCA Pittsburgh Medical Center, Pittsburgh, Pennsylvania
Associate Professor, Department of Anesthesiology,
Associate Professor, Clinical and Translational Science Matthew JP LoDico, MD
Institute, University of Pittsburgh, Director of Quality Resident Physician, Department of Anesthesiology,
Assurance UPMC-Presbyterian Hospital University of Pittsburgh School of Medicine, Pittsburgh,
Pennsylvania
Bo Hu, PhD
Department of Anesthesiology, University of Rochester Michael Mangione MD
School of Medicine and Dentistry and Center for Visual Associate Professor of Anesthesiology, University of
Science, University of Rochester, Rochester, New York Pittsburgh School of Medicine, Chief of Anesthesiology, VA
Pittsburgh Healthcare System
Dustin J. Jackson, MD
Resident, Department of Anesthesiology, Unviersity of Ana Manrique, MD
Pittsburgh School of Medicine, University of Pittsburgh Resident, Department of Anesthesiology, University of
Medical Center, Pittsburgh, Pennsylvania Pittsburgh Medical Center, Pittsburgh, Pennsylvania
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vi CONTRIBUTORS LIST
Stephen M. McHugh, MD Katherin A. Peperzak, MD

Resident, Department of Anesthesiology, University of Resident, Department of Anesthesiology, University of
Pittsburgh Medical Center, University of Pittsburgh Medical Pittsburgh Medical Center, Pittsburgh,
Center, Pittsburgh, Pennsylvania Pennsylvania
William R. McIvor, MD Paul E. Phrampus, MD

Associate Professor, Department of Anesthesiology, Associate Professor, Departments of Emergency Medicine
University of Pittsburgh School of Medicine, Pittsburgh, and Anesthesiology, Vice Chair, Quality and Patient Safety,
Pennsylvania Department of Emergency Medicine, Director, Peter M
Winter Institute for Simulation, Education and Research
Samer Melhem, MD (WISER), University of Pittsburgh and UPMC, Pittsburgh,
Resident Physician, Department of Anesthesiology, Pennsylvania
University of Pittsburgh School of Medicine, Pittsburgh,
Pennsylvania
Raymond M. Planinsic, MD
David G. Metro, MD Associate Professor of Anesthesiology, University of
Assistant Professor, Associate Professor of Anesthesiology, Pittsburgh School of Medicine, Director of Transplantation
University of Pittsburgh School of Medicine, Pittsburgh, PA Anesthesiology, University of Pittsburgh Medical Center,
Staff Anesthesiologist, University of Pittsburgh Medical Pittsburgh, Pennsylvania
Center-Oakland
Joseph J. Quinlan, MD
Mario Montoya, MD Professor of Anesthesiology, Department of Anesthesiology,
Visiting Assistant Professor, Department of Anesthesiology, University of Pittsburgh, Chief Anesthesiologist, Department
University of Pittsburgh Medical Center, Pittsburgh, of Anesthesiology, University of Pittsburgh Medical
Pennsylvania Center - Presbyterian, Pittsburgh, Pennsylvania
Scott K. Muir, DO Max E. Rohrbaugh, MD

Resident Physician, Department of Anesthesiology, Resident, Department of Anesthesiology, University of
University of Pittsburgh, University of Pittsburgh Medical Pittsburgh, Pittsburgh, Pennsylvania
Center, Pittsburgh, Pennsylvania
Adam Munson-Young, MD Ryan C. Romeo, MD

Resident, Department of Anesthesiology, University of Associate Professor of Anesthesiology, University of
Pittsburgh Medical Center, Pittsburgh, Pennsylvania Pittsburgh School of Medicine, Pittsburgh, PA
Andrew Murray MB ChB Tetsuro Sakai, MD, PhD

Assistant Professor, Department of Anesthesiology, Associate Professor, Department of Anesthesiology,
University of Pittsburgh School of Medicine, Pittsburgh, University of Pittsburgh School of Medicine, Pittsburgh,
Pennsylvania Pennsylvania; Faculty Member, The McGowan Institute for
Regenerative Medicine, University of Pittsburgh, Pittsburgh,
Spencer G. Nabors, MD, MPH, MA Pennsylvania
Postdoctoral Scholar, Clinical Instructor, Department of Critical
Care Medicine, University of Pittsburgh Medical Center Kristin Schreiber, MD/PhD
Resident Physician, Department of Anesthesiology,
Todd Oravitz, MD University of Pittsburgh School of Medicine, Pittsburgh,
Associate Professor, Department of Anesthesiology, Pennsylvania
Pennsylvania
Scott Segal, MD, MHCM
Sarah Parker, MD Professor and Chair, Department of Anesthesiology, Tufts
Resident, University of Pittsburgh School of Medicine, University School of Medicine, Boston, Massachusetts
Department of Emergency Medicine
Pranav R. Shah, MD
Nimitt J. Patel, MD Resident Physician, Department of Anesthesiology,
Fellow, Surgical Critical Care, Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh,
University of Pittsburgh, Pittsburgh, Pennsylvania Pennsylvania
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CONTRIBUTORS LIST vii
Anthony Silipo, DO PGY-4 Samuel A. Tisherman, MD

Chief Resident Physician, Department of Anesthesiology, Professor, Departments of Critical Care Medicine and
University of Pittsburgh School of Medicine, Pittsburgh, Surgery, University of Pittsburgh, Pittsburgh, PA
Pennsylvania
Jay B. Tuchman MD, FAAP
Elizabeth H. Sinz, MD Assistant Professor, Department of Anesthesiology,
Professor, Department of Anesthesiology & Neurosurgery, University of Pittsburgh School of Medicine, Pittsburgh,
Director, Penn State Hershey Clinical Simulation Center, Pennsylvania
Office of Education Affairs, Penn State Hershey Medical
Center, Hershey, Pennsylvania Manuel C. Vallejo, MD, DMD
Professor, Department of Anesthesiology, University of
James V. Snyder, MD Pittsburgh, Director, Obstetric Anesthesia, Department
Professor Emeritus, Critical Care Medicine, University of of Anesthesiology, Magee-Womens Hospital of UPMC,
Pittsburgh Medical Center Pittsburgh, Pennsylvania
Audra Webber, MD
Erin A. Sullivan, MD
Resident Physician, Department of Anesthesiology,
Associate Professor of Anesthesiology, Director Division
of Cardiothoracic Anesthesiology, University of Pittsburgh
Pennsylvania
Physicians Department of Anesthesiology, Pittsburgh,
Pennsylvania
Cynthia Wells, MD
Assistant Professor of Anaesthesiology, University
Kathirvel Subramaniam, MD of Pittsburgh School of Medicine, Department of
Clinical Assistant Professor, Department of Anesthesiology, Anesthesiology, Staff Anesthesiologist UPMC-Presbyterian,
University of Pittsburgh School of Medicine, Pittsburgh, Pittsburgh, PA
Pennsylvania
Ryan R. Wilson, MD
Joseph F. Talarico, DO Resident Physician, Department of Anesthesiology,
Associate Professor of Anesthesiology, University of University of Pittsburgh School of Medicine, Pittsburgh,
Pittsburgh School of Medicine, Pittsburgh, PA Pennsylvania Ryan R. Wilson, MD PGY-3 Department of
Anesthesiology University of Pittsburgh Medical Center
Paul G. Tarasi, MD
Resident Physician, Department of Anesthesiology, Jacek Wojtczak, MD, PhD
University of Pittsburgh School of Medicine, Department of Anesthesiology, University of Rochester
University of Pittsburgh Medical Center, Pittsburgh, School of Medicine and Dentistry and Center for Visual
Pennsylvania Science, University of Rochester, Rochester, New York
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Preface to the Second Edition
I n this, the second edition of the atlas, a number of

changes will be evident. Most importantly, each chapter
is now written by a separate set of authors, rather than
situations, diagnostic and therapeutic bronchoscopy, and
management issues for the post-intubation phase of care.
In order to broaden the appeal of the book for non-
the entire book resulting from the efforts of one individ- anesthesia providers, and in recognition of the frequency
ual, in order to take advantage of the variable experiences of emergent airway management outside of the operat-
and expertise of many different practitioners. In addition ing room, the authors of the chapters are comprised of
to updates and revisions of existing chapters, many new a diverse group of practitioners, including anesthesiolo-
chapters have been added to improve the scope and per- gists (adult and pediatric), intensivists, emergency medi-
spective of the atlas, while describing innovative new tools cine physicians and trauma surgeons. One section of the
which have been added to the clinician’s armamentarium. book includes chapters from critical care physicians and
Examples of specific implements that are now dis- emergency medicine practitioners, describing the unique
cussed in this edition include the Airtraq (chapter 16), a and challenging aspects of airway management that such
prism- and mirror-based device to improve visualization physicians routinely face in the non-operating room
of the larynx, and the video-laryngoscopes recently re- environment.
leased by several manufacturers, which have been rapidly Finally, it must be recognized that direct laryngos-
and successfully adopted to cope with difficult anatomic copy remains the first management choice for acute care
characteristics (chapter 24). Several chapters are now physicians in most situations, for patients requiring intra-
included which describe unique and thought-provoking operative care or emergent airway interventions for other
methods for evaluating a patient’s physical characteristics reasons. Accordingly, the chapters from the prior edition
to help predict the likelihood of difficult laryngoscopy and which deal with airway anatomy, direct laryngoscopy and
intubation. In addition, a chapter has been added to de- the teaching of laryngoscopy to trainees, have been ex-
scribe the nature and utility of non-invasive ventilation, panded in scope, and re-focused in order to provide better
which may reduce morbidity in certain categories of pa- background and instruction for more challenging cases.
tients suffering from respiratory compromise (chapter 3). These now contain suggestions for improved patient po-
High frequency jet ventilation, a modality which may be sitioning, use of assistants to help lift the head and avoid
of use in a number of different operative and critical care operator fatigue, and external manipulation of the larynx
settings, is now considered as well (chapter 48). in a “two-handed” laryngoscopy technique, all of which
Entire new sections have been added to this book, aid in reducing the difficulty of exposing the glottis and
in order to provide coverage of topics which were not effectively placing the endotracheal tube in the airway.
considered, or which were described only briefly, in the
first edition. These include pediatric airway manage- The editors:
ment, preexisting pathology in patients which requires Steven L. Orebaugh
special attention to airway management, specific surgical Paul E. Bigeleisen
viii
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Preface to the First Edition
M y aim in creating this book is to assist those learning

to manage the airway to understand the basics—
mask ventilation and optimal direct laryngoscopy—as
ventilation, direct laryngoscopy, and pharmacology rel-
evant to endotracheal intubation. While the purpose of
this book is to provide information on management of the
well as to comprehend alternative techniques for situ- adult airway, a chapter on the pediatric airway is included.
ations in which direct laryngoscopy is difficult, or can- When applicable, references to pediatric airway manage-
not be utilized. There is an ever-expanding array of air- ment are made in the various chapters covering imple-
way tools, of many different types, covering a spectrum ments or techniques. In the second section, difficult airway
of costs and degrees of complexity. It behooves the pro- management is explored, including the epidemiology of
vider to understand how different techniques work and this life-threatening problem in elective cases in operating
when they are effective so that two or three alternatives room, and in more emergent settings. Decision-making in
to laryngoscopy can be chosen, learned, and practiced. the face of recognized or potential difficult airways, due
Because I initially trained in emergency medicine, then to anatomy, disease, or obesity, for example, is discussed,
critical care medicine and, finally, anesthesiology, I have as well as training of physicians, students, and nurses at
experienced airway management from several different the University of Pittsburgh utilizing high fidelity human
viewpoints. I have attempted to share these perspectives simulation. In the last chapter of this section, a survey of
in this atlas. anatomic and pathologic causes of difficult airway man-
Many fine airway management books exist, rang- agement is presented.
ing from small handbooks to expansive texts. Some of Brevity and an organized format for the text are as im-
these texts suffer from a lack of instructive illustration. portant in an atlas as are the illustrations themselves. For
In an attempt to complement them, this atlas was created, this reason, the chapters covering specific tools or tech-
and thus provides more illustration than text. In order niques are arranged according to the following template:
to make the relationships between anatomy and airway The concept is presented, followed by a discussion of
management tools clear, a large variety of illustrations is existing evidence supporting the use of the intervention.
presented, including mockups in cadaver specimens, pho- Next, the preparatory steps for the procedure are listed,
tos of airway management in the clinical setting, simu- followed by a description of the steps necessary to carry
lated airway management scenarios, and photographs of out the procedure itself. Following this is a listing of ele-
the airway utilizing video laryngoscopes and fiberoptic ments of practicality, affordability, portability, familiarity,
bronchoscopes. complexity, and other concerns which impact the ability
Most of the atlas is dedicated to defining and illustrat- to integrate the tool or technique into medical practice.
ing the many devices and techniques that exist for endo- Finally, indications, contraindications, and complications
tracheal intubation when direct laryngoscopy is difficult of the intervention are noted. A series of illustrations is
or undesirable. These topics are covered in eight parts, in provided, showing the tool(s) involved, how these are
the following areas: adjuncts to direct laryngoscopy, blind placed in the patient (demonstrated in a cadaver speci-
intubation techniques, light-guided intubation, retrograde men), and clinical photos, or simulations, of the device
intubation, fiberoptic techniques, emergency ventilation in use. When appropriate, step-by-step sequential illustra-
techniques (supraglottic and infraglottic), combinations tions show the progression of the procedure.
of techniques, and emergency surgical airways. Within
each section are one to five chapters detailing the devices Steven L. Orebaugh, MD
or procedures that fall under that heading. Assistant Professor of Anesthesiology
The first portion of this atlas is intended to cover basic Assistant Clinical Professor of Emergency Medicine
airway management, including airway anatomy, bag-mask University of Pittsburgh Medical Center, Southside
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Acknowledgments
W e greatly acknowledge the help of Dr. Branton

Barstetter, of the University of Pittsburgh Medical
Center Department of Radiology, for providing the radiologic
nurse anesthetists of the University of Pittsburgh Medical
Center-Southside who enthusiastically assisted in prepara-
tion of photographs for this book, the anesthesiology resi-
images in Chapter 15; Alison Yeung, DDS, and Dr. William dents and medical students from the University of Pittsburgh
Chung of the Oromaxillofacial Surgery Division of UPMC who likewise facilitated the process of obtaining clinical
for photos of oral pathology in Chapter 15; and Samuel photographs and photos of simulated airway management
Tisherman, MD, of the Department of Surgery at UPMC for scenarios, and John McCaulley, medical photographer, who
photos of surgical airway in Chapter 36. Also, we wish to provided much of his time and effort to help bring this idea
thank Stephen Schiller and Karl Storz, Endoscopy, Inc., for to fruition. In addition, we extend sincere appreciation to
generously providing video and digital imaging equipment, our chief editor, Nicole Dernoski, for her professionalism
fiberoptic brochoscopes, and video laryngoscopes. Thanks and patient guidance. Finally, we are most grateful to our
also TO LMA of North America, Mercury Medical, King many co-authors, whose efforts have resulted in a practi-
Medical, Tyco Healthcare, Engineered Medical Systems, and cal and visually appealing manual for instruction of airway
Achi medical products for providing high quality images of management.
their products. We must recognize the anesthesiologists and
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Table of Contents
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Contributors List iv 12 Decision Making in Difficult Airway

Preface to the Second Edition viii Management . . . . . . . . . . . . . . . . . . . . . 87
Preface to the First Edition ix
Acknowledgments x 13 Training in Airway Management:
Difficult Airway Simulation . . . . . . . . . . . . 96
14 Training in Airway Management . . . . . . . . . 103
PART I
15 Examples and Illustrations of
Routine Airway Management . . . . . . . 1 Conditions Predisposing to
Difficult Airway Management . . . . . . . . . . . 109
1 Anatomy of Direct Laryngoscopy . . . . . . . . . . 1
22 Mask Ventilation . . . . . . . . . . . . . . . . . . 13
PART III
3 Noninvasive Ventilation . . . . . . . . . . . . . . 21
4 Retraction Blades Adjuncts to Direct
for Direct Laryngoscopy . . . . . . . . . . . . . . 29 Laryngoscopy . . . . . . . . . . . . . . . . . . . . . 127
5 Direct Laryngoscopy . . . . . . . . . . . . . . . . 35 16 Mirror Blades and Prism Blades . . . . . . . . . . 127
6 Confirmation of Endotracheal
17 Bougies and Airway Stylets. . . . . . . . . . . . . 133
Tube Placement . . . . . . . . . . . . . . . . . . . 45
7 Pharmacology for Airway
Management . . . . . . . . . . . . . . . . . . . . . 50 PART IV
8 Regional Anesthesia Blocks Blind Intubation. . . . . . . . . . . . . . . . . . . 139
for Awake Intubation . . . . . . . . . . . . . . . . 55
18 Blind Nasotracheal Intubation . . . . . . . . . . . 139
PART II 19 Blind Orotracheal Intubation . . . . . . . . . . . 145
Difficult Airway Management:
Recognition, Training and PART V
Management . . . . . . . . . . . . . . . . . . . . . . 61 Lightwands and Optical Stylets . . . . 151
99 Definition, Incidence, and Predictors
20 Lightwands . . . . . . . . . . . . . . . . . . . . . 151
of the Difficult Airway . . . . . . . . . . . . . . . 61
10 Computerized Analysis to 21 Optical Stylets . . . . . . . . . . . . . . . . . . . . 161
Associate Facial Features with Difficult
Intubation . . . . . . . . . . . . . . . . . . . . . . 70
PART VI
11 New Methods of Bedside Airway
Assessment: Cone Beam Computed Retrograde Techniques . . . . . . . . . . . . 167
Tomography, Ultrasound, and
Craniofacial Phenotyping . . . . . . . . . . . . . 76 22 Retrograde Intubation . . . . . . . . . . . . . . . 167
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xii TABLE OF CONTENTS
PART VII 38 Tracheostomy . . . . . . . . . . . . . . . . . . . . 277
Fiberoptic Techniques . . . . . . . . . . . . . 177 39 Percutaneous Tracheostomy . . . . . . . . . . . . 283
23 Flexible Fiberoptic Bronchoscope

Intubation . . . . . . . . . . . . . . . . . . . . . . 177 PART XI
24 Rigid Fiberoptic Scopes and Video Pediatrics . . . . . . . . . . . . . . . . . . . . . . . . . 291
Laryngoscopes . . . . . . . . . . . . . . . . . . . . 191
40 Pediatric Airway Anatomy and
PART VIII Approach. . . . . . . . . . . . . . . . . . . . . . . 291
41 Direct Laryngoscopy in Pediatrics . . . . . . . . . 298
Emergency Ventilation . . . . . . . . . . . . 199
42 Adjuncts to Direct Laryngoscopy
25 Esophageal-Tracheal Combitube . . . . . . . . . 199 in Pediatrics . . . . . . . . . . . . . . . . . . . . . 303
26 Laryngeal Mask Airway. . . . . . . . . . . . . . . 204
27 Intubating Laryngeal Mask Airway . . . . . . . . 214 PART XII
28 Other Supraglottic Airway Devices . . . . . . . . 225
Bronchoscopy . . . . . . . . . . . . . . . . . . . . . 309
29 Transtracheal Jet Ventilation. . . . . . . . . . . . 231
43 Rigid Bronchoscopy. . . . . . . . . . . . . . . . . 309
PART IX 44 Diagnostic and Therapeutic Fiberoptic
Bronchoscopy . . . . . . . . . . . . . . . . . . . . 315
Combination Techniques . . . . . . . . . . 239
30 Intubation through Laryngeal Mask
Airway or Intubation Laryngeal Mask PART XIII
Airway with a Bougie, Lighted Stylet,
or Optical Stylet . . . . . . . . . . . . . . . . . . . 239 Surgical Situations Requiring
Specialized Airway
31 Retrograde Intubation and Flexible
Fiberoptic Bronchoscope Intubation . . . . . . . 243 Management . . . . . . . . . . . . . . . . . . . . . 321
32 Flexible Fiberoptic Bronchoscope Intubation 45 Double-Lumen Endotracheal Tubes. . . . . . . . 321
through the Laryngeal Mask Airway . . . . . . . 247
46 Bronchial Blockers in Thoracic Surgery. . . . . . 328
33 Flexible Fiberoptic Bronchosope
Intubation through the Intubating 47 Laser Airway Surgery . . . . . . . . . . . . . . . . 333
Laryngeal Mask Airway. . . . . . . . . . . . . . . 252
48 High-Frequency Jet Ventilation . . . . . . . . . . 340
34 Flexible Fiberoptic Bronchoscope
Intubation and the Esophago-Tracheal
Combitube . . . . . . . . . . . . . . . . . . . . . . 257 PART XIV
35 Transtracheal Jet Ventilation and Flexible
Fiberoptic Bronchoscope Intubation . . . . . . . 260 Unique Facets of Airway
Management by
Discipline . . . . . . . . . . . . . . . . . . . . . . . . . 351
PART X
Emergency Surgical Airways . . . . . . 265 49 Airway Management in Critical
Care Medicine . . . . . . . . . . . . . . . . . . . . 351
36 Cricothyrotomy . . . . . . . . . . . . . . . . . . . 265
50 Airway Management in Emergency
37 Wire-Guided Cricothyrotomy . . . . . . . . . . . 273 Medicine . . . . . . . . . . . . . . . . . . . . . . . 357
DESIGN SERVICES OF
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TABLE OF CONTENTS xiii
PART XV PART XVI

Common Patient Conditions Care After Intubation . . . . . . . . . . . . . 379
Requiring Specialized Approach
54 Positive Pressure Ventilation. . . . . . . . . . . . 379
to the Airway . . . . . . . . . . . . . . . . . . . . . 361
55 Complications of Intubation:
51 Obstructive Sleep Apnea Acute and Chronic . . . . . . . . . . . . . . . . . 394
and Airway Management . . . . . . . . . . . . . . 361 56 Care of the Patient with a Surgical Airway: An
52 Morbid Obesity and Bariatric Surgery. . . . . . . 370 Approach to Emergency Interventions . . . . . . 403
53 Obstetrics . . . . . . . . . . . . . . . . . . . . . . 375 Index 408
DESIGN SERVICES OF
Orebaugh_FM.indd xiii 18/07/11 7:50 PM

Orebaugh_FM.indd xiv 18/07/11 7:50 PM
PART
Routine Airway Management
I
CHAPTER
Anatomy of Direct Laryngoscopy 1 cn
James Snyder and Steve Orebaugh
ORIENTATION The Tongue is a Dome of Muscle

The tongue is rooted in and rises up from two roughly
X-rays in supine and sniffing positions with correspond-
concentric U-shaped bones, the mandible and hyoid
ing illustrations help convey anatomy dynamics as well as
(Fig. 1-4). The bulk of the tongue is the intrinsic genio-
details (Fig. 1-1). Direct laryngoscopy (DL) requires dis-
glossus muscle, which arises from the mandible anteriorly
placement above a line of sight (LOS) between the upper
and extends fibers to the hyoid bone posterior (Fig. 1-4A).
teeth to the glottis, of the hyoid bone, tongue, and epiglot-
Laterally the tongue is secured to the hyoid by a verti-
tis. Hyoid bone movement forward depends on adequate
cal sheet of muscle, the hyoglossus (Fig. 1-4B). The floor
slack in the stylohyoid ligament (SHL). The tongue when
of the mouth is predominantly formed by the mylohyoid
flaccid acts likes a viscous mass. Control of the epiglottis
muscle, which slopes from attachments around the man-
depends on the type of blade used.
dible to form a midline raphe anteriorly and to the hyoid
bone posterior (Fig. 1-4C). This arrangement is compa-
rable to the levator ani that forms the floor of the pelvis.3
ANATOMY OF THE MOUTH
AND TONGUE Muscle Tone and the “Peardrop” Phenomenon
Tongue flaccidity and adhesion of the blade to the tongue
The most obvious oral impediments are the teeth and complicate finding and controlling the epiglottis. Lifting
tongue (Fig. 1-2). The tonsillar pillars and fauces are vis- the blade before each advance can break adhesion. Steps
ible on either side as they course from the soft palate to are kept small to avoid bypassing the epiglottis. Loss of
the base of the tongue, in effect creating a tubular inlet to lingual muscle tone requires additional attention. The
the oropharynx. tongue has a globular shape when the mouth is closed and
Laryngoscopy from the right corner of the mouth can muscle tone is normal (Fig. 1-4A). With loss of muscle
bypass the bulk of the tongue, shorten the distance to the tone, the tongue is easily distorted dorsally by contact
larynx, and lower (improve) the angle of approach to the with the blade as it is being inserted, and the tongue and
glottis, and has been successful in many cases where alter- epiglottis are readily pressed against the posterior pharyn-
natives failed. Practice is required to maintain orientation. geal wall (Fig. 1-5).
In code situations, the tongue may be found “slurred”
The Dorsal Tongue up against the palate as well as the posterior pharyngeal
The posterior third of the dorsum of the tongue looks wall, impairing bag-mask-ventilation (BMV) as well as
backward and contains numerous submucous adenoid laryngoscopy. Passing the blade between the blade and
collections and lymph follicles called the lingual tonsil. palate can cause trauma to soft tissues. A gauze pad enables
Hypertrophy of the lingual tonsil has been described as grasp of the flaccid tongue by its broad tip, to be pulled for-
a common and important cause of unpredicted difficult ward and then maintained forward by continuous positive
intubation where the epiglottis cannot be lifted from a airway pressure with BMV or by the laryngoscopy blade.
dorsal approach over the tongue (Fig. 1-3).1 Hypertrophic
lingual tonsils impair tongue displacement and are prone Larynx and Epiglottis
to bleed with minimal trauma. The potential for hemor- The larynx is a 4 cm long structure below an almost 2 cm
rhage should encourage early consideration of paraglottic inlet (Fig. 1-6). It overlies the 4th, 5th, and 6th cervical
straight blade technique.2 vertebra in adult males, higher in females and children.
Orebaugh_Ch01.indd 1 18/07/11 2:49 PM

2 PART I ■ ROUTINE AIRWAY MANAGEMENT
HB TC
CC
SHL
SP E
C D
F I GUR E 1 -1 X-ray laryngoscopy supine and during DL in sniffing position (aligned at dorsal C6), and corresponding illustra-
tions. A: In the neutral position, the hyoid bone (HB) is dorsal to the thyroid cartilage (TC) and therefore also to the glottis. The
SHL functions as a cable by which the larynx is suspended from the styloid process (SP), which can be seen in A, just behind the
anterior arch of the atlas. The posterior extensions of the hyoid bone and lateral walls of the thyroid cartilage abut the posterior
pharyngeal wall. B: During DL in the sniffing position (head elevation and a-o extension), the entire larynx is rotated forward.
Both the hyoid and thyroid cartilage are lifted forward from the pharyngeal wall. In particular, notice the hyoid is lifted anterior
to the glottis (compare C and D). Because LOS requires the hyoid forward of the thyroid cartilage, it appears that release of
tension in the SHL may be a mechanism by which head elevation facilitates DL. (A modified from Fuller MJ http://www.wikira-
diography.com/page/Lateral+Soft+Tissue+Neck+for+Foreign+Body, Case #1with permission;B modified from Nishikawa K,
Yamada K, Sakamoto A. A new curved laryngoscope blade for routine and difficult tracheal intubation. Anesth Analg.
2008;107:1248–52 with permission.)
DESIGN SERVICES OF

CHAPTER 1 ■ ANATOMY OF DIRECT LARYNGOSCOPY 3
Anterior tonsillar
pillar
Posterior tonsillar
pillar
Masseter muscle
Styloglossus muscle
Vallecula
Stylohyoid muscle
Epiglottis
A B Piriform recess
F I GUR E 1 -2 View into mouth.A: The anterior and posterior tonsillar pillars and palatine tonsil form an isthmus between
mouth and pharynx. Note the open space cephalad, under the palate. B: Laryngoscopy with a curved blade usually is over the
right dorsum of the tongue, directed to contact its broad leading edge against the midline fold of the HEL to “flip” the epiglottis
up against the blade (M).24 Laryngoscopy from the right corner of the mouth and along the base of the tongue (paraglossal) with
the straight blade often enables glottal view not possible with a curved blade, as it bypasses the bulk of the tongue, shortens the
distance to the larynx, and improves the angle of approach to the glottis (P). See chapter on Direct Laryngoscopy. (B revised from
Netter FH. Atlas of Human Anatomy. 4th ed. Philadelphia, PA: Saunders/Elsevier; 2006 with permission.).
A B C
F I GUR E 1 -3 Hypertrophic lingual tonsils (in the top 1/3 to ½ of each example above) can extend to or cover the tip and lateral
edges of the epiglottis (in the center). Lower part of each image is the soft palate. Manipulation of the friable tissue can cause
copious bleeding (Modified from Ovassapian A, Glassenberg R, Randel GI,The unexpected difficult airway and lingual tonsil hy-
perplasia: a case series and a review of the literature.Anesthesiology. 2002;97(1):124–132 with permission.)
DESIGN SERVICES OF

Genioglossus muscle Geniohyoid muscle

Genioglossus muscle
Geniohyoid muscle
Mylohyoid muscle Hyoglossus muscle
Condyle of
mandible
Digastric muscle Geniohyoid

(anterior) muscle
Mylohyoid muscle
Mylohyoid
Digastric muscle muscle
(posterior)
Stylohyoid ligament
Stylohyoid muscle
Hyoglossus muscle
Hyoid bone D View from mouth
C View from below
Hyoglossus
muscle
Mylohyoid
muscle
Hyoid bone
E
F I GU R E 1- 4 Muscles of the tongue. The hyoid normally is palpable at the junction of the neck and chin (A). DL in the midline
requires the tongue, epiglottis and hyoid displaced (arrows) across a line from the teeth to the glottis (dashed line). Although
limited by dentition and elasticity of the mouth, blade insertion from the corner of the mouth may provide a better angle (dotted
line). A-o extension (compare A and B) lengthens the space into which the tongue is displaced and stretches the tissues of the
submandibular space. Displacement of the tongue requires stretch of the floor of the mouth (anterolateral mylohyoid (C, D, E) and
midline geniohyoid (A, B), and of the suspending elements: the palatoglossus, styloglossus, stylohyoid, digastric muscles, and
tenses the SHL. Ease of passing the endotracheal tube from the right side of the mouth or adjacent to the base of the tongue
(paraglossal) is strongly influenced by whether molars are present (E).
DESIGN SERVICES OF

FIG U RE 1-5 X-ray laryngoscopy: normal vs. the

“peardrop phenomenon”. A: The diagram shows the
expected position of the laryngoscope blade (shaded)
relative to the tongue (cross-hatched) in the sniffing
position. Tongue is shown dorsal to the blade because
the blade displaces the tongue laterally as well as
forward. The blade tip reaches to just behind the hyoid.
Hyoid
The dashed line represents the anterior delineation
of the tongue. B: The “peardrop” phenomenon. The
tongue has “slurred” dorsally, to a shape called pear-
drop by Horton et al.23 The blade tip is beyond the
hyoid and held well back from it by the tongue, which
C2 is trapped by the blade. C: X-ray laryngoscopy of the
peardrop phenomenon. (A modified from Horton A,
Fahy L, Charters P. Factor analysis in difficult tracheal
intubation: laryngoscopy-induced airway obstruction.
C7 Br J Anaesth. 1990;65:801–805 with permission;
A C modified from Nishikawa K, Yamada K, Sakamoto A.
A new curved laryngoscope blade for routine
and difficult tracheal intubation. Anesth Analg.
Peardrop
Hyoid
C2
C7
B
DESIGN SERVICES OF

F I GUR E 1 -6 Laryngeal skeleton: Lateral X-ray and

corresponding illustration. The greater horns of the hyoid
bone (HB) and the lateral walls of the thyroid cartilage (TC)
abut the posterior pharyngeal wall, forming rigid struts for
the upper larynx. A piece of shellfish (arrow) is caught in
the piriform recess above the upper esophageal sphincter,
which is dorsal to the lower third of the dorsal plate of the
cricoid cartilage (CC). The thyroid cartilage is suspended
from the hyoid on three sides by a flexible sheet-like
ligament, the thyrohyoid membrane. A: X-ray: Airspace
(dark) outlines the tongue, valecula, and laryngeal inlet
and the trachea below the thyroid cartilage. The valecula
is the dark loop under the hyoid between the tongue and
epiglottis. B: Surface of laryngeal skeleton. The thyroid car-
tilage is secured at its inferior horn by an articulation to the
cricoid cartilage, which restricts their movement primarily
to flexion and extension. In this neutral to extended posi-
Cricothyroid articulation
tion, the hyoid is dorsal to thyroid cartilage due to tensed (under muscle)
SHL ligament, and the cricothyroid articulation is extended,
stretching the cricothyroid membrane. (A modified from Cricopharyngeus
muscle
Fuller MJ http://www.wikiradiography.com/page/Lateral+S
oft+Tissue+Neck+for+Foreign+Body, Case #1 with permis-
sion.)
C2 C3 C4 C5
Lateral thyrohyoid Pharyngeal Level of upper

ligament aponeurosis esophageal sphincter
B
It is suspended from the hyoid bone via a flexible sheet Often the operator’s view is experienced and imaged
of ligament, the thyrohyoid membrane (Fig. 1-6). The as follows.
hyoid bone is secured dorsally to the skull via the SHL.
The hyoid and thyroid cartilage are open-ring structures Laryngeal Inlet and Epiglottis Control
that form the anterior wall of the lower pharynx. The la- The laryngeal inlet has considerably more depth than is
ryngeal skeleton can swing well forward of the posterior apparent to the operator or in photographs or training
pharyngeal wall, because it is secured to the somatic skel- diagrams (Figs. 1-6–1-8). It may be helpful to visualize a
eton primarily by the SHL above and the cricopharyngeus “Robin Hood hat” obscuring the glottis (Fig. 1-9).
muscle at C6. The upper esophageal sphincter is formed
from fibers of the cricopharyngeus muscle, which extends Leveraged Elevation of the Epiglottis with the
from one side of the cricoid arch to the other; the cricoid Curved Blade: The “EpiFlip”
cartilage is secured to the posterior pharyngeal wall by the Often curved blade placement is described imprecisely,
tone of the cricopharyngeus muscle.3,4 such as “in the vallecula,” or “against the hyoepiglottic
ligament.” Dissection makes clear and blade-based video
The Larynx: Operator and Alternative Views routinely confirms there is a “sweet spot” where pressure
The DL learning curve has been substantially altered by causes a leveraged upward movement of the epiglottis—a
Levitan’s development of a video system to capture the “flip.” The sweet spot, on the mid-portion of the median
operator’s view and his promotion of learning the opera- fold of the hyoepiglottic ligament (HEL), cannot directly
tor perspective in advance of clinical practice. Although be seen in DL.
published emphasis relating to technologic development In DL, the optimal point is located by quickness of
is largely focused on indirect laryngoscopy, we ascribe to visible epiglottis response to small oscillations of blade
Levitan’s5–10 work much of our reorientation to the dy- tip pressure. Pressure oscillations may be generated by
namic three-dimensional nature of DL mechanics related moving the blade or by quick gentle pressing movements
below. externally against the thyroid cartilage, or sometimes the
DESIGN SERVICES OF

Epiglottic
Greater horn tubercle
of hyoid bone
Vestibular
Aryepiglottic fold
fold
Ventricle
Piriform of larynx
recess of Vocal fold Piriform recess
laryngopharynx (cord)
Aryepiglottic fold
Cuneiform tubercle Rima glottidis Posterior cartilages

A Corniculate tubercle
Interarytenoid notch
B
Epiglottis
Epiglottis
Glottic rim
Vocal cord
Vestibular cord Glottic rim
Posterior cartilages Vocal cord (intermembranous)
Glottic rim
Vestibular cord
(intercartilaginous)
Piriform recess Interarytenoid notch
C D
Epiglottis
Larngeal ventrical Glottic rim

Vestibular cord
Vocal cord
Aryepiglottic fold
Arytenoid cartilages
Interarytenoid notch
Posterior cartilages
E
F I GUR E 1 -7 Operator views of the glottis convey less depth than must actually be traversed. A: Illustration of anatomy from
operator perspective. B: The elevated epiglottis is the broad light band (clock position 10 to 2) distorted by proximity to the lens.
The larynx is lifted forward, exposing the piriform recess behind. Advance of the ET (circle) toward the glottis can be impaired by
“snagging” on prominent posterior cartilages, dislocation of which is a relatively common injury. C, D, E: A slightly more edema-
tous larynx in positions of inspiration, phonation and whisper.
DESIGN SERVICES OF

A B
F I GUR E 1 -8 Suboptimal elevation of the epiglottis. Excellent control of the tongue may provide only a clear view of the epi-
glottis, elevation of which requires a completely different understanding. A: Viewed with a straight blade from the right corner
of the mouth, a bright epiglottis tip shadows the left posterior cartilage. The “sweet spot” on the HEL is difficult to locate with
the narrow tip of the Miller blade, shown, compared to broader blade tips such as the Macintosh or Henderson. B: The tip of the
epiglottis is curving up toward the lens on a blade-based system. The irregular mucosal surface above the epiglottis suggests the
blade tip has not advanced past the base of the tongue. (Source = Orebaugh 1st ed?)
hyoid. Pressing externally can ascertain positioning more Usually the two forms of bimanual laryngoscopy are
effectively than moving the blade tip. Also external pres- considered alternatives, but voice-controlled head eleva-
sure may facilitate movement of the “sweet spot” toward tion by an assistant allows a very efficient combined ap-
the blade tip rather than depending only on exploration plication. The assistant lifting before or soon after blade
with the blade.8 Understanding various blade tip locations insertion minimizes left hand lifting force and frees the
that cause a sluggish and inadequate epiglottis lift are a right hand to ELM and if necessary fine-tune the assis-
basis for repositioning trials (Fig. 1-10). tant’s head lift.
Bimanual Laryngoscopy: One Term for Two

Valuable Techniques
ANATOMY OF POSITIONING FOR DL
The term bimanual laryngoscopy has been applied to two
techniques.11 Bimanual laryngoscopy originally referred to The mechanisms by which axial positioning influences
routine use of the right hand to move the head through a DL have not been welldefined.16,17 Pioneer laryngeal sur-
range of positions, as described by Murphy: “. . .the sniff- geon Chevalier Jackson18 is often noted to have recom-
ing position is a starting position only…make it dynamic. mended “the head in full extension.” Anesthesiology
Use your right hand behind the head to lift it, flex and ex- literature transitioned gradually away from extension to
tend the head on the neck, rotate it left and right as needed to favor a “sniffing position”—mild elevation of the head
bring the target into view. Once the best view is obtained, with atlanto-occipital extension, which is detailed below.
have an assistant hold the head in this position.”12 Recent articles have acknowledged reports of benefit
The operator using his right hand for external laryn- from head elevation, including “maximal” head eleva-
geal manipulation (ELM) is the other technique called tion.
bimanual laryngoscopy. The high value of operator ELM Various observations conclude flexion can facilitate
for novices as well as experienced practitioners justifies DL in difficult cases. Studies in anesthetized patients led
routine early employment.10,13,14 For novices, incidence of Hochman et al19 to recommend “flexion of both the head
no visible glottis was reduced from 11% to zero, and when and neck (chin to chest) [as] the ideal position to in-
the POGO was less than 20%, the average improvement in tubate the patient whose glottis is difficult to observe
POGO was greater than 50%.8 Programmed external ma- by means of routine positions.” Levitan observed that
nipulation by an assistant (Backward, Upward, Rightward in each of nine cadavers glottic exposure was improved
Pressure, BURP) is substantially less effective.15 by raising the head from flat to moderate to maximal
DESIGN SERVICES OF

Hyoid HEL AEF

bone
B C
F I GUR E 1 -9 The laryngeal inlet as an elongated “Robin Hood hat with tipper and ear-pads.” A: Lateral illustration “cut away”
to show multiple levels. B: X-ray (from Figs.1-1A and 1-6). C: During direct laryngoscopy. The epiglottis (E) forms the entire top
surface of the hat, including a long brim that typically hides the glottis/face at the back of the hat. The hyoid bone forms a crude
lifting handle above the brim. A tear-shaped shadow under the hyoid is formed by the median fold of the HEL. Pressure against
the HEL “tips” the hat brim up. The lateral walls of the inlet are the aryepiglottic folds (AEF)—delicate curved lines from the tip
of the epiglottis to blurred “earpad” densities, which are the arytenoid, or posterior, cartilages.
elevation. Average POGO improved from 31% to 64% thyroid cartilage of a slender person. The hyoid might be
to 87%.4 By the addition of maximal head elevation and more palpable by its sides, above the thyroid cartilage. The
ELM, Schmidt et al were able to expose at least the pos- subject should keep his head horizontal while moving it
terior cartilages in all but two in a series of 1,500 OR fore and aft in an exaggerated way, akin to a pigeon when
cases.20 walking (Fig. 1-12). Movement backward comprises neck
Notably, Chevalier Jackson completely reversed his extension and a-o flexion, and movement forward is cervi-
initial recommendation for extension. He later affirmed, cal flexion and a-o extension. With head movement back-
“Overextension of the patient’s head is a frequent cause of ward, the hyoid can be felt to move posterior to the thy-
difficulty. If the head is held high enough [even a-o] exten- roid cartilage, and with forward movement, the hyoid can
sion is not necessary…” (Fig. 1-11).21 Other strongly probe felt to move in front of the thyroid cartilage. Because
flexion/head elevation comments are in the [Web access]. the tongue and epiglottis are hyoid-based and the glottis is
Jackson’s lifelong practice of continuous left hand laryn- in the thyroid cartilage, this palpable movement suggests
goscopy during all his laryngeal procedures conferred how flexion might facilitate DL.
great sensitivity to which positioning would provide opti- Clearly, the anatomy of the airway is complex, and its
mal laryngeal exposure. relevance to airway management involves both static and
dynamic aspects. The more dynamic characteristics, related
Palpation of Flexion Effect on the Antero- to optimal positioning, appropriate placement of the laryn-
Posterior Relationship between the Hyoid goscope blade, lifting forces, and the bimanual approach to
Bone and Thyroid Cartilage laryngoscopy, are considered in more detail in Chapter 5,
Palpation of this dynamic relationship is helpful to convey “Technique of Direct Laryngoscopy.” Innervation of key
its prominent effect. To do so, hold the index and third airway structures is discussed in Chapter 8, “Regional
finger on the anterior prominences of the hyoid bone and Anesthesia Blocks for Awake Intubation.”
DESIGN SERVICES OF

HB
HEL
A
C D
E G
F I GU R E 1 -1 0 Relationship of the blade tip to the median fold of the HEL. A: HEL curvature at rest and B: pressed at midpoint
to leverage elevation of epiglottis above LOS. Suboptimal epiglottis lift due to positioning in various locations can appear similar
on DL (eg, Fig.1-8). Familiarity with these suboptimal locations can guide repositioning trials. C: Shallow placement. When a
blade-based view is available, mucosal irregularity of the tongue may be apparent, as in Fig. 1-8B. D: Blade tip abutting rather
than dorsal to hyoid: although the optimal site is only millimeters deeper, abutment prevents sliding the tip dorsal to the hyoid
and against the HEL. E: Blade tip is below the hyoid at the base of the HEL; lifting still causes only a sluggish elevation. If the tip
is midline, optimal position might result from advance of the blade tip or external pressure on the thyroid cartilage. F: If the tip is
not midline, advancing the tip into the valecula on either side of the median fold of the HEL still provides less than full elevation.
G: Placement only millimeters past the optimal point (that is, closer to the epiglottis tip) can prevent elevation, or push the epi-
glottis caudad, or flex it back on itself. Lifting the blade tip slightly may flip the epiglottis up. H: The blade tip is positioned as in
G, but lift is prevented by the flaccid tongue slurred dorsally between the blade and the hyoid (Peardrop phenomenon, Fig. 1-5).
DESIGN SERVICES OF

FIG U RE 1-10 (Continued)
G H
FIG U RE 1-11 Head-elevated position for DL, by

Chevalier Jackson (1934). For introduction of the laryngo-
scope, Jackson recommended “The patient’s vertex should
be 10 cm. higher than the level of the top of the table.”
Jackson referred to the position now called “sniffing” as
“normal recumbency.”21
10 cm
FIG U RE 1-12 Palpable demonstration of fore and aft

movement of the hyoid relative to the thyroid cartilage.
The thyroid cartilage is the most prominent structure
and is notched at the top in the midline. The hyoid is
the first firm mass below the mandible, at the junc-
tion of the neck and chin. It is wider than the thyroid
cartilage and can be felt just above the sides of that
prominence. Fore and aft movement of the head causes
readily palpable antero-posterior movement of the hyoid
relative to the thyroid cartilage.
REFERENCES 5. Levitan RM, Mechem CC, Ochroch EA, et al. Head-elevated

laryngoscopy position: improving laryngeal exposure dur-
1. Ovassapian A, Glassenberg R, Randel GI, The unex- ing laryngoscopy by increasing head elevation. Ann Emerg
pected difficult airway and lingual tonsil hyperplasia: a Med. 2003;41:322–330.
case series and a review of the literature. Anesthesiology. 6. Levitan RM. The Airway Cam Guide to Intubation and
2002;97(1):124–132. Practical Emergency Airway Management. Wayne, PA:
2. Al Shamaa M, Jefferson P, Ball DR. Lingual tonsillar hy- Airway cam Technologies, inc.; 2004.
pertrophy: airway management using straight blade direct 7. Levitan RM, Goldman TS, Bryon DA, et al. Training with
laryngoscopy. Anesth Analg. 2004; 98(3):874; author reply video imaging improves the initial intubation success rates
874–875. of paramedic trainees in an operating room setting. Ann
3. Last RJ. Last’s Anatomy: Regional and Applied. 11th ed. Emerg Med. 2001;37:46–50.
Edinburgh; New York: Elsevier/Churchill-Livingston; 8. Levitan RM, Chudnofsky C, Sapra N. Emergency airway
2006. management in a morbidly obese, noncooperative, rapidly
4. Jackson C, Jackson CL. Bronchoscopy Esophagoscopy and deteriorating patient. Am J Emerg Med. 2006;24:894–896.
Gastroscopy: A Manual of Peroral Endoscopy and Laryngeal 9. Levitan RM. Patients safety in emergency airway manage-
Surgery. 3rd ed. Philadelphia, PA: WB Saunders Co.; ment and rapid sequence intubation: metaphorical lessons
1934:59. from skydiving. Ann Emerg Med. 2003;42:81–87.
DESIGN SERVICES OF

10. Levitan RM, Mickler T, Hollander JE. Bimanual laryngos- 17. Adnet F, Borron SW, Lapostle F, et al. Study of the “sniffing
copy: a videographic study of external laryngeal manip- position” by magnetic resonance imaging. Anesthesiology.
ulation by novice intubators. Ann Emerg Med. 2002;40: 1996;85:787–793.
30–37. 18. Jackson C. The technique of insertion of intratracheal insuf-
11. Murphy MF, Hung OR, Law JA. Tracheal intubation: flation tubes. Surg Gynecol Obstet.1913;17:507–509.
tricks of the trade. Emerg Med Clin North Am. 2008;26: 19. Hochman II, Zeitels SM, Heaton JT. Analysis of forces
1001–1014. and position for direct laryngoscopic exposure of the an-
12. Murphy BM. Bringing the larynx into view: a piece of the terior vocal folds. Ann Otol Rhinol Laryngol. 1999;108:
puzzle. Ann Emerg Med. 2003;41:322–323. 715–724.
13. Wilson ME, Spiegelhalter D, Robertson JA, et al. Predicting 20. Schmitt, HJ, Mang H. Head and neck elevation beyond the
difficult intubation. Br J Anaesth. 1988;61:211–216. [A re- sniffing position improves laryngeal view in cases of diffi-
duction in epiglottis-only or no-epiglottis views, from 9.3% cult direct laryngoscopy. J Clin Anesth. 2002;14:335–338.
to 5.9%.] 21. Jackson C, Jackson CL. Bronchoscopy Esophagoscopy and
14. Benumof JL, Cooper SD. Quantitative improvement in Gastroscopy: A Manual of Peroral Endoscopy and Laryngeal
laryngoscopic view by optimal external laryngeal manipula- Surgery. 3rd ed. Philadelphia, PA: WBSaunders Co.; 1934:
tion. J Clin Anesth. 1996;8:136–140. [Improvement by one 89–90 and 103.
grade.] 22. Netter FH. Atlas of Human Anatomy. 4th ed. Philadelphia,
15. Levitan RM, Kinkle WC, Levin WJ, et al. Laryngeal view PA: Saunders/Elsevier; 2006.
during laryngoscopy: a randomized trial comparing cricoid 23. Horton A, Fahy L, Charters P. Factor analysis in difficult
pressure, backward-upward-rightward pressure, and biman- tracheal intubation: laryngoscopy-induced airway obstruc-
ual laryngoscopy. Ann Emerg Med. 2006;47(6):548–555. tion. Br J Anaesth. 1990;65:801–805.
16. Chou H-C, Wu T-L. A reconsideration of three axes 24. Nishikawa K, Yamada K, Sakamoto A. A New Curved
alignment theory and sniffing position. Anesthesiology. Laryngoscope Blade for Routine and Difficult Tracheal
2002;97:753. [Correspondence.] Intubation Anesth Analg 2008;107:1248–52.
DESIGN SERVICES OF

CHAPTER
Mask Ventilation 2 cn
Mark Backeris and Patricia Dalby
Concept in which chin lift, head extension, and mouth opening are
provided. Placement of the patient in “sniffing position,”
with the cervical spine flexed and the head extended, also
Mask ventilation is an effective, noninvasive means of
contributes to this. Mask fit can be optimized with the
providing ventilation and oxygenation in the decom-
choice of mask shape and with appropriate inflation of
pensated or unconscious patient. Maintenance of a pat-
the air-filled bladder, or cushion, which surrounds most
ent airway with mask ventilation is an important skill
modern ventilation masks. As the mask is placed over the
that requires understanding and experience to perform
mouth and nose, it is imperative that pressure is applied
well. Furthermore, the ability to ventilate by mask is life-
from above as the jaw is lifted into the mask. This is most
supporting or even life-saving when direct laryngoscopy
effectively performed by using the thumb and forefinger
proves difficult. In some scenarios, ventilation by mask
of the left hand to apply the mask, while the remaining
may be all the airway management necessary to ensure
fingers pull the boney mandible upward. This chin lift-jaw
temporary oxygenation and ventilation, while a revers-
thrust maneuver prevents the soft tissue obstruction of the
ible condition is addressed, and the patient is expected to
airway that will occur if the mandible is displaced in a
then resume spontaneous ventilation. When endotracheal
posterior direction with mask pressure in the unconscious
intubation is necessary in the elective, fasted setting, as in
patient, or if the fingers apply pressure to the floor of the
the operating room, initial ventilation with the face mask
mouth, obstructing the oral cavity.3 It is particularly useful
should precede attempts at intubation in the apneic patient.
to “hook” the fifth finger behind the angle of the mandible
In emergent airway management scenarios, face mask
to aid in lifting it upward. When attempting to open the
ventilation is often withheld after unconsciousness is in-
airway for bag-mask ventilation, it is important to avoid
duced, in order to avert gastric insufflation and the poten-
firm occlusion of the teeth by cephalad pressure with the
tial for regurgitation (“rapid sequence induction” or “rapid
fingers on the body of the mandible, because it will be
sequence intubation”). However, the decision to withhold
impossible to thrust the jaw forward. When making a seal
mask ventilation after the delivery of drugs for an emer-
proves difficult, a two-hand technique is preferred. This
gent intubation is somewhat controversial.1 In a conscious
may utilize the thumb-forefinger technique on the mask,
patient who is dyspneic and hypoxemic, assistance of ven-
as described above, or the thenar eminences and thumbs
tilation with positive pressure or simply high-flow oxygen
may be used for downward pressure, while the other eight
is appropriate to obtain adequate preoxygenation in prep-
fingers are placed on the jaw and behind the angle of the
aration for intubation. In an unconscious patient with a
mandible to provide jaw thrust and chin lift.
reduced oxygen saturation, a period of low-pressure mask
Mask ventilation also necessitates a source of pressure
ventilation is necessary to avert severe hypoxemia dur-
to move gas into the airway. Depending upon the setting,
ing attempted laryngoscopy, and it should continue after
the oxygen source in bag-mask ventilation may be a hospi-
the delivery of the hypnotic and relaxant if high oxygen
tal wall source, oxygen tank with regulator, or an anesthe-
saturations cannot be restored. Such attempts should be
sia machine and circuit. Effective ventilation is confirmed
conducted in association with cricoid pressure to reduce
by visible chest rise and audible breath sounds, as well as
gastric insufflation.2 An assortment of face masks for ven-
the presence of exhaled CO2, if monitored (as is typical in
tilation is shown in Fig. 2-1. Clear masks are preferred to
the operating room). In addition, the “feel” of the ventila-
other types, so that regurgitation or vomitus is immedi-
tion bag may provide clues to a patent airway—when little
ately apparent.
or no resistance is met to attempts at ventilation, a leak is
likely. When compliance is very poor and high pressures
Evidence (more than 25 to 30 cm H2O) are required, there is likely
to be an upper airway obstruction. Additional causes of
Effective mask ventilation requires an open airway and a high ventilation pressures that should be considered are
tight seal between the mask and the face. Patency of the gastric insufflation, pneumothorax, “stacking” of breaths
airway can be optimized with a “triple airway maneuver” due to insufficient time for exhalation, and poor lung or
13

chest wall compliance. High inflation pressures may con-

tribute to gastric insufflation and regurgitation and should Preparation
be avoided if possible.
Airway obstruction in the unconscious individual is ● Attach bag-mask apparatus to oxygen source
usually attributed to relaxation of the tongue, with pos- ● Assure flow of oxygen
terior displacement of its muscular mass, occluding the ● Select face mask of correct size and attach to bag-mask or
airway at oropharyngeal levels. Studies with magnetic res- anesthesia circuit
onance imaging in sedated adults suggest that the soft pal- ● Place patient in optimal position: neck flexion, head
ate plays a very important, and perhaps predominant, role extension (“sniffing” position)
in this phenomenon.4 Doubtless, both mechanisms may
contribute, and overcoming this obstruction is paramount
in ensuring oxygenation and ventilation. Either oropha- Procedure (Figs. 2-2 to 2-12)
ryngeal or nasopharyngeal airways should be used to com-
plement mask ventilation when obstruction occurs, and ● Open the airway with “triple airway maneuver”: head ex-
if ineffective, both may be used together (Figs. 2-2–2-7). tension, mouth opening, chin lift (in some patients, this
Both of these aids must be sized appropriately, or else they may be all that is required to resume ventilation).
may become ineffective or even make obstruction worse. ● Place the mask on the patients face, using the thumb and
Various definitions of difficult mask ventilation (DMV) forefinger of the left hand on the mask, and the remaining
have arisen in the literature, but most include the need to three fingers on the boney mandible, elevating it into the
resort to two provider assisted mask ventilation along with mask; the small finger should be hooked around the angle
the clinical signs of oxygen desaturation and inadequate of the mandible to provide jaw thrust. It can be difficult to
CO2 exchange, in the setting of poor chest excursion. At obtain an adequate jaw thrust while the mouth is closed
times, mask ventilation may remain difficult or impossible and the teeth are touching. For this reason, some mouth
despite optimal technique (Figs. 2-8 and 2-9), even with opening or the use of an oral airway is advised.
the use of nasal and/or oral airways. Several predictors ex- ● Squeeze the bag with the right hand, until chest rise is evident
ist for evaluating the possibility of encountering DMV, in- ● Ensure optimal seal of the mask on the face: leakage of gas
cluding the presence of a beard, obesity, the lack of teeth, should not occur with inflation pressures up to 25 cm H2O
and a Mallampati score of either III or IV.5 Additionally, it ● If seal is inadequate, reposition mask or change to a differ-
has been shown that operator experience is an important ent size mask
factor in avoiding DMV. An independent study has shown ● If seal is intact, but ventilation is ineffective, suspect air-
that, on average, it takes approximately 25 mask ventila- way obstruction and ensure optimal positioning, mouth
tion procedures to attain an 80% success rate.6 opening, and jaw thrust. If not effective, then place oro-
DMV may occur in up to 1.4% of cases, but impos- pharyngeal or nasopharyngeal airway
sible mask ventilation is much less common.5,7 Under these ● Confirm adequate ventilation with chest rise, humidifica-
circumstances, assistance should be obtained and a two- tion in mask, symmetric breath sounds on auscultation,
handed, two-person mask technique utilizing the methods and presence of expired CO2 (if capnometry is available)
mentioned above must be employed (Fig. 2-10). If only
unskilled assistance is available (ie, no experience in air- Practicality
way management), then the provider in charge of the air-
● Simple, inexpensive, portable airway support maneuver
way should use both hands to secure the mask seal, while
● Requires considerable practice and experience to perform
his/her assistant squeezes the anesthesia bag or resuscita-
well
tion bag (Fig. 2-11). An intraoral appliance that aids in
the maintenance of pharyngeal patency by mandibular
advancement called the EMA-T has also been described
Indications
(Fig. 2-12).8 ● Altered mental status with inadequate or obstructed
In the case of an edentulous patient, it becomes dif- ventilation
ficult to maintain an adequate seal because of the absence ● Unconscious patient with apnea or inadequate ventilation
of tooth structure for soft tissue to rest upon, creating nu- ● Cardiac arrest
merous air leaks. Effective mask ventilation may be bet- ● Pre oxygenation before intubation attempts
ter achieved by using a “lower lip” facemask placement. ● Ventilation after induction of anesthesia in elective sur-
This is performed by placing the lower mask edge above gical cases, preceding placement of endotracheal tube or
the lower lip while maintaining head flexion (Fig. 2-13). laryngeal mask airway
When used correctly, this method has been shown to re- ● Administration of anesthesia gases throughout certain
duce air leak in the edentulous patient by 80% to 100%.9 surgical cases

CHAPTER 2 ■ MASK VENTILATION 15
FIG U RE 2-1 Examples of face masks for bag-mask

ventilation.
FIG U RE 2-2 An array of oropharyngeal airways to

assist with bag-mask ventilation.
FIG U RE 2-3 An array of nasopharyngeal airways

to assist with bag-mask ventilation.

F I GUR E 2 -4 Proper placement

of an oropharyngeal airway, show-
ing effective separation of dorsal
tongue from posterior oropharyn-
geal wall.
F I GUR E 2 -5 Proper placement of

a nasopharyngeal airway, showing
effective separation of soft palate
from posterior wall of nasopharynx.

FIG U RE 2-6 Improper size

and placement of oropharyngeal
airway, showing potential increase
in obstruction from tongue
displacement.
FIG U RE 2-7 Improper size of

nasopharyngeal airway, showing
failed separation of soft palate
from nasopharyngeal wall.

F I GUR E 2 -8 Effective application of the face

mask in the unconscious patient, with thumb and
forefinger holding mask to face, while the other
three fingers pull the mandible up into the mask,
creating seal and enacting a chin lift-jaw thrust
maneuver simultaneously.
F I GUR E 2 -9 Detail of application of face mask,

showing fifth finger “hooked” behind the man-
dibular angle, pulling mandible upward into mask
with effective jaw thrust. Some mouth opening
may facilitate jaw thrust.
F I GUR E 2 -1 0 Effective two-person mask tech-

nique allows the most skilled provider to perform
a two-handed mask seal with jaw thrust, while the
second operator uses one hand to enhance mask
seal and the other to squeeze the bag. This tech-
nique should be employed with oral and/or nasal
airways in place to optimize ventilation attempts.

FIG U RE 2-11 When only one skilled provider

is available, he/she should place both hands on
the mask, providing an effective seal, while the
unskilled assistant squeezes the bag.
FIG U RE 2-12 EMA-T device used for man-

dibular advancement.
FIG U RE 2-13 Using a “lower lip” facemask

placement on an edentulous patient performed
by placing the lower mask edge above the
lower lip while maintaining head flexion.

Contraindications Complications
● Full stomach or risk for regurgitation (however, if hy- ● Ineffective ventilation with hypoxia and/or hypercarbia
poxemia occurs, the theoretical risk of aspiration is out- ● Gastric insufflation
weighed by the real occurrence of tissue injury from ● Regurgitation/aspiration of gastric contents
hypoxia: mask ventilation should be carried out with cri- ● Trauma or bleeding from oral or nasal airways
coid pressure) ● Laryngospasm, bronchospasm, or vomiting due to stimu-
● Potential cervical spine injury (avoid cervical flexion or lation from oral or nasal airways (especially if placed too
head extension: manual, in-line immobilization should be deeply)
applied before attempts at direct laryngoscopy)
● Severe facial trauma, precluding mask placement or seal
● Upper airway foreign body obstruction: attempts should
be made to clear the airway first with appropriate abdomi-
nal or chest thrusts
REFERENCES 6. Komatsu R, Kasuya Y, Yogo H, et al. Learning curves for

bag-and-mask ventilation and orotracheal intubation: an
1. El-Orbany M. Rapid sequence induction and intubation: application of the cumulative sum method. Anesthesiology.
current controversy. Anesth Analg. 2010;110:1318–1325. 2010;112:1525–1531.
2. Ruben H, Knudsen EJ, Carugati G. Gastric insufflation in 7. Salem MR, Ovassapian A. Difficult mask ventilation:
relation to airway pressure. Acta Anaesth Scand. 1961;5: what needs improvement? Anesth Analg. 2009;109(6):
107–114. 1720–1722.
3. McGee JP, Vender JS. Nonintubation management of 8. Kuma ST, Woodson LC, Mathru M, et al. Effect of progres-
the airway: mask ventilation. In: Benumof JL, ed. Airway sive mandibular advancement on pharyngeal airway size in
Management: Principles and Practice. St. Louis, MO: Mosby; anesthetized adults. Anesthesiology. 2008;109:605–612.
1996:228–254. 9. Racine SX, Solis A, Hamou NA, et al. Face mask ventilation
4. Mathru M, Esch O, Lang J, et al. Magnetic resonance imag- in edentulous patients: a comparison of mandibular groove
ing of the upper airway. Anesthesiology. 1996;84:273–279. and lower lip placement. Anesthesiology. 2010;112(5):
5. El-Orbany M, Woehlck H. Difficult mask ventilation. Anesth 1190–1193.
Analg. 2009;109(6):1870–1880.

CHAPTER
Noninvasive Ventilation 3 cn
Stephen M. McHugh and Mario Montoya
Concept obstructive pulmonary disease (COPD) and cardiogenic

pulmonary edema, NIPPV has been shown to decrease
intubation rates and in-hospital mortality.4,5 As experi-
Noninvasive positive pressure ventilation (NIPPV) is the
ence with NIPPV grows, it is being evaluated in a growing
administration of ventilatory support without the use
number of scenarios, including postextubation respiratory
of an invasive artificial airway such as an endotracheal
failure (Fig. 3-2), as a component of ventilator weaning in
tube, tracheostomy tube, or laryngeal mask airway. Its
the ICU and as a method to provide ventilatory support to
use has been rapidly growing since its introduction in
patients with do-not-intubate status.6–8 Although the range
the late 1980s and early 1990s1,2 and it is now utilized
of conditions responsive to NIPPV is expanding, patient
as an adjunct to existing medical therapies or even as an
selection is still key to its successful implementation.
alternative to endotracheal intubation for selected condi-
tions. The main advantages of NIPPV are the ability to
provide ventilatory support to a patient without the need
for sedation and without bypassing airway defenses, both Evidence
of which are necessary with invasive ventilation. Perhaps
the most familiar use of NIPPV is for patients suffering Successful use of NIPPV requires correct selection of both
from obstructive sleep apnea for which it is considered the patient and equipment. Although the two acute condi-
standard of care3 and is provided by portable home devices tions most likely to respond to NIPPV are exacerbations
(Fig. 3-1). However, in other groups of patients, most of COPD and congestive heart failure, patients must be
notably those suffering from exacerbations of chronic evaluated on an individual basis for suitability for NIPPV.
F I GURE 3 -1 An example of a bilevel
positive pressure ventilation device with an
integrated humidifier. Newer devices are much
smaller in size than older models.
(©ResMed 2010. Used with permission.)
21

F I GURE 3 -2 This image shows the effects of

30 minutes of NIPPV on computer tomography lung
volumes in a patient with acute respiratory failure
after abdominal surgery. Note the decrease in
poorly aerated lung regions following NIPPV.
(From Jaber S, Chanques G, Jung B. Postoperative
noninvasive ventilation. Anesthesiology.
Tables 3-1 and 3-2 list criteria to consider when evaluating guides provided by the manufacturer. For the most com-
a patient for NIPPV. monly used oronasal mask, the patient is instructed to
NIPPV can be provided via a variety of different slightly open their mouth and the smallest mask that con-
interfaces. The characteristic that they all share is the ability tacts the bridge of the nose, the area just lateral to the cor-
to provide positive pressure. Oronasal masks were among ners of the mouth, and the area just below the lower lip
the earliest interfaces and are still the most commonly is chosen (Fig. 3-8).10 Selecting a mask larger or smaller
used (Figs. 3-3 and 3-4).9 These masks cover both the nose than this may result in patient discomfort and air leaks.
and the mouth. They may be particularly effective for an Next, the mask must be secured to the patient using the
acutely dyspneic patient as these patients tend to breathe attached head straps. The head straps on today’s oronasal
through their mouths rather than their noses.10 However, masks are adjustable in multiple areas and the manufac-
these masks increase the risk of aspiration in a vomiting turer’s instructions will provide detailed information on
patient because they interfere with the expectoration of obtaining the optimal fit for each model. However, for
gastric contents. Quick-release mechanisms on newer oro- all NIPPV interfaces, the general rule applies that the
nasal masks decrease this risk but require the patient to be head straps must be applied securely enough to prevent
awake and alert in order to release their mask. Nasal masks dislodgement with patient movement while avoiding the
decrease the aspiration risk and allow the patient to speak side effects of over-tightening. Applying the mask too
while receiving NIPPV, but they increase the risk of air tightly will increase patient discomfort and potentially
leaks through the mouth (Figs. 3-5 and 3-6). Mouthpieces, lead to skin irritation and even necrosis and ulceration.
nasal pillows (Fig. 3-7), total face masks, and helmets may In general, the practitioner should be able to slip one fin-
also be used to provide NIPPV. Each interface has its own ger between the strap and the patient’s head and there
set of advantages and disadvantages (Table 3-3). should be no skin bulging or erythema evident around
Once an interface is chosen, the proper fit must be the edges of the mask (Fig. 3-9). This will limit compli-
obtained. First, the correct size is determined using sizing cations due to excessive pressure while still keeping air
DESIGN SERVICES OF

CHAPTER 3 ■ NONINVASIVE VENTILATION 23
Table 3-1
Clinical Indications for NIPPV
1. Moderate to severe dyspnea

2. Tachypnea (>24 breaths/minute)
3. Increased work of breathing (accessory muscle use,
paradoxical abdominal motion)
4. Hypercapnia (PaCO2 > 45mmHg, pH < 7.35)
5. Hypoxemia (PaO2/FiO2 < 200)
Adapted from Soo Hoo GW. Ventilation, noninvasive. 2010. http://

emedicine.medscape.com/article/304235.
Table 3-2
Selection Criteria for NIPPV
1. Patient is conscious and cooperative

2. Patient can protect airway
3. Patient is hemodynamically stable
4. No active gastrointestinal bleeding
5. No impairment in swallowing FIG U RE 3-3 Example of an oronasal mask. Masks are
6. No facial deformities impairing fit of the interface available in a variety of different sizes and models.
Adapted from Antonelli M, Pennisi MA, Montini L. Clinical review:

noninvasive ventilation in the clinical setting—experience from the past
10 years. Crit Care. 2005; 9(1):98–103.
FIG U RE 3-4 A patient wearing an

oronasal mask.
DESIGN SERVICES OF

FIG U RE 3-6 A patient wearing a nasal mask. Note that the

mouth is uncovered, allowing the patient to speak, eat, and
expectorate secretions but also increasing the risk of air leaks
through the mouth.
F I GUR E 3 -5 Example of a nasal mask.

F I GUR E 3 -7 A patient demonstrating nasal

pillows. This type of interface allows access to
the skin of the face and does not cover the
mouth but can cause pressure sores of the
nares if applied too tightly.
DESIGN SERVICES OF

Table 3-3
Advantages and Disadvantages of Patient Interfaces Used in NIPPV
Interface Advantages Disadvantages

Oronasal mask Reduces air leakage through mouth Increased aspiration risk
Decreased airway resistance Increased sensation of claustrophobia
Mask must be removed to expectorate
secretions, speak, and eat
Nasal mask Decreased sensation of claustrophobia Mouth leaks
Low risk of aspiration Higher resistance through nasal passages
Allows patient to clear secretions, speak, and eat Eye irritation
Nasal pillows Increased access to skin of the face Pressure sores around nares
Mouthpieces No headgear required Nasal air leakage
Low risk of aspiration Hypersalivation
Adapted from Pilbeam SP, Cairo JM, eds. Mechanical Ventilation: Physiological and Clinical Applications. 4th ed. St. Louis, MO: Mosby; 2006.
FIG U RE 3-8 A patient wearing an appro-

priately sized oronasal mask. Note that the
mask extends from the bridge of the nose
to just below the lower lip and just lateral to
each corner of the mouth.
FIG U RE 3-9 An oronasal mask with head

straps adjusted to the appropriate tension. Note
that one finger can be placed between the strap
and the patient’s skin.
DESIGN SERVICES OF

leaks to a minimum. Lack of patient response to NIPPV ● If the seal is inadequate and there is excessive air leak-
may be addressed by refitting the interface or choosing age, re seat the interface by lifting it away from the pa-
a different type of interface; however, establishment of tient’s face and placing it back in the correct position and
a definitive invasive airway should not be delayed if the reevaluate head-strap tension, interface size, and type of
patient’s condition is deteriorating. interface (small air leaks are to be expected and should
Suggested initial settings for a patient new to NIPPV be tolerated if not interfering with patient comfort)
include an inspiratory positive airway pressure (IPAP) of (Fig. 3-10)
10 to 15 cm H2O, an expiratory positive airway pressure ● Adjust IPAP and EPAP levels as needed
(EPAP) of 3 to 5 cm H2O, and an FiO2 level titrated to
maintain SpO2 measurements greater than 95%. If these
settings are tolerated, IPAP can then be increased up to a Practicality
maximum of 20 cm H2O and EPAP to a maximum of 10 cm
H2O as needed to produce decreased dyspnea, decreased
● May avoid intubation
respiratory rate, and increased tidal volumes.11 Maximum
● Relatively inexpensive
IPAPs should be kept below 25 cm H2O as pressures below
● Easily and quickly initiated and discontinued
this level should not increase the risk of gastric distention.2
These initial settings are appropriate for most conditions
in which NIPPV has been shown effective. However, in
hypoxemic patients, some authors recommend using con- Indications
tinuous positive airway pressure (CPAP) at levels of 8 to
10 cm H2O over bilevel PAP.12 Additionally, in patients suf- ● COPD exacerbation
fering from cardiogenic pulmonary edema, NIPPV settings ● Congestive heart failure exacerbation
must be chosen with caution as there is some evidence ● Asthma exacerbation
that CPAP may be superior to bilevel PAP by resulting in ● Postextubation respiratory distress
a lower rate of myocardial infarction.13 ● “Do-not-intubate” status
● Restrictive thoracic disorders
● Obstructive sleep apnea
Preparation ● Idiopathic hypoventilation
● Select desired interface and size using sizing guide from

manufacturer
Contraindications
● Attach interface to ventilator
● Select desired IPAP, EPAP, and FiO2; an IPAP of 10 to
15 cm H2O and EPAP of 3 to 5 cm H2O with an FiO2 suffi-
● Respiratory arrest
cient to maintain SpO2 measurements above 95% are often
● Impaired respiratory drive
chosen as initial settings11
● Need for airway protection
● Assure flow of oxygen
● Hemodynamic instability
● Uncooperative patient
● Excessive secretions
Procedure ● Facial deformity
● Altered mental status impairing cooperation with machine
or resulting in impaired airway reflexes
● Place patient in an upright or semi-upright position
● Place interface onto patient and confirm sizing
● If the patient is using the interface for the first time, hold
it lightly to their face and allow them to breathe through Complications
it for a short period before applying head straps
● Tighten head straps so that one finger can be placed ● Ineffective ventilation
between the strap and the patient’s head ● Aspiration
● Observe the patient while they acclimate to NIPPV and ● Facial skin irritation and necrosis
watch for signs of clinical deterioration necessitating dis- ● Eye irritation
continuation of NIPPV ● Gastric insufflation
DESIGN SERVICES OF

FIG U RE 3-10 A: Example of an improperly

fitted oronasal mask with malpositioning of
the forehead support arm and insufficient
tension on the inferior straps resulting in an air
leak around the chin and mouth. B: Example
of an air leak around the nose from excessive
inferior strap tension and malpositioning of the
forehead support arm.
REFERENCES 4. Keenan SP, Sinuff T, Cook DJ, et al. Which patients with
acute exacerbation of chronic obstructive pulmonary dis-
1. Bach JR, Alba A, Bohatiuk J, et al. Mouth intermittent ease benefit from noninvasive positive-pressure ventilation?
positive pressure ventilation in the management of postpolio A systematic review of the literature. Ann Intern Med.
respiratory insufficiency. Chest. 1987;91(6):859–864. 2003;138(11):861–870.
2. Brochard I, Isabev D, Piquet J, et al. Reversal of acute 5. Masip J, Roque M, Sanchez B, et al. Noninvasive ventilation
exacerbations of chronic obstructive lung disease by respi- in acute cardiogenic pulmonary edema: systematic review
ratory assistance with a face mask. N Engl J Med. 1990;323: and meta-analysis. JAMA. 2005;294(24):3124–3130.
1523–1530. 6. Esteban A, Frutos-Vivar F, Ferguson ND, et al. Noninvasive
3. Gay P, Weaver T, Loube D, et al. Evaluation of positive air- positive-pressure ventilation for respiratory failure after
way pressure treatment for sleep related breathing disorders extubation. N Engl J Med. 2004;350(24):2452–2460.
in adults. Sleep. 2006;29(3):381–401.
DESIGN SERVICES OF

7. Burns KE, Adhikari NK, Keenan SP, et al. Use of non- 11. Pelosi P, Jaber S. Noninvasive respiratory support in the
invasive ventilation to wean critically ill adults off invasive perioperative period. Curr Opin Anaesthesiol. 2010;23(2):
ventilation: meta-analysis and systematic review. BMJ. 233–238.
2009;338:b1547. 12. Antonelli M, Conti G. Noninvasive positive pressure venti-
8. Levy M, Tanios MA, Nelson D, et al. Outcomes of patients lation as treatment for acute respiratory failure in critically
with do-not-intubate orders treated with noninvasive venti- ill patients. Crit Care. 2000;4(1):15–22.
lation. Crit Care Med. 2004;32(10):2002–2007. 13. Mehta S, Gregory DJ, Woolard RH, et al. Randomized
9. Soo Hoo GW. Ventilation, noninvasive. 2010. http://emedicine. prospective trial of bilevel versus continuous positive air-
medscape.com/article/304235. Accessed May 17, 2010. way pressure in acute pulmonary edema. Crit Care Med.
10. Pilbeam SP, Cairo JM, eds. Mechanical Ventilation: 1997;25(4):620–628.
Physiological and Clinical Applications. 4th ed. St. Louis,
MO: Mosby; 2006.
DESIGN SERVICES OF

CHAPTER
Retraction Blades
for Direct Laryngoscopy
4 cn
Dustin J. Jackson and Joseph F. Talarico
T he purpose of the laryngoscope is to retract the mandible

and soft tissues of the anterior oropharynx upward,
allowing visualization of the glottis. In cross section, the
Some variants of the Miller blade, such as the Phillips
(Fig. 4-1) or Wisconsin blade, have a higher vertical
profile, answering one of the deficiencies of the Miller
blade of the laryngoscope typically consists of a flat por- blade: inadequate space for ETT manipulation in the
tion (spatula) and a vertical portion (flange), along with pharynx despite an adequate view of the glottis. A vari-
a light source. These components are arrayed in a large ant of the Macintosh blade, the Bizzarri-Giuffrida blade,
variety of shapes and configurations to meet the challenge incorporates the curved design but eliminates the vertical
of elevating soft tissues during retraction and keeping flange, allowing insertion into small mouth openings or
them out of the line of sight of the laryngoscopist, while in patients with prominent or fragile teeth (Fig. 4-5). The
at the same time permitting the necessary manipulations McCoy blade is an articulating blade that allows the user
to insert an endotracheal tube (ETT). Since the origins of to lift its distal tip in order to improve the view of the
laryngoscopy in the late 19th century, laryngoscopes have glottis if the epiglottis remains downfolded and impedes
undergone an evolution in shape. Early versions had a “C” visibility.4 This blade has been compared with the stan-
shape configuration but did not have either detachable dard Macintosh blade, and it produced a better view in
blades or an intrinsic light source. By the middle of the almost 60% of patients in whom cords were not seen with
20th century, laryngoscopes incorporated with these inno- the Macintosh blade.5 When a grade 3 view was obtained
vations had been developed. More modern laryngoscopes with the McCoy blade in the neutral position, elevation
contain a light source in the handle with fiberoptic bundles of the tip significantly improved visualization; but when
in the blades. The older-style laryngoscopes remain in use a grade 1 or 2 view was obtained with the blade in the
by ear-nose-throat (ENT) surgeons today for diagnostic neutral position, elevation of the tip worsened the view
and therapeutic procedures involving the airway. in 23% of patients.6 The McCoy levering laryngoscope
Many different types of retraction blades for direct blade is marketed as the “Flipper” (Rusch, Inc. Research
laryngoscopy are available today. Although many varia- Triangle Park, NC) and also as the “Flex Tip” (Heine USA,
tions of the straight and curved blade exist, the Miller and Dover, NH).
Macintosh blades, introduced in the 1940s, remain the Other designs include the Choi blade, which is a dou-
most commonly used blades in clinical practice (Figs. 4-1 ble-angle blade that combines features of both the straight
and 4-2).1,2 Conventionally, the straight blade is inserted and curved laryngoscope blades (Fig. 4-6). This may be of
beneath the epiglottis and is used to directly lift it, expos- benefit in patients with an anterior glottis, a large tongue
ing the glottis (Fig. 4-3). The curved blade, on the other or “floppy” epiglottis, and also in patients with promi-
hand, fits into the vallecula, exerting upward traction on nent upper incisors, owing to its lack of vertical flange.7
the glossoepiglottic ligament as it is lifted, thereby indi- The “Improved View Macintosh” blade allows for an en-
rectly raising the epiglottis superiorly and allowing the hanced view of the larynx because of a concavity in the
operator to visualize the exposed glottis (Fig. 4-4). The flat portion of the blade (Fig. 4-7).8 A new curved blade
choice of laryngoscope blade is largely based on the per- has been described by Nishikawa, which has an S-shaped
sonal preference of the operator, with both Macintosh and spatula and bifid tip designed to prevent posteroinferior
Miller blades being a reasonable choice for a “normal” air- displacement of the compressed tongue, thereby allowing
way. In general, the advantages of the Macintosh blade better laryngeal views in patients with a large or promi-
include more room for passage of the ETT, whereas the nent tongue (Fig. 4-8).9 Blades that incorporate mirrors or
Miller blade may provide better visualization in patients prisms to aid in direct laryngoscopy also exist, and these
with a small mandibular space, large incisor teeth, or a will be discussed further in Chapter 16. Table 4-1 details
large epiglottis (see also Chapter 5).3
29

F I GUR E 4 -1 Two sizes of Miller laryngoscope

blades and Phillips (bottom left) blade.
F I GUR E 4 -2 Two sizes of Macintosh laryngo-

scope blades.

CHAPTER 4 ■ RETRACTION BLADES FOR DIRECT LARYNGOSCOPY 31
FIG U RE 4-3 Miller blade shown

directly lifting epiglottis.
FIG U RE 4-4 Macintosh blade

shown with tip in vallecula.

F I GUR E 4 -5 Bizzarri-Giuffrida laryngoscope

blade. No vertical flange is present to allow
insertion into a small oral cavity or for those
patients who cannot open the mouth well.
F I GUR E 4 -6 Choi laryngoscope blade. No

vertical flange and double-angle design, for
patients with an anterior glottis, large tongue,
floppy epiglottis, or prominent teeth.
F I GUR E 4 -7 “Improved View” Macintosh

laryngoscope blade. This blade contains a
concavity in the flat portion or “spoon” of the
blade, permitting a better view of the glottis.

CHAPTER 4 ■ RETRACTION BLADES FOR DIRECT LARYNGOSCOPY 33
FIG U RE 4-8 Nishikawa laryngoscope blade.

This blade has an S-shaped spatula and bifid tip,
designed to manage the bulk of a large tongue.
(From Nishikawa K, Yamada K, Sakamoto A.
A new curved laryngoscope blade for routine
and difficult tracheal intubation. Anesth Analg.
2008;107:1248–1252 with permission.)
Table 4-1
Selected Retraction Blades
Blade Characteristics Uses/Advantages

Straight Blades
Miller Straight blade with curved tip Normal airway, long epiglottis, “deep”
glottis, prominent upper incisors
Phillips and Wisconsin Straight blade with higher vertical More room for ETT placement
profiles than Miller than Miller
Curved Blades
Macintosh Curved blade Normal airway
Bizzarri-Giuffrida Curved blade with no vertical flange Small mouth opening or protruding
or fragile teeth
McCoy Curved blade with adjustable, Facilitates lifting of epiglottis
articulating tip
Choi Double-angle blade Anterior glottis, large tongue, floppy
epiglottis, prominent teeth
Improved-view Concavity in long axis Better view of anterior
Macintosh of spatula glottis
Nishikawa Curved S-shaped blade Prevents posteroinferior displacement
of compressed tongue
Siker Incorporates mirror into blade Anterior glottis
Belscope Angulated, optional prism attachment Anterior glottis or normal airway

characteristics and advantages of the most common blades 4. McCoy ED, Mirakhur RK. The levering laryngoscope.
as well as some less common ones. Anaesthesia. 1993;48:516–518.
Some common laryngoscope blades have been incor- 5. Cook TM, Tuckey JP. A comparison between the MacIntosh
porated into video laryngoscope systems (see Chapter 24) and McCoy laryngoscope blades. Anaesthesia. 1996;51:
977–980.
and thus lend themselves to conventional direct laryngos-
6. Tuckey JP, Cook TM. An evaluation of the levering laryngo-
copy, as well as use of the video screen for visualization of
scope. Anaesthesia. 1996;51:71–73.
the glottis and ETT placement. Such tools are also quite 7. Choi JJ. An angulated laryngoscope for routine and difficult
useful for teaching direct laryngoscopy, because the in- tracheal intubation. Anesthesiology. 1990;72:576.
structor, while viewing the screen, is able to appreciate a 8. Racz GB. Improved vision modification of the MacIntosh
direct laryngscopy view quite similar to that of the trainee. laryngoscope (letter). Anaesthesia. 1984;39:1249.
The DCI video system (Karl Storz Endoscopy-America, 9. Nishikawa K, Yamada K, Sakamoto A. A new curved laryn-
El Segundo, CA) is one such example, with an ergonomi- goscope blade for routine and difficult tracheal intubation.
cally designed handle, which houses the camera, to which Anesth Analg. 2008;107:1248–1252.
is affixed one of several different standard-shape laryngos-
copy blades. These include Macintosh size 2-4, Miller size
0-4, and the Dorges “hybrid” blade, which has features of
both the Macintosh and the Miller blades.
REFERENCES
1. Miller RA. A new laryngoscope. Anesthesiology. 1941;1:
317–319.
2. Macintosh RR. A new laryngoscope. Lancet. 1943;1:205.
3. Barash PG, Cullen BF, Stoelting RK, et al. Clinical Anesthesia.
6th ed. Philadelphia, PA: Lippincott Williams & Wilkins;
2007:765.

CHAPTER
Direct Laryngoscopy 5 cn
James Snyder and Steve Orebaugh
CONCEPT EVIDENCE
When face mask ventilation is inadequate to provide On the other hand, various factors weigh toward optimiz-
necessary airway support, or when long-term positive ing conditions to ensure “first pass success.” Preparation
pressure ventilation is required, an endotracheal tube for successful intubation on the first attempt is indicated by
(ETT) should be placed. In most circumstances, direct la- urgency, anatomic predictors of difficulty (see Chapter 9),
ryngoscopy (DL) is the simplest and most readily applied cardiopulmonary instability, a likely full stomach, possi-
means of placing the ETT. Indications for DL and endotra- ble gastric insufflation by first responders in codes, overly
cheal intubation are summarized below (Table 5-1). large body habitus, and (especially) limited operator
experience.
Table 5-1 KEYS TO “FIRST PASS SUCCESS”

Indications for Tracheal Intubation
The case for first pass success has been well summarized
Indication Example by Levitan.1 In emergent or unplanned situations requiring
intubation, maneuvers to cope with unpredicted difficulty
Airway patency Unconscious patient are planned into the approach rather than added sequentially
Airway protection Patient at risk as might occur in a conventional approach. Once familiar
for aspiration with the maneuvers that maximize first pass success, the
Oxygenation failure Pneumonia operator may choose a simpler approach. Keys to first pass
with hypoxemia success include (1) manipulation of the axial anatomy
Ventilation failure Severe asthma (ie, head, neck, torso positioning) to achieve optimal rather
with respiratory failure than adequate glottal exposure, (2) retention of fine motor
control, through the use of assistants or physical supports
Management of secretions Copious sputum from
for optimal position of the upper torso and head/neck,
pneumonitis
(3) effective navigation to find and control the epiglot-
Provision of hyperventilation Increased tis, and (4) early use of bimanual laryngoscopy. Each key
intracranial pressure requires practice until it is automated. Integrated perfor-
Drug administration Inability to secure mance to complete intubation within 30 seconds, as rec-
intravenous access ommended for unstable patients, requires more practice.
Muscle paralysis for surgery Intra-abdominal
and intrathoracic PREPARATION FOR LARYNGOSCOPY
surgery
Careful preparation for intubation requires a mental check-
list. Of many helpful pneumonic devices, the authors pre-
fer “STOP MAID,” to remember the following (Fig. 5-1):
When difficulty is unlikely and when conditions are S: Suction
optimized prior to the attempt at intubation (for instance, T: Tools for intubation (laryngoscope blades, handle)
during elective cases in the operating room), the standard and for difficulty with ventilation and/or intubation
sniffing position is an efficient starting position for expe- (laryngeal mask airway [LMA], intubating LMA, light-
rienced practitioners to intubate unassisted. wand, optical stylet, etc.)
35

F IG U R E 5 -1 Intubation equipment.
O: Oxygen source for preoxygenation and ongoing venti- Axial Positioning During Blade Insertion
lation Experienced operators typically can expose the glottis
P: Positioning—shoulder roll and head elevation as high with no or minimal elevation of the patient’s head and
as it does not interfere with blade insertion; PLAN B: torso from the sniffing position and usually require
Effective airway management requires careful plan- no assistance to improve glottic view even when com-
ning so that back up plans can be executed when the plex manipulations are necessary. For less experienced
primary technique (plan A) fails.2 operators and when patient instability demands first pass
M: Monitors, including EKG, pulse oxymetry, blood success, head lift by an assistant from the initiation of DL
pressure, end-tidal CO2, or esophageal detectors requires less left hand force, improves sensitivity and con-
A: Assistant, ambu bag with face mask, airway devices trol, and frees the right hand for external manipulation. As
(tubes, syringe, stylets) described by Murphy: “. . . the sniffing position is a start-
I: Intravenous access ing position only . . . make it dynamic. Use your right hand
D: Drugs including hypnotic, muscle relaxant and desired behind the head to lift it, flex and extend the head on the
adjuncts neck, rotate it left and right as needed to bring the target
Effective airway management requires careful planning into view. Once the best view is obtained, have an assistant
so that back up plans can be executed when the primary hold the head in this position.”7
technique fails
Opening the Mouth
The mouth is opened widely by supporting the index, long,
POSITIONING and/or ring fingers of the right hand against the upper
teeth, and crossing the thumb down against the lower
Positioning can facilitate both blade insertion and glot- teeth (Fig. 5-5). Atlanto-occipital extension, provided
tic exposure. The sniffing position, most clearly defined by placing the right hand against the occiput of the un-
by Horton et al3 is atlanto-occipital extension, and eleva- conscious patient, can help to open the mouth as well.
tion of the head to achieve “lower neck flexion [of] 35˚,” Mouth opening and/or blade insertion may be compro-
which in normal volunteers required head support of 31 to mised by retrognathism, prominent upper teeth, obesity,
71 mm. Further head elevation may facilitate DL and may large breasts, short thick neck, or neck flexion. Elevation
be essential for intubation in difficult cases.2–7 Clinical and of the upper thorax as by a shoulder roll, or creation of a
geometric observations show flexing the thoracic spine to “ramp,” can facilitate mouth opening and blade insertion
elevate the head may facilitate DL more than flexion of the by improving submandibular compliance and increasing
cervical spine (Figs. 5-2–5-4). physical separation of the chin from the chest (Figs. 5-2–5-4
DESIGN SERVICES OF

CHAPTER 5 ■ DIRECT LARYNGOSCOPY 37
FIG U RE 5-2 When a normal heavy-set indi-

vidual opens his mouth the submandibular and
anterior cervical spaces impinge (despite, in this
example, head elevation of 5 cm). As a result,
submandibular compliance is decreased (com-
pare A and B). C. Impingement is made worse
when head elevation is achieved by cervical
flexion, especially in patients with a short neck
or who are heavy-set. D. Flexion of the thoracic
spine enables a higher head elevation relative to
the chest while decreasing impingement. (Table
level is the same in all photos.)
FIG U RE 5-3 Value of ramp construction to

facilitate blade insertion and glottic exposure
is best documented in care of morbidly obese
patients1,8. Levitan added the bar to promote
elevation of the head to align the ear canal
with the sternal notch. Elevation of the ear
can be achieved by flexion of the neck or the
chest. Geometric considerations are helpful to
understand why thoracic flexion is more
helpful (Fig. 5-4).
(Modified from Levitan et al with permission.)
and Fig. 5-6). Simply rotating the blade for insertion, then Curved Blade Technique
turning it into the correct plane, may be helpful, with Easy exposure in some cases may tempt the operator to
care that rotation not result in torque pressure against the casually insert the blade first and correct its position only
teeth. A short-handled laryngoscope may also be useful in if necessary. A safer practice is habitual early and contin-
these settings. ued sighting of the epiglottis until the tip of the curved
Novices are well advised to advance the blade over blade is passed above it. The epiglottis is the essential
the right dorsum of the tongue, sufficiently close to the landmark for both curved blade and straight blade laryn-
midline to retain orientation. Insertion along the right goscopy. A more lateral approach from the right side can
side of the mouth allows the vertical flange of the blade lower the angle “under” the tongue; contact of the flange
to cordon most of the tongue to the left (Fig. 5-7). When with teeth is diminished by first maximally opening the
the glottis is sighted, if there remains a residual bulge of mouth.
tongue on the right of the blade, pulling the right corner Optimal position of the curved blade tip on the
of the mouth laterally usually allows the glottis to remain hyoepiglottic ligament is defined by briskness of epiglottis
in sight while the tube is passed below (cephalad to) the response to light forward movement of the blade tip, or
tongue mass. external pressure by the fingers of the right hand on the
Utility of Bimanual Laryngoscopy/ thyroid cartilage. It is helpful to have a mental image of
External Laryngeal Manipulation the several blade tip positions that cause inadequate epi-
glottis response (see Fig. 10, in Anatomy chapter). During
Wilson and colleagues9 were the first to quantify the
elective laryngoscopy in stable patients, the use of gentle
value of laryngeal pressure when they used it to reduce
bimanual laryngoscopy to learn how different blade posi-
the incidence of grade 3 and 4 views from 9.3% to 5.9%.
tions affect the epiglottis and how to navigate to the “sweet
Benumof and Cooper10 found that the technique, which
spot” is a useful exercise.
they called optimal external laryngeal manipulation, could
consistently improve the laryngeal view by one Cormack-
Lehane grade. Levitan11 further reinforced the utility of Lifting Vector
this technique, referring to it as bimanual laryngoscopy. The blade angle is almost vertical during initial inser-
External laryngeal manipulation should be an integral part tion into the mouth, then it is swung forward to lift
of DL and should be the first maneuver used to improve the tongue (Fig. 5-9). It is important to avoid levering
the view of the larynx (Fig. 5-8A–D). back, as may seem tempting, to see “under” the tongue
DESIGN SERVICES OF

F I GUR E 5-4 Effect of axial manipulation on T5-6

Arrows show direction of movement
glottic exposure: Atlanto-occipital (a-o) extension, T1-2
from flexion at the level indicated
and cervical vs. thoracic flexion. C5-6
C2-3
A-o extension (indicated by red upper and lower Chin-chest impingement
incisors) facilitates DL by several mechanisms. T5-6 decreases with thoracic and
1. Reduced tissue impingement allows the mouth T1-2 lower cervical flexion
but
to open maximally and improves compliance of C5-6 increases with mid- and upper
the submandibular space. 2. Blade insertion is C2-3 cervical flexion
facilitated by moving the mouth away from the
C2-3
chest. 3. Flexion at every level is more effective
C5-6
because flexion arcs are rotated upward. 4. The
T1-2
upper spine is elevated, which requires spine T3-4
flexion. The spine is elevated because the distance T5-6
between the a-o rotation center (black dot) and A-O extension allows the mouth to open fully (from ~ 4 cm to 6 cm) and rotates
table surface is increased (black and red lines); this the point of contact with the table to a point further from the rotation center
elevation of the spine requires spine flexion just as (black dot). This elevates the rotation center (from the black to the red dot), which
does elevation on a pillow. requires the spine to flex.
Level of flexion. The effect of head elevation on

DL depends on the level at which flexion occurs:
Head elevation requires flexion of the spine, which
can occur anywhere from C2-3 to the lumbar
spine. Geometric considerations suggest that
whether submandibular compliance improves or is
made worse depends on where flexion occurs. The
black figure indicates the spine in a neutral posi-
tion; mouth opening is limited by impingement
of submandibular and anterior cervical tissues.
Arrows arcing from the chin indicate movement
due to flexion at the levels indicated. Flexion of
the C spine (C2-3 - C5-C6) increases impingement
below the chin and causes the trachea to slide into
the thoracic inlet. The tissue beds are increasingly
separated by flexion lower in the spine, due to
greater radius as well as more vertical arc.
(Fig. 5-10). Resistance to soft tissue displacement as As with the curved blade, the epiglottis is identi-
upward force is applied is best addressed by lifting fied in the straight blade technique and secured in a
the head, which is accompanied by a rotation forward controlled, deliberate manner. Exposing the glottis
of the lift vector and often an improved view of the accidentally after inserting the blade to the presumed
glottis.3-7 correct depth may lead to blind probing and should be
discouraged. The narrow tip of the Miller blade readily
Straight Blade Technique penetrates the posterior hypopharynx, and the trauma
A no. 2 Miller blade is adequate for most adults.12 The may not be apparent in many cases until manifested as
essence of straight blade laryngoscopy is to place the blade deep neck infection or sepsis.13 In addition, if the larynx
tip underneath the epiglottis, then lift it to reveal the glot- is inadvertently bypassed, retraction with the laryngo-
tis. The tip of the blade may thus be advanced into the scope may reveal the orifice of the proximal esopha-
superior-most portion of the laryngeal inlet before retrac- gus, which can appear deceptively “airway-like” (see
tion actually begins. Fig. 5-11).
DESIGN SERVICES OF

A B
F I GUR E 5 -5 A : Mouth opening using fingers in a “scissors” configuration. B: Mouth opening using head extension.
FIG U RE 5-6 For obese patients, a “ramp”

of blankets, or commercially available foam
wedge, allows the patient to more effectively
adopt a “sniffing” position, enabling laryngo-
scope blade insertion and effective DL.
FIG U RE 5-7 Sweeping tongue to left with

laryngoscope blade.
DESIGN SERVICES OF

A B
C D
F I GUR E 5 -8 A: External laryngeal pressure by operator. B: Assistant taking over ELM from operator. C: View of glottis without
external laryngeal pressure. D: View of glottis with external laryngeal pressure.
F I GUR E 5 -9 Direction of forces applied for DL.
DESIGN SERVICES OF

FIG U RE 5-10 Inappropriate “levering” force

in DL. Note pressure of flange of Macintosh
blade against upper lip and teeth.
FIG U RE 5-11 Glottis-like appearance of esophageal opening when blade is

passed below and lifts larynx. Mucosal folds cam be mistaken for posterior car-
tilages, a fold of mucosa can simulate a vocal cord or aryepiglottic fold, and a
pool superior to the orifice can be mistaken for a pool obscuring the opening
to the esophagus.
Straight blade lift vectors are similar to those of curved the Macintosh blade. Achen15 noted that the paraglossal
blade laryngoscopy. After initial near-vertical insertion, technique with the Miller blade provided a higher propor-
the handle and angle are lowered to pass under the tongue, tion of full laryngeal exposure than the Macintosh blade
and may be lowered further as the blade is advanced; but among 160 anesthetized patients. The low vertical profile
the temptation to lever back on the laryngoscope blade and narrow spatula of the Miller blade can be particularly
must be avoided. Difficulty with soft tissue displacement useful in this relatively cramped region of the oral cavity.
should be addressed by lifting the head, which rotates When mouth opening admits a higher flange, there are
the lift vector forward and often improves the view of advantages to the Phillips and Henderson blade designs
the glottis, as noted in the section on curved blade tech- (Figs. 5-12 and 5-13).
nique. Also as with the curved blade, midline insertion When an appropriate view of the larynx is established,
of the straight blade facilitates orientation, but glottic the ETT is placed, inserting it from the right side of the
exposure in difficult cases benefits from a more lateral mouth, with as little interference of the line of sight as pos-
right-sided, or “paraglossal,” approach. sible. The lips often are more of an impediment to the ex-
Henderson14 reviewed the paraglossal technique treme rightward approach than in a more midline approach,
and described successful use of the Miller blade in or in curved blade laryngoscopy, and use of an assistant to
10 patients in whom the view of the glottis was poor with retract the lip permits easier insertion of the tube.
DESIGN SERVICES OF

A B C
D E F
F I GUR E 5 -1 2 Paraglossal straight blade approach. Tongue control and gutter entry is initiated by crossing from the left to
enter the right gutter (B, C, D), then advancing only to the right anterior pillar. Pharyngeal landmarks are sought by rotating the
blade tip to the left (E). The blade tip is advanced under the epiglottis and lifted to expose the glottis, then the blade is moved
toward the midline to displace the tongue and make room for the ET (F).
(Borland, personal communication.)
A B
F I GUR E 5 -1 3 Paraglossal laryngoscopy (Phillips blade): “Advance to anterior pillar and look left.” The glistening sharp edge on
the right (A: between 3 and 5 o’clock) is the right anterior tonsillar pillar. Placement of the uvula at 6 to 9 o’clock and follicular
tongue to the left accentuates this blade coming in from the gutter on the right side of the tongue. Bulb position on the left side
of this no. 1 Phillips blade helps avoid crowding in this technique and catching or ripping the ET or cuff. In this pediatric patient
the blade tip is anterior to the epiglottis, as commonly is effective in children but not adults.
(Navigation and figure courtesy of L. Borland.)
Straight Blade versus Curved Blade allows a lower angle of approach. Straight blades are rec-
A lateral approach is required for difficult cases with either ommended to reduce trauma to friable pathology at the
blade. A smaller viewing port (Miller blade) and reduced base of the tongue, such as hypertrophic lingual tonsils.16
area in which to manipulate the tube (far right corner or Comparison studies have indicated straight blade success
paraglottic approach), can make tube insertion with the after curved blade failure; we are not aware of the opposite
straight blade more challenging than with an adequate finding.14,15
curved-blade laryngoscopic view. However, straight The amount of lifting force required to expose the
blades require less anterior displacement of the hyoid glottis maximally is related to some known variables:
bone for a given line of sight, and the paraglossal approach the heavier the patient, the greater is the force required,
DESIGN SERVICES OF

use bag mask ventilation (see Chapter 2) to achieve the

highest possible oxygenation between every attempt at
laryngoscopy.
During intubation, as the tube is advanced into the
mouth and pharynx, every attempt must be made to avoid
placing it into the operator’s line of sight. Rather, the tube
should enter the mouth lateral to the blade, and pass close
to the palate below the line of sight, then manipulated so
the tip appears from below at the glottic opening.
Emergent intubations should be carried out with a
stylet in place in the ETT. Once the tip of the tube has
passed the vocal cords, the stylet may contribute to tra-
cheal damage. At this point, the laryngoscopist should
hold the ETT firmly and keep the laryngoscope in place,
observing that the tube is not dislodged, as an assistant
removes the stylet. Although the angle to which the ETT-
stylet combination is bent is an individualized decision,
it has been shown that an angle of less than 35° seems to
facilitate passage of the ETT beyond the glottis.7
F I GUR E 5 -1 4 ETT insertion.
and the lifting force required is less with a straight blade REFERENCES
than with a curved one.17,18 Hastings et al18 evaluated force 1. Levitan RM. The Airway Cam Guide to Intubation and
required for laryngeal exposure with a size 2 Miller blade Practical Emergency Airway Management. Wayne, PA:
and a size 3 Macintosh blade in 17 patients, and found that Airway cam Technologies, inc.; 2004.
the Miller blade required 30% less lifting force; the view 2. Hochman II, Zeitels SM, Heaton JT. Analysis of forces and
was similar with both blades in 10 patients, whereas it position for direct laryngoscopic exposure of the anterior
favored the curved blade in three patients and the straight vocal folds. Ann Otol Rhinol Laryngol. 1999;108:715–724.
blade in four. 3. Horton WA, Fahy L, Charters P. Defining a standard intubat-
ing position using “angle finder.” Br J Anaesth. 1989;62:6–12.
Despite these possible advantages of a straight
4. Schmidt HJ, Mang H. Head and neck elevation beyond
laryngoscope blade, most physicians prefer to initiate the sniffing position improves laryngeal view in cases
laryngoscopy with the curved blade. Its larger spatula of difficult direct laryngoscopy. J Clin Anesth. 2002;14:
permits greater area for both viewing and manipulation of 361–365.
the tube, as does its vertical flange. The “feel” of a curved 5. Levitan R, Mechem CC, Ochroch EA, et al. Head elevated
blade is more anatomic as it curves along the tongue laryngoscopy position: improving laryngeal exposure dur-
and seats in the vallecula. Frequent departure from this ing laryngoscopy by increasing head elevation. Ann Emerg
comfort zone is recommended to maintain skill with an Med. 2003;41:322–330.
alternative straight blade. 6. Jackson C. Bronchoscopy, Esophagoscopy and Gastroscopy.
Philadelphia, PA: W.B. Saunders; 1934.
7. Murphy MF, Hung OR, Law JA. Tracheal intubation: tricks
of the trade. Emerg Med Clin North Am. 2008;26:1001–1014.
ETT PLACEMENT 8. Collins JS, Lemmens HJ, Brodsky JB, Brock-Utne JG,
Levitan RM. “http://www.ncbi.nlm.nih.gov/pubmed/15527629”
Once the glottic view is revealed, and found to be ad- Laryngoscopy and morbid obesity: a comparison of
equate, the ETT is placed between the vocal cords with the “sniff” and “ramped” positions. Obes Surg. 2004
the right hand (Fig. 5-14). Attempts at laryngoscopy may Oct;14(9):1171–5.
become quite involving, and the laryngoscopist may easily 9. Wilson ME, Spiegelhalter D, Robertson JA, et al. Predicting
lose track of the duration of patient apnea. Laryngoscopy difficult intubation. Br J Anaesth. 1988;61:211–216.
10. Benumof JL, Cooper SD. Qualitative improvement in laryn-
attempts should generally be limited to 30 seconds,
goscopic view by optimal external laryngeal manipulation.
or the occurrence of oxygen desaturation, whichever J Clin Anesth. 1996;8:136–140.
comes first. Note that SpO2 technology results in at least 11. Levitan RM, Kinkle WC, Levin WJ, Everett WW. Laryngeal
30 seconds delay in readout. Particularly in critically ill view during laryngoscopy: a randomized trial comparing
patients, rapid desaturation may occur due to inadequate cricoid pressure, backward-upward-rightward pressure,
time for preoxygenation, atelectasis with shunting, or and bimanual laryngoscopy. Ann Emerg Med. 2006;47(6):
cardiopulmonary pathology. Thus it is imperative to 548–55.
DESIGN SERVICES OF

12. Magill RA. The development of the laryngoscope. compared to that with the Macintosh blade. Anaesth Int
Anaesthetist. 1972;21:145–147. Care. 2008;36:717–721.
13. Caplan RA, Posner KL, Ward RJ, Cheney FW. Adverse 16. Al Shamaa M, Jefferson P, Ball DR. Lingual tonsillar
respiratory events in anesthesia: a closed claims analysis. hypertrophy: airway management using straight blade
Anesthesiology. 1990;72:828–33 direct laryngoscopy. Anesth Analg. 2004;98:874–875.
14. Henderson JJ. The use of paraglossal straight blade 17. Bishop MJ, Harrington RM, Tencer AF. Force applied during
laryngoscopy in difficult tracheal intubation. Anaesthesia. tracheal intubation. Anesth Analg. 1992;74:411–414.
1997;52:552–560. 18. Hastings RH, Hon ED, Nghiem C, et al. Force and torque
15. Achen B, Terblanche OC, Finucane BT. View of the larynx vary between laryngoscopists and laryngoscopy blades.
obtained using the Miller blade and paraglossal approach Anesth Analg. 1996;82:462–468.
DESIGN SERVICES OF

CHAPTER
Confirmation of Endotracheal
Tube Placement
6 cn
Brian Blasiole and Tetsuro Sakai
A misplaced endotracheal tube (ETT) can result in

severe morbidity and mortality. As soon as an ETT
is inserted, its presence in the trachea must be confirmed.
and contains a column of air, a collapsed bulb device
attached to the proximal end of an ETT that is in the
airway should suction air and be rapidly reinflated. On
A quick method to confirm ETT placement is to directly the other hand, if an ETT is placed in the esophagus,
visualize the ETT as it passes through the vocal cords. the deflated bulb device remains collapsed because the
Video laryngoscopes have improved the approach of vi- negative pressure generated by the device apposes the
sualizing the airway (Fig. 6-1A, B)1; however, a view of esophageal walls.4
the glottis may often be obscured despite the technique of Physical examination should always be performed in
visualization used. As no single test exists that definitely conjunction with the above methods for the confirmation
establishes correct placement of the ETT, confirmation of an ETT placement (Figs. 6-4 and 6-5). These include
should best be carried out with a combination of physical auscultation of chest (which is best carried out in the bi-
examination maneuvers and CO2 detection. lateral axillae) (Fig. 6-5) and upper abdomen (appreciat-
Detection of exhaled CO2 is widely accepted as the ing sounds of gastric insufflation), as well as observation
most reliable, readily available technique of confirming for evidence of chest rise and the absence of gastric dis-
ETT placement. This is accomplished either with capno- tension. Additional physical signs of appropriate tracheal
graphy (continuous monitoring of end-tidal CO2, which is intubation include the appearance of vapor in the ETT
displayed graphically on a dedicated monitor) (Fig. 6-2A) during exhalation and “balloting” of the ETT cuff above
in operating rooms or with a small, portable end-tidal the sternal notch while palpating the pilot balloon of the
CO2 detector (a purple-to-yellow color change indicates ETT (Fig. 6-4).5 None of these methods is entirely reliable,
presence of >4% CO2 in exhaled gases) (Fig. 6-2B, C) but in combination with CO2 detection (or the esophageal
outside of operating rooms. Although CO2 detection reli- bulb detector, if CO2 is not likely to be present), these
ably localizes the ETT in the airway, it does not distin- physical examination maneuvers should nearly eliminate
guish between tracheal and endobronchial intubations. the possibility of esophageal intubation.
Furthermore, both false-negative and false-positive results Several imaging modalities can be used for further
may occur.2 Even with correct ETT placement, exhaled confirmation of ETT placement. Postintubation chest ra-
CO2 will be near 0 in patients with severe bronchospasm, diography can contribute to ETT localization. Anterior-
cardiac arrest, or markedly diminished pulmonary blood posterior X-ray can be used as a tool to estimate the
flow despite correct placement of the ETT. Other confir- depth of ETT insertion and to rule out bronchial intu-
mation methods are preferred in these situations. It should bation. However, the lateral film is more reliable in de-
be noted that, during esophageal intubation, CO2 can be tecting esophageal intubation because superimposition of
detected from gases present in the stomach or esophagus. an esophageal ETT over the trachea can be misleading.
Detection of such CO2 usually rapidly diminishes over Although frequently unavailable outside of the operat-
four to five attempts at ventilation. If end-tidal CO2 is de- ing room or critical care unit, fiberoptic bronchoscopy
tectable and stable (not diminishing) thereafter, the ETT is a highly accurate method to ascertain correct ETT
is almost certainly in the airway.3 position6 as it provides direct visualization of the ETT
When no means of CO2 detection is available or CO2 and its location. Ultrasonography is a newer method to
detection is unreliable (ie, cardiac arrest), the esophageal determine ETT position. It can provide direct visualiza-
bulb detector device can provide a means to ascertain tion of a styletted ETT during placement in the trachea.7
whether the ETT is in the airway or in the esophagus Transthoracic ultrasonographic imaging of diaphragmatic
for patients older than 1 year of age (Fig. 6-3A, B). As and pleural motion with lung expansion can provide indi-
the trachea (and bronchi) possesses cartilaginous walls rect evidence of correct ETT position.7
45

F I GUR E 6 -1 GlideScope Video Laryngoscope

(GVL; Verathon, Bothell, WA, USA).
A: Anesthetist visualizing the glottis using the
GVL. B: View of the glottis using the GVL.

CHAPTER 6 ■ CONFIRMATION OF ENDOTRACHEAL TUBE PLACEMENT 47
FIG U RE 6-2 A: Capnography in the operating

room. B: CO2 color-change indicator: purple color
before connection to circuit. C: The indicator turns
yellow when connected to the circuit, indicating
correct ETT placement.

F I GUR E 6 -3 A: An esophageal bulb detector

device. B: When placed on the end of the ETT,
and deflated, it should reinflate if the ETT is in the
trachea.
F I GUR E 6 -4 “Balloting” the ETT cuff in the

trachea while palpating the pilot tube.

CHAPTER 6 ■ CONFIRMATION OF ENDOTRACHEAL TUBE PLACEMENT 49
FIG U RE 6-5 Auscultation in the axillary area

contributes to confirmation of ETT placement.
REFERENCES level in emergency intubation. Ann Emerg Med. 1996;27:

595–599.
1. McElwain J, Malik MA, Harte BH, et al. Comparison of the 5. Salem MR, Baraka A. Confirmation of tracheal intubation.
C-MAC videolaryngoscope with the Macintosh, Glidescope, In: Benumof JL, ed. Airway Management, Principles and
and Airtraq laryngoscopes in easy and difficult laryngos- Practice. St. Louis, MO: Mosby; 1996:531–560.
copy scenarios in manikins. Anaesthesia. 2010;65:483–489. 6. Benumof JL. Management of the difficult airway: with spe-
2. Salem MR. Verification of endotracheal tube position. cial emphasis on awake tracheal intubation. Anesthesiology.
Anesthesiol Clin North America. 2001;19:813–839. 1991;75:1087–1110.
3. Birmingham PK, Cheney FW, Ward RJ. Esophageal intu- 7. Rudraraju P, Eisen LA. Confirmation of endotracheal
bation: a review of detection techniques. Anesth Analg. tube position: a narrative review. J Intensive Care Med.
1986;65:886–896. 2009;24:283–292.
4. Bozeman WP, Hexter D, Liang HK, et al. Esophageal de-
tector device versus detection of end-tidal carbon dioxide

CHAPTER
7 Pharmacology for Airway

Management
Daniel Cormican and Shawn Beaman
M edications are used in most airway management

situations, and as such, familiarity with the com-
mon drugs and dosages used is crucially important. The
a brief duration of action. In cases where succinylcholine
is contraindicated or avoidance of its side effects is desired
(Table 7-4), a nondepolarizing neuromuscular blocker
basic premise of medication use in airway management is such as rocuronium or vecuronium is often used.3 It
to create optimal conditions for the requisite airway inter- should be noted that neuromuscular blockade is not al-
vention while maintaining the patient’s safety. Different ways used in preparation for perioperative airway man-
airway situations require different medications and opti- agement—such medication is not used during any awake
mization can have various forms, which always include airway management interventions because continued
maintaining oxygenation, maintaining hemodynamic sta- spontaneous respiration is desired, and avoiding use of
bility, and blunting the sympathetic response to the airway neuromuscular blockade may be appropriate in certain
intervention. Other goals include keeping the patient as cases where overall patient outcome might be jeopardized
comfortable as possible and relaxing skeletal muscle when with its use (eg, procedures where motor function is to be
appropriate. Pharmacologic intervention prior to airway monitored or patients with myasthenia gravis).4
management should be tailored to the specific needs and As with adults, optimal airway conditions are sought
current clinical conditions of each patient. Inappropriate in children undergoing surgery (see Chapter 40). This is
use of many of the medications mentioned in this chapter frequently carried out not with IV medications but rather
can actually cause the patient harm. with inhalational anesthetic gases. Sevoflurane is the most
In controlled, elective airway management commonly used agent for inhaled induction of anesthesia
situations—for example, placement of endotracheal tube because of its rapid onset and comparatively less pungent
for elective surgery—the first medication administered and irritating characteristics. In either adult or pediatric
is often an anxiolytic and/or analgesic (Table 7-1).1 This patients, it is important to be mindful of the expected al-
helps decrease the anxiety and fear commonly reported terations in hemodynamics and respiration after adminis-
before surgical procedures. Oxygen is then provided to tration of sedatives, analgesics, and general anesthetics.5
help maintain necessary blood oxygen content for homeo- Emergent airway management situations may require
stasis during the expected period of apnea that occurs af- different medications from those used in elective cases. In
ter administration of intravenous (IV) general anesthetic situations requiring emergent intubation of a conscious
agents (Table 7-2) and muscle relaxants (Table 7-3), patient, IV hypnotics are routinely administered to render
which are provided to render a patient unconscious and a patient unconscious, as they are in a controlled elective
paralyzed, respectively, for the planned airway interven- situation. However, attention must be paid to the over-
tion. Note that the anesthetic must be administered before all presentation of the patient requiring immediate airway
the muscle relaxant so as to avoid the patient experiencing intervention. In hemodynamically stable patients with
total paralysis while awake. The combination of anesthe- presumed euvolemia, both propofol and sodium thiopen-
sia and paralysis serves an important role in optimization tal can be utilized to provide rapid loss of consciousness.
of conditions for intubation—movement is decreased, the Those patients with an uncertain volume status and/or
patient is amnestic to the event, the vocal cords are re- tenuous hemodynamic stability are often administered
laxed and open, and the cough and gag reflexes are dimin- etomidate, because it is the IV hypnotic least likely to
ished.2 In routine anesthetic practice, in the elective case, cause a change in the patient’s heart rate or blood pressure.
the most commonly used IV anesthetics are propofol and Patients with frank shock, hypovolemia, and/or unstable
sodium thiopental. Muscle paralysis improves intubating hemodynamics are most appropriately managed with
conditions by causing the relaxation of head and neck ketamine as it has indirect sympathomimetic properties.
musculature and preventing the patient’s reflexive move- Intubation of unconscious patients who are moribund fre-
ments during direct laryngoscopy. Paralysis is frequently quently requires no medication administration for airway
obtained with succinylcholine, which has rapid onset and intervention as the severely compromised hemodynamics
50

CHAPTER 7 ■ PHARMACOLOGY FOR AIRWAY MANAGEMENT 51
Table 7-1
Agents Used for Preoperative or Preprocedural Sedation/Analgesia in Adults1
Agent Dose Effect

Midazolam 0.5–2 mg IV Anxiolysis, amnesia
Diazepam 2.5–5 mg IV Anxiolysis
Fentanyl 25–100 mcg IV Sedation, analgesia
Morphine 2.5–5 mg IV Sedation, analgesia
Table 7-2
IV General Anesthetic Agents for Induction of Anesthesia1
Duration of Action after

Agent IV Dose (mg/kg)a Time to Onset (s) Induction Dose (min)
Propofol Adults: 2–2.5 30 5–10
Pediatrics: 2.5–3.5
Sodium thiopental Adults: 3–5 30 5–10
Pediatrics: 4–7
Etomidate Adults: 0.25–0.3 15–45 3–12
Pediatrics: 0.3–0.4
Ketamine Adults: 1–3 45–60 10–20
Pediatrics: 2–4
a
As with all medications, dosing must be individualized to each patient. In particular, elderly patients may require significantly less medication to
achieve the desired effect.
Table 7-3
Commonly Selected Muscle Relaxants for Airway Management7
Intubating Dose (IV)

A gent (Category) (mg/kg) Time to Onset Duration (min)
Succinylcholine (depolarizing) Adult: 1.5 45 s 7–8
Pediatrics: 2a 45 s 7–8
Vecuronium (nondepolarizing) 0.1 2.5–3 min 30–45
Rocuronium (nondepolarizing) 0.6–1.2 1 min 30–45
Pancuronium (nondepolarizing) 0.06–0.1 3–4 min 60–100
Cisatracurium (nondepolarizing) 0.15–0.2 2–3 min 40–60
a
Succinylcholine is rarely given to infants or young children, given the risk of severe bradycardia. If given to this population, it is often administered
with atropine 10–20 mg/kg.
DESIGN SERVICES OF

Table 7-4
Adverse Responses and Contraindications to Succinylcholine8
Adverse Responses Contraindications

Muscle fasciculation Known allergy/sensitivity
Myalgias History of/risk of malignant hyperthermia
Masseter muscle hypertonicity/spasm Hyperkalemia
Hyperkalemia (can lead to dysrhythmia/cardiac arrest) Muscular dystrophy or myopathy
Increased intraocular pressure Lower motor neuron paralysisa
Increased intracranial pressure Upper motor neuron paralysisa
Allergic reaction (hives, anaphylaxis) Major burna
Malignant hyperthermia Known enzymatic deficiency
Bradycardia (pseudocholinesterase deficiency)
Prolonged blockade (phase 2 block/enzyme deficiency)
a
Risk of adverse effect is increased 24 h after acute insult onset.
may be catastrophically worsened if sedatives, analgesics, and Stept described application of cricoid pressure after
or hypnotics are administered in this setting.2 The patient administration of IV anesthetic)6; Table 7-5 outlines in full
in cardiac arrest likewise requires no pharmacologic inter- the current standard sequence for RSI as it compares to
vention in order to place the endotracheal tube. induction for elective intubation. In some circumstances,
Special attention should be given to the patient re- premedication before rapid sequence induction may serve
quiring emergent intubation who has not fasted or whose to reduce adverse responses to drugs or the physical ma-
gastric volume status is uncertain. A full stomach should nipulations of the airway. These include administration
be assumed in patients whose recent intake is uncertain, of lidocaine to blunt the impact of intubation on elevated
especially those with intestinal obstruction, those who intracranial pressure, opioids to reduce the hemodynamic
come to the hospital as trauma victims, and pregnant pa- response to laryngoscopy and intubation, or pretreatment
tients. These patients are at considerable risk for emesis with a small dose of a nondepolarizing neuromuscular
or passive regurgitation during the airway intervention blocking agent to reduce muscle fasciculations from suc-
process—the combination of a full stomach, lying supine, cinylcholine.
positive pressure ventilation for preoxygenation, and mus- Beyond the aforementioned common scenarios, famil-
cle paralysis can create a “perfect storm” for regurgitation iarity with other adjunctive pharmacology can be of ben-
of gastric contents into the mouth and subsequently the efit. There are situations in which standard endotracheal
airway and lungs. As a means to avoid aspiration, rapid intubation is not appropriate, and other airway manage-
sequence intubation (RSI) is often undertaken. Important ment methods and medications must be used. It is impor-
RSI variations from the elective situation include applica- tant to briefly address the common medications (Table 7-6)
tion of cricoid cartilage pressure before administration of that are used to facilitate the performance of two of the
airway management medications and the administration common alternative airway techniques available to physi-
of drugs quickly and sequentially without attempting to cians: nasotracheal intubation and awake fiberoptic intu-
mask ventilate the patient at any point in the airway man- bation (see Chapters 18 and 8). Many other techniques
agement process.3 Of historical note, the technique has are available, and these will be reviewed throughout the
undergone evolution since its inception (eg, Drs. Safar remainder of this book.
DESIGN SERVICES OF

CHAPTER 7 ■ PHARMACOLOGY FOR AIRWAY MANAGEMENT 53
Table 7-5
Comparison of Induction Sequences: Elective Intubation and Rapid Sequence Intubation1
Elective Intubation Sequence

1. Preparation (medications, suction, IV access, equipment)
2. Preinduction sedation (if required)
3. Placement of patient monitors
4. Preoxygenation via face mask
5. Administration of anesthetic induction agent
6. Mask ventilation
7. Administration of muscle relaxant
8. Mask ventilation
9. Direct laryngoscopy
10. Placement of endotracheal tube
11. Confirmation of correct tube placement in trachea
12. Fixation of endotracheal tube
RSI
1. Preparation (medications, suction, IV access, equipment)

2. Placement of patient monitors
3. Preoxygenation via face mask
4. Provision of cricoids pressure by assistant
5. Administration of induction agent
6. Administration of muscle relaxant
7. Direct laryngoscopy
8. Placement of endotracheal tube
9. Confirmation of correct tube placement in trachea
10. Release of cricoid pressure
11. Fixation of endotracheal tube
Table 7-6
Local Anesthetics for Airway Management1,9
Agent (Route of Common Dosage/

Airway Procedure Administration) Concentration Effect of Agent
Nasotracheal intubation Phenylephrine (topical 0.25–0.5% Vasoconstriction,
nasal spray) mucous membrane
shrinkage, tachycardia
Awake oral fiberoptic Glycopyrrolate (IV) 0.2 mg Antisialagogue
Lidocaine (transcutaneous 2 mL of 2% Local anesthetic
nerve block)
Lidocaine (topical to oral 3% Local anesthetic
mucosa)
Dexmetetomidine (IV) Loading dose: 1 mcg/kg given Sedation
over 10 min, followed by infusion
of 0.3 mcg/kg/min
DESIGN SERVICES OF

REFERENCES 6. Stept WJ, Safar PA. Rapid induction/intubation for pre-

vention of gastric-content aspiration. Anesth Analg. 1970;
1. Orebaugh SL. Atlas of Airway Management. Philadelphia, 49(4):633–636.
PA: Lippincott William & Wilkins; 2007. 7. Ovgenov OV, Dunn PF. Neuromuscular blockade. In:
2. Larson CP Jr. Airway management. In: Morgan GE, Levine WC, Allain RM, Alston TA, et al, eds. Clinical
Mikhail MS, Murray MJ, eds. Clinical Anesthesiology. 4th Anesthesia Procedures of the Massachusetts General Hospital.
ed. New York, NY: McGraw Hill; 2006:106–107. 8th ed. Philadelphia, PA: Lippincott Williams & Wilkins;
3. Henderson J. Airway management in the adult. In: Miller RD, 2010:165–179.
Eriksson LI, Fleisher LA, et al, eds. Miller’s Anesthesia. Vol 8. Orebaugh SL. Succinylcholine: adverse effects and alter-
2. 7th ed. Philadelphia, PA: Elsevier; 2009:1578–1579. natives in emergency medicine. Am J Emerg Med. 1999;17:
4. Snyed JR, O’Sullivan E. Tracheal intubation without neuro- 715–721.
muscular blocking agents: is there any point? Br J Anaesth. 9. Donnelly AJ, Baughman VL, Gonzales JP, et al. Anesthesiology
2010;104(5):628–632. & Critical Care Drug Handbook. 7th ed. Hudson, OH: Lexi-
5. Cote CJ. Pediatric anesthesia. In: Miller RD, Eriksson LI, Comp; 2006:370–371.
Fleisher LA, et al, eds. Miller’s Anesthesia. 7th ed. Vol 2.
Philadelphia, PA: Elsevier; 2009:2576–2577.
DESIGN SERVICES OF

CHAPTER
Regional Anesthesia Blocks

for Awake Intubation
8 cn
Nikhil Bhatnagar and Steven Orebaugh
INTRODUCTION Antisialogogues
Decreasing secretions will help with visualization when
In the American Society of Anesthesiologists difficult
doing an awake intubation. In addition, antisialogogues
airway algorithm, awake intubation is the mainstay of air-
facilitate the efficacy of local anesthetics by enhancing ab-
way management in situations where standard induction
sorption of local anesthetics at the site of action and by
and intubation of a patient may be lethal. In these patients,
decreasing dilution of the local anesthetics.
a successful awake intubation requires a skilled and expe-
Common drugs used are anticholinergics like atro-
rienced physician capable of properly preparing a patient.
pine 0.5 to 1.0 mg or glycopyrrolate 0.2 to 0.4 mg intra-
If done correctly, the psychological and physical trauma of
muscularly or intravenously.
the procedure is virtually eliminated.
The bulk of this chapter is dedicated to the anatomy Intravenous Sedation
of the upper airway as well as the various regional tech-
Judicious use of sedation is imperative in order to achieve
niques used when topicalizing the upper airway. It should
appropriate anxiolysis. The choices for sedation are nu-
be noted that any combination of these techniques can be
merous, and there are a few rules to follow to maintain
used and that not all of these techniques need to be per-
patient safety when preparing the patient for an awake
formed when topicalizing a patient. The choice of which
intubation.
techniques to use is based not only on indications and
The main rule is to use small amounts of sedation and
contraindications to the procedure but also on the skill
not to use several different types of sedation. The reason
and experience of the anesthesiologist performing these
for this is two-fold. The first reason is that overly sedating
procedures.
a patient can result in apnea, there by converting a con-
trolled airway to an uncontrolled emergency airway. The
second reason is that oversedation results in loss of what
PREPARATION little airway reflexes are left after topicalization, leading to
an increased risk of aspiration.
Even before anesthetizing the airway, there are several
Although not a comprehensive list, here are the main
steps that will need to be carried out in order to ensure a
classes of drugs used for sedation.
successful awake intubation.
1. Benzodiazapines—midazolam, lorazepam, and diaz-
Consent epam are examples. Midazolam is the most commonly
Awake intubations are one of the most terrifying and be- used in this class because of its short duration and rapid
wildering procedures a patient can experience. Explaining onset. When used alone, benzodiazepines do not cause
the procedure as well as explaining why the procedure the loss of airway reflexes and apnea commonplace with
is being performed will considerably help the patient to other classes of drugs. It should be noted that when
psychologically prepare for the procedure. benzodiazepines are combined with opioids, there will
This is also the time to assess whether the patient will be a synergistic effect on respiratory depression.
be able to fully cooperate. The patients most at risk are 2. Opioids—fentanyl, remifentanil, morphine, and di-
the very young, very old, and the mentally handicapped. laudid are examples. Fentanyl is the most commonly
Remember the one absolute contraindication to awake in- used in this class. Although effective for pain control as
tubation is patient refusal or an inability to cooperate. well as ablating the cough reflex, opioids are notorious
55

for depressing respiration and should be used in It should be noted that these local anesthetics are
smaller amounts. often used in combination to optimize the pharmacody-
3. N-Methyl-D-aspartic acid antagonist—ketamine is namics of both drugs. Hurricane spray is a combination
the main drug in this class. It has the advantage of of benzocaine and tetracaine, whereas Cetacaine spray is
sedation and pain control, without as much respira- a combination of benzocaine, tetracaine, butyl aminoben-
tory depression as other classes of drugs. It should zoate, benzalkonium chloride, and cetyldimethylethylam-
be noted that ketamine can cause hypertension and monium bromide.
tachycardia. In addition, ketamine has the well-
known side effects of excessive salivation as well
as hallucinations; so glycopyrrolate and midazolam NEUROANATOMY
should be used in conjunction with ketamine.
4. Alpha 2 antagonist—dexmedetomidine is the main AND REGIONAL BLOCKS
drug in this class. A relatively new drug, this drug In order to adequately perform nerve blocks of the upper
has the advantage of sedation and pain control airway, one should have a good understanding of the neu-
without the respiratory depression. When bolused, roanatomy of the upper airway. The main nerves that have
this drug causes an initial hypertension followed by to be blocked are the trigeminal nerve, glossopharyngeal
hypotension. Bradycardia is also a common problem nerve, and the vagus nerve. These blocks are further de-
with this drug. scribed and illustrated in chapter 23.
Trigeminal Nerve (Cranial Nerve V)

LOCAL ANESTHETICS The three main nerves from the trigeminal nerve that
have to be blocked are the anterior ethmoid nerve and the
The oropharynx, nasopharynx, and larynx are all highly
greater and lesser palatine nerves.
innervated, sensitive structures. As a result, instrumenta-
tion of these areas would be impossible without the use of Anterior Ethmoid Nerve
local anesthetics in the awake patient. Historically, several
A branch of the ophthalmic division of the trigeminal
types of local anesthetics have been used for this purpose;
nerve, it innervates the nares and the anterior third of the
but in modern practice, only three local anesthetics are
nasal septum (Fig. 8-1). This nerve can be easily blocked
used regularly when topicalizing the airway.
by placing a cotton swab along the dorsal surface of the
1. Lidocaine—this amide local anesthetic is by far the nose until the cribriform plate is reached. It is a valuable
most versatile local anesthetic used by anesthesiolo- block to perform when doing a nasal intubation.
gists. It has many preparations including IV, topical,
and aerosol. It has an intermediate duration and has
a maximum dose of 5 mg/kg without epinephrine and
7 mg/kg with epinephrine. A 1% or 2% concentrati-
non of lidocaine is injected for blocks of the nerves
of the airway, typically in a volume of 1-2 ml for each
site. Topical lidocaine can be administered in pled-
gets soaked with a 4% solution in small volumes of A
1-3 ml. In addition, 2% lidocaine can be nebulized to
provide topical anesthesia to the lower airways.
2. Tetracaine—this ester local anesthetic has the advan-
tage of having a longer duration due to its very slow
B
metabolism. Unfortunately, it also has a very slow
onset, is extremely toxic, and has a maximum safe
dose of 100 mg. It can be used both topically and in a
nebulized form.
3. Benzocaine—this ester local anesthetic has an ex-
tremely rapid onset and short duration of action. Its
maximum dose is 100 mg mainly due to the fact that
at higher doses it causes methemoglobinemia. At low
concentrations, methemoglobin is harmless; but at
higher concentrations, patients can become symp- FIG U RE 8-1 Neuroanatomy of the nasopharynx. A is the
tomatic and develop dyspnea, tachypnea, and cyano- anterior ethmoid nerve. B is the sphenopalatine ganglion with
sis that would need to be treated with methylene blue. the greater and lesser palatine nerves.

CHAPTER 8 ■ REGIONAL ANESTHESIA BLOCKS FOR AWAKE INTUBATION 57
Greater and Lesser Palatine Nerves of the middle turbinate until the posterior wall of the
These nerves come off the sphenopalatine ganglion, which nasopharynx is reached (Fig. 8-2).
itself comes off the maxillary division of the trigeminal 2. The invasive (oral) approach involves locating the
nerve (Fig. 8-1). These nerves innervate the rest of the greater palatine foramen that is located in the posterior
nasal mucosa as well as the nasopharynx. There are two lateral aspect of the hard palate about 1 cm medial to
main approaches to blocking these groups of nerves. the second and third molars. A spinal needle is then
inserted in a superior/posterior direction at a depth of
1. The noninvasive approach involves passing cotton 2 to 3 cm.
swabs soaked in local anesthetic along the upper border
Glossopharyngeal Nerve (Cranial Nerve IX)
The glossopharyngeal nerve is the main sensory nerve of
the oropharynx. From its origin in the medulla, the glos-
Sphenopalatine Olfactory nerves sopharyngeal nerve leaves the skull through the jugular
ganglion foramen and travels with the internal carotid and jugu-
lar vein for a time until it starts to travel anteriorly along
Middle the lateral surface of the pharynx in the palatoglossal arch
turbinate
(Fig. 8-3). There it splits into three branches. The lingual
Inferior branch innervates the vallecula, anterior surface of the
turbinate
epiglottis, and posterior third of the tongue. The walls of
the pharynx are innervated by the pharyngeal branch, and
the tonsils are innervated by the tonsillar branch.
There are several approaches that have been used
to block the glossopharyngeal nerve. The noninvasive
approach involves taking cotton balls soaked with local
anesthetic and placing them in the inferior-most portion
of the soft-tissue fold that makes up the palatoglossal arch.
If this approach proves inadequate, then a more inva-
sive approach can be performed. In this approach, a 22G
F I GUR E 8 -2 Schematic of the noninvasive approach to do or smaller needle is inserted in the inferior aspect of the
a sphenopalatine nerve block. palatoglossal arch (Fig. 8-4). An aspiration test is done in
FIG U RE 8-3 The arrow points to the palato-

glossal arch, the glossopharyngeal nerve lies at
the base of this structure. In this area, the glos-
sopharyngeal nerve is easy to block with both
invasive and noninvasive approaches.
(Reused with permission from Rosenblatt WH,
Sukhupragarn W. Airway management. In:
Barash PG, Cullen BF, Stoelting RK, et al, eds.
Clinical Anesthesia. 6thed. Philadelphia, PA:
Lippincott Williams & Wilkins; 2009: 775.)

Hyoid
Thyroid
Crycoid
F I GUR E 8 -4 The invasive intraoral approach to a glosso-

pharyngeal nerve block.
(Reused with permission from www.nysora.com/peripheral_
nerve_blocks/head_and_neck_block/3049-regional-topical-
anesthesia-endotracheal-intubation.html)
B
X
FIG U RE 8-6 Superior laryngeal nerve block and relevant
anatomy.
(Reused with permission from Hagberg CA. Airway blocks. In:
Superior Chelly JE, ed. Peripheral Nerve Blocks: A Color Atlas. 2nded.
laryngeal Philadelphia, PA: Lippincott Williams & Wilkins; 2009:
nerve
181–182.)
Recurrent
laryngeal Superior Laryngeal Nerve
nerve The superior laryngeal nerve is made up of two com-
F I GUR E 8 -5 The innervations of the larynx by the vagus ponents, the internal and external branch. The internal
nerve. The first branch coming off is the superior laryngeal division provides sensory innervation to the base of the
nerve and the second branch coming off is the recurrent tongue, epiglottis, supraglottic mucosa, thyroepiglottic
laryngeal nerve. joint, and cricothyroid joint. The internal division has no
motor innervations. The external division provides sen-
sory innervations to the anterior subglottic mucosa as well
as motor innervations to the cricothyroid muscle.
order to make sure no blood is seen as the carotid artery is Anatomically, the superior laryngeal nerves lie be-
in close proximity to the glossopharyngeal nerve. tween the greater cornu of the hyoid bone and superior
cornu of the thyroid cartilage. The internal branch of the
Vagus Nerve superior laryngeal nerve pierces the thyrohyoid mem-
The vagus nerve is the major parasympathetic nerve and brane, whereas the external branch remains superficial to
hence innervates many organs in the body. The upper the membrane.
airway is innervated by two major branches of the vagus The invasive superior laryngeal nerve block involves
nerve, the superior laryngeal nerve and the recurrent la- identifying either the superior cornu of the thyroid carti-
ryngeal nerve (Fig. 8-5). lage or the greater cornu of the hyoid bone. The best way

CHAPTER 8 ■ REGIONAL ANESTHESIA BLOCKS FOR AWAKE INTUBATION 59
FIG U RE 8-7 Transtracheal nerve block of the

recurrent laryngeal nerve and relevant anatomy.
(Reused with permission from Hagberg CA.
Airway blocks. In: Chelly JE, ed. Peripheral Nerve
Blocks: A Color Atlas. 2nded. Philadelphia, PA:
Lippincott Williams & Wilkins; 2009:183–184.)
to demonstrate this is to apply pressure to the other side Recurrent Laryngeal Nerve
of the larynx, so that these boney and cartilage landmarks The recurrent laryngeal nerve provides sensory
become more prominant. Then with a 22G or smaller nee- innervations to the subglottic mucosa and muscle spindles
dle, the operator walks inferiorly off the greater cornu of and provides a motor innervation to the thyroarytenoid,
the hyoid bone or walks superiorly off the superior cornu lateral cricoarytenoid, interarytenoids, and posterior cri-
of the thyroid cartilage until the thyrohyoid membrane is coarytenoids.
pierced (Fig. 8-6). Care must be taken to make sure that The main way to block the recurrent laryngeal nerve
blood is not aspirated back from the needle as the carotid is by a transtracheal approach. In this approach, the thy-
artery is in close vicinity. If air is aspirated, then the needle roid cartilage is identified superiorly in the neck, and the
is too deep and may have penetrated the trachea. cricoid cartilage is identified inferiorly in the neck. In
The noninvasive oral approach involves grasping between these two cartilages lies the cricothyroid mem-
the tongue with a piece of gauze and then with Krause brane. Using a 22G or smaller needle, one can pierce
forceps placing a piece of lidocaine soaked gauze over the this membrane until air is aspirated. At that time, local
lateral tongue and then eventually in the piriform sinuses anesthetic can be injected (Fig. 8-7). The needle should be
bilaterally. aimed inferiorly to avoid vocal cord injury.

It is also possible to anesthetize the recurrent laryn- REFERENCES

geal nerves by directly spraying local anesthetic solution
through a fiberoptic bronchoscope as it is inserted into the 1. Barash PG, Cullen BF, Stoelting RK, et al. Clinical Anesthesia.
airway during an awake intubation procedure. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins;
2009:751–793.
2. Stoelting RK, Miller RD. Basics of Anesthesia. 5th ed.
Philadelphia, PA: Elsevier; 2007:207–241.
CONCLUSIONS 3. Ovassapian A. Fiberoptic Endoscopy in Anesthesia and Critical
Care. New York, NY: Raven Press; 1990:57–74.
The upper airway is an extremely sensitive area that is 4. Patil UV, Stehling LC, Zauder HL. Fiberoptic Endoscopy in
innervated by several different nerves. As a result, there Anesthesia. St. Louis, MO: CV Mosby; 1983.
is no one nerve block that will completely topicalize the 5. Chelly JE. Peripheral Nerve Blocks. 2nd ed. Philadelphia, PA:
airway. However, if one appreciates the anatomy of the W.B. Saunders Co; 2004.
upper airway and takes a holistic approach to awake intu- 6. Brown DL. Atlas of Regional Anesthesia. 2nd ed. Philadelphia,
bation, including proper counseling, premedication, and PA: W.B. Saunders Co; 1999.
nerve blocks, then the actual intubation will be comfort- 7. www.nysora.com/peripheral_nerve_blocks/head_and_
neck_block/3049-regional-topical-anesthesia-endotracheal-
able, painless, and safe for the patient.
intubation.html.

PART
Difficult Airway Management: Recognition,
II Training and Management
CHAPTER
Definition, Incidence, and 9 cn
Predictors of the Difficult Airway

Arun L. Jayaraman and Paul E. Biegeleisen
T he term “difficult airway” defies simple characterization

as there is no published standard definition. It may
be interpreted to indicate challenging or impossible
significant impedance to gas entry or exit.4,5 Furthermore,
these guidelines enumerate sundry signs of ineffective
mask ventilation, including inadequate chest excur-
mask ventilation (IMV), glottic visualization, and/or sion, inadequate breath sounds, auscultatory evidence
endotracheal tube placement. Regardless, prudence dic- of obstruction, cyanosis, gastric insufflation, inadequate
tates careful study of these aspects of airway management. SpO2, inadequate end-tidal carbon dioxide, inadequate spi-
This is particularly true when considering that examina- rometric measures of exhaled gas flow, and hemodynamic
tion of the American Society of Anesthesiologists closed changes associated with hypoxemia and/or hypercapnia.
claims project indicates that a significant proportion of Despite the importance of adequate mask ventilation
adverse anesthetic outcomes were associated with respi- in managing the difficult airway, as emphasized in the
ratory events, including inadequate ventilation, difficult American Society of Anesthesiologist’s difficult airway al-
tracheal intubation, and esophageal intubation, account- gorithm, research examining the incidence and predictors
ing for significant morbidity and mortality.1 Of note, many of DMV is somewhat sparse, particularly when compared
of these events were deemed to be preventable. Similar with that regarding difficult tracheal intubation. An obser-
observations were made in a retrospective analysis of over vational study involving 1,502 adults undergoing abdomi-
80,000 anesthetics.2 As such, the subsequent text contains nal, gynecologic, orthopedic, urologic, and neurosurgery
a discussion of the definition, incidence, and predictors of with general anesthesia indicates that DMV may be as
difficult mask ventilation (DMV) and difficult intubation common as 5%.6 The incidence of IMV was 0.07%. This
(DI) in adults. study identified several independent risk factors for DMV/
IMV: age > 55 years, BMI > 26 kg/m2, presence of a beard,
lack of teeth, and history of snoring. Interestingly, reduced
DIFFICULT MASK VENTILATION mouth opening and a receding mandible, two indicators of
DI which will be discussed in more detail subsequently,
DMV has been defined using various criteria, including were not associated with DMV in a statistically significant
poor oxygenation as detected via pulse-oximetry, fashion. Of concern, preoperative airway assessment only
inadequate chest excursion, a leak around the mask, and predicted DMV in 17% of patients with DMV.
necessity of two-handed mask ventilation. Previously, the In another observational study involving 22,660 adults
American Society of Anesthesiologists Practice Guidelines undergoing general anesthesia, the authors observed an in-
for Management of the Difficult Airway defined DMV as cidence of 1.4% for DMV and 0.16% for IMV,7 as assessed
the inability of an unassisted anesthesiologist to either using a previously proposed numerical grading scale for
maintain an SpO2 > 90% using 100% oxygen and positive mask ventilation.8 This study identified several independent
pressure mask ventilation (in a patient whose SpO2 was risk factors for DMV and IMV. Specifically, predictors of
greater than 90% prior to induction of anesthesia) or to DMV included age ≥ 57 years, BMI ≥ 30 kg/m2, Mallampati
prevent or reverse signs of inadequate ventilation during III or IV classification, presence of a beard, severely lim-
positive pressure mask ventilation.3 The updated guide- ited jaw protrusion, and snoring. Predictors of IMV were
lines provide a broader definition of DMV as the inability a history of snoring and thyromental distance (TMD) less
of an anesthesiologist to provide adequate mask venti- than 6 cm. Of note, a subsequent study by the same group
lation due to poor mask seal, excessive gas leak, and/or involving 53,041 adults undergoing general anesthesia
61

62 PART II ■ DIFFICULT AIRWAY MANAGEMENT: RECOGNITION, TRAINING AND MANAGEMENT
identified several additional independent predictors of Overall, the incidence of difficult laryngoscopy, defined
IMV, including male sex, history of obstructive sleep ap- as Cormack-Lehane laryngoscopic view ≥ 3 (Fig. 9-1A–E),
nea (OSA), history of neck irradiation, Mallampati III or IV is 1% to 4%,whereas that of failed intubation is 0.05%
classification, and presence of a beard.9 Independent risk to 0.35%.14 Of note, the probability of encountering IMV
factors for difficult or impossible mask ventilation and DI and impossible endotracheal intubation in the same pa-
were BMI≥30 kg/m2, limited or severely limited mandibular tient is estimated at 0.0001% to 0.02%.14 The importance
protrusion, abnormal neck anatomy, history of snoring, and of predicting DI is underscored by a large retrospective
history of OSA. study which found that almost half of anesthetic compli-
Despite differences in the incidences of DMV and IMV cations related to airway management were preventable,
described in published studies, ranging from 1.4% to 7.8% as they were thought to be a consequence of either failed
and 0.07% to 0.16%, respectively, which are likely attribut- recognition of DI or inappropriate choice of intubating
able to varying definitions, common independent risk fac- technique.2
tors for DMV/IMV include increased age, increased BMI,
presence of a beard, and snoring.6,7,9–11 Although there is History of Difficult Intubation
no single ideal means of prospectively screening patients History of DI is likely the most reliable predictor of future
for the likelihood of DMV/IMV, common sense indicates DI.15,16 Among the various prognostic factors for DI, his-
that one should consider a combination of factors that tory of DI is of particular value as it aids the clinician in
would maximize sensitivity, potentially at the expense managing the airway of a patient in whom intubation may
of specificity. A reasonable set of criteria for predicting not be predicted to be problematic by other measures. As
DMV/IMV may include history of DMV/IMV, abnormal such, the practice at our institution is to document DI
neck anatomy/craniofacial abnormality, history of neck in such a fashion that it is prominently displayed in the
irradiation, male sex, increased age, increased BMI, his- electronic medical record along with pertinent details and
tory of snoring or OSA, Mallampati III or IV classifica- future recommendations; patients are also given a letter
tion, limited jaw protrusion, lack of teeth, presence of a to show those that cannot access the electronic record.
beard, poor atlanto-occipital extension, and pharyngeal Of course, although a history of DI does not necessarily
pathology. Unfortunately, there is no robust prospectively indicate future difficulty, prudence dictates a cautious and
validated screening algorithm for DMV/IMV. Having said determinate approach to airway management in these pa-
that, one would anticipate the pretest probability of DMV/ tients. The corollary to this is that airway management
IMV increasing in proportion to the number of posi- may not remain facile in a given patient although it was
tive risk factors. The only readily modifiable risk factor previously documented as such.
is presence of a beard. Of interest, most published data
indicate a strong correlation between difficult ventilation Mallampati Classification
and intubation.6,9,10,12 This is not surprising as many of the Including modifications, Mallampati scoring is the most
predictors for DMV/IMV also apply to DI, as detailed in widely used and studied preoperative airway examination
the following text. tool, so much so that it is a standard component of the
preoperative evaluation. Mallampati classification pro-
vides a qualitative estimate of tongue size relative to the
DIFFICULT INTUBATION oropharyngeal cavity, as the tongue must be displaced into
the floor of the mouth in order to visualize the larynx dur-
As with DMV, DI has been defined in various ways. In ing direct laryngoscopy. The Mallampati score is deter-
practice, DI frequently results from inability to obtain mined by the ability to visualize the uvula, faucial pillars,
adequate glottic visualization with laryngoscopy. The and/or soft palate.17,18 The original classification scheme
American Society of Anesthesiologists Practice Guidelines comprised three categories of oropharyngeal classification
for Management of the Difficult Airway defines difficult that were found to correlate with glottic exposure dur-
laryngoscopy as impossible visualization of any portion ing direct laryngoscopy in a statistically significant fashion:
of the vocal cords following multiple attempts at conven- Mallampati I indicates visualization of the uvula, faucial
tional laryngoscopy. DI is characterized as requiring mul- pillars, and soft palate; in the Mallampati II classification
tiple attempts, whereas failed intubation is described as the uvula is masked by the base of the tongue but the fau-
inability to properly place an endotracheal tube despite cial pillars and soft palate remain visible; and Mallampati
multiple attempts.4 III denotes visualization of the soft palate only. Samsoon
A large prospective observational study involv- and Young19 subsequently modified the Mallampati scoring
ing 18,500 patients indicates incidences of difficult and system, adding Mallampati IV, which refers to visualiza-
failed intubation of 1.8% and 0.3%, respectively.13 This tion of the hard palate only, as their retrospective analysis
study showed a positive correlation between DI and obe- of 13 failed intubations linked the Mallampati IV clas-
sity, decreased TMD, limited mouth opening, reduced sification to failed intubation. This modified Mallampati
neck extension, male sex, and poor laryngeal exposure.13 score (MMS) is depicted in Fig. 9-2A–E.
DESIGN SERVICES OF

CHAPTER 9 ■ DEFINITION, INCIDENCE, AND PREDICTORS OF THE DIFFICULT AIRWAY 63
Grade I Grade II Grade III Grade IV
B C
D E
F I GUR E 9 -1 Cormack-Lehane grading of glottic exposure with direct laryngoscopy. A: Grades of laryngeal exposure.
(From Samsoon GL, Young JR. Difficult tracheal intubation: a retrospective study. Anesthesia. 1987;42:487–490 with permis-
sion.) B–E: Photographs of the various Cormack-Lehane grades, appear in order of increasing score — B: Grade 1 laryngeal
exposure; C: Grade 2 laryngeal exposure; D: Grade 3 laryngeal exposure; E: Grade 4 laryngeal exposure.
Of note, as originally described, the Mallampati clas- indicates that ideal assessment occurs with the patient
sification was assessed with the patient sitting upright sitting with head extended, tongue maximally protruded,
and tongue maximally extended; head positioning and and phonation.20 Subsequent comparisons of this ex-
phonation were not specified.18 In developing the MMS, tended Mallampati score (EMS) with MMS suggest that
Samsoon and Young19 used the sitting position with the EMS is associated with 7% to 10% increased specificity,
head neutral and tongue extended; phonation was not up to 83%, for difficult laryngoscopy and comparable
specified. A subsequent prospective analysis investigat- sensitivity.21,22 Interestingly, there is some data indicat-
ing the effects of patient positioning on oropharyngeal ing that MMS grade is increased by changing from the
classification, which was in turn correlated with ease of sitting to supine position.23 Furthermore, MMS assess-
direct laryngoscopy using the Cormack-Lehane system, ment done in the supine position may be associated with
DESIGN SERVICES OF

Class I Class II Class III Class IV
B C
D E
F I GU R E 9- 2 Modified Mallampati scoring. A: A depiction of the Samsoon and Young modification of Mallampati oropharyn-
geal assessment.
(From Jackson C. The technique of insertion of intratracheal insufflation tubes. Surg Gynecol Obstet. 1913;17:507–509
with permission; From Magill IW. Technique in endotracheal anesthesia. Br Med J. 1930;2:817–819 with permission.) B–E:
Photographs of the various modified Mallampati classes, appear in order of increasing score — B: class 1 view of the oropharynx;
C: class 2 view of oropharynx; D: class 3 view of oropharynx; E: class 4 view of oropharynx.
DESIGN SERVICES OF

A B
F I GUR E 9 -3 Depiction of normal cervical range of motion. A: Neutral position. B: Full extension at the atlanto-occipital joint
should be 35°.
increased positive predictive value for difficult laryngos- comparing laryngoscopic view with and without MILS in the
copy compared with that done in the sitting position.24,25 same individuals, the authors found that, with MILS, laryn-
Fig. 9-2 contains photographs of the four classes in the geal exposure was reduced in 45% of participants and that
modified Mallampati scheme and four grades of glottis only the epiglottis was visible in 22% of subjects.33 These
exposure of the Cormack-Lehane system. findings only further complicate airway management of a
patient who one may not have had the opportunity to ad-
Cervical Spine Range of Motion equately assess prior to induction/airway instrumentation.
The importance of craniocervical extension in facilitating
endotracheal intubation via direct laryngoscopy has been Inter-incisor Distance
described as early as 1913 (Fig. 9-3A, B).26 The utility of IID, which is a measure of mouth opening, incisor promi-
atlanto-occipital extension and cervical flexion (the “sniff- nence, and temperomandibular joint mobility, indicates
ing” position) results from aiding in alignment of the oral, ease of laryngoscopy as it assesses the space available for
pharyngeal, and laryngeal axes.27 Moreover, craniocervical insertion and manipulation of the laryngoscope and endo-
extension also facilitates intubation by enhancing mouth tracheal tube (Fig. 9-4).An adequate IID is considered to
opening.28 In order to properly assess cervical range of be 3 to 5 cm or 2 to 3 fingerbreadths between the central
motion (CROM), one must examine both flexion of the maxillary and mandibular incisors with maximal mouth
lower cervical spine and extension of the atlanto-occipital opening, as shown in Fig. 9-4. Reduced IID may be due
joint, as seen in Fig. 9-3. Numerous studies have verified to decreased temperomandibular joint mobility or promi-
the role of limited cervical spine mobility, often defined nent incisors. Prominent maxillary incisors may impede
as CROM < 80° to 90°, in predicting DI with direct laryn- laryngoscopy by resulting in a more posterior view of the
goscopy.22,29–31 Retrospective examination of over 1,000 larynx. Additionally, poor dentition requires added care to
intubations in patients with limited cervical spine mobil- avoid dental trauma, potentially involving manipulation
ity indicates that age ≥ 48 years, MMPIII or IV status, and of the laryngoscope into less than optimal positions.
TMD < 6 cm are independent predictors of DI in this pa-
tient population.22 Thyromental Distance
These considerations are also relevant to airway man- The TMD is the length between the thyroid cartilage
agement of patients with unstable cervical spines, includ- and the mentum, or chin, as measured with the patient’s
ing trauma patients who require emergent intubation. In head in maximal atlanto-occipital extension, as depicted
these patients, the standard approach is to carefully remove in Fig. 9-5. Some data indicate that it may be better to
the cervical collar and maintain manual inline stabilization measure from the inner rather than the outer mentum,
(MILS) of the cervical spine. This is done as cervical collars perhaps due to variability in subcutaneous fat on the bony
have been shown to reduce laryngeal exposure secondary to prominence of the chin.35 TMD measurement provides
decreased inter-incisor distance (IID), resulting in a more insight into the mandibular space length available for dis-
posterior view of the glottic aperture.32 Unsurprisingly, there placement of the tongue into during laryngoscopy. A TMD
is also data indicating that laryngeal exposure is reduced of less than 6 cm (width of three middlemost fingers) is
with MILS.33,34 Specifically, in one study of over 150 subjects a risk factor for DI, although this has been challenged by
DESIGN SERVICES OF

F I GUR E 9 -4 Assessing inter-incisor distance. Normal range FIG U RE 9-5 Assessment of thyromental distance, from
of motion of the temporomandibular joint should permit the mentum of the mandible to the superior margin of the
insertion of three fingers aligned vertically into the mouth. thyroid cartilage, should exceed 6 cm or 3 fingerbreadths.
some.36 Of note, a very long TMD may predispose to DI buck teeth, receding mandible, and MMS III-IV), only
due to a more caudally displaced larynx, resulting in more MMS III-IV is a statistically significant risk factor for DI
of the tongue being present in the hypopharynx, in turn in obese patients, and even this showed relatively poor
rendering laryngoscopy more challenging.36–38 Several sensitivity, specificity, and negative predictive value.44
studies indicate that TMD has high specificity but poor A subsequent study showed a similar increase in likeli-
sensitivity in predicting DI.39,40 hood of DI, as assessed using the IDS, of 3% versus 14.5%
in lean (BMI < 30 kg/m2) and obese (BMI ≥ 30 kg/m2)
Obesity patients, respectively.45 Apart from increased BMI, other
Numerous, but not all, studies indicate a link between statistically significant risk factors for DI identified
obesity and increased likelihood of difficult airway man- in this study include MMS≥3 and neck circumference
agement. This is commonly attributed to an enlarged > 43 cm, as measured at the level of the thyroid carti-
tongue and redundant soft tissue. Also, obese patients will lage; interestingly, in this study, increased neck circum-
decompensate/desaturate sooner following apnea than ference is also a predictor of DI in lean patients. Another
their nonobese counterparts. As discussed previously, report examining morbidly obese patients (BMI > 40 kg/
there is significant data correlating obesity with difficult m2) linked MMS ≥ 3 and increased neck circumference at
ventilation; in these studies, obesity was defined as a BMI the level of the thyroid cartilage, but not increased BMI,
greater than either 26 or 30 kg/m2.6,7,9 There are similar with DI in this patient population.46 In contrast, an anal-
data regarding obesity and DI. Of note, there are two spe- ysis of morbidly obese patients (mean BMI 49.4 kg/m2)
cific questions to consider: comparing the incidence of DI undergoing bariatric surgery found a significant correla-
in lean versus obese patients and determining whether, tion between DI and male gender as well as MMS ≥ 3 but
among obese patients, increased BMI serves as an indepen- not increased BMI, increased neck circumference, or his-
dent predictor of DI. tory of OSA; increased neck circumference was associated
A study of over 1,800 patients found that obesity, with difficult laryngoscopy but not DI.47 Of note, although
defined as a BMI > 30 kg/m2, results in an almost three- obesity renders mask ventilation more problematic, some
fold increase in the incidence of difficult laryngoscopy.41 maintain that, with proper planning and positioning (ie,
Similarly, a meta analysis of 35 studies indicates more a “ramp”), obesity alone does not predispose to DI.48,49
than a three-fold increase in DI in obese versus lean
patients.42 Another investigation reported that the in- Upper Lip Bite Test
cidence of DI, as assessed using the intubation difficult Although the upper lip bite test (ULBT) is a relatively
scale (IDS),43 is 2.2% in lean patients (BMI < 30 kg/m2) new assay, the notion that receding and/or poorly mobile
and 15.5% in obese patients (BMI ≥ 35 kg/m2).44 This mandibles hinder laryngoscopy is not a novel one.50 The
study also concludes that, of the examined character- ULBT was initially proposed as a possible replacement
istics (age, sex, BMI, snoring, OSA, diabetes, mouth for MMS in predicting difficult laryngoscopy.51 ULBT
opening < 3.5 cm, neck movement < 80°, missing teeth, serves as an indicator of the roles of mandibular mobility,
DESIGN SERVICES OF

or lack thereof, and dental architecture in impeding patients, with rapid correction, and 5% of patients requir-
laryngoscopy. There are three ULBT classes: in class I, ing three or more attempts at direct laryngoscopy. Also,
the mandibular incisors can bite the upper lip above the 1% of patients required an emergent surgical airway.
vermilion line; in class II, the mandibular incisors can bite Overall, the range of DI in this study appears to be be-
the upper lip below the vermilion line; and in class III, the tween 5% and 27%, depending on the extent of overlap.58
mandibular incisors cannot bite the upper lip.51 Although In the investigation of Tayal et al, the proportion of
not nearly as thoroughly evaluated as MS/MMS, some but patients whom the investigators were unable to manage
not all data indicates that the ULBT assay may be more with direct laryngoscopy was similarly low, with only 1%
specific than MMS in predicting DI with comparable sen- requiring a surgical airway. However, 30% of patients who
sitivity.51,52 As compared with other tests, specific advan- were intubated were not included in the analysis because
tages of this assay include ease of use and interobserver they did not meet the investigators’ requirements for eligi-
reliability.52 Interestingly, there is some data indicating bility for RSI. Thus, the actual incidence of DI lies some-
that ULBT may also serve as a predictor of difficult ven- where between the extremes of 1% and 31%.59Even if the
tilation.53 Furthermore, ULBT may be a more sensitive lower range is chosen, DI in the ED is not rare and seems
predictor of DI using the Glidescope video laryngoscope to be more common than in the population presenting
than MMS.54 for elective surgery. In a multicenter study of ED airway
management in more than 6,300 cases, the incidence of
esophageal intubation was found to be 4%, and the failure
Airway Management Outside of the rate for intubation when RSI was used to secure the airway
Operating Room was less than 2%.60,61
There are significant difficulties encountered in emergent
airway management that are not encountered in the elec-
tive, preoperative setting. As noted previously, obtaining
a history and physical examination may be impossible
SPECIAL CIRCUMSTANCES
when the patient is obtunded or severely dyspneic, and Please note that there are certain conditions, not discussed
time is of the essence. Furthermore, the very nature of the in the preceding text, that further predispose to DMV/
emergency may lead to increased difficulty in ventilation DI. These include acute infections (ie, croup, epiglotti-
and laryngoscopy. The presumption of a “full stomach” tis, and retropharyngeal/tonsillar abscesses), ankylosing
in all patients intubated emergently dictates use of the spondylitis, burns, certain congenital disorders/syndromes
rapid sequence intubation (RSI) technique. The imposi- (ie, acromegaly, choanal atresia, Downs syndrome, muco-
tion of cricoid pressure and of laryngoscopy at the earli- polysaccharidoses, PierreRobin sequence, TreacherCollins
est possible moment after administration of hypnotics and syndrome, etc.), diabetes mellitus, pregnancy, rheumatoid
muscle relaxants may increase the physician’s stress level arthritis, tumors of the upper airway, and upper airway
and distort the view of the larynx.55 The trauma patient trauma. This is not intended to be an exhaustive list, and
places even more obstacles in the path of the intubating some of these conditions will be discussed further else-
physician: facial distortion, secretions, swelling, mandibu- where in this text.
lar injury, and potential cervical spine injury all combine
to make these patients among the most challenging airway
management problems.56 As discussed previously, cervical
collars and in-line immobilization impact glottic exposure
SUMMARY
adversely, and up to 20% of these patients may have a There are certain circumstances, such as gross cranio-
grade 3 or grade 4 laryngoscopic view.33 In fact, a recent cervical pathology, which render airway assessment easy.
observational study of over 3,000 emergent nonoperative These are situations where one aspect of the examina-
intubations found an incidence of DI of 10.3% and that tion is so telling that it renders the remainder of the as-
of complications related to intubation of 4.2%, higher sessment almost irrelevant. Such cases are relatively in-
than typically seen in the operating room.57 Independent frequent. In most patients, one applies a series of tests,
predictors of complications included general floor and the subjective sum of which form the basis of the airway
emergency department (ED)but not intensive care unit assessment. As expected, there are data showing that sen-
locations. sitivity and specificity is increased by considering sev-
The incidence of DAM in the ED population has not eral parameters, typically including history of DI, MMS/
been studied as thoroughly as that in the operating room. EMS, CROM, TMD, IID, dentition, BMI, and/or ULBT.
Sakles et al report intubation of 610 patients in an urban Unfortunately, efforts to prospectively validate an airway
ED over a 1-year period, 84% of whom were managed assessment tool using such assays have not yielded a sin-
with the RSI technique and 16% of whom were deemed gle gold standard rubric. Thus, airway assessment often
unfit for RSI. The overall success rate of these intubations becomes an interplay between physical examination and
was 99%, with esophageal intubation occurring in 5% of clinical experience.
DESIGN SERVICES OF

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6. Langeron O, Masso E, Huraux C, et al. Prediction of dif- flation tubes. Surg Gynecol Obstet. 1913;17:507–509.
ficult mask ventilation. Anesthesiology. 2000;92:1229–1236. 27. Magill IW. Technique in endotracheal anesthesia. Br Med J.
7. Kheterpal S, Han R, Tremper KK, et al. Incidence and 1930;2:817–819.
predictors of difficult and impossible mask ventilation. 28. Hidaka S, Nakagawa I, Uesugi F, et al. Mouth opening in
Anesthesiology. 2006;105:885–891. relation to the craniocervical position during induction of
8. Han R, Tremper KK, Kheterpal S, et al. Grading scale for general anesthesia. Masui. 2005;54:370–375.
mask ventilation. Anesthesiology. 2004;101:267. 29. Calder I, Calder J, Crockard HA. Difficult direct laryngos-
9. Kheterpal S, Martin L, Shanks AM, et al. Prediction and out- copy in patients with cervical spine disease. Anaesthesia.
comes of impossible mask ventilation: a review of 50,000 1995;50:756–763.
anesthetics. Anesthesiology. 2009;110:891–897. 30. Arné J, Descoins P, Fusciardi J, et al. Preoperative as-
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of difficult mask ventilation. J Anesth. 2005;19:7–11. gery: predictive value of a clinical multivariate risk index.
11. El-Orbany M, Woehlck HJ. Difficult mask ventilation. Br J Anaesth. 1998;80:140–146.
Anesth Analg. 2009;109:1870–1880. 31. Karkouti K, Rose DK, Wigglesworth D, et al. Predicting
12. Cattano D, Panicucci E, Paolicchi A, et al. Risk factors difficult intubation: a multivariable analysis. Can J Anesth.
assessment of the difficult airway: an Italian survey of 1956 2000;47:730–739.
patients. AnesthAnalg. 2004;99:1774–1779. 32. Goutcher CM, Lockhead V. Reduction in mouth opening with
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in 18,500 patients. Can J Anesth. 1994;41:372–383. 33. Nolan JP, Wilson ME. Orotracheal intubation in pa-
14. Klock AP, Benumof JL. Definition and incidence of the difficult tients with potential cervical spine injuries. Anaesthesia.
airway. In: Hagberg CA, ed. Benumof’s Airway Management. 1993;48:630–633.
Philadelphia, PA: Mosby; 2007: 215–220. 34. Santorini BG, Hindman BJ, Puttlitz CM, et al. Manual in-
15. Reed AP. Evaluation and recognition of the difficult air- line stabilization increases pressures applied by the laryn-
way. In: Hagberg CA, ed. Benumof’s Airway Management. goscope blade during direct laryngoscopy and orotracheal
Philadelphia, PA: Mosby; 2007: 221–235. intubation. Anesthesiology. 2009;110:24–31.
16. Lundstrøm LH, Møller A, Rosenstock C, et al. High body 35. Lewis M, Keramati S, Benumof JL, et al. What is the best
mass index is a weak predictor for difficult and failed tra- way to determine oropharyngeal classification and man-
cheal intubation: a cohort study of 91,332 consecutive dibular space length to predict difficult laryngoscopy?
patients scheduled for direct laryngoscopy registered in the Anesthesiology. 1994;81:69–75.
Danish anesthesia database. Anesthesiology. 2009;110:266– 36. Benumof JL. Both a large and small thyromental distance
274. can predict difficult intubation. Anesth Analg. 2003;97:1543.
17. Mallampati SR. Clinical sign to predict difficult tracheal 37. Chou HC, Wu TL. Large hypopharyngeal tongue: a shared
intubation (hypothesis). Can Anaesth Society J. 1983;30: anatomic abnormality for difficult mask ventilation, diffi-
316–317. cult intubation, and obstructive sleep apnea? Anesthesiology.
18. Mallampati SR, Gatt SP, Gugino LD, et al. A clinical sign 2001;94:936–937.
to predict difficult tracheal intubation: a prospective study. 38. Chou HC, Wu TL. Thyromental distance and anterior lar-
Can Anaesth Society J. 1985;32:429–434. ynx: misconception and misnomer? Anesth Analg. 2003;96:
19. Samsoon GL, Young JR. Difficult tracheal intubation: a ret- 1526–1527.
rospective study. Anesthesia. 1987;42:487–490.
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39. el-Ganzouri AR, McCarthy RJ, Tuman KJ, et al. Preoperative Mallampati classification in predicting difficulty in endotra-
airway assessment: predictive value of a multivariate risk cheal intubation: a prospective blinded study. Anesth Analg.
index. Anesth Analg. 1996;82:1197–1204. 2003;96:595–599.
40. Ayuso MA, Sala X, Luis M, et al. Predicting difficult intuba- 52. Eberhart LHJ, Arndt C, Cierpka T, et al. The reliability and
tion in pharyngo-laryngeal disease: preliminary results of a validity of the upper lip bite test compared with Mallampati
composite index. Can J Anesth. 2003;50:81–85. classification to predict difficult laryngoscopy: an external
41. Voyagis GS, Kyriakis KP, Dimitriou V, et al. Value of oro- prospective evaluation. Anesth Analg. 2005;101:284–289.
pharyngeal Mallampati classification in predicting difficult 53. Khan ZH, Mohammadi M, Rasouli MR, et al. The diagnostic
laryngoscopy among obese patients. Eur J Anaesthesiol. value of the upper lip bite test combined with sternomental
1998;15:330–334. distance, thyromental distance, and inter-incisor distance
42. Shiga T, Wajima Z, Inoue T, et al. Predicting difficult in- for prediction of easy laryngoscopy and intubation: a pro-
tubation in apparently normal patients: a meta-analysis spective study. Anesth Analg. 2009;109:822–824.
of bedside screening test performance. Anesthesiology. 54. Tremblay MH, Williams S, Robitaille A, et al. Poor
2005;103:429–437. visualization during direct laryngoscopy and high upper
43. Adnet F, Boroon SW, Racine SX, et al. The intubation dif- lip bite test scores are predictors of difficult intubation
ficult scale (IDS): proposal and evaluation of a new score with the Glidescope® video laryngoscope. Anesth Analg.
characterizing the complexity of endotracheal intubation. 2008;106:1495–1500.
Anesthesiology. 1997;87:1290–1297. 55. Dufour DG, Larose DL, Clement SC. Rapid sequence
44. Juvin P, Lavaut E, Dupont H, et al. Difficult tracheal intuba- intubation in the emergency department. J Emerg Med.
tion is more common in obese than in lean patients. Anesth 1995;13:705–710.
Analg. 2003;97:595–600. 56. Walls RM. Management of the difficult airway in the trauma
45. Gonzalez H, Minville V, Delanoue K, et al. The importance patient. Emerg Med Clin North Am. 1998;16:45–61.
of increased neck circumference to intubation difficulties in 57. Martin LD, Mhyre JM, Shanks AM, et al. 3,4423 emergency
obese patients. Anesth Analg. 2008;106:1132–1136. tracheal intubations at a university hospital: airway out-
46. Brodsky JP, Lemmens HJ, Brock-Utne JG, et al. Morbid comes and complications. Anesthesiology. 2011;114:42–48.
obesity and tracheal intubation. Anesth Analg. 2002;94: 58. Sakles JC, Laurin EG, Rantapaa AA, et al. Airway manage-
732–736. ment in the emergency department: a one-year study of 610
47. Neligan PJ, Porter S, Max B, et al. Obstructive sleep apnea tracheal intubations. Ann Emerg Med. 1998;31:325–332.
is not a risk factor for difficult intubation in morbidly obese 59. Tayal VS, Riggs RW, Marx JA, et al. Rapid sequence intuba-
patients. Anesth Analg. 2009;109:1182–1186. tion at an emergency medicine residency: success rate and
48. Collins JS, Lemmens HJ, Brodsky JB, et al. Laryngoscopy and adverse events during a two-year period. Acad Emerg Med.
morbid obesity: a comparison of the “sniff” and “ramped” 1999;6:31–37.
positions. Obesity Surg. 2004;14:1171–1175. 60. Walls RM, Gurr DE, Kulkarni RG, et al. 6294 emergency
49. Collins JS, Lemmens HJ, Brodsky JB. Obesity and dif- department intubations: second report of the Ongoing
ficult intubation: where is the evidence? Anesthesiology. National Emergency Airway Registry (NEAR) II study. Ann
2006;104:617. Emerg Med. 2000;36:A196.
50. Cass NM, James NR, Lines V. Difficult direct laryngos- 61. Li J. Capnography alone is imperfect for endotracheal tube
copy complicating intubation for anaesthesia. Br Med J. placement confirmation during emergency intubation.
1956;1:488–489. J Emerg Med. 2001;20:223–239.
51. Khan ZH, Kashfi A, Ebrahimkhani E. A comparison of the
upper lip bite test (a simple new technique) with modified
DESIGN SERVICES OF

CHAPTER
10 Computerized Analysis to
Associate Facial Features with
Difficult Intubation
Christopher W. Connor and Scott Segal
A ll patients undergoing preoperative evaluation are

assessed for anatomic features that might predict
difficulty in performing endotracheal intubation under
used to derive the test,8 and the inadequacy of the tests
themselves. Conversely, experienced anesthetists almost
certainly use cues other than those derived from formal
general anesthesia. Typically, at least two examinations bedside tests to formulate their clinical impression of the
are used: the “Mallampati Test” (MP)1,2 is performed and ease of intubating any given patient. There may be several
the thyromental distance (TMD)3 is measured. The MP anatomic factors that enter into such a judgment.11 The
test involves an examination of oropharyngeal structures development of a tool that is able to capture this gestalt
that are visible when the seated patient maximally opens of the experienced anesthesiologist remains an important,
the mouth and extends the tongue without phonation. The incompletely solved problem.
TMD measures the space between the superior tip of the Suzuki et al12 used digital photographs of subjects’
thyroid cartilage and the inside of the tip of the mandible. faces to calculate five ratios and angles from measure-
Both tests perform only modestly, with sensitivity of 30% ments derived from placement of anatomic markers on
to 60%, specificity of 60% to 80%, and positive predictive the photographs. They found one, the “submandibular
value of just 5% to 20%.4 Even so, the combination of MP angle,” to be correlated with difficult tracheal intubation.
and TMD performed better than any other bedside screen- Similarly, Naguib et al13 measured 22 indices from plain
ing test in a meta-analysis of 35 trials studying over 50,000 radiographs and 8 from three-dimensional computed to-
subjects.4 In practice, anesthesiologists likely weigh other mography scans of the head in patients who were easy or
subjective factors in anticipating a difficult airway, includ- difficult to intubate. They constructed a model containing
ing habitus, facial appearance, and perhaps other poorly three bedside tests (MP, TMD, and thyrosternal distance)
understood hunches. and two radiographic features that accurately separated
Use of a bedside examination to predict difficult the easy and difficult cohorts with an AUC of the re-
intubation is considered the standard of care in modern ceiver operating characteristic (ROC) curve of 0.97. Both
anesthesiology practice. It has been incorporated into the of these previous investigations, however, used a priori
difficult airway algorithm of not only the American Society assumptions of which anatomic features might relate to
of Anesthesiologists (ASA)5 and those of several other difficult laryngoscopy and intubation. Both also required
countries6 but also most recently into the World Health actual measurement of anatomic features.
Organization Surgical Safety Checklist.7 Unfortunately, In contrast, we have proposed a photographic tech-
all easily performed examination systems in clinical prac- nique that models the entire physiognomy of the face
tice perform only modestly, with sensitivities of 20% to with no such assumptions and no direct measurements.14
62%, specificities of 82% to 97%, and very low positive Computer software is used to reconstruct a three-
predictive values, generally less than 30%, unless very dimensional model of the patient’s head from three pho-
liberal definitions of difficulty are used.8 There are likely tographs, as shown in Fig. 10-1. The relative sizes of the
several reasons for this poor performance, including the patient’s facial features can be measured from this model.
relative rarity of difficult intubation,8 the multifactorial Using photographs of patients whose ease or difficulty is
etiology and varying definition of difficult intubation, already known, a statistical decision-making model can be
interobserver variability in test results,9,10 failure to vali- derived that can distinguish those patients who are easy
date potential systems in patients independent of those to intubate from those who are difficult. This statistical
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CHAPTER 10 ■ COMPUTERIZED ANALYSIS TO ASSOCIATE FACIAL FEATURES WITH DIFFICULT INTUBATION 71
model does not contain any a priori assumptions about the easy nor difficult to intubate by these criteria were not
facial features that may prognosticate difficult intubation. recruited.
The statistical model should, without preconditioning, The photographs were analyzed by facial struc-
model the gestalt of the anesthesiologist once sufficient ture analysis software (FaceGen Modeller v3.3, Singular
example cases are provided to it. Inversions, Toronto, Canada), and each face was resolved
In our initial investigation, 80 Caucasian male pa- into 61 facial proportions (Table 10-1). Each parameter
tients were recruited postoperatively. These patients were was tested for discriminatory ability by logistic regres-
defined as easy to intubate if their anesthetic record de- sion,17 and combinations of 11 variables with P ≤ 0.1, plus
scribed a single attempt with a Macintosh 3 blade resulting Mallampati score and TMD, were tested exhaustively by all
in a grade 1 laryngoscopic view (full exposure of the vocal possible binomial quadratic logistic regression models.18
cords).1,15 Difficult intubation was defined by at least one Candidate models were cross-validated by maximizing the
of the following: more than one attempt by an operator product of the area under the ROC19 curves obtained in
with at least 1 year of anesthesia experience, grade 3 or 4 the derivation and validation cohorts.14 The final model
laryngoscopic view on a 4-point scale,15 need for a second was found to depend on only three facial proportions plus
operator, or nonelective use of an alternative airway de- TMD, as marked with asterisks in Table 10-1. Relative to
vice such as a bougie, fiberoptic bronchoscope, or intubat- an androgynous population normal shown in Fig. 10-2,
ing laryngeal mask airway.5,16 Patients who were neither the variations in facial appearance described by the
FIG U RE 10-1 Computer reconstruction of

the head from profile and face-on photographs
(image of first author Christopher W. Connor).
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Table 10-1
The 61 variables defining photographic reconstruction of the head. The TMD and MP test are
included in the table as two further variables that were used for modeling. Those emphasized
demonstrated at least a statistical trend (P ≤ 0.1) with identified difficult intubation. Those marked
with an asterisk appear in the final model.
Descriptive Facial Proportions
Brow ridge—high/low Jaw—retracted/jutting

Brow ridge inner—down/up Jaw—wide/thin
*
Brow ridge outer—up/down Jaw—neck slope high/low
Cheekbones—low/high Jawline—concave/convex
Cheekbones—shallow/pronounced Mouth—drawn/pursed
Cheekbones—thin/wide Mouth—happy/sad
Cheeks—concave/convex Mouth—lips deflated/inflated
Cheeks—round/gaunt Mouth—lips large/small
Chin—forward/backward Mouth—lips puckered/retracted
Chin—pronounced/recessed Mouth—lips thin/thick
Chin—retracted/jutting Mouth—protruding/retracted
Chin—shallow/deep Mouth—tilt up/down
Chin—small/large Mouth—underbite/overbite
Chin—tall/short Mouth—up/down
Chin—wide/thin Mouth—wide/thin
Eyes—down/up Mouth—chin distance—short/long
Eyes—small/large Nose—bridge shallow/deep
Eyes—tilt inward/outward Nose—bridge short/long
Eyes—apart/together Nose—down/up
*
Face—brow-nose-chin ratio Nose—flat/pointed
Face—forehead-sellion-nose ratio Nose—nostril tilt down/up
Face—heavy/light Nose—nostrils small/large
Face—round/gaunt Nose—nostrils wide/thin
Face—tall/short Nose—region concave/convex
Face—up/down Nose—sellion down/up
Face—wide/thin Nose—sellion shallow/deep1
Forehead—small/large Nose—sellion shallow/deep2
Forehead—tall/short Nose—sellion thin/wide
Forehead—tilt forward/back Nose—short/long
*
Head—thin/wide Nose—tilt down/up
Temples—thin/wide
*
TMD MP Test
DESIGN SERVICES OF

F I GUR E 1 0 -2 Appearance of the average head of the reference population.
F I GUR E 1 0 -3 Variations in facial appearance from the average head shown in Figure 10-2 by standard deviations of the
descriptive facial proportions used in the airway algorithm. ␴ is the standard deviation from the normal head derived from 300
individuals.20
three facial proportions used in the model are shown in There are some acknowledged limitations to this
Fig. 10-3. model. First, it is likely that there are causes of difficult in-
As this airway model describes appearance, it is tubation not included in the study cohorts. For example,
possible to generate pictures of faces that would ap- some patients with limited neck mobility but otherwise
pear to have certain degrees of ease or difficulty of normal airways are difficult to intubate.21 Further refine-
intubation. Figure 10-4A illustrates the head that is ment of the model could include subjective or measured
theoretically most difficult to intubate according to the indices of neck extension. Secondly, potentially con-
model. Figure 10-4B represents a head that the model founding racial or gender-based factors were eliminated
would classify as easy to intubate. The parameter val- by confining the model to Caucasian males. Only a large,
ues for this head are set such that the value produced prospective study in a diverse patient population would be
by the model is of the same magnitude but opposite to able to verify the effectiveness of this approach in general
Fig. 10-4A. Figure 10-4B might therefore be considered clinical use. In the study population characterized here,
to represent a patient as easy to intubate as the patient however, computerized facial structure analysis combined
in Fig. 10-4A would be difficult. with a widely used bedside airway evaluation method
DESIGN SERVICES OF

F I GUR E 1 0 -4 A: Appearance of the face rated most difficult to intubate by the model. B: Appearance of a face rated easy to
intubate. The ease is comparable in magnitude to the difficulty associated with Figure 10-4A.
yielded a model that significantly outperformed popular devices to aid the anesthesiologist in their selection in
clinical predictive tests.1,3,14,15 the case of a predicted difficult airway.
In subsequent studies, we have found that human
experts (fully trained experienced anesthesiologists)
cannot match the computer model when presented with REFERENCES
similar data. Conceivably, after validating and perhaps
refining the method based on a prospectively obtained, 1. Mallampati SR, Gatt SP, Gugino LD, et al. A clinical sign
diverse sample, the method could prove useful in the to predict difficult tracheal intubation: a prospective study.
practice of anesthesiology in general, as well as to air- Can Anaesth Soc J. 1985;32:429–434.
way nonexperts. We envision deploying the model over 2. Samsoon GL, Young JR. Difficult tracheal intubation: a ret-
rospective study. Anaesthesia. 1987;42:487–490.
smart phones or other similar devices connected over a
3. Frerk CM. Predicting difficult intubation. Anaesthesia.
network to high-speed computers, evaluating the facial 1991;46:1005–1008.
anatomy and applying the predictive algorithm. Future 4. Shiga T, Wajima Z, Inoue T, et al. Predicting difficult in-
possibilities could include using similar methodology tubation in apparently normal patients: a meta-analysis
to evaluate risk of difficult mask ventilation or rela- of bedside screening test performance. Anesthesiology.
tive utility of various alternative airway management 2005;103:429–437.
DESIGN SERVICES OF

5. American Society of Anesthesiologists Task Force on 14. Connor CW, Segal S. Accurate classification of difficult
Management of the Difficult Airway. Practice guidelines intubation by computerized facial analysis. Anesth Analg.
for management of the difficult airway: an updated report 2011;112:84–93.
by the American Society of Anesthesiologists Task Force 15. Cormack RS, Lehane J. Difficult tracheal intubation in
on Management of the Difficult Airway. Anesthesiology. obstetrics. Anaesthesia. 1984;39:1105–1111.
2003;98:1269–1277. 16. Crosby ET, Cooper RM, Douglas MJ, et al. The unantici-
6. Frova G, Sorbello M. Algorithms for difficult airway man- pated difficult airway with recommendations for manage-
agement: a review. Minerva Anestesiol. 2009;75:201–209. ment. Can J Anaesth. 1998;45:757–776.
7. Haynes AB, Weiser TG, Berry WR, et al. A surgical safety 17. Hosmer DW, Hosmer T, Le CS, et al. A comparison of
checklist to reduce morbidity and mortality in a global pop- goodness-of-fit tests for the logistic regression model. Stat
ulation. N Engl J Med. 2009;360:491–499. Med. 1997;16:965–980.
8. Yentis SM. Predicting difficult intubation—worthwhile ex- 18. Hosmer DW, Lemeshow S. Applied Logistic Regression. 2nd
ercise or pointless ritual? Anaesthesia. 2002;57:105–109. ed. New York, NY: Wiley; 2000.
9. Wilson ME, John R. Problems with the Mallampati sign. 19. Hanley JA, McNeil BJ. The meaning and use of the area
Anaesthesia. 1990;45:486–487. under a receiver operating characteristic (ROC) curve.
10. Karkouti K, Rose DK, Ferris LE, et al. Inter-observer reli- Radiology. 1982;143:29–36.
ability of ten tests used for predicting difficult tracheal intu- 20. Chen TG, Fels S. Exploring gradient-based face navigation
bation. Can J Anaesth. 1996;43:554–559. interfaces. Graphics Interface 2004. ACM International
11. Wilson ME, Spiegelhalter D, Robertson JA, et al. Predicting Conference Proceedings Series 62, 65–72. 2004. Ontario,
difficult intubation. Br J Anaesth. 1988;61:211–216. Canada, Canadian Human-Computer Communications
12. Suzuki N, Isono S, Ishikawa T, et al. Submandible angle Society.
in nonobese patients with difficult tracheal intubation. 21. Santoni BG, Hindman BJ, Puttlitz CM, et al. Manual in-
Anesthesiology. 2007;106:916–923. line stabilization increases pressures applied by the laryn-
13. Naguib M, Malabarey T, AlSatli RA, et al. Predictive models goscope blade during direct laryngoscopy and orotracheal
for difficult laryngoscopy and intubation. A clinical, radio- intubation. Anesthesiology. 2009;110:24–31.
logic and three-dimensional computer imaging study. Can J
Anaesth. 1999;46:748–759.
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CHAPTER
11 New Methods of Bedside

Airway Assessment:
Cone Beam Computed
Tomography, Ultrasound,
and Craniofacial Phenotyping
Jacek Wojtczak and Bo Hu
M ost anesthesiologists predict difficult intubation

based on several bedside preoperative screening
tests. The most popular is establishing the degree of vis-
Craniofacial phenotyping is the newest of the new
methods of bedside airway assessment and requires
three-dimensional (3-D) laser scanning with an auto-
ibility of oropharyngeal structures based on Mallampati mated 3-D rendering10,11 or two-dimensional (2-D) digital
classification,1 measuring thyromental distance (TMD) photography.12
and assessing neck movement and mouth opening.2–4
Unfortunately, all these tests have only modest sensitivity
and specificity in predicting difficult intubation.2–4 Baker CONE BEAM COMPUTED TOMOGRAPHY
et al5 performed the meta-analysis of 24 studies where the
accuracy of TMD measurements was assessed as predic- Cone beam computed tomography (CBCT) is a recent
tor of difficult intubation. The test sensitivity was only advancement in CT imaging, facilitated by parallel ad-
16% when fingerbreadths were used for assessment and vancements in flat panel detectors technology, improved
increased to 48% when the ruler or calipers were used computing power, and the relatively low power require-
for measurements. It implies that the preoperative airway ments of the X-ray tubes used.13,14 The imaging-source
evaluation has to be much more quantitative in order to detector and the method of data acquisition distinguish
be predictive. In this chapter, we will review three mo- CBCT from traditional CT imaging. Traditional CT uses
dalities that potentially may improve preoperative airway a high-output rotating anode X-ray tube, whereas CBCT
evaluation. uses a low-power, medical fluoroscopy tube that provides
MRI and CT are considered gold standards in the continuous imaging throughout the scan. Traditional CT
quantitative, three-dimensional evaluation of the airway. records data with a fan-shaped X-ray beam onto image de-
Both imaging techniques can perform complete volumet- tectors arranged in an arc around the patient, producing a
ric airway analysis,6–8 but MRI has an obvious advantage single slice image per scan. Each slice must overlap slightly
over CT in improved visualization of soft tissues. Both in order to properly reconstruct the images. The advanced
techniques are expensive, hardly bedside, not feasible in CBCT technology uses a cone-shaped X-ray beam that
patients with metal implants (MRI), require long exami- transmits onto a solid-state area sensor for image capture,
nation time (MRI), and expose patients to radiation (CT). producing the complete volume image in a single rotation.
Recently introduced cone beam CT, however, is becoming The sensor contains an image intensifier and a CCD cam-
very popular in the office setting due to its low cost, small era, or an amorphous silicon flat panel detector.
size, very short examination time, and very low level of The single-turn motion image-capture used in CBCT
patient irradiation. is quicker than the traditional spiral motion and can be ac-
Ultrasound (US) of the airway is a bedside imaging complished at a lower radiation dose as a result of no over-
technique that has been used for several years, but the qual- lap of slices. Manufacturers are designing CBCT scanners
ity of US scans of the airway has been generally poor. Recent with the physical space available in clinics and patients’
advances in this technology, availability of high-frequency comfort in mind. Usually, upright seating is used in CBCT
probes, and inexpensive portable US units revived the in- scanners with the X-ray tube and panel detector rotating
terest in this modality as a convenient bedside tool.9 around the patient’s head (Figs. 11-1 and 11-2).
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CHAPTER 11 ■ NEW METHODS OF BEDSIDE AIRWAY ASSESSMENT 77
F I GUR E 1 1 -1 Cone beam computed tomograph (i-CAT) used for imaging of dental implants (courtesy of Eastman Dental
Center, University of Rochester, NY).
A B
F I GUR E 1 1 -2 (A) Sagittal i-CAT CBCT scan: T- turbinates, HP- hard palate, H – hyoid bone, M – mandible, E – epiglottis.
(B) Coronal i-CAT CBCT scan: T- turbinates, HP- hard palate, M – maxilla.
CBCT became a very popular modality in dentistry, practical system to evaluate the upper airway and should
especially implantology. Its value as a clinical tool is also become an excellent research and teaching tool for under-
studied in oral and maxillofacial surgery. As it provides standing the normal and abnormal airway.
not only skeletal but also soft tissue images with an option
of 3-D reconstruction, it may become a very useful tool
in upper airway examination in anesthesiology in patients ULTRASOUND IMAGING
known or suspected to be difficult to intubate. Osorio
et al15 published a preliminary report on the applicability US imaging of the upper airway offers several advantages
of CBCT for the purpose of the clinical airway manage- compared with other imaging techniques. It is widely
ment. They performed 3-D reconstructions of the airway available, portable, repeatable, relatively inexpensive,
as well as “virtual laryngoscopy” by generating “flying pain-free, and safe.9,16–19
through” reconstructions. They found the resulting video The curved array low-frequency (5 MHz) transducers
clips to be of high quality, similar to fiberoptic imaging, (Fig. 11-3) are preferred for submandibular scans to
but without the invasiveness. They concluded that vir- visualize the tongue and the swallowing dynamics.
tual laryngoscopy may be a promising future technique Patients with long hyomental distances may require a
to support clinical anesthesia practice. In their opinion, standoff to enable an accurate measurement of intraoral
CBCT has the potential to emerge as a comprehensive and distances (Fig. 11-4).
DESIGN SERVICES OF

A B
F I GUR E 1 1 -3 A: Midsagittal submandibular sonography using 5 MHz curved array transducer; B: US anatomy of the
suprahyoid region. M, mandibular shadow; H, shadow of the hyoid bone; GH, geniohyoid muscle; MH, mylohyoid muscle;
TS, tongue surface.
A B
F I GUR E 1 1 -4 (A) Standoff gel pad attached to the curved 5 MHz ultrasound probe to enlarge the field of view and improve
visualization of the near field areas (e.g. floor of the mouth). (B) Transverse submandibular scan with the standoff pad presenting
as a hypoechoic space between the surface of the skin and the probe. M – mandible; GH – geniohyoid muscle.
The high-frequency linear probes are useful in imag- a small, high-frequency, curved array transducer in the
ing the superficial structures yielding high-resolution sublingual fossa. Using this approach, they attempted to
scans (Fig. 11-5); however, the US penetration is very poor obtain a longitudinal view of the larynx by placing the
(Fig. 11-6). probe sagittally and longitudinally under the patient’s
It is important to remember that US imaging is in- tongue. Their initial interpretation of the obtained images
direct and often depends on subjective interpretation. was incorrect and had to be retracted.19 Initially, they de-
Recently, Tsui and Hui18 described their initial experi- scribed a dark anechoic structure originally interpreted as
ence of a novel method of US airway imaging by placing the trachea that was later confirmed to be the geniohyoid
DESIGN SERVICES OF

A B
F I GUR E 1 1 -5 Transverse scan of thyroid cartilage and the vocal cords: TC – thyroid cartilage, VL – vocal ligaments,
FC – false cords. Rima epiglottidis marked with crosses.
A B
F I GUR E 1 1 -6 Sagittal scan of the thyrohyoid membrane (THM), hyoid bone (HY), thyroid cartilage (TC), epiglottis (EPI)
and air-mucosa (A-M) interface. Any interface between the mucosa lining the upper airway tract and the air within it has a
bright hyperechoic linear appearance [9].
muscle. The hyperechoic structure originally described Transverse US scanning through the cricothyroid mem-
by them as the epiglottis was later19 confirmed to be the brane allows visualization of the vocal cords (Fig. 11-5)
hyoid cartilage. During swallowing, a dynamic view of el- and their movement during respiration and swallowing.
evation of this distinct hyperechoic structure depicted the Transverse US scanning at the level of the suprasternal
hyoid cartilage being pulled anteriorly by the geniohyoid notch visualizes the hyperechoic thyroid gland and tra-
muscle. Prasad et al20 showed that the transcutaneous US cheal rings (Fig. 11-8).
using a linear, parasagittal scan could visualize the epi- US has been used to assess subglottic diameter21
glottis, which we could also visualize in the midsagittal and to confirm endotracheal tube placement.22 The
plane (Fig. 11-7). echogenicity of the tube was enhanced by retaining a
DESIGN SERVICES OF

A B
F I GUR E 1 1 -7 Sagittal scan over the trachea using a linear transducer. The sonogram shows the cricoid cartilage (CC)
and the tracheal cartilages (TC).
A B
F I GUR E 1 1 -8 Transverse US scan of the thyroid gland (ThG) and tracheal cartilage (TC). T – tracheal lumen,
SM – strap muscles.
stylet in the tube or by the ETT cuff with fluids and air the correct position of the tracheostomy tube after the
bubbles.16 procedure.
Sustic16 described the US-guided percutaneous trache- Sustic16 used US imaging from the lateral neck ap-
ostomy. The site of the puncture was usually selected be- proach to correctly position the laryngeal mask airway.
tween the second and third tracheal rings, after a clear US The proper position of the LMA cuff, especially of its dis-
verification of the anatomy of the thyroid and cricoid car- tal end could be confirmed by US when the cuff was filled
tilage and tracheal rings. The US imaging also confirmed with fluid.
DESIGN SERVICES OF

FIG U RE 11-9 High-resolution

Vivid 900 (Konica Minolta) laser scan-
ner and a portable, lower resolution
laser scanner with an electromagnetic
positioning system (Polhemus FAST
SCAN).
CRANIOFACIAL PHENOTYPING Ratio) and TMD. It correctly classified 70 of 80 subjects

as DTI, whereas the combination of the Mallampati score
The concept of craniofacial phenotyping is based on the and TMD classified only 47 of 80 subjects as DTI.
assumption that certain 2-D or 3-D surface contour mea- Due to the nonlinear nature of human skulls and
surements may be identified as surrogate indicators that faces, simple 2-D photographic linear measurements may
reflect the underlying skeletal structures or soft tissue result in significant errors when performed on curved sur-
oropharyngeal anatomy. Suzuki et al23 performed a systematic faces such as forehead, maxilla, or mandible.27 Moreover,
evaluation of facial appearance of nonobese Japanese 2-D photographic analysis technique may include errors
patients with a history of difficult tracheal intubation (DTI). from subject alignment, camera lens distortion, and pro-
They compared measurements obtained from the fron- jection errors.
tal and profile 2-D digital photographs with the measure- The accuracy of measurements may be greatly im-
ments from the photographs of matched patients with easy proved by using noninvasive, optically based, 3-D digiti-
tracheal intubation (ETI). They found that mandible posi- zation techniques. The most popular 3-D data acquisition
tion was significantly smaller in DTI males than in male technique that has been successfully applied to human fa-
patients with ETI. The submandibular angle was significantly cial measurement is laser surface scanning.10,11 A laser beam
larger in both male and female DTI patients than in patients is swept over the object while a camera mounted inside the
with ETI. The morphing software (see below) was used to scanner records photons reflected from the surface of an
construct “average” and “exaggerated” easy and difficult to object (Fig. 11-9) and generates a set of points in 3-D space
intubate faces. called point cloud and outputs a point cloud as data file.
A study of obstructive sleep apnea (OSA) patients Point clouds themselves are generally not directly usable in
showed that simple measurements from 2-D digital photo- most 3-D applications and therefore usually converted to
graphs can reveal several craniofacial differences between polygonal mesh. Polygonal (usually triangular) mesh forms
subjects with and without OSA.12 The patients with OSA had a wire frame model of an object. A 3-D image of an object is
wider and flatter mid and lower face, shorter jaw, and more created from a model by a process called rendering.
soft tissues on the anterior neck. In a related prospective Because of occlusion, some crucial 3-D features of
cohort study, the same group by using a model with only the face, for example, the angle of the jaw line, cannot
four photographic measurements was able to correctly clas- be obtained from a single frontal scan. Therefore, at least
sify 76% of subjects with OSA.24 As the patients with OSA two extra scans have to be taken, 45° to the right and to
were shown to be difficult to intubate,25 it further confirms the left of the frontal axis (Fig. 11-10). The three scans
the possibility that patients who are difficult to intubate may need to be stitched together to form a full 3-D face image,
also have some characteristic predictive facial features. a process called registration. The Polhemus FAST SCAN
Connor and Segal26 showed that computerized analy- but not the Vivid 900 scanner is able to stitch scans to-
sis of facial structures obtained from the frontal and profile gether automatically in real time due to the electromag-
2-D digital photographs outperformed conventional netic positioning system. The Vivid 900 scanner, however,
airway examination in predicting difficult intubation. Their has a higher resolution than the Polhemus scanner and
model included three facial parameters (Jaw-Neck High/ it also records the color of each pixel, besides its depth
Slope Low; Nose Tilt Down/Tilt Up; Face Brow-Nose-Chin (Fig. 11-9).
DESIGN SERVICES OF

F I GUR E 1 1 -1 0 Merging
of three laser scans to form
a full 3-D face image in a
process called registration.
The face is not blinded
because it is one of the
authors (Bo Hu).
With the registered 3-D face, the anthropometric automatically by applying the morph function on the
measurements can be obtained manually, for example, us- same features defined on the template face (Fig. 11-11).
ing commercial software, but it is tedious and error prone These raw features form the basis of feature vector to the
and not suitable for clinical use. Instead, a template 3-D classification of patients.
face model can be employed. The shape of the model is pa- In our recent study,27 we have compared 3-D cranio-
rameterized by a large group of anthropometric features. facial laser scanning with 2-D photography (Fig. 11-12)
Landmark features, which are prominent and easily and surface measurements as ground truth. We showed
identifiable points on the face (eg, the corners of the eyes, that 3-D craniofacial laser scanning is superior to 2-D
ala nasi), are extracted on both the template face and the photography as it captures the nonlinear nature of cra-
registered face. The template face is then morphed into the niofacial anatomy. Therefore, it may be more sensitive
registered face by interpolating their corresponding land- and specific than 2-D photography in craniofacial phe-
mark points. The morphing is represented as thin-plate notyping of patients with difficult airway and potentially
spline functions, which we call the morph function. The useful in predicting difficult or impossible intubation.
anthropometric features on the patient’s face are obtained Craniofacial 2-D photographic analysis techniques allow
DESIGN SERVICES OF

F I GU R E 11 - 11 Computing anthropometric features. A warp function is computed from the landmarks (marked in red)
matched between a registered face and the template face. The anthropometric features defined on the template face are
transferred by the warp function.
DESIGN SERVICES OF

Table 11-1
Surface (S) and Linear (L) Distances between Anthropometric Points of the Normal and
Obese Clay Head
Actual (S) (mm) 3-D (S) (mm) 3-D (L) (mm) 2-D (L) (mm)
Head—Normal
T-N (L) 102.8 101.7 93.2 88.6
T-SN (L) 108.5 107.8 98.5 97.2
T-GN (L) 122.5 121.2 114.8 110.6
T-GO (L) 49.3 51.6 48.8 51.3
Head—Obese
T-N (L) 104.3 104.1 92.5 78.8
T-SN (L) 113.1 108.3 96.2 84.1
T-GN (L) 135.2 136.5 122.9 106.7
T-GO (L) 69.3 68.7 69.3 73.8
Abbreviations: T, tragion; N, nasion; SN, subnasion; GN, gnathion; GO, gonion.
A B
F I GUR E 11 -1 2 Comparison of 3-D craniofacial laser scanning (A) with 2-D photography (B) and surface measurements (B).
the measurements of linear distances between projections compared with the surface distances. The 2-D versus 3-D
of the anthropometric points into the monoplanar plane. difference was especially large in abnormal heads suggest-
Depending on the location of these points in the 3-D space, ing that only 3-D laser scanning may yield accurate results
these measurements may underestimate the true distance in patients with abnormal head and neck anatomy (eg,
(Fig. 11-13). By comparing linear measurements obtained morbid obesity).
by the 3-D laser scanning and 2-D digital photography, The studies cited above have been performed either
we showed that this error can be as high as 30% of the in the population of nonobese Japanese23 or in selected
actual distance (Table 11-1) and it is even higher when groups of male Caucasians.26 Because obesity is more
DESIGN SERVICES OF

F I GUR E 1 1 -1 3 Laser scans of life-size normal (A) and abnormal (B) clay heads processed using specialized software that has
allowed detailed and highly accurate curvilinear and volumetric craniofacial measurements.
T, tragion; N, nasion; SN, subnasion; GO, gonion; GN, gnathion
common in North America, only a large study in a diverse 5. Baker PA, Depuydt A, Thompson JM. Thyromental dis-
patient population with the use of 3-D scanning can con- tance measurements—fingers don’t rule. Anaesthesia.
firm the validity of the proposed models and the whole 2009;64:878–882.
concept of craniofacial phenotyping. 6. Schwab RJ, Pasirstein M, Mackley A, et al. Identification
of upper airway anatomic risk factors for obstructive sleep
apnea with volumetric magnetic resonance imaging. Am J
Respir Crit Care Med. 2003;168:522–530.
REFERENCES 7. Ryan CF, Lowe AA, Li D. Three-dimensional airway com-
puted tomography in obstructive sleep apnea. Am Rev Resp
1. Mallampati SR. Clinical sign to predict difficult tracheal in-
Dis. 1991;144:428–432.
tubation (hypothesis). Can Anesth Soc J. 1983;30:316.
8. Vos W, De Backer J, Devolder A, et al. Correlation between
2. Ghatge S, Hagberg CA. Does the airway examination pre-
severity of sleep apnea and upper airway morphology based
dict difficult intubation? In: Fleisher LA, ed. Evidence-Based
on advanced anatomical and functional imaging. J Biomech.
Practice of Anesthesiology. Philadelphia, PA: Saunders; 2009.
2007;40:2207–2213.
3. Shiga T, Wajima Z, Inoue T, Sakamoto A. Predicting difficult
9. Singh M, Chin KJ, Chan VWS, et al. Use of sonography for
intubation in apparently normal patients. Anesthesiology.
airway assessment. J Ultrasound Med. 2010;29:79–85.
2005;103:429–437.
10. Kau CH, Richmond S, Zhurov AI, et al. Reliability of
4. Cattano D, Panicucci E, Paolicchi A, et al. Risk factors as-
measuring facial morphology using a 3-dimensional
sessment of the difficult airway: an Italian survey of 1956
laser scanning system. Am J Orthod Dentofacial Orthop.
patients. Anesth Analg. 2004;99:1774–1779.
2005;128:424–430.
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11. Toma AM, Zhurov A, Playle R, et al. Reproducibility of 21. Lakhal K, Deplace X, Cottier JP, et al. The feasibility of
facial tissue landmarks on 3D laser-scanned facial images. ultrasound to assess subglottic diameter. Anesth Analg.
Orthod Craniofac Res. 2009;12:33–42. 2007;104:611–614.
12. Lee RW, Chan AS, Grunstein RR, et al. Craniofacial phe- 22. Werner SL, Smith CE, Goldstein JR, et al. Pilot study to
notyping in obstructive sleep apnea—a novel quantitative evaluate the accuracy of ultrasonography in confirming
photographic approach. Sleep. 2009;32:37–45. endotracheal tube placement. Ann Emerg Med. 2007;49:
13. Miracle AC, Mukherji SK. Conebeam CT of the head 75–80.
and neck, part 1: physical principles. Am J Neuroradiol. 23. Suzuki N, Isono S, Ishikawa T, et al. Submandible angle
2009;30:1088–1095. in nonobese patients with difficult tracheal intubation.
14. Miracle AC, Mukherji SK. Conebeam CT of the head Anesthesiology. 2007;106:916–923.
and neck, part 2: clinical applications. Am J Neuroradiol. 24. Lee RW, Chan AS, Grunstein RR, et al. Prediction of ob-
2009;30:1285–1292. structive sleep apnea with craniofacial photographic analy-
15. Osorio F, Perilla M, Doyle DJ, et al. Cone beam computed sis. Sleep. 2009;32:46–52.
tomography: an innovative tool for airway assessment. 25. Hiremath AS, Hillman DR, James AL, et al. Relationship
Anesth Analg. 2008;106:1803–1807. between difficult tracheal intubation and obstructive sleep
16. Sustic A. Role of ultrasound in the airway management of apnea. Br J Anaesth. 1998;80:606–661.
critically ill patients. Crit Care Med. 2007;35:S173–S177. 26. Connor CW, Segal S. Accurate classification of difficult
17. Shih JY, Lee LN, Wu HD, et al. Sonographic imaging of tra- intubation by computerized facial analysis. Anesth Analg.
chea. J Ultrasound Med. 1997;16:783–790. 2011;112:84–93.
18. Tsui BC, Hui CM. Sublingual airway ultrasound imaging. 27. Wojtczak JA, Bo Hu. Anthropometric analysis of abnormal
Can J Anesth. 2008;55:790–791. craniofacial morphology: 2D photography versus 3D laser
19. Tsui BC, Hui CM. Challenges in sublingual airway ultra- scanning. Proceedings 2010 ASA Annual Meeting, abstract
sound interpretation. Can J Anesth. 2009;56:393–394. A1171.
20. Prasad A, Singh M, Chan V. Ultrasound imaging of the
airway. Can J Anaesth. 2009;56:868–870.
DESIGN SERVICES OF

CHAPTER
Decision Making in Difficult

Airway Management
12 cn
Tara Knizner and Cynthia Wells
M anagement of the airway is one of the primary

responsibilities of anesthesiologists and physicians
caring for critically ill patients. There are multiple clinical
are encountered with securing the airway. Table 12-2 lists
techniques for management in these situations.1
One of the greatest challenges in airway management
scenarios in which intubation of the trachea is indicated. is the patient who does not demonstrate the above charac-
In the operating room, intubation is necessary in order to teristics but presents difficulty in ventilation or intubation
ensure patency and protection of the airway in a patient after being rendered unconscious. Therefore it is the re-
rendered unconscious by anesthesia. When a patient is in sponsibility of the anesthesiologist OR OTHER AIRWAY
acute respiratory distress or requires resuscitation, there PROVIDER to always be prepared to manage the unantici-
is a requirement to maintain oxygenation and ventilation. pated difficult airway. Prior to the induction of every an-
Complications related to airway management are one esthetic, various airway tools should be readily available,
of the most frequently cited adverse outcomes associated including multiple rigid laryngoscope blades of various
with anesthetic delivery. These complications include sizes, a gum elastic bougie, oral airways, laryngeal mask
death, brain injury, unnecessary tracheostomy, airway airways (LMAs), a 14G angiocatheter, and a functional
trauma, and damage to teeth (see Chapter 55).1 Many of manual jet ventilator.
these catastrophic outcomes result from inability to secure If an attempt at intubation after induction of anes-
the airway during attempts at management of difficult ven- thesia is undertaken in a patient who has an airway exam
tilation and/or intubation. In order to standardize man- that is less than ideal, the anesthesiologist should have ad-
agement of the difficult airway, practice guidelines were ditional tools for airway management immediately avail-
developed by the American Society of Anesthesiologists able. These, may include a rigid fiberoptic laryngoscope
(ASA) Task Force in 1993 and later revised in 2003. Since (eg, Glidescope), a fiberoptic bronchoscope, AN intu-
their implementation in the United States, morbidity, bating LMA, A lightwand or a difficult airway cart that is
mortality, and claims related to airway management in the equipped with various tools that can be used in the event
operating room have fallen significantly.2 of difficulty with intubation. The importance of being
When following the ASA Difficult Airway Algorithm, familiar with these tools and having them immediately
the two primary components of the initial patient assess- available in the event of an unanticipated difficult airway
ment involves determining whether one may face difficulty cannot be overstated because prediction of the difficult
with mask ventilation or tracheal intubation. As described airway is unreliable.
in the previous chapter, there are multiple physical crite- The ASA difficult airway algorithm specifically ad-
ria used by physicians to identify patients that are at high dresses the course of action to take in the event a diffi-
risk (see Table 12-1).1 Additional consideration must be cult airway is encountered after the induction of general
given to whether the patient may have difficulty cooper- anesthesia (Fig. 12-1).1 If initial attempts to intubate the
ating with awake attempts at intubation or whether one patient are unsuccessful, then the anesthesiologist should
may face a difficult tracheostomy in an emergency setting. consider calling for help, returning the patient to sponta-
Furthermore, the airway examination may reveal the pres- neous ventilation, and/or allowing him/her to awaken pro-
ence of severe airway anatomy or pathology that warrants vided that a short-acting anesthetic and muscle relaxants
an initial surgical approach. Other management options have been administered. The ability to call for assistance
include maintenance of spontaneous ventilation versus varies depending on the type of institution in which the
attempting intubation after the induction of general an- anesthesiologist is practicing as well as the time of day.
esthesia. Most often, if it is determined that there would This situation changes dramatically if the anesthesiologist
be difficulty with ventilation or intubation, the option of is the lone provider or is on call at night where he/she may
an awake intubation is considered for the cooperative pa- be the only trained airway provider available. Similarly,
tient in order to maintain spontaneous ventilation. This intensivists, hospitalists, and emergency physicians who
technique increases the threshold of safety if problems provide airway management services may find themselves
87

Table 12-1
Components of the Preoperative Airway Physical Examination
Airway Examination Component Nonreassuring Findings

1. Length of upper incisors Relatively long
2. Relation of maxillary and mandibular incisors during Prominent “overbite” (maxillary incisors anterior
normal jaw closure to mandibular incisors)
3. Relation of maxillary and mandibular incisors during Patient mandibular incisors anterior to (in mandible
voluntary protrusion of cannot bring front of) maxillary incisors
4. Interincisor distance < 3 cm
5. Visibility of uvula Not visible when tongue is protruded with patient
in sitting position (eg, Mallampati class greater than II)
6. Shape of palate Highly arched or very narrow
7. Compliance of mandibular space Stiff, indurated, occupied by mass, or nonresilient
8. Thyromental distance Less than three ordinary finger breadths
9. Length of neck Short
10. Thickness of neck Thick
11. Range of motion of head and neck Patient cannot touch tip of chin to chest
or cannot extend neck
This table displays some findings of the airway physical examination that may suggest the presence of a difficult intubation. The decision to examine
some or all of the airway components shown in this table depends on the clinical context and judgment of the practitioner. The table is not intended
as a mandatory or exhaustive list of the components of an airway examination. The order of presentation in this table follows the “line of sight” that
occurs during conventional oral laryngoscopy.
From Practice guidelines for management of the difficult airway: an updated report by the ASA task force on management of the difficult airway.
Anesthesiology. 2003;98:1269–1288, with permission.
Table 12-2
Techniques for Difficult Airway Management
Techniques for Difficult Intubation Techniques for Difficult Ventilation

Alternative laryngoscope blades Esophageal tracheal Combitube
Intratracheal jet stylet
Awake intubation LMA
Blind intubation (oral or nasal) Oral and nasopharyngeal airways
Rigid ventilating bronchoscope
Fiberoptic intubation Invasive airway access
Intubating stylet or tube changer Transtracheal jet ventilation
Two-person mask ventilation
LMA as an intubating conduit
Lightwand
Retrograde intubation
Invasive airway access
This table displays commonly cited techniques. It is not a comprehensive list. The order or presentation is alphabetical and does not imply pref-
erence for a given technique or sequence of use. Combinations of techniques may be employed. The techniques chosen by the practitioner in a
particular case will depend upon specific needs, preferences, skills, and clinical constraints.
Anesthesiology. 2003;98:1269–1288, with permission.
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CHAPTER 12 ■ DECISION MAKING IN DIFFICULT AIRWAY MANAGEMENT 89
F I GU R E 12 - 1 ASA difficult airway management algorithm.

(From Practice guidelines for management of the difficult airway: an updated report by the ASA task force on
management of the difficult airway. Anesthesiology. 2003;98:1269–1288, with permission.)
DESIGN SERVICES OF

unable to call upon “back up” because the settings and emergency. In addition, other support staff may be trained
times of day that are involved often preclude this. to obtain difficult airway equipment during these situa-
After multiple attempts to intubate via direct laryn- tions. The contents of difficult airway carts are fairly stan-
goscopy have been unsuccessful (typically this should be dard throughout most institutions, and they should con-
limited to three or four attempts), the anesthesiologist tain all of the necessary equipment to assist in establishing
must attempt to ventilate the patient via face mask. If face an airway. Table 12-3 lists the recommended contents of
mask ventilation is adequate, then the situation is consid- these carts, according to the ASA guidelines.1
ered nonemergent and alternative noninvasive approaches Another aspect of the program includes standardized
can be attempted such as the use of different laryngoscope training in difficult airway management for all anesthesia
blades, LMA as an intubation conduit, fiberoptic intuba- personnel on a regular basis. Many institutions use simula-
tion, intubating stylet, lightwand, or retrograde intubation situations for training purposes (see Chapter 13, 14).
tion. If one continues to encounter difficulties, adequate Commonly, this involves a simulation mannequin and a
oxygenation must be maintained via face mask ventilation staged scenario in which multiple anesthesia personnel
in between attempts. manage the difficult airway. Various studies have been
When a patient cannot be ventilated by face mask, conducted to examine the efficacy of simulation training
one has entered the emergent pathway of the difficult on adherence to the ASA difficult airway algorithm. Some
airway algorithm. In these emergent instances, the an- of these have shown simulation to be useful in training of
esthesiologist must call for help and then attempt emer- management of emergency situations in anesthesia3,4 and
gency ventilation-preferably using an LMA, although as a tool to reinforce algorithms for anesthesia residents.5
an esophageal-tracheal combitube or transtracheal jet However, one recent study illustrated that in a group of
ventilation may also be utillized (chapters 25, 26, 29). experienced anesthesiologists, despite simulation train-
Because of its ease of insertion, rapid establishment of ing, there was incomplete adherence to the ASA algorithm
ventilation, familiarity to anesthesia personnel, and during a repeated simulation of a cannot intubate, can-
reliability in this setting, the LMA was emphasized as not ventilate scenario.6 In a recent retrospective database
the preferred instrument for emergent ventilation when review conducted at Johns Hopkins University School of
bag-mask ventilation fails, in the 2003 ASA guidelines.1 Medicine, it was determined that a comprehensive diffi-
If the patient can be oxygenated by one of these ap- cult airway program reduced the need for emergency sur-
proaches, a decision must then be made to either allow gical airways. It was determined that despite an increase in
the patient to emerge from anesthesia and resume spon- the number of patients reported to have a difficult airway
taneous ventilation, to proceed with surgery using the and an overall increase in the number of patients receiving
above airway technique such as the LMA, or to establish anesthesia that the incidence of emergency surgical airway
a definitive airway. A definite airway may be indicated procedures decreased after institution of a comprehensive
for emergency surgery, to prevent aspiration, or if the difficult airway program.7 Finally, with the implementa-
above technique is not adequate for long-term ventilation of electronic medical records, many institutions have
tion. Attempts to establish a definitive airway in these the option of documenting whether a patient has a known
situations may include such techniques as passing an difficult airway. This allows the practitioner to adequately
endotracheal tube through an LMA with or without prepare for the management of the airway, which may in-
fiberoptic guidance or performing a fiberoptic oral involve performing an awake intubation.
tubation during jet ventilation. If these attempts fail or Although most situations requiring airway manage-
if the patient’s condition deteriorates further, invasive ment occur in the controlled environment of the operat-
airway access must be established BY EITHER emergent ing room suite, management of the airway in other areas
tracheostomy or cricothyrotomy by open or percutane- of the hospital provides additional challenges. Many pa-
ous approaches (chapters 36 through 39). In the operat- tients present to the emergency department as a result
ing room, trained surgical personnel are often available of trauma or respiratory failure, and these patients often
to perform the emergency invasive airway. require emergent intubation. Table 12-4 lists the differ-
Many institutions have implemented a comprehensive ences between an emergent and nonemergent airway.
program designed to address management of the difficult Often the circumstances associated with an emergent
airway. In these institutions, there are certain standard airway can increase the likelihood of morbidity to the
procedures performed in the event that a difficult airway patient. For example, in an emergent intubation, there
is unexpectedly encountered. For example, as cited in the is no time to adequately preoxygenate a patient as the
difficult airway algorithm, one of the first steps in dealing preparatory time to intubation is seconds rather than
with a difficult airway is calling for help. This is usually ac- minutes. The patient often is breathing room air (FiO2 =
complished via a code button in the operating room suite 21%) prior to apnea as opposed to 100% oxygen. This
or an overhead airway paging system in order to notify decreases the apneic time to desaturation making it nec-
trained anesthesia personnel of the location of an airway essary to intubate the trachea quickly. Unlike patients
DESIGN SERVICES OF

Table 12-3
Suggested Contents of the Portable Storage Unit for Difficult Airway Management
1. Rigid laryngoscope blades of alternate design and size from those routinely used; this may include a rigid fiberoptic
laryngoscope
2. Tracheal tubes of assorted sizes
3. Tracheal tube guides. Examples include (but are not limited to) semirigid stylets, ventilating tube changer,
lightwands, and forceps designed to manipulate the distal portion of the tracheal tube
4. LMAs of assorted sizes; this may include the intubating LMA and the LMA-Proseal (LMA North America, Inc.,
San Diego, CA)
5. Flexible fiberoptic intubation equipment
6. Retrograde intubation equipment
7. At least one device suitable for emergency noninvasive airway ventilation. Examples include (but are not limited
to) an esophageal tracheal Combitube (Kendall-Sheridan Catheter Corp., Argyle, NY), a hollow jet ventilation
stylet, and a transtracheal jet ventilator
8. Equipment suitable for emergency invasive airway access (eg, cricothyrotomy)
9. An exhaled CO2 detector
The items listed in this table represent suggestions. The contents of the portable storage unit should be customized to meet the specific needs,
preferences, and skills of the practitioner and health care facility.
Anesthesiology. 2003; 98:1269–1288, with permission.
Table 12-4
Differences in Airway Management Requirements between Elective operating room Cases and
Emergency Situations
Aspects of Airway Management Elective Cases in Operating Room Emergent Cases

Goals Assure patent airway and ventilation Obtain definitive airway,
while patient is unconscious ensure ongoing ventilation and
oxygenation, control secretions
Patient Respiratory system intact Respiratory failure common
Characteristics Fasted Presumed full stomach
Preparatory time Hours to days Seconds to minutes
Alternatives for failed airway Emphasis on awakening patient to allow Must progress to definitive airway
resumption of spontaneous ventilation
scheduled for an elective procedure who have fasted for spine stabilization during intubation, which can make
8 hours or more, the patients presenting to the trauma it difficult to align the oral, pharyngeal, and laryngeal
bay are considered to have a full stomach and are treated axis, limiting the view of the glottic opening. In addition,
with precautions such as cricoid pressure (i.e., Sellick the view of the vocal cords can be further limited by the
maneuver) and rapid sequence intubation in order to presence of blood and/or secretions in the pharynx. See
minimize the risk of pulmonary aspiration of gastric Figure 12-2 for one example of an airway management
contents. Patients involved in trauma require cervical algorithm used by emergency physicians.8
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F I GUR E 1 2 -2 Emergency medicine airway

management algorithms. A: Routine airway
management algorithm. B: Algorithm for
“crash airway” when there is no time for
patient assessment or preparation and the
need for an airway is emergent.
C: Algorithm for predicted difficult ventilation
and/or intubation. D: Algorithm for “failed
airway” when intubation by attempted direct
laryngoscopy could not be accomplished.
(From Walls RM, ed. Manual of Airway
Management. 2nd ed. Philadelphia, PA:
Lippincott Williams & Wilkins; 2004:8–21,
with permission).
DESIGN SERVICES OF

DESIGN SERVICES OF

F I GUR E 1 2 -2 (Continued)
DESIGN SERVICES OF

REFERENCES management strategies and skill retention. Anaesthesia.

2008;63:364–369.
1. Caplan RA, Benumof JL, Berry FA, et al. Practice guide- 5. Schaefer JJ III. Simulators and difficult airway management
lines for management of the difficult airway. Anesthesiology. skills. Paediatr Anaesth. 2004;14:28–37.
2003;98:1269–1288. 6. Borges B, Boet S, Siu L, et al. Incomplete adherence to
2. Peterson GN, Domino KB, Caplan RA, et al. Management of the ASA difficult airway algorithm is unchanged after a
the difficult airway: a closed claims analysis. Anesthesiology. high-fidelity simulation session. Can J Anesth. 2010;57(7):
2005;103:33–39. 644–649.
3. Chopra V, Gesink BJ, de Jong J, et al. Does training on an 7. Berkow L, Greenberg R, Kan K, et al. Need for emergency
anaesthesia simulator lead to improvement in performance? surgical airway reduced by a comprehensive difficult airway
Br J Anaesth. 1994;73:293–297. program. Anesth Analg. 2009;109:1860–1869.
4. Kuduvalli PM, Jervis A, Tighe SQ, et al. Unanticipated 8. Walls RM. The emergency airway algorithms. In: Walls
difficult airway management in anaesthetised patients: a RM, ed. Manual of Emergency Airway Management. 3rd ed.
prospective study of the effect of mannequin training on Philadelphia, PA: Lippincott William & Wilkins; 2008:9–21.
DESIGN SERVICES OF

CHAPTER
13 Training in Airway
Management: Difficult Airway
Simulation
Scot Muir and Joseph Quinlan
A difficult airway is defined by the American Society

of Anesthesiologists (ASA) as “the clinical situation
in which a conventionally trained anesthesiologist experi-
training include (1) improved safety to the patient, (2)
the ability for increased exposure to unlikely or rare
scenarios, (3) the ability to manipulate and customize
ences difficulty with face mask ventilation of the upper those scenarios, and (4) decreased incidence of malprac-
airway, difficulty with tracheal intubation, or both.”1 tice claims.7
A mismanaged difficult airway is often an immediate threat There are several concerns that must be addressed
to the patient’s life. Therefore, it is essential for all anes- before any simulation program can be accepted as a suit-
thesiologists to be experts in difficult airway management able tool for teaching DAM and measuring competence
(DAM). Although analysis of the ASA closed claim data- in DAM. The chief concern is validation, that is, does the
base suggests that implementation of the ASA DAM algo- simulation program truly measure what it purports to
rithm over the past two decades has reduced the number measure? Can the simulation environment reproduce the
of failed difficult airways during induction of anesthesia,2 events normally encountered in the clinical arena? Do
outcomes in simulated DAM indicate that a significant the tools used clinically function in the expected way in
percentage of currently practicing anesthesiologists are the simulation environment? Does the simulation program
poor managers of the difficult airway, with up to a third of define competence in a way that most experts in the field
simulated emergent pathway airways ending in simulated would endorse? Can it reliably discriminate between an
death.3,4 There are two factors that probably contribute to expert and a novice? Is the measurement of competence in
this lack of expertise. First, the ACGME requirements for a given subject reproducible over repeated measures? How
training in DAM during residency are remarkably non- long does the effect of the training and measurement last
specific,5 and there are understandably a wide variety of (ie, retention)? These concepts are vital in assessing the
approaches to teaching management of the difficult air- effectiveness of any educational program, but particularly
way. Second, DAM is not an everyday occurrence. It has so in the field of simulation which has been plagued in
been estimated that encountering a difficult airway is a the past by a relative lack of effectively validated studies.8
relatively rare event. In one particular study, there were Fortunately, validity has been shown to be high in
100 out of 11,257 unanticipated difficult intubations.6 regard to many aspects of DAM simulation. The primary
Difficult ventilation, however, seemed even more rare factor responsible for this is the existence of the ASA Diffi-
with 6 of 11,257 being difficult but 0 of 11,257 being clas- cult Airway Algorithm, which provides a peer-reviewed
sified as impossible ventilations.6 It may be difficult for gold standard for the management of the difficult airway.
many anesthesiologists to gain enough experience to be- It has been shown that DAM simulation courses seem
come and remain expert difficult airway managers based to have high correlation with clinical scenarios.9,10 This
solely on their residency training and clinical experience. is probably because most scenarios are based on events
Thus, it is imperative for the anesthesiologist to receive that have occurred in the clinical realm. It has also been
additional training in DAM beyond everyday clinical shown that there is high validity of the actual specific air-
experience. way techniques for the Laerdal Simman.11 The validity of
Simulation provides experience to the learner in a DAM simulation is not confined just to anesthesiology but
more controlled and structured environment than is pos- also appears to extend to other medical specialties as well
sible in the clinical arena. Simulation of the difficult air- as to prehospital providers.12,13 Finally, it appears that vari-
way is in many respects the most ideal method to learn ous DAM courses that are designed with a structured cur-
DAM. Advantages of simulation as opposed to in vivo riculum produce similar results.12,13
96

CHAPTER 13 ■ TRAINING IN AIRWAY MANAGEMENT: DIFFICULT AIRWAY SIMULATION 97
Reliability has also been shown to be very high for “working” knowledge of the ASA difficult airway algorithm,
DAM simulation. There has been significant intratrainee (2) develop confidence and proficiency in performing the
reproducibility within a DAM simulation course.14 DAM various difficult airway techniques, and (3) develop exper-
simulation can reliably discriminate between experienced, tise and confidence in applying the ASA difficult airway
competent airway managers and novices who would not algorithm through managing simulated difficult airway
be expected to be competent.9 scenarios in real time. Each DAM scenario then has its
The question of how long DAM skills taught using own, more specific objectives.
simulation are retained remains unanswered and will re- The entire curriculum of the course is posted online,
quire additional research. Early data suggested that DAM and participants are expected to review the material prior
skills taught via simulation were reasonably well main- to attending the course. Prior review is assessed using a
tained at 1 to 3 years after initial training.15 Other recent short quiz at the beginning of the course. Participants
data, however, showed that it may be necessary to repeat then perform four simulated airway scenarios that assess
DAM simulation every 6 months or less.16 This data showed their ability to apply the ASA difficult airway algorithm in
that skills acquired for cannot intubate/cannot ventilate real time. This provides a baseline assessment of the par-
were retained for approximately 6 to 8 months, but the ticipant’s strengths and weaknesses prior to any training.
skills acquired for cannot intubate were only retained for Feedback and discussion about the participant’s perfor-
6 to 8 weeks.16 Length of retention is likely related to how mance is provided after the completion of the scenarios.
often the anesthesiologist encounters the difficult airway Following the baseline assessment scenarios, the
in daily clinical practice. instructor delivers a short didactic lecture. The lecture
As simulation has become more widely accepted reviews basic science concepts such as the time course of
as a vital tool for teaching and assessing DAM, more oxyhemoglobin desaturation during apnea, anatomy of
of the most prestigious anesthesiology residencies are the airway, and the structure of ASA difficult airway
implementing structured simulation courses in DAM for algorithm. The core of the course consists of an in-depth
residency training. In addition, the American Board of review of all of the tools approved for use within the ASA
Anesthesiology has recognized DAM simulation as one of difficult airway algorithm (laryngeal mask airway, intu-
the core areas eligible for its Maintenance of Certification bating laryngeal mask airway, Combitube, transtracheal
in Anesthesiology program and is working with the ASA jet ventilation, cricothyrotomy, percutaneous cricothyrot-
Simulation Network to increase opportunities for practic- omy, retrograde intubation, lighted stylet, and fiberoptic
ing anesthesiologists to obtain additional simulation train- bronchoscopy) as well as several that are not yet included
ing in DAM.17 in the algorithm (video laryngoscopy, tube exchangers).
At UPMC, the Winter Institute for Simulation, Edu- This is accomplished using short video clips coupled with
cation, and Research (WISER) plays a vital role in train- an extended skill practice session on the mannequin simu-
ing residents, fellows, and attending physicians in DAM. lators. Participants are encouraged to practice use of each
There are three courses that share a basic curriculum and airway tool to the point that they are confident that they
format but in which the specific simulation scenarios could use them in a patient the next day. Once partici-
are tailored to the specialties in which DAM is crucial. pants are confident of their ability to use the individual
These specialties included are anesthesiology, critical care airway techniques, they then practice DAM scenarios until
medicine, and emergency medicine. The courses taught they are confident of their ability to apply the ASA difficult
to anesthesia and critical care medicine (CCM) providers airway algorithm in real time. The DAM course then ends
are very similar, whereas the DAM course taught to em- with four scenarios that again assess the management of
ergency medicine physicians focuses on how to quickly various difficult airway situations. Tables 13-2 and 13-3
assess an airway and how the difficult airway applies to show sample scenarios a participant may be trained on.
rapid sequence intubation. All courses are structured ar- Table 13-2 shows the information the participant has ac-
ound the ASA Difficult Airway Algorithm. Our residency cess to and Table 13-3 shows the information that the in-
has required that all anesthesiology residents attend the structor has access to. Figures 13-1 and 13-2 show the
Anesthesiology DAM course each year during their CA-1 corresponding monitors and computer simulation control
through CA-3 years, for more than a decade. All anesthesi- that accompanies each scenario. Figure 13-1 is the moni-
ology faculty at UPMC must complete the Anesthesiology tor the participant sees during the case and which vital
DAM simulation prior to being granted medical staff privi- signs change in response to how they manage the scenario.
leges in anesthesiology. Figures 13-2, 11-3, and 13-4 show the screen view that the
We will focus on the DAM course for anesthesiolo- instructor has and is able to manipulate based on the ac-
gists (Table 13-1 for outline) and present a sample sim- tions of the participant. A simulator with scripting allows
ulation scenario. The objectives of the Anesthesiology those who are not experts in simulation to easily and reli-
DAM course are for each participant to (1) develop a ably administer simulated airway scenarios.
DESIGN SERVICES OF

Table 13-1
An Outline for the Progression of a DAM Simulation Course
Outline of Course
1. Establish objectives
2. Scenarios—baseline
3. Feedback on scenario performance
4. Didactics
a. Basic science concepts
b. Airway assessment
c. ASA algorithm
5. DAM tools/techniques—LMA, Combitube, FOB
a. Didactics
b. Practice on simulator
6. Scenario—assessment
Table 13-2
Sample Scenario: The Information the Participant is Given at the Beginning of a Simulation Scenario
Sample Airway Scenario: Unanticipated Difficult Airway after Induction of General Anesthesia for Emergent
Caesarian Section
Participant Information
Setting: You are the lone anesthesia caregiver on call at a small town rural hospital. At 1 in the
morning you are asked to emergently provide a general anesthetic for a young female
for a stat c-section.
Patient: The patient is a 25-y-old female with preeclampsia who has a decreased fetal heart
rate (80) for 4 min.
History: PMH: G2 P1 with preeclampsia with current pregnancy
PSH: Tonsillectomy at 5 y.o. GA without reported complications
MEDS: Nubain 5 mg i.v. q2h prn pain
ALLERG: NKDA
NPO: 14 h
ROS: neg. tob/Etoh, neg. cardio-pulm., neg. hepato-renal
PE: 5⬘6⬙, 85 kg, temp. 37°C, BP 180/95, lungs-CTA, cor- RRR
LABS: plt 40,000, HCT 38, K 4.0, bleeding time 3 min (normal 1–2.5)
Associated information: The surgeon wishes to begin this emergent c-section ASAP.
Equipment available: • Macintosh/Miller blades
• Fiberoptic bronchoscope
• LMA/Fastrack LMA
• Esophageal-tracheal Combitube
• TTJV
• Cricothyrotomy kit
• Lighted stylet
• Retrograde kit
• Gum bougie
• ETT exchangers
• Various oral and nasal airways
Written by: David Metro, MD for WISER DAM Simulation Course.
DESIGN SERVICES OF

Table 13-3
Sample Scenario: The Information the Instructor has Access to and is Able to Manipulate.
There are Specific Criteria for the Instructor to Follow Based on the Actions of the Trainee
Instructor Information
Facilitator Guidelines for Sample Scenario: Unanticipated Difficult Airway after Induction of General Anesthesia
for Emergent Caesarian Section
Scenario Objectives:
1. Appropriately recognize that this scenario immediately leads to the “Emergent Pathway.”
2. Consider returning to spontaneous ventilation.
3. Consider awakening the patient but realize that the patient is desaturating too fast for this strategy to work.
4. Call for appropriate help and equipment.
5. Identify the appropriate options for emergency airway ventilation.
6. Demonstrate effective psychomotor skill sets applying these options.
7. Identify the appropriate options for emergency surgical airway ventilation.
8. Demonstrate effective psychomotor skill sets applying these options.
Overview:
The patient is a young, previously healthy, female who presents for an emergent cesarean section. Induction of anesthesia
will lead to a “cannot intubate, cannot ventilate” emergency. After induction, she will die within 5 min if an airway is not
obtained. The scenario is geared toward obtaining an emergency surgical airway, though proper TTJV will also succeed.
General type of case:
Cannot intubate, cannot ventilate, 5 min desaturation, only TTJV and cricothyrotomy will work.
Simulator Setup:
Standard Prep, hand jet vent. flow control turned off (the trainee should be expected to check this).
Airway History and Examination:
Oral opening three fingerbreadths, Mallampati 3-nl. dent.-TMD 3 fingerbreadths-CROM 35° cricoid membrane palpable-
trachea midline.
General Guidelines for Airway Scenario:
1. Lay out the “Equipment Available.”
2. Make sure that hand jet ventilator pressure regulator is turned off. Unless trainees are familiar with the device, they
will think it does not work.
3. Choose Scenario Version IA. When the trainee is ready click on Start Test. Patient will be conscious and ready for
induction.
4. Pulse oximeter will drop from 100% to death over 5 min if an airway is not established correctly (TTJV or
cricothyrotomy).
5. FTLMA, LMA, or Combitube are proper choices but will not work in this scenario (choose low-pressure failure for
them if attempted).
6. The patient will not return to spontaneous ventilation or wake up. The only options that will successfully save the
patient are either cricothyrotomy or TTJV within 5 min of induction.
7. Use the “ASA Difficult Airway Algorithm” performance checklist to guide debriefing of scenario.
8. Use the “ASA Difficult Airway Algorithm” poster as a teaching aide.
9. Review and offer correction of either psychomotor skill sets or knowledge/judgment errors. Let the trainee practice a
skill set till successful.
(Continues)
DESIGN SERVICES OF

Table 13-3 (Continued)
Simulation Instructions for Airway Scenario:
WHEN WHAT HOW

Prior to induction clinically Airway Press “clear all” button
create nl.
Immed. after induction Clinically create cannot intubate or ventilate Press “cannot intubate/ventilate” button
When TTJV or cric. Clinically to make TTJV or cric. work Press “decr. Pulm. Compl.” button
attempted
After 1 min has elapsed Start to decr. SaO2 Press “decr. SaO2” button till ⫽98%
After 2 min have elapsed if Decrease SaO2 further Press “decr. SaO2” button till ⫽90%
airway not established
After 5 min have elapsed if Decrease SaO2 further till hypoxic death Press “decr. SaO2” button till ⫽40%
If airway is established Increase SaO2, allow CO2 detection Press “incr. SaO2” button till ⫽98%, Press
“CO2 on” button
Written by: David Metro, MD for WISER DAM Simulation Course.
F I GUR E 1 3 -1 A view of the actual monitor

screen that the participant sees throughout
the case. All the vital signs are manipulated via
the instructor’s control panel.
DESIGN SERVICES OF

FIG U RE 13- 2 A screen

capture from a computer driving
a Laerdal Simman during an
airway simulation. Note the
undocked ABC window in the
upper left corner. The trainer
only needs to click on the rele-
vant action in this window, and
the script executing the scenario
will automatically configure the
simulator appropriately for that
action. The upper center section
shows a schematic of the simu-
lator indicating its current state.
The screen in the upper right
corner shows the vital signs that
are presented to the trainee.
The lower right corner shows
the long-term trends in hemo-
dynamic data that the script will
execute over the course of the
next few minutes as the sce-
nario plays out.
FIGURE 13-3 The trainer

has clicked on the “Standard
Induction of GA” selection in the
ABC window as indicated by the
single arrow. Note that the simu-
lator has now been automatically
transformed by the scripting
engine into a cannot ventilate,
cannot intubate configuration
(multiple arrows in the upper
center section). Note also that
the hemodynamic trends indicate
a hypoxic arrest will occur in
approximately 5 minutes.
FIG UR E 1 3-4 In the same

scenario, the trainee has chosen
to place a laryngeal mask air-
way, so the trainer clicks on this
selection in the ABC window.
The simulation is configured
to allow the LMA to be placed
(two arrows in the center sec-
tion), but it still will not allow
successful ventilation of the
simulator.
DESIGN SERVICES OF

REFERENCES 10. Russo SG, Eich C, Barwing J, et al. Self-reported changes

in attitude and behavior after attending a simulation-aided
1. American Society of Anesthesiologists Task Force on airway management course. J Clin Anesth. 2007;19(7):
Management of the Difficult Airway. Practice guidelines 517–522.
for management of the difficult airway. Anesthesiology. 11. Quinlan J, Schaefer J. Functional validity of airway tech-
2003;98:1269–1277. niques in whole task human simulation using the Laerdal
2. Peterson GN, Domino KB, Caplan RA, et al. Management of Simman. Anesthesiology. 2005;103:A1156.
the difficult airway: a closed claims analysis. Anesthesiology. 12. Binstadt E, Donner S, Nelson J, et al. Simulator training
2005;103:33–39. improves fiber-optic intubation proficiency among emer-
3. Romeo R, Quinlan J, Metro D, et al. Difficult airway man- gency medicine residents. Acad Emerg Med. 2008;15(11):
agement using human dynamic macrosimulation: practic- 1211–1214.
ing anesthesiologists do not follow the ASA Difficult Airway 13. Davis DP, Buono C, Ford J, et al. The effectiveness of a
Guidelines. Anesthesiology. 2004;101:A1262. novel, algorithm-based difficult airway curriculum for air
4. Romeo R, Quinlan J, Metro D, et al. Difficult airway manage- medical crews using human patient simulators. Prehosp
ment using human dynamic macrosimulation—revisited. Emerg Care. 2007;11(1):72–79.
Anesthesiology. 2005;103:A1157. 14. Talarico J, Quinlan J, Schaefer J, et al. Validation of whole
5. Program Requirements for Graduate Medical Education task human simulation to measure competency in difficult
in Anesthesiology, effective date 7/2007, Sec IV. A. 5. (a) airway management: reproducibility of repeated testing.
(1) (n). p 17. © 2007 Accreditation Council for Graduate Anesthesiology. 2005;103:A1154.
Medical Education (ACGME), 515 N. State Street, Suite 15. Romeo R, Quinlan J, Metro D, et al. Retention of difficult
2000, Chicago, IL 60610. airway management skills by practicing anesthesiologists.
6. Combes X, Le Roux B, Suen P, et al. Unanticipated difficult air- Anesthesiology. 2005;103:A1218.
way in anesthetized patients: prospective validation of a man- 16. Kuduvalli PM, Jervis A, Tighe SQ, et al. Unanticipated
agement algorithm. Anesthesiology. 2004;100(5):1146–1150. difficult airway management in anaesthetised patients: a
7. Schaefer JJ III. Simulators and difficult airway management prospective study of the effect of mannequin training on
skills. Pediatric Anaesthesia. 2004;14(1):28–37. management strategies and skill retention. Anaesthesia.
8. Byrne AJ, Greaves JD. Assessment instruments used dur- 2008;63(4):364–369.
ing anesthetic simulation: review of published studies. Br J 17. American Society of Anesthesiologists. Simulation Education
Anaesth. 2001; 86 (3):445–450. Network. http://www.asahq.org/SIM/FAQforSEN.pdf
9. Metro D, Foraida M, Quinlan J, et al. Whole task human
simulation accurately predicts competent managers of the
difficult airway. Anesthesiology. 2005;103:A1152.
DESIGN SERVICES OF

CHAPTER
Training in Airway Management

Mark Lischner and James Snyder
14 cn
T his chapter simplifies alternatives to airway training

in terms of polar opposites, neither of which exists in
pure form, to provide a framework for understanding the
unpredicted difficulty and to maximize success despite
their limited experience.
Shorter learning curves have been reported by emer-
value of specific concepts and maneuvers. gency medicine (EM) and critical care medicine (CCM)
In experience-based training, skill is acquired primar- training programs that focused on patients at greater risk.
ily through practice with elective surgery patients, initially In programs designed to manage airways of critically ill
with expert supervision, then with support immediately patients, performance after 6 months experience was com-
available for routine cases as skill develops. Because risk is parable to critical care attendings with an anesthesiology
low, multiple laryngoscopies are acceptable and indepen- background,7 and EM resident performance in postgradu-
dence and efficiency can be priorities. Call for assistance is ate years 3 and 4 were comparable to anesthesiology resi-
a sign of failure, independence a sign of personal skill. dents in postgraduate years 2 to 4.8 In a program where total
After basic skills are acquired, practiced use of endotra- experience may be less than 200 cases, EM resident intubation
cheal tube introducers (ETI) in simulated epiglottis-only success rate in a trauma emergency room was 97%.9
cases is now considered fundamental to airway manage- At the University of Pittsburgh Medical Center about
ment. However, low learning trajectories suggest substan- half of the more than 20 physicians who start CCM fel-
tial dependence on experience. For example, anesthesiol- lowship each year are airway novices. Dispersion of re-
ogy residents required three or more attempts to intubate sponsibility throughout the hospital requires novices
in 14.5% of emergency cases in their first clinical year, with minimal training opportunity unavoidably to serve
10.4% in their second year, and 9% in their third, com- as first responders at emergent events. Despite excellent
pared with 6.3% by attending staff (Fig. 14-1).1 support by operating room (OR) anesthesiology attend-
In contrast to experience-based training, careful ing staff, program requirements entail clinical responsibil-
preparation for “first pass success” has been emphasized ity before training described above for EM programs can
by Levitan and others to address different clinical and be provided. Although CCM attendings are in-house and
training program needs.4–6 The focus is on optimal care attend codes 24/7, proximity and multiple simultaneous
of critically ill patients and achieving highest possible suc- events result in potential for unsupervised novices being
cess rate with least patient risk. Ideally, the end-product the first responders to codes. Advance training using ca-
is a smoothly coordinated sequence of maneuvers that davers has been restructured to assertively apply advanced
achieves optimal glottic exposure and enables even nov- airway skills, including first pass success as championed
ices first pass success despite unpredicted difficulty. The by Levitan.4–6 Novice CCM fellows self-reported success in
educational structure that leads to firstpass success is re- 85% (78% first pass) of their first 99 intubations of criti-
lated to reverse engineering to understand individual skills cally ill patients in 2007 (10 fellows, mean 7.6, range 1
and provision of support during intubation that allows ex- to 13).10 Data collection was not quality-controlled well
ploration and practice of each skill independently, then in this pilot study; subsequent quality-controlled data are
in combination with other skills. Every case is presumed now being analyzed.
an unpredicted difficult intubation, justifying planned Factors that favor accelerated training in airway care and
incorporation of passersby as assistants and emphasis on techniques that appear to accelerate the success rate and/or
navigational tools to ensure the objective, and application patient safety are summarized in Tables 14-1 and 14-2.
of every support until exposure is optimal rather than ad- Although there is need for increased and accelerated
equate. Skills are acquired via “dry lab” simulation and training and the number of cases is declining, several
cadaver training when available. In every case, trainees are factors may weigh against incorporation of the first pass
encouraged to prepare for advanced techniques in case of approach to direct laryngoscopy (DL) (Table 14-2).
103

F I GUR E 1 4 -1 Intubation: conventional Learning Curve Intubation

learning curves for intubation by DL. The 1.0
solid and dashed-line curves indicate self-
reported success rate for anesthesiology
Probability of Good Intubation

trainees during OR training in two centers.2,3 0.8
Solid: Konrad et al.2 Dashed: Mulcaster
et al.3 Low X: Novice paramedic trainee suc-
0.6
cess rate in OR after conventional
orientation. High X: Novice paramedic
trainee success rate after similar training plus 0.4
advance viewing of operator-view videos.4
Circle: Novice CCM fellows after advance
video of operator view and cadaver lab.5 0.2
0.0
0 10 20 30 40 50 60 70 80 90
Number of Intubations
Table 14-1
Factors that Favor Accelerated Training in BMV and DL
Fewer cases:
• Fewer intubations due to increased use of supralaryngeal devices.
• Emphasis on rapid postoperative recovery.
• Increasing availability of sophisticated alternatives to DL and interest to test or acquire skill with them leave fewer
predictably difficult cases to learn advanced DL techniques.
• Concern for patients’ rights and need for informed consent.
Increased need and increased acuity:
• Diffusion of demand to nonanesthesiology-based training: Training programs for EM, CCM, pulmonary medicine,
hospitalist practice, and emergency medical technicians are preparing trainees for airway management, often in
patients better-served by an advanced than beginner approach due to nonfasting and physiologically unstable
status.7–10 Typically, these trainees are provided airway experience in the OR, but the number is limited and usually
difficult cases selected out.
• Increase in patient acuity: Spread of intensive care facilities throughout large hospital complexes and increased acuity of
hospitalized patients increase the likelihood of emergent events distant from the OR.
• Decrease in availability of expert anesthesiologists: Increase in clinical intensity has reduced the ability of
anesthesiologists to respond to codes outside the OR.
• Advanced training in and preparation for techniques shown effective in difficult cases may improve performance
in predicted and unpredicted difficult scheduled OR cases.
Table 14-2
Factors that Weigh against Acquisition of New DL Techniques
• Low failure rate in the OR and routine ability to sustain gas exchange without perceived morbidity may diminish
motivation to improve.
• Exploration of new methods not required for the case at hand is opposed by concern with short-term efficiency.
• The objective to maximize glottic exposure inherently opposes conventional ideologies of independent function
and successful intubation with least glottic exposure.
• Techniques found helpful may be considered alternatives rather than means to a higher success rate.
• Some techniques seem contrary to conventional teaching and clinical impression—especially maximal flexion
and thoracic flexion.

CHAPTER 14 ■ TRAINING IN AIRWAY MANAGEMENT 105
Table 14-2
Factors that Weigh against Acquisition of New DL Techniques
• Measurement tools assess the effect of specific techniques in an individual case and across cases are not in common
use. For example, POGO is more useful than Cormack-Lehane (CL) grades 1-2, and detailed descriptions of
epiglottis exposure are more useful than CL grade 3. Also, frequent assessment of effective compliance (isolation of
force required to displace the tongue from the force required to lift the head) informs the effect of maneuvers, for
example, the effect of head elevation to achieve a given POGO.
• Acceptance of the monocular field as a fixed limitation may contribute to underutilization of tools that enable
shared internal view. (For contrast, see Advance review, Blade-based view).
• The infrequency of difficult intubations for experienced practitioners in the OR converts the inherent common
skill indicator from a clinical outcome (success rate) to a technical ability (to intubate with least glottic exposure).
Frequency of two or more attempts, or statement of best POGO obtained, would be more relevant to skill with
difficult or emergent cases.
• Lack of structure to assure achievement of complete skill set: The acquisition of each skill could inhibit additional
skill acquisition unless training ensures development of each. For example, novices who experience the value of
ELM may be less likely to become facile with independent elevation and manipulation of the head and neck, and
vice versa, or, to integrate both techniques.
• Lack of orientation to simulate situations that require specific skill sets. Techniques to address difficult DL are
more likely to be considered “tricks” than required skills, and skills in BMV are simply presumed to require
months of OR experience (ref).
Abbreviation: ELM, external laryngeal manipulation; POGO, percent of glottic opening.
SPECIFIC TRAINING PROGRAM by comparison of X-rays, palpation, and direct observa-

tion (See Anatomy Chapter 1) is helpful. However, expe-
CONCEPTS AND TECHNIQUES riential exercises convey the reality of flexion-facilitation
Just as skilled practitioners continue to simulate epiglot- most effectively.
tis-only exposure in preparation for unpredicted difficult Reproducing Levitan’s demonstration is helpful4.
cases,11,12 there are multiple techniques that novices can After a curved or straight blade is positioned to optimally
routinely employ to improve reliability of glottic exposure expose the glottis, routinely the percent of glottic open-
(Table 14-3). Those same techniques are applicable when ing (POGO) can be directly observed to increase from less
well-experienced practitioners encounter unexpected dif- than 50%to near 100% as the head is lifted from flat on
ficulty, or patient circumstances make first pass success the table, and POGO does not decrease as head elevation
especially desirable. This focus both on patients at risk is continued to maximal. In fresh unpreserved cadavers,
and operators with minimal experience encourages sepa- the POGO continues to improve or remains high as rota-
rate practice of each potentially valuable skill, and then tion forward is continued until the vector on the handle
practice in integrated application of those skills. The end- is toward the feet. In this position, the trachea is vertical,
product should be a smooth integration of techniques and as is the ET during insertion. A blade-based optical sys-
advanced maneuvers that facilitates rapid exposure with tem (C-Mac, KARL STORZ Gmbh &Co. KG or Glidescope
minimal force and optimal controlling less than 20 sec- Direct Intubation Trainer, Verathon Inc., Bothell, WA—
onds, until exposure is optimal, then precise atraumatic see Chapter 24) can be useful to assure stable positioning
ET placement. of the blade relative to the glottis during this head move-
ment exercise.
Two clinical impressions that weigh against flexion
should be considered. First, in some cases it is apparent
CREDULITY OF FLEXION-FACILITATION that thoracic spine flexion should precede cervical spine
OF DL flexion. For example, in obese patients and in many with
a short or thick neck, cervical flexion rotates the chin
Although practical studies consistently support maximal
and anterior neck toward the upper chest and impairs
head elevation to facilitate glottic exposure, conventional
DL by decreasing submandibular effective compliance.
concepts and clinical impressions that favor extension may
Impingement of tissue is avoided when thoracic flexion
cause cognitive dissonance. Visualizing flexion-facilitation

Table 14-3
Concepts (Re)Discovered to Improve DL Success in Difficult Cases, and Techniques and Comments
Advance Learning of the Operator View

Study of the authentic operator view doubled novices’ initial success rate13 (Fig. 14-1).
Shared Viewing
A blade-based view transmitted to a bedside or device-based screen enables the trainee and the instructor access to the
effects of the other’s manipulations. Alternating between blade-based and direct viewing is useful to convey the value
of ELM in stabilizing the tongue during blade insertion.
Communicating the “epi flip” is far easier when viewed by instructor and trainee. Comparison of the blade view of blade
tip position relative to the hyoepi glottic ligament and the corresponding DL view of the epiglottis response to “pulsed”
tip pressure is highly instructive of how to position the blade in DL.
Instructor confirmation via blade-based view of the trainee controlling the epiglottis before attempting glottic exposure is
important to avoid bypass of the epiglottis, as is tempting in easy cases.
The blade-based view also facilitates an assistant’s fine-tuning glottic exposure by his/her external laryngeal manipulation.
Rapid Acquisition of Optimal Glottic Exposure
Because the most difficult cases may require maximal (thoracic as well as cervical) flexion, advance considerations
inlcude lower table, shoulder roll or ramp construction, and voice control of assistants to enable routine use of external
laryngeal manipulation (ELM).
Routine Use of ELM
Employment of ELM early in training may help convert the trainee’s approach to laryngoscopy from “probing with a
stick” to a more dynamic exploration.
Glottic Exposure Optimal Rather than Adequate
Axial manipulation is routinely employed simultaneously with ELM until further improvement in glottic exposure cannot
be made.
Precise Control of Delicate Tissue
Fine left-hand motor control is enabled when lifting force is assumed by the assistant’s or the operator’s right hand.
Bimanual manipulation converts probe with a stick to multilateral exploration.
The “epi flip” defines optimal position of curved blade tip.
Maintain Orientation
The priority is to find and control, not circumvent, the epiglottis.
Bimanual manipulation can facilitate tongue control and early sighting and tracking of the epiglottis.
Evaluate Effect of Manipulations
The value of ongoing axial and ELM manipulations is informed by tracking effective compliance of the submandibular
space: by frequent gentle blade lift to assess how much of the epiglottis or glottis (percent of glottic opening, or POGO)
can be seen.
Incorporate Simulation of Difficult Cases into Routine Practice
Practice shifting the angle of approach toward the right corner of the mouth with the curved as well as the straight blade
to become familiar with blade-dentition interaction as well as altered view of landmarks.
Isolated Skill Practice
Isolation of skill practice fosters more complete development. For example, rapid initial axial positioning with support
provided by an assistant removes force required to lift the head from that required to displace the tongue. Then precise
techniques such as the epi flip and ELM can be explored with a light touch.
Smooth Integration of Multiple Techniques
Facility with basic techniques makes most intubations straightforward. That the next case may be the most difficult ever
encountered encourages continued application and integration of every technique.
Team Practice/Advance Instruction of Assistants
Inevitability of unpredicted crisis combined with the need to call on naïve passersby requires that concise clear
instruction be worked out and practiced in advance.

CHAPTER 14 ■ TRAINING IN AIRWAY MANAGEMENT 107
displaces the head forward relative to the chest (Figs. 5-2, which is required to deliver manual continuous positive
5-3, 5-4 and 5-6). On this basis, thoracic spine flexion may airway pressure (CPAP). “Bagging by feel” applying CPAP
be an important benefit from building a ramp for airway via bedside resuscitation bags is taught routinely at the
care of morbidly obese patients. Other observations valu- University of Pittsburgh CCM Training Program.
ing thoracic spine flexion are summarized in Chapter 1. Trainee ability to sense and synchronize assistance by
A second clinical impression that opposes flexion is feel allows their visual attention elsewhere during a code.
how inability to lift the tongue in difficult DL is inter- Within two breaths of a decrease in compliance they should
preted. Often the mechanism is perceived “an anterior be able to differentiate the cause as inspiratory obstruction,
larynx,” and the idea of flexion seems like lifting your a soft palate flap valve, air trapping, or reduced thoracic
head when you can’t see under something. This bias wall compliance. Most manikins constructed to teach re-
seems to derive from the three axes alignment theory, suscitation have substantial pharyngeal leaks that prevent
which orients to aligning the posterior airway structures, sensing an effective mask seal, which is the fundamental
and so opposes flexion. We suggest impairment of soft requirement to learning to bag by feel. Therefore, fellows
tissue displacement forward is due primarily to tension acquire bag-sense skills and are tested in a jury-rigged sys-
in the SHL suspension cable, which is relieved by flexion tem where spontaneous breathing is simulated by pulling
in the low cervical and thoracic spine, and impingement open a QuickLung (by IngMarMedical) or Standard (TTL
of anterior tissue spaces, which spaces are separated by bellows). Then bag-sense is tested in spontaneously breath-
thoracic flexion (Fig. 5-4). ing cadavers as below. (We have not yet made this teaching
We are aware of only two observations of axial ma- structure exportable, so many practitioners are unaware of
nipulation in difficult DL that did not conclude in favor such skills and still believe “anyone can bag.”)
of flexion. First, Chevalier Jackson14,15 recommended
extension just a few years after DL in humans was first Airway and Mask Technique
described; later he fully reversed his recommendation, As in DL, early concentration on advanced mask and
emphasizing that if the head was held high enough, even airway techniques has been helpful for trainees who en-
a-o extension could be unnecessary. Second, a single counter difficult airways early in the course of their fel-
center MRI study concluded that axis alignment with lowship. Concern about occult hypoxia in code situations
moderate flexion (7 cm head elevation) was not different sets our bias to apply a two-hand jaw thrust to open the
from head flat on the table.16 The images appear to show airway when applying the mask, and low-pressure assisted
cervical spine curvatures different from those we would ventilation with BIPAP. The trainee may back off to less
consider typical for these positions. aggressive techniques as continued airway patency and
effective mask seal justifies. Training in advanced mask
and airway techniques requires realistic anatomic and tis-
BAG-MASK-VENTILATION sue character variations (prominent nose, hollow cheeks,
flaccid tongue, flap valve soft palate, subluxing jaw)
By conventional training, effective bag and mask skills re- that have not yet been simulated from tissue surrogates.
quire months of OR experience. The Critical Care Medicine Advanced airway training is provided by simulating spon-
Multidisciplinary Training Program at the University of taneous ventilation in unpreserved cadavers, by transmis-
Pittsburgh provides airway-novice fellows a foundation of sion of bellows-generated negative pressure via endobron-
bag-mask-ventilation (BMV) skills within a few lab ses- chial tubes inserted retrograde via thoracotomy.
sions over several days.
“Feel of the Bag”

The anesthesiologist with a hand on the soft latex bag in
REFERENCES
a low-resistance breathing system learns to become quite 1. Mort TC. Emergency tracheal intubation: complications
sensitive to subtle changes in pattern such as due to pa- associated with repeated laryngoscopic attempts. Anesth
tient effort, airway trapping, and upper airway obstruction. Analg. 2004;99:607–613.
During open thoracotomy in the OR (or in non-preserved 2. Konrad C, Schüpfer G, Wietlisbach M, et al. Learning
cadavers laboratory), direct observation of hand pressure manual skills in anesthesiology: is there a recommended
recruitment of sub pleural and segmental atelectasis is also number of cases for anesthetic procedures? Anesth Analg.
1998;86(3):635–639.
highly informative.
3. Mulcaster JT, Mills J, Hung OR, et al. Laryngoscope intu-
Because self-inflating resuscitation bags in the bation: learning and performance. Anesthesiology. 2003;98:
Baltimore Shock-Trauma ICU provided less sensitivity, Dr. 23–27.
Crawford McAslan used inflated latex bags from the OR to 4. Levitan RM, Goldman TS, Bryan DA, etal. Training with
recruit atelectasis in ICU patients (JVS, personal commu- video imaging improves the initial intubation success rates
nication). Subsequently it was observed that sensory feed- of paramedic trainees in an operating room setting. Ann
back from a self-inflating bag was enhanced by in-flexing, Emerg Med. 2001;37(1):46–50.

5. Agrawal R, Orebaugh SL, Chelluri L, et al. Initial intubation 13. “http://www.ncbi.nlm.nih.gov/pubmed?term=%22Ochroch

performance by minimally experienced trainees after multi- %20EA%22%5BAuthor%5D” Ochroch EA, “http://www.ncbi.
faceted training using evidence based maneuvers. Crit Care nlm.nih.gov/pubmed?term=%22Hollander%20JE%22%5B
Med (Abstract Issue). 2007;35:462,p.A126. Author%5D” Hollander JE, “http://www.ncbi.nlm.nih.gov/
6. Levitan RM, Chudnofsky C, Sapre N. Emergency airway pubmed?term=%22Kush%20S%22%5BAuthor%5D” Kush S,
management in a morbidly obese, noncooperative, rap- “http://www.ncbi.nlm.nih.gov/pubmed?term=%22Shofer%20
idly deteriorating patient. Am J Emerg Med. 2006;24(7): FS%22%5BAuthor%5D” Shofer FS, “http://www.ncbi.nlm.
894–896. nih.gov/pubmed?term=%22Levitan%20RM%22%5BAuthor
7. Levitan R. The importance of a laryngoscopy strategy and %5D” Levitan RM. Assessment of laryngeal view: per-
optimal conditions in emergency intubation. Anesth Analg. centage of glottic opening score vs Cormack and Lehane
2005;100(3):899–900. grading. “javascript:AL_get(this,%20‘jour’,%20‘Can%20J%20
8. Levitan RM. Patient safety in emergency airway manage- Anaesth.’);” Can J Anaesth. 1999;46:987-90.
ment and rapid sequence intubation: metaphorical lessons 14. Murphy MF, Hung OR, Law JA. Tracheal intubation: tricks
from skydiving. Ann Emerg Med. 2003;42(1):81–87. of the trade. Emerg Med Clin N Am. 2008;26:1001–1014.
9. Schwartz DE, Matthay MA, Cohen NH. Death and other 15. Levitan RM, Mickler T, Hollinder JE. Bimanual laryngos-
complications of emergency airway management in criti- copy: A Videographic Study of External Laryngeal manipula-
cally ill adults: a prospective investigation of 297 tracheal tion by Novice Intubators. Ann Emerg Med 2002;40:30-37.
intubations. Anesthesiology. 1995;82:367–376. 16. Levitan RM, Mechem CC, Ochroch EA et al. Head-Elevated
10. Levitan RM, Rosenblatt B, Meiner EM, et al. Alternating day Laryngoscopy Position: Improving Laryngeal Exposure
emergency medicine and anesthesia resident responsibil- During Laryngoscopy by Increasing Head Elevation. Ann
ity for management of the trauma airway: a study of laryn- EM 2003;41:322-330.
goscopy performance and intubation success. Ann Emerg 17. Jackson C. Peroral Endoscopy and Laryngeal Surgery.
Med. 2004;43:48–53. St. Louis, MO: The Laryngoscope Company; 1915.
11. Sakles JC, Laurin EG, Rantapaa AA, et al. Airway manage- 18. Jackson C, Jackson CL. Bronchoscopy Esophagoscopy and
ment in the emergency department: a one-year study of Gastroscopy: A Manual of Peroral Endoscopy and Laryngeal
610 tracheal intubations. Ann Emerg Med. 1998;31(3): Surgery. 3rded. Philadelphia, PA: WBSaunders Co.; 1934.
325–332. 19. Adnet F, Borron SW, Lapostle F, et al. Study of the “sniffing
12. Cormack RS, Lehane J. Difficult tracheal intubation in position” by magnetic resonance imaging. Anesthesiology.
obstetrics. Anaesthesia. 1984;39:1105–1111. 1996;85:787–793.

CHAPTER
Examples and Illustrations

of Conditions Predisposing to
15 cn
Difficult Airway Management

Samer Melhem and Mario Montoya
ANATOMIC ABNORMALITIES Nasal Turbinates

Prominent or protuberant nasal turbinates may create an
Limited Mouth Opening
obstruction to passage of nasopharyngeal airways or nasal
Limitations in mouth opening impede the ability of the ETTs leading to trauma and epistaxis, which can be se-
laryngoscopist to visualize pharyngeal or laryngeal struc- vere, especially if the patient is in an anticoagulated state
tures. Ideally, mouth opening should exceed 6 cm or (Fig. 15-8).
3 fingerbreadths (Fig. 15-1).
Facial Hair
Disproportionally Large Tongue
Bushy beards or goatees may complicate attempts to make
Direct laryngoscopy requires that the tongue be forced into
a face mask seal, resulting in difficult mask ventilation
the floor of the mouth to permit the laryngoscopist to view
(Fig. 15-9).
the glottis. The larger the tongue, the more difficult this
becomes, contributing to poor laryngoscopy grades. The
disproportionally large tongue is usually evident when the
Mallampati class is evaluated (Fig. 15-2).
CONGENITAL ANOMALIES
Dental Abnormalities
Many congenital anomalies affecting facial, oral, pharyn-
Large, protruding teeth, or teeth lying at odd angles may geal, or cervical structures create challenging intubating
complicate attempts to place the laryngoscope in the conditions.
mouth, visualize the laryngeal orifice, or place an endo-
tracheal tube (ETT). They may also be at higher risk for Oral Cavity
tooth damage during direct laryngoscopy, as well as ETT
Some congenital abnormalities result in enlargement of
cuff damage during intubation (Figs. 15-3 and 15-4).
the tongue (macroglossia). This is commonly seen in
Abnormal Neck Size or Mobility Down syndrome, Beckwith-Wiedmann syndrome, as well
as other chromosomal abnormalities. Macroglossia can
Patients with short, thick necks may present difficulty in
also be seen with mucopolysaccharidosis, hypothyroid-
achieving normal extension and frequently have worse
ism, alpha-mannosidosis and aspartylglucosaminidase
laryngoscopy grades at direct laryngoscopy than patients
deficiency (Fig. 15-10).
with long, thin necks. Positioning in these patients can
greatly improve laryngoscopy success (Fig. 15-5).
Larynx
Mandibular Size Airway stenosis may be a congenital condition, or may be
A small mandible, or receding chin, adversely affects the associated with prolonged intubation, making passing an
ability to visualize the glottis making the grade of laryn- ETT difficult (Fig. 15-11).
goscopy worse (Fig. 15-6).
Cervical Spine
Epiglottis Cervical spine skeletal anomalies may complicate attempts
Occasionally, the elongated epiglottis is difficult to elevate to manage the airway by conventional means, due to ei-
sufficiently with the curved blade, and a straight blade ther decreased range of motion (making axis alignment
must be used to lift it directly out of the way (Fig. 15-7). difficult), or to ligamentous instability (Fig. 15-12).
109

F IG U R E 1 5 -1 Limited mouth opening.
F IG U R E 1 5 -2 A disproportionally large
tongue.
(From Benjamin B, Bingham B, Hawke M,
et al. A Color Atlas of Otorhinolaryngology.
Philadelphia, PA: JB. Lippincott Co; 1995, with
permission.).
F I GU R E 1 5 -3 Large, protuberant incisor teeth.

CHAPTER 15 ■ EXAMPLES AND ILLUSTRATIONS OF CONDITIONS PREDISPOSING 111
FIG U RE 15-4 Severe dental malocclusion.

permission.)
FIG U RE 15-5 Short thick neck: a grade

3 laryngoscopy was present in this patient.
FIG U RE 15-6 Short mandible with

overbite.

F I G U R E 1 5 -7 Long, floppy epiglottis.
F IG U R E 1 5 -8 Prominent nasal turbinate.

permission.)
F I GUR E 1 5 -9 This beard resulted in poor

mask ventilation.

FIG U RE 15-11 Congenital subglottic stenosis.

(From Benjamin B, Bingham B, Hawke M, et al. A Color Atlas
of Otorhinolaryngology. Philadelphia, PA: JB. Lippincott Co;
1995, with permission.)
F I GUR E 1 5 -1 0 Enlarged tongue in Down syndrome.

FIG U RE 15-12 Severe cervical spine anomaly

in Klippel-Feil syndrome.
(Courtesy of Dr. Barton Branstetter, Department
of Radiology, University of Pittsburgh Medical
Center.)

F I GUR E 1 5 -1 3 Congenital facial

malformation evident on 3-D CT scan.
Center.)
Facial Skeleton
Abnormalities of the maxilla or mandible can complicate
face mask ventilation and direct laryngoscopy in diseases
such as Pierre Robin syndrome, where the mandible is ab-
normally small (micrognathia) (Fig. 15-13).
Neck
Large congenital malformations may compromise the air-
way, necessitating tracheostomy (Fig. 15-14).
PATHOLOGY
Many diseases of the head, neck, and chest can adversely
affect direct laryngoscopy.
F I GUR E 1 5 -1 4 Congenital subglottic hemangioma which INFECTION

mandated tracheostomy in this infant.
Epiglottitis
of Otorhinolaryngology. Philadelphia, PA: JB. Lippincott Co; Infection of the epiglottis and supraglottic region can cre-
1995, with permission.) ate life-threatening airway obstruction.

In epiglottitis, often caused by Haemophilus influenzae Nasopharyngeal Carcinoma

type b in children, severe supraglottic edema and erythema Like other airway tumors, nasopharyngeal carcinoma may
may lead to airway obstruction. This mandates securing become extensive before discovery. In the MRI shown in
of the airway by endotracheal intubation via direct laryn- Fig. 15-22, widespread involvement of the nasopharynx
goscopy or by surgical means if necessary (Fig. 15-15A). is evident.
A lateral soft tissue cervical radiograph usually reveals
the “thumb sign” of an enlarged, inflamed epiglottis
(Fig. 15-15B). TRAUMA
Ludwig Angina Mandibular Fracture
Infection of the floor of the mouth, usually an extension Mandibular fracture usually results in trismus, edema, and
of dental infection (“trench mouth”), can cause severe distortion of intra-oral structures. This may make direct
pain on swallowing, trismus, and difficulty opening the laryngoscopy and intubation by the oral route difficult.
mouth and displacing the tongue during direct laryngos- Figure 15-23A shows a CT scan of a severe, comminuted
copy. Figure 15-16A shows a patient with swelling and mandibular fracture. The supporting ring of the mandible
erythema of the submandibular space, a manifestation of is lost, resulting in a “flail mandible.” Figure 15-23B de-
Ludwig angina. Figure 15-16B shows a CT of a patient picts the surgical repair of the comminuted fracture shown
with Ludwig angina. Note the extent of swelling and in Fig. 15-23A.
potential airway compromise.
Facial Fractures
Retropharyngeal Abscess Bleeding, edema, loss of anatomic landmarks, and airway
This process, most common in young children, causes obstruction combine to make management of the airway
neck stiffness and bulging of the posterior pharyngeal very challenging in these patients. If the airway is inac-
wall. In Fig. 15-17, a CT of a patient with retropharyngeal cessible or unrecognizable, surgical airway is necessary
abscess shows marked prevertebral edema and narrowing (Fig. 15-24).
of the upper airway.
Cervical Spine Fracture/Dislocation
Dental Abscess Recognized or potential cervical spine injury mandates
Large abscesses may lead to trismus and distortion of in- extreme care with airway management. Cervical spine
tra-oral structures. Figure 15-18 shows a patient with a flexion or extension may result in spinal cord injury. In-
dental abscess and significant jaw swelling and is likely to line cervical immobilization is typically used in the trauma
have trismus. patient with potential spine injury who requires intuba-
tion for airway control. Patients with known cervical spine
Peritonsillar Abscess injury are managed with fiberoptic flexible or rigid optical
scopes, or other forms of intubation that require no sig-
An abscess in the tonsillar fossa often results in drooling,
nificant motion of the cervical spine (Fig. 15-25).
trismus, odynophagia, and bulging of the soft palate of the
affected side. Figure 15-19 depicts a peritonsillar abscess Laryngeal Injury
with bulging soft palate and copious exudate.
Blunt injury to the larynx may result in fractures of the
cartilages or disruption of the airway. Airway management
attempts with direct laryngoscopy may fail or worsen the
NEOPLASMS injury. Figure 15-26 shows a laryngeal fracture. Disruption
of the laryngeal cartilages is evident in this CT of the lar-
Supraglottic Cancer ynx. Tracheostomy may be necessary in such patients, un-
Carcinoma of the pre-epiglottic space, shown in til surgical repair can be undertaken.
Fig. 15-20, makes direct laryngoscopy difficult, particu-
larly with a curved blade.
EDEMA
Laryngeal Carcinoma Edema of the oral cavity, neck, larynx, or pharynx from
Carcinomas of the larynx may be relatively silent until various causes may compromise the airway and compli-
they have progressed to significant airway obstruction cate attempts at face mask ventilation and direct laryngos-
(Fig. 15-21). copy (Figs. 15-27–15-29).

F I GU R E 15 - 15 A: Severe supraglottic edema and erythema in acute epiglottitis. (From Benjamin B, Bingham B, Hawke M,
et al. A Color Atlas of Otorhinolaryngology. Philadelphia, PA: JB. Lippincott Co; 1995, with permission.) B: Enlarged,
“thumb-shaped” epiglottis evident on lateral soft-tissue cervical radiograph.
(Courtesy of Dr. Barton Branstetter, Department of Radiology, University of Pittsburgh Medical Center.)

F I GU R E 15 - 16 A: Swelling and erythema of the submandibular space. (From Benjamin B, Bingham B, Hawke M, et al. A Color
Atlas of Otorhinolaryngology. Philadelphia, PA: JB. Lippincott Co; 1995, with permission.) B: CT of a patient with Ludwig angina.
(Courtesy of Dr. Barton Branstetter, Department of Radiology, University of Pittsburgh Medical Center.)

F I GUR E 1 5 -1 7 Retropharyngeal abscess.

(Courtesy of Dr. Barton Branstetter, Department of
Radiology, University of Pittsburgh Medical Center.)
ARTHRITIS/BONY HYPERTROPHY MISCELLANEOUS

Arthritic changes of the temporomandibular joints, the Hematoma, tissue infiltration, or hypertrophy of tissues in-
atlanto-occipital joint, or the joints of the cervical spine volving the airway may distort structures, restrict range of
can make direct laryngoscopy very challenging and may motion, or reduce the space available for viewing or place-
mandate awake intubation, depending on the degree of in- ment of airway management tools (Figs. 15-32–15-34).
stability or restriction of motion (Figs. 15-30 and 15-31).

FIG U RE 15-18 Dental abscess with significant jaw swelling.

(From Benjamin B, Bingham B, Hawke M, et al. A Color Atlas of
Otorhinolaryngology. Philadelphia, PA: JB. Lippincott Co; 1995, with
permission.)
FIG U RE 15-19 Peritonsillar abscess.
FIG U RE 15-20 Carcinoma of the pre-epiglottic

space.
(From Benjamin B, Bingham B, Hawke M, et al. A Color
Atlas of Otorhinolaryngology. Philadelphia, PA: JB.
Lippincott Co; 1995, with permission.)

F I GUR E 1 5 -2 1 Laryngeal carcinoma.

of Otorhinolaryngology. Philadelphia, PA; JB. Lippincott Co;
F I GUR E 1 5 -2 2 Nasopharyngeal carcinoma.

Center.)

FIG U RE 15-23 A: Severely comminuted

mandibular fracture. B: Surgical repair
of fracture pictured in Figure 15-23A.
(Courtesy of Lison Yeung, DDS and Dr. William
Chung, Department of Oromaxillofacial
Surgery, University of Pittsburgh School of
Medicine.)

F I GUR E 1 5 -2 4 A LeFort I fracture of the

midface. Multiple nasal fractures and maxillary
sinuses filled with blood are evident on this
coronal CT scan.
Center.)
F I GUR E 1 5 -2 5 This tomogram shows

marked anterior displacement of C6 on C7 due
to bilateral facet dislocation.
Center.)

FIG U RE 15-26 Laryngeal fracture.

permission.)
FIG U RE 15-27 Postoperative neck edema

from shoulder arthroscopy. This can become
severe enough to shift the trachea and occlude
the airway.

F IG U R E 1 5 -2 8 Generalized edema of the

oral cavity, pharynx, and airway from radiation
is evident in this CT scan.
Center.)
F IG U R E 1 5 -2 9 Viral laryngotracheobronchi-
tis frequently causes significant upper airway
edema, resulting in inspiratory stridor.
permission.)
F I GU R E 1 5 -3 0 CT scan reveals osteoarthritis

of the cervical spine with large osteophyte at
C2, protruding into the posterior pharynx.
Center.)

FIG U RE 15-31 This CT shows severe

changes of rheumatoid arthritis in the cervical
spine at C1-C2. This patient would have
significant atlanto-occipital instability.
Center.)
FIG U RE 15-32 Hematoma of the carotid

sheath from a pseudoaneurysm is evident in
this CT scan, resulting in localized tissue distor-
tion and compromise of the upper airway.
Center.)

FIG U RE 15-34 Enlargement of the tongue in amyloidosis.

F I GUR E 1 5 -3 3 Markedly enlarged thyroid gland.
(From Benjamin B, Bingham B, Hawke M, et al. A Color Atlas 1995, with permission.)

PART
Adjuncts to Direct Laryngoscopy
III
CHAPTER
Mirror Blades and Prism Blades 16 cn
Matthew J.P. LoDico and Raymond M. Planinsic
Concept attachment to the standard MacIntosh blade, and provided

a generous 30° of light refraction (Figs. 16-2 and 16-3).3
A subsequent evolution of the prism blade is the Belscope.
When the glottis is difficult to visualize via traditional
This is a derivation of the straight blade, with a 45° angula-
direct laryngoscopy (DL), indirect line-of-sight devices
tion at its midpoint as well as a design that incorporates an
have been used to facilitate endotracheal tube (ETT)
optional prism, and is available in three sizes.4 Although
placement. Two physical objects that can change the angle
these devices may improve a grade 3 or grade 4 view of the
of reflected light are the mirror and the prism. These have
larynx, they may also reduce the room needed for manipu-
been incorporated into laryngoscopic blades with varying
lation of the ETT in the mouth.
success. The mirror blades enable a more “anterior” view
One of the limitations of using either prism or mirror
of the larynx by reflecting the light. However, this reflec-
blades is the potential for fogging. This challenge can be over-
tion comes with the price of an inverted image, which
come by warming the devices before use, or the addition of a
can make initial use awkward. Two examples of blades
defogging solution. However, this preparatory work cannot be
that incorporate mirrors are the Siker blade1 (Fig. 16-1)
managed easily outside of the operating room (OR). In these
and the Neustein blade. The Neustein involves a mirrored
settings, the Airtraq, another prism-based device, can be of
attachment to the MacIntosh (Mac) blade that includes a
great use. The Airtraq is essentially a self-contained single-use
guide channel for a stylet, over which the ETT is passed
airway device with mirrors and a prism at its heart (Figs. 16-4
following blade removal.2
and 16-5). The device is constructed of plastic and is therefore
The prism can also be harnessed to obtain a better
more resistant to fogging. For routine OR use, inclusion of
laryngoscopic view, and its utility has been understood
an antifog solution is advisable; however, the device is func-
since the early 20th century. It was not until the 1960s
tional in an emergency without such accessories. It also has
when Huffman described a prism made from Plexiglas that
the advantage of being one integrated tool, and therefore it is
the concept came to fruition and became practical for use
impossible to misplace or scratch the integral prism, which is
in airway management. Huffman’s prism was designed for
all too easy to do with the small Huffman devices. The Airtraq
FIG U RE 16-1 The Siker blade.
127

128 PART III ■ ADJUNCTS TO DIRECT LARYNGOSCOPY
F I G U R E 1 6 -2 Prism for 3 Mac blade.
F I G U R E 1 6 -3 Prism for 3 Mac blade,

mounted.
F IG U R E 1 6 -4 The Airtraq device.
DESIGN SERVICES OF

CHAPTER 16 ■ MIRROR BLADES AND PRISM BLADES 129
FIG U RE 16-5 Internal view of Airtraq device.

Note prism and mirrors, as well as multiple
lenses.
comes in several sizes, designed for oral, nasal, and double known or encountered difficulty with DL, the blade was
lumen endobronchial intubation. Indications for use include effective.4 Only rarely was the prism used.
airway management in patients who are at risk for difficult The Airtraq has been evaluated in a number of mostly
intubation,5 morbidly obese,6 and/or in cervical spine immo- small, (n ⫽ 40 to 100) randomized studies comparing
bilization.7 The Airtraq would therefore be uniquely suited the effectiveness of the device head to head with DL or
to be included among equipment on ambulances and in dif- other adjuncts for a given indication.5–7 One of these
ficult airway bags. In these situations, in which space is quite studies included patients with expected difficult airways
limited, inclusion of more technically advanced and signifi- and who were intubated with either a MacIntosh blade
cantly more expensive adjuncts (such as a rigid optical stylet or the Airtraq device. The authors found that the Airtraq
or fiberoptic bronchoscope) is seldom practical. The Airtraq was both faster (mean time (SD); 13.4 (6.3) vs 47.7 (8.5)
also has an optional wireless display screen with a reusable s), and had fewer failures. There were four failures in the
camera that can be attached. This screen view increases both MacIntosh group of 20, which were eventually intubated
field of view and discrimination of objects and can be useful with the Airtraq.5 In another comparison of intubation
when training airway novices. with the MacIntosh blade vs the Airtraq, in morbidly obese
patients, a similarly significant shorter time to intubation
with the Airtraq was evident, as well as the need to use it to
Evidence rescue several failed intubations in the MacIntosh group.
In addition, the Airtraq reduced the fraction of patients
The evidence for the use of mirror blades is anecdotal, who developed reduced oxygen saturation (SpO2 ⬍ 92)
rather than comparative. Siker, in his original description during intubation.6 Finally, a different study that evalu-
of the blade, described 99% success in intubating a seated intubation in patients whose cervical spines were
ries of 100 patients, including several cases in which stan- immobilized provided evidence of a significantly shorter
dard blades had provided a poor view of the larynx.1 No time to intubation with the Airtraq, with the only failure
comparative trials of prisms are available. The efficacy of of intubation occurring in the MacIntosh group.7
these devices has been established only anecdotally. In his
original description of the device, Huffman3 reported he
was able to effectively visualize the glottic opening with Preparation
the prism device in each of 35 patients, including those
with large, protuberant teeth. The Belscope’s effectiveness ● Standard preparations for DL
was evaluated by its originator, after whom it is named, ● If a prism (Huffman) or a mirror (Siker) is to be used, they
and has been applied successfully in patients with normal should be placed for several minutes in warm water to
anatomy as well as those with difficult airways.8 Bellhouse avoid fogging, or a defogging solution should be applied.
reported his experience with more than 3,500 intuba- ● The Airtraq should be opened and defogger applied, or
tions using his blade and reported it “wholly successful.” in case of emergency proceed to laryngoscopy. An ETT
In 12 cases of failure of the Mac blade, and 7 cases of should be placed in the coaxial channel of the device.
DESIGN SERVICES OF

Procedure ● portable, but they can easily be scratched and small prisms
are frequently misplaced
● not familiar; requires practice in vivo and in vitro espe-
MIRROR (Figs. 16-6 and 16-7)
● attach Siker blade to laryngoscope handle
cially with the inverted images from the mirror blades
● perform DL AIRTRAQ
● note inverted image...etc ● relatively inexpensive for a "video " type blade
● portable and self-contained

PRISM (Figs. 16-8 and 16-9)
● disposable single use (may be an advantage or a disad-
● place prism on vertical flange of Mac blade (Fig. 16-3)
● repeat laryngoscopy, using view through prism to bring

vantage)
● does not require warming or defogging procedure
glottis into view (Fig. 16-9)
● in addition to the subheading issue above the airtraq sec-
tion of "procedure" needs to be broken up as such: Indications

AIRTRAQ (Figs. 16-10 and 16-11) ● Poor laryngoscopic view (grade 3 or 4 view).
● insert the device in the midline, following the curve of the
blade
● with eyepiece perpendicular to the ground, lift the device
Contraindications
up away from the bed (Fig. 16-10)
● center the vocal cords in the viewfinder (Fig. 16-11)
● Usual contraindications to DL
● if the cords are not visible, tilt the eyepiece toward the
● Lack of familiarity with devices
feet, effectively withdrawing the device incrementally, and
then return to perpendicular and repeat the lifting proce-
dure
Complications
● when a view of the laryngeal inlet is evident and cen- ● Similar to those of DL
tered in the eyepiece, push the ETT out of its channel and ● Inability to place ETT using inverted image (with the
through the vocal cords mirror blades)
● Fogging of mirror or prism obscuring image
Practicality
Acknowledgments
MIRRORS AND PRISMS
● inexpensive
Airtraq photos by David Pinkerton
● simple in concept
F I GUR E 1 6 -6 Insertion of the Siker blade into

the mouth. Note the relatively high vertical profile
of the blade.
DESIGN SERVICES OF

CHAPTER 16 ■ MIRROR BLADES AND PRISM BLADES 131
FIG U RE 16-7 Grade 2 view of the glottis as

reflected in the mirror of the Siker blade.
FIG U RE 16-8 A poor view of the larynx

using DL with 3 Mac not viewed through the
prism.
FIG U RE 16-9 Laryngoscopy with prism on

3 Mac blade, showing view through prism:
the airway is evident as grade 2 view.
DESIGN SERVICES OF

F I GUR E 1 6 -1 0 Performing laryngoscopy

with the Airtraq. Note the need for the operator
to place his eye in contact with the device.
F I GUR E 1 6 -1 1 Grade 1 view of the glottis

through the viewfinder of the Airtraq.
REFERENCES risk for difficult tracheal intubation. Anaesthesia. 2008;

63:182–188.
1. Siker ES. A mirror laryngoscope. Anesthesiology. 1956;17: 6. Ndoko SK, Amathieu R, Tual L, et al. Tracheal intubation
38–42. of morbidly obese patients: a randomized trial compar-
2. Neustein SM. The Neustein laryngoscope: a new solution to ing performance of Macintosh and Airtraq laryngoscopes.
the difficult intubation. Anesth Rev. 1992;19:54–59. Br J Anaesth. 2008;100(2):263–268.
3. Huffman JP. The application of prisms to curved laryngo- 7. Maharaj CH, Buckley E, Harte BH, et al. Endotracheal in-
scopes. J Am Assoc Nurse Anesth. 1968;36:138–139. tubation in patients with cervical spine immobilization:
4. Bellhouse CP. An angulated laryngoscope for routine and dif- a comparison of Macintosh and Airtraq laryngoscopes.
ficult tracheal intubation. Anesthesiology. 1988;69:126–129. Anesthesiology. 2007; 107:53–59.
5. Maharaj CH, Costello JF, Harte BH, et al. Evaluation of the 8. Mayall RM. The Belscope for management of the difficult
Airtraq and Macintosh laryngoscopes in patients at increased airway. Anesthesiology. 1992;76:1059–1060.
DESIGN SERVICES OF

CHAPTER
Bougies and Airway Stylets 17 cn
Pranav Shah and Erin Sullivan
Concept Evidence
During unanticipated difficult intubations, emergen- Numerous case reports and case series attest to the value
cies, or when direct laryngoscopy provides a poor view of the bougie in difficult intubations in the operating room
(Cormack-Lehane Grade III) or reveals a very tight glottic (OR), emergency department, and in the prehospital set-
opening, it is often beneficial to insert a guiding catheter ting. A significant proportion of these studies were carried
(“gum elastic bougie” or GEB) prior to attempting endo- out in the United Kingdom.
tracheal tube (ETT) placement. There have been several papers that have elucidated
The GEB provides several advantages. It has improved optimum technique for GEB use. Dogra et al identified
maneuverability compared with an ETT. The GEB’s combi- several steps that increased success using GEB. These
nation of firmness and an angulated tip provides a means included keeping the laryngoscope blade in the mouth
to intubate the glottic opening when it is poorly visualized, during ETT placement and rotating the tube 90° counter-
if its location can be inferred from the view of the interary- clockwise if the ETT became lodged at the glottic open-
tenoid notch or the position of the epiglottis. Additionally, ing.1 Additionally, Latto et al collected data on 200 cases
the GEB can provide a tactile clue that it has been placed of GEB use by anesthesiologists in the United Kingdom
correctly in the airway, as its stiff end often moves against between October 1997 and August 1998. Of 200 uses,
the cartilagenous tracheal rings. Of note, the GEB can pro- 146 were for “poor view of the larynx” and 46 for “dif-
vide a second form of tactile feedback because continu- ficulty pushing the tube toward the larynx.” Their survey
ing to insert the bougie will lead to resistance if placed in revealed that 178 cases were intubated on first try with
the trachea. This resistance occurs when the angled tip of GEB and 15 on the second attempt. Six required more than
the bougie is too wide to fit through the narrowing bron- two attempts, and one attempt at inserting GEB failed.
chi. It usually occurs at an insertion depth of 30–35 cm. Moreover, “clicks” of the tracheal ring were present in 65%
Generally, no resistance is felt if placed in the esophagus. of cases (130) and only 13% had distal resistance. They
The malleable Eschmann introducer with its stiff, an- recommended that the distal end of the GEB be further
gulated distal tip lends itself to this task because it is small bent to a more acute angle prior to use, as well as insert-
enough to be maneuvered in the pharynx where it is used ing the GEB to 45-cm depth before declaring that the de-
to “probe” for the glottic opening. Its end is firm enough vice had encountered no resistance and hence was likely
to rattle against the tracheal rings as it is placed in the in the esophagus. Furthermore, their survey revealed that
airway, providing a sense of correct placement. This type in 45% of the cases laryngeal pressure improved the view
of introducer is 60 cm long, 5 mm in diameter, with distal of the glottic opening, and in 51% there was no change,
2.5 cm angulated at approximately 40°. It has markings whereas it worsened the view in only 2% of cases. Hence,
for every 10 cm. they also recommend optimum positioning of the patient
The Frova intubating introducer similarly facilitates along with attempted laryngeal pressure as part of their
intubation when the glottic view is poor. This device is a routine technique to obtain the best glottic view.2
hollow cannula with a malleable, removable steel stylet, Several case reports show GEB use increases success
which permits “jet” (high pressure) ventilation through in difficult airway scenarios. Combes et al trained 40 an-
an adaptor, or oxygen insufflation during intubation at- esthesiologists on a manikin over 2 months on a difficult
tempts. It is 65 cm long, 4.7 mm in diameter, with distal airway algorithm where GEB was the first line tool in a
2.0 cm angulated at 65°. The introducer comes with a rigid “can ventilate, cannot intubate” scenario. In the prospec-
stylet that is 10 cm shorter than the introducer thereby tive portion of the study over next 18 months, 89 sce-
decreasing the risk of trauma on insertion. narios occurred, and, in 80 cases, GEB allowed the ETT to
Airway exchange catheters can also be used as ETT be successfully placed.3 Komatsu et al examined the role
introducers. However, these devices lack a curved tip to of GEB in anesthetized patients with simulated restricted
provide tactile feedback regarding which lumen is being neck immobility using a cervical collar. There was a 90%
cannulated. intubation success rate using GEB. Of note, the authors
133

also reported a 100% success rate with a video laryngo- Procedure

scope.4 Nolan and Wilson studied intubation in 157 pa- (Figs. 17-2 to 17-5)
tients with manual cervical stabilization applied, and
found that with GEB, all 78 patients in the GEB group
● Proceed with direct laryngoscopy and establish best
were intubated in less than 45 seconds, and that GEB was
possible view (Fig. 17-2)
used successfully in the 5 intubation failures in the di-
● Attempt laryngeal pressure to see if it improves the glot-
rect laryngoscopy group5. Furthermore, Maruyama and
tic view
colleagues studied the difficulty of intubation using video
● Identify interarytenoid notch at the back of the glottis,
laryngoscope, GEB, and standard direct laryngoscopy in
if possible
manikins undergoing chest compressions with or without
● Place distal (angulated) tip of bougie above the notch,
manual cervical stabilization. These authors found that in-
or below the epiglottis
tubation via video laryngoscope was more readily accom-
● Probe for the opening of the glottis
plished than that with GEB, which in turn was easier than
● Gently insert bougie, feeling for tip against tracheal
standard direct laryngoscopy.6
rings (Fig. 17-3)
Moreover, several authors have examined GEB use
● If tip does not encounter rings, continue insertion.
outside the OR. Jabre et al evaluated GEB use in the pre-
(If using Frova introducer, remove stylet before continu-
hospital setting where intubation was necessary. After
ing insertion) (Figs. 17-1 and 17-2)
training on a manikin, intubation reports were collected
● At approximately 28 cm to 30 cm from teeth, the bougie
for the next 30 months. Of the 1,442 intubations, 41 at-
will encounter resistance as it enters one of the bronchi
tempts required GEB placement. It was successfully placed
and its tip encounters the smaller airways. If this does not
33 times (78%).7 Shah et al8 reported use of GEB during
occur by 35 cm, the bougie is usually in the esophagus
intubation for various reasons in 88 cases over 17 months
● Pull bougie back from resistance
in a large academic emergency medicine department and
● Have assistant place ETT over the proximal end of
reported a success rate of 80%. Also, some authors have
bougie
found GEB useful in modifying other airway techniques.
● Leave laryngoscope in place and elevate soft tissues
GEB also has been used to assist in cricothyrotomy in an
during advancement of the ETT
animal laboratory setting9 and in placing a Proseal laryn-
● The assistant then holds proximal end of bougie,
geal mask airway (in this technique, GEB was purpose-
preventing its advance, as the ETT is moved along it
fully placed in the esophagus to guide the LMA to an op-
toward the glottis (Fig. 17-5)
timal position).10
● If ETT insertion meets resistance, rotate ETT 90° either
The success of the Eschmann stylet has led to the de-
to the right or left as the leading edge of the ETT is likely
velopment of several different varieties of bougies. Braude
to get stuck at the glottic opening
et al11 compared several types in a simulated difficult air-
● Guide ETT into glottis, maintaining position of bougie
way and found that the Portex single use GEB was inferior
● Insert ETT to desired depth
to Sunmed, Greenfield, and Eschmann GEB. Janakiram
● Pull bougie back, remove from ETT
et al12 compared the Pro-Breath GEB (the new version of
● Inflate ETT cuff, confirm placement
Portex GEB), the Frova introducer, and the traditional
Eschmann GEB on manikins, and found the Eschmann
and Frova devices to be superior. Hodzovic et al13 also Practicality
examined various types of GEB and stylets in manikins
and found that the peak force applied at the distal tip was ● Simple concept, requires little practice
greater with Frova catheters than with Eschmann GEB. ● Relatively familiar
● Portable
Preparation For Direct ● Readily affordable
Laryngoscopy With Bougie
Or Airway Stylet (Fig. 17-1) Indications
● Anesthetized, preoxygenated patient, prepared for DL ● Poor laryngoscopy grade (Cormack-Lehane III)
(chapter 5) ● Small glottic aperture
● Lubricate bougie lightly ● Suspected cervical spine injury, in a patient requiring
● Enlist aid of an assistant intubation
DESIGN SERVICES OF

CHAPTER 17 ■ BOUGIES AND AIRWAY STYLETS 135
B
A
C D
F I GUR E 1 7 -1 A: Eschmann stylet (top) and Frova intubating stylet (bottom). B: Frova intubating introducer with stylet
removed. C: Frova intubating introducer with stylet removed and adaptor for high-pressure oxygen insufflation attached.
D: Frova intubating introducer with stylet removed and 15 mm adaptor for attachment to anesthesia circuit or resuscitation bag.
A B
F I GU R E 17 - 2 Laryngoscopic view prior to (A and B) and after the insertion of (C) Frova intubating. Arrowhead (Epiglottis).
Star (Glottic opening). Arrow (Posterior Cartilages). Double Arrows (Interarytenoid notch). Frova intubating introducer was
used in images B and C because the patient was known to have vocal cord paralysis of the right side leading to a small glottic
opening as noted on laryngoscopy during previous surgery. Patient underwent successful cordotomy.
DESIGN SERVICES OF

F I GUR E 1 7 -3 Midsagittal view of a cadaver during direct

laryngoscopy with insertion of bougie into trachea and an
ETT being inserted over the GEB. Note that in practice the
end of the GEB will often be advanced more distally in the
trachea before an ETT is inserted over the GEB to decrease
the chance of the GEB being dislodged from the tracheal
lumen. Often, ETT will meet resistance if the tip catches the
posterior cartilages. If the tip of the ETT meets resistance
(arrows) rotate ETT 90° and advance gently over the poste- T E
rior cartilages. T, tongue; E, epiglottis; P, posterior cartilage;
R
L, larynx; Tr, trachea; R, Tracheal ring.
L Tr
● Similar to those of direct laryngoscopy ● Misplacement of ETT into esophagus can occur
● Laryngeal disruption ● Tracheal rings may not be felt, even when placed cor-
● Inaccessibility of oral cavity rectly
● Trauma to larynx or bronchus may occur
● ETT can be advanced too far, into mainstem bronchus
DESIGN SERVICES OF

CHAPTER 17 ■ BOUGIES AND AIRWAY STYLETS 137
FIG U RE 17- 4 Midsagittal

view of a cadaver showing
bougie placed into esophagus
(no resistance would be met in
this situation as the bougie is
advanced). If bougie is inserted
into the esophagus, it can be ad-
vanced > 35 cm without meeting
resistance.
FIG U RE 17-5 A and B: Placing ETT over bougie with the help of
an assistant. Note that the laryngoscope is maintained in the mouth to
ease the passage of ETT, and the proximal end of bougie is fixed by the
assistant to prevent migration of bougie.
DESIGN SERVICES OF

REFERENCES 7. Jabre P, Combes X, Leroux B, et al. Use of gum elastic bou-

gie for prehospital difficult intubation. Am J Emerg Med.
1. Dogra S, Falconer R, Latto IP. Successful difficult intuba- 2005;23(4):552–555.
tion. Tracheal tube placement over a gum-elastic bougie. 8. Shah KH, Kwong B, Hazan A, et al. Difficulties with gum
Anaesthesia. 1990;45(9):774–776. elastic bougie intubation in an academic emergency depart-
2. Latto IP, Stacey M, Mecklenburgh J, et al. Survey of the use ment. J Emerg Med. 2010. [Epub ahead of print.]
of the gum elastic bougie in clinical practice. Anaesthesia. 9. Hill C, Reardon R, Joing S, et al. Cricothyrotomy technique
2002;57(4):379–384. using gum elastic bougie is faster than standard technique:
3. Combes X, Le Roux B, Suen P, et al. Unanticipated difficult a study of emergency medicine residents and medical stu-
airway in anesthetized patients: prospective validation of a dents in an animal lab. Acad Emerg Med. 17(6):666–669.
management algorithm. Anesthesiology. 2004;100(5):1146– 10. Brimacombe J, Keller C, Judd DV. Gum elastic bougie-guided
1150. insertion of the ProSeal laryngeal mask airway is superior to
4. Komatsu R, Kamata K, Hoshi I, et al. Airway scope and gum the digital and introducer tool techniques. Anesthesiology.
elastic bougie with Macintosh laryngoscope for tracheal in- 2004;100(1):25–29.
tubation in patients with simulated restricted neck mobility. 11. Braude D, Ronan D, Weiss S, et al. Comparison of available
Br J Anaesth. 2008;101(6):863–869. gum-elastic bougies. Am J Emerg Med. 2009;27(3):266–270.
5. Nolan JP, Wilson ME. Orotracheal intubation in patients 12. Janakiraman C, Hodzovic I, Reddy S, et al. Evaluation of
with potential cervical spine injuries. An indication for the tracheal tube introducers in simulated difficult intubation.
gum elastic bougie. Anaesthesia. 1993;48(7):630–633. Anaesthesia. 2009;64(3):309–314.
6. Maruyama K, Tsukamoto S, Ohno S, et al. Effect of cardio- 13. Hodzovic I, Latto IP, Wilkes AR, et al. Evaluation of Frova,
pulmonary resuscitation on intubation using a Macintosh single-use intubation introducer, in a manikin. Comparison
laryngoscope, the AirWay Scope, and the gum elastic bou- with Eschmann multiple-use introducer and Portex single-
gie: a manikin study. Resuscitation. 2010;81:1014–1018 use introducer. Anaesthesia. 2004;59(8):811–816.
DESIGN SERVICES OF

PART
Blind Intubation
IV
CHAPTER
Blind Nasotracheal Intubation 18 cn
Steve Orebaugh
Concept placement improved from 58% to 72% when a directional

tip control tube was used.3 BNTI in children is typically
reserved for cases in which other methods of intubation
Blind nasotracheal intubation (BNTI) remains a viable
are not feasible.4
technique in the elective surgical patient and in emer-
gency intubation, particularly for patients with challeng-
ing anatomy. In this procedure, an endotracheal tube Preparation
(ETT) is placed through one of the nares into the naso-
(Figs. 18-2 and 18-3)
pharynx (Fig. 18-1), then into the glottis, guided primar-
ily by breath sounds, without visualization. At its best, it
is a smooth, effective, and painless procedure. At its worst, ● Soften the ETT in a warmed saline solution, if time allows
BNTI is traumatic and uncomfortable and may make sub- (directional ETTs tend to be very soft and do not require
sequent attempts at airway management more difficult by this step)
causing epistaxis or vomiting. BNTI requires preservation ● Check the patency of each nostril, through inquiry and
of spontaneous ventilation, so that audible inspiratory ef- physical examination (occluding each side and asking the
forts can be detected and synchronized with tube place- patient to breathe through the nose can be revealing)
ment. It is much less likely to be successful in the apneic ● Prepare the nose with local anesthetic gel or solution, and
patient. The breath sounds, when optimized, help to guide a vasoconstrictor (phenylephrine solution or oxymetazo-
the tube into a position just above the glottis, so that con- line nasal spray)
trolled advancement of the tube allows correct placement. ● Placement of successively larger nasopharyngeal airways,
Whistles are available to attach to the end of the ETT to coated with local anesthetic and vasoconstrictor, reduces
make ventilation through the ETT more audible, confirm- epistaxis in the elective situation
ing placement of the tube in the airway. BNTI is less likely ● Sedation or anesthesia may be provided, but spontaneous
to be used in children than in adults, due to the lack of respiration should be preserved
cooperation, the small size of the nares, and frequent hy- ● Patient may be supine, or in seated position
pertrophy of the adenoidal tonsils. ● Standard preparations should be made for direct laryngos-
copy (see Chapter 5)
Evidence
Procedure (Figs. 18-4–18-8)
BNTI is supported anecdotally by case reports and case
studies in both the emergency medicine and anesthesiol- ● Place ETT in nares (the right nostril is usually chosen,
ogy literature. In the National Emergency Airway Registry, to allow the bevel of the ETT to approach the turbinates
this method was used in about 5% of all intubations, with atraumatically)
a success rate of nearly 86%.1 In Dronen’s2 comparison ● The tube is directed along the floor of the nasal cavity,
of BNTI with direct laryngoscopy for intubations in the parallel to the hard palate
emergency department (ED), the 68% rate of successful ● Place an ear near the proximal end of the ETT, listening
endotracheal intubation was significantly lower than that carefully for breath sounds
for direct laryngoscopy, in which there were no failures. ● When the nasopharynx is reached, breath sounds become
In addition, complication rates, mostly nasal bleeding and audible
emesis, were much higher with BNTI. When paramedics ● Gentle advancement of the tube should allow an increase
used BNTI in 219 intubations, the rate of appropriate ETT in the sounds, as the glottis is approached
139

140 PART IV ■ BLIND INTUBATION
F I GUR E 1 8 -1 Sagittal section

through cadaver specimen, show-
ing floor of nasal cavity, turbi-
nates, and nasopharynx: the path
traveled by a nasotracheal tube.
F I G U R E 1 8 -2 Preparation for BNTI:

nasal airways, local anesthetic gel, and
topical vasoconstrictor solutions.
DESIGN SERVICES OF

CHAPTER 18 ■ BLIND NASOTRACHEAL INTUBATION 141
FIG U RE 18-3 Dilation of the nose with

nasal airways/lubricants/vasoconstricors.
FIG U RE 18-4 ETT insertion, along floor

of nose.
DESIGN SERVICES OF

F I GUR E 1 8 -5 ETT in position in the hypo-

pharynx: breath sounds should be maximally
audible.
F I GUR E 1 8 -6 Tube misdirection (too

far posterior). Neck extension will help
to align the tube with the glottis.
DESIGN SERVICES OF

CHAPTER 18 ■ BLIND NASOTRACHEAL INTUBATION 143
FIG U RE 18-7 Tube misdirection (too far an-

terior). In this setting, the tube may be palpable
above the thyroid cartilage. Neck flexion will
help to align the tube with the glottis.
FIG U RE 18-8 Correct position, advanc-

ing ETT into glottis.
DESIGN SERVICES OF

● If breath sounds diminish, suspect the tube is advancing Indications

into the esophagus; withdraw and redirect or change head
and neck position ● Anatomy that suggests difficult direct laryngoscopy
● When the breath sounds are maximal, the ETT is held ● Need for intubation while preserving spontaneous
in place
ventilation
● During the pause, breath sounds are carefully tracked ● Inaccessibility of the oral cavity
● The tube should then be advanced as inspiration is
initiated
● If successful, patients breathe through the tube and can- Contraindications
not phonate
● When unsuccessful, changes in head position may assist ● Coagulopathy
in correct tube placement: extension brings the tube for- ● Atresia of nares
ward, whereas flexion of the neck brings its tip posteriorly ● Other causes of nasal cavity obstruction
● Directional tubes, if used, allow the tube tip to be redi- ● Enlarged adenoids
rected ● Apneic patient (relative—procedure is less successful)
● If the tube moves into the piriform recesses, lateral to the ● Upper airway trauma or obstruction
glottis, on advance (sometimes palpable in the neck), ro- ● Facial or nasal trauma distorting nasal anatomy
tation of the tube can help to direct its tip medially, to- ● Major head trauma
ward the laryngeal orifice ● Suspected cervical spine injury
● Tube placement is confirmed in the usual fashion
Practicality Complications
● Turbinate injury or avulsion
● The technique is simple, portable, and easily affordable
● Nasal hemorrhage (may be severe)
● BNTI may not be familiar, as it is not as popular as it once
● Gagging, choking, emesis
was, so it may require practice to understand how to di-
● Aspiration of gastric contents
rect head and neck position changes to facilitate intuba-
● Misplaced ETT
tion, as well as to learn to take cues from breath sounds
● Pharyngeal trauma
● Laryngeal trauma
● Placement of tube intracranially
REFERENCES 3. O’Connor RE, Megarget RE, Schnyder ME, et al. Paramedic

success rates for blind nasotracheal intubation is improved
1. Walls RM, Gurr DE, Kulkarni RG, et al. 6294 Emergency with the use of an endotracheal tube with directional tip
department intubations: second report of the ongoing control. Ann Emerg Med. 2000;36:328–332.
National Emergency Airway Registry (NEAR) II study. Ann 4. Steward DJ. Manual of Pediatric Anesthesia. 4th ed. New
Emerg Med. 2000;36:S51. York, NY: Churchill-Livingstone; 1995:88.
2. Dronen SC, Merigian DS, Hedges JR, et al. A comparison of
blind nasotracheal and succinylcholine-assisted intubation
in the poisoned patient. Ann Emerg Med. 1987;16:650–652.
DESIGN SERVICES OF

CHAPTER
Blind Orotracheal Intubation 19 cn
Steve Orebaugh
Concept A. DIGITAL INTUBATION
When tools for laryngoscopy are unavailable or unreliable, Preparation

endotracheal tube (ETT) insertion may be facilitated by
using the fingers to guide the tube through the glottic
● Same as for direct laryngoscopy (see Chapter 5)
opening,1,2 or by the use of a device designed to guide
the tube through the oropharynx and into the glot-
● Double gloving adds a measure of protection
tis. Examples of the latter include the Williams airway
● Lubricate the stylet, place in the ETT
intubator and the Berman intubating airway.3,4 In digital ● Bend the ETT into a “field hockey stick” shape
intubation, the index and long fingers of the nondomi- ● The patient must be anesthetized and relaxed (to avoid
nant hand are placed in the hypopharynx, feeling for the trauma to the operator and to stimulate reflexes with
epiglottis anteriorly. They are then used to elevate and coughing or emesis) or unconscious
guide the tip of the styletted ETT just under the epiglot- ● Either sniffing position or neutral head position are
tis, into the larynx. If reaching the epiglottis (at least) or acceptable
glottis (optimally) is not possible due to short fingers or ● Preoxygenate, if time allows
a deep larynx, the technique will be much less reliable
and essentially becomes a blind thrust toward the glottis.
With the Williams or Berman guides, the device is inserted Procedure (Figs. 19-1–19-4)
into the mouth of the anesthetized or unconscious patient
and the tube inserted blindly through it to be guided ● Stand beside the patient, facing the top of his/her head,
toward the glottis. with the nondominant hand closest to the head
● The index and long fingers of the nondominant hand are
placed into the oropharynx
Evidence ● The epiglottis is palpated and lifted with the fingers
● If the epiglottis cannot be palpated, an assistant pulling on
Little systematic testing of these techniques has been
the tongue may elevate it to the point at which it can be
performed, nor are there useful comparative trials. Digital
palpated
intubation is most likely to be used when highly unfa-
vorable conditions for direct laryngoscopy exist, such
● The ETT is introduced and guided between the two fingers
as unavailability of a laryngoscope, copious amounts of
● The dominant hand advances the tube along the groove
blood or fluid in the airway, or the failure of all other tech- between the index and long fingers, curving around the
niques. It is more readily applicable in children than in base of the tongue
adults, due to the short distance between the mouth and ● While the index and long fingers guide the tube, it is ad-
glottis. Case reports attest to its utility in difficult pediatric vanced up under the epiglottis and into the glottis
airway management.5,6 The Williams airway has been used ● The stylet is removed, ETT cuff inflated, and tube place-
to provide blind orotracheal intubation in the operating ment is confirmed
room in more than 300 cases, with a success rate of 80%.4
145

FIGURE 19-1 Digital intubation

demonstrated in a cadaver specimen.
FIGURE 19-2 Fingers of nondominant hand,

thrust behind tongue, lifting epiglottis.

CHAPTER 19 ■ BLIND OROTRACHEAL INTUBATION 147
FIGURE 19-3 ETT insertion, guided

toward glottis by index and long
fingers.
FIGURE 19-4 ETT advancing

through glottis, guided by fingers.

F I GUR E 1 9 -5 Berman and Williams airways,

to facilitate blind orotracheal intubation.
F I GUR E 1 9 -6 Placement of Williams airway

in oropharynx in cadaver specimen.

CHAPTER 19 ■ BLIND OROTRACHEAL INTUBATION 149
FIG U RE 19-7 Advancing ETT through

Williams airway blindly into glottis.
● Alternatively, the index and long fingers of the nondomi- Procedure (Figs. 19-5–19-7)
nant hand can be inserted into the mouth with the curved,
styletted tube held between them ● Williams airway intubator is inserted, its distal extent
● As the fingers locate the glottis, the other (dominant)
curving around the back of the tongue
hand is used to advance the tube into the airway ● Lubricated ETT is inserted through the intubator
● The stylet is removed, ETT cuff inflated, and tube place- ● Tube is gently advanced into the glottis
ment confirmed ● If resistance is met, the ETT is withdrawn and the airway
intubator position modified, after which further attempts
B. BLIND INTUBATION THROUGH are conducted
A WILLIAMS AIRWAY INTUBATOR ● Once placed, ETT cuff is inflated, and its position is con-
firmed in the usual fashion
Preparation
Practicality
● Same as for direct laryngoscopy (see Chapter 5)
● Lubricate the ETT ● Simple, portable
● The patient should be anesthetized or unconscious, ● Little or no cost
preoxygenated, and in neutral position ● Unfamiliar to most—practice is desirable in patients or
cadavers

● Disrupted larynx, or severe oropharyngeal trauma (unless

Indications no alternative means of managing the airway exists)
● Conscious patient, or patient with intact airway reflexes
● Lack of laryngoscopy equipment
● Failure of other techniques
● Copious secretions or blood in the airway Complications
● Patient in position that precludes direct laryngoscopy
● Misplacement of ETT
● Trauma to pharynx or larynx from blind ETT insertion
Contraindications ● Injury to the hand of the person intubating (digital
technique)
● Inability to palpate epiglottis (digital technique)
● Inability to open the mouth
● Infectious process or foreign body of airway
REFERENCES 4. Williams RT, Harrison RE. Prone tracheal intubation

simplified using an airway intubator. Can Anaesth Soc J.
1. Stewart RD. Tactile orotracheal intubation. Ann Emerg Med. 1981;28:288–289.
1984;13:175–178. 5. Hancock PJ, Peterson G. Finger intubation of the trachea in
2. Murphy MF, Hung OR. Blind digital intubation. In: newborns. Pediatrics. 1992;89:325–327.
Benumof JL, ed. Airway Management: Principles and Practice. 6. Suetra PT, Gordon GJ. Digitally assisted tracheal intubation
St. Louis, MO: Mosby; 1996:277–281. in a neonate with Pierre Robin syndrome. Anesthesiology.
3. Berman RA. A method for blind oral intubation of the tra- 1993;78:983–985.
chea or esophagus. Anesth Analg. 1977;56:866–867.

PART
Lightwands and Optical Stylets
V
CHAPTER
Lightwands 20 cn
Anthony Silipo and Ryan Romeo
Concept and difficult airways.6 Yamamoto7 suggested in his

study of inexperienced intubators that approximately
30 intubations are required to become adept with the use
The lightwand places a light source at the tip of the
of lighted stylet technique. Ainsworth4 described intuba-
endotracheal tube (ETT). After the lightwand is threaded
tion using the lighted stylet within 60 seconds in 200 pa-
through the tube, the two are advanced blindly into the
tients under general anesthesia, whereas Weis8 reported
pharynx, aiming for the glottis. A “halo” of light visible
a series of 250 patients in whom he had 99% success in
over the front of the neck provides guidance for insertion
intubation using this device. In 950 surgical patients, use
of the tube and lightwand into the glottis, using gentle
of the Trachlight was compared with direct laryngoscopy
probing or rocking maneuvers. Transillumination of the
for efficacy in tracheal intubation.5 Direct laryngoscopy
larynx confirms that the tube is indeed being advanced
was found to require more time, produce more compli-
into the airway.
cations, and result in a higher failure rate (3% vs. 1%). In
In the late 1950s, Yamamura1 described transillumi-
addition, Tsutsui9 found in a series of 305 patients that
nation for use in nasotracheal intubation. The use of the
lighted stylet intubation with the Trachlight resulted in
lighted stylet, or lightwand, has been well described since
less of a blood pressure response as compared with di-
then, as a blind technique in the setting of difficult laryn-
rect laryngoscopy. In 186 documented difficult airway
goscopy, as well as for routine airway management.2–4 Early
patients, Hung10 used the Trachlight lighted stylet for
commercial lightwands suffered from poor illumination
intubation after induction of anesthesia with 99% suc-
and misdirection of the light, so that a darkened room was
cess. In 2009, 60 patients with high Mallampati score
necessary to see the halo produced in the glottic area dur-
were studied by Rhee et al in a prospective randomized
ing insertion into the airway. The lamp switch was often
comparison of lighted stylet and direct laryngoscopy in-
placed in an awkward position. Further, an overly rigid
tubation techniques. The authors demonstrated shorter
stylet could cause retraction of the ETT out of the glottis
intubation times and a higher first attempt success rate
when the lightwand was withdrawn.2 Newer models have
as well as smaller alterations in blood pressure in the
improved upon the visibility of the light, as well as the
lighted stylet group as compared with the direct laryn-
ergonomics of the device.5 The Trachlight (Laerdal, Long
goscopy group.11
Beach, CA), with its three-piece retractable wire lighted
In the emergency department (ED), lighted stylets
stylet, facilitates advancement of the lightwand-ETT and
have also proven useful for airway management in facial
makes it unlikely that the ETT will be withdrawn from
trauma and appear to facilitate intubation while preserv-
the trachea when the Trachlight device is pulled back.
ing immobility of the cervical spine.12,13 In a series of
A locking device for the proximal portion of the ETT, and
28 trauma patients with suspected cervical spine injury,
an adjustable length to accommodate different size tubes,
the lightwand was employed for intubation with 100%
also represent significant improvements of the Trachlight
success.14 The device has been adapted for nasotracheal in-
over earlier lighted stylets.5
tubation as well as orotracheal use.12,15 In prehospital care,
Vollmer3 reported the use of the lighted stylet by emer-
gency medicine residents in 24 patients with 88% success
Evidence in less than 45 seconds.
The lightwand has been recommended for use in
In the operating room (OR), lighted stylet intuba- patients with known or potential cervical spine injury,
tion has proven reliable and highly successful in both as its use requires little or no motion of the cervical
adults and children, in routine airway management spine. Turkstra et al16 evaluated cervical spine motion
151

152 PART V ■ LIGHTWANDS AND OPTICAL STYLETS
fluoroscopically in a crossover study of 36 healthy pa- ● Ensure the proximal end of the ETT is held by the lock-
tients undergoing intubation with in-line immobili- ing mechanism of the stylet, so that it does not slide up
zation. The authors compared the lighted stylet with and down
intubation with the MacIntosh laryngoscope blade or ● Bend the lightwand-ETT into a “field hockey stick” con-
use of a stylet during direct laryngoscopy and found figuration (90° to 120° bend proximal to cuff), 6.5 cm to
the least cervical spine motion occurred with the use 8.5 cm proximal to the tip of the lightwand
of the lighted stylet for intubation. In addition, Konishi ● Anesthetized, preoxygenated patient, with airway reflexes
et al11 also demonstrated less cervical spine movement controlled
radiographically in 20 ASA 1 and 2 patients while using ● Head in neutral position
the lighted stylet intubation as compared with con- ● Placing the illuminated stylet on the inside of the patient’s
ventional laryngoscopy. Inoue et al randomized 148 cheek approximates the halo of light sought with laryn-
patients undergoing intubation during general anesthe- geal transillumination
sia, with in-line immobilization of the cervical spine, to ● Stand at the head of the patient
intubation with the lighted stylet or with the intubating
laryngeal mask airway (LMA). The authors reported a
97% success with the Trachlight lightwand (Laerdal), Procedure for Lightwand
versus 73% for the intubating LMA, and concluded that (Figs. 20-2–20-8 and 20-11)
the lightwand was more advantageous for orotracheal
intubation in a population with known or potential cer- ● Grasp/advance the mandible with the nondominant hand
vical spine disorders.17 ● Insert lighted stylet (with light on) over back of tongue
The importance of the “bent length” (site of bend- ● Make attempts to advance into glottis, searching for open-
ing of the lighted stylet into a “hockey stick” shape) has ing by gently advancing the tube/stylet repeatedly toward
recently been evaluated.18 Chen et al19 evaluated recom- the larynx in a “rocking” motion
mendations that the Trachlight device should optimally be ● If resistance is met, head extension, or jaw thrust may be
bent 6.5 cm to 8.5 cm proximal to its distal tip. Based on helpful to facilitate glottic entry
clinical practice, the authors relate the optimal bent length ● Halo of light over larynx confirms glottic entry
to be the thyromental distance (TMD), that between the ● Lack of halo, or halo in wrong site, provides cues to
patient’s thyroid cartilage prominence and the angle of the location of lightwand-ETT
mandible. They report that for patients with TMD greater ● When halo appears, advance the ETT, holding stylet in place
than 5.5 cm, the existing recommendations work well to ● If transillumination cannot be visualized in larynx, con-
optimize intubation success with the Trachlight device. sider reducing ambient light
However, for smaller patients, with TMD ≤5.5 cm, a bent ● Remove stylet while holding ETT, inflate ETT cuff, confirm
length at the lower range of the recommendation (6.5 cm) ETT placement (see PHOTO)
should be used.
Procedure for Trachlight

Preparation Device (Figs. 20-9 and 20-10)
● Usual arrangements for orotracheal intubation (Fig. 20-1) ● With Trachlight device, enter glottis in same fashion
(Chapter 5) (using transillumination)
● Lightwand prepared, lubricated, battery checked ● Retract wire stylet upon glottic entry
● Thread ETT over wand, until the distal tip with light ● Advance tube and Trachlight further into the glottis, until
bulb is at the end of the endotracheal tube (but not transillumination is noted in the lower neck, to level of
protruding) sternal notch

CHAPTER 20 ■ LIGHTWANDS 153
FIG U RE 20-1 A. Lighted stylet with ET Tube,

and B, close up of tip showing incorrect posi-
tion with stylet inserted beyond tip of ET tube.
In C, the correct position of the stylet in ET tube
is shown.

F IG U R E 2 0 -2 Insertion of
lightwand-ETT into oropharynx in
cadaver specimen.
F IG U R E 2 0 -3 Lightwand-ETT
approaching glottis.

FIG U RE 20-4 Lightwand-ETT advanced

into airway.
FIG U RE 20-5 Insertion of

lightwand-ETT.

F I GURE 2 0 -6 The lightwand is advanced

into the hypopharynx.
F I GU R E 2 0 -7 A, B, C: Halo of light
produced by lightwand-ETT in both sides
of esophagus, and in larynx.

FIG U RE 20-8 A and B: A “rocking”

motion is made with the lightwand to
facilitate glottic entry.

F IG U R E 2 0 -9 Trachlight: ETT
loaded, locked into position.
F IG U R E 2 0 -1 0 Trachlight: insertion
of ETT into pharynx.
● Unlock the collar around the ETT adaptor ● Not a familiar technique; requires some training
● Advance the ETT off the stylet ● Older models produce a poor halo and require a dark
● Grasp the ETT firmly room
● Remove the stylet, inflate ETT cuff, confirm tube placement ● Very obese patients may render this technique ineffectual
Practicality Indications
● Simple, portable ● Difficult laryngoscopy

● Trachlight is more complex; requires some practice and ● Copious secretions or blood in airway
familiarity with its components ● Routine intubation
● Affordable: the usual lightwand is $35 and the ● Potential or known cervical spine injury in patient
Trachlight is $80 requiring airway management

FIG U RE 20-11 Removal of stylet

from ETT.
● Laryngeal trauma ● Misplaced ETT due to misinterpretation of halo effect

● Hypoxic patient who cannot be ventilated (time prohibits) ● Inadvertent withdrawal of ETT from larynx when lighted
● Obstruction or distortion of upper airway anatomy stylet is pulled back
● Grossly obese patients (body mass index > 30 reduces ● Inability to see transillumination in obese patients
likelihood of success) ● Inability to advance ETT despite transillumination
● Insufficient anesthesia/lack of control of airway reflexes ● Trauma to larynx or pharynx from blind probing
● Regurgitation/aspiration
● Hoarseness

REFERENCES 12. Weis FR. Lightwand intubation for cervical spine injuries.
Anesth Analg. 1992;74:619–623.
1. Yamamura H. Device for blind intubation. Anesthesiology. 13. Verdile VP, Heller MB, Paris PM, et al. Nasotracheal intuba-
1959;20:221. tion in traumatic craniofacial dislocation. Am J Emerg Med.
2. Davis L, Cook-Sather SD, Schreiner MS, et al. Lighted stylet 1988;6:39–41.
tracheal intubation. Anesth Analg. 2000;90:745–756. 14. Hauswald M, Sklar DP, Tandberg D, et al. Cervical spine
3. Vollmer TP, Stewart RD, Paris PM, et al. Use of a lighted movement during airway management. Am J Emerg Med.
stylet for guided orotracheal intubation in the prehospital 1991;9:535–538.
setting. Ann Emerg Med. 1985;14:324–328. 15. Verdile VP, Chiang JL, Bedger R, et al. Nasotracheal in-
4. Ainsworth QP, Howells TH. Transilluminated tracheal intu- tubation using a flexible lighted stylet. Ann Emerg Med.
bation. Br J Anaesth. 1989;62:494–497. 1990;19:506–510.
5. Hung OR, Pytka S, Morris I, et al. Clinical trial of a new 16. Turkstra TP, Craen RA, Pelz DM, et al. Cervical spine
lightwand device to intubate the trachea. Anesthesiology. motion: a fluoroscopic comparison during intubation with
1995;83:509–514. lighted stylet, Glidescope, and MacIntosh laryngoscope.
6. Davis L, Cook-Sather S, Schreiner MS. Lighted stylet tracheal Anesth Analg. 2005;101:910–915.
intubation: a review. Anesth Analg. 2000;90:745–756. 17. Inoue Y, Koga K, Shigematsu A. A comparison of two tra-
7. Yamamoto T, Aoyama K, Takenaka I, et al. Light-guided cheal intubation techniques with Trachlight and Fastrach
tracheal intubation using a Trachlight: causes of difficulty in patients with cervical spine disorders. Anesth Analg.
and skill acquisition. Masui. 1999;48(6):672–677. 2002;94:667–671.
8. Weis FR. Intubation by use of a lightwand. J Oral Maxil 18. Wong SY, Coskunfirat ND, Hee HI, et al. Factors influenc-
Surg. 1989;47:577–581. ing time of intubation with a lightwand device in patients
9. Tsutsui T, Setoyama K. A clinical evaluation of blind orotra- with known airway abnormality. J Clin Anesth. 2004;16:
cheal intubation using Trachlight in 511 patients. Masui. 326–331.
2001;50(8):854–858. 19. Chen T-H, Tsai S-K, Lin C-J, et al. Does the suggested
10. Hung OR, Stevens SC, Pytka S, et al. Clinical trial of a new lightwand bent length fit every patient? The relation be-
lightwand device for intubation in patients with difficult tween bent length and the patient’s thyroid prominence-
airways. Anesthesiology. 1998;79:A48. to-mandibular angle distance. Anesthesiology. 2003;98:
11. Rhee KY, Lee JR, Kim J, et al. A comparison of lighted 1070–1076.
stylet (Surch-Lite) and direct laryngoscopic intubation
in patients with high Mallampati scores. Anesth Analg.
2009;108(4):1215–1219.

CHAPTER
Optical Stylets 21 cn
Stephen Esper and Steve Orebaugh
Concept the ETT to 28 cm in order to fit onto the stylet. This short
length facilitates ready positioning of the device in front
of the operator’s eye during the process of direct laryngos-
Through the use of fiberoptic light and image bundles,
copy when a challenging view is evident. There is a site for
optical stylets permit the user to obtain a view from the
an oxygen connector to insufflate oxygen. Lightwand-like
distal end of the endotracheal tube (ETT). The stylets al-
transillumination is also available as well.
low direct visualization of structures at the tip of the tube
The Bonfils Retromolar Intubation Fiberscope (Karl
as it is inserted, simplifying intubation when a poor laryn-
Storz Endoscopy, CA) was derived from the work of Bonfils1
goscopic grade is encountered and facilitating confirma-
in which he described an approach from a very lateral po-
tion of tube placement (Figs. 21-1–21-4). Because of the
sition, behind the molar teeth, to intubate children with
bright light at the tip of the device, the optical stylet can
Pierre Robin syndrome. The device is a traditional rigid
also act as a lightwand if visualization through the optics is
optical stylet with a fixed 40° angulation at the distal end,
poor. These devices require the operator to look through
which can be illuminated by either a remote or attachable
an objective lens as the device is inserted into the airway.
(battery-powered) Xenon light source. The smallest ver-
Optical stylets are frequently used in conjunction with di-
sion allows placement of a 4.0 mm internal diameter ETT.
rect laryngoscopy, or a jaw thrust, elevating the mandible
Another device, the Sensascope (Acutronic MS,
and tongue for optimum visualization. In essence, this is a
Hirzel, Switzerland), combines some features of an optical
simpler and less expensive version of the fiberoptic intu-
stylet and a fiberoptic scope. The Sensascope has a rigid,
bating bronchoscope.
S-shaped shaft that is 6 mm in diameter, with a distal,
3-cm steerable tip, as well as a built-in camera and LED
light source. The image is displayed on a separate video
Types of Stylets monitor, rather than observed through an eyepiece. For
optimal function, the device is recommended to be used
There are multiple types of optical stylets in use. Some of with direct laryngoscopy to retract the tongue and soft tis-
the most common include the Shikani Optical Stylet, the sues before insertion into the pharynx.
Levitan (First Pass Success or FPS) Optical Stylet, and the Some seeing-stylet type devices do not have the rigidity
Bonfils Retromolar Intubation Fiberscope. These optical of the above devices but nonetheless allow visualization of the
stylets are used in different situations and the insertion anatomy at the tip of an inserted ETT. The “Pocket Scope”
technique differs among the classes. (Clarus Medical, Minneapolis, MN) is a flexible, 42 cm shaft
The Shikani Optical Stylet (Clarus Medical, that is 3.3 mm in diameter and which is illuminated by an
Minneapolis, MN), like the lighted stylet and the other op- attachable “green line” laryngoscope handle. The device is
tical stylets discussed below may be used for routine airway used to rapidly confirm the placement of an ETT or a double
management. In addition, this device is useful for situations lumen ETT, with less complexity and expense than a stan-
in which a difficult airway is anticipated or in urgent situa- dard fiberscope. Because of its flexibility, it would not be par-
tions when a patient presents an unanticipated challenging ticularly useful for intubation in a difficult airway situation.
or difficult airway (as long as ventilation is successful and The Tracheoscopic Ventilation Tube (TVT, ET View, Misgav,
the patient is not hypoxemic).Referred to as a “seeing bou- Israel) is an ETT, available in sizes 7, 7.5, and 8 mm internal
gie,” the Shikani stylet is a malleable device that is able to diameter, with a miniature camera and light source imbedded
conform to the patient’s airway. at the distal tip, which connects to a video monitor. It permits
The Levitan FPS Optical Stylet (Clarus Medical, ready confirmation of ETT placement and continuous moni-
Minneapolis, MN) is a device that is intended for use in toring of ETT position in the airway. In addition, this device
concert with direct laryngoscopy, when little or none of facilitates viewing the glottis in the setting of unfavorable
the glottic opening can be visualized. It has a shorter tube anatomy during direct laryngoscopy and, with the maneuver-
length to allow the ETT to be fitted directly to the device ability afforded by a standard stylet in the tube, would permit
without the need for a tube stop and requires cutting off one to steer the tube more effectively to the glottic opening.
161

F I G U R E 2 1 -1 Shikani Optical Stylet.
F IG U R E 2 1 -2 Insertion of optical
stylet-ETT behind the tongue in a
cadaver specimen.
Evidence airway management in the OR. In a study of 32 patients

undergoing elective anesthesia for surgery, 94% of cases
were intubated successfully on the first attempt and the
Optical stylets have been used for difficult and routine
remainder on the second attempt using this device.3
intubation in the operating room (OR).2–4 The optical
Gravenstein4 compared the fiberoptic stylet with direct
stylet has not been subjected to controlled, compara-
laryngoscopy and with bronchoscopic intubation in
tive studies in the management of the difficult airway.
75 patients undergoing general anesthesia, evaluating the
At the same time, in small series, it has proven useful for

CHAPTER 21 ■ OPTICAL STYLETS 163
FIG U RE 21-3 Optical stylet-ETT

advanced to glottis.
FIG U RE 21-4 Tip of optical stylet-ETT

placed into larynx.

time required for intubation, the quality of the view of the this must be weighed against the higher failure rate with
glottis, and the frequency of complications. The author the OS and the increased time required for intubation with
noted a shorter time for intubation using the fiberoptic this device OS (OS:28 ⫹/⫺ 17 seconds, MacIntosh blade
stylet than for the bronchoscope and a lower rate of post- 17⫹/⫺ 7 seconds ).10 There are multiple case reports, case
operative sore throat than direct laryngoscopy. However, series, and letters to the editor detailing the successful use
the least favorable laryngoscopic view occurred with the of the Shikani or Levitan Stylet to facilitate intubation of
fiberoptic stylet. When compared with intubation with patients with a difficult airway in both the pediatric and
direct laryngoscopy using an Eschmann stylet in simu- adult after attempts at direct laryngoscopy had failed.7,11
lated grade 3 laryngoscopy in a mannequin model, Biro5 In 2009, Paladino et al12 published a pilot study in sheep
described 100% success using the fiberoptic intubating detailing the successful and rapid use of the optical stylet
stylet in tracheal tube placement by 45 anesthetists in for a cricothyroidotomy procedure.
225 intubations, whereas there was a 40% rate of tube
misplacement (20% esophageal, 20% endobronchial)
using direct laryngoscopy under these circumstances.
Several small series attest to the utility of the optical
Preparation
stylet in children with known, suspected, or simulated dif-
ficult airways.6–8 Weiss et al6 described use of the optical ● Usual arrangements for orotracheal intubation (see
stylet in 50 pediatric patients undergoing induction of gen- Chapter 5)
eral anesthesia, with a simulated grade 3 laryngoscopy. The ● Check optical stylet view through objective (or on video
intubators were eight nurse anesthetists without prior ex- screen)
perience with this device. The authors reported a 92% suc- ● Lubricate external surface of stylet
cess rate (intubation within 60 seconds) in this population. ● Apply defogging solution to tip of stylet (or warm it)
In 2006, Evans et al compared an optical style versus gum ● Insert stylet into ETT and configure it into a “hockey
elastic bougie for intubation in manikins with a difficult stick” shape (Fig. 21-1)
airway. Forty-four anesthesiologists assessed Cormack ● Anesthetized, or unconscious, preoxygenated patient in
Grade III airways and used both direct laryngoscopy with neutral position
a gum bougie for tube placement, and an optical stylet. The ● Stand at head of patient
time to intubation was significantly shorter with the optical
stylet. Additionally, esophageal intubation was much less
frequent with the optical stylet.9 Turkstra et al published Procedure for use of Shikani
a crossover randomized controlled trial with 24 patients Optical Stylet (Clarus Medical)
comparing fluoroscopic evidence of cervical spine mo- (Figs. 21-2–21-8)
tion during intubation using either the optical stylet or
MacIntosh laryngoscope. The optical stylet (OS) produced ● Open mouth, lift mandible with nondominant hand, or
less cervical spine motion than direct laryngoscopy, but control tongue with direct laryngoscopy
F IG U R E 2 1 -5 Shikani Stylet with

ETT as it is placed in mouth.

CHAPTER 21 ■ OPTICAL STYLETS 165
FIG U RE 21-6 A jaw thrust facilitates

visualization of the glottis (direct laryngoscopy
may also be used).
FIG U RE 21-7 Guiding the tip of the optic

stylet into the glottis while visualizing position
in the hypopharynx.
FIG U RE 21-8 Removal of optic stylet while

ETT is firmly grasped and held in place.

● Insert tip of optical stylet at back of tongue in midline

● Establish jaw thrust (with assistant) or provide direct la-
Indications
ryngoscopy to move soft tissues off back of pharynx
● View structures at base of tongue/hypopharynx through ● Difficult laryngoscopy
stylet ● Cervical spine injury, in patient requiring airway
● Locate glottic opening management
● Advance tip of tube into glottis under direct visualiza-
tion Contraindications
● Confirm presence in airway with view of tracheal rings
● Firmly grasp ETT (or have assistant do so) ● Inaccessibility of oral cavity
● Remove stylet device from ETT ● Copious secretions or blood in airway
● Inflate ETT cuff, confirm ETT position, and fix in place ● Upper airway obstruction
Practicality ● Severely hypoxic patient who cannot be ventilated (due to
time constraints)
● Simpler than fiberoptic bronchoscope (FOB) intubation
● Expensive, but less so than FOB (approximately Complications
$2,000)
● Portable ● Fogging of instrument with reduced view
● Not familiar; requiring practice before use in emergency ● Laryngeal or pharyngeal trauma
situation ● Poor visualization/inability to place tube
● Viewing characteristics less favorable than FOB ● Tube misplacement
● Less useful for nasal intubation than FOB ● Regurgitation/aspiration
REFERENCES 7. Shukry M, Hanson RD, Koveleskie JR, et al. Management

of the difficult pediatric airway with Shikani Optical Stylet.
1. Bonfils P. Difficult intubation in Pierre-Robin chil- Paediatr Anaesth. 2005;15:242–245.
dren, a new method: the retromolar route. Anaesthetist. 8. Pfizner L, Cooper MG, Ho D. The Shikani Seeing Stylet for
1983;32:363–367. difficult intubation in children: initial experience. Anaesth
2. Weiss M. Video-intuboscopy: a new aid to routine and dif- Int Care. 2002;30:462–466.
ficult tracheal intubation. Br J Anaesth. 1998;80:525–527. 9. Evans A, Morris S, Petterson J, et al. A comparison of
3. Kitamura T, Yamada Y, Du H-L, et al. Efficiency of a new fi- the Seeing Optical Stylet and the gum-elastic bougie in
beroptic stylet scope in tracheal intubation. Anesthesiology. simulated difficult tracheal intubation: a manikin study.
1999;91:1628–1632. Anaesthesia. 2006;61(5):478–481.
4. Gravenstein D, Melker R, Lampotang S. Clinical assessment 10. Turkstra TP, Pelz DM, Shaikh AA, et al. Cervical spine mo-
of a plastic optical fiber stylet for human tracheal intubation: a fluoroscopic comparison of Shikani Optical Stylet vs
tion. Anesthesiology. 1999;91:648–653. Macintosh laryngoscope. Can J Anaesth. 2007;54(6):441–447.
5. Biro P, Weiss M, Gerber A, et al. Comparison of a new 11. Manoach S, Paladino L. Trauma airway salvage using
video-optical intubation stylet versus the conventional an optical stylet with oxygen insufflation. J Clin Anesth.
malleable stylet in simulated difficult tracheal intubation. 2008;20(4):317–318.
Anesthesiology. 2000;55:886–889. 12. Paladino L, DuCanto J, Manoach S. Development of a
6. Weiss M, Hartmann K, Fischer J, et al. Video-intuboscopic rapid, safe fiber-optic guided, single-incision cricothyrot-
assistance is a useful aid to tracheal intubation in pediatric omy using a large ovine model: a pilot study. Resuscitation.
patients. Can J Anaesth. 2001;48:691–696. 2009;80(9):1066–1069. Epub 2009 July 15.

PART
Retrograde Techniques
VI
CHAPTER
Retrograde Intubation 22 cn
Ryan D. Ball and David G. Metro
Concept to case reports and case series. RI has been described an-
ecdotally in several difficult airway situations, including
management of patients with obstructive sleep apnea,
This invasive technique allows for blind placement of an
facial trauma/burns, large oral cancers, spinal cord in-
endotracheal tube (ETT) over a guidewire or catheter that
jury, spine and joint disorders, oral infections, pharyngeal
is inserted percutaneously at the level of the cricothyroid
edema, angioedema, laryngeal carcinomas, and airway
membrane (CTM) or cricotracheal ligament. The wire is
anomalies.2,9,10 Barriot described its use by emergency phy-
then directed retrograde up into the pharynx, then into
sicians in the field, where it was employed successfully in
the mouth or nose. The procedure was originally de-
13 patients with severe maxillofacial trauma who could
scribed with the use of a red rubber catheter introduced
not be intubated by direct laryngoscopy in the prehospi-
through a tracheostomy and has evolved to include the
tal setting, and in another 6 patients in whom the tech-
use of a guidewire placed percutaneously and pulled ret-
nique was used electively.5 Its use has also been described
rograde, then placed through the lumen or Murphy eye of
perioperativley when fiberoptic intubation was either not
the ETT.1,2 Retrograde intubation (RI) can be performed
available or not feasible with success in 24 of 24 patients.6
with just a guidewire. However, because an ETT has the
In the hands of those who use the technique frequently,
potential to move laterally about a thin wire, and then
RI appears to have a high success rate. Of 383 applications
catch on the aryepiglottic fold or arytenoid cartilage as it
described in the literature by 1996, the technique was ef-
is inserted, the technique frequently incorporates a guide
fective in 98.5% of cases.2
catheter placed over a wire before the ETT is inserted.3
A potential complication of RI is failure of the ETT
The retrograde wire may also be retracted from the nose,
to advance into the trachea after the guidewire and guide
allowing for nasotracheal intubation. RI has been used
catheter are removed. Needle puncture at the cricotra-
successfully in pediatric difficult airways as well as those
cheal ligament, just distal to the cricoid cartilage, in-
of adults.2
creases the length of ETT in the larynx when the wire
is removed, increasing the likelihood that advancing the
Evidence tube into the trachea will be successful.11 Feeding the
guidewire through the Murphy eye, rather than the lu-
RI was first described by Butler and Cirullo4 in 1960 and men, of the ETT, can achieve a similar effect.12 A recent
has since been used effectively in patients with normal to study performed on fresh cadavers evaluated the impact
severely traumatized airways. The main benefits of this of a modified technique of RI to improve ETT guidance
technique over fiberoptic intubation or the newer video into the trachea.13 Lenfant et al described the removal
laryngoscopic techniques are that blood or secretions in of the guide catheter after introduction of the ETT into
the pharynx do not detract from successful intubation1,5 the larynx, leaving the guidewire and ETT in place. The
and that the equipment needed is inexpensive and read- guide catheter is then threaded through the ETT, along-
ily available. Although there are commercially available side the wire, and advanced into the trachea. The wire is
kits for RI, successful implementation of this technique removed and the ETT moved further into the airway. The
has been described with equipment as simple as a Touhy guide catheter is then removed from the proximal end of
needle and an epidural catheter.6 RI has been useful in the ETT. This modification did not require significantly
overcoming difficult airway anatomy in both the emer- more time to complete but resulted in a substantially
gency department (ED) and the operating room (OR).7,8 lower rate of failure of RI. A similar technique involves
However, the technique has not been widely applied in passing a bougie through the ETT before removal of
either setting. Data regarding its application are limited the wire.14
167

168 PART VI ■ RETROGRADE TECHNIQUES
● Create sterile conditions with skin antiseptic and sterile

Preparation for RI using Cook drapes
Inc, RI kit (Figs. 22-1 and 22-2) ● Anesthetize and preoxygenate patient (this technique
may also be carried out in the conscious patient, with
● Usual arrangements for tracheal intubation (see Chapter 5) local anesthetic injection translaryngeally to facilitate ETT
● Open and assemble RI kit (Cook Inc, Bloomington, IN) passage)
components ● Place patient in sniffing position with neck hyper-
● Palpate and mark cricoid cartilage extended
● Provide subcutaneous anesthesia with lidocaine (if time ● Stand at the patient’s side, with nondominant hand stabi-
allows, and patient can perceive pain) lizing and palpating the larynx
F I GUR E 2 2 -1 Components of Cook RI Kit

(needle and syringe, wire, guide catheter,
hemostat).
F I GUR E 2 2 -2 The CTM lies

between the cricoid and thyroid
cartilages, as indicated here.
The needle may also be inserted
below the cricoid cartilage, at the
cricotracheal ligament, which al-
lows a longer length of ETT to
enter the airway before the wire is
removed.
DESIGN SERVICES OF

CHAPTER 22 ■ RETROGRADE INTUBATION 169
Procedure for RI (Oral) ● Aiming 45° cephalad, puncture the CTM with needle/
(Figs. 22-2–22-13) catheter assembly and attached syringe
● The wire may also be introduced inferior to the cricoid
cartilage, through the cricotracheal ligament, to increase
● Maintain ventilation and oxygenation throughout the pro- the amount of the ETT that is in the larynx when the wire
cedure with bag-mask or, if breathing spontaneously, with is removed
a nasal cannula or simple face mask
FIG U RE 22-3 A and B: Needle insertion

in CTM.
DESIGN SERVICES OF

F I GURE 2 2 -4 Wire insertion through

thin-walled needle, retrograde into pharynx.
● Confirm needle is in airway by aspirating air into attached advance into larynx, then remove wire: catheter now
syringe acts as stylet to guide ETT past larynx into lower airway
● Remove needle, leaving catheter in airway (confirm (Fig. 22-13)
presence of catheter in airway by aspirating air freely ● Confirm ETT position
with syringe)
● Pass wire cephalad into pharynx and into mouth Practicality
● Secure wire with hemostat or manually and pull it out of
mouth ● Inexpensive
● Clamp the “tail” of the wire protruding from the CTM, ● Portable
so that it cannot inadvertently enter the airway ● Unfamiliar to most: requires preparation and practice
● Advance guide catheter over proximal end of the wire, ● Time is an issue: typically requires at least 2 minutes
into the mouth and pharynx, until it is palpable at CTM ● Not simple: multiple items are assembled; wires/catheters
● Maintain tension on wire, holding both ends (or clamp at
must slide without kinking or binding; one must identify
entry site into larynx with hemostat)
the entry point correctly; ETT can retract out of larynx
● As guide catheter enters larynx, the cannula used for wire
when it is advanced, after the wire has been removed
introduction will be pushed out of the skin at wire entry
site—the “turkey timer” method
● Place wire through distal lumen of ETT Indications
● Pass ETT over wire/guide catheter assembly, into pharynx
and glottis ● Predicted difficult airway
● Remove wire/catheter through mouth ● Copious secretions/blood in airway
● Alternatively, at this stage, remove guide catheter from ● Failure of other intubation techniques (with preserved
wire, place it through the ETT alongside wire, and ability to ventilate)
DESIGN SERVICES OF

FIG U RE 22-5 A and B: The wire

is grasped with a hemostat and
retrieved from the mouth.
DESIGN SERVICES OF

F I GUR E 2 2 -6 A and B: Guide

catheter inserted over wire.
DESIGN SERVICES OF

FIG U RE 22-7 As guide catheter reaches

CTM, the wire-introduction catheter is pushed
out of the skin.
FIG U RE 22-8 ETT is now

inserted over guide catheter.
DESIGN SERVICES OF

F I GUR E 2 2 -9 ETT is advanced along wire/

guide catheter, into larynx.
F I GUR E 2 2 -1 0 When the wire is inserted

into the distal lumen of the ETT, only a short
length of the ETT is in the larynx when it comes
to lie up against the CTM (This can lead to
ETT displacement out of larynx when wire and
guide catheter are removed.).
DESIGN SERVICES OF

FIG U RE 22-11 The wire and guide catheter

are removed, leaving the ETT in the larynx.
FIG U RE 22-1 2 Insertion of

needle at cricotracheal ligament
allows a longer length of ETT to be
placed into the larynx before wire/
guide catheter removal.
● Distorted or unrecognizable neck landmarks

Contraindications ● Bleeding diathesis (relative)
● Severe hypoxia, or inability to ventilate (due to time
● Lack of familiarity with technique required)
● Laryngeal stenosis
DESIGN SERVICES OF

F I GUR E 2 2 -1 3 The guide

catheter can be removed after the
ETT is advanced to the CTM, and
then advanced down the tube,
alongside the wire, and into the
trachea. This helps to ensure that
the ETT, when further advanced
after removal of the wire, slides
further down into the trachea and
is not dislodged.
Complications ● Wire may pass distally into trachea, rather than into mouth
● Oral or nasal trauma from wire or passage of ETT
● Folding of tracheal tube inside airway
● Sore throat or hoarseness
● ETT may be inadvertently removed from larynx when
● Trauma to larynx from introduction of needle or wire
wire and guide catheter are removed, resulting in mis-
● Bleeding/hematoma/infection
placed tube
● Inadvertent puncture of esophagus (or wire introduction)
REFERENCES 8. Benumof JL. Management of the difficult airway.

Anesthesiology. 1991;75:1087–1110.
1. McNamara RM. Retrograde intubation of the trachea. Ann 9. Dhara SS. Retrograde tracheal intubation. Anesthesia.
Emerg Med. 1987;16:680–683. 2009;64:1094–1104.
2. Sanchez A, Pallares V. Retrograde intubation technique. In: 10. Hill C, Martel M, Joing S. Retrograde intubation for
Benumof JL, ed. Airway Management. St Louis, MO: Mosby; ACE-inhibitor induced angioedema. Acad Emerg Med.
1996:712–713. 2008;15:791.
3. Hines MH, Meredith JW. Modified retrograde intubation 11. Lleu JC, Forrier M, Pottecher T. Retrograde intuba-
technique for rapid airway access. Am J Surg. 1990;159: tion using the subcricoid region (letter). Br J Anaesth.
597–599. 1983;55:855.
4. Butler FS, Cirillo AA. Retrograde endotracheal intubation. 12. Bourke D, Levesque PR. Modification of retrograde guide
Anesth Analg. 1960;39(4):333–338. for endotracheal intubation. Anesth Analg. 1974;53:
5. Barriot P, Riou B. Retrograde technique for tracheal intuba- 1013–1015.
tion in trauma patients. Crit Care Med. 1988;16:712–713. 13. Lenfant F, Benkhadra M, Trouilloud P, et al. Comparison
6. Weksler N, Klein M, Weksler D, et al. Retrograde tracheal of two techniques for retrograde intubation in human fresh
intubation: beyond fiberoptic endotracheal intubation. Acta cadavers. Anesthesiology. 2006;104:48–51.
Aneasthesiol Scand. 2004:48;412–416. 14. Cooper CM, Murray-Wilson A. Retrograde intubation:
7. Yealy D, Paris PM. Recent advances in airway management. management of a 4.8 kg, 5-month-old infant. Anesthesia.
Emerg Med Clin North Am. 1989;7:83–93. 1988;42:1197–1199.
DESIGN SERVICES OF

PART
Fiberoptic Techniques
VII
CHAPTER
Flexible Fiberoptic
Bronchoscope Intubation
23 cn
Katherin A. Peperzak and Manuel C. Vallejo
Concept the most difficult anatomy and immediate confirmation

of ETT placement.5 It can be performed on all age groups
through a nasal or oral approach.
Fiberoptic bronchoscopes (FOBs) serve many purposes,
Providing adequate anesthesia to the airway is the
both diagnostic and therapeutic. Relatively unchanged
key to intubating with the FOB in the awake patient.
since their development by Shigeto Ikeda in 1966, FOBs
For the nasal approach, anesthesia can be applied topi-
are available in various sizes for different uses and are usu-
cally by coating the nasopharyngeal airways with 2% to
ally 55 or 60 cm in length.1 Instruments used solely for
4% lidocaine paste or gel (3 mL). To minimize risk of
intubation tend to be smaller in diameter (1.8 to 4.0 mm)
epistaxis this may be combined with topical vasocon-
than those used for diagnosis and therapy of pulmonary
strictor solution, such as 0.5% phenylephrine or 0.05%
disease, which facilitate passage of biopsy forceps and other
oxymetazoline (1 mL). Cotton-tipped applicators can be
instruments through a larger working channel. The FOB
soaked in local anesthetic solution and placed in the na-
consists of a light source, an insertion cord, and a handle.
res, to accomplish the same ends. The glottis should be
Generally, light is transmitted to the handle of the scope
anesthetized as well, to allow the ETT to be advanced out
by fiberoptic bundles in a “universal cord” connected to
of the nasopharynx without causing patient discomfort
an external medical-grade endoscopic light source. The
or coughing. For either the nasal or oral approach, this
light is then transmitted from the handle to the end of the
should be accomplished with transtracheal injection of
scope by another set of fiberoptic bundles routed through
2 to 3 mL of 2% lidocaine solution through the cricothy-
the insertion cord. Also along the length of the insertion
roid membrane, or by spraying the same solution through
cord are control wires, which provide for flexion and ex-
the suction channel of the FOB as the cords are visual-
tension of the tip of the scope; a hollow working channel
ized. In addition, topical anesthesia to the larynx and tra-
that allows for suction, administration of local anesthetic
chea may be accomplished with a nebulized solution of
or lavaging fluid, passage of instruments, or insufflation
2% lidocaine (2 to 5 mL).
of oxygen; and an image transmission bundle, which is
For the oral approach, anesthesia in the oral cavity
protected by a lens at its distal end. The handle of the
can be achieved with a combination of superior laryngeal
FOB contains an eyepiece, a diopter adjustment ring,
nerve blocks and topical local anesthetic sprays, gargles,
a control lever connected to the previously mentioned
or paste (see chapter 8). Blocking the superior laryngeal
control wires, a suction button, and an access port to
nerve (branch of CN X), either transcutaneously above the
the working channel. Many FOBs have integrated
thyroid cartilage or transmucosally with Krause forceps,
cameras that allow for real-time video display on an
provides anesthesia to the glottis above the vocal cords,
external monitor. Alternatively, a camera may be attached
as well as the laryngeal surface of the epiglottis. The lin-
to the eyepiece.
gual surface of the epiglottis, the oropharyngeal walls, and
Intubation using a FOB may be performed on an
the posterior tongue can be anesthetized with local anes-
awake or asleep patient, though in patients with an an-
thetic sprays (such as benzocaine or nebulized lidocaine),
ticipated difficult airway it is generally accepted that
pastes, or gels (usually 4% or 5% lidocaine). A transmu-
maintaining consciousness and a protected airway until
cosal injection of 1 to 2 mL of 2% lidocaine at the base of
the airway is secured increases the safety of anesthesia.2–4
the anterior tonsillar pillar blocks the lingual branch of the
Like an optical stylet, the FOB allows the user to move
trigeminal nerve (CN V3), anesthetizing the anterior two-
his or her vantage point into the airway, guiding the tip
thirds of the tongue. An injection of a similar dose of lido-
of the instrument to the trachea, then threading the en-
caine in the gutter between the tongue and the gingivae, at
dotracheal tube (ETT) over it into the airway. The tech-
the base of the palatoglossal arch, anesthetizes the lingual
nique allows for enhanced maneuverability around even
177

178 PART VII ■ FIBEROPTIC TECHNIQUES
branch of the glossopharyngeal nerve (CN IX), suppress- adaptations to fiberoptic intubation include the use of
ing the gag reflex. With all of these methods of providing guidewires through the working channel of the FOB and
topical anesthesia, the cumulative dose of local anesthetic “fibercapnic intubation,” which uses CO2 measurements
should be quantified, and toxic doses (eg, >5 mg/kg of to confirm placement.18 The simultaneous use of direct
lidocaine) must be avoided, as absorption from these vas- laryngoscopy with FOB may improve the success rate of
cular sites can occur rapidly. the technique by displacing soft tissues that can impede
the fiberscopic view of the glottis.19
It is important to note that even during a straight-
Evidence forward awake intubation, the operator performing the
procedure may meet resistance while advancing the ETT
Numerous studies and case series attest to the utility of over the FOB, thus failing tracheal intubation on the first
the FOB in the management of the routine and espe- attempt. Video data from a study by Johnson et al20 reveal
cially the difficult airway.6–10 The American Society of the ETT tube to be most commonly obstructed by the right
Anesthesiologists difficult airway algorithm includes arytenoid (42% of all patients undergoing awake intuba-
a section on awake intubation as well as pathways call- tion) or the interarytenoid soft tissues (11%). Rotating
ing for “Alternative Approaches to Intubation,” which the ETT 90° counterclockwise such that the bevel faces
includes use of fiberoptic scopes.11 Although there is no posteriorly often results in successful passage of the tube
advocated “best” device for use in these situations, use of on subsequent attempts. The authors suggest orienting the
the FOB is probably the oldest and best-described tech- ETT in this position, and positioning the FOB in the cen-
nique.12 Surveys of anesthesiologists in the United States ter of the arytenoids on the initial attempt may increase
indicate that the FOB is the preferred intubation device in the success rate and therefore reduce potential laryngeal
the management of the difficult airway.13 Further, fiber- injury.
optic intubation is associated with greater hemodynamic Ultra-thin fiberscopes with outer diameters as small as
stability and less morbidity compared with direct laryngo- 2.5 mm are available for the pediatric and neonate popula-
sopy.14 In unanticipated difficult airways, intubation over tion.1,21 Fiberoptic intubation has been successfully applied
the bronchoscope can be successfully performed through in various pediatric difficult airway situations, such as con-
a laryngeal mask airway (LMA) and around the esopha- genital anomalies including microagnathia,22 trauma,23 and
geal tracheal Combitube.3,4,15 airway obstruction due to edema.24 Although a multitude
The utility of FOB for intubation of patients with sus- of difficult fiberoptic-compatible oral airways is available
pected or confirmed cervical spine injuries where move- for adults,1,25 the LMA is the most commonly used device
ment can further damage (transect) the spinal cord is well to facilitate introduction of the bronchoscope in pediat-
established. It can be performed without any movement of rics and may be used with or without an airway exchange
the cervical vertebrae and allows for evaluation of neuro- catheter and/or guidewire.21 As is readily evident, there are
logic function in awake patients throughout and after the many advantages to the FOB technique, including applica-
procedure.4,7,9 Intraoperatively, the FOB has proven to be bility to all age groups, excellent airway visualization, abil-
useful during a case of accidental tracheal extubation in ity to insufflate oxygen during the procedure, high success
a patient in the prone position with her neck flexed and rate, and immediate confirmation of ETT placement.9
pinned in a Mayfield head holder for craniotomy. Use of
an LMA or mask ventilation was limited due to the pa-
tient’s extreme positioning, but the airway was success-
fully rescued via fiberoptic intubation.16 Preparation (Figs. 23-1–23-9)
The FOB is also beneficial for patients with known
trauma to the airway because it allows placement of the ● Set up for direct laryngoscopy (see Chapter 5)
ETT beyond the level of the injury and therefore reduces ● Inject antisialagogue (0.2 to 0.4 mg glycopyrrolate)
the risk of creating a false passage.4 Furthermore, the FOB 15 to 20 minutes prior to anticipated procedure
is particularly useful in cases of lingual tonsillar hyper- ● For awake procedure, topicalize or block nerves of
plasia, a common cause of airway obstruction and dif- pharynx and oral cavity (or nasal cavity, if it is to be a
ficult intubation. Ideally, these patients should undergo nasotracheal procedure)
awake intubation, but in cases of unanticipated lingual ● If nasotracheal approach is planned, coat nasopharyn-
tonsillar hyperplasia, a technique successfully using the geal airway with topical vasoconstrictor solution, such as
FOB through the bronchial lumen of a double-lumen ETT 0.5% phenylephrine or 0.05% oxymetazoline
and a rigid stylet through the tracheal lumen has been ● For awake procedure, topicalize larynx with nebulized
described.17 In patients with particularly distorted anat- lidocaine, lidocaine spray from scope tip, or transtracheal
omy or severe airway obstruction, other potentially useful injection of 2% lidocaine (2 to 3 mL)

CHAPTER 23 ■ FLEXIBLE FIBEROPTIC BRONCHOSCOPE INTUBATION 179
FIG U RE 23-1 Typical fiberoptic intubating

scope: note insertion cord, universal cord, and
handle.
Universal
Insertion cord cord
Diopter
adjustment
Handle ring Eyepiece
Suction button
FIG U RE 23-2 Equipment for oral fiberoptic

awake intubation.
FIG U RE 23-3 Equipment for nasal fiberoptic

awake intubation.

F I GUR E 2 3 -4 Commercially available atomizers

allow a fine spray to be directed to the pharynx or
back of the tongue.
F I GUR E 2 3 -5 Transmucosal injection of

local anesthetic in the “gutter” between
the posteriormost molar and the tongue
provides anesthesia to lingual branches of the
glossopharyngeal nerve (CN IX). Needle insertion
should be limited to 0.5 to 1 cm of depth, with
careful aspiration to avoid intravascular injection.
F I GUR E 2 3 -6 Transmucosal approach for

superior laryngeal nerve block (CN X). Krause
forceps with a lidocaine-soaked pleget are placed in
pyriform recesses on each side.

FIG U RE 23-7 Transcutaneous approach for

superior laryngeal nerve block (CN X). A 22G
to 25G needle is inserted just medial and cephalad
to the greater horn of the thyroid cartilage on each
side.
FIG U RE 23-8 Lidocaine nebulization for

laryngeal and tracheal anesthesia.
FIG U RE 23-9 Anesthestizing the glottis by trans-

tracheal lidocaine injection through the cricothyroid
membrane. If desired, a 20G intravenous catheter
can be used for this purpose to prevent injury to the
airway by a needle in the event the patient coughs
during injection. Anesthesia may also be achieved
by administering lidocaine through the suction
channel of the FOB as the cords are visualized.

F I GUR E 2 3 -1 0 Williams airway inserted for

FOB intubation in anesthetized patient.
● Lubricate FOB ● Identify cords, advance scope between them

● Load ETT on FOB ● Advance scope tip until carina is in sight
● Administer mild sedation but preserve cooperation and ● Stabilize FOB and advance ETT (or have the assistant
airway reflexes do this)
● Patient may be supine or, if intubation is to be carried out ● If resistance occurs, ETT bevel may be hung up on aryte-
awake, may also be seated or semirecumbent noid cartilage or aryepiglottic fold: withdraw ETT slightly
● Check light source and image, focus if necessary and turn 90° counterclockwise, then attempt to advance
● Coat end of scope with antifogging solution gently
● Preoxygenate patient ● After tube passes into airway, remove FOB while visual-
● Stand at the head of the patient (it is also possible to stand izing tracheal rings and ETT in airway on withdrawal
in front of the semirecumbent patient, if awake intubation ● Confirm placement of ETT with detection of CO2 and
is performed) auscultation after scope is removed
Practicality
Procedure (for Orotracheal FOB
Intubation) (Figs. 23-10–23-20) ● Unfamiliar and complex: requires considerable practice
● Very expensive: scope, cart, and light source run to more
● Place oral Williams, Bermann, or Ovassapian airway, or than $5,000
have assistant use laryngoscope to elevate and compress ● Awkward, multiple components, not easily portable
tongue; a simple jaw thrust may also suffice ● Battery-operated FOB reduces complexity and improves
● A mask with diaphragm (such as a Patil-Syracuse portability
mask), or anesthesia circuit with adaptor for FOB can ● Time-consuming: with patient preparation, awake FOB
be used with oral airway to maintain ventilation during intubation may require more than 20 minutes
FOB ● Requires logistic support for cleaning, maintenance
● Pass FOB through oral airway, mask, or bronchoscopy ● Most FOBs have a finite number of uses due to routine
adaptor wear and tear requiring expensive maintenance, repairs,
● Maintain scope tip in midline or replacement
● Guide scope forward, curving the tip toward the glottis:
upward and downward pressure applied with the thumb
on the tip control lever curves the tip Indications
● Turn handle and scope tip as a unit; avoid twisting the
insertion cord, which can break fibers ● Predicted difficult intubation
● Visualize glottis through scope ● Immobile cervical spine (halo, collar, in-line
● Spray vocal cords with 1% lidocaine (2 mL) unless already immobilization)
topicalized with transtracheal injection or nebulization ● Difficult laryngoscopy with preserved mask ventilation

FIG U RE 23-11 Insertion of FOB for oral

intubation, from top of patient.
FIG U RE 23-12 Insertion of FOB for oral

intubation, from front of an awake, semirecumbent
patient.
FIG U RE 23-13 Jaw thrust during oral FOB

insertion permits visualization of the glottis.

F I GU R E 2 3 -1 4 Oral ETT insertion over FOB.
F I GUR E 2 3 -1 5 Oral FOB

approach: insertion of ETT and FOB
in cadaver specimen.

FIG U RE 23-16 Epiglottis as seen through FOB

during oral approach.
FIG U RE 23-17 Poor view of glottis as seen

through FOB during oral approach: epiglottis seen
lying against posterior pharyngeal wall, obscuring
view of glottis (jaw thrust dramatically improved the
view, as seen in Figure 23-18).
FIG U RE 23-18 Improved view of glottis, as seen

through FOB after jaw thrust.

F I GUR E 2 3 -1 9 After entering larynx, tracheal

rings are apparent, as seen through FOB.
F I GUR E 2 3 -2 0 Carina, as seen through FOB.
Contraindications ● Larynx should be in view

● Advance tip of scope to glottis
● Spray cords with 1% lidocaine ([2 mL], unless already
● Emergent intubation (due to time requirements)
topicalized)
● Uncooperative patient (will not permit awake procedure)
● Advance tip of scope through glottic opening, confirm by
● Copious blood and secretions in airway
noting tracheal rings
● Inaccessibility of oral cavity
● Continue to advance tip of scope until carina is visualized
● Stabilize scope and advance ETT over scope into nose
● Proceed with ETT insertion, through glottic opening
● Alternatively, place ETT through nose to level of naso-
Procedure (for Nasal FOB pharynx, then insert FOB, advancing into airway, fol-
Intubation) (Figs. 23-21–23-24) lowed by introduction of ETT
● If ETT “hangs up” at larynx (Fig. 23-25), avoid force, and
● Insert FOB into anesthetized, prepared nare pull back ETT slightly, rotating it counterclockwise 90°,
● Advance along floor of nose then readvance gently
● Visualize nasopharynx, curve tip of scope down toward ● Confirm ETT is in airway as scope is withdrawn
glottis ● Reconfirm ETT position with usual means

FIG U RE 23-21 Nasal approach for FOB

intubation, in awake, seated patient.
FIG U RE 23-22 Insertion of FOB through

nasal cavity in cadaver specimen.

F I G U R E 2 3 -2 3 ETT advancement into

nasopharynx over FOB.
Indications Complications of Oral

and Nasal FOB Intubation
● Cervical spine injury or immobility ● Inability to visualize airway (due to secretions, fogging, or
● Predicted difficult intubation tip of scope deviating laterally)
● Misplacement of ETT
● Trauma to larynx from insertion of ETT over the scope
Contraindications ● Patient intolerance of awake procedure, usually due to
insufficient topicalization of mucosa
● Emergent intubation (due to time required) ● Inability to pass ETT (occurs in up to 10% of cases),
● Coagulopathy or anticoagulation (due to risk of requiring smaller ETT to be used
epistaxis) ● Mainstem bronchus intubation
● Uncooperative patient ● Patient hypoxia due to prolonged attempts, or failure to
● Copious blood or secretions in airway ventilate during attempts at intubation
● Head or facial tumor ● Epistaxis (from nasal approach)

FIG U RE 23-24 ETT placed over FOB into larynx.
FIG U RE 23-25 Bevel of ETT “caught” on

aryepiglottic fold during tube insertion, preventing
intubation of trachea. Pulling the ETT back a few
centimeters, rotating it 90° counterclockwise, and
readvancing usually solves this problem.

REFERENCES 14. Cook JR. Using the literature to quantify the learning curve:
a case study. Int J Technol Assess Health Care. 2007;23:
1. Gil KS. Fiber-optic intubation: tips from the ASA workshop. 255–260.
Anesthesiology News. 2009;35:91–98. 15. Ovassapian A. Fiberoptic tracheal intubation with the
2. Hagberg CA. Current concepts in the management of the esophageal-tracheal Combitube in place. Anesth Analg.
difficult airway. Anesthesiology News. 2010;36:1–23. 1993;75:S385.
3. Koerner IP, Brambrink AM. Fiberoptic techniques. Best 16. Hung MH, Fan SZ, Lin CP, et al. Emergency airway manage-
Pract Res Clin Anaesthesiol. 2005;19:611–621. ment with fiberoptic intubation in the prone position with a
4. Stackhouse RA. Fiberoptic airway management. Anesthesiol flexed neck. Anesth Analg. 2008;107:1704–1706.
Clin North Am. 2002;20:933–951. 17. Orhan ME, Gözübüyük A, Sizlan A, et al. Unexpected diffi-
5. Popat M. State of the art: the airway. Anaesthesia. cult intubation due to lingual hyperplasia in a thoracotomy
2003;58:1166–1171. patient. J Clin Anesth. 2009;21:439–441.
6. Ovassapian A, Doka JC, Romsa DE. Acromegaly. Use 18. Huitnik JM, Balm AJ, Keijzer C, et al. Awake fibrecapnic
of a fiberoptic laryngoscope to avoid tracheostomy. intubation in head and neck cancer patients with difficult
Anesthesiology. 1981;54:429–430. airways: new finding and refinements to the technique.
7. Edens ET, Sia RL. Flexible fiberoptic endoscopy in difficult Anaesthesia. 2007;62:214–219.
intubations. Ann Otol Rhinol Laryngol. 1981;90:307–309. 19. Russell SH, Hirsch NP. Simultaneous use of two laryngo-
8. Ovassapian A, Yelian SJ, Dykes HM, et al. Fiberoptic naso- scopes. Anaesthesia. 1993;48:918.
tracheal intubation. Anesth Analg. 1983;62:692–695. 20. Johnson DM, From AM, Smith RB, et al. Endoscopic study
9. Ovassapian A, Schreaker SC. Fiberoptic-aided bronchial in- of mechanisms of failure of ETT advancement into the
tubation. Semin Anesth. 1987;6:133–145. trachea during awake fiberoptic orotracheal intubation.
10. Elizondo E. Endotracheal intubation with flexible fiberoptic Anesthesiology. 2005;102:910–914.
bronchoscopy in patients with abnormal anatomic conditions 21. Walker RW, Ellwood J. The management of difficult intuba-
of the head and neck. Ear Nose Throat J. 2007;86:682–684. tion in children. Paediatr Anaesth. 2009;19:77–87.
11. American Society of Anesthesiologist Task Force on 22. Finer NN, Muzyka D. Flexible endoscopic intubation of the
Management of the Difficult Airway. Practice guidelines neonate. Pediatr Pulmonol. 1992;12:48–51.
for management of the difficult airway. An updated report 23. Rucker RW, Lilva WJ, Worcester CC. Fiberoptic bron-
by the American Society of Anesthesiologist Task Force choscopic nasotracheal intubation in children. Chest.
on Management of the Difficult Airway. Anesthesiology. 1979;76:56–62.
2003;98:1269–1277. 24. Baines DB, Goodrick MA, Beckenham EJ, et al. Fiberoptically
12. Berkow LC. Strategies for airway management. Best Pract guided endotracheal intubation in a child. Anaesth Intens
Res Clin Anaesthesiol. 2004;18:531–548. Care. 1989;17:354–355.
13. Ezri T, Szmuk P, Warters RD, et al. Difficult airway man- 25. Atlas GM. A comparison of fiberoptic-compatible oral air-
agement practice patterns among anesthesiologists practic- ways. J Clin Anesth. 2004;16:66–73.
ing in the United States: have we made any progress. J Clin
Anesth. 2003;15:418–422.

CHAPTER
Rigid Fiberoptic Scopes and

Video Laryngoscopes
24 cn
Joshua S. Baisden and Michael Mangione
Concept the uvula, the GVL blade is inserted in the vallecula or

alternatively passed beyond the epiglottis if the epiglottis
Similar to their flexible counterparts, rigid fiberoptic obstructs viewing the glottis.3 With the glottis in view on
scopes are devices that permit indirect observation of the monitor, the ETT is then passed into the airway with
the glottis and allow the operator to visualize passage of visual confirmation of ETT placement. Achieving an ad-
the endotracheal tube (ETT) into the airway. Newer de- equate view of the glottis with the GVL appears routine,
vices, called videolaryngosopes, resemble conventional although placement of the ETT can remain difficult due to
laryngoscopes but allow visualization of the airway on a the curvature of the GVL blade; thus, use of a rigid sylet is
video screen mounted nearby or attached to the handle recommended during ETT placement.3,4
of the device. Currently, the most commonly used of One of the newest additions to the rigid fiberop-
these devices is the GlideScope videolaryngoscope or GVL tic scope collection is the Pentax AWS. This innova-
(Verathon Inc., Bothell, WA, USA; Figs. 24-1 and 24-2). tive device consists of a 2.4⬙ LCD full color monitor, a
Other promising videolaryngoscopes are the Pentax 12-cm cable with a charge-coupled device camera, and
AWS (Hoya Corp., Tokyo, Japan; Figs. 24-3 and 24-4) a disposable clear blade (PBlade, Hoya Corp., Tokyo,
and the C-MAC Storz (Karl Storz, Tuttlingen, Germany; Japan). The disposable PBlade is placed over the image
Fig. 24-5). Older, but well-described devices include the cable leaving the camera approximately 3 cm from the
Bullard laryngoscope (Gyrus ACMI, Southborough, MA, tip of the blade. The PBlade allows an ETT to be attached
USA; Fig. 24-6), the Upsherscope (Mercury Medical, to the right side of the blade to facilitate ETT placement
Clearwater, FL, USA; Fig. 24-7), and the WuScope (Achi (compatible with ETT sized 6.5 to 8.0). The PBlade also
Corp. San Jose, CA, USA; Fig. 24-8). Rigid fiberoptic houses a port through which a suction catheter can be
scopes are inserted into the hypopharynx to obtain a view passed. The entire device is powered by two AA alka-
of the glottis rather than into the airway like flexible fi- line batteries that allows continuous operation for up to
beroptic scopes. The ETT is then inserted into the airway 1 hour. Insertion of the Pentax AWS is similar to the in-
while visualizing its progress with the scope. Some types sertion of a Miller blade, with the distal end of the blade
have a stylet onto which the ETT is loaded, whereas others placed on the glottic side of the epiglottis. There is a
require freehand insertion. sighting device on the LCD monitor that allows the user
Rigid fiberoptic scopes may be used routinely in air- to align the tip of the ETT with the glottic opening to as-
way management, but they have proven to be very useful sist with ease of intubation.5,6
in placement of the ETT when there is difficulty in aligning The original model for the rigid fiberoptic scope is
the oral, pharyngeal, and laryngeal axes, such as in patients the Bullard laryngoscope. This device features a blade
with cervical spine immobilization or atlanto-occipital contour designed to match the anatomy of the upper air-
joint disease.1,2 Rigid videolaryngoscopes have also proven way. The blade then mounts onto a standard laryngoscope
to be invaluable as a teaching tool. These devices allow the handle. The Bullard laryngoscope encompasses a fiberop-
apprentice to visualize airway anatomy such as the epiglottic bundle that lies on the posterior aspect of the blade
tis and glottis by looking at the video screen. The teacher and is located near the end of the blade. It also possesses
is able to look at the video screen and help to guide the a working channel that runs the entire length of the blade
process of intubation using real-time visualization. for introduction of medications, suction, or oxygen in-
The GVL is a commonly used and well-studied rigid sufflation. Intubation with the Bullard is achieved by the
scope. This device features a blade similar to a Macintosh operator inserting the scope in a midline pathway into
blade, but the GVL blade is made of durable plastic and the hypopharynx in an anesthetized patient. The operator
has a more acute distal curvature (60°). There is an ac- then advances the blade into position cephalad to the glot-
companying video camera at the distal end of the blade tis. This yields an excellent view of the larynx. The ETT
that serves to project an image of the glottis on a liquid can then be pushed forward off the stylet (or placed free-
crystal display (LCD) monitor.3 Insertion of the GVL clas- hand), into the glottis, while observing placement through
sically follows a midline approach. After visualization of the instrument.
191

F I GUR E 2 4 -1 The GVL featuring Mac 3, Mac 4, Mac 5 blades and

rigid stylette.
(Courtesy of Verathon Inc., Bothell, WA, USA.)
F I GUR E 2 4 -2 View of glottis with the GVL.

(Courtesy of Verathon Inc., Bothell, WA, USA.)
DESIGN SERVICES OF

CHAPTER 24 ■ RIGID FIBEROPTIC SCOPES 193
FIG U RE 24-3 Pentax AWS with ETT.

(Courtesy of Ambu Corp., Ølstykke, Denmark.)
FIG U RE 24-4 Pentax AWS and disposable

clear blade.
(Courtesy of Ambu Corp., Ølstykke, Denmark.)
DESIGN SERVICES OF

F IG U R E 2 4 -5 The Storz C-MAC

and conventional MAC blade.
F I GU R E 2 4 -6 The Bullard laryngoscope.
DESIGN SERVICES OF

FIG U RE 24-7 The Upsherscope.

(Courtesy of Mercury Medical, Clearwater, FL,
USA.)
FIG U RE 24-8 The WuScope.

(Courtesy of Achi Medical Products,
San Jose, CA, USA.)
DESIGN SERVICES OF

Evidence in-line cervical immobilization, intubation was signifi-

cantly easier to accomplish and required less time with the
rigid apparatus. The Bullard scope has proven useful for
The GlideScope has been extensively evaluated since its in-
management of normal and difficult pediatric airways.17
troduction to clinical practice in late 2001. Numerous stud-
The Upsherscope, a rigid scope incorporating a
ies have compared the laryngeal view obtained by the GVL
C-shaped steel blade with the enclosed fiberoptic bundles
and direct laryngoscopy (DL). In their 2005 study, Cooper
and an intubation channel, proved to have no advantage
et al3 show that the GVL was able to produce a Cormack-
over DL in enabling intubation in a group of 300 patients
Lehane (C/L) grade 1 or 2 view in 99% of patients enrolled
randomly assigned to airway management in the operating
in the study. The same study also shows that in 133 patients
room by either technique.18 In fact, the authors reported
who underwent both GVL and DL, the C/L grade 1 views
a 15% failure rate with the Upsherscope, compared with
were 85.7% versus 48.9%, respectively.3 Several other stud-
3% with DL.18
ies support an improved C/L grade when comparing the
New literature regarding the clinical utility of the
GVL with the conventional DL.7–9 The GVL has also been
GlideScope and other videolaryngoscope devices has con-
shown to improve the rate of successful tracheal intuba-
tinued to emerge. A recent study from Aziz et al19 provided
tion when compared with the DL.8,10,11 Malik’s8 2009 study
a retrospective chart review of all intubations occurring
shows a 96% intubation success rate with the GVL com-
at two academic institutions over a 2-year period, 2,004
pared with the 84% success of DL. Inexperienced opera-
of which were GVL intubations. The researchers found
tors may benefit more from using the GVL compared with
an overall GVL success rate of 97% in all situations.19
conventional DL.10 Another commonly studied variable is
They also reported a 96% success rate (1,377 of 1,428)
time to intubation in the GVL compared with DL. Review
in patients with predictors of difficult DL.19 Possibly, the
of current literature does not give a consistent answer as to
most important statistic from this article was a 94% suc-
the efficiency of the GVL when compared with DL.
cess rate (224 of 239) of GVL intubation following failed
The Pentax AWS and C-MAC Storz have been exten-
DL.19 Predictors of failure with the GVL were masses in the
sively studied recently. Numerous studies support an im-
neck, or prior surgery or radiation in this region. Currently,
proved C/L grade with the Pentax AWS compared with
the GlideScope and other rigid videolaryngoscopes are not
DL.5,8,12,13 A recent study by Asai and colleagues5 shows
found in the American Society of Anesthesiologists dif-
a 99.3% tracheal intubation success rate with the Pentax
ficult airway algorithm, though this study and others that
AWS in patients where DL with a Macintosh laryngo-
attest to the utility of these devices raise the question of
scope was difficult or failed. This device also appears to
whether or not they should be included in future versions
improve the C/L grade and success rate of tracheal intuba-
of difficult airway management recommendations.
tion compared with DL in patients with restricted neck
movement.12,13 More studies need to be performed to see
if there is a significant decrease in time to intubation us- Preparation for Use of the GVL
ing the Pentax AWS compared with conventional DL. The
(Fig. 24-1):
V-MAC Storz DCI has also been shown to improve the C/L
grade when compared with conventional DL.9 Maassen
and colleagues9 were able to show that use of the V-MAC ● Prepare for DL (refer to chapter 5)
Storz DCI required fewer attempts to secure the airway ● Select the appropriate size of GVL Blade (Fig. 24-1)
and decreased time to intubation when compared with the ● Direct the tip of the blade toward a recognizable target and
GlideScope and McGrath videolaryngoscope. ensure appropriate image clarity and orientation on screen
The Bullard has also been extensively evaluated. This ● Place the pre-formed GVL stylet through the ETT
device appears to be safe and effective for airway manage-
ment in the patient with a potential cervical spine injury.14
Watts15 compared the time required for intubation and the
Procedure for Use of the GVL
degree of cervical extension using the Bullard scope versus (Fig. 24-2):
that for DL, both with and without in-line cervical immobi-
lization, in patients under general anesthesia. The degree of ● Place the GVL blade in the midline of the patients mouth
spine extension and the time to intubate were similar, ex- ● Advance the blade tip into the hypopharynx while watch-
cept when cervical immobilization was imposed, at which ing the screen
time the average duration required for intubation with the ● Obtain an optimal image of the glottis (Fig. 24-2)
Bullard scope was significantly prolonged, ranging from ● Place the ETT through the glottic opening under direct
25 to 40 seconds.15 However, Schulman16 reported in a visualization using the GVL screen
randomized trial in 50 patients under anesthesia that, in
comparing the Bullard scope to a flexible fiberscope during Remove the blade and confirm ETT position in the airway
DESIGN SERVICES OF

Table 24-1
Rigid Fiberoptic Scope Overview
Cost Portability Channeling Disposable Complexity

GlideScope $10,000 No No No Easy to learn to use
Pentax AWS $9,000 Yes Yes Blade Some learning curve
C-MAC Storz $15,000–$20,000 Yes No No Similar to DL
Bullard $2,000–$3,000 No Yes No Steep learning curve
RIGID FIBEROPTIC SCOPE Contraindications

GENERALIZATIONS
● Copious blood or secretions in airway
Practicality ● Inaccessibility of oral cavity (the patient must be able to
open atleast 2 cm)
● Improved success rate for tracheal intubation compared ● Uncooperative patient
with DL, especially in patients limited neck range of mo- ● Inability to ventilate, or hypoxemia (due to time required
tion or presumed difficult airway; improved C/L grade to perform these interventions)
compared with DL ● Upper airway obstruction
● Pharyngeal or laryngeal trauma
Complexity
Complications
● Less so than fiberoptic bronchoscope and similar to con-
ventional DL ● Pharyngeal or dental trauma from scope placement
● Laryngeal trauma from ETT insertion or rigid stylet
Affordibility ● ETT misplacement
● Prolonged intubation attempts with hypoxia
● Relatively expensive with devices ranging from $2,000 to
$20,000 (Table 24-1)
Indications
● Predicted difficult intubation

● Patient with potential cervical spine injury requiring air-
way management
● Poor laryngoscope grade during DL
REFERENCES and Technology, Virtual Anesthesia Machine Web site:

http://vam.anest.ufl.edu/airwaydevice/bullard/index.html
1. Barash PG, Cullen BF, Stoelting RK, et al, eds. Clinical 3. Cooper RM, Pacey JA, Bishop MJ, et al. Early clinical expe-
Anesthesia. 6th ed. Philadelphia, PA: Lippincott Williams & rience with a new video laryngoscope (GlideScope) in 728
Wilkins; 2009. patients. Can J Anesth. 2005;52:191–198.
2. Liem EB. Bullard Laryngoscope Intubation.2006. Retrieved 4. Kramer DC, Osborn IP. More maneuvers to facilitate tra-
July 3, 2010, from University of Florida Department of cheal intubation with the GlideScope. Can J Anaesth.
Anesthesiology, Center for Simulation, Advanced Learning 2006;53:737.
DESIGN SERVICES OF

5. Asai T, Liu EH, Matsumoto S, et al. Use of the Pentax- a comparison of the Airwayscope, LMACTrach, and the
AWS in 293 patients with difficult airways. Anesthesiology. Macintosh laryngoscopes. Br J Anaesth. 2009;102:654–661.
2009;110:898–904. 13. Enomoto Y, Asai T, Arai T, et al. Pentax-AWS, a new
6. Asai T, Enomoto Y, Shimizu K, et al. The Pentax-AWS videolaryngoscope, is more effective than the Macintosh
video-laryngoscope: the first experience in one hundred laryngoscope for tracheal intubation in patients with re-
patients. Anesth Analg. 2008;106:257–259. stricted neck movements: a randomized comparative study.
7. Bathory I, Frascarolo P, Kern C, et al. Evaluation of the Br J Anaesth. 2008;100:544–548.
GlideScope for tracheal intubation in patients with cervi- 14. Hastings RH, Vigil AC, Hanna R, et al. Cervical spine move-
cal spine immobilisation by a semi-rigid collar. Anaesthesia. ment during laryngoscopy with the Bullard, Macintosh, and
2009;64:1337–1341. Miller laryngoscopes. Anesthesiology. 1995;82:859–869.
8. Malik MA, Subramaniam R, Maharaj CH, et al. Randomized 15. Watts AD, Gelb AW, Bach DB, et al. Comparison of the
controlled trial of the Pentax AWS, GlideScope, and Bullard and Macintosh laryngoscopes for endotracheal in-
Macintosh laryngoscopes in predicted difficult intubation. tubation of patients with potential cervical spine injury.
Br J Anaesth. 2009;103:761–768. Anesthesiology. 1997;87:1335–1342.
9. Maassen R, Lee R, Hermans B, et al. A comparison of three 16. Schulman GB, Connelly NR. A comparison of the Bullard
videolaryngoscopes: the Macintosh laryngoscope blade re- laryngoscope versus the flexible fiberoptic bronchoscope
duces, but does not replace, routine stylet use for intubation during intubation in patients afforded in-line stabilization.
in morbidly obese patients. Anesth Analg. 2009;109:1560– J Clin Anesth. 2001;13:182–185.
1565. 17. Borland LM, Casselbrant M. The Bullard laryngoscope: a
10. Nouruzi-Sedeh P, Schumann M, Groeben H. Laryngoscopy new indirect oral laryngoscope (pediatric version). Anesth
via Macintosh blade versus GlideScope: success rate and Analg. 1990;70:105–110.
time for endotracheal intubation in untrained medical 18. Fridrich P, Frass M, Krenn CG, et al. The Upsherscope in
personnel. Anesthesiology. 2009;110:32–37. routine and difficult airway management: a randomized,
11. Powell L, Andrzejowski J, Taylor R, et al. Comparison of controlled clinical trial. Anesth Analg. 1997;85:1377–1381.
the performance of four laryngoscopes in a high-fidelity 19. Aziz MF, Healy D, Kheterpal S, et al. Routine clinical
simulator using normal and difficult airway. Br J Anaesth. practice effectiveness of the GlideScope in difficult airway
2009;103:755–760. management: an analysis of 2,004 GlideScope intubations,
12. Malik MA, Subramaniam R, Churasia S, et al. Tracheal complications, and failures from two institutions.
intubation in patients with cervical spine immobilization: Anesthesiology. 2011;114:34–41.
DESIGN SERVICES OF

PART
Emergency Ventilation
VIII
CHAPTER
Esophageal-Tracheal Combitube 25 cn
R. Scott Lang and Derek Davis
Concept that it provides better protection from aspiration with its

double-lumen design. There have been reports of success-
ful use of the ETC in the intensive care setting,4 but case
The Esophageal-Tracheal Combitube (ETC) is a double-
reports of tongue engorgement have suggested that long-
lumen airway device that is used to secure ventilation
term use may increase the risk of airway complications.5
through blind placement into the oropharyngeal cavity.
Ischemia-reperfusion injury or compression of the glos-
This is a supraglottic airway that is most commonly in-
sal blood vessels were suggested as possible causes of this
serted into the esophagus, but can also be blindly inserted
complication. Pressures that are up to three times higher
into the trachea, though this is uncommon and usually
than the mucosal perfusion pressure have been measured
occurs inadvertently (Fig. 25-1). Careful auscultation will
in properly inflated pharyngeal cuffs.6
allow the operator to determine whether the ETC is in the
Force upon insertion of the ETC should be avoided,
esophagus or the trachea. Tracheal insertion allows the
as it may cause esophageal rupture,7 subcutaneous emphy-
operator to use the Combitube as a standard endotracheal
sema, pneumomediastinum, and pneumoperitoneum.8 A
tube. The ETC has two inflatable cuffs to seal the airway
retrospective review of prehospital complications with
and allow ventilation. The proximal cuff (oropharyngeal
ETC insertion reported dental trauma, inability to de-
cuff) is larger in volume and can be inflated with up to
termine placement due to emesis through both lumens,
100 cc of air, depending on the size of the Combitube. The
and dislodgement during transport.1 Though there are
distal cuff is smaller and is inflated in either the esophagus
reported complications, the ETC continues to be used
or the trachea with 10 to 15 cc of air, depending on the
successfully as a blind insertion rescue airway device dur-
size and position of the device. The double-lumen design
ing emergent situations.
allows for ventilation while passing an orogastric tube
through the smaller lumen to decompress the stomach.
The longer of the two lumens, or the blue lumen, has side Preparation (Fig. 25-1)
ports for ventilation within the pharynx and ends blindly.
The ETC comes in a standard size (42 French) and a ● Preparation for direct laryngoscopy (see Chapter 5)
smaller size (37 French) for smaller individuals. ● Check pilot balloons and cuffs of ETC
● Anesthetized or unconscious patient in neutral position
● Preoxygenation is preferred; however, this device is most
Evidence likely to be used when intubation and mask ventilation
are impossible
The ETC has been used successfully as an airway for sev-
eral years by trained and untrained operators for both rou-
tine and emergent airway management. It has been used Procedure (Figs. 25-2–25-6)
for prehospital management,1 for routine airway manage-
ment for operative procedures, and during cardiopulmo- ● Grasp lower teeth of patient with left hand, pulling
nary resuscitation.2 A comparison of the ETC with the upward
laryngeal mask airway (LMA) when used by staff not pre- ● Insert ETC into pharynx and advance until the pair of
viously trained in airway management after induction of black lines on the tube lie on either side of the front up-
anesthesia showed that the ETC can be used successfully per incisors
by untrained personnel.3 The LMA may be a more practi- ● Insufflate air into the blue pilot balloon, cuff 1 (100 mL for
cal device for untrained personnel when considering the 41 French ETC, 85 mL for 37 French ETC), and then into
extra maneuvers for placement of the ETC and its higher the white pilot balloon, cuff 2 (10 to 15 mL for 41 French
cost. The advantage of the ETC in the emergent setting is ETC, 6 to 12 mL for 37 French ETC)
199

200 PART VIII ■ EMERGENCY VENTILATION
F I GUR E 2 5 -1 The ETC. Note two tubes with

two cuffs, two pilot balloons, and two lumens.
Lumen 1 (blue) to pharyngeal

side holes
Lumen 2 (white) to distal
Pharyngeal orifice
ventilation
Distal side holes
orifice
Oropharyngeal cuff
Distal cuff (usually in esophagus)
F I GUR E 2 5 -2 ETC inserted into pharynx in

cadaver specimen.
DESIGN SERVICES OF

CHAPTER 25 ■ ESOPHAGEAL-TRACHEAL COMBITUBE 201
FIG U RE 25-3 ETC advanced into esophagus.
FIG U RE 25-4 Cuffs of ETC inflated. Note

proximity of pharyngeal side holes to glottic
opening, and seal provided by distal and
proximal balloons.
DESIGN SERVICES OF

F I GUR E 2 5 -5 The head is placed in a neutral

position and the mandible is pulled forward by
grasping the lower teeth and chin. The mouth
is opened during this maneuver. The ETC is
then inserted through the pharynx into the
esophagus blindly.
F I GUR E 2 5 -6 The device is gently pushed

down until the black lines on the ETC are
aligned on either side of the incisors.
DESIGN SERVICES OF

CHAPTER 25 ■ ESOPHAGEAL-TRACHEAL COMBITUBE 203
● Ventilate through Lumen 1 (blue), which is the ● Lack of intubation equipment or other airway devices
pharyngeal lumen; gas exits the side holes lying in the ● Securing an airway blindly and decreasing risk of aspiration
hypopharynx
● Check for breath sounds, chest rise, and end-tidal CO2: Contraindications
if these are present, then secure the ETC
● If no ventilation is evident, begin ventilation through ● Esophageal injury or severe disease
Lumen 2 (clear), the distal tip lumen ● Laryngeal or pharyngeal injury
● Check for breath sounds, chest rise, and end-tidal CO2: if ● Supraglottic obstruction (tumor, foreign body)
these are present, the tube is in the trachea and should be ● Spontaneously breathing or alert patient
secured and regarded as an endotracheal tube ● Inability to access the oral cavity (trauma or any other
● If there is no evidence of ventilation through either lumen, conditions)
pull the ETC back slowly after deflating the cuffs, as it is
probably inserted too far, and check repeatedly for evi-
dence of ventilation. When ventilation is evident, secure Complications
the tube at that level.
● Esophageal injury (rupture, laceration)
Practicality ● Subcutaneous emphysema
● Pneumomediastinum
● Pneumoperitoneum
● Portable; affordable relatively easy to use; effective in man- ● Pharyngeal trauma
aging an airway in most emergent situations ● Dental injury
● Improper positioning or dislodgement
Indications
● Inability to mask ventilate
● Inability to secure endotracheal intubation
● Untrained providers or providers with limited airway
management training
REFERENCES 5. McGlinch BP, Martin DP, Volcheck GW, et al. Tongue

engorgement with prolonged use of the esophageal-tracheal
1. Calkins TR, Miller K, Langdorf MI. Success and compli- Combitube. Ann Emerg Med. 2004;44:320–322.
cation rates with prehospital placement of an esophageal- 6. Caplan RA, Benumof JL, Berry FA, et al. Practice guide-
tracheal combitube as a rescue airway. Prehosp Disast Med. lines for management of the difficult airway: a report by
2006;21(2):97–100. the American Society of Anesthesiologists Task force
2. Frass M, Frenzer R, Rauscha F, et al. Ventilation with the on Management of the Difficult Airway. Anesthesiology.
esophageal tracheal combitube in cardiopulmonary resus- 1993;78:597–602.
citation. Promptness and effectiveness. Chest. 1988;93: 7. Bagheri SC, Stockmaster N, Delgado G, et al. Esophageal
781–784. rupture with the use of the Combitube: report of a case
3. Yardy N, Hancox D, Strang T. A comparison of two airway aids and review of the literature. J Oral Maxillofac Surg.
for emergency use by unskilled personnel. The Combitube 2008;66:1041–1044.
and laryngeal mask. Anaesthesia. 1999;54:172–197. 8. Foley LJ, Ochroch EA. Bridges to establish an emergency
4. Frass M, Frenzer R, Mayer G, et al. Mechanical ventilation airway and alternate intubating techniques. Crit Care Clin.
with the esophageal tracheal combitube (ETC) in the inten- 2000;16:429–444.
sive care unit. Arch Emerg Med. 1987;4:219–225.
DESIGN SERVICES OF

CHAPTER
26 Laryngeal Mask Airway

Paul G. Tarasi and Ryan C. Romeo
Concept was designed to separate the respiratory and gastrointes-

tinal tracts and provide higher airway sealing pressures,
thus allowing dependable positive pressure ventilation.
The laryngeal mask airway (LMA) has been in widespread
The Proseal LMA can be somewhat more challenging to
use by anesthesiologists in Europe since the 1980s, when
insert than the standard LMA device, due to its larger size
it was developed by Dr. A.I.J. Brain.1 It is used worldwide
and different conformation. This device can be placed
in the operating room (OR) to ensure airway patency dur-
freehand, or with an optional insertion tool. A newer
ing general anesthesia. The device is available in both re-
alternative, the LMA Supreme (LMA of North America)
usable and disposable forms (Fig. 26-1), and comprises
(Fig. 26-5) is a disposable, single-use device that incor-
a tube attached to an ovoid mask that is placed in the
porates a gastric port similar to the Proseal LMA, with an
hypopharynx and advanced to cover the glottic opening.
integral bite block and a premolded curved tube similar
When inflated, the cuff of this mask provides a seal around
to the Ambu AuraOnce. Both the standard LMA and the
the glottic aperture.2 However, this seal is inadequate at
Proseal LMA devices can be overinflated, with resultant
high peak inspiratory pressures, and leakage of inspira-
mucosal injury.5 Ideally, a manometer should be used to
tory gases is manifest, especially when pressures begin to
gauge the correct pressure of inflation, as recent evidence
exceed 30 cm H2O. In elective settings, spontaneous breath-
suggests that limiting cuff pressures to less than 60 cm
ing (as opposed to positive pressure ventilation) is preferred
H2O (44 mm Hg) results in significantly less postoperative
with the use of this device, but it can be used safely and
sore throat, dysphagia, and dysphonia.6
effectively for positive pressure ventilation if tidal volumes
One relatively new supraglottic airway, the i-gel
and peak inspiratory pressures are kept low (tidal volume
(Intersurgical Ltd, Wokingham, UK), resembles the LMA
should not exceed 8 mL/kg and peak inspiratory pressures
in shape and insertion technique but is made from a
should be limited to 20 cm H2O). Reusable LMA masks are
thermoplastic elastomer to conform to the perilaryngeal
typically made from silicone, whereas single-use devices
anatomy and does not have an inflatable cuff. This sim-
are often constructed with polyvinylchloride; however,
plifies use and may reduce the risk of compression injury.
some single-use devices such as the AES Ultra are made
Like the Proseal LMA and the LMA Supreme, this airway
with silicone. The LMA is manufactured in many sizes,
also incorporates a gastric channel. It is available in three
ranging from those for neonates to those for large adults.
adult sizes.
In adults, the usual range of sizes is 3, 4, and 5 (Fig. 26-2).
Multiple manufacturers have now begun to offer similar
devices, often with functional modifications. The Ambu
AuraOnce (Ambu, Ballerup, Denmark) (Fig. 26-3) is a Evidence
disposable LMA with an angled tube designed to follow
the natural curve of the supraglottic airway, with recent The LMA is effective for ventilation in the OR during
evidence suggesting increased ease of insertion compared many types of elective surgical cases.1,2 Originally used
with the original LMA design.3,4 Several other manufactur- mainly for cases in the supine position, recent evidence
ers offer LMAs with flexible, wire-reinforced tubes for use suggests that the LMA may be a useful airway tool for
in intraoral and other procedures that require positioning elective cases in the prone position as well.7–9 The LMA
of the airway tube away from the surgical field, with less has also been used as an emergency ventilation adjunct
risk of LMA dislodgement or malposition. in various circumstances.2,10,11 It can be used effectively
Because the LMA does not provide an intratracheal as a “bridge” to fiberoptic intubation, because a size 6.0
seal, regurgitation and aspiration are potential risks of its endotracheal tube (ETT) (or 7.0 in the size 5 LMA) may
use. This prompted the development of a version of the be passed through the LMA and into the glottis, while the
device that incorporates a gastric port to allow decom- lumen of the device effectively guides the fiberscope to
pression of the stomach after insertion. The Proseal LMA the laryngeal opening.11,12 The LMA has proven useful as
(LMA of North America, San Diego, CA, USA) (Fig. 26-4) a both an alternative to bag-valve-mask (BVM) ventilation
204

CHAPTER 26 ■ LARYNGEAL MASK AIRWAY 205
in cardiopulmonary arrest and as a rescue device in dif- Very few reports exist describing failure of an LMA in a
ficult airway management. Among intensive care nurses, cannot intubate, cannot ventilate (failed airway) situation.20
Martin13 found that the LMA proved easier to use and pro- Thus the considerable experience with the LMA in unex-
vided superior tidal volumes with less likelihood of air- pectedly difficult airway management in the OR substanti-
way obstruction than BVM ventilation with or without an ates its use when emergent ventilation is required in other
oral airway. When untrained volunteers were assessed for settings, such as the emergency department or intensive
the ability to ventilate patients under general anesthesia, care unit, because it can be inserted so quickly and with
Alexander14 described marked improvement in the suc- a high expectation of success.21 Its use may allow progres-
cess of ventilation and oxygenation when the LMA was sion to a more definitive airway, whether translaryngeal or
used, compared with BVM ventilation. He reported a 43% surgical, in a controlled and orderly manner, as opposed to
rate of failure to ventilate effectively with the latter device, a frenetic procedure in a severely hypoxemic patient. Given
whereas the LMA was successful in all but 13% of cases. its utility in emergency circumstances, the LMA has become
Likewise, Smith15 found that anesthetists were better able the intervention of choice for the cannot intubate, cannot
to maintain oxygen saturation and a patent airway in ventilate situation in the OR, as directed by the 2003 diffi-
64 patients under general anesthesia randomly assigned cult airway management guidelines of the American Society
to ventilation using the LMA as opposed to a face mask. of Anesthesiologists.22
In an evaluation of the utility of LMA for prehospital Various case reports of gastric aspiration related to
care, Pennant16 described placement of LMA by paramed- LMA use have been published.23 Several of these patients
ics in 100% of cases in less than 40 seconds, whereas ETT had predispositions to regurgitation due to obesity, sur-
placement took more than twice that long and resulted gical position, or emergency procedures. In a large meta-
in 31% misplacement. Davies17 described placement of an analysis of the literature, Brimacombe24 concluded that the
ETT or LMA in a mannequin model by paramedics with incidence of reported aspiration of gastric contents with
little training: 94% of LMA insertions were successful, the use of the LMA device was no higher than that reported
compared with only 51% of ETT insertions. with the use of the ETT in the elective surgical patient.
The LMA has been well established for effectiveness dur- The Proseal LMA provides a higher sealing pressure
ing difficult airway management in the OR.10–12 Experienced than the standard LMA, facilitating mechanical ventila-
practitioners can usually insert the LMA within 20 seconds, tion, and allows passage of a gastric tube to decompress
with a success rate of 98%.18 Parnet19 described the use of the stomach, offering a measure of protection against as-
LMA as the adjunct of first choice by academic anesthe- piration.25 Like the LMA, it has proven effective in man-
siologists facing difficult intubation or difficult ventilation agement of the difficult airway and for rescue in cannot
situations in 17 cases over 2 years, with a 94% success rate, intubate, cannot ventilate situations.26 Failure of place-
whereas other modalities were significantly less successful. ment with the device may be as high as 4%.27 Proseal LMA
FIG U RE 26-1 LMA Unique (single-use).
Airway tube
15 mm adaptor
Aperture bars Inflation pilot balloon
Cuff

F I GUR E 2 6 -2 LMA Unique in sizes 3, 4, and 5 (for

patients less than 50 kg, 50 to 70 kg, and greater
than 70 kg, respectively). Note the aperture bars at
the distal end of the airway tube, to prevent tube
occlusion by the epiglottis.
F I GUR E 2 6 -3 Ambu AuraOnce (single-use,

curved airway tube).
is offered in two pediatric sizes (2 and 3), and has been ● Preoxygenation is optimal (but in cannot intubate, cannot
demonstrated to provide a more effective seal with less ventilate scenarios will be impossible)
gastric insufflation than the standard LMA in a population
of 30 children (10 to 21 kg).28
Procedure for Insertion
of LMA (Figs. 26-6–26-14)
Preparation for Insertion
● Open mouth, extend head with nondominant hand
● Preparation for direct laryngscopy (see Chapter 5) ● Slide the dorsal surface of the LMA along the hard palate
● Estimate size of LMA necessary, based on patient size, of the patient
weight (see Table 26-1) ● Hold the device like a pencil in the right hand, with index
● Lubricate dorsal (top) surface of LMA finger between the tube and mask at its base
● Check integrity of cuff and deflate completely ● Use index finger to guide LMA into pharynx, initially
● Anesthetized or unconscious patient in neutral exerting force cephalad, against the hard palate
position

FIG U RE 26-4 Proseal LMA (note

gastric port).
(Courtesy of LMA North America, Inc.)
FIG U RE 26-5 LMA Supreme (single-use, note

gastric port and curved tube).
(Courtesy of LMA North America, Inc.)

Table 26-1
LMA Sizes and Inflation Volumes
Size of LMA Device Weight of Patient Maximum Inflation Volume (mL)a

1 Infants to 5 kg 4
1.5 5–10 kg 7
2 10–20 kg 10
2.5 20–30 kg 14
3 30–50 kg 20
4 50–70 kg 30
5 70–100 kg 40
6 (LMA Classic only) >100 kg 50
a
The manufacturer recommends that cuff pressures do not exceed 60 cm H2O. In sizing, the largest size that fits readily into the patient’s pharynx should
be chosen and inflated until there is no leak at 20 cm H2O inspiratory pressure.
F I GUR E 2 6 -6 LMA insertion: dorsal surface

pressed against the hard palate as LMA is
advanced toward pharynx, in cadaver specimen.

FIG U RE 26-7 LMA is advanced

into the pharynx.
FIG U RE 26-8 LMA in place over larynx.

F I GURE 2 6 -9 The cuff is now inflated to

create a seal around the larynx.
F I GUR E 2 6 -1 0 Preparing to insert the LMA.
● The index finger continues to exert force, assisting in the ● Confirm chest rise, breath sounds, end-tidal carbon diox-
acute bend that the mask and tube must negotiate to seat ide (ETCO2)
in the hypopharynx ● Secure the device
● Advance LMA into hypopharynx until resistance is felt
● Inflate the cuff (volume of air depends on the LMA size)

FIG U RE 26-11 Insertion of LMA in

elective situation in OR. Note position of
index finger to guide the device along the
hard palate and into the hypopharynx.
FIG U RE 26-12 Continue insertion until

resistance is met as LMA seats in
hypopharynx.
FIG U RE 26-13 LMA sliding along

hard palate as it is introduced toward the
pharynx.

F I GUR E 2 6 -1 4 Bronchoscopic view inside lumen

of LMA showing epiglottis just beyond grill at the
end of LMA lumen (epiglottis not folded down).
Procedure for Insertion Contraindications

of LMA with a Fixed Curve
in the Airway Tube ● Severe upper airway obstruction
● Full stomach or potential for gastric regurgitation (this
● Prepare as above
applies to elective use of the device)
● Ensure that the mouth is fully opened ● Planned positive pressure ventilation if peak airway pres-
● Place the tip of the LMA against the inner surface of the
sures are likely to exceed 20 cm H2O
upper teeth/hard palate
● Using a circular motion, advance the LMA along the hard
and soft palates until resistance is felt Complications
Practicality ● Regurgitation/aspiration of gastric contents
● Failure to seal over the glottis, with inadequate
● Inexpensive ventilation
● Portable and simple ● Gas leak at high peak inspiratory pressures (about 30% of
● Relatively unfamiliar for those not using it routinely; tidal volume is lost at inspiratory pressures greater than
requires use and practice for facility 30 cm H2O)
● May stimulate swallowing, cough, or hiccups when
inserted
Indications ● Laryngospasm
● Pharyngeal trauma during blind insertion
● Routine airway in OR ● Nerve injury due to compression (CN IX, X, XII)
● Difficult laryngoscopy ● Overinflation of cuff with pharyngeal mucosal injury
● Difficult ventilation
● First choice in OR for cannot intubate, cannot ventilate
scenario
● Planned bridge to fiberscopic intubation
REFERENCES 3. Sudhir G, Redfern D, Hall JE, et al. A comparison of the

disposable Ambu AuraOnce Laryngeal Mask with the re-
1. Brain AIJ. The laryngeal mask airway. Br J Anaesth. suable LMA Classic laryngeal mask airway. Anaesthesia.
1983;55:801–804. 2007;62:719–722.
2. Pennant JH, White PF. Laryngeal mask airway. 4. Shariffuddin II, Wang CY. Randomised crossover compari-
Anesthesiology. 1993;79:144–163. son of the Ambu AuraOnce Laryngeal Mask with the LMA

Classic laryngeal mask airway in paralysed anaesthetised 17. Davies PRF, Tighe SQM, Greenslade GL, et al. Laryngeal
patients. Anaesthesia. 2008;63:82–85. mask airway and endotracheal tube insertion by unskilled
5. Keller C, Brimacombe J. Mucosal pressure and oropharyn- personnel. Lancet. 1990;336:977–979.
geal leak pressure with the ProSeal versus laryngeal mask 18. Brimacombe JR, Berry A. Mallampati class and laryngeal
airway in anesthetized, paralyzed patients. Br J Anaesth. mask airway insertion. Anaesthesia. 1993;48:347–351.
2000;85:262–266. 19. Parnet JL, Colonna-Romano P, Horrow JC, et al. The
6. Seet E, Yousaf F, Gupta S, et al. Use of manometry for laryn- laryngeal mask airway reliably provides rescue ventilation in
geal mask airway reduces postoperative pharyngolaryngeal cases of unanticipated difficult tracheal intubation along with
adverse events. Anesthesiology. 2010;112:652–657. difficult mask ventilation. Anesth Analg. 1998;87:661–665.
7. Ng A, Raitt DG, Smith G. Induction of anesthesia and inser- 20. Patel SK, Whitten CW, Ivy R, et al. Failure of the laryngeal
tion of a laryngeal mask airway in the prone position for mask airway: an undiagnosed laryngeal carcinoma. Anesth
minor surgery. Anesth Analg. 2002;94(5):1194–1198. Analg. 1998;86:438–439.
8. Sharma V, Verghese C, McKenna PJ. Prospective audit on 21. Pollock CV Jr. The laryngeal mask airway: a comprehen-
the use of the LMA-Supreme for airway management of sive review for the emergency physician. J Emerg Med.
adult patients undergoing elective orthopaedic surgery in 2001;20:53–56.
prone position. Br J Anaesth. 2010;105(2):228–232. 22. Caplan RA, Benumof JL, Berry FA, et al. Practice guidelines
9. López AM, Valero R, Brimacombe J. Insertion and use for management of the difficult airway: an updated report
of the LMA Supreme in the prone position. Anaesthesia. by the ASA task force on management of the difficult air-
2010;65(2):154–157. way. Anesthesiology. 2003;98:1269–1277.
10. Benumof JL. Use of the laryngeal mask airway to facili- 23. Keller C, Brimacombe J, Bittersohl J, et al. Aspiration and
tate fiberoptic bronchoscopic intubation. Anesth Analg. the laryngeal mask airway: three cases and a review of the
1992;74:313–315. literature. Br J Anaesth. 2004;93:579–582.
11. Benumof JL. Laryngeal mask airway and the ASA difficult 24. Brimacombe JR, Berry A. The incidence of aspiration asso-
airway algorithm. Anesthesiology. 1996;84:686–699. ciated with the laryngeal mask airway: a meta-analysis of
12. Heath ML, Allagain J. Intubation through the laryngeal published literature. J Clin Anesth. 1995;7:297–303.
mask. Anesthesiology. 1991;46:545–548. 25. Brimacombe J, Keller C. The ProSeal laryngeal mask airway.
13. Martin PD, Cyna AM, Hunter WAH, et al. Training nursing Anesthesiol Clin North America. 2002;20:871–891.
staff in airway management for resuscitation. A clinical com- 26. Cook TM, Silsby J, Simpson TP. Airway rescue in acute
parison of the facemask and laryngeal mask. Anesthesiology. upper airway obstruction using a ProSeal laryngeal mask
1993;48:33–37. airway and an Airtree catheter: a review of the ProSeal
14. Alexander R, Hodgson P, Lomax D, et al. A comparison laryngeal mask airway in management of the difficult
of the laryngeal mask airway and Guedel airway, bag and airway. Anesthesia. 2005;60:1129–1136.
facemask for manual ventilation following formal training. 27. Gaitini LA, Vaida SJ, Somri M, et al. A randomized con-
Anesthesiology. 1993;48:231–234. trolled trial comparing the ProSeal Laryngeal Mask Airway
15. Smith I, White PF. Use of the laryngeal mask airway as with the Laryngeal Tube Suction in mechanically ventilated
an alternative to a face mask in outpatient arthroscopy. patients. Anesthesiology. 2004;101:316–320.
Anesthesiology. 1992;47:850–855. 28. Goldmann K, Jakob C. Size 2 ProSeal laryngeal mask airway:
16. Pennant JH, Walker MB. Comparison of the endotracheal a randomized, crossover investigation with the standard
tube and laryngeal mask in airway management by para- laryngeal mask airway in pediatric patients. Br J Anaesth.
medical personnel. Anesth Analg. 1992;74:531–534. 2005;94:385–389.

CHAPTER
27 Intubating Laryngeal
Mask Airway
Ryan R Wilson and William McIvor
Concept easy to use. Those with limited airway management

experience may be more successful with the ILMA than
with conventional methods. Timmerman et al1 showed
The intubating laryngeal mask airway (ILMA) (Fastrach,
that medical students ventilate and intubate quicker
LMA of North America, San Diego, CA, USA) is a deriva-
and more effectively via ILMA than by conventional
tion of the laryngeal mask airway (LMA) that facilitates both
bag-mask ventilation and laryngoscopy. Thirty medi-
ventilation and blind endotracheal intubation. The device
cal students, each intubated three patients using each
has several features that distinguish it from the standard
method. Ventilation was significantly more successful
laryngeal mask device. The intubating laryngeal mask con-
with the ILMA (97.8% vs 85.6%). Intubation was also
sists of a soft mask that fits over the larynx, attached to a
more successful using the ILMA (92.2% vs 40.0%). In
rigid stainless steel tube. The lumen of the tube has a larger
Australia, Agro2 described its use in 110 patients slated
internal diameter than the standard LMA and is attached
for general anesthesia, with 95% success. However, the
to a handle to facilitate insertion. This tube admits a flex-
authors encountered resistance to ETT insertion in 60%
ible, reinforced endotracheal tube (ETT) specifically manu-
of patients, which required some form of adjustment.
factured for this laryngeal mask. The device comes in three
The average time required for the authors to intubate
sizes for adults (3, 4, and 5), all of which can admit a range
patients was 79 seconds. In a multicenter study from
of ETT sizes, up to size 8.0. Other manufacturers have
the United Kingdom, Baskett3 assessed the efficacy of
begun to offer similar devices, such as the Air-Q Reusable
the ILMA in intubation of 500 patients undergoing gen-
Laryngeal Mask (Mercury Medical, Clearwater, FL, USA)
eral anesthesia, with 95% success in ventilation through
and Ambu Aura-I (Ambu Inc., Glen Burnie, MD, USA).
the mask portion of the device. The authors had 80%
Both provide a means of intubation through the device but
intubation success on the first attempt, with 4% of
do not have the steel barrel, handle, or epiglottic elevating
patients requiring three attempts, and an overall failure
bar (EEB), which are features of the ILMA.
rate of 4%. Brain4 used the ILMA in 150 patients under-
going general anesthesia, with successful ventilation of
all patients. In half of the patients, resistance to ETT
Evidence insertion through the device occurred, requiring one of
several described “adjusting maneuvers” before intuba-
The ILMA device has proven useful for managing the tion was accomplished. The study included 13 patients
difficult airway in various settings. The popularity of with potential or known difficult airway anatomy, all
the LMA in Europe and around the world has led to of whom were intubated successfully. Four differ-
ready acceptance of the ILMA. The ILMA is relatively ent adjusting maneuvers were suggested (Table 27-1),
Table 27-1
Adjustment Maneuvers for Blind Intubation through the ILMA3
Depth of Resistance Likely Cause of Resistance Corrective Action

0.0–1.5 cm EEB trapped behind cricoid cartilage Replace ILMA with next smaller size
1.5–2.0 cm Epiglottis folded down over glottis Remove ETT, swing ILMA back out, up to
opening 6.0 cm (with cuff up), replace in pharynx
2.0–4.0 cm EEB lying too high Replace ILMA with next larger size
4.0–6.0 cm ETT tip wedged between mask tip and Replace ILMA with small size
cricoid cartilage
214

CHAPTER 27 ■ INTUBATING LARYNGEAL MASK AIRWAY 215
depending upon the depth at which resistance to the in whom direct laryngoscopy had failed in the emergency
ETT advancement was encountered.3 department. The authors commented that “proficiency in
In 38 patients with known difficult airway anatomy its [ILMA] use requires practice under controlled condi-
(based on patient history or physical examination), Joo5 tions” and suggested that “the emergency physician seek
assessed the utility of the ILMA compared with awake out elective practice” before it is used for airway manage-
intubation with the fiberoptic bronchoscope (FOB). All ment under emergent circumstances.
awake FOB attempts were successful, but only half of the Use of the ILMA for out-of-hospital difficult airway man-
patients could be intubated blindly with the ILMA. The agement by anesthesia-trained emergency physicians was in-
other half required use of a bronchoscope, and 10% re- vestigated by Timmerman et al.13 They reported successful
quired involvement of a second operator to place the ETT. ventilation and intubation using the ILMA in all 11 patients
In another evaluation of this device in patients with known upon whom it was employed, including in 8 patients in
or suspected difficult airways, Ferson et al6 evaluated the whom either blind nasal or oral intubation had failed. Busch
utility of the ILMA in 257 patients: 78% after induction of et al14 reported 97% successful ventilation and 86% success-
anesthesia, and 20% awake, with topical anesthesia (in 2% ful intubation using the ILMA by untrained field emergency
of cases, patients were unconscious and no anesthetic was nurses in out-of-hospital cardiac arrest situations. They con-
provided). The authors were able to successfully ventilate cluded that the ILMA was an effective alternative to direct
all of these patients, and ETT insertion was accomplished laryngoscopy for endotracheal intubation in difficult airways
blindly in 96.5% of the 200 in whom it was attempted (the outside the hospital by untrained personnel.
remainder were intubated with FOB, using the ILMA as an
introducer device), 75% on the first attempt.
In a study of the efficacy of the ILMA in obese pa- Preparation (Figs. 27-1
tients, Combes et al7 found that the device required less and 27-2)
adjusting maneuvers and fewer attempts at blind place-
ment than in lean subjects, with similar overall intuba-
● Preparation for direct laryngoscopy (see Chapter 5)
tion success rates (96% vs 94%, respectively). Among
● Estimate size of ILMA necessary for patient, based on size
anesthetized patients where in-line cervical immobiliza-
and weight
tion was used to simulate cervical spine trauma, Komatsu
● Lubricate both ILMA (dorsal cuff) and the reinforced ETT
et al8 found that the ILMA was simpler and quicker to
● Check cuff of both ILMA and ETT
insert than another supraglottic ventilation device, the
● Place ETT through LMA to ensure smooth function and
laryngeal tube, and allowed ventilation with larger tidal
lubrication
volumes. Other case series also indicate that the ILMA
● Anesthetized, preoxygenated patient, in neutral or sniffing
can be used safely in patients with cervical spine injuries
position
or disorder.9,10 In a retrospective review by Ferson et al,6
70 patients with known unstable c-spines and immobi-
lized with rigid collars were successfully intubated blindly
using an ILMA with a 92.6% success rate on the first at- Procedure for Intubation
tempt. In five cases (7.4%), two attempts were needed. with Intubating LMA
FOB assistance was used electively in two of the five cases (Figs. 27-3–27-17)
for the second attempt. The use of the ILMA was not im-
plicated in any new neurologic deficits in these patients. ● Open mouth, place the ILMA into the pharynx using the
Less data exist related to use of the ILMA in emer- handle to rotate the mask into the hypopharynx until
gency intubation, outside the operating room (OR). Asai,11 resistance is felt
simulating trauma resuscitation with manual in-line im- ● Inflate ILMA cuff, confirm optimal ventilation
mobilization of the cervical spine in anesthetized patients, ● Stabilize ILMA and insert ETT through it with longitudi-
evaluated the ILMA for intubation in 40 patients. The nal black stripe facing cephalad
ILMA was used in conjunction with FOB to ensure cor- ● When black band on ETT (15 cm from the tip) reaches
rect placement, and this tandem was compared with direct the proximal lumen of LMA device, the tip of the ETT is
laryngoscopy with use of a bougie. The authors reported at the EEB at the distal end of LMA lumen
85% success of intubation with the ILMA under these cir- ● Advance ETT, lifting gently on the handle of the ILMA device
cumstances, compared with less than half of the patients ● If resistance is encountered, note depth and use adjusting
in the laryngoscopy-bougie group being successfully intu- maneuvers as necessary (see Table 26-1)
bated with these conditions. Rosenblatt12 reported three ● When ETT advances smoothly with no resistance, inflate
cases of successful intubation with the ILMA in patients ETT cuff
DESIGN SERVICES OF

F I GURE 2 7 -1 The intubating LMA and its

push rod and dedicated ETT. Steel-reinforced Steel handle to
anatomically-curved facilitate LMA
airway tube placement Pilot balloon
for ETT
Push rod to
stabilize ETT during
LMA reoval
Epiglottic
elevating
bar
15mm adaptor
ETT (removed from ETT)
advanced
through
LMA
Pilot balloon
for LMA cuff
F I GUR E 2 7 -2 ILMA in three sizes for adults.
● Ventilate patient and confirm ETT position ● More complex than standard LMA: ETT insertion
● Remove 15-mm adaptor from the ETT, deflate ILMA, and requires multiple attempts at times; adjustment maneu-
remove it using the push rod vers must be well understood and removal of LMA
● Grasp ETT with fingers (or Magill forceps) when it is without moving ETT can be awkward. Bear in mind
visible or palpable, continue LMA removal that, depending on the clinical scenario, removing the
● Reattach 15-mm adaptor to ETT, begin ventilation, and LMA may not be immediately necessary (eg, the patient
reconfirm ETT position may have other pressing physiologic problems, such as
● Secure ETT active hemorrhage that must be addressed) and removal
of the LMA can be accomplished as soon as practical
thereafter.
Practicality ● Unfamiliar to many outside of the OR environment;
requires use and practice for facility
● Reasonably expensive ($1,500 for three adult sizes)
● Portable
DESIGN SERVICES OF

FIG U RE 27-3 Placement of ILMA into pharynx

of cadaver specimen.
FIG U RE 27-4 ILMA in place for ventilation.
DESIGN SERVICES OF

F I GU R E 2 7 -5 ILMA inflated to seal glottis.
F I GU R E 2 7 -6 ETT placed through the ILMA,

entering the airway.
DESIGN SERVICES OF

FIG U RE 27-7 ETT passing into trachea.
FIG U RE 27-8 After the ETT is confirmed

to be in the airway, the ILMA cuff is deflated
and the ILMA device carefully removed. The
ETT adaptor must be removed first.
DESIGN SERVICES OF

F I GUR E 2 7 -9 Use of push rod to stabilize

ETT during LMA removal.
F I GU R E 2 7 -1 0 Grasping ETT with forceps

or fingers as ILMA is extracted from mouth.
DESIGN SERVICES OF

FIG U RE 27-11 ETT now in place and ventilation is

reinitiated and tube fixed.
FIG U RE 27-12 ILMA insertion.
FIG U RE 27-13 ILMA in correct position and

ventilation initiated.
DESIGN SERVICES OF

F I GUR E 2 7 -1 4 ETT insertion with black line

facing cephalad. When the black band at 15 cm on
the ETT reaches the lumen of the ILMA, the ETT tip
is beginning to push into the pharynx, moving the
EEB out of the way.
F I GUR E 2 7 -1 5 Adaptor attached to ETT and

ventilation confirmed.
F I GUR E 2 7 -1 6 Use of push rod to remove LMA.
DESIGN SERVICES OF

FIG U RE 27-17 Grasping ETT with fingers to

stabilize as ILMA is removed from mouth.
Indications Complications
● Predicted difficult airway ● Regurgitation/aspiration of gastric contents

● Difficult ventilation and/or intubation ● Pharyngeal trauma
● Routine airway management for elective OR cases ● Nerve injury due to prolonged compression (if LMA is not
removed)
● Failure to seal and/or ventilate with LMA
Contraindications ● ETT misplacement
● Inability to advance ETT
● Severe upper airway obstruction
REFERENCES 6. Ferson DZ, Rosenblatt WH, Johansen MJ. Use of the

intubating LMA-Fastrach in 254 patients with difficult-
1. Timmerman A, Russo SG, Crozier TA, et al. Novices to-manage airways. Anesthesiology. 2001;95:1175–1181.
ventilate and intubate quicker and safer via ILM than by 7. Combes X, Sauvat S, Leroux B, et al. Intubating laryngeal
conventional bag-mask ventilation and laryngoscopy. mask airway in morbidly obese and lean patients: a com-
Anesthesiology. 2007;107:570–576. parative study. Anesthesiology. 2005;102:1106–1109.
2. Agro F, Brimacombe J, Carassiti M, et al. The intubating 8. Komatsu R, Nagata O, Kamata K, et al. Comparison of
laryngeal mask. Anesthesiology. 1998;53:1084–1090. the intubating laryngeal mask airway and laryngeal tube
3. Baskett PJF, Parr MJA, Nolan JP. The intubating laryngeal placement during manual in-line stabilization of the neck.
mask. Results of a multicentre trial with experience of Anaesthesia. 2005;60:113–117.
500 cases. Anesthesiology. 1998;53:1174–1179. 9. Wong JK, Tongier WK, Armbruster SC, et al. Use of the
4. Brain AIJ, Verghese C, Addy EV, et al. The intubating laryngeal intubating laryngeal mask airway to facilitate awake orotra-
mask II. A preliminary clinical report of a new means of intu- cheal intubation in patients with cervical spine disorders.
bating the trachea. Br J Anaesth. 1997;79:704–709. J Clin Anesth. 1999;11:346–348.
5. Joo HS, Kapoor S, Rose DK, et al. The intubating laryngeal 10. Schuschnig C, Waltl B, Erlacher W, et al. Intubating laryn-
mask airway after induction of general anesthesia versus geal mask and rapid sequence induction in patients with
awake fiberoptic intubation in patients with difficult air- cervical spine injury. Anaesthesia. 1999;54:793–797.
ways. Anesth Analg. 2001;92:1342–1346.
DESIGN SERVICES OF

11. Asai T, Murao K, Tsutsumi T, et al. Ease of tracheal intuba- 13. Timmermann A, Russo SG, Rosenblatt WH, et al. Intubating
tion through the intubating laryngeal mask airway during laryngeal mask airway for difficult out-of-hospital air-
manual in-line head and neck stabilization. Anesthesiology. way management: a prospective evaluation. Br J Anaesth.
2000;55:82–85. 2007;99(2):286–291.
12. Rosenblatt WH, Murphy M. The intubating laryngeal mask: 14. Busch I, Claes D, Thomsin S, et al. Effectiveness of ILMA
use of a new ventilating-intubating device in the emergency used by nurses during out of hospital cardiac arrest resusci-
department. Ann Emerg Med. 1999;33:234–238. tation. Acta Anaesthesiol Belg. 2009;60:235–238.
DESIGN SERVICES OF

CHAPTER
Other Supraglottic
Airway Devices
28 cn
Kristin Schreiber and Paul Bigeleisen
Concept 3. The pharyngeal cuff only includes the COBRA.

4. The cuffless anatomically shaped sealers include de-
vices such as the Streamlined Liner of the Pharyngeal
There are several indications for the use of a supraglottic
Airway (SLIPA).
airway device (SGA), particularly when the patient can-
not be intubated or ventilated using bag-mask ventilation.
In this case, successful placement of an SGA defines an
emergent versus a nonemergent pathway. Although the SPECIFIC DEVICES
laryngeal mask airway (LMA) and Combitube have tradi-
Laryngeal Tube (King LT and King LTS)
tionally been used in this context, the devices discussed in
this chapter can also serve this purpose. Other important Description: The LT is a blindly placed SGA containing two
uses include airway management by practitioners with balloons, or cuffs, one superior, and one inferior, to the glot-
variable experience using direct or optically guided intu- tic opening (Fig. 28-1A, B). It is designed to fit with the dis-
bation. In the operating room, SGAs can be used in elec- tal (inferior) balloon in the esophagus, sealing this off, and
tive, spontaneous ventilation cases. In addition, some of the proximal (superior) balloon in the posterior pharynx,
these devices allow multiple simultaneous functions (ven- posterior to the base of the tongue and epiglottis. Inflation
tilation, intubation, and gastric decompression). of 20 to 90 cc of air at a single pilot balloon fills both cuffs
One of the most important qualities when selecting simultaneously, creating a seal of approximately 60 cm H2O
an SGA is its ease of use, as it is often used in an emer- proximal and distal to the glottis. Positive pressure ventila-
gent situation. Improper placement of the various SGAs tion can then be achieved through multiple apertures located
is also an important consideration, as obstruction or air between these cuffs. Obstruction does not appear to be a
leak can result in difficult ventilation, ultimately increas- problem with the new King LTs, which have multiple venti-
ing the risk of gastric distension and aspiration. Although lation apertures4 compared with earlier versions of the King
supraglottic airways have a design that seeks to protect the tube. The most commonly used LT is the King LT, which
lungs from aspiration of gastric contents or of pharyngeal was first created by VBM in Germany in 1998 and approved
secretions/blood, an endotracheal tube (ETT) has gener- for use in the United States in 2003. The King LTS also has
ally been considered to provide superior protection from a separate lumen for suction, through which an orogastric
aspiration. The results of some studies, however, suggest tube can be passed. The LT is similar to the Combitube in
that aspiration occurs in 11% of cases even when ETTs are many respects. Unlike the Combitube, however, it does not
used properly.1 In a comparison study of aspiration, epi- have an option of ventilating through two separate lumens.
sodes of hypopharyngeal pH <4 were similar in incidence This device is available in sizes 1 to 5:
between a COBRA, LMA, laryngeal tube (LT), and ETT,
suggesting that the ETT may not provide superior protec- Size 1 1.5 2 2.5 3 4 5
tion against aspiration.2 Finally, the cost and disposability Weight ≤5 5–10 10–20 20–30 30–50 50–70 ≥70 in kg
of the device impacts the ability of trainees to practice and
become proficient with the device.
Evidence
Categorization of Supraglottic Airways
One proposed categorization scheme for supraglottic air- Some practitioners feel that the LT is easier to insert than
ways is based on the mechanism of sealing around the the Combitube and has a lower incidence of accidental
glottic aperture.3 laryngeal insertion because of its S shape. Additionally, its
smaller size compared with the Combitube may be use-
1. The perilaryngeal cuffed group includes the LMA and ful in patients with a smaller mouth opening. There have
all of its variants (reviewed in Chapter 26). been several studies involving the LT, investigating time
2. The pharyngeal and esophageal cuffed devices include to and ease of placement, as well as leak pressures, in com-
the Combitube and LT (King). parison with other SGAs.
225

F I GUR E 2 8 -1 A: King LT airway. B: King LT airway pictured in the airway with proximal and distal cuffs inflated.
Emergency use in field: In one study investigating use of increased pressure required for leak with King LT, theo-
SGAs by emergency medical technicians (EMTs) during retically decreasing risk of gastric insufflation compared
field runs in a rural setting, the LT was placed on first attempt with the LMA.11–13 However, in another study it was noted
12/13 times, and in some of these cases after failed attempts that there was no significant difference in leak pressures
with ETT (6/13) and Combitube (3/13).5 In a larger study between the SGAs COBRA, LT, and LMA.2
of both the King LTD and LTDS, emergency physicians and
EMTs had a 98% success rate in placement. Furthermore, Use as a difficult airway device: In another study, use
the time to placement in users who had 5 or less ETT of the King device was investigated in cases of failure
insertions was: <45 seconds (n = 120), 46 to 90 seconds to successfully intubate using an ETT (after three tries).
(n = 20), >90 (n = 7).6 In one study, the force to dis- Placement and use of the King airway was successful 100%
lodge various airway devices in cadavers was measured. of the time.14
The ETT, LMA, and King airway required similar forces,
whereas the Combitube required more force.7 This study Manikin/simulation studies: In some European studies
may have relevance to patients in transport. using manikins, results have also suggested that the LT
produces better ventilation, less gastric distention, and
Use in the operating room: In a study of the King LT by greater ease of insertion than the LMA or Combitube.15–17
experienced providers in operative cases with spontaneous In several studies of prehospital emergency services staff,
ventilation, the ease of insertion was notable. The initial and medical students in a simulator setting, it has been
insertion time was <5 seconds in 98%, and 5 to 15 seconds shown that less time was required for insertion of the
in the remaining patients. Only 19% of these insertions King LT (24.4 seconds) compared with a Combitube
required repositioning, whereas 2% required three trials (37.9 seconds) and also that the practitioners expressed a
at positioning. A relatively low incidence of sore throat preference for the King LT.18–20 The LT has been revised in
was also described in this investigation, with 22% noted design several times throughout the years, and some of the
at 1 hour and 15% at 24 hours.8 In two other studies in most recent revisions have occurred since these studies.
humans comparing the LT with the Combitube, it was
revealed that faster insertion times (39 vs 79 seconds) and Procedure for LT Insertion
more successful insertion (100% vs 87%) were possible Open the mouth with the nondominant hand, grasp the
with the LT than Combitube. There was no significant mandible and pull the mandible forward. With the LT
gastric insufflation observed in either case, but LT had a device rotated laterally 45° to 90°, insert it behind the
lower seal pressure (26 vs 36 cm H2O).9,10 Several stud- tongue. Advance the tube until the standard connector is
ies have compared the LT to LMA, and the authors found just aligned with the patient’s teeth. Inflate the pilot cuff to
DESIGN SERVICES OF

CHAPTER 28 ■ OTHER SUPRAGLOTTIC AIRWAY DEVICES 227
60 cm H2O pressure or to the minimum volume necessary Evidence

to seal the airway at the peak ventilatory pressure. Attach
the LTA to the breathing circuit, begin ventilation, and
Use in the operating room. There have been several stud-
withdraw the LTA until ventilation is optimal. Confirm
ies in which the Cobra device was compared with the LMA.
effective ventilation using auscultation, measured tidal
In one, the authors described a better airway seal with the
volume, and capnometry. Readjust the cuff pressure to a
Cobra compared with LMA.21 In another, Schebesta et al
volume that just seals the airway and secures the device
noted leak pressures of 24 cm in the Cobra versus 20 cm
to the patient.
in the LMA, suggesting that the Cobra provides a better
Cobra Perilaryngeal Airway airway seal than the LMA during ventilation. Conversely,
there were greater detectable waste gasses at the level
Description: This SGA is essentially a breathing tube that
of the anesthesiologist in the Cobra group. In the same
broadens distally into the shape of the head of a Cobra study, the authors found that insertion times were similar
snake (Fig. 28-2A, B). It has a single cuff located just prox- (15 seconds in Cobra vs 16 seconds in LMA). Insertion
imal to this head, which, when inflated, serves to seal off failed in 2 out of 30 in the Cobra group, but these 2 pa-
the distal end from the upper airway. The slotted openings tients were also unable to be fit with LMA22 after Cobra in-
of the Cobra head hold both the soft tissue and the epi- sertion failed. In a review of six clinical trials, the authors
glottis away from the glottic aperture. An ETTof size 8 or found mostly similar insertion times between the Cobra,
smaller can be advanced through the Cobra Perilaryngeal LMA and LT. Half of these studies showed slightly higher
Airway (PLA) sizes 4–6. leak pressures (better seal) with Cobra. However, in sev-
It is available in eight sizes and can be used for neo- eral of these studies it was noted that there was more fre-
nates as well as for infants: quent blood staining on the Cobra device.23 Another study
was terminated early because of two cases of aspiration.24
Size 0.5 1 1.5 2 3 4 5 6
Weight 2.5–7.5 5–15 10–35 30–50 40–100 70–130 100–160 ≥160
Therefore, some practitioners do not to use the Cobra in
in kg cases where there is an increased risk of aspiration.
Procedure for CobraPLA Insertion
The internal diameter of the breathing tube for adults
All distal portions of the device should be lubricated
has a range of 10.5 to 12.5 mm and all sizes can be attached
before insertion. After induction of general anesthesia,
to an 11 mm adapter. The cuff volume ranges from <8 mL,
place the patient’s head in full extension with the mouth
for neonates, to 65 to 85 mL, for small and large adults,
open, and the mandible pulled upward. The package
respectively.
A B
F I GU R E 28 - 2 A: Cobra Perilaryngeal Airway. B: Cobra pictured in the airway of a manikin with inflated cuff.
DESIGN SERVICES OF

insert recommends folding the fully deflated pharyngeal pool, theoretically reducing the risk of pulmonary aspira-
cuff backward away from the Cobra head to facilitate insertion. The potential advantage of an anatomically shaped,
tion. Insert the device toward the hard palate. When the tip cuffless device is that it may prevent nerve damage to the
reaches the back of the mouth, advance the device toward hypoglossal or recurrent laryngeal nerves from pressure
and past the soft tissues of the hypopharynx until moderate effects that may occur with cuffed devices. No studies
resistance is felt. Inflate the cuff gradually until ventilation have substantiated this hypothesis.
is possible without a leak. Cuff pressure should be <25 cm There are seven adult sizes (47 to 57) with color-
H2O. All sizes connect to a standard, 15 mm internal diam- coded connectors. The number (in mm) indicates the
eter connector. Newer versions (CobraPlus) have CO2 sam- width at the bridge. The choice of size is most easily done
pling line and temperature probe within the device that can by a comparison with similar LMA sizing:
be directly plugged in. Prior to removal, secretions should
be suctioned and the cuff completely deflated. SLIPA size 47 49 and 51 51 and 53 55 and 57
LMA 2.5 3 4 5 Equivalent
Streamlined Liner of the Pharyngeal Airway
Description: The SLIPA is a noncuffed, single use SGA
made of latex-free soft plastic (ethylene vinyl-acetate copo- Evidence
lymer) in the shape of a pressurized pharynx (Fig. 28-3).
It is a hollow, blow-molded chamber shaped like a boot, In one investigation, the authors noted that the SLIPA
or slipper. The body has an anterior opening that faces was easier to insert than LMA (94% vs 89% on first at-
the patient’s laryngeal inlet, through which ventilation tempt) by inexperienced practitioners (medical stu-
occurs. The toe of the chamber sits in the entrance to dents).25 Conversely, in another study the practitioners
the esophagus. The bridge in the center of the chamber found it more difficult to insert this device than the
with its two lateral bulges fits into the pyriform fossae LMA, requiring a longer time (10.5 vs 7.3 seconds),
at the base of the tongue, which it displaces away from with lower first time success (73% vs 93%), and blood
the posterior pharyngeal wall. This may help to prevent on device in 40% of cases, versus only 6% with the LMA.
the epiglottis from closing on the glottis. The heel of the There was no difference in the hemodynamic changes
chamber anchors the device in position over the soft pal- in patients on insertion, and once in place there was no
ate and nasopharyngeal opening. It also contains a 50 mL difference in success of ventilation, leak pressures, or
empty internal space where pharyngeal secretions can gastric distention.26
F IG U R E 2 8 -3 SLIPA.
DESIGN SERVICES OF

CHAPTER 28 ■ OTHER SUPRAGLOTTIC AIRWAY DEVICES 229
The protection that this device offers against aspiration ● All three of these devices will likely be unfamiliar to those
was studied in a simulated model of airway regurgitation, outside the operating room and will require practice on
which showed that the device was able to trap aspiration manikins or normal patients for facility in their use
contents. However, the simulated airway model was cre-
ated using the SLIPA as a template. Thus, this study may Indications
not apply to clinical settings.27
Procedure for SLIPA Insertion ● Elective airway during surgery

● Emergency ventilation when face mask ventilation fails
To insert the device, the patient should be under gen-
eral anesthesia with his/her head in the sniffing position.
The patient’s mouth is opened and the device advanced Contraindications
toe first with the bridge side oriented toward the tongue
until it reaches the entrance of the esophagus, where it ● Inaccessibility of the oral cavity
seals against the cricopharyngeus sphincter. If obstruction ● Full stomach or aspiration risk (except in emergencies)
occurs immediately after the insertion, it is likely that the ● Severe supraglottic obstruction
epiglottis is folded down by the device. This should be cor-
rected by extending the head and performing a jaw thrust.
If the patient emerges from general anesthesia with
Complications
the SLIPA in place, a bite block may be needed to ensure
continued ventilation. ● Inability to ventilate
● Potential pharyngeal or esophageal trauma from insertion
● Regurgitation and aspiration of gastric contents
Practicality ● Overinflation of cuffs, with resultant pharyngeal mucosal
injury
● Portable ● Injury to glossopharyngeal or superior laryngeal nerves
● Inexpensive secondary to pressure against mucosa in pharynx.
REFERENCES oesophageal-tracheal combitube during routine surgical

procedures. Eur J Anaesthesiol. 2005;22:341–346.
1. Blunt MC, Young PJ, Patil A, et al. Gel lubrication of 10. Dörges V, Ocker H, Wenzel V, et al. The Laryngeal Tube S: a
the tracheal tube cuff reduces pulmonary aspiration. modified simple airway device. Anesth Analg. 2003;96:618–621.
Anesthesiology. 2001;95:377–381. 11. Brimacombe J, Keller C, Brimacombe L. A comparison of the
2. Khazin V, Ezri T, Yishai R, et al. Gastroesophageal regur- laryngeal mask airway ProSeal and the laryngeal tube airway
gitation during anesthesia and controlled ventilation with in paralyzed anesthetized adult patients undergoing pressure-
six airway devices. J Clin Anesth. 2008;20:508–513. controlled ventilation. Anesth Analg. 2002;95:770–776.
3. Miller DM. A proposed classification and scoring system for 12. Asai T, Hidaka I, Kawachi S. Efficacy of the laryngeal tube by
supraglottic sealing airways: a brief review. Anesth Analg. inexperienced personnel. Resuscitation. 2002;55:171–175.
2004;99:1553–1539. 13. Miller DM, Youkhana I, Pearce AC. The laryngeal mask
4. Cook TM, Hommers C. New airways for resuscitation? and VBM laryngeal tube compared during spontaneous
Resuscitation. 2006;69:371–387. ventilation. A pilot study. Eur J Anaesthesiology. 2001;18:
5. Russi CS, Hartley MJ, Buresh CT. A pilot study of the King 593–598.
LT supralaryngeal airway use in a rural Iowa EMS system. 14. Guyette FX, Wang H, Cole JS. King airway use by air medi-
Int J Emerg Med. 2008;1:135–138. cal providers. Prehosp Emerg Care. 2007;11:473–476.
6. Schalk R, Engel S, Meininger D, et al. Disposable laryn- 15. Genzwürker H, Hundt A, Finteis T, et al. Comparison
geal tube suction: standard insertion technique versus two of different laryngeal mask airways in a resuscitation
modified insertion techniques for patients with a simulated model. Anasthesiol Intensivmed Notfallmed Schmerzther.
difficult airway. Resuscitation. 2011;82:199–202. 2003;38:94–101.
7. Carlson JN, Mayrose J, Wang HE. How much force is 16. Genzwürker H, Finteis T, Hinkelbein J, et al. First clini-
required to dislodge an alternate airway? Prehosp Emerg cal experiences with the new LTS. A laryngeal tube with an
Care. 2010;14:31–35. oesophageal drain Anaesthesist. 2003;52:697–702.
8. Hagberg C, Bogomolny Y, Gilmore C, et al. An evaluation 17. Wiese CH, Bahr J, Graf BM. [“Laryngeal Tube-D” (LT-D)
of the insertion and function of a new supraglottic airway and “Laryngeal Mask” (LMA)]. Dtsch Med Wochenschr.
device, the King LT, during spontaneous ventilation. Anesth 2009;134:69–74.
Analg. 2006;102:621–625. 18. Tumpach EA, Lutes M, Ford D, et al. The King LT versus
9. Bein B, Carstensen S, Gleim M, et al. A comparison of the the Combitube: flight crew performance and preference.
proseal laryngeal mask airway, the laryngeal tube S and the Prehosp Emerg Care. 2009;13(3):324–328.
DESIGN SERVICES OF

19. Russi CS, Wilcox CL, House HR. The laryngeal tube device: Liner of Pharyngeal Airway (SLIPA) supraglottic airways.
a simple and timely adjunct to airway management. Am Can J Anaesth. 2008;55:177–185.
J Emerg Med. 2007;25:263–267. 24. Cook TM, Lowe JM. An evaluation of the Cobra
20. Trabold B, Schmidt C, Schneider B, et al. Application of Perilaryngeal Airway: study halted after two cases of pul-
three airway devices during emergency medical training by monary aspiration. Anaesthesia. 2005;60:791–796.
health care providers—a manikin study. Am J Emerg Med. 25. Hein C, Owen H, Plummer J. Randomized comparison of
2008;26:783–788. the SLIPA (Streamlined Liner of the Pharynx Airway) and
21. Akça O, Wadhwa A, Sengupta P, et al. The new perilaryn- the SS-LM (Soft Seal Laryngeal Mask) by medical students.
geal airway (CobraPLA) is as efficient as the laryngeal mask Emerg Med Australas. 2006;18:478–483.
airway (LMA) but provides better airway sealing pressures. 26. Choi YM, Cha SM, Kang H, et al. The clinical effectiveness
Anesth Analg. 2004;99:272–278. of the streamlined liner of pharyngeal airway (SLIPA)
22. Schebesta K, Lorenz V, Schebesta EM, et al. Exposure to compared with the laryngeal mask airway ProSeal dur-
anaesthetic trace gases during general anaesthesia: CobraPLA ing general anesthesia. Korean J Anesthesiol. 2010;58:
vs. LMA classic. Acta Anaesthesiol Scand. 2010;54(7): 450–457.
848–854. 27. Miller DM, Light D. Laboratory and clinical comparisons of
23. Hooshangi H, Wong DT. Brief review: the Cobra the Streamlined Liner of the Pharynx Airway (SLIPA) with
Perilaryngeal Airway (CobraPLA) and the Streamlined the laryngeal mask airway. Anaesthesia. 2003;58:136–142.
DESIGN SERVICES OF

CHAPTER
Transtracheal Jet Ventilation 29 cn
Ana Maria Manrique-Espinel and Andrew Murray
Concept typical frequency of ventilation in such settings is 8 to 10

breaths per minute, allowing enough time for exhalation,
and decreasing the risk of air-trapping and barotrauma.
Handheld “jet” ventilation, using high pressure to move air
Exhalation should be confirmed by observing chest mo-
through small catheters, was conceived in the 1960s in an
tion before a subsequent tidal volume is delivered.
attempt to develop a device that would both maintain ad-
With TTJV, the FiO2 delivered is lower than 100%,
equate ventilation/oxygenation and allow surgical access
because ambient air is entrained with each pulse of high-
to the airway during endotracheal and laryngeal proce-
pressure gas. Alveolar ventilation is dependent on the
dures.1,2 Recently, this type of jet ventilation, applied via a
ventilatory rate and the effective tidal volume. Delivered
needle placed through the cricothyroid membrane (trans-
gas flow during ventilation is typically in the range of 0.5
tracheal jet ventilation, or TTJV), is one option to restore
to 1 L per second, depending upon catheter size. Because
oxygenation in the setting of an emergent difficult airway,
there is a risk of increased intrathoracic pressure with
in which neither intubation nor ventilation is possible, as
every inhalation, the inspiratory time should be limited
recommended in the American Society of Anesthesiologists
to 0.5 or 1 second. A pause between insufflations is per-
Difficult Airway Algorithm.3 Understanding this device
formed, allowing passive exit of the air secondary to the
and its application can be life saving.
recoil of the chest wall (an inspiratory to expiratory ratio
The oxygen jet stream for TTJV requires a high-
of 1:3 or 1:4 is appropriate). This methodology assumes
pressure device. This pressure can be delivered through a
a normal lung compliance (50 mL/cm H20), with a pres-
supplementary pipeline, an oxygen tank with a step-down
sure delivery system not higher than 50 psi. However, in
regulator, or an anesthesia machine. The working pressure
a lung with reduced compliance, more careful delivery of
that is necessary to achieve flow through a 14G catheter
the insufflations should be performed, with an eye toward
should be 15 psi (103 pka) at a minimum. The pipeline
avoiding dangerously high inspiratory pressures.
oxygen delivered pressure from the wall in a hospital is
There are several types of catheters available to per-
55 psi. Modern anesthesia machines provide a specific
form needle cricothyroidotomy for TTJV. Fourteen-gauge
connection for a handheld TTJV device, which provides
or sixteen-gauge intravenous-type catheters are commonly
adequate pressure for this device to function properly
used, and commercial devices are available as well, some
(Fig. 29-1).4
with reinforcement to prevent kinking (Fig. 29-3). The
Manufactured TTJV devices incorporate a pressure
VBM Manujet III (VBM medical, Noblesville, IN, USA)
regulator, which allows a variable pressure to be applied,
package includes the handheld jet ventilation device, a jet
and oxygen delivery is controlled with a handheld on/
injector and teflon catheters, in sizes 13G, 14G, and 16G,
off valve (Fig. 29-2). Several other self-assembled devices
for infants and adults. These catheters have a Luer lock to
have been adapted to connect to the handheld jet ventila-
facilitate connection to the handheld jet ventilator. In ad-
tor, though these are less reliable in delivery of adequate
dition, the distal parts of these catheters have lateral holes
ventilation than devices designed specifically for this
to decrease the venturi effect and to maintain the catheters
purpose.
far from the tracheal wall.5
The delivery of this type of jet ventilation may be per-
formed in two ways: high frequency and low frequency.
The former is typically used in intensive care units to pro-
vide very small tidal volumes for patients with poor lung Evidence
compliance (see Chapter 48). Low-frequency jet ventila-
tion through a transtracheal catheter is used in the setting TTJV was demonstrated to provide adequate ventilation
of difficult airway management, when in the “emergent in cardiac arrest patients as early as 1972, when Jacobs
pathway” of the difficult airway algorithm, necessitat- described its use in 40 cases.6 While using a high-pressure
ing immediate ventilation. The handheld jet device can oxygen source, the author was able to maintain an average
also be used for oxygenation during a bronchoscopy or PaO2 of 300 mm Hg, and a PaCO2 of 22 mm Hg with peak
a rigid laryngoscopy procedure (see Chapter 43). The airway pressures of 15 to 25 cm H2O. In 1975, Smith7
231

F IG U R E 2 9 -1 Anesthesia
machine adaptor for JET ventilator.
F IG U R E 2 9 -2 Regulator of
pressure and hand valve on–off of
the JET ventilator.
F IG U R E 2 9 -3 Transtracheal
needle.

CHAPTER 29 ■ TRANSTRACHEAL JET VENTILATION 233
described the use of TTJV in 80 patients who underwent ● Check integrity of components, test oxygen flow
airway surgery under general anesthesia. Fifty-two of these ● Prepare the neck over the cricothyroid membrane with
cases involved elective use of the technique, whereas 28 of antiseptic solution, if time allows
the patients were managed while in respiratory distress.
Several case series have shown the benefit of this technique
in patients with significant airway disease and severe glot- Procedure (Figs. 29-4–29-10)
tic narrowing, in whom tracheostomy would be difficult.8
Provided that adequate pressures are used to provide nec- ● First, the cricothyroid membrane should be identified
essary flow rates, several investigators have demonstrated (Figs. 29-4 and 29-5).
that normocarbia can be maintained while ventilating ● An angiocath needle is attached to a 10 ml syringe filled
patients with TTJV.9,10 Many of the patients described in with 5 ml of normal saline. A 14 or 16 gauge angiocath
these investigations were under general anesthesia, in con- needle (or a similar sized commercial device for crico-
trast to patients in acute respiratory failure who are fre- thyroid puncture) is attached to a 10 ml syringe filled
quently encountered in the hospital wards, intensive care with 5 ml of normal saline.
units, or emergency department. TTJV also has been useful ● The needle is advanced in a 30 degree angle to the long
in high-grade upper airway obstruction, as in the case of axis of the trachea with the tip directed caudal, continu-
a patient with a large carcinoma at the base of the tongue ously aspirating until the free aspiration of air is detected.
who sustained a respiratory arrest.11 TTJV has been used Note that the commercial needle depicted is curved, so that
effectively as a ventilation strategy in cannot intubate, can- the tip is pointing caudad into the distal airway (Fig. 29-6)
not ventilate (failed airway) situations.12–14 The technique ● The angiocath is advanced over the needle in a cau-
has also proven useful in pediatric airway emergencies.15 dad direction. The hub should be held firmly at all times
until the Luer hub is connected with the jet ventilator. Air
should be aspirated from the catheter after needle removal to
Preparation for TTJV Using ensure it is within the lumen of the airway (Fig. 29-7)
a Commercially Available ● Ventilation can then be delivered via the handheld de-
Device vice. The inspiratory time should typically be between
0.5 and 1 second (until chest rise is just appreciated)
● Preparation for direct laryngoscopy (see Chapter 5) and the inspiratory:expiratory ratio is between 1:3 and
● Anesthetized or unconscious, preoxygenated patient 1:4 (Fig. 29-8)
with head extension to allow access to cricothyroid ● Care should be taken that one person is always tasked
membrane with making sure that the catheter is stabilized at the
● Attach the high-pressure tubing of the device to 50 psi wall skin to prevent any catheter migration with possible ill-
oxygen source (or oxygen tank with two-stage regulator) effect (Fig. 29-9)
FIG U RE 29-4 Palpating the cricothyroid

membrane between the marked thyroid and
cricoid cartilages.

F I G U R E 2 9 -5 Cricothyroid membrane
demonstrated in cadaver specimen.
F I G U R E 2 9 -6 Puncture of cricothyroid
membrane.
F I G U R E 2 9 -7 Attach syringe to
catheter, pull back bubbles to reconfirm
position in airway.

● Another important point during the TTJV is to maintain fiberoptic bronchoscopic intubation may be facilitated by
the supraglotic area open to permit free exhalation TTJV (see Chapter 35).
of gas and avoid air trapping. In this regard, an oral
or nasal airway device (or both) can be used (Figs. 29-8
and 29-9) Practicality
● After this procedure, a definitive airway should be estab-
lished, such as a tracheostomy. Occasionally, the view of ● Reasonably inexpensive: ($200 to $300 for available
the glottis during direct laryngoscopy is improved dur- system)
ing TTJV, due to the high airway pressures. In addition, ● Commercial systems are portable and simple
FIG U RE 29-8 Attach TTJV system with Luer lock,

begin ventilation. Oral and nasal airways should
be in place to ensure exhalation is unimpeded, or
barotrauma may occur.
FIG U RE 29-9 An assistant should now be

designated to hold the hub of the catheter until a
definitive airway is established.

F I GURE 2 9 -1 0 If the needle is advanced

too far during puncture of the cricothyroid
membrane, perforation of the esophagus
may occur.
● Unfamiliar: user should practice hooking up compo- ● Difficult anatomy prohibiting the identification of the
nents and identifying and instrumenting cricothyroid cricothyroid membrane
membrane
Complications
Indications
● Subcutaneous emphysema
● Failed intubation and/or failed ventilation ● Pneumothorax
● Inaccessibility to oral cavity in patient requiring emergent ● Pneumomediastinum16
ventilation ● Pneumoperitoneum
● Severe facial trauma with inaccessible airway ● Dysrhythmias and gastric distension
● Severe upper airway obstruction precluding other, supra- ● Catheter displacement or kinking
glottic, emergent ventilation techniques, or failure of these ● Laryngeal or esophageal perforation (Fig. 29-10)17
techniques ● Hemodynamic changes may occur with air-trapping or
high peak inspiratory pressures, resulting in decreased
cardiac filling, hypotension, and cardiovascular collapse
Contraindications
● Bleeding diathesis
● Severe supraglottic obstruction

REFERENCES 10. Jacobs HB, Smyth NPD, Witorsch P. Transtracheal catheter

ventilation. Chest. 1974;65:36–40.
1. Jacobs HB. Emergency percutaneous transtracheal catheter 11. Biro P, Moe KS. Emergency transtracheal jet ventilation
and ventilator. J Trauma. 1972;12:50–55. in highgrade airway obstruction. J Clin Anaesth. 1975;22:
2. Jacoby JJ, Hamelberg W, Ziegler CH, et al. Transtracheal 604–606.
resuscitation. J Am Med Assoc. 1956;162:625–628. 12. Delisser EA, Muravchick S. Emergency transtracheal venti-
3. ASA Algorithm. Anesthesiology. 2003. lation. Anesthesiology. 1981;55:606–607.
4. Fassl J, Jenny U, Nikiforov S, et al. Pressures available 13. Scuderi PE, McLeskey CH, Comer PB. Emergency per-
for transtracheal jet ventilation from anesthesia machines cutaneous transtracheal ventilation during anesthesia
and wall-mounted oxygen flow meters. Anesth Analg. using readily available equipment. Anesth Analg. 1982;61:
2010;110(1):94–100. 867–870.
5. Ihra G, Gockner G, Kashanipour A, et al. High-frequency 14. Benumof JL, Scheller MS. The importance of transtracheal
jet ventilation in European and North American institu- jet ventilation in the management of the difficult airway.
tions: developments and clinical practice. Eur J Anaesthesiol. Anesthesiology. 1989;71:769–778.
2000;17(7):418–430. 15. Ravussin P, Bayer-Berger M, Monnier P, et al. Percutaneous
6. Jacobs HB. Needle catheter brings oxygen to the trachea. transtracheal ventilation for laser endoscopic procedures in
J Am Med Assoc. 1972;222:1231–1233. infants and small children with laryngeal obstruction. Can
7. Smith RB, Schaer WB, Pfaeffle H. Percutaneous transtracheal J Anaesth. 1987;34:83–86.
ventilation for anesthesia. Can J Anaesth. 1975;22:607–609. 16. Sims HS, Lertsburapa K. Pneumomediastinum and ret-
8. Ross-Anderson DJ, Ferguson C, Patel A. Transtracheal jet roperitoneal air after removal of papillomas with the
ventilation in 50 patients with severe airway compromise microdebrider and jet ventilation. J Natl Med Assoc.
and stridor. Br J Anaesth. 2011;106:140–144. 2007;99(9):1068–1070.
9. Weymuller EA, Paugh D, Pavlin EG, et al. Management of 17. Gilbert TB. Gastric rupture after inadvertent esophageal
difficult airway problems with percutaneous transtracheal intubation with a jet ventilation catheter. Anesthesiology.
jet ventilation. Ann Otol Rhinol Laryngol. 1987;96:34–37. 1998;88(2):537–538.

PART
Combination Techniques
IX
CHAPTER
Intubation through Laryngeal 30 cn
Mask Airway or Intubation

Laryngeal Mask Airway with
a Bougie, Lighted Stylet, or
Optical Stylet
Steven L. Orebaugh
fiberscope for direct visualization, in patients with in-

Concept line cervical immobilization, Asai4 reported a success
rate of 85% for the latter combination but less than
As noted in previous chapters, both the laryngeal mask 50% for the former.
airway (LMA) and the intubating laryngeal mask airway A technique that has generated more interest, and is
(ILMA) are optimally positioned when lying in the hy- likely to improve the accuracy of ETT placement, is the
popharynx, with the mask atop the glottic opening. This use of a lightwand, placed through an LMA or ILMA de-
position facilitates passage of a guiding catheter through vice, to allow the practitioner to guide an ETT into the
the tube of the device, often directly into the glottis. An larynx with transillumination. Agro et al made use of this
endotracheal tube (ETT) can then be passed over it and technique in 114 patients under anesthesia, after LMA in-
into the trachea. The LMA lumen limits the size of the sertion. After successful LMA placement, the lightwand
ETT to be passed to a size 6.0-mm internal diameter (ID) and ETT were inserted into the LMA, projecting 1.5 cm
in a size 3 or 4 LMA, or a 7.0-mm ID in a size 5 LMA. beyond the grill.5 In 78% of patients, the authors were
The 6.0 ETT can project only a short distance past the able to intubate without repositioning the LMA, whereas
mask of the LMA, into the larynx, due to the length of 10% required repositioning, and 9% required a change to
these tubes when compared with the length of the LMA different-sized LMA. Three patients were impossible to
itself. In contrast, the ILMA device, in all three sizes, has intubate in this manner.
a lumen large enough to accommodate size 8.0 ETTs. Nijima et al6 reported use of the Trachlite (Laerdahl,
Furthermore, the design of the ILMA and the push rod Long Beach, CA, USA) lightwand with the intubating LMA.
included with it facilitate removal of the device after the In their approach, the stiff internal stylet of the lightwand is
ETT is seated and confirmed to be in the airway. withdrawn, and the device is threaded through the Murphy
eye of the ETT, then its tip placed through the ILMA lu-
men. With gentle insertion of the lightwand, probing for
Evidence the glottis, transillumination was used to guide the ETT
into the larynx. Dimitriou et al evaluated the ILMA as an
Anecdotal reports exist that describe the placement of effective intubating device using a flexible lightwand in un-
a bougie through an LMA to improve the potential for expected failed laryngoscopy in 11,621 patients. The study
accurate intubation.1 However, this technique is prob- participants could not intubate a total of 44 patients with
ably no better than simply inserting an ETT through direct laryngoscopy in three attempts.7 Ventilation with the
the LMA, without guidance,2 which has a high failure ILMA was accomplished in all of these 44 patients; light-
rate.3 These blind techniques are less successful than wand-guided intubation through the ILMA was successful
those that allow visualization of the airway. In a com- in 86% on the first attempt, 12% on one or more subse-
parison of intubation through the LMA with the use of quent attempts, and failed in one patient (2%). An optical
a bougie versus the ILMA combined with the use of a stylet has also been used for intubation through the ILMA.8
239

240 PART IX ■ COMBINATION TECHNIQUES
Preparation for Lightwand- ● Observe neck for transillumination

assisted Intubation through ● Advance lightwand when transillumination indicates glot-
the LMA tic entry
● If halo of light not seen over the crycothyroid membrane
(CTM), the LMA should be repositioned, depending
● Same as for LMA insertion (see Chapter 26) on the location of visible light, by advancing, withdraw-
● Lubricate lightwand and ETT ing, or rotating it, or by placing a different size LMA (or
● Place lightwand through ETT, with tip flush with end of ILMA)
tube ● Advance lightwand/ETT until halo passes beyond CTM to
● Anesthetized or unconscious, preoxygenated patient in suprasternal notch
neutral position ● Advance ETT and remove lightwand
● Ventilate through ETT, confirm placement in airway
● Leave LMA device in place with deflated cuff (or, if using
Procedure for Lightwand- ILMA, remove it with push rod)
guided Intubation through ● Fix ETT/LMA in place
LMA (Figs. 30-1–30-3)
● Insert LMA (see Chapter 26) Practicality
● Establish optimal ventilation pattern
● Insert lightwand/ETT through lumen of LMA, to project ● Simple, portable, affordable
1.5 cm from the grill of the distal LMA lumen ● Unfamiliar: requires practice to fit lightwand/LMA
● Alternatively, insert ILMA and establish optimal ventila- through device and familiarity with transillumination of
tion, then place ETT/lightwand through lumen the larynx
F IG U R E 3 0 -1 Insertion of ETT/lightwand
into LMA situated in cadaver specimen.

CHAPTER 30 ■ INTUBATION THROUGH LARYNGEAL MASK AIRWAY 241
FIG U RE 30-2 Lightwand/ETT advanced

into airway. Note that only a few
centimeters of the 6.0 cm ETT enters the
larynx when inserted through the LMA.
● Inability to intubate trachea by direct laryngoscopy ● ETT misplacement in esophagus
● Copious blood or secretions in airway (precluding tech- ● Inability to advance lightwand/ETT
niques that require glottic visualization) ● Laryngeal or pharyngeal trauma from blind probing
● Necessity of ETT after emergency ventilation with LMA
Contraindications
● Laryngeal fracture or trauma

● Inability to ventilate through LMA
● Upper airway obstruction

F I GUR E 3 0 -3 A larger ETT may be inserted,

and to a greater depth in the larynx, when the
ILMA is used with the lightwand.
REFERENCES 5. Agro F, Brimacombe J, Carassiti M, et al. Use of a lighted

stylet for intubation via the laryngeal mask airway. Can J
1. Murdoch JAC. Emergency tracheal intubation using a Anaesth. 1998;45:556–560.
gum bougie through a laryngeal mask airway. Anesthesia. 6. Niijima K, Seto A, Aoyama K, et al. An illuminating stylet
2005;60:626–627. as an aid for tracheal intubation via the intubating laryngeal
2. Ahmed AB, Nathanson MH, Gajraj NM. Tracheal intubation mask airway. Anesth Analg. 1999;88:470–471.
through the laryngeal mask airway using a gum elas- 7. Dimitriou V, Voyagis GS, Brimacombe JR. Flexible light-
tic bougie: the effect of head position. J Clin Anesth. wand-guided tracheal intubation with the intubating
2001;13:427–429. laryngeal mask Fastrach in adults after unpredicted laryngo-
3. Benumof JL. Laryngeal mask airway and the ASA difficult scope-guided tracheal intubation. Anesthesiology. 2002;96:
airway algorithm. Anesthesiology. 1996;84:686–699. 296–299.
4. Asai T, Murao K, Tsutsumi T, et al. Ease of tracheal in- 8. Agro FE, Antonelli S, Cataldo R. Use of Shikani flexible
tubation through the intubating laryngeal mask during seeing stylet for intubation via the intubating laryngeal
manual in-line head and neck stabilization. Anesthesiology. mask airway. Can J Anaesth. 2005;52:657–658.
2000;55:82–85.

CHAPTER
Retrograde Intubation and

Flexible Fiberoptic Bronchoscope
31 cn
Intubation
Steven L. Orebaugh
Concept ● Retrieve wire from mouth, thread into suction channel at

tip of the FOB, until it emerges from suction port
● Pull end of wire out of proximal end of FOB, clamping it
Retrograde intubation (RI) was discussed in Chapter 22.
or having assistant hold it throughout the ETT insertion
Although reported success rates are high, RI remains a
● Maintain tension on wire and insert FOB along it (using
“blind” procedure: the endotracheal tube (ETT) is ad-
wire as a guide to FOB advancement)
vanced with wire guidance, and there is no visualization
● Jaw thrust and/or direct laryngoscopy will likely be re-
of the glottis as the tube is moved forward. The ETT may
quired
move out of the larynx, into the esophagus, or kink, with
● Visualize larynx, advance FOB through it, to point of wire
failure to advance, after the wire and guide catheters are
entry into larynx
removed. To improve the success of RI, it can be combined
● Advance FOB into trachea, if possible (if FOB will not
with a fiberoptic bronchoscope (FOB) in order to obtain
advance past glottis due to wire, wire can be cut and re-
direct visualization of the airway as the tube is advanced
moved to allow scope to pass)
and immediately confirm appropriate placement of the
● Carefully remove guidewire without dislodging FOB from
ETT.1,2 When the guidewire is retrieved from the mouth, it
larynx
is fed through the working channel of the FOB from distal
● Advance FOB to within sight of carina
to proximal. The FOB is then fed over the wire to the glot-
● Slide ETT over FOB, confirm position, remove FOB
tis. After the wire is removed, the FOB acts as a visualizing
● Fix ETT in place
guide catheter. This reduces the chance that the ETT will
be dislodged from the trachea during the blind technique,
as the glottis can be visualized throughout. Practicality
● Complex, unfamiliar: requires practice
Evidence ● Expensive due to use of FOB
● Not easily portable, due to FOB
Case reports attest to the use of this combination of airway ● All of the logistics issues of FOB apply (see Chapter 23)
management techniques.1–3
Indications
Preparation
● Difficult airway predicted
● Same as for RI (see Chapter 22) ● Inability to intubate, with preserved ability to ventilate
● Same as for fiberoptic bronchoscopy, except that this
combination would most likely be used in an unconscious
patient, so that topicalization is unlikely to be necessary
Contraindications
(see Chapter 23)
● Remove the rubber or plastic cover from the suction port ● Copious secretions/blood in airway
of the FOB, to allow wire to emerge from the suction ● Inability to ventilate, due to time required for this procedure
channel ● Distorted, traumatized, or unrecognizable laryngeal anatomy
Procedure (Figs. 31-1–31-5) Complications

● Carry out RI steps 1 through 5. No guide catheter is ● Complications of both RI and FOB intubation are possible
used with this combined technique (see Chapters 22 and 23)
243

F I GUR E 3 1 -1 Wire has been retrieved

from the mouth during RI in cadaver
specimen.
F I GUR E 3 1 -2 RI wire is now inserted

into suction channel of FOB.

CHAPTER 31 ■ RETROGRADE INTUBATION AND FLEXIBLE FIBEROPTIC BRONCHOSCOPE INTUBATION 245
FIG U RE 31-3 FOB is advanced over the wire,

while maintaining tension on wire.
FIG U RE 31-4 When the tip of the FOB abuts the

CTM, the wire is removed from either the CTM or
the suction port of the scope.

F I GUR E 3 1 -5 After the wire is removed,

advance the FOB distally in the trachea until the
carina is visualized. Then advance the ETT as in
any FOB-guided intubation.
REFERENCES 2. Finucane BT, Santora AH. Principles of Airway Management.

2nd ed. St. Louis, MO: Mosby; 1996:69–107.
1. Lechmann MJ, Donahoo JS, Macvaugh H. Endotracheal in- 3. Tobias R. Increased success with retrograde guide for endo-
tubation using percutaneous retrograde guidewire insertion tracheal intubation. Anesth Analg. 1983;62:366–367.
followed by antegrade fiberoptic bronchoscopy. Crit Care
Med. 1986;14:589–590.

CHAPTER

Intubation through the
32 cn
Laryngeal Mask Airway

Steven L. Orebaugh
Concept ● If difficult ventilation requires emergent LMA insertion,

then the ETT/FOB can be inserted through it during on-
going ventilation, using an FOB adaptor in the circuit:
One aspect of intubation with a fiberoptic bronchoscope the tight fit of the ETT in LMA lumen allows ventilation
(FOB) that can be frustrating is the tendency to advance through the ETT during insertion
the scope into the pharynx off of the midline, failing to ● Anesthetized, preoxygenated patient in neutral or sniffing
view the glottis and becoming “lost” in the pharyngeal position
mucosa. The laryngeal mask airway (LMA) provides an
excellent introducer for the FOB because it is usually
positioned directly atop the glottis, and whether the Procedure (Figs. 32-1–32-6)
epiglottis is held open or folded down, it facilitates pas-
sage of the tip of the scope into the airway.1 The size ● Insert LMA (see Chapter 26)
4 LMA, in both reusable and disposable versions, can ● Confirm adequate ventilation through LMA
only admit a size 6.0-mm internal diameter (ID) or (at ● After FOB is prepared, insert its tip into the proximal end
best) size 6.5-mm ID. Although such a tube is adequate
of the LMA
in diameter for ventilation of most adults, its length is ● An FOB elbow adaptor can be attached to the 15-mm
foreshortened compared with larger diameter endotra-
adaptor of the ETT, and the ETT advanced through
cheal tubes (ETTs), and it reaches only about 1 to 2 cm
the LMA to its grill; attaching a breathing circuit to the
past the vocal cords and into the larynx when passed
FOB adaptor will then allow ongoing ventilation during
through the LMA device. Therefore, long-term stability
FOB intubation attempts
of this ETT may be an issue, as even minor movement ● Advance FOB through LMA, and visualize glottis beyond
of the head or neck may dislodge it. Furthermore, it is
the grill at the end of the LMA lumen
difficult to remove the LMA without dislodging the ETT. ● Push scope tip through LMA grill, enter glottis, and
However, for short-term use, as in the operating room,
advance until carina is visualized
or for emergency ventilation followed by intubation dur- ● Advance ETT over FOB until its adaptor is flush against
ing difficult airway management in other settings, the
the adaptor of the LMA
use of the LMA to assist with FOB intubation is a valu- ● Remove FOB
able technique. ● Confirm breath sounds, ETCO2, and tube position
● Deflate cuff of LMA but do not attempt to remove
● Secure ETT/LMA in place
Evidence ● If long-term intubation is required, efforts should be made
to place a longer ETT into the trachea for improved airway
Several case reports support the value of using FOB to security (using FOB or tube changer device)
intubate through the LMA.1–4
Practicality
Preparation
● Expensive due to incorporation of FOB
● Prepare for LMA insertion (see Chapter 26) ● Neither simple nor familiar: requires training and
● Prepare for FOB intubation, using a 4-mm scope (larger practice
scopes will be difficult to insert through the 6.0 or 6.5-mm ● Portability compromised due to FOB
ID ETT) (see Chapter 23) ● All of the logistics issues of FOB apply (see Chapter 23)
247

● Difficult ventilation (LMA used initially as a lifesaving ● Complications of both LMA insertion and FOB intu-
ventilation technique, followed by FOB intubation) bation are possible with this combination technique
● Difficult intubation (LMA used as a guidance device (see Chapters 23 and 26)
for FOB)
Contraindications
● Copious blood or secretions in airway
● Inaccessibility of oral cavity (unable to insert LMA)
F I G U R E 3 2 -1 FOB inserted
through LMA into glottis in cadaver
specimen.

FIG U RE 32-2 ETT is pushed through

the mask of the LMA, into the larynx.
Because of its relatively short length, the
6.0 ETT protrudes only a limited distance
into the larynx.
FIG U RE 32-3 FOB insertion into LMA after

ventilation is optimized.

F IG U R E 3 2 -4 Introduction of
the 6.0 ETT into the LMA.
F IG U R E 3 2 -5 FOB image from inside

the LMA reveals the epiglottis, just
beyond the grill which marks the end of
the LMA lumen.
F IG U R E 3 2 -6 When the tip of the

FOB is advanced through the grill of
the LMA, the glottis is usually readily
apparent.

REFERENCES 3. Heath ML, Allagain J. Intubation through the laryngeal

mask. Anesthesiology. 1991;76:545–548.
1. Benumof JL. Use of the laryngeal mask airway to facili- 4. Orebaugh SL. Airway obstruction secondary to prolonged
tate fiberoptic bronchoscopic intubation. Anesth Analg. shoulder arthroscopy. Anesthesiology. 2003;99:1456–1458.
1992;74:313–315.
2. Benumof JL. Laryngeal mask airway and the ASA difficult
airway algorithm. Anesthesiology. 1996;84:686–699.

CHAPTER
33 Flexible Fiberoptic Bronchosope

Intubation through the Intubating
Laryngeal Mask Airway
Steven L. Orebaugh
Concept
Preparation
Just as the laryngeal mask airway (LMA) does, the intubat-
ing laryngeal mask airway (ILMA) provides an excellent
● Same as for ILMA (see Chapter 27)
conduit from the mouth to the laryngeal orifice, sitting
● Same as for FOB (see Chapter 23)
astride the glottis when properly placed. Some differences
● Slip ETT over FOB, after lubrication
between these two ventilation adjuncts exist: the steel
● The patient should be anesthetized, preoxygenated, in
barrel of the ILMA makes a right angle as it enters the neutral or sniffing position; the procedure may also be
pharynx, as opposed to the gradual curve of the standard conducted in the awake patient with topical anesthesia or
LMA lumen; the distal end of the ILMA lumen is guarded nerve blocks to anesthetize the oropharyngeal and laryn-
by an epiglottic elevating bar, rather than a grid; and the geal mucosa
barrel of the ILMA is larger than that of the standard LMA,
as it was designed to facilitate intubation of the trachea. Procedure (Figs. 33-1–33-8)
The size 3, 4, and 5 ILMA all permit intubation with an
8.0 internal diameter endotracheal tube (ETT). The pro- ● Insert ILMA (see Chapter 27)
vider may insert an ILMA and immediately choose a fiber- ● Confirm optimum position and ventilation through the
optic bronchoscope (FOB) for guided intubation or may ILMA
choose to attempt blind intubation through the device and ● Place ETT through ILMA lumen to the 15 cm band (black
call the FOB into play only if this fails. band around ETT). The tip of the ETT is now lifting the
epiglottic elevating bar, facilitating FOB passage into glottis
● Alternatively, place the FOB tip through the ILMA, past
Evidence the epiglottic elevating bar, into the airway; then advance
the ETT
The utility of intubation through the ILMA using FOB ● An FOB elbow adaptor may be attached to the 15-mm
guidance has been established through several case series ETT adaptor and a breathing circuit likewise attached to
and comparative trials. Joo1 randomized 38 patients with allow ongoing ventilation through the ETT/LMA during
known difficult airways to either awake intubation with intubation attempts
FOB or to intubation after anesthesia with ILMA. In half ● Visualize glottis; enter larynx and trachea with tip of FOB
of the latter group, the patients could not be intubated ● Advance the ETT, confirming correct placement with di-
blindly with ILMA. However, in all of these, FOB was used rect visualization through FOB
successfully to intubate through the device. Ferson2 in- ● Ventilate through ETT for further confirmation
vestigated the utility of ILMA in patients with known or ● Remove ILMA device (see Chapter 26)
suspected difficult airways (cervical immobilization; failed ● Attach circuit to ETT; reconfirm placement with breath
intubation during direct laryngoscopy; or distorted airway sounds, chest rise, and ETCO2
anatomy due to tumor, surgery, or radiation therapy). In ● Secure ETT
54 of 254 patients, FOB was chosen to guide intubation
through the ILMA device from the outset, whereas in the
other 200, blind intubation was initiated (up to 5 attempts). Practicality
The FOB was successful in 100% of the designated cases,
on the first attempt. In 7 cases selected for blind intuba- ● Complex and unfamiliar: requires practice in vitro and
tion, the ETT could not be placed in the trachea, and FOB in vivo
was used for rescue, which was also successful on the first ● Expensive (both devices)
attempt in all cases. ● Portability and logistic support are issues with FOB
(see Chapter 23)
252

CHAPTER 33 ■ FLEXIBLE FIBEROPTIC BRONCHOSOPE INTUBATION 253
FIG U RE 33-1 ILMA in appropriate position

in cadaver specimen.
FIG U RE 33-2 ILMA with FOB placed through it.

F IG U R E 3 3 -3 ETT advanced over

FOB through ILMA and into glottis.
F IG U R E 3 3 -4 Image from FOB:

glottic opening.

CHAPTER 33 ■ FLEXIBLE FIBEROPTIC BRONCHOSOPE INTUBATION 255
FIG U RE 33-5 ILMA is in place; ventilation is

confirmed.
FIG U RE 33-6 ETT is now inserted through

the ILMA, up to the 15-cm mark and just
beyond, in order to lift the epiglottic elevating
bar out of the way of FOB.
FIG U RE 33-7 FOB is inserted through ETT,

into airway, and ETT is advanced over the
scope, to an appropriate depth.

F I G U R E 3 3 -8 The scope is used

to confirm ETT position, ventilation
is also confirmed, and then the ILMA
is removed.
● Failed intubation with blind ILMA attempts ● Complications of both ILMA insertion and FOB intuba-
● Failed intubation with direct laryngoscopy tion are possible with this combination technique (see
● Failed ventilation (ILMA quickly inserted as rescue device, Chapters 23 and 27)
followed by FOB intubation with ongoing ventilation)
Contraindications
● Copious secretions or blood in airway
REFERENCES 2. Ferson DZ, Rosenblatt WH, Johansen MJ, et al. Use of the
Intubating LMA-Fastrach in 254 patients with difficult-to-
1. Joo HS, Kapoor S, Rose DK, et al. The intubating laryngeal manage airways. Anesthesiology. 2001;95:1175–1181.
mask airway after induction of general anesthesia versus
awake fiberoptic intubation in patients with difficult air-
ways. Anesth Analg. 2001;92:1342–1346.

CHAPTER

Intubation and the
34 cn
Esophago-Tracheal Combitube
Steven L. Orebaugh
Concept Procedure (Figs. 34-1–34-3)
Although the esophago-tracheal combitube (ETC) has ● Deflate oropharyngeal ETC cuff
been shown to be reliable for mechanical ventilation for ● Move the ETC to the left side of the mouth
long periods,1 the device is not suitable for ICU care, be- ● Insert FOB into oral cavity, then pharynx
cause it neither permits suctioning of the airway nor does ● Visualize the glottis, anterior to the ETC
it strictly prevent tracheal aspiration of gastric contents. ● Advance FOB into glottis, then into trachea
Furthermore, prolonged inflation of the large oropharyn- ● Slide ETT over FOB into trachea
geal balloon could potentially lead to nerve compression ● If the ETT cannot be advanced, or the glottis cannot be
in the oral cavity. A patient with difficult ventilation or visualized, the oropharyngeal balloon can be reinflated
intubation in whom an ETC is required will likely re- and ventilation temporarily resumed
quire definitive tracheal intubation for continued care ● Confirm ETT with breath sounds, ETCO2, and chest rise
in the operating room or critical care units. A fiberoptic ● Secure ETT
bronchoscope (FOB) is a viable option for ensuring safe ● Carefully remove the ETC after both cuffs are deflated
transition from supraglottic to intratracheal ventilation,
without removing the lifesaving ETC device until the en-
dotracheal tube (ETT) is securely in place. The ETC is Practicality
moved to the left side of the mouth, the oropharyngeal
balloon is deflated, and the FOB is inserted. After locat- ● Because of the use of FOB, and crowding in the pharynx
ing the glottis, the larynx and trachea are entered, and from the presence of both devices, this is neither simple
the ETT advanced. If desaturation occurs during the pro- nor familiar and requires training and practice
cedure, the oropharyngeal balloon can be quickly rein- ● FOB requires logistic support (see Chapter 23)
flated, and ventilation initiated, until oxygen saturations ● Not easily portable
once again permit a brief period of apnea.
Indications
Evidence
● Need for ETT after ETC is used for emergent ventilation
Evidence for this combination of techniques is limited to ● Inability to perform direct laryngoscopy for ETT insertion
anecdotal reports.2 with ETC in place
Preparations Contraindications
● Insert ETC (see Chapter 25) ● Copious blood or secretions in airway
● Prepare for FOB (see Chapter 23) ● Laryngeal trauma
● Lubricate ETT; load it onto scope
● Anesthetized or unconscious, preoxygenated patient in
neutral position, with ongoing ventilation via the ETC
257

F IG U R E 3 4 -1 ETC in place in cadaver

specimen.
F IG U R E 3 4 -2 Insertion of FOB into

pharynx, with oropharyngeal cuff down.

FIG U RE 34-3 FOB inserted into

larynx, with ETC in place in simula-
tion laboratory.
REFERENCES 2. Ovassapian A. Fiberoptic intubation with Combitube in

place. Anesth Analg. 1993;S315.
1. Frass M. Mechanical ventilation with the esophageal tra-
cheal Combitube in the intensive care unit. Arch Emerg Med.
1987;4:219–223.

CHAPTER
35 Transtracheal Jet Ventilation and

Intubation
Steven L. Orebaugh
Concept ● Additionally, a jaw thrust should be maintained by

assistant (in the absence of direct laryngoscopy)
● Insert FOB into pharynx
Transtracheal jet ventilation (TTJV) is rarely used, but
● Locate glottis and advance FOB into trachea
remains an important option in the cannot intubate, can-
● Avoid hitting or kinking the TTJV catheter
not ventilate patient, especially if supraglottic ventilation
● Advance ETT into airway
devices (laryngeal mask airway, esophageal-tracheal com-
● Remove FOB; confirm that ETT is in trachea
bitube, perilaryngeal airway, or laryngeal tube) have failed
● Attach circuit, confirm ETCO2, chest rise, breath sounds
or cannot be inserted. After oxygenation and ventilation
● Inflate ETT cuff
with TTJV are established, the airway nonetheless remains
● Discontinue TTJV; ventilate through ETT
unprotected. If the patient cannot rapidly be awakened to
● Remove TTJV catheter; fix ETT in place
resume spontaneous ventilation, or if this is contraindi-
● Note: this procedure can also be applied with nasal FOB,
cated, an endotracheal tube (ETT) should be placed to
if the mouth cannot be opened
guarantee patency of the airway and protect the patient
from aspiration of pharyngeal or gastric contents.
Practicality
Evidence ● Not familiar or simple: requires training and practice
in assembling components and experience with FOB in
The combination of these two techniques is supported by patients or simulators
anecdotal evidence.1,2 The pressures generated by TTJV ● Expensive due to incorporation of FOB
may serve to stent open the airway, facilitating fiberoptic ● Portability and logistics are an issue due to FOB (see
bronchoscopy (FOB), while permitting ongoing ventila- Chapter 23)
tion during the procedure.1
Indications
Preparation
● Patient with ongoing TTJV, who requires definitive airway
● Preparation for TTJV (see Chapter 29) ● Patient undergoing TTJV, who has proven to have poor
● Preparation for FOB (see Chapter 23) view at direct laryngoscopy
● Anesthetized, preoxygenated patient in neutral position, ● Predicted difficult airway
with head extension
Contraindications
Procedure (Figs. 35-1–35-4)
● Copious blood/secretions in airway
● Place catheter through cricothyroid membrane and ● Inaccessibility of oral cavity (nasal route may be chosen)
establish ventilation with TTJV (see Chapter 28) ● Other contraindications of TTJV (see Chapter 29)
● Remove oral airway, if in place (nasal airways should
remain to promote effective exhalation of air)
● Attempt direct laryngoscopy (place ETT if glottis is visible) Complications
● Assistant should continue direct laryngoscopy, to main-
tain patency of airway for expired gases, or an oral airway ● Complications of both TTJV and FOB intubation are possible
(such as Ovassapian airway) can be used to facilitate FOB with this combined technique (see Chapters 23 and 29)
260

CHAPTER 35 ■ TRANSTRACHEAL JET VENTILATION AND FLEXIBLE FIBEROPTIC BRONCHOSCOPE INTUBATION 261
FIG U RE 35-1 Ongoing TTJV simulated

in a cadaver specimen.
FIG U RE 35-2 Insertion of FOB into

larynx, taking care to avoid kinking the TTJV
catheter.

F I GU R E 3 5 -3 Advancement of ETT over

FOB and into trachea.
F I GUR E 3 5 -4 In this simulation, ongoing

TTJV is shown (note oral and nasal airway
in place to allow escape of gas) as a FOB is
used to carry out oral ETT placement.

CHAPTER 35 ■ TRANSTRACHEAL JET VENTILATION AND FLEXIBLE FIBEROPTIC BRONCHOSCOPE INTUBATION 263
REFERENCES 2. Baraka A. Transtracheal jet ventilation during fiberoptic

ventilation under general anesthesia. Anesth Analg.
1. Benumof JL, Scheller MS. The importance of transtracheal 1986;65:1091–1092.
jet ventilation in the management of the difficult airway.
Anesthesiology. 1989;71:769–778.

PART
Emergency Surgical Airways
X
CHAPTER
Cricothyrotomy 36 cn
Brian Gierl and Todd Oravitz
Concept internal aspect of the upper third of the membrane and

may cause unrecognized bleeding and aspiration.7
Cricothyrotomy is not recommended in children
Cricothyrotomy (also cricothyroidectomy or coniotomy)
under 8 years of age due to multiple anatomic differ-
is the insertion of a tracheal tube through an incision in
ences when compared with the adult airway, including
the cricothyroid membrane (CTM) in order to establish a
a hyoid bone that is more prominent than the thyroid
rapid, definitive airway. Although discouraged in the early
cartilage, cephalad CTM displacement, and a smaller
part of the 20th century because of complications, chiefly
CTM. Specifically, the dimensions of the neonate’s CTM
subglottic stenosis, cricothyrotomy was reestablished as a
is only 2.6 ⫻ 3.0 mm, making the passage of even a neo-
safe technique for airway management after publication
natal endotracheal tube (ETT) difficult, without causing
of the work by Brantigan and Grow. They documented
cartilaginous injury, edema, or hemorrhage in the airway.8
an acceptable complication rate of 6.1%, among a series
of 655 procedures.1 This compares well to the published
rate of tracheostomy complication of 6.6% for bleeding
and 5.7% for surgical site infection; these were comparable Evidence
for both a percutaneous and surgical technique.2
Cricothyrotomy is most commonly used when both Cricothyrotomy is effective for establishing an emergency
intubation and ventilation fail; in situations such as airway1 but does carry a risk of acute and chronic complica-
foreign-body obstruction; superior laryngeal trauma; in- tions. Bleeding, failure to secure the airway, and pneumo-
halation, thermal, or caustic injury to the upper airway; thorax may complicate this procedure, which is typically
angioneurotic edema; upper airway bleeding; epiglottitis carried out rapidly and often under duress. Because of its
and croup. Its use has also been advocated for patients with invasive and emergent nature, cricothyrotomy is not sub-
anatomy that would otherwise complicate tracheostomy, ject to randomization in trials of airway management, and
such as increased cervical girth, an abundance of pendu- most evidence is in the form of case series. Recent data sug-
lous, submental fat, or an entirely intrathoracic trachea in a gest that, even in the emergency department, where major
patient with restricted cervical range of motion; a small case trauma and other emergent indications for surgical airways
series of such patients did not reveal any complications.3 are likely to be higher than in other settings, the incidence
The classic technique involves a vertical midline inci- of surgical airways approximates only 1% of all intuba-
sion over the thyroid and cricoid cartilages to expose the tions.9–11 This is likely due to the success of rapid sequence
CTM, followed by a transverse incision through the CTM. intubation with direct laryngoscopy as the preferred means
The medial portion of the CTM is commonly referred to of managing the airway,9 the improved training of emer-
as the cricothyroid ligament, whereas the underlying and gency medicine residents in airway management, and the
wider membrane is known as the conus elasticus.4 The ver- lower frequency of resuscitation of blunt trauma victims
tical incision allows the operator to extend the incision in with no detectable vital signs.12 In the face of falling rates
order to obtain appropriate exposure while minimizing the of cricothyrotomy, it has become difficult to maintain pro-
risk of vascular injury. Neck veins may course within 1 cm ficiency in, and to teach, this essential skill.13
of midline in 30% of patients (Fig. 36-1), whereas midline Success rates are quite high in skilled hands, usually
arteries occur in less than 5% of patients.5 Cricothyrotomy above 90%, though these may be considerably lower when
may also be carried out with a single transverse incision carried out by inexperienced personnel.14–16 Reported
through skin and CTM, if the interval is readily palpable.1,6 acute complication rates for emergent cricothyrotomy
The incision is placed across the lower third of the CTM are between 6% and 40%.1,14–16 In Brantigan and Grow’s1
to avoid the cricothyroid artery, which transverses the landmark study, chronic subglottic stenosis did not occur
265

266 PART X ■ EMERGENCY SURGICAL AIRWAYS
after any of their 655 procedures, but in a meta-analysis ● Locate and palpate CTM
of reports from 1978 to 2008, there was a reported rate of ● Apply antiseptic solution to anterior neck
chronic subglottic stenosis of 2.2% after cricothyrotomy.17 ● Sterile draping (if time allows)
In another study, there were no long-term complications ● Anesthetized, preoxygenated patient in neutral position
among 27 patients.14 ● Subcutaneous local anesthetic if necessary (if patient is
Traditional cricothyrotomy may be complicated by not unconscious)
patient factors, including obesity, although neither patient
cervical girth nor sternomental distance correlated with the
ability of a senior otolaryngology resident’s ability to pal-
pate the cricoid cartilage.18 In one study, it was found that Procedure (Figs. 36-4–36-14)
anesthesiologists poorly identified the CTM by palpa-
tion.19 Emergency medicine physicians have developed ● Grasp thyroid cartilage firmly with long finger and
a technique that used ultrasound to quickly identify the thumb, palpating CTM with index finger of same hand
CTM and appropriate structures for cricothyrotomy.20 ● With the other hand, incise through the skin, vertically,
In the prehospital realm, Spaite21 described attempted 2 to 3 cm, from thyroid prominence to inferior border of
cricothyrotomy in 16 patients with an 88% success rate cricoid cartilage. A vertical incision can be extended to
as well as a complication rate of 31%. Boyle, in a retro- obtain adequate exposure of the CTM
spective study of cricothyrotomy by flight nurses in a ● Manually retract skin and subcutaneous tissue
teaching hospital helicopter transport program, described ● Reidentify the CTM with index finger
69 cricothyrotomy attempts among 2,108 patients trans- ● Incise horizontally, 1 to 1.5 cm through lower portion of
ported. The success rate was 98.5%, with a much lower the CTM
acute complication rate of 8.7%.22 ● *Alternatively, make a single 1.5-cm incision transversely
through the skin, subcutaneous tissue, and inferior por-
tion of the CTM, without a vertical incision if the anatomy
Preparation is well defined
(Figs. 36-2 and 36-3) ● Spread CTM with hemostat, or place a tracheal hook and
pull upward on the thyroid cartilage, allowing placement
● Prepare tools: no. 11 blade, small ETT (5.5 or 6.0 cuffed) of Trousseau dilator
and hemostat, at a minimum, or a full-fledged tracheos- ● Dilate the cricothyrotomy opening, from superior to
tomy set, with tracheostomy tube, if available. A tracheal inferior, with hemostat or dilator
hook is also desirable ● Insert ETT or tracheostomy tube between blades of di-
● Test cuff and pilot balloon of ETT or tracheostomy tube, lator or hemostat. Gentle rotation of dilator as tube is
if used. The obturator of the tracheostomy tube should be placed facilitates tube entry and advancement in a caudad
in place to facilitate insertion direction into the trachea
F I G U R E 3 6 -1 A network of
veins evident in the subcutaneous
tissue over the cricothyroid interval
(photo by David Pinkerton).

CHAPTER 36 ■ CRICOTHYROTOMY 267
FIG U RE 36-2 “Poor Man’s

Cricothyrotomy set”: a scalpel, hemostat,
and small ETT can be used to carry out
a surgical airway if a formal set is not
available.
FIG U RE 36-3 Standard tracheostomy set.
FIG U RE 36-4 Grasping the larynx while

palpating the CTM.

● Remove obturator of tracheostomy tube, inflate cuff of ● Portable

tracheostomy or ETT, ventilate, and confirm position in ● “Final common pathway” for lifesaving ventilation when
airway all else fails
● Secure tube in place with tape, sutures, or collar and ties
● Obtain chest X-ray for tube placement
Indications
Practicality
● Failure to intubate or ventilate by other methods
● Due to declining rates of surgical airways, cricothyrot- ● Facial, head, or neck trauma, when other means of intuba-
omy is unfamiliar to most: requires anatomic knowledge tion are precluded or impractical
and surgical skills; practice with animals or cadavers is ● Laryngeal trauma above the CTM
desirable ● Inaccessibility of oral cavity (if nasal intubation fails or is
● Inexpensive impractical)
F I GUR E 3 6 -5 Dissection of cadaver

specimen, revealing the strap muscles covering
the larynx and CTM.
F IG U R E 3 6 -6 Palpation of CTM.

FIG U RE 36-7 Horizontal incision in

lower portion of CTM. Vessels crossing the
membrane are more likely to be encountered
at its cephalad extent.
FIG U RE 36-8 Dilator or hemostat is used

to enlarge the incision in the CTM after
incision (a tracheal hook is helpful to pull
the thyroid cartilage upward and toward the
patient’s head, enhancing the cricothyrotomy
before the dilator is placed).
FIG U RE 36-9 Tracheal tube (ETT or

tracheostomy tube) is inserted into cricothyroid
interval.

● Severe upper airway obstruction ● Laryngeal pathology (stenosis, cancer, infection; all relative)
● Foreign-body obstruction ● Lack of familiarity with technique (relative)
● Inhalation, thermal, or caustic injury to the upper airway
● Angioneurotic edema
● Upper airway bleeding Complications
● Epiglottitis and croup
● Bleeding including blood obscuring CTM followed by
placement and cricothyrotomy failure
Contraindications ● Infection
● ETT misplacement
● Unrecognizable anatomic landmarks ● Esophageal perforation
● Coagulopathy (relative) ● Subcutaneous emphysema
● Laryngotracheal disruption with retraction of the distal ● Pneumothorax
trachea into the mediastinum ● Voice change, vocal cord injury
● Child less than 8 years of age (formal tracheostomy is ● Subglottic stenosis
preferred) ● Tracheoesophageal fistula
F I GUR E 3 6 -1 0 After confirmation of ETT

(or tracheostomy tube) position in the airway,
ventilation can begin.
F I GUR E 3 6 -1 1 Instead of a single horizontal

incision over the CTM, a midline vertical incision
can be carried out first, over the thyroid and
cricoid cartilages, as shown.
(Courtesy of Dr. Samuel Tisherman, Department
of Surgery, University of Pittsburgh School of
Medicine.)

FIG U RE 36-12 After the vertical incision,

the skin and subcutaneous tissues are retracted
and the CTM relocated with the index finger.
A horizontal incision is then made through
the CTM.
(Courtesy of Dr. Samuel Tisherman,
Department of Surgery, University of
Pittsburgh School of Medicine.)
FIG U RE 36-13 A Trousseau dilator

(or hemostat) is then used to further open the
incision through the CTM.
FIG U RE 36-14 As shown, a tracheostomy

tube, or an ETT, is inserted into the opening.

REFERENCES National Emergency Airway Registry (NEAR) II study. Ann

Emerg Med. 2000;36:S51.
1. Brantigan CO, Grow JB. Cricothyrotomy: elective use in 12. Vissers RJ, Bair AE. Surgical airway techniques. In:
respiratory problems requiring tracheostomy. J Thorac Walls RM, ed. Manual of Emergency Airway Techniques.
Cardiovasc Surg. 1976;71:72–80. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins;
2. Delaney A, Bagshaw SM, Nalos M. Percutaneous dilatational 2004:158–182.
tracheostomy versus surgical tracheostomy in critically ill 13. Chang RS, Hamilton RJ, Carter WA. Declining rate of crico-
patients: a systematic review and meta-analysis. Crit Care. thyrotomy in trauma patients with an emergency medicine
2006;10:R55. residency: implications for skills training. Acad Emerg Med.
3. Rehm CG, Wanek SM, Gagnon EB, Pearson SK, Mullins RJ. 1998;5:247–251.
Cricothyroidotomy for elective airway management in criti- 14. Isaacs JH Jr. Emergency cricothyrotomy: long-term results.
cally ill trauma patients with technically challenging neck Am Surg. 2001;67:346–349.
anatomy. Crit Care. 2002;6(6):531–535. 15. Bair AE, Filbin MR, Kulkarni RG, et al. Failed intubation in
4. Reidenbach MM. The attachments of the conuse lasticus the emergency department: analysis of prevalence, rescue
to the laryngeal skeleton: physiologic and clinical implica- techniques and personnel. J Emerg Med. 2002;23:131–140.
tions. Clin Anat. 1996;9(6):363–370. 16. Bair AE, Panacek EA, Wisner DH, et al. Cricothyrotomy:
5. Goumas P. Cricothyroidotomy and the anatomy of the cri- a five-year experience at one institution. J Emerg Med.
cothyroid space. An autopsy study. Journal of Laryngology 2003;24:151–156.
and Otology. 1997:111(4):354–356. 17. Talving P, DuBose J, Inaba K, et al. Conversion of emergent
6. Brantigan CO, Grow JB. Cricothyrotomy revisited again. cricothyrotomy to tracheotomy in trauma patients. Arch
Ear Nose Throat J. 1980;59:289–295. Surg. 2010;145(1):87–91.
7. Dover K, Howdieshell TR, Colborn GL. The dimensions 18. Hussein OF, Massick DD. Cricoid palpability as a selection
and vascular anatomy of the cricothyroid membrane: rel- criterion for bedside tracheostomy. Otolaryngol Head Neck
evance to emergent surgical airway access. Clin Anat. Surg. 2005;133:839–844.
1996:9(5):291–295. 19. Elliott DS, Baker PA, Scott MR, Birch CW, Thompson JM.
8. Navsa N, Tossel G, Boon JM. Dimensions of the neonatal Accuracy of surface landmark identification for cannula cri-
cricothyroid membrane—how feasible is a surgical crico- cothyroidotomy. Anaesthesia. 2010;65:889–894.
thyroidotomy? Pediatric Anesthesia. 2005;15(5):402–406. 20. Nicholls SE, Sweeney TW, Robinson MF, et al. Bedside
9. Sakles JC, Laurin EG, Rantapaa AA, et al. Airway manage- sonography by emergency physicians for the rapid identifi-
ment in the emergency department: a one-year study of cation of landmarks relevant to cricothyrotomy. Am J Emer
610 tracheal intubations. Ann Emerg Med. 1998;31:325–332. Med. 2008;26:852–856.
10. Tayal VS, Riggs RW, Marx JA, et al. Rapid-sequence intuba- 21. Spaite DW, Maralee J. Prehospital cricothyrotomy: an in-
tion at an emergency medicine residency: success rate and vestigation of indications, technique, complications, and
adverse events during a two-year period. Acad Emerg Med. patient outcome. Ann Emerg Med. 1990;19:279–285.
1999;6:31–37. 22. Boyle MF, Hatton D, Sheets C. Surgical cricothyrotomy
11. Walls RM, Gurr DE, Kulkarni RG, et al. 6294 Emergency performed by air ambulance flight nurses: a five-year expe-
department intubations: second report of the Ongoing rience. J Emerg Med. 1993;11:41–45.

CHAPTER
Wire-Guided Cricothyrotomy 37 cn
Adam J. Munson-Young and Ivan V. Colaizzi
Concept wire-guided method, evaluating procedural success rates

and practitioner technique preference. Nearly all (94%)
of the participants preferred the wire-guided technique
Using a concept similar to the Seldinger technique
over open crithothyrotomy, and succes of airway place-
for vessel cannulation, a wire-guided cricothyrotomy
ment was similar for both groups. Eisenburger et al4
approach can serve as a reliable and timely method for
conducted a study measuring the success and efficiency
creating access to the airway in an otherwise dire situa-
of open surgical cricothyrotomy against the wire-guided
tion. Compared with the conventional open tracheostomy
technique. No significant differences were found with
approach to establishing an airway, wire-guided cricothy-
regard to success rates, procedure time, or injury rates.
rotomy requires far less surgical skill and employs a wire-
Fikkers et al5 compared the wire-guided technique with
exchange technique that is often familiar to nonsurgical
the catheter-over-needle approach when performed by
practitioners. This method of establishing an airway in
resident physicians. No significant difference was found
an emergency situation is accomplished by puncturing
between the two groups, as successful placement of an
the cricothyroid membrane (CTM) with a thin-walled
airway occurred in 85% and 95% of the attempts, respec-
needle.1 After aspiration of air confirms the location of
tively.
the needle within the trachea, a wire is passed through
The limitations of this technique have been recog-
the needle. The needle is subsequently withdrawn, leav-
nized, making proper patient selection and positioning
ing the wire in place. A small skin incision is made over
paramount for optimizing successful completion of the
the wire, which facilitates dilation and placement of an
procedure.6 Barkhuysen et al concluded that the wire-
airway catheter into the trachea. Once inserted, the dilator
guided method for cricothyrotomy is not preferred in
is removed and the airway catheter is left seated within the
patients with severe maxillofacial trauma who rely on the
airway. This sequence, known as the Seldinger technique,
prone or sitting position with anteflexion of the neck to
has been shown to reduce insertion-related complica-
maintain patency of the airway. Wire-guided cricothyrot-
tions, including cartilagenous injury and bleeding, and to
omy has also been criticized as being more time intensive
increase rates of success for placement of an emergency
than other percutaneous approaches as there are multiple
airway.2 Commercially available kits commonly used
necessary steps for proper placement.7,8 However, emerg-
include the Melker Emergency Cricothyrotomy Kit and
ing data suggest that the technique remains both effective
Arndt Emergency Cricothyrotomy Set (Cooke Critical
and efficient.7 Metterlein et al report that compared with
Care, Bloomington, IN, USA).
a catheter-over-needle technique, wire-guided cricothy-
Other percutaneous emergency cricothyrotomy sets
rotomy carries reduced risk of posterior tracheal wall mu-
use a catheter-over-needle technique, where wire insertion
cosal injury and also enhances the opportunity for correct
is not used to facilitate airway placement. Rather, an air-
placement upon first attempt.
way is placed directly into the trachea by threading it over
a needle. Examples of these kits include the QuickTrach
(VBM Medizintechnik GmbH, Sulz am Neckar, Germany)
and the Patil Emergency Cricothyrotomy Catheter Set Preparation (Fig. 37-1)
(Cooke Critical Care, Bloomington, IN, USA).
● Same as for cricothyrotomy (see Chapter 36)
● Open kit, test-fit components (syringe, needle, wire, tra-
Evidence cheostomy tube, and obturator/dilator)
● Palpate and mark CTM
Many studies have evaluated the wire-guided tech- ● Anesthetized, or unconscious, preoxygenated patient
nique in comparison with other accepted methods of (also, the technique may be carried out in a conscious
emergently establishing an airway. Chan et al3 com- patient, with local anesthesia injected into the skin and
pared open surgical cricothyrotomy and the Melker subcutaneous tissue over the CTM)
273

F I GU R E 3 7 -1 Components of Melker
cricothyrotomy kit.
Procedure (for Melker ● Inaccessibility of oral cavity (if nasal route is not practical)
Emergency Cricothyrotomy Kit) ● Failure to intubate or ventilate by other methods
(Figs. 37-2–37-6) ● Severe upper airway obstruction that precludes use of a
supraglottic airway
● Grasp larynx firmly, holding it immobile with thumb and
long finger; identify the CTM with the tip of the index finger Contraindications
● Puncture CTM with thin-walled needle attached to a
syringe containing saline or water, aiming 45° to caudad ● Unrecognizable anatomic landmarks
● Aspirate air bubbles to confirm needle in airway ● Child less than 8 years of age (formal tracheostomy is
● Thread wire through needle
preferred)
● Remove needle ● Coagulopathy (relative)
● Use scalpel to enlarge opening around wire (some authors ● Laryngeal fracture/trauma
recommend preceding needle cannulation of CTM with a ● Lack of familiarity with the technique
1 cm, vertical incision, to facilitate dilator passage) ● Laryngeal pathology (stenosis, cancer, infection)
● Pass dilator/airway over wire into airway
● Remove dilator, inflate cuff of tracheostomy tube
● Attach breathing circuit to cricothyrotomy tube, begin Complications
ventilation
● Confirm with ETCO2, breath sounds, chest rise
● Bleeding
● Tie or suture the tube in place
● Infection
● Endotracheal tube misplacement with failed ventilation
Practicality ● Laryngeal trauma
● Esophageal perforation
● Posterior tracheal wall mucosal injury/perforation
● Inexpensive (retails for $139.00 US per kit) ● Subcutaneous emphysema
● Portable ● Pneumothorax
● Unfamiliar and complex: requires training and practice ● Subglottic stenosis
● “Final common pathway” for lifesaving ventilation when ● Voice change, vocal cord injury
all else fails ● Tracheoesophageal fistula
Indications
● Facial, head, or neck trauma, where other means of intu-
bation are precluded or impractical
DESIGN SERVICES OF

CHAPTER 37 ■ WIRE-GUIDED CRICOTHYROTOMY 275
F I GU R E 3 7 -2 Needle puncture through

the CTM.
F I GUR E 3 7 -3 After the wire is introduced,

the tracheal tube and dilator are threaded
over the wire.
F I GU R E 3 7 -4 The opening in the CTM is

enlarged with a scalpel.
DESIGN SERVICES OF

F I GURE 3 7 -5 The airway and dilator are

advanced into the airway.
F IG U R E 3 7 -6 The dilator is now

removed with the wire, and ventilation
can begin after position of the tracheal
tube in the airway is confirmed.
REFERENCES 5. Fikkers BG, van Vugt S, van der Hoeven JG, et al. Emergency
cricothyrotomy: a randomised crossover trial compar-
1. Jackson IJB, Choudhry AK, Ryan DW, et al. Minitracheotomy ing the wire-guided and catheter-over-needle techniques.
Seldinger—assessment of a new technique. Anaesthesia. Anaesthesia. 2004;59:1008–1011.
1991;46:475–477. 6. Barkhuysen R, Merkx MA, van Damme PA, et al. Acute upper
2. Melker JS, Gabrielli A. Melker cricothyrotomy kit: an alter- airway failure and mediastinal emphysema following a wire-
native to the surgical technique. Ann Otol Rhinol Laryngol. guided percutaneous cricothyrotomy in a patient with severe
2005;114(7):525–528. maxillofacial trauma. Oral Maxillofac Surg. 2008;12:35–38.
3. Chan TC, Vilke Gm, Bramwell KJ, et al. Comparison of 7. Metterlein T, Frommer M, Ginzkey C, et al. A random-
wire-guided cricothyrotomy versus standard surgical crico- ized trial comparing two cuffed emergency cricothyrotomy
thyrotomy technique. J Emerg Med. 1999;17:957–962. devices using a wire-guided and a catheter-over-needle
4. Eisenberger P, Laczika K, List M, et al. Comparison of con- technique. J Emerg Med. 2010 June 3 [Epub ahead of print].
ventional surgical versus Seldinger technique emergency 8. Schober P, Hegemann MC, Schwarter LA, et al. Emergency
cricothyrotomy performed by inexperienced clinicians. cricothyrotomy—a comparative study of different tech-
Anesthesiology. 2000;92:687–690. niques in human cadavers. Resuscitation. 2009;80:204–209.
DESIGN SERVICES OF

CHAPTER
Tracheostomy 38 cn
Nimitt J. Patel and Samuel A. Tisherman
Concept randomized trial that performing tracheostomy within

2 days of admission to ICU was associated with a reduced
occurrence of pneumonia, fewer days on the ventilator, a
Critically ill patients often require prolonged ventilator
50% reduction in the 30-day mortality rate, and a short-
support that is facilitated by tracheostomy, one of the most
ened ICU stay compared with tracheotomies performed
common surgical procedures, to replace endotracheal in-
at 2 weeks. A meta-analysis of 5 clinical trials performed
tubation.1 Tracheostomy can be performed at the bedside
with a total of 406 patients comparing early tracheostomy,
or in the operating room (OR). It can be performed open or
defined as within 7 days, versus late tracheostomy in ICU
percutaneously. The open surgical tracheostomy was first
patients showed that mortality and pneumonia rates were
described in 1909 by Chevalier Jackson. In recent years,
similar in both groups. However, early tracheostomy
the number of tracheostomies performed has increased by
significantly decreased ICU length of stay and days on
nearly 200%2; however, there is significant variability in
mechanical ventilation.7 A recent practice management
the timing and frequency of tracheostomy.3 Although the
guideline for trauma patients recommended that early tra-
need for prolonged ventilator support and better access for
cheostomy (within 3 to 7 days of admission) should be
suctioning the airway are the most common indications
performed in patients with severe traumatic brain injury
for tracheostomy, other indications include upper airway
and in patients who are likely to require mechanical ven-
obstruction, severe facial and laryngeal trauma, radical
tilation for more than 7 days.8
oropharyngeal or thyroid surgery for advanced cancer, and
Despite the potential advantages of tracheostomy,
neurologic disorders with inability to protect one’s airway.
as in any surgical procedure, there are well-documented
Patient comfort and facilitating nursing care of the airway
complications that one must consider. In a meta-analysis
may also play a role.
of 1,212 patients, some of the more common complica-
The classic open technique involves a horizontal in-
tions included bleeding (5.7%) and infection (6.6%).9
cision approximately 2 cm above the sternal notch or a
Other complications included pneumothorax, subcuta-
vertical incision extending from the inferior edge of the
neous emphysema, and esophageal perforation. One of
cricoid cartilage toward the suprasternal notch. The dis-
the most feared acute complications is accidental intra-
section is carried down to the trachea as described below
operative or postoperative decannulation with the in-
and a tracheostomy tube is usually inserted between the
ability to intubate the trachea via the oral route or re-
second and third tracheal rings. It has also become com-
cannulate the trachea secondary to an immature fistula
mon to perform tracheostomy percutaneously in the criti-
tract. Long-term complications include tracheal stenosis,
cally ill patient for prolonged ventilatory support.
tracheoesophageal fistula, and trachea-innominate fistula.
Notwithstanding these potential complications, the over-
Evidence all benefit of tracheostomy usually outweighs the risk of
the procedure.
There are many indications for tracheostomy, but the pri-
mary rationale behind performing tracheostomy is to fa- Preparation
cilitate prolonged ventilatory support in patients who fail
to wean from the ventilator.4 There is much controversy ● Prepare instruments: a standard tracheostomy set may
and conflicting evidence regarding the appropriate timing include a no. 11 or no. 15 scalpel blade, self-retaining
of a tracheostomy. Potential advantages of early tracheos- retractors, tracheal spreader and tracheal hook, nos. 6–8
tomy include decreased ventilator days, decreased length tracheostomy tubes, 10 cc syringe.
of stay in the intensive care unit (ICU), and decreased ven- ● General anesthesia is preferred for tracheostomy; how-
tilator-associated pneumonia. Studies have shown that in ever, local anesthesia with sedation is possible as well,
patients with inadequate reserve, tracheostomy decreases particularly if the airway is tenuous and induction of
work of breathing.5 Rumbak et al6 found in a prospective general anesthesia presents an undue risk to the patient.
277

Procedure (Figs. 38-1–38-8) can be checked (if available) and the chest auscultated.
Airway pressures and tidal volumes on the ventilator can
also be checked. Once the tracheostomy position is con-
● The patient is placed in a supine position with folded
firmed, the endotracheal tube can be removed
sheets or a roll under the shoulders extending the neck
● Some re-approximate the platysma and subcutaneous
for better exposure (Fig. 38-1). Sometimes this may not
tissue on either side of the tracheostomy with sutures.
be feasible secondary to neck injury or strict cervical spine
Similarly, the skin can be loosely re-approximated. The
precautions
tracheostomy tube is sutured to the skin on both sides.
● After infiltration of the subcutaneous tissues with local
A tracheostomy tie is placed around the neck to further
anesthetic solution (Fig. 38-2), a horizontal skin inci-
secure the tracheostomy tube
sion is made approximately 2 cm above the sternal notch
(Fig. 38-3). Alternatively, a vertical incision can be made
from the base of the cricoid approximately 3 to 4 cm cau- Practicality
dally, though this may be less cosmetic. The incision is
then carried through the subcutaneous tissue and pla-
tysma (Fig. 38-4). It is key to obtain hemostasis with
● Generally requires transport to OR for critically ill pa-
electrocautery tients: difficult logistics
● The strap muscles are identified and separated by making
● Expensive, primarily due to need for OR time and
a vertical incision in the midline. The strap muscles may personnel
be divided if necessary (Fig. 38-5)
● Requires extensive surgical expertise
● At this point, one frequently encounters the thyroid gland.
● Time-intensive: Generally not used in an airway
The isthmus can be divided by a serial clamping, tying, emergency
and dividing technique or by cautery to expose the tra-
chea. In some cases, the thyroid isthmus may be retracted
Indications
superiorly
● Once the trachea is exposed, the cricoid cartilage and the
first 2 to 3 tracheal rings are identified. The tracheal hook ● Prolonged ventilator support
can be inserted around the cricoid cartilage and retracted ● Improvement in pulmonary toilet
superiorly to help expose the second and third tracheal ● Upper airway obstruction
rings ● Severe airway or facial trauma
● Prior to opening the airway, the inhaled gas mixture ● Extensive head/neck surgery for cancer
should be converted to air/oxygen with an FiO2 as low as ● Risk of aspiration due to swallowing dysfunction
clinically feasible to avoid the risk of an airway fire
● Using a no. 11 or no. 15 scalpel blade, the membrane por-
tion between the second and third tracheal rings is incised
Contraindications
in a transverse fashion. Some prefer a vertical incision that
can be extended through the second or third tracheal ring. ● Emergent situation with progressive hypoxemia
Alternatively, a U-shaped incision can be made on three ● Lack of familiarity or facility with technique
sides creating a flap inferiorly, which can be secured to the ● Distorted or unrecognizable landmarks (relative)
subcutaneous tissue using an absorbable suture ● Coagulopathy (relative)
● Two sutures can also be placed on either side of the inci-
sion as stay sutures (Fig. 38-6). These can be taped to the
neck or chest in case the tracheostomy becomes dislodged Complications
in the perioperative period
● The tracheostomy tube should be lubricated and the ● Bleeding
balloon checked prior to opening the trachea ● Infection
● Once the trachea is opened, the incision is dilated using ● Extraluminal placement of tracheostomy tube
a tracheal spreader (Fig. 38-7). The endotracheal tube is ● Decannulation with loss of airway
pulled back to just proximal to the opening (never taking ● Pneumothorax
the tube out completely until the tracheostomy is placed). ● Subcutaneous emphysema
The tracheostomy tube is advanced into the airway ● Tracheal stenosis
● The ventilator can then be connected to the new tracheos- ● Tracheoesophageal fistula
tomy tube (Fig. 38-8) and end-tidal carbon dioxide level ● Tracheo-innominate artery fistula
DESIGN SERVICES OF

CHAPTER 38 ■ TRACHEOSTOMY 279
FIG U RE 38-1 Landmarks: The index finger

is on the sternal notch, head superior, and the
planned incision is between the two hemostats.
FIG U RE 38-2 Local anesthetic is infiltrated

under the skin along the planned incision.
FIG U RE 38-3 Transverse incision is made

with the thyroid cartilage held in midline.
DESIGN SERVICES OF

F I GUR E 3 8 -4 The subcutaneous tissue and

platysma are dissected using electrocautery,
and a self-retaining retractor is placed for better
visualization.
F I GUR E 3 8 -5 The platysma is divided and the

strap muscles are separated in the midline.
DESIGN SERVICES OF

CHAPTER 38 ■ TRACHEOSTOMY 281
FIG U RE 38-6 Stay sutures are placed supe-

riorly and inferiorly (as demonstrated here), or
laterally, to the planned tracheal incision for aid
in retraction and as a safety mechanism in case
the tracheostomy becomes dislodged in the
perioperative period.
FIG U RE 38-7 Tracheal spreader is used

to dilate the trachea in the direction of
the incision. The endotracheal tube can be
visualized as it is pulled back to just above the
incision to allow insertion of the tracheostomy.
It should not be completely removed until the
tracheostomy is in place.
FIG U RE 38-8 The tracheal cuff is insufflated

and the tracheostomy is connected to the
ventilator. The tube is then secured to the skin
and the stay sutures secured to the patient’s
chest.
DESIGN SERVICES OF

REFERENCES 6. Rumback MJ, Newton M, Truncale T, et al. A prospective,

randomized study comparing early percutaneous dilational
1. Durbin GC Jr. Questions answered about tracheostomy tracheotomy to prolonged translaryngeal intubation
timing? Crit Care Med. 1999;27:2024. (delayed tracheotomy) in critically ill medical patients. Crit
2. Cox CE, Carson SS, Holmes GM, et al. Increase in tracheos- Care Med. 2004;32(8):1689–1694.
tomy for prolonged mechanical ventilation in North Carolina, 7. Griffiths J, Barber VS, Morgan L, Young JD. Systematic
1993–2002. Crit Care Med. 2004;32(11):2219–2226. review and meta-analysis of studies of the timing of the
3. Nathens AB, Rivara FP, Mack CD, et al. Variations in rates tracheostomy in adult patients undergoing artificial ventila-
of tracheostomy in the critically ill trauma patients. Crit tion. BMJ. 2005;330(7502):1243.
Care Med. 2006;34(12):2919–2924. 8. Holevar M, Dunham CM, Brautigan R, et al. Practice man-
4. Heffner JE. The role of tracheostomy in weaning. Chest. agement guidelines for timing of tracheostomy: the EAST
2001;120 (Suppl. 6):477. practice management guidelines work group. J Trauma.
5. Diehl JL, El Atrous S, Touchard D, et al. Changes in 2009;67:870–874.
the work of breathing induced by tracheotomy in ven- 9. Delaney A, Bagshaw SM, Nalos M. Percutaneous dilational tra-
tilator dependent patients. Am J Respir Crit Care Med. cheostomy versus surgical tracheostomy in critically ill patients:
1999;159:383. a systematic review and meta-analysis. Crit Care. 2006;10:R55.
DESIGN SERVICES OF

CHAPTER
Percutaneous Tracheostomy 39 cn
Spencer Nabors and David Crippen
Concept performed at the bedside by intensivists. Although other

variations have been described, the Ciaglia-based tech-
niques have remained most prevalent, and when com-
Tracheostomy, as a procedure for producing secure air-
bined with bronchoscopic guidance, have been shown
way access, has been performed and refined for over
to be safe and efficacious in the hands of nonsurgeons,
4,000 years. Although historically challenged with
primarily intensivists.6
frequent complications, advances in technology and
PCT improves health delivery efficiency and clinical
minimally invasive techniques have made percutaneous
outcomes. Most importantly, early evidence suggests that
tracheostomy (PCT) a popular procedure in many inten-
PCT reduces inherent risks and operational costs involved
sive care units (ICUs). PCT is a less invasive method for
in transporting critically ill patients to the operating room
performing tracheostomy at the bedside that has become
(OR), avoiding expensive OR and anesthesia time.
a practical alternative to standard open tracheostomy in
Most of the patients for whom PCT is used are those
recent years for critically ill patients requiring prolonged
in ICUs who are slow to wean from mechanical ventila-
mechanical ventilation.
tors. Because such patients have already had an endotra-
Tracheostomy for patients who cannot be weaned
cheal tube (ETT) placed, active airway management for
from mechanical ventilation has four major benefits:
this procedure is not required, though sedation and assur-
● Increased patient comfort ance of airway patency during the procedure are neces-
● Improved pulmonary toileting sary. Some authors have described the replacement of the
● Elimination of up to 150 cc of airway dead space ETT with a laryngeal mask airway for ventilation during
● The ability to wean off and put on mechanical ventilation this procedure, in order to improve visualization of tra-
without having to reintubate endotracheally cheal structures,7 though most PCTs are performed with
the ETT still in place.
Soon after Seldinger described other needle over wire
techniques in 1953, percutaneous tracheal access was
described in 1955 by Shelden.1 Unfortunately, this first
approach of gaining access by guiding a cutting trocar into Evidence
the trachea with the use of a slotted needle resulted in unac-
ceptably high complications, as the technique for assuring Long-term complications related to classic tracheostomy
a continuous airway during the procedure was not techni- appear to be reduced with this technique. However, as
cally adequate. Since that time, the technique has been sub- with any surgical procedure, acute complications may still
stantially refined. In 1969, Toye and Weinsten2 described a occur, and the critical care physician or anesthesiologist
technique using a recessed blade and single tapered dilator taking care of ICU patients must be aware of these.8
advanced into trachea over guiding catheter. Then, in 1985, Trottier9 evaluated PCT performance prospectively
Ciaglia et al3 described the first completely percutaneous in a cohort of patients in a medical-surgical ICU, and
technique for PDT, using the Seldinger guidewire exchange described a 12.5% incidence of posterior tracheal per-
technique followed by serial dilations with sequentially foration with subsequent development of tension pneu-
larger dilators. Later, in 2000, Byhahn et al4 described the mothorax. Other authors have suggested that this is a
Ciaglia Blue Rhino, a modified Ciaglia technique using a rare complication.10,11 Wise et al12 reported the results of
single step dilation with a hydrophilically coated curved a survey sent to both trainees and established anesthe-
dilator. These methods, in their original form or in various siologists in the United Kingdom. Acute complications
hybrid forms, have proven to be convenient and effective described by this population included pneumothorax,
alternatives to traditional open surgical tracheostomy and hemorrhage, and loss of the airway or misplacement of
remain the most common method in use for PCT. the tracheostomy tube. However, a meta-analysis of stud-
In both Europe and the United States, PCT has be- ies comparing the open and percutaneous techniques
come quite popular. In a survey in Germany, Kluge et al5 described a lower frequency of postoperative bleeding
found that 86% of ICUs routinely perform PCT; 93% were and overall postoperative complications, as well as a
283

comparable frequency of overall procedural complica- ● Open the standard kit and inspect the contents (Fig. 39-1).
tions.10 More recently, Higgins and Puthakee11 conducted The operator should be familiar with each part of the kit
a meta-analysis of trials comparing the open tracheos- and its corresponding purpose. Fill the wells of the kit
tomy technique with PCT and reported no difference in with normal saline for lubrication and flush material
overall complications; there was a trend toward fewer ● Tracheostomy tube should be fitted over the appropriate
complications with PCT, including fewer wound infec- sized introducer, which should be lubricated
tions and episodes of unfavorable scarring. However, ● Bronchoscopy (optional) is performed via the indwelling
PCT appears to increase the risk of both extraluminal ETT, with attention to peak inspiratory pressures, which
placement of the tube and inability to recannulate the will rise substantially when the insertion cord of the scope
airway if decannulation occurs. Diaz-Reganon et al13 de- is placed inside the breathing circuit. The tip of the scope
scribed an incidence of early postprocedural complica- should not protrude past the end of the ETT, to avoid
tions of 0.8% and late postprocedural complications of damage to it
1.1% with this procedure.
PCT can be performed by experienced operators
without bronchoscopic guidance.14 This procedure can be Procedure (Figs. 39-2–39-11)
safely carried out on patients with coagulopathy or throm-
bocytopenia,15 in patients with cervical fractures,16 and ● Disinfect the skin and apply local anesthesia
obese patients.17 A chest X-ray is not necessarily required ● A 3 cm, transverse incision is made through the skin over
after an uncomplicated PCT procedure.18 the upper trachea, followed by blunt dissection through
soft tissue (Fig. 39-2), and the region between the first and
second or second and third tracheal rings is located19
Preparation (Fig. 39-1) ● The introducer needle, with syringe attached, is then
placed through the trachea between rings 1 and 2, or be-
● Appropriate monitoring must be ongoing during the pro- tween rings 2 and 3, aspirating as you advance the needle
cedure, as well as effective ventilation and preoxygenation (Fig. 39-3). Free air should be aspirated from the needle
with the ventilator, or with a resuscitation bag when the trachea is entered; the bronchoscope can be used
● The patient should be positioned with maximal extension to confirm intratracheal needle placement.19 Disconnect
of the neck, if this is not contraindicated the needle in order to insert the guidewire. The guidewire
F IG U R E 3 9 -1 Equipment for PCT.
DESIGN SERVICES OF

CHAPTER 39 ■ PERCUTANEOUS TRACHEOSTOMY 285
FIG U RE 39-2 After transverse skin incision,

blunt dissection is carried out down to the level
of the trachea.
FIG U RE 39-3 Needle placement in the

trachea, with air aspiration to confirm.
is then placed through the needle and should remain freely Once dilated, the hydrophilically coated dilator comes off,
mobile. Withdraw the needle while holding the guidewire leaving the white guide over the wire (Fig. 39-9)
in place (Fig. 39-4). A bronchoscope can be used to ob- ● Next, the tracheal tube, fitted on the introducer, should
serve the entry of the wire and dilators into the trachea be advanced over the guidewire and stylet into the trachea
(Fig. 39-5) (Fig. 39-10)
● The entry hole into the trachea is now dilated by sliding ● The guidewire, white stylet guide, and introducer are
a hydrophilically coated 14G dilator (or series of sequen- removed (Fig. 39-11). The cuff of the tracheal tube is
tially larger dilators) over the wire (Fig. 39-6). The white inflated and the ventilation circuit immediately attached
stylet guide and the 14G dilator (or the largest of the set ● Confirmation of ventilation by the usual means is carried
of sequentially larger dilators) are placed in one piece out, and, once confirmed, the ETT can be removed from
over the wire (Fig. 39-7). A round “stop” on the white the mouth
guide keeps the dilator from overshooting it (Fig. 39-8). ● The tracheal tube is fixed in place with tapes or sutures
DESIGN SERVICES OF

F I GUR E 3 9 -4 The guidewire has been placed

through the needle into the trachea of a
cadaver specimen.
F I GUR E 3 9 -5 Bronchoscopic guidance of

PCT during training in the anatomy lab. Here
the wire is seen within the tracheal lumen.
DESIGN SERVICES OF

FIG U RE 39-6 The white style guide, placed

over the wire, is shown in this bronchoscopic
view of the airway.
FIG U RE 39-7 The white stylet guide and

dilator are in place over the wire
FIG U RE 39-8 The round “stop” on the white

guide to prevent insertion of the dilator too far.
DESIGN SERVICES OF

F I GUR E 3 9 -9 The white guide in place over the

wire after removal of the dilator, ready to guide
insertion of the introducer and the tracheal tube.
F I GUR E 3 9 -1 0 Bronchscopic view of insertion

of the tracheostomy tube and dilator over the wire
and guide into the trachea.
F I GUR E 3 9 -1 1 After removal of the dilator,

guide catheter, and guidewire, the tracheal tube is
ready for connection to the breathing circuit and
for fixation with ties or sutures.
DESIGN SERVICES OF

Practicality Contraindications
● Relatively inexpensive compared with surgical ● Age younger than 8
tracheostomy ● Gross distortion of neck anatomy (pathology, infection,
● Logistically favorable—no requirement for transport to etc.)
OR ● Hypercarbia or hypoxemia (these are likely to get worse
● Not simple: Requires training, practice, and famil- during procedure)
iarity with procedure as well as individual kits or ● Elevated intracranial pressure
components ● Severe coagulopathy
● Requires significant time to perform—not useful as an
emergency procedure for failed ventilation
Complications19
Indications ● Elevated airway pressures with the potential for baro-
traumas
● Expected prolonged intubation during mechanical venti- ● Hypoxemia during tracheal tube placement, when ventila-
lation (including but not limited to the following clinical tion is briefly paused
situations) ● Puncture of ETT cuff with resultant difficulty in effective
● Airway obstruction ventilation
● Need for prolonged mechanical ventilation in cases of re- ● Bleeding
spiratory failure ● Damage to bronchoscope
● Need for improved pulmonary toilet ● Puncture or fracture of tracheal ring
● Prophylaxis ● Perforation of back wall of trachea or esophageal puncture
● Severe sleep apnea not amenable to continuous positive ● Persistent cuff leak from poor position or ill-fitted trache-
airway pressure devices ostomy tube
REFERENCES 10. Freeman BD, Isabella K, Lin N, et al. A meta-analysis of pro-

spective trials comparing surgical tracheostomy in critically
1. Sheldon CH, Pudenz RH, Tichy FY. Percutaneous tracheos- ill patients. Chest. 2000;118:1412–1418.
tomy. JAMA. 1957;165:2068–2070. 11. Higgins KM, Puthakee X. Meta-analysis comparison of
2. Toye FJ, Weinsten JD. A percutaneous tracheostomy device. open versus percutaneous tracheostomy. Laryngoscope.
Surgery. 1969;65:384–389. 2007;117:447–454.
3. Ciaglia P, Firsching R, Syniec C. Elective percutaneous 12. Wise H. Experience of complications of percutaneous dila-
dilatational tracheostomy. Chest. 1985;87:715–719. tational tracheostomy. Anaesthesia. 2002;57:195–197.
4. Byhahn C, Wilke HJ, Halbig S, et al. Percutaneous tracheos- 13. Diaz-Reganon G, Minambres E, Ruiz A, et al. Safety and
tomy: Ciaglia Blue Rhino versus the basic Ciaglia technique complications of percutaneous tracheostomy in a cohort of
of percutaneous dilational tracheostomy. Anesth Analg. 800 mixed ICU patients. Anaesthesia. 2008;63:1198–1203.
2000;91(4):882–886. 14. Paran H, Butnaru G, Hass I, et al. Evaluation of a modified
5. Kluge S, Baumann HJ, Maier C, et al. Tracheostomy in percutaneous tracheostomy technique without broncho-
the intensive care unit: a nationwide survey. Anesth Analg. scopic guidance. Chest. 2004;126:868–871.
2008;107:1639–1643. 15. Al Dawood, A, Haddad S, Arabi Y, et al. The safety of per-
6. Frezza EE. Open or percutaneous tracheostomy? South cutaneous tracheostomy in patients with coagulopathy or
Med J. 2008;101:229–230. thrombocytopenia. Middle East J Anesthesiol. 2007;19:37–49.
7. Linstedt U, Zenz M, Krull K, et al. Laryngeal mask airway 16. Ben Nun A, Orlovsky M, Best LA. Percutaneous tracheos-
or endotracheal tube for percutaneous dilatational tracheostomy in patients with cervical spine fracture—feasible and
tomy: a comparison of visibility of intratracheal structures. safe. Interact Cardiovasc Thorac Surg. 2006;5:427–429.
Anesth Analg. 2010;110:1076–1082. 17. Mansharamani NG, Koziel H, Garland R, et al. Safety of
8. Grant CA, Dempsey G, Harrison J, et al. Tracheo-innominate bedside percutaneous dilatational tracheostomy in obese
artery fistula after percutaneous tracheostomy: three patients in the ICU. Chest. 2000;117:1426–1429.
case reports and a clinical review. Br J Anaesth. 2006;96: 18. Kumar VM, Grant CA, Hughes MW, et al. Role of routine
127–131. chest radiography after percutaneous dilatational tracheos-
9. Trottier SJ, Hazard PB, Sakabu SA, et al. Posterior tracheal tomy. Br J Anaesth. 2008;100(5):663–666.
wall perforation during percutaneous dilatational tracheos- 19. Sarani B, Kinkle W, Reilly P. Pitfalls in percutaneous dila-
tomy: an investigation into its mechanism and prevention. tional tracheostomy using the Ciaglia one-step technique.
Chest. 1999:115;1383–1389. South Med J. 2008;101:297–302.
DESIGN SERVICES OF

PART
Pediatrics
XI
CHAPTER
Pediatric Airway Anatomy 40 cn
and Approach
Franklyn Cladis
INTRODUCTION of the oral cavity including the tongue is relaxed and

the tongue may lie against the soft palate prevent-
For the health care provider who is not experienced in in ing oral ventilation.1 Continuous positive airway
pediatrics, the pediatric airway can be challenging. The pressure, jaw thrust, and an oral airway will often
difficulty in airway management with this group of pa- relieve this obstruction. More recent evidence sug-
tients is primarily because of its differences from the adult gests that the tongue may not be the most common
airway. Understanding the anatomy and the physiology cause of airway obstruction. In an ultrasound study
of the pediatric airway can help make this landscape less by Abernethy,2 the tongue did not change position
challenging. The objective of this chapter is to provide the after the induction of anesthesia, and the authors
essentials of pediatric airway anatomy and to provide a concluded that it might not play a significant role
framework for examining this patient population. in airway obstruction. In addition, Mathru and oth-
ers3 in adults and Litman and others4 in children
demonstrated in MRI studies that the most signifi-
DEVELOPMENTAL ANATOMY cant narrowing and most likely site of upper airway
obstruction during sedation is at the soft palate and
Understanding the differences between the pediatric
the epiglottis.
and the adult airway makes the management of these
3. Position of larynx—The position of the larynx is clas-
patients less challenging and safer. These differences
sically described as being more cephalad in the new-
refer to the comparison between the neonatal airway
born than the adult. Negus5 described the location of
and the adult airway. The toddler’s airway is a transi-
the larynx at the middle of the third cervical vertebra
tion zone between the neonatal and adult. The most
in the preterm infant (C3), at the C3-4 interspace in
significant differences include the size of the pediatric
the full term infant, and at the C4-5 interspace in the
head, size of the tongue, position of the larynx, and
adult (Fig. 40-2). In an MRI study,6 the position of the
shape of the epiglottis. The narrowest portion of the pe-
hyoid bone in 15 pediatric patients aged 0 to 2 years
diatric airway is controversial but has historically been
was located at second and third cervical vertebrae
assigned to the cricoid ring.
(C2-3) compared with the third and fourth cervical
1. Head size—The neonate and infant heads are relatively vertebrae (C3-4) in the adult. The cephalad location
larger than the adult head. Because of the size of the of the larynx may make the laryngoscopic view more
occiput, when the neonate or infant is placed supine challenging because the angle from the base of the
the neck assumes a flexed position (Fig. 40-1A,B). tongue to the glottic opening is more acute. This has
They do not require any additional support behind been one reason cited for the use of straight laryn-
the head to assume the “sniffing” position. In fact, goscope blades in pediatric patients, to facilitate this
they may need a small shoulder roll to help extend view.
the head out of the flexed position and into the con- 4. Epiglottis—The size and the position of the epiglot-
ventional “sniffing” position. tis are different in the pediatric patient compared
2. Tongue—The tongue is relatively large in the neo- with the adult. The adult’s epiglottis is typically more
nate and infant compared with the adult. This may broad and rigid and is positioned more parallel to the
be a factor in airway obstruction in the anesthetized trachea. The newborn epiglottis is thinner, omega
pediatric patient. During anesthesia, the musculature shaped, and less rigid.7 Lifting the epiglottis may be
291

292 PART XI ■ PEDIATRICS
F I GUR E 4 0 -1 The large occiput in the

neonate and infant places the neck in a
natural flexion (A). Gently extending the neck
or placing a small shoulder roll will place the
head in a “sniffing” position (B).
(Courtesy of Franklyn Cladis.)
F I GUR E 4 0 -2 Position of larynx. The position of the larynx for the premature in- Glottic opening relative to
fant (7 months gestational age), full-term infant at birth, and adult. The four and half cervical vertebra (C)
month fetus has its larynx positioned even more cephalad at C2. (From Eckenhoff JE.
Some anatomic considerations of the infant larynx influencing endotracheal B a s e o f s k u ll
anesthesia. Anesthesiology. 1951;12:401–410, with permission.)
C1
C2
C3 Premature infant
Full term infant
C4
Adult
C5
DESIGN SERVICES OF

CHAPTER 40 ■ PEDIATRIC AIRWAY ANATOMY AND APPROACH 293
FIG U RE 40-3 Larynx of an infant. Note the omega-shaped

epiglottis.
Normal Edema Resistance X-sect FIG U RE 40-4 The effects of airway edema on the
R∝
1 mm 1 area resistance in the infant and the adult. The infant’s airway is
radius4 significantly more compromised by a small change in airway
diameter because of a larger increase in airway resistance
4 mm and decrease in cross-sectional area. (From Cote CJ,
Infant ↑ 16⫻ ↓ 75%
Lerman J, Todres ID. A Practice of Anesthesia for Infants
and Children. Saunders Elsevier; 2009, with permission.)
Adult 8 mm ↑ 3⫻ ↓ 44%
more difficult with a curved blade in the vallecula is inversely related to the fourth power of the radius of the
in the young child. Again, the straight blade may be lumen, any subglottic edema results in a greater change in
more effective in the pediatric patient (Fig. 40-3). airway resistance in the infant than the adult.
5. Subglottis—The cricoid cartilage has been described
as the narrowest part of the pediatric airway, compared
with the glottic opening in the adult. Recently this has
been challenged. Litman and others in 20028 found DEVELOPMENTAL PHYSIOLOGY
that the most constricted part of the larynx measured
Neonates and infants are obligate nasal breathers.11,12
on MRI in a sedated spontaneously breathing pedi-
Infants are obligate nose breathers because of their anat-
atric patient is the glottic opening and the immedi-
omy. The soft palate can contact the epiglottis. In fact,
ate subvocal cord level. Dalal and others9 confirmed
when they feed they can lock the soft palate into the epi-
this when they measured the cross-sectional area of
glottis and functionally separate their nasal breathing from
the airway with video bronchoscopy at the level of
their feeding.
the glottis and the cricoid ring in anesthetized, para-
Young children have high oral airway resistance when
lyzed pediatric patients. They found that the glottis
breathing through the mouth. However, Miller and his col-
was the narrowest part of the airway in all age groups
leagues13 demonstrated that breathing through the mouth
(6 months to 13 years) and that the airway was more
does occur in preterm infants when the nasal passage is
cylindrical than funnel shaped. Both authors also
occluded. Oral breathing is inconsistent until infants are
found that the cricoid ring is slightly elliptical.
approximately 3 to 5 months old, but Miller demonstrated
Although the glottic opening is the narrowest part of that 8% to 33% of preterm infants (31 to 36 weeks, respec-
the larynx, it is more pliable than the rigid cricoid ring. tively) will breathe through their mouth when the nose is
Therefore, it is still important to recognize that the cricoid occluded. The clinical significance is that although oral
ring may still be “the functionally narrowest portion of ventilation may occur before 3 to 5 months, it may also be
the larynx”10 and may be prone to subglottic edema and more difficult if the infant’s nasal passages are obstructed
airway compromise. Because airway resistance (Fig. 40-4) with a nasogastric tube or secretions.
DESIGN SERVICES OF

Newborns and infants also have a higher metabolic Down syndrome) (Fig. 40-5), facial asymmetry
rate and increased oxygen consumption. Neonatal oxygen (Fig. 40-6), and retrognathia (Fig. 40-7). These features
consumption is 2 to 3 times greater than that of the adult can be identified even in the uncooperative patient.
(5 to 8 vs 2 to 3 mL/kg/min).14 This is a significant cause 3. Intraoral—The intraoral examination can be very dif-
for the rapid oxygen desaturation observed during apnea ficult to achieve in the infant or young toddler but
or hypoventilation. can be facilitated by placing the child’s head in the ex-
aminer’s lap and gently using a tongue blade to look
inside the mouth.
PEDIATRIC AIRWAY EXAMINATION a. Mouth opening—How wide the child can open
his mouth should be assessed. While the mouth
The airway examination for the pediatric patient can be
is open, investigate the presence of airway/tongue
difficult because the patient may not be cooperative. An
masses, a high arched palate or a cleft palate.
infant will not open his mouth, and the toddler will often
b. Mallampati—The Mallampati classification was
hide his face. The essential features of an airway examina-
designed for adults and although it is not known
tion are outlined below.
to be reliable or valid in children, it is used in this
1. History—A history of congenital or acquired patholo- population when they are cooperative.15
gies (see Table 40-1) would suggest that a difficult c. Size of tonsils—Large tonsils may predict the
airway may be present. Also a history of difficulty presence of obstructive sleep apnea (OSA) and
with ventilation or intubation with previous anes- difficulty with mask ventilation or postoperative
thetics should be noted. airway obstruction. Pediatric patients with se-
2. Craniofacial structure—The face should be evaluated vere OSA have reduced opioid requirements.16 A
en-face (face to face) and in-profile. Attention should be grading system for tonsillar hypertrophy is pre-
paid to identifying syndromes (craniofacial anomalies, sented in Fig. 40-8.
Table 40-1
Anatomic Pathology Predicting the Difficult Pediatric Airway
(ventilation and/or intubation)
1. Choanal Atresia
CHARGE association, Apert Syndrome
2. Macroglossia
Down syndrome, Beckwith–Wiedemann syndrome, Hunter syndrome, Hurler syndrome
3. Midface hypoplasia
Apert syndrome, Crouzon syndrome, Pfeiffer syndrome, Carpenter syndrome, achondroplasia
4. Hemifacial microsomia (asymmetry)
Goldenhar syndrome
5. Retrognathia
Pierre Robin sequence, Treacher Collins syndrome, Cornelia de Lange syndrome, Smith-Lemli-Opitz
syndrome
6. Decreased neck extension
Klippel–Feil sequence, cervical spine injury or fusion, burns or contractures
7. Airway or neck masses
Tumors, abscesses
8. Infiltrative disease
Hunter syndrome, Hurler syndrome
9. Subglottic stenosis
Croup, prolonged NICU intubation
10. Facial or orthodontic hardware
Midface distractor, mandibular distractor, nasal alveolar molding
Abbreviation: NICU, neonatal intensive care unit.
DESIGN SERVICES OF

B
A
F I GUR E 4 0 -5 A: Apert syndrome—a frontal view of a child with Apert syndrome. Note the midface hypoplasia. Children with
Apert syndrome also have hand anomalies. B: Crouzon syndrome—a frontal view of a child with Crouzon syndrome. Children
with Crouzon syndrome generally do not have hand anomalies.
(Courtesy of Joseph Losee.)
FIG U RE 40-6 Facial asymmetry. The patient

has mandibular distractors in place. These will
make mask ventilation more difficult.
d. Dentition—Any loose, damaged, or missing teeth 5. Airway sounds/Auscultation—Abnormal airway sounds

should be noted. If the tooth is significantly loose can predict airway pathology. Inspiratory stridor
it may need to be removed prior to airway instru- indicates extrathoracic pathology (foreign body,
mentation. This can typically be performed after laryngomalacia, subglottic stenosis, croup, epiglot-
anesthesia has been induced. titis) biphasic stridor indicates glottic pathology, and
4. Neck extension—Any limitations of neck extension expiratory stridor or wheezing suggests intrathoracic
should be noted (see Table 40-1). Children with pathology (tracheomalacia, foreign body). A hoarse
Down syndrome may have atlantoaxial instability voice or cry suggests vocal cord pathology (vocal
although normal preoperative neck radiographs will cord palsy, vocal cord papillomas).
not predict which patients are at risk.
DESIGN SERVICES OF

F I GUR E 4 0 -7 A lateral view of an infant with

Pierre Robin Sequence. Note the hypoplastic
mandible resulting in retrognathia.
A B C
D E
F I GUR E 4 0 -8 Tonsillar grading. Zero indicates a tonsillectomy (A). Grade I tonsils are in the tonsillar fossa and are just seen
behind the anterior pillars (B). Grade II tonsils are visible behind the anterior pillars (C). Grade III tonsils are three quarters
of the way to the midline (D). Grade IV tonsils completely obstruct the airway and are known as “kissing” tonsils (E). (From
Friedman M, Tanyeri H, La Rosa M, et al. Clinical predictors of obstructive sleep apnea. Laryngoscope. 1999;109:1901–1907,
with permission.)
6. Radiography and endoscopy—CT imaging of head a. They may be more prone to airway obstruction from
and neck may be very beneficial in defining the de- the relatively large tongue and head and highly com-
gree of airway compromise from airway tumors and pliant posterior pharynx and chest wall/trachea.
abscesses. Previous endoscopies of the trachea can b. Proportionally larger pathologic changes occur and
help define preexisting pathology like laryngomala- more respiratory compromise occurs with edema/
cia, subglottic stenosis, and tracheomalacia. inflammation of the airway.
c. Infants have increased oxygen consumption com-
pared with adults.
CONCLUSION
The pediatric airway is different but NOT necessarily more
difficult to manage than that of adults. However, pediatric
patients have decreased reserve for the following reasons.
DESIGN SERVICES OF

REFERENCES 9. Dalal PG, Murray D, Messner AH, et al. Pediatric laryn-

geal dimensions: an age-based analysis. Anesth Analg.
1. Dickison AE. The normal and abnormal pediatric airway. 2009;108:1475–1479.
Recognition and management of obstruction. Clin Chest 10. Eckenhoff JE. Some anatomic considerations of the infant
Med. 1987;8:583–596. larynx influencing endotracheal anesthesia. Anesthesiology.
2. Abernethy LJ, Allan PL, Drummond GB. Ultrasound 1951;12:401–410.
assessment of the position of the tongue during induction 11. Polgar P. Airway resistance in the newborn infant. J Pediatr.
of anesthesia. Br J Anaesth. 1990;65:744–748. 1961;59:915–921.
3. Mathru M, Esch O, Lang J, et al. Magnetic resonance 12. Polgar P, Kong GP. Nasal resistance of newborn infants.
imaging of the upper airway: effects of propofol anesthesia J Pediatr. 1965;67:557–567.
and nasal continuous positive airway pressure in humans. 13. Miller MJ, Carlo WA, Strohl KP, et al. Effect of maturation
Anesthesiology. 1996;84:273–279. on oral breathing in sleeping premature infants. J Pediatr.
4. Litman RS, Weissend EE, Shibata D, et al. Developmental 1986;109:515–519.
changes of laryngeal dimensions in unparalyzed, sedated 14. Polgar G, Weng TR. The functional development of the re-
children. Anesth Analg. 2003;98:41–45. spiratory system: from the period of gestation to adulthood.
5. Negus VE. The Comparative Anatomy and Physiology of the Am Rev Respir Dis. 1979;120:625–695.
Larynx. New York, NY: Grune & Stratton; 1949. 15. Boynes SG, Moore PA, Lewis CL, et al. Complications
6. Hudgins PA, Siegel J, Jacobs I, et al. The normal pediatric associated with anesthesia administration for den-
larynx on CT and MR. AJNR Am J Neuroradiol. 1997;18: tal treatment in a special needs clinic. Spec Care Dentist.
239–245. 2010;30(1):3–7.
7. Ellis H, Feldman S, Harrop-Griffiths W. Anatomy for 16. Brown KA, Laferriere A, Moss IR. Recurrent hypoxemia
Anaesthetists. 8th ed. Oxford: Blackwell Publishing; 2003. in young children with obstructive sleep apnea is asso-
8. Litman RS, Weissend EE, Shrier DA, et al. Morphologic ciated with reduced opioid requirements for analgesia.
changes in the upper airway of children during awakening from Anesthesiology. 2004;100(4):806.
propofol administration. Anesthesiology. 2002;96:607–611.
DESIGN SERVICES OF

CHAPTER
41 Direct Laryngoscopy in Pediatrics

Jay B. Tuchman
I nfants and children are not simply miniature adults, and

their specialized anatomy and physiology significantly
impact the basic approach to pediatric laryngoscopy. As
and children without cardiovascular disease, requiring en-
dotracheal intubation for airway protection during short
surgical procedures, may be intubated without muscle
with any endeavor, and particularly in management of the relaxation, avoiding the potential adverse effects of these
pediatric airway, preparation is the key to success. The medications. Inhalational sevoflurane (6% to 8%) in oxy-
heightened emphasis on adequate preparation for airway gen is used with assisted and controlled ventilation until
instrumentation stands in reverse proportion to the age the child is motionless, apneic, and pupils are fixed, with
of the patient. This focus may be attributed to a three- careful attention to heart rate and blood pressure to avoid
fold increase in oxygen consumption, increased closing myocardial depression. Laryngoscopy can then be facili-
volumes, and consequently a predisposition to rapid oxy- tated by propofol 1 to 2 mg/kg, and spraying of the vocal
gen desaturation. As such, multiple sizes of oropharyngeal cords with 1 mg/kg of lidocaine (1% to 2%) via an atom-
and nasopharyngeal airways, laryngoscopy blades, and izing device, after achieving adequate depth of anesthe-
endotracheal tubes (ETTs) should always be immediately sia for intubation. For elective procedures during which
available (Fig. 41-1). Furthermore, when proceeding with muscle relaxation is indicated, intermediate acting non-
induction through preexisting intravenous access, ade- depolarizing muscle relaxants such as rocuronium (0.3 to
quate preoxygenation is strongly advised to help mitigate 0.5 mg/kg infant, 0.6 to 1.2 mg/kg children) or cisatracu-
desaturation during direct laryngoscopy. rium (0.1 to 0.2 mg/kg) are used to facilitate endotracheal
Optimal positioning for direct laryngoscopy depends intubation. For patients with a full stomach, requiring a
on the age of the patient and the position of the laryn- rapid-sequence intubation, the dose of rocuronium may
goscopist (sitting vs standing). In children older than age be increased to 1.2 mg/kg to achieve intubating condi-
6, positioning is similar to adults in the classic “sniffing” tions within 60 seconds in conjunction with an induction
position: elevation of the head 5 to 10 cm with a pillow agent, such as propofol (2 to 4 mg/kg), thiopental (5 to
beneath the occiput, extension of the head at the atlanto- 6 mg/kg), or ketamine (1 to 3 mg/kg). The FDA “black
occipital joint, and alignment of the oral, pharyngeal, and box” warning cautions against the use of succinylcholine
tracheal axes to facilitate laryngeal visualization. Infants, for routine pediatric airway management, due to several
however, due to their disproportionately large occiput, case reports of hyperkalemic cardiac arrests in children
do not usually require elevation of the head to adequately with undiagnosed Duchenne muscular dystrophy (mortal-
achieve anterior displacement of the cervical spine and ap- ity 55%) (Fig. 41-3). As such, the use of succinylcholine
propriate laryngeal visualization. Shoulder rolls for neona- in pediatric anesthesia is restricted to emergency intuba-
tal laryngoscopy are only beneficial when the practitioner tions, or those situations where the airway must be im-
is seated (the classic position of the otolaryngologist) and mediately secured, such as laryngospasm, difficult airway,
may actually hinder the standing practitioner (Fig. 41-2). or full-stomach precautions. The routine administration
A more beneficial position for standing neonatal intuba- of atropine (0.01 to 0.02 mg/kg) or glycopyrrolate (0.005
tion provides for an assistant holding the head in slight to 0.01 mg/kg) to prevent bradycardia and hypotension
extension, the shoulders flat on the operating room table, is now less common with the change from halothane to
with the patient placed at the level of the xiphoid process sevoflurane for standard pediatric inhalational induction.
of the intubator. When performing direct laryngoscopy, the head is held
After inhalational induction via mask and establish- in extension with the right hand while the laryngoscope
ment of an intravenous route for medication, various is inserted at the right side of the mouth. Scissoring open
pharmacologic approaches may be used to achieve appro- the mouth with one’s index finger and thumb, a technique
priate conditions for direct laryngoscopy and intubation, commonly used in adult laryngoscopy, is not performed
both with and without muscle relaxation. Most infants in infants and small children, as the small mouth opening
298

CHAPTER 41 ■ DIRECT LARYNGOSCOPY IN PEDIATRICS 299
FIG U RE 41-1 Routine equipment

for pediatric airway management.
F IG U RE 41-2 Routine positioning for seated direct

laryngoscopy in a neonate.
FIG U RE 41-3 Should this patient

receive succinylcholine? The FDA
has issued a black box warning
for routine use of succinylcholine
in pediatric intubations due to
concerns regarding hyperkalemic
cardiac arrest in patients with
undiagnosed Duchenne muscular
dystrophy.
DESIGN SERVICES OF

Table 41-1 blade, a straight blade with a curved tip, may be especially
beneficial using this method. External laryngeal pressure
Choice of pediatric laryngoscope blade may also improve the laryngoscopic view. The choice of
blade size depends on the age and BMI of the child as well
Age Blade Choice as the anesthesiologist’s preference (Table 41-1). Although
Preterm Miller 00 practices vary among practitioners, in the opinion of this
author, a stylet should be used to facilitate placement of
Neonate Miller 0
the ETT. The first attempt at intubation should use to
Neonate–2 y Miller, Phillips 1 advantage the best available equipment.
2–6 y Phillips 1, Wis-Hipple 1.5, Macintosh 1 Selection of an appropriately sized ETT depends on
6–10 y Miller 2, Phillips 2, Macintosh 2 several factors. Traditional teaching has advocated that
>10 y Miller 2-3, Phillips 2, Macintosh 2-3 only uncuffed tubes should be used in children below the
age of 8 to 10 years. Advantages cited by proponents of
the uncuffed ETT include avoidance of mucosal trauma to
the subglottis due to the presence of a leak, cricoid sealing
prevents proper insertion of the laryngoscopic blade. As (long-held belief that the cricoid cartilage is the narrowest
with adult laryngoscopy, the blade should barely touch part of the pediatric airway), and the ability to place an
the upper teeth and lip, and the upper teeth should cer- ETT of larger internal diameter. The larger ETT would
tainly never be used as a lever to pivot the laryngoscopic then allow for lower resistance to airflow (Poisseuille’s
blade. After insertion into the mouth, the blade is then law) and decreased work of breathing under spontaneous
moved toward the midline, displacing the tongue toward ventilation. The only studies supportive of the uncuffed
the left side of the mouth, advancing toward the epiglottis approach are older descriptive studies rather than com-
to expose the larynx. The blade should not be advanced parative studies. In truth, there are multiple troublesome
into the esophagus, achieving laryngeal visualization upon issues with the placement of uncuffed ETTs. Air leaks can
removal of the blade, as this technique may cause laryn- vary substantially with positioning and sedation, and pro-
geal trauma by scraping the arytenoid and aryepiglottic found changes in gas exchange may exist during mechani-
folds. In older children, a curved blade may be used with cal ventilation. Ventilation may be extremely difficult in
an approach similar to adult laryngoscopy, placing the patients with acute lung injury, with poor lung compli-
blade into the vallecula and indirectly lifting the epiglottis ance mandating increased airway pressures. Furthermore,
to expose the larynx. However, in infants and young chil- measurements of lung mechanics and tidal volume are
dren, the unique anatomical considerations described in overestimated.
the previous chapter make the straight blade laryngoscope The introduction of newer high-volume, low-pressure
a superior blade as it is more capable of elevating the base (HVLP) cuffs (the HVLP revolution) allows for lower in-
of the large pediatric tongue, facilitating laryngeal visual- flation pressures in producing a seal, with less risk of tra-
ization. The straight blade may be used in various ways. cheal trauma with prolonged intubation (Fig. 41-4). The
It may be used to directly lift the epiglottis, taking care cuffed ETT is more economical due to the use of lower
to avoid traumatizing the delicate mucosa of the airway. fresh gas flow. Cuff volumes are adjustable in sealing air
However, it may also be placed in the vallecula, similar to leaks, avoiding multiple direct laryngoscopies in deter-
a curved blade, thereby lifting the tongue and indirectly mining correct tube size. Cuff pressure must be moni-
the epiglottis, facilitating laryngeal exposure. The Phillips tored very closely with frequent gas removal, to maintain
F I G U R E 4 1 -4 Subglottic stenosis after

prolonged neonatal intubation.
DESIGN SERVICES OF

CHAPTER 41 ■ DIRECT LARYNGOSCOPY IN PEDIATRICS 301
pressures <25 cm H2O, approximating capillary pressure

of the tracheal mucosa. This in turn, avoids ischemia to the
subglottic mucosa and minimizes the incidence of postop-
erative croup. Other advantages include the reduced risk
of aspiration or airway contamination, improved EtCO2
monitoring, and reduced operating room pollution with
anesthetic gases. Studies supportive of the use of cuffed
ETT in pediatric patients include both descriptive studies
and comparative studies elucidating the previously men-
tioned advantages of cuffed ETTs.
Unfortunately, however, older designs of the pediatric
cuffed ETT including a Murphy eye at the distal shaft have
led to a multiplicity of concerns. The only mandated size
requirement for manufacturers is the internal diameter of
the ETT. Identical ETT inner diameters (IDs) may have
outer diameters that vary by as much as 0.9 mm. This is
partly responsible for the multitude of formulas to pre-
dict proper tube size. In fact, most of these formulas were FIG U RE 41-5 MRI of infant with persistent oxygen
designed for uncuffed ETT. Above the age of 2 years, the desaturation despite bilateral breath sounds revealing
most commonly used formula for determining the cor- endobronchial intubation.
rect sized ETT is (age in years ⫹ 16)/4. Details for ETT
placement in patients below the age of 2 years are listed in
Table 41-2. All of these values are for uncuffed ETT and zone as well as a cuff position guaranteed to be below the
should be downsized one half-size for cuffed ETT place- cricoid and far enough above the carina. Details for ap-
ment. One should always have available ETTs of one half- proximate insertion distances in neonates and infants are
size above and below the chosen size. listed in Table 41-3.
It should be emphasized that the use of the termi- Recent investigations have revealed that the cri-
nal phalanx of the second or fifth finger is not a reliable coid lumen is not a round structure but rather a mostly
method of estimating appropriate ETT size. When placing ellipsoid structure. This has important ramifications for
the ETT, one must remember that the length of the trachea the placement of cuffed and uncuffed ETTs. Cricoid seal-
in children below the age of 1 year may vary from 5 to 9 cm ing of an uncuffed ETT placed into the noncircular lumen
and one must be particularly mindful of the possibility of of the cricoid still exerts considerable pressure on the pos-
endobronchial intubation in the setting of small but per- terolateral wall of the cricoid, despite the air leak arising
sistent changes in oxygen saturation (Fig. 41-5). Detection from the anterior part of cricoid lumen. However, a cuffed
of EtCO2 does not confirm the lack of an endobronchial ETT with a smaller diameter placed within the distensible
intubation. Auscultation of bilateral breath sounds in the trachea allows estimation and precise adjustment of the
axillae and lung apices (not the anterior chest wall), ob- pressure exerted by the cuff on the tracheal mucosa. These
servation of symmetrical chest expansion, and, especially, investigations regarding the pediatric airway, combined
palpation of the cuff balloon in the suprasternal notch with recognition of the inadequacies of current pediatric
may be beneficial in confirming the precise location of the ETTs, have led to the development of the new Microcuff,
ETT. It is essential to place the cuff of the ETT sufficiently comprising a very short HVLP cuff at the distal shaft with
beyond the glottic opening to ensure a cuff-free subglottic improved sealing characteristics (Fig. 41-6).
Table 41-2 Table 41-3

Size of pediatric endotracheal tube Position of pediatric endotracheal tube
Age ETT Size (mm ID) Age Insertion Distance (cm)

Preterm 2.5–3.0 Preterm < 1 kg 6
Neonate–6 mo 3.0–3.5 Preterm < 2 kg 7–9
6 mo–1 y 3.5–4.0 Term newborn 10
1–2 y 4.0–5.0 1y 11
Older than 2 y (Age in years ⫹ 16)/4 2y 12
DESIGN SERVICES OF

F I GUR E 4 1 -6 Comparison of the new

Microcuff pediatric ETT to routine pediatric ETT
revealing the cuff at the distal shaft of the ETT.
REFERENCES In: Motoyama EK, Davis PJ, eds. Smith’s Anesthesia for
Infants and Children. 7th ed. St. Louis, MO: CV Mosby Co.;
Dalal PG, Murray D, Messner AH, et al. Pediatric laryngeal di- 2006: 319–358.
mensions: an age-based analysis. Anesth Analg. 2009;108: Wheeler M, Coté CJ, Todres ID. The pediatric airway. In:
1475–1479. Coté CJ, Lerman J, Todres ID, eds. A Practice of Anesthesia
Litman RS, Weissend EE, Shibata D, et al. Developmental for Infants and Children. 4th ed. Philadelphia, PA: Saunders
changes of laryngeal dimensions in unparalyzed, sedated Elsevier; 2008: 237–273.
children. Anesthesiology. 2003;98:41–45.
Motoyama EK, Gronert BJ, Fine GF. Induction of anesthesia
and maintenance of the airway in infants and children.
DESIGN SERVICES OF

CHAPTER
Adjuncts to Direct Laryngoscopy

in Pediatrics
42 cn
Jay B. Tuchman and Lawrence M. Borland
A ny approach to management of the difficult pediat-

ric airway must include both adequate preparation
and a realistic recognition that the original plan may not
posterior pharyngeal space and provide an ideal view of
the glottic opening. The flexible bronchoscope should be
kept straightened, with the tip of the scope placed in the
be successful. In this context, prior to anesthetic induc- midline. Specially designed oral airways facilitate midline
tion, it is important to have conceived of alternate plans placement during oral fiberoptic intubation, whereas nasal
for securing the airway. Persistence in repeating the same fiberoptic bronchoscopy typically allows for easier mid-
technique, without making adjustments, or changing the line placement. However, the risk of epistaxis or adenoid
approach, can induce trauma and edema within the deli- shearing is ever-present, and, hence, premedication with
cate pediatric airway and rapidly transform a situation of topical vasoconstrictors is ordinarily undertaken. The
“cannot intubate” into a more precarious scenario of “can- modified nasal trumpet can be of great assistance when
not intubate, cannot ventilate.” performing nasal fiberoptic intubation, permitting spon-
When practicing direct laryngoscopy with a standard taneous ventilation. Both volatile anesthetics and oxygen
laryngoscope, there are several maneuvers that may im- may be provided via this route (Fig. 42-3). Due to the
prove the laryngoscopic view, thus facilitating success- shorter airway distances in children, it is critically impor-
ful placement of the endotracheal tube (ETT). External tant to advance slowly through the identifiable supraglot-
pressure may be applied to the larynx, either by the laryn- tic structures of the airway, thus avoiding deep placement
goscopist or an assistant, and may be particularly help- of the fiberoptic scope in the esophagus. A pitfall of fi-
ful during infant laryngoscopy. Placing a flexible stylet beroptic-assisted intubation is resistance to advancement
inside the ETT and using a hockey-stick shape may allow of the ETT into the larynx, despite successful placement
ETT placement, even when only the epiglottis or aryte- of the fiberoptic scope. To avoid catching the ETT on the
noid cartilages are seen. The retromolar approach to di- arytenoid cartilages, one should place the ETT bevel down
rect laryngoscopy (Fig. 42-1) may be particularly useful in on the fiberoptic scope for oral intubations and bevel up
situations where routine rigid laryngoscopy is unsuccess- for nasal intubations (UNDO). One may also slightly with-
ful, such as in patients with micrognathia or macroglos- draw the orotracheal or nasotracheal tube when resistance
sia (Fig. 42-2). The head is turned slightly to the left, the is encountered, rotate 90°, and attempt again.
right corner of the mouth is retracted, and a straight blade Advantages of the flexible fiberoptic technique in-
(Miller 1 with left-handed bulb or Phillips 1) is introduced clude its adaptability to multiple difficult airway scenar-
through the right side of the mouth. The laryngoscope is ios, enabling the practitioner to secure the airway with
advanced between the tongue and lateral pharyngeal wall, minimal manipulation of the head or neck via both oral
sweeping the tongue to the left, overlying the molars, until and nasal methods. This technique is particularly ben-
the epiglottis is visualized. The lateral placement of the eficial for patients with cervical instability; syndromic
blade and movement of the head bypasses the tongue, vir- children with cervical inflexibility; and patients with
tually eliminates the need for displacement of soft tissue, temporomandibular joint (TMJ) abnormalities limiting
and improves line of site visualization. translocation and, ultimately, rotation. Improved digital
The gold standard for management of the difficult technology now allows for obtaining clearer images, even
airway remains the flexible fiberoptic bronchoscope. in the neonatal population, with the smallest scope sized
Proficiency in using this instrument remains a requisite 2.2 mm, and able to fit through a 2.5 ETT. Furthermore,
skill for every practitioner. Positioning for fiberoptic bron- light sources and video systems have been incorporated
choscopy requires slight extension of the patient’s head at into the newer bronchoscopes, allowing for increased por-
the atlanto-occipital joint, with performance of a jaw thrust tability as well as the ability to display a larger image of
by an assistant, and at times, tongue traction, to open the the airway. However, there is a significant learning curve
303

F I GUR E 4 2 -1 Retromolar technique of

pediatric laryngoscopy.
F I GURE 4 2 -2 Macroglossia in a patient

with Beckwith–Wiedemann syndrome
requiring tongue reduction.
(Courtesy of Joseph Losee MD. Department
of Pediatric Plastic Surgery at Children’s
Hospital of Pittsburgh.)
with the fiberoptic scope, and maintenance of one’s skills pathology, may be suitable choices for this approach. To
requires continuous use. Other disadvantages include the achieve successful placement, one should curve the well-
narrow field of vision allowed by the fiberoptic bundle, lubricated lighted stylet 45° to 90°, carefully maintaining
the fragility and expense of the scopes, and the need for the tip of the stylet within the tip of the ETT to avoid
frequent cleaning and maintenance of the equipment. airway trauma. Dimming the room lights may be particu-
Excessive secretions or blood may render the scope unus- larly helpful with this approach. The stylet is passed along
able, particularly when using the neonatal scope, which the curvature of the tongue until a clearly circumscribed
lacks a channel for suctioning or administering local circular light transilluminates the middle of the neck. The
anesthetic. ETT is then gently advanced off the stylet into the trachea.
A pediatric lighted stylet (“light wand”), equipped The most common difficulty in using this technique is that
with a high-intensity light at the tip, may also be used the ETT catches on the epiglottis. This may be corrected
to secure the difficult pediatric airway and is particularly by withdrawing the stylet and placing it more posteriorly,
helpful in patients with cervical spine fractures, due to allowing placement of the ETT underneath the epiglottis,
the ability to achieve intubation without neck movement. or by rotating the bevel of the ETT. Drawbacks to this
Patients with micrognathia (Fig. 42-4) or TMJ disease, in technique include the possible risk of bleeding, secondary
whom there is a concern regarding laryngoscopic view, to blind insertion of the stylet. Use of the lighted stylet is
yet without any intrinsic laryngeal or oropharyngeal also restricted to larger children and insertion of larger
DESIGN SERVICES OF

CHAPTER 42 ■ ADJUNCTS TO DIRECT LARYNGOSCOPY IN PEDIATRICS 305
FIG U RE 42-3 Modified nasal airway for

pediatric nasal flexible fiberoptic bronchoscopy.
FIG U RE 42-4 Micrognathia in a patient with

Pierre Robin sequence.
(Courtesy of Joseph Losee MD. Department of
Pediatric Plastic Surgery at Children’s Hospital of
Pittsburgh.)
ETTs, due to the large diameter of the stylet. The lighted may be used for oral intubation, does not require neck
stylet may also be less successful in obese patients and extension, and offers the advantage of displacing soft tissue
should not be used to secure the airway in the presence and enabling oxygen delivery during intubation attempts.
of airway tumors, laryngeal injuries, and retropharyngeal Most often, direct laryngoscopy is performed prior to in-
abscesses. sertion of the device. As with other fiberoptic techniques,
The Shikani optical stylet is a rigid, yet malleable this device requires a significant learning curve, may be
metal stylet with a fiberoptic light source, which deliv- quite fragile, and may be rendered ineffective by fogging,
ers an image to an eyepiece or video camera. This device blood, and secretions. A benefit of the optical stylet over
DESIGN SERVICES OF

flexible fiberoptic laryngoscopy is the ability to visualize for different ages of children, as well as a warming device
the tip of the ETT as it passes into the trachea. at the tip of the blade to reduce fogging. The Storz video
The first indirect laryngoscope using fiberoptic tech- laryngoscope can be used for direct laryngoscopy and con-
nology, the Bullard (Circon, Stamford, CT, USA), was verted to video laryngoscopy, a particularly useful tool in
originally designed for use in the difficult pediatric airway. the suspected, but unconfirmed, difficult pediatric airway.
The device is particularly beneficial in patients without The Airtraq is also available in several sizes and has a lens
neck extension and should be positioned like a laryngos- warmer to prevent fogging, but requires warmup time for
copy blade within the larynx, using a 90° bend to pro- this mechanism to work. The particular advantage of this
vide improved visualization around the base of the tongue device is its portability and one-time disposable use, mak-
in syndromic patients with mandibular hypoplasia. The ing it well suited for non operating room use. The Truview
styletted ETT, with a similar curve as the Bullard laryn- EVO2 provides a wide-angle magnified view and provides
goscope, is advanced into the trachea under direct visu- an infant blade with a port for oxygen insufflation.
alization after achieving an adequate laryngeal view. The Perhaps the most versatile approach for the difficult
method of visualization with this device is vastly different pediatric airway is the use of the laryngeal mask airway
than standard laryngoscopy and thus requires a significant (LMA) as a conduit for insertion of the ETT. The LMA
learning curve to achieve consistent success. may serve as an adjunct for ventilation, while attempts to
A multitude of new video laryngoscopes has been de- secure the airway via intubation are in process. Although
signed for use in children, including those with camera inte- blind intubation may be accomplished via the classic LMA,
gration into the laryngoscope blade, such as the GlideScope as the distal opening of the LMA is often at the glottis, the
Cobalt (Verathon, Bothwell, WA, USA) and Storz video most successful method for LMA-guided intubation in chil-
laryngoscope (Karl Storz, Tuttlingen, Germany), as well dren uses the flexible fiberoptic scope to advance the ETT
as those using prisms and mirrors, such as the Airtraq op- through the LMA. An important limitation of this approach
tical laryngoscope (Prodol Meditec, Vizcaya, Spain) and in the infant population is the inability to pass the pilot
Truview EVO2 (Truphatek International, Netanya, Israel). balloon of a cuffed ETT through the LMA. One choice is to
All of these devices permit the head and neck to remain in place an uncuffed ETT and use another ETT as a “pusher”
a neutral position, may be used as teaching tools, and share when removing the LMA. However, the great advantages
the advantage of bearing a certain similarity to intubation of placing a cuffed ETT in this patient population have al-
with a standard laryngoscope. However, video laryngos- ready been described in detail in the previous chapter. To
copy still requires coordination of the practitioner’s focus avoid the need for placement of an uncuffed ETT, with sub-
on the video monitor with the manual dexterity of his or sequent cumbersome cuffed ETT exchange and associated
her hands. All of these devices require at least some mouth risk of extubation, one can cut the pilot balloon to facilitate
opening to pass the device, and may be complicated by placement of the cuffed ETT and then reconstruct the pilot
fogging, blood, and secretions. Airway trauma may occur balloon (Fig. 42-5). This may be done by inserting an IV
as a result of blind passage of a styletted ETT into the oro- catheter into the cut end of the tubing, removing the nee-
pharynx, and most importantly, a good laryngeal view does dle, and attaching a one-way Luer lock valve port adapter
not guarantee ease of ETT placement. Each of these new to the end of the IV catheter. Another approach, using the
videolaryngoscopy devices has its own particular advan- specialized Air-Q LMA, facilitates placement of a cuffed
tage. The GlideScope Cobalt has multiple sizes of blades ETT by employing a flexible fiberoptic scope, without the
F I GUR E 4 2 -5 Reconstruction of the pilot

balloon after LMA-guided fiberoptic intubation
with a cuffed ETT.
DESIGN SERVICES OF

CHAPTER 42 ■ ADJUNCTS TO DIRECT LARYNGOSCOPY IN PEDIATRICS 307
FIG U RE 42-6 Comparison of the wider and

shorter shaft of the new Air-Q LMA with the
classic LMA facilitating LMA-guided flexible
fiberoptic intubation.
need for dismantling the pilot balloon. The airway tube REFERENCES
of the Air-Q is wider and shorter than the standard LMA,
accommodating the pilot balloon and minimizing the risk Fiadjoe J, Stricker P. Pediatric difficult airway management:
of accidentally pulling the ETT when removing the LMA current devices and techniques. Anesthesiol Clin. 2009;27:
185–195.
(Fig. 42-6). There is a stabilizer bar provided by the manu-
Motoyama EK, Gronert BJ, Fine GV. Induction of anesthesia
facturer, which wedges inside the ETT, allowing successful
and maintenance of the airway in infants and children.
removal of the LMA without catastrophic removal of the In: Motoyama EK, Davis PJ, eds. Smith’s Anesthesia for
ETT, after securing the difficult airway. Infants and Children. 7th ed. St. Louis, MO: CV Mosby Co.;
In conclusion, recent technological advances have 2006:319–358.
widened the array of tools, and consequently approaches, Walker RWM, Ellwood J. The management of difficult intuba-
available in the pediatric anesthesiologist’s armamentar- tion in children. Paediatr Anaesth. 2009;19:77–87.
ium. Each practitioner should become comfortable with Wheeler M, Coté CJ, Todres, ID. The pediatric airway. In: Coté
a few of these techniques in the normal pediatric airway, CJ, Lerman J, Todres ID. A Practice of Anesthesia for Infants
thereby facilitating management when faced with the truly and Children. 4th ed. Philadelphia, PA: Saunders Elsevier;
difficult pediatric airway. 2008:237–273.
DESIGN SERVICES OF

PART
Bronchoscopy
XII
CHAPTER
Rigid Bronchoscopy 43 cn
Peter Ferson
INTRODUCTION BRONCHOSCOPE
The application of endoscopic methods to evaluate and The rigid bronchoscope is a hollow tube, with a fiberoptic
treat disorders of the airways is an essential skill for the light source usually conveyed to the distal end. The distal
clinician who practices anesthesiology, thoracic surgery, end is beveled to facilitate insertion and maneuvering in the
pulmonary medicine, or otolaryngology. As with most fac- airway. There are side openings in the distal end to permit
ets of practice, endoscopic technology is constantly chang- ventilation of the contralateral bronchus, when the scope is
ing. The clinician must, therefore, be aware not only of introduced into a distal bronchus. The tubes come in vari-
the historical development of techniques, but also of cur- ous diameters and lengths. Proximally there is an opening
rently available methods and instrumentation, so that he for viewing and working. Viewing is enhanced by inserting a
may properly select the appropriate equipment and use it telescope and camera through the tube. The proximal open-
effectively. ing may be occluded with a window plug if a closed system
is desired, or to prevent backflow of contaminated material.
There is a side port for attaching a ventilation circuit and a
HISTORY smaller port for connecting a jet ventilator (Fig. 43-1).
Although ancient physicians from Greece and the Middle
East clearly made efforts to peer into body orifices using PATIENT SELECTION
specula, Bozzini seems to have been the first to create a
device specifically designed to direct light into a cavity. He There are several indications for considering rigid bron-
described his lichleiter in 1806. This used a wax candle as choscopy. This method is clearly more effective than flex-
a light source and a mirror directing the light into the vari- ible bronchoscopy in clearing thick inspissated secretions
ous parts of the body so that he could examine through a or blood. When confronted with significant bronchial
lens. He is reported to have performed vaginal, rectal, and bleeding, clearing the blood, packing off the offending
pharyngeal examinations with this instrument.1–3 The bronchus (with hemostatic gauze), and ventilating the con-
first clear use of an endoscopic technique to examine the tralateral lung requires rigid bronchoscopy. Many foreign
airway was by Gustav Killian in 1897. For his initial ef- bodies can be removed by flexible bronchoscopy, but the
forts, he hired a paid volunteer but later successfully re- more troublesome ones that are elusive, large, or impacted
moved a foreign body from the airway.4 The use of various can be best dealt with by rigid bronchoscopy. Obstructing
tubes, light sources, and lens systems flourished in the tumors in the trachea and mainstem can be debrided more
early half of the 20th century. A major contributor in the expeditiously with a rigid bronchoscope, and flexible laser
United States to the development of the techniques and bronchoscopy can be performed through a rigid broncho-
devices was Chevalier Jackson who practiced bronchoscope to combine the advantages of each technique. The
esophagology in Pittsburgh and Philadelphia. He is widely indications for rigid bronchoscopy are listed in Table 43-1.
considered to be the father of American otolaryngology.5
In 1968, Ikeda6 first reported on the use of the flexible INSERTION TECHNIQUE
fiberoptic bronchoscope. The ease of use and patient com-
fort with this device allowed it to quickly overshadow the Insertion of a rigid bronchoscope should be accompa-
rigid bronchoscope for the purpose of examination of the nied by an initial examination of the facial anatomy and
airways. the upper airway, as one would perform for standard
309

310 PART XII ■ BRONCHOSCOPY
F I GUR E 4 3 -1 A: Tip of a bronchoscope. The

ventilation side ports permit aeration of the
contralateral bronchus when the tip of the scope is
impacted in the bronchus being examined.
The beveled end of the bronchoscope facilitates
passage through the larynx, past the carina, and
into the distal mainstem bronchi. B: Bronchoscopes
are available in various diameters and lengths. Inner
diameters range from 3 (not shown) to 8.5 mm.
Maintenance of a complete set of sizes is vitally
important in a facility in which procedures
are performed on both children and adults.
C: The working end of the rigid bronchoscope has
connections for a ventilator adaptor, a jet
ventilation port, a window plug to occlude the
working channel if desired, and a light connector
for the fiberoptic light cord (not shown).
(Reused with permission from Ferson PF, Eibling DE.
Bronchoscopy and tracheoscopy. In: Myers EN, ed. A
Operative Otolaryngology: Head and Neck Surgery.
2nd ed. Philadelphia, PA: Elsevier/WB Saunders;
2008.)

CHAPTER 43 ■ RIGID BRONCHOSCOPY 311
Table 43-1 the tongue anteriorly until the uvula is identified, and
then lifting the tongue and mandible to identify the
Indications for Rigid Bronchoscopy tip of the epiglottis. The leading edge of the broncho-
scope is passed under the epiglottis and then rotated
Examination of the upper airway
90° so that the sharp vertical axis of the bronchoscope
Obtaining large biopsies is oriented anterior to posteriorly. While support-
Removal of thick secretions ing the bronchoscope on the mandible or upper teeth,
Control of significant bleeding with the left fingers on the teeth and the thumb sup-
Extraction of foreign bodies porting the bronchoscope, the edge is advanced between
Evaluation and dilation of strictures the vocal cords so that the left vocal cord is visualized
and the right vocal cord is displaced laterally. The head
Endobronchial debridement of tumor
will often need to be lifted into an exaggerated sniffing
Stent placement position to accomplish this with the rigid bronchoscope.
Once the tip is through the larynx the head can be low-
ered to allow the scope to match the axis of the trachea.
endotracheal intubation. The ideal patient for rigid When the tip has entered the larynx, ventilation may be
bronchoscopy is thin and edentulous, with a long sup- established (Fig. 43-2).
ple neck and a generous mouth opening. Such a patient The alternative method of introducing the rigid bron-
is rare. Features such as prominent teeth, small mouth choscope is preferred by the author. For this method, a
with a receding chin, and cervical fixation or kyphotic laryngoscope is used. A Macintosh blade is ideal because a
posture, all contribute to making the procedure more Miller blade would cause “sword fighting” along the same
difficult and thus more hazardous. Although none of axis as the bronchoscope. Using a Macintosh blade, the
these features will be an absolute contraindication to airway is exposed holding the blade with the left hand and
performing rigid bronchoscopy, the endoscopist must inserting the bronchoscope with the right hand again turn-
carefully weigh the risks presented by patient anatomy ing it 90° so that the vertical edge is in the same orientation
before proceeding. as the opening between the vocal cords. As the broncho-
Although topical anesthesia and sedation have been scope is passed through the larynx, the laryngoscope is
used for rigid bronchoscopy, in most instances general removed and the left hand is used to support the broncho-
anesthesia is appropriate. Induction should proceed as for scope on the teeth or maxilla. Occasionally, with an ante-
standard intubation. The patient may be first intubated rior airway only the arytenoids can be seen through the
with an endotracheal tube to have the airway controlled, rigid bronchoscope until the laryngoscope is removed and
and then once stabilized, the table should be turned the left hand is used to direct the tip upwards and into the
90° with the anesthesiologist now at the patient’s left and larynx. From this point, in both methods the procedure
the endoscopist sitting at the head of the table above the continues in a similar fashion, examining the airways, the
patient. Monitoring with a pulse oximeter is appropriate; trachea, and the mainstem bronchi as need be (Fig. 43-3).
rarely is an arterial line necessary. If the patient is intu-
bated, the endotracheal tube is withdrawn and the bron-
choscope inserted in the described fashion. Ventilation is VENTILATION
established by a jet ventilator directly through the bron-
choscope or by intermittent positive pressure ventilation Ventilation during rigid bronchoscopy can be performed
with a closed system including a window plug. with standard positive pressure ventilation although
It is not necessary to have an endotracheal tube placed usually with a significant air loss and with intermittent
initially, particularly if the endoscopist is comfortable with apnea. The preferred alternative is to use sustained jet ven-
the technique of introducing the bronchoscope. With this tilation. The jet ventilation may be accomplished with a
method the bed is turned 90° before induction, and the manual jet trigger, but a dedicated jet ventilator facilitates
endoscopist holds the ventilating mask with an appropri- smoother control of ventilation. The typical initial settings
ate mouthpiece until the patient is fully anesthetized, and for a mechanical jet ventilator would be a frequency of 100
the larynx is then intubated with the bronchoscope as one to 125 pulses per min with a driving pressure of 25 mm
would perform with the endotracheal tube. If there is no Hg (see Chapter 48). These settings may be adjusted for
question about the integrity or the exposure of the airway chest size and for adequate oxygenation. When using jet
then muscle relaxation is undertaken prior to inserting the ventilation, it is essential to keep an open circuit. There
rigid bronchoscope. is a natural tendency for those unfamiliar with this tech-
There are two methods that are appropriate for the nique to place an occlusive window plug and to obstruct
introduction of the bronchoscope into the airway. In the the outflow. This will result in increasing airway pressure
first, the bronchoscope is used as a laryngoscope, being and, ultimately, alveolar rupture. Also, with prolonged jet
inserted between the palate and the tongue, depressing ventilation, there is a risk of elevated CO2 levels, which

B A B
A B
A B
C D
F I GUR E 4 3 -2 A: Technique of intubation. The bronchoscope is aligned in the midline of the tongue while the mouth is held
open with the thumb and fingers. The bronchoscope is supported with the thumb, and the uvula (A) and epiglottis (B) are
visualized to maintain midline orientation. B: The bronchoscope is advanced while aiming behind the epiglottis, and the larynx
is visualized. C: With the tip of the bronchoscope behind the epiglottis, the initial view (A) will show both the right and the left
vocal cords. This is not the correct position to advance the bronchoscope into the trachea. The bronchoscope is rotated 90°
clockwise so that the leading tip of the beveled end is to the right lateral side. The entire bronchoscope is shifted laterally to
expose the left vocal cord (B). With this exposure and this orientation, the bronchoscope may be advanced safely into the
trachea without causing trauma to the right vocal cord. The left vocal cord will slide along the bevel and be pushed laterally as
the bronchoscope enters the trachea. D: The bronchoscope has been advanced past the larynx into the trachea for distal tracheal
examination. It is important at this point that the upper hand be placed in a firm position to protect the teeth and upper jaw
from pressure from the bronchoscope. The bronchoscope should rest on the left thumb and not against the teeth; this is a
position similar to an open bridge, as used with a cue stick for shooting billiards.
(Adapted with permission from Ferson PF, Eibling DE. Bronchoscopy and tracheoscopy. In: Myers EN, ed. Operative
Otolaryngology: Head and Neck Surgery. 2nd ed. Philadelphia, PA: Elsevier/WB Saunders; 2008.)
may require standard intubation, and hyper-ventilation to around the bronchoscope tube. Once full oxygenation has
correct. been reached, discontinuing the positive pressure and
For prolonged procedures, when hypoxia develops resuming jet ventilation will allow for continued working
during jet ventilation, attaching the anesthesia circuit through the bronchoscope.
with high flow oxygen may entrain oxygen through the Complications in this procedure are relatively
side ventilation port of the bronchoscope, still leaving infrequent. Trauma may occur with insertion, involving
the system open. If this is inadequate, then the system dentition, the oral cavity, the pharynx or airway itself.
can be closed, the jet discontinued, and positive pressure Inadequate ventilation may result in hypercarbia or
established by placing a glass window plug on the end of hypoxia. With a closed system, barotrauma may occur,
the bronchoscope, and holding the nose and mouth closed resulting in pneumomediastinum or pneumothorax.

CHAPTER 43 ■ RIGID BRONCHOSCOPY 313
B
A
A B
C D
E
F I GU R E 43 - 3 A: The larynx is exposed directly with an anesthesia laryngoscope that has a curved blade. The tongue base and
epiglottis are elevated. B: While the larynx is visualized with the laryngoscope held in the left hand, the bronchoscope is inserted
behind the epiglottis to the level of the vocal cords with the right hand. C: The operator’s view is now directed down the shaft of
the bronchoscope. The laryngoscope is removed, and the left hand is placed on the upper teeth to support the bronchoscope.
D: With the tip of the bronchoscope behind the epiglottis, the initial view (A) will show both the right and the left vocal cords.
This is not the correct position to advance the bronchoscope into the trachea. The bronchoscope is rotated 90° clockwise so
that the leading tip of the beveled end is to the right lateral side. The entire bronchoscope is shifted laterally to expose the left
vocal cord (B). With this exposure and this orientation, the bronchoscope may be advanced safely into the trachea without
causing trauma to the right vocal cord. The left vocal cord will slide along the bevel and be pushed laterally as the bronchoscope
enters the trachea. E: The bronchoscope has been advanced past the larynx into the trachea for distal tracheal examination. It is
important at this point that the upper hand be placed in firm position to protect the teeth and upper jaw from pressure from the
bronchoscope. The bronchoscope should rest on the left thumb and not against the teeth; this is a position similar to an open
bridge, as used with a cue stick for shooting billiards.
(Adapted with permission from Ferson PF, Eibling DE. Bronchoscopy and tracheoscopy. In: Myers EN, ed. Operative
Otolaryngology: Head and Neck Surgery. 2nd ed. Philadelphia, PA: Elsevier/WB Saunders; 2008.)

REFERENCES 4. Zollner F. Gustave Killian, father of bronchoscopy: histori-

cal vignette. Arch Otolaryngol. 1965;82:656–659.
1. Stock CT. Esophagoscopy. Ear Nose Throat J. 1985;64: 5. Jackson C, Jackson CL. Technique of bronchoscopy
502–503. and laryngoscopy. In: Jackson C, Jackson CL, eds.
2. Grant AK. A century of upper gastrointestinal tract endos- Bronchoesophagology. Philadelphia, PA: WB Saunders;
copy. Med J Aust. 1973;2:903–906. 1950:40–67.6.
3. Berci G. History of endoscopy. In: Berci G, ed. Endoscopy. 6. Ikeda S, Yanai N, Ishikawa S. Flexible bronchofiberscope.
New York, NY: Appleton-Century-Crofts; 1976: xix–xxiii. Keio J Med. 1968;17:1–16.

CHAPTER
Diagnostic and Therapeutic

Fiberoptic Bronchoscopy
44 cn
Paul Bigeleisen
BACKGROUND AND EQUIPMENT intensivists will encounter are stridor, hoarseness, vocal cord
paralysis, and infection. In addition, the fiberscope is usually
Although anesthesiologists frequently use flexible bron- used to confirm endobronchial tube placement (or diagnose
choscopy to assist with difficult intubations and the place- displacement) during surgical procedures requiring lung
ment of double lumen endotracheal tubes, they rarely isolation or single lung ventilation. Less common uses are to
examine the airway distal to the right and left mainstem diagnose inhalation injury, hemoptysis, lobar collapse, and
bronchi. Nonetheless, anesthesiologists and more com- the identification of foreign bodies and obstructing tumors.
monly intensivists, may be called upon to perform some Common therapeutic indications are the removal of foreign
forms of diagnostic or therapeutic bronchoscopy. This bodies, pulmonary toilet, bronchoalveolar lavage, and trans-
chapter summarizes the equipment used in and indica- tracheal percutaneous tracheostomy (see Chapter 39).3
tions for flexible bronchoscopy that anesthesiologists and
intensivists are likely to encounter.
The rigid bronchoscope was invented by Killian in ANATOMY OF THE AIRWAY
1897. Machida and the Olympus Corporation produced the
(FIGS. 44-1–44-7)
first commercially available flexible fiberscope in 1966.1,2
This device used glass fibers to conduct light into the air- The airway begins at the lips and traverses the oral cavity
way and reflected light back to the viewer. In 2001, a new and hypopharynx (Figs. 44-1–44-7). More distally, the en-
type of flexible scope with a light source in the cable and a doscopist encounters the epiglottis, false cords, true cords,
digital camera at the tip of the flexible cable was developed.3 and then the trachea. The trachea has the shape of a tun-
The digital image formed by this miniature digital camera nel. The proximal trachea consists of the membranous
was carried back from the airway by copper wire to a view- posterior portion, which is largely flat striated muscle. The
ing screen. This provided a superior image and eliminated anterior portion is composed of cartilaginous rings and the
the need for glass fibers in the image channel. The resulting thyroid and cricoid cartilages. Approximately 8 cm distal
image had a higher resolution without the pixilation inher- to the cords, the trachea bifurcates into the right and left
ent to the previous generation of fiberoptic scopes. mainstem bronchi; this bifurcation is called the carina.
A flexible bronchoscope consists of a handle with The architecture of the trachea is continued at this level
controls attached to a flexible conduit with three chan- with a membranous posterior portion and a cartilaginous
nels. One channel is a hollow lumen that can be used to anterior portion.
suction sputum, insufflate oxygen, inject saline/local an- As the endoscopist travels distally down the left main-
esthetic, or biopsy tissue. Another channel conveys light stem, the left bronchus bifurcates into the superior and
from the light source to the tip of the bronchoscope. The inferior lobar bronchi. This bifurcation has a similar ap-
third channel returns the image of the airway from the tip pearance to the carina. For this reason, it is often referred
of the bronchoscope to the eyepiece or viewing screen. to as “the mini carina.” The superior lobar bronchus then
Additional equipment consists of a light source, and a gives rise to the superior division bronchus and the lin-
viewing screen or eyepiece (see also Chapter 23).1–3 gular bronchus. These bronchi give rise to segments that
comprise the superior lobe of the left lung. The inferior
lobar bronchus gives rise to four segments that comprise
INDICATIONS the inferior lobe of the left lung.
As the endoscopist travels distally down the right
Fiberoptic bronchoscopy is indicated for diagnostic and mainstem bronchus, he encounters the right superior
therapeutic problems of the airway and lungs. The most lobar bronchus, which gives rise to the superior lobe
common diagnostic indications that anesthesiologists and of the right lung. Continuing down the right mainstem
315

F I GUR E 4 4 -1 Carina as viewed through flexible

bronchoscope.
F I GUR E 4 4 -2 View of right mainstem bronchus.
F IG U R E 4 4 -3 View of right upper lobe

bronchus.

CHAPTER 44 ■ DIAGNOSTIC AND THERAPEUTIC FIBEROPTIC BRONCHOSCOPY 317
FIG U RE 44-4 View of bronchus intermedius.
FIG U RE 44-5 View of left mainstem bronchus.
FIG U RE 44-6 View of left upper lobe bronchus.

F I G U R E 4 4 -7 View of left lower lobe

bronchus.
bronchus, the endoscopist enters the right intermediate these maneuvers are accomplished, the patient is sedated
bronchus, which gives rise to the right middle lobe bron- with fentanyl, midazolam, and dexmedetomidine while
chus and then the right inferior lobe bronchus. The mid- supplemental oxygen is administered. Typical doses are
dle lobe bronchus gives rise to segments that comprise 50 to 100 mcg of fentanyl, 1 to 2 mg of Versed, and 20
the middle lobe of the right lung and the inferior lobe to 40 mcg of dexmedetomidine. Some patients who are
bronchus gives rise to segments that comprise the inferior tolerant to these drugs or who are extremely anxious may
lobe of the right lung. Understanding this anatomy is es- require higher doses.
sential to locate pathology and to localize endobronchial Once sedation is complete, the patient should be
tube placement. asked to open his mouth, and the practitioner should
use a tongue depressor to ensure that the hypopharynx
is numb and that pressure in the hypopharynx does not
SEDATION AND PREPARATION produce a significant gag reflex. If the patient has a signif-
icant gag reflex, additional sedation or topical anesthesia
Patients requiring fiberoptic bronchoscopy may present is warranted. In this setting, some practitioners choose to
intubated and ventilated, or as outpatients. For those pa- anesthetize the IXth cranial nerve with topical application
tients who are intubated, a swivel adapter with a port can or bilateral injections of lidocaine near the tonsillar fos-
be attached to the endotracheal tube and the bronchos- sae. Other practitioners choose to anesthetize the superior
copy can be performed while the patient is intubated and laryngeal nerves with bilateral subcutaneous injections of
ventilated. In some cases, the patient may require signifi- local anesthetic near the hyoid bone (see Chapter 8).
cant additional sedation and/or muscle relaxation to per-
form the bronchoscopy without discomfort to the patient
and without coughing during the procedure. PROCEDURE
If the patient is not intubated, the airway must be
anesthetized, sedation administered, and supplemental After the above maneuvers, the practitioner may wish to
oxygen administered. There are several ways to anes- place an Ovassapian airway in the patient’s mouth. This
thetize the airway. The author’s preference is to apply device opens the hypopharynx and guides the fiberscope
5% lidocaine cream to a tongue depressor and place the toward the glottis. The fiberscope lens is then cleansed
cream and tongue depressor on the patient’s tongue. The with defogging solution and the fiberscope is advanced
cream is allowed to melt into the mouth and hypophar- into the hypopharynx. If the patient is uncomfortable
ynx with subsequent anesthesia to these structures. Once during this procedure, additional local anesthetic may be
this is accomplished, 4 mL of 2% lidocaine with 0.4 mg administered through the bronchoscope channel. During
glycopyrrolate is administered to the patient via a nebu- the bronchoscopy, some practitioners prefer to remove
lizer. The lidocaine anesthetizes the epiglottis, glottis, secretions by suctioning through the fiberscope port.
and trachea. The glycopyrrolate dries secretions. After Other practitioners prefer to insufflate oxygen through the

CHAPTER 44 ■ DIAGNOSTIC AND THERAPEUTIC FIBEROPTIC BRONCHOSCOPY 319
fiberscope port and blow the secretions out of the way. As with any cause of resistance to airflow, air-trapping may
Biopsies may be performed through the bronchoscope occur. Careful hand ventilation with lower tidal volumes,
port. In most cases, the whole procedure (from glottis to reduced inspiratory flow rates, higher FiO2, and preser-
segmental bronchi) can be performed in a few minutes vation of adequate time for exhalation, should minimize
once the airway is prepared. these risks in the intubated patient. Continuous monitor-
ing of vital signs and respiratory parameters throughout
the bronchoscopy will likewise contribute to a safe pro-
COMPLICATIONS cedure.
Complications with this procedure are rare unless biop-

sies are performed. In the case of biopsy, bleeding and/
or pneumothorax may occur. In addition, when bron- REFERENCES
choscopy is performed in the patient on mechanical
1. Sackner MA. Fiberoptic bronchoscopy becomes a medical
ventilation, the bronchoscope is passed through the endo- procedure. Am J Resp Crit Care Med. 2002;166:639–640.
tracheal tube creating the risk of several other complica- 2. Oho K, Amemiya, Barron JP. Practical Fiberoptic Broncho-
tions. These include high peak inspiratory pressures with scopy. Tokyo, Japan: Igaku Shoin Med Pub; 1984.
the potential for barotrauma, and reduced or ineffective 3. Wang KP, Mehta A, Turner JF. Flexible Bronchosocopy.
tidal volumes, leading to hypoventilation and hypoxemia. Malden, MA: Blackwell Science; 2004.

PART
Surgical Situations Requiring Specialized
XIII Airway Management
CHAPTER
Double-Lumen 45 cn
Endotracheal Tubes
William Ehrman and Theresa Gelzinis
Concept bronchus has a smaller diameter, diverges from the tra-

chea at an angle of 45°, and divides to form upper and
lower lobe branches. On the other hand, the right main-
Double-lumen endotracheal (tracheobronchial) tubes
stem bronchus branches off the trachea at a less acute an-
(DLTs) are used in surgeries in which lung isolation is
gle, is wider than the left bronchus, and forms three lobes
essential. This includes situations in which it is essential
(upper, middle, lower). The left bronchus divides into
to prevent secretions and blood from one lung contami-
upper and middle lobes approximately 5 to 6 cm away
nating the other and when one-lung ventilation (OLV)
from the carina in women and between 6 and 8 cm in
is desired. Among the techniques used in OLV, which
men. The takeoff of the upper lobe of the right lung, how-
include bronchial blockers (BBs) and single-lumen endo-
ever, averages approximately 1 to 2 cm below the carina,
tracheal tubes (ETTs)/endobronchial tubes, DLT are the
necessitating specialized right double-lumen tubes that
most popular.
allow the right upper lobe (RUL) to be ventilated.1 The
The first DLT was the Carlens tube, developed and
endobronchial cuff is uniquely designed on right-sided
first used in 1950. The feat ures of this tube included
double-lumen tubes in order to prevent obstruction of
a small internal diameter and a carinal hook, designed
the RUL. The design of the endobronchial cuff for these
to prevent distal migration of the tube (Fig. 45-1). The
right-sided DLTs, which provides isolation with a “slot”
major disadvantages of the Carlens tube are the small in-
in order to ventilate the RUL, varies among manufactur-
ternal diameter of the tube, which produced high resis-
ers (Fig. 45-3). Some right-sided DLT also have a radio-
tance to gas flow and precluded effective suctioning, and
graphic white marker, which facilitates placement with a
also the carinal hook, which made it difficult to place
fiberoptic bronchoscope (FOB).
through the glottic opening. Robertshaw introduced a
Placement of the DLT can be challenging. Alliaume
red rubber DLT in the 1960s, which lacked the carinal
et al studied the number of DLTs that required reposition-
hook and had a larger lumen. Both the Carlens tube and
ing with FOB after being inserted blindly in 24 patients.
the Robertshaw design were made in both right- and
Blind insertion resulted in 78% malpositioning of left-sided
left-sided versions.
DLTs and 83% of right-sided DLTs, such that FOB was
The DLTs in current use are made primarily of poly-
necessary to adjust the position of the tube.2 Klein et al3
vinyl chloride and are disposable. The DLT consists es-
showed that of 200 DLTs that were placed blindly, 35%
sentially of one long endobronchial tube fused to a shorter
were not correctly positioned when fiberoptic bronchos-
ETT. The distal end of the DLT has two high-volume, low-
copy was used to confirm placement. A study by Boucek
pressure cuffs in order to facilitate lung isolation. When
et al4 showed that when comparing the blind technique
the tube is properly placed, one cuff is located in the tra-
with the direct vision technique for left-sided DLT inser-
chea while the other is positioned in either the right or
tion, both methods were successful, but more time was re-
left mainstem bronchus. The endobronchial cuff is blue in
quired using fiberoptic bronchoscopy compared with the
color for better visualization during fiberoptic bronchos-
blind technique (88 vs 181 seconds, respectively).
copy. These tubes are curved to facilitate guidance into
either the right or left mainstem bronchus. The available
types of DLTs are manufactured by Covidien, Mansfiled,
MA, USA (Mallinckrodt), Smiths Medical, Dublin, OH, Evidence
USA (Portex), and Teleflex Medical, Research Triangle
Park, NC, USA (Rusch and Sheridan) (Fig. 45-2). When comparing DLTs with the other methods of lung
Based on the different anatomy of the right and left separation and OLV, DLTs have several distinct advan-
lungs, both right and left DLT are available. The left main tages and are considered the best tool for absolute lung
321

322 PART XIII ■ SURGICAL SITUATIONS REQUIRING SPECIALIZED AIRWAY MANAGEMENT
F IG U R E 4 5 -1 Carlens design Rusch DLT.
F IG U R E 4 5 -2 Left-sided DLTs from left to right: Mallinckrodt,

Portex, Rusch, and Sheridan.
F IG U R E 4 5 -3 Endobronchial cuffs of
right-sided double-lumen endobronchial tubes
from left to right: Mallinckrodt, Portex, Rusch,
and Sheridan.

CHAPTER 45 ■ DOUBLE-LUMEN ENDOTRACHEAL TUBES 323
FIG U RE 45-4 Fiberoptic view of the carina

and the correct positioning of a left-sided DLT
in the left mainstem bronchus with the blue
endobronchial cuff inflated.
isolation. Either lung can be isolated and ventilated hoarseness and sore throat, as well as using bronchoscopy
independently without having to move either a right- or immediately following the surgery in order to objectively
left-sided DLT. The DLTs have an internal diameter that assess vocal cord and bronchial injuries in a population
is able to accommodate either an FOB or suction catheter undergoing thoracic surgery. Patients experienced signifi-
through both the tracheal and bronchial lumens, which cantly more hoarseness in the DLT group compared with
facilitates visualization and suctioning of each lung. the bronchial blocker group (44% vs 17%). Postoperative
A study by Narayanaswamy et al compared DLTs with vocal cord lesions were also increased in patients in the
BBs during thoracic surgery, measuring the time it took DLT group (44% vs 17%), whereas the incidence of bron-
each to isolate the left lung, the number of times each had chial lesions were similar between the two groups.8
to be repositioned, and the mean peak airway pressures Some controversy exists in comparing the use of right-
generated by each device.5 The time for lung isolation was and left-sided DLTs. Due to the narrow margin for error
significantly less for DLTs versus BBs (93 ± 62 vs 203 ± when inserting a right-sided DLT and during repositioning
132 seconds). Also, double-lumen tubes had to be reposi- of the patient (due to obstruction of the RUL bronchus),
tioned far fewer times than the BBs (2 vs 35). With regard opponents of these devices state that the only situations in
to peak airway pressures, not only did DLTs have lower which right-sided DLTs should be used in clinical practice
mean values (16 cm H2O vs 19 cm H2O), but patients be- are when there is an intrinsic or extrinsic left mediastinal,
ing ventilated with BBs had a lower pH and higher PaCO2 thoracic, or bronchial mass that prevents the insertion of
compared with DLTs. a left-sided DLT, and for teaching purposes. Cohen9 has
Double-lumen tubes are the better choice in cases noted that there is a steep learning curve when training
where lung separation is absolutely necessary, as well as to use the right-sided DLTs because there are different
for sleeve pneumonectomies. BBs are more advantageous shapes and locations of the endobronchial cuffs and dif-
when a patient presents with an anticipated difficult air- ferent sizes among the ventilation slots between manufac-
way, if nasal intubation is necessary, if the patient has an turers. Fiberoptic bronchoscopy is essential when using
established ETT and is too unstable to change to a DLT, a right-sided DLT, both during insertion and throughout
and also when the patient will require postoperative me- the case because the margin of error is only 1 to 8 mm
chanical ventilation-especially with a right-sided DLT.6 for right-sided DLT compared with 4 to 6 cm when us-
Double-lumen endobronchial tubes have also been ing a left-sided DLT.1 Campos et al10 found that the time
shown to cause more trauma to the airway, increasing required for correct placement was almost double than the
the incidence of postoperative hoarseness and throat left-sided DLT. Finally, if postoperative mechanical venti-
pain. A review of DLTs over 25 years was conducted by lation is required, a right-sided DLT must be exchanged
Fitzmaurice et al,7 who found that airway injuries were for a single-lumen ETT because the intensive care unit
more common with undersized DLTs, and bronchial rup- staff does not have the training to manage a right-sided
ture was more common with disposable, polyvinylchlo- DLT if it should become improperly positioned. Of con-
ride DLTs. Heike studied the incidence of postoperative cern, when exchanging ETTs, the dependent lung may

become exposed to blood and secretions, or a difficult re- sex and height. However, differences in both individual
intubation may be encountered because of the postopera- anatomy and between double-lumen tubes makes sizing
tive edema, blood, and secretions.9 DLTs for each case more difficult. Both CT scans and
The only contraindication in the use of the right- chest X-rays should be reviewed prior to the placement
sided DLT is an anomalous takeoff of the RUL bronchus of the DLTs in order to identify abnormalities in the tra-
directly from the trachea, which occurs in approximately cheobronchial tree. CT scans can be used to determine
1 in 250 patients.11 With recent improvement in the de- the width of the main bronchus, whereas the length of the
sign of right-sided double-lumen tubes and in the tech- bronchus can be measured using chest X-rays. Benumof
niques used for placement, there are several investigations et al1 determined that the length of the left main bron-
that have shown that right-sided DLTs have similar effi- chus varies between 27 and 68 mm. A standard chest
cacy and safety when compared with BBs and left-sided X-ray magnified the main bronchus approximately 9% in
DLTs.10,12 Ehrenfeld et al retrospectively compared the both length and diameter.15 Also, in patients where the
incidence of these outcome measures between right- and bronchi were not visualized on chest X-ray, Brodsky and
left-sided DLTs when inserted by anesthesiology residents Lemmens16 determined that the left bronchial width was
under supervision. They found that there was no clinically approximately 68% of the tracheal width.
important difference in the incidence and duration of hy- Chow et al demonstrated that the depth of insertion
poxemia, hypercapnia, and high inspiratory airway pres- of DLTs correlates with patient height. They determined
sures when right-sided DLTs were used compared with that the average depth for insertion of a left-sided DLT
left-sided DLTs by infrequent users. In fact, the duration was 29 cm for adults 170 to 180 cm tall. For every 10-cm
of hypoxemia and the frequency of hypercapnia and in- increase or decrease in height, the DLT was advanced or
creased airway pressures were greater for left DLTs com- withdrawn 1 cm, respectively.17
pared with right DLTs.13 When comparing DLTs of the same size between
Right-sided DLTs are more advantageous for certain manufacturers as well as those of the same manufacturer,
surgical procedures. For a left-sided pneumonectomy, Partridge and Russell found that there was a 19 to 40 mm
right-sided DLTs are the more practical choice to provide difference in the distance from the proximal bronchial
OLV. Compared with the left-sided DLT, the right-sided cuff and the tip of the bronchial tube. This length must
DLT does not have to be withdrawn from the left bronchus, be less than the length of the left main stem bronchus,
exposing the dependent lung to blood and secretions.14 which originates at the carina and ends at the takeoff of
the left upper lobe, in order to prevent occlusion at the
carina or of the left upper lobe bronchus. Therefore, at
Sizing least a 10-mm margin of safety is suggested between the
cuff-tip length of the DLT and the length of the left main
Compared with single-lumen ETTs, DLTs require more bronchus.18 If the dimensions of the left bronchus are
meticulous sizing, accuracy of placement, and knowl- known, and a DLT is specifically selected so that the mar-
edge of the tracheobronchial tree on a case-to-case basis. gin of safety is large, studies have shown that confirming
Table 45-1 shows a rough estimate of DLT size based on the DLT placement with a FOB after blind insertion is
unnecessary.19
Table 45-1
Estimation of DLT Size Based on
Sex and Height Preparation
● Standard preparations for direct laryngoscopy (Chapter 5)

Adult Sex Height (in) DLT Size (Fr) and fiberoptic bronchoscopy (Chapter 23)
Female <60 32 ● Check both the 20 cc tracheal cuff and the 3 cc bronchial
60< <63 35 cuff prior to use
>63 37
Male <63 37
Placement
63< <67 39
>67 41 Blind technique for left DLT placement
● Standard technique for direct laryngoscopy (Chapter 5)
Data from Slinger PD, Campos JH. Anesthesia for thoracic surgery.
● Curved (Macintosh) blades allow the best visualization
In: Miller RD, ed. Miller’s Anesthesia. 7th ed. St. Louis, MO: Churchill
Livingstone, 2009, with permission.24 and greatest area to pass the DLT

● The DLT is initially inserted with the concave curvature ● Remove stylet
facing anteriorly ● Advance to mid trachea, rotate 90° clockwise
● Once the DLT is through the vocal cords, the DLT is ro- ● FOB is inserted through the endobronchial lumen, directing
tated 90° counterclockwise if left main bronchus place- the DLT into the right mainstem bronchus (Chapter 23)
ment is desired and rotated 90° clockwise if placement ● Identify the RUL ventilation slot
into the right main bronchus is the goal ● Align the DLT RUL ventilation slot with the takeoff of the
● Remove the stylet RUL bronchus, rotating, advancing, and withdrawing the
● Advance the tube until resistance is felt DLT as necessary
● Proceed to confirmation section below ● Pass the FOB through the RUL ventilation slot to confirm
placement
Alternate blind technique for left DLT placement20 ● Inflate bronchial cuff
● Standard technique for direct laryngoscopy (Chapter 5) ● Confirm that the bronchial cuff is 2 to 5 mm below the
● The DLT is initially inserted with the concave curvature carina in the right mainstem bronchus
facing anteriorly ● Confirm patency of distal endobronchial lumen us-
● DLT is passed through the vocal cords and advanced into ing FOB
the mid trachea
● The bronchial cuff is over inflated to occlude the trachea
● Connect the circuit to the bronchial luman of the DLT

Confirmation of position
● Confirmation that both lungs are being ventilated
of left-sided DLT (Fig. 45-4)
● While ventilating, the DLT is advanced slowly 1 cm at a
time until one lung is being ventilated, which confirms

● Auscultation alone is unreliable but can be used as an
the cuff is occluding the bronchus at the carina. The cuff
adjunct (see above section on Evidence)
remains inflated during this tube advancement
● If the left lung is being ventilated, the cuff is deflated and
● Once DLT is in position, inflate the tracheal cuff with
minimal volume to prevent air leak and confirm bilateral
the DLT is advanced 1 cm
● If the right lung is being ventilated, note the depth
lung ventilation
● Clamp the tracheal lumen proximally, open the port distal
because this is the distance to the carina. Initially at-
to the clamp, ventilate the bronchial lumen, inflating the
tempt to deflate the cuff, withdraw and reinsert the
bronchial cuff until air leak is prevented through the open
DLT. Check to confirm left bronchus intubation. If the
tracheal port
DLT remains in the right bronchus, deflate the cuff,
● Release the tracheal clamp, close tracheal port, auscultate
withdraw the bronchial cuff, rotate the patient’s head
for bilateral breath sounds
to align the chin with the right shoulder, and rotate the
● Clamp each lumen selectively to confirm ventilation of
long axis of the DLT 90° counterclockwise. Inflate the
the contralateral side and absence of breath sounds on the
bronchial cuff and advance the DLT while ventilating
ipsilateral side
the patient until the left lung is the only lung being
● Confirmation with a FOB is recommended
ventilated. Deflate the bronchial cuff and advance the
● With the FOB through the tracheal lumen, check the
DLT 1 cm
● Reinflate the bronchial cuff with 1 to 2 cc of air
endobronchial cuff for herniation of the endobronchial
● Check with FOB to confirm adequate margin of safety (see
cuff over the carina. Figure 45-4 displays the correct posi-
tion of the cuff of a left-sided DLT
Sizing section above)
● Proceed to confirmation section below
● Check the endobronchial lumen for patency and to
confirm the DLT cuff is not too deep, obstructing the left
Direct vision for placement of right-sided DLT upper lobe or the left lower lobe
● Standard technique for direct laryngoscopy (Chapter 5)
● Recheck placement with FOB after both patient and
● Direct laryngoscopy until the DLT is through the vocal
surgical field manipulation to confirm positioning of DLT
cords
● FOB is inserted through the endobronchial lumen, direct-
ing the DLT into the left mainstem bronchus (Chapters 23 Practicality
and 24)
● Cost: Approximately $50 to $80 each
Direct vision for placement of right-sided DLT10,12 ● Definite learning curve, experience necessary
● Standard technique for direct laryngoscopy (Chapter 5) ● FOB experience recommended
● Direct laryngoscopy until the DLT is through the vocal ● Not recommended for anticipated and unanticipated
cords difficult airway situations

Indications ● Patients requiring rapid sequence intubation

● Patients having anticipated difficult airways
● Anomalous takeoff of the RUL bronchus above the carina
Absolute
for right-sided DLTs
● Isolation of a lung to prevent contamination of the con-
tralateral lung, such as with infection, hemorrhage, unilat-

eral lung lavage Complications
● Ventilation of one lung secondary to bronchopleural and
bronchopleural cutaneous fistula, unilateral bulla or cyst, ● Failed intubation

trauma with tracheobronchial disruption, severe lung ● Malposition with inability to collapse isolated lung or
disease with significant V/Q mismatch partial ventilation of dependent lung secondary to cuff
overinflation, surgical field manipulation, change in
Relative patient position
High indications ● Trauma: Sore throat, hoarseness, tracheal or bronchial
● Pneumonectomy, thoracic aortic aneurysm, upper lobec- tissue necrosis from excessive cuff pressure, tracheal or
tomy, lung volume reduction surgery bronchial rupture/injury from a DLT that is too large or
migration of an undersized DLT, barotrauma from migra-
Moderate indications tion of an undersized DLT distally out of the mainstem
● Video-assisted thoracoscopic surgery to allow for maxi- bronchus
mal exposure of the surgical field, middle and lower lobec-
tomy, mediastinal surgery, esophageal surgery, thoracic
spine surgery Special situations
Right-sided DLT Difficult Airway (Chapters 9 to 15)21

● Distorted anatomy by left bronchus tumor, external tu- ● Use of a DLT over a FOB during an awake intubation in a
mor compression, or thoracic aortic aneurysm patient with an anticipated difficult airway (Chapter 23)
● Left-sided tracheobronchial resection, left sleeve resec- ● Use of a lighted stylet (Chapter 20) or fiberoptic laryngo-
tion, left lung transplant, left pneumonectomy because scope (Chapter 24)
withdrawal of a left-sided DLT would increase the pos- ● Use of an exchange catheter at least 83 cm long
sibility of blood contaminating the contralateral lung
Tracheostomies
● Left-sided 41-F DLT have been developed by Sheridan22 to
Contraindications accommodate the shorter airway
● Left-sided 39-F, wire-reinforced silicon (Naruke tube,
● Patient refusal Koken Medical, Tokyo, Japan)23
● Extrinsic or intrinsic obstruction, distorted anatomy
REFERENCES 5. Narayanaswamy M, McRae K, Slinger P, et al. Choosing a

lung isolation device for thoracic surgery: a randomized
1. Benumof JL, Partridge BL, Salvatierra C, et al. Margin of trial of three bronchial blockers versus double-lumen tubes.
safety in positioning modern double-lumen endotracheal Int Anesth Res Soc. 2009;104:1097–1101.
tubes. Anesthesiology. 1985;67:729. 6. Campos JH. Which device should be considered the
2. Alliaume BA, Coddens J, Deloof T. Reliability of ausculta- best for lung isolation: double-lumen endotracheal
tion in positioning of double-lumen endobronchial tubes. tube versus bronchial blockers. Curr Opin Anesthesiol.
Can J Anaesth. 1992:39:687–690. 2007;20:27–31.
3. Klein U, Karzai W, Bloos F, et al. Role of fiberoptic 7. Fitzmaurice BG, Brodsky JB. Airway rupture from double-
bronchoscopy in conjunction with the use of double-lumen lumen tubes. J Cardiothorac Vasc Anesth. 1999;13:322–329.
tubes for thoracic anesthesia. Anesthesiology. 1998;88: 8. Heike Knoll H, Stephan Ziegeler S, Jan-Uwe Schreiber JU,
346–350. et al. Airway injuries after one-lung ventilation: a compari-
4. Boucek CD, Landreneau R, Freeman JA, et al. A comparison son between double-lumen tube and endobronchial blocker:
of techniques for placement of double-lumen endobron- a randomized, prospective, controlled trial. Anesthesiology.
chial tubes. J Clin Anesth. 1998;10:557. 2006; 105:471.

9. Cohen E. Con: right-sided double-lumen endotracheal 16. Brodsky JB, Lemmens HJM. Tracheal width and left double-
tubes should not be routinely used in thoracic surgery. lumen tube size; a formula to estimate left-bronchial width.
J Cardiothorac Vasc Anesth. 2002;16:249–252. J Clin Anesth. 2005;17:267.
10. Campos JH, Massa FC, Christopher F, et al. The incidence 17. Chow MY, Go MH, Ti LK. Predicting the depth of inser-
of upper-lobe collapse when comparing a right-sided dou- tion of left-sided double-lumen endobronchial tubes.
ble-lumen tube versus a modified left double-lumen tube J Cardiothorac Vasc Anesth. 2002;16:456.
for left-sided thoracic surgery: a comparison of two types. 18. Partridge L, Russell WJ. The margin of safety of a left
Anesth Analg. 2000;90:535–540. double-lumen tracheobronchial tube depends on the
11. Benumof J. Thoracic anatomy. In: Benumof J, ed. Anesthesia length of the bronchial cuff and tip. Anaesth Intensive Care.
for Thoracic Surgery. 2nd ed. Philadelphia, PA: Saunders; 2006;34:618–620.
1995:24. 19. Seymour AH, Prasad B, McKenzie RJ. Audit of double-lumen
12. Campos JH, Massa CF. Is there a better right-sided tube endobronchial intubation. Br J Anaesth. 2004;93:525–527.
for one-lung ventilation? A comparison of the right- 20. Russell JW. A logical approach to the selection and insertion of
sided double-lumen tube with the single-lumen tube with double-lumen tubes. Curr Opin Anaesthesiol. 2008;21:37–40.
right-sided enclosed bronchial blocker. Anesth Analg. 21. Campos, JH. Lung isolation techniques for patients with dif-
1998;86:696–700. ficult airway. Curr Opin Anesthesiol. 2010;23:12–17.
13. Ehrenfeld JM, Mulvoy W, Sandberg WS. Performance com- 22. Brodsky JB, Tobler HG, Mark JBD. A double-lumen
parison of right- and left-sided double-lumen tubes among in- endobronchial tube for tracheostomies. Anesthesiology.
frequent users. J Cardiothorac Vasc Anesth. 2010;24:598–601. 1991;74:388–389.
14. Campos JH, Gomez MN. Pro: right-sided double-lumen 23. Saito T, Naruke T, Carney E, et al. New double intrabron-
endotracheal tubes should be routinely used in thoracic chial tube (Naruke tube) for tracheostomized patients.
surgery. J Cardiothorac Vasc Anesth. 2002;16:246–248. Anesthesiology. 1998;89:1038–1039.
15. Hannallah MS, Benumof JL, Ruttimann WE. The relation- 24. Slinger PD, Campos JH. Anesthesia for thoracic surgery.
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size. J Cardiothorac Vasc Anesth. 1995;9:119–121. Churchill Livingstone; 2009.

CHAPTER
46 Bronchial Blockers
in Thoracic Surgery
Ali Abdullah and Ibtesam Hilmi
Concept 3. Single-lumen tube with an incorporated BB (Univent,

Vitaid Ltd., Lewiston, NY, USA).
Two methods are available to achieve one-lung ventila-
tion (OLV), the double-lumen endotracheal tube (DLT)
and the bronchial blockers (BBs). Both of them will allow Evidence
anatomic isolation of the lungs. The absolute indication
for OLV is to protect the healthy lung from ipsilateral dis- There is scant evidence supporting one method of OLV as
eased lung or secretions such as blood, pus, or fluid used clearly superior to the other, so it is ultimately left to the
for pulmonary lavage (as in alveolar proteinosis). In ad- anesthesiologist to select which method of OLV he/she is
dition, lung separation is required during bronchopleural comfortable with (See also chapter 45). The practitioner
fistula to prevent loss of tidal volume, and during resection must understand the fundamental advantages and disad-
of giant unilateral bullae. The relative indication for OLV vantages of each technique in various circumstances, to as-
is to provide an optimal and quiet surgical field during sure the optimal use and the least possible intra-/postoper-
various types of thoracic surgeries such as pneumonec- ative complications. In a study conducted by Campos and
tomies, repair of thoracic aortic aneurysms, and esopha- Kernstine3 in 2003, the authors demonstrated that not only
geal surgery.1 The disadvantages of DLTs are difficulty in did DLT intubation require less time to place but also lung
achieving the accurate position and size restriction, be- collapse was accomplished significantly faster than BBs
cause they are available in specific sizes only (28, 35, 37, (DLT took an average of 2:08 minutes as compared with
39, 41), which makes placement difficult in small patients 3:34 minutes for the Arndt blocker). However, the ability
(pediatric population) or in patients with difficult airway to use BBs across a wide range of patient populations makes
anatomy. DLTs require replacement with a single-lumen these devices increasingly popular and practical devices.
ET at the end of surgery if the patient requires postopera-
tive ventilation, a procedure that can be complicated and
hazardous, especially in patients with difficult airway and/ Preparations
or prolonged surgery resulting in massive fluid shifts with
airway edema.2 ● Anesthetized, intubated patient in neutral position
BBs may be used to provide lung isolation in conjunc- ● Preparation of the fiberoptic bronchoscope
tion with single-lumen endotracheal tube (ETT), eliminat- ● Preparation of the Univent tube or Arndt blocker
ing the requirement to change the ETT at the end of the
procedure. BBs are especially indicated in patients with
difficult airway or abnormal airway (postsurgery or post- Procedure for Arndt blocker
radiation) or during prolonged surgery with large-scale or Fogarty catheter placement
fluid shifts resulting in airway edema, as well as in pa- (Figs. 46-1–46-3)
tients who are already are intubated with single-lumen
ETT before coming to surgery. BBs may be placed through
or alongside the single-lumen ETT, and a 7.0-mm ETT can
● Induce general anesthesia with muscle relaxation
easily allow the passage of a 4.0 fiberoptic bronchoscope
● Intubate the patient with appropriate size single-lumen
with a BB.1 The following are the most commonly used ETT
types of BBs:
● Connect the Arndt blocker connecter to the ETT (Fig. 46-1)
● Maintain anesthesia and ventilation through the side port
1. Fogarty embolectomy catheter (no. 7.0) (Edwards of the connecter that should be hooked up to the anesthe-
Lifesciences, Irvine, CA, USA) with the occlusion sia circuit (Fig. 46-1)
balloon (size 5.0 to 8.0 mL). ● Pass the bronchoscope through the designated port
2. Wire-guided endobronchial blocker (Arndt blocker, (Fig. 46-1) and hook up the blocker to the bronchoscope
Cook Critical Care, Bloomington, IN, USA). using the snared wire (Fig. 46-2)
328

CHAPTER 46 ■ BRONCHIAL BLOCKERS IN THORACIC SURGERY 329
● Pass the bronchoscope and the attached blocker into the ● Univent or BBs can be used in small patients and in pedi-
mainstem bronchus that is to be blocked (Fig. 46-3) atric population; BBs can be inserted alongside the ETT or
● The same procedure may be applied to insert a Fogarty inside the ETT
catheter ● In patients who are already intubated (intensive care unit
patients) before the surgical procedure
Procedure for Univent tube
placement (Figs. 46-4–46-7) Advantages
● Induce general anesthesia with muscle relaxation 1. No need to change the ETT from double lumen to
● Intubate the patient using the appropriate size of single lumen at the end of the procedure
Univent tube 2. Continuous positive airway pressure and suction can
● Pass the fiberoptic bronchoscope through the side port be applied through the BB tube, though not through
(Fig. 46-4) a Fogarty catheter
● Use the bronchoscope to advance the blocker through the
mainstem bronchus to be blocked (Fig. 46-5)
● Inflate the blocker’s cuff and pull out the bronchoscope
(Figs. 46-6 and 46-7) Disadvantages
Practicality 1. Large external diameter of the Univent tube makes it

hard to pass through the vocal cords.
2. Possible to injury to the bronchus by the stiff BBs.
● The procedure requires proficiency in handling the fi-
3. The relatively small internal diameter of the BBs
beroptic bronchoscope. Patients may be kept adequately
makes it difficult to provide adequate oxygenation
ventilated through a different port without affecting the
(with the blocker alone) or suctioning of the pul-
progress of the blocker insertion
monary secretion. The Fogarty catheter is not de-
signed to function as BBs, and when the internal
Indications guidewire is pulled out after the insertion, it is
impossible to reinsert the wire if repositioning is
Apart from providing lung isolation, these devices are help- required for the BBs. Also, due to the tiny internal
ful in the following situations related to thoracic surgery: diameter, it is almost impossible to provide suction
or oxygenation.
● When postoperative ventilation is required in patients
with difficult airway, prolonged surgery with massive
fluid shift
FIG U RE 46-1 Loading the Arndt BB.
DESIGN SERVICES OF

F I GUR E 4 6 -2 The bronchoscope and the

Arndt blocker in the right mainstem bronchus
of an intubating mannequin.
F I GUR E 4 6 -3 The Arndt blocker placed in

the mannikin’s left mainstem bronchus.
F I GUR E 4 6 -4 Loading the Univent tube.
DESIGN SERVICES OF

CHAPTER 46 ■ BRONCHIAL BLOCKERS IN THORACIC SURGERY 331
FIG U RE 46-5 Univent tube in place.
FIG U RE 46-6 Fiberoptic bronchoscope

with the Univent tube blocker placed in
the mainstem bronchus.
FIG U RE 46-7 Fiberoptic bronchoscope

snared to the Univent blocker and placed in
the right mainstem bronchus.
DESIGN SERVICES OF

REFERENCES versus bronchial blockers. Curr Opin Anesthesiol. 2007;20:

27–31.
1. Cohen E. Methods of lung separation. Curr Opin Anesthesiol. 3. Campos JH, Kernstine KH. A comparison of the left-sided
2002;15:69–78. broncho-cath with torque control blocker Univent and the
2. Campos JH. Which device should be considered the wire-guided blocker. Anesth Anlg. 2003;96:283–289.
best for lung isolation: double-lumen endotracheal tube
DESIGN SERVICES OF

CHAPTER
Laser Airway Surgery 47 cn
Adam P. Childers and Patrick J. Forte
Concept anesthesia (TIVA)is a possibility. Jet ventilation, either via

the surgical laryngoscope, rigid bronchoscope, or trans-
tracheally, is another option. For laser surgery involving
Laser airway surgery requires the provision of safe and ap-
a tracheostomy, a laser-safe endotracheal tube replacing
propriate anesthesia, while at the same time providing the
the tracheostomy tube or metal tracheostomy tube can be
surgeon with the best possible exposure and surgical field
used. Laser surgery involving the bronchial tree can be
conditions. Airway management in these cases should be
accomplished with jet ventilation via rigid bronchoscopy.
a collaborative effort between the anesthesiologist and the
surgeon to ensure a positive outcome for the patient. In
this setting, the anesthesiologist must balance the pres-
Intubation Technique
ervation of adequate gas exchange with visualization
and surgical access while minimizing the risk for airway
damage from fire and direct or indirect laser contact. The Direct laryngoscopy and various adjuncts mentioned in
choice of airway management technique depends upon other chapters can be used for placing an endotracheal
several factors, including the indication for and site of the tube for laser surgery. The choice of an endotracheal tube is
surgery, the type of laser used, the anesthesiologist’s level based on multiple factors. Polyvinyl chloride (PVC) tubes
of comfort with the techniques, and the equipment avail- are inexpensive and nonreflective but have a low melt-
able at the surgery location. The techniques available for ing point and are highly combustible. Red rubber tubes
airway management to maintain adequate ventilation and are puncture resistant, nonreflective, and can maintain
anesthesia during laser airway surgery include intubation structure, but unfortunately they are highly combustible.
of the trachea, both rigid and flexible bronchoscopy, jet Silicone rubber tubes are nonreflective but combustible.
ventilation, intermittent apnea, and spontaneous ventila- Metal endotracheal tubes are combustion-resistant and
tion by the patient throughout the procedure. kink-resistant, but often have thick walls, are not as easy
The choice of a specific airway management technique to maneuver, and can reflect the laser and transfer heat.1
depends on multiple determinants, one of which is the Figures. 47-1 and 47-2 show a Mallinckrodt Laser-Flex
surgical site. Laser surgery in the nose and nasopharynx (Covidien, Mansfield, MA) endotracheal tube being used
can be accomplished with a traditional oral endotracheal for microsuspension laryngoscopy and carbon dioxide
tube. The tube does not necessarily have to be a specific la- (CO2) laser removal of a vocal cord lesion.
ser tube if the tube is not in the laser field. The oropharynx
should be packed with saline-soaked gauze during such a
procedure. Laser surgery in the oropharynx requires laser- Endotracheal Tubes
safe endotracheal tubes.
When lasers are used for laryngeal surgery, the size of There are numerous brands of endotracheal tubes with
the lesion is of particular importance in determining the different compositions on the market.
airway management technique. For small, nonobstructing Mallinckrodt Laser-Flex endotracheal tubes have a
lesions of the larynx, a laser-safe tube with saline-soaked corrugated stainless steel shaft with a PVC adapter. These
gauze in proximity to the surgical site is acceptable. For tubes have two PVC cuffs on the adult tubes with two
lesions of the posterior larynx, a tubeless or intermittent separate pilot tubes that run along the inside of the tube
apnea technique is desirable. Perhaps the most challeng- (Fig. 47-3). These tubes are for use with CO2 and potas-
ing situation is the obstructing, malignant tumor of the sium titanyl phosphate (KTP) lasers. There are also cuff-
larynx. For this, communication between the surgeon less versions of this tube available as well (Fig. 47-4).2
and the anesthesiologist is critical, as these patients may Lasertubus (Rusch, Duluth, GA) is composed of a soft
present a difficult intubation, and airway management in- white rubber shaft that is covered with a silver foil and a
terventions differ widely on a case-by-case basis. In gen- Merocel sponge. It also has a double cuff. An advantage is
eral, the smallest practical laser-safe tube should be used. that it can be used with all lasers.3 However, this tube is
Alternatively, intermittent apnea with total intravenous subject to crimping.4
333

Norton (A.V. Mueller, Niles, IL) laser endotracheal any nidus for ignition.14,15 Often times, the cuff is filled
tubes are cuffless, spiral-wound, stainless steel tubes with a with methylene blue solution so that a perforation may be
sandblasted finish. They tubes have a thicker wall and can recognized quickly, as shown in Figs. 47-5 and 47-6.
create an obstruction of the view. Although these tubes are Aluminum foil is often used to wrap the anesthesia
no longer manufactured, they may still be in use in some circuit, from its attachment to the endotracheal tube, well
institutions because they are reusable. These tubes are back from the surgical field, in order to prevent inadver-
resistant to CO2, neodymium:yttrium-aluminum-garnet tent ignition from a wayward laser (Fig. 47-7).
(Nd:YAG), and KTP lasers. This tube is the best option for
upper airway laser surgery with an neodymium:yttrium-
aluminum-garnet (Nd:YAG) laser.5 Bronchoscopy2
Xomed Laser-Shield II (Medtronic ENT Surgical
Products Inc., Jacksonville, FL) endotracheal tubes are Rigid bronchoscopy is an option for laser surgery involv-
silicon rubber tubes that have an aluminum foil tape wrap- ing the trachea, carina, and mainstem bronchi. Through
ping for laser protection in addition to a Teflon cover to the bronchoscope, the anesthesia delivery system can be
give it a smoother surface as compared with the earlier attached and ventilation and anesthesia can be maintained.
Xomed Laser-Shield I (Xomed-Trence, Jacksonville, FL). The rigid bronchoscope is larger than a flexible broncho-
However, neither end of the tube is laser resistant. These scope and provides working channels on its side; however,
are for use with CO2 or KTP lasers only, and are contrain- because of its size and almost complete obstruction of the
dicated with Nd:YAG or argon lasers.6,7 airway, general anesthesia must be used, as opposed to se-
Sheridan Laser-Trach (Hudson RCI, Research Triangle dation that may be used with the flexible scopes. Flexible
Park, NC) endotracheal tubes are red rubber tubes with an bronchoscopy offers the advantage of providing easier ac-
outer copper foil, which is covered by an outer absorbent cess to distal airway lesions.
fabric that creates a smooth exterior surface. It is to be
used with CO2 and KTP lasers only.8
Xomed Laser-Shield I and Bivona Laser endotracheal
Jet Ventilation2
tubes (Bivona, Gary, IN) are not recommended for use.9,10
Jet ventilation consists of using a cannula, needle, or
other similar device that can be positioned on a surgi-
cal laryngoscope, rigid bronchoscope, or may be placed
Adjuncts to Endotracheal Tubes transtracheally. High-frequency jet ventilation or Venturi
jet ventilation may be used, depending on the indication
Metallic foil tapes can be used as a layer of protection around for surgery and location of the airway lesion. Maintenance
an endotracheal tube. These tapes only protect against the anesthesia in these circumstances must be accomplished
direct impact of a laser upon a combustible tube. There is with intravenous agents. High-frequency jet ventilation
still a risk of indirect combustion. The presence of blood on with small tidal volumes provides excellent views of the
the tape can decrease the combustion time. Venture cop- surgical field with minimal movement caused by respira-
per foil tape (Venture Tape Corporation, Rockland, MA) or tory mechanics, allowing for better precision with the la-
3M 425 tape (3M, St. Paul, MN) or 3M 425 tape is recom- ser. The alignment of the jet ventilation cannula is critical,
mended for CO2 lasers,11 whereas only 3M 425 tape is rec- as misdirection can lead to decreased ventilation, increased
ommended for Nd:YAG lasers.12 It is important to note both air in the gastrointestinal tract, or barotrauma leading to
the brand and model number of the tape if used, because possible pneumothorax or pneumomediastinum. This
there are several different lines marketed by each manu- technique is not useful when the compliance of the lungs
facturer. There are disadvantages to wrapping endotracheal is poor or when the larynx is obstructed.
tubes. Wrapping offers no cuff protection and adds thick-
ness to the tube. The protection afforded differs with each
type and brand of material, and the adhesives can ignite if Intermittent Apnea16
exposed. In addition, there may be mucosal injury from
the edges of the wrap. A Merocel Laser-Guard ET protector Intermittent apnea involves tracheal intubation, extuba-
(Merocel, Mystic, CT) is useful for CO2, Nd:YAG, and KTP tion, and reintubation during TIVA. The patient’s trachea
lasers. It is an adhesive silver foil with a sponge coating. is initially intubated following the induction of general
This sponge coating must be kept moist with saline.13 anesthesia. Once TIVA is established, the patient breathes
Saline-filled cuffs on endotracheal tubes add the ben- 100% O2, and when the surgeon is ready, the trachea is
efit of significantly slower deflation times in the event of extubated. The surgeon then performs as much of the
perforation by the laser. The incidence of perforation is the operation as possible until the patient begins to show a
same as air-filled cuffs; however, the saline extinguishes decline in oxygen saturation, at which time the trachea is
DESIGN SERVICES OF

CHAPTER 47 ■ LASER AIRWAY SURGERY 335
reintubated (usually by the surgeon under direct vision), herent advantages and disadvantages with regard to pre-
and all surgical interventions are paused until the patient’s venting fire. In the proper hands and with the appropriate
oxygen saturation returns to normal. This process can training and skills, virtually all airway fires can be avoided.
then be repeated as many times as necessary to complete Nonetheless, the only definite way to prevent fire is to
the procedure. Alternatively, the patient’s lungs can be avoid use of the laser altogether. As such, all anesthesiolo-
ventilated with a mask instead of endotracheal intubation. gists should be prepared to immediately manage an airway
This technique is only suitable for skilled surgeons and fire when providing an anesthetic for laser airway surgery.
anesthesiologists and for relatively short procedures. Upon recognition of a fire involving the endotracheal
tube, all gas flows, including oxygen, should be immedi-
ately stopped and ventilation ceased. Simultaneously, any
Spontaneous Breathing Technique flames should be extinguished with saline and the endo-
tracheal tube with deflated cuff should be removed from
Using a surgical laryngoscope with a side oxygen insuf- the airway. Mask ventilation of the patient’s lungs should
flation port, laser surgery can be accomplished with the occur, followed by examination of the airway to assess for
patient spontaneously breathing. Induction of anesthesia damage.
can be accomplished either by intravenous or inhalational Additional steps can be taken to decrease the risk of
agents, with TIVA maintenance. This is advantageous fire. These include limiting the amount of oxidizing agents
when compared with the intermittent apnea technique, in in the airway, using the lowest possible FiO2 and the mini-
that longer periods of uninterrupted surgical intervention mal laser power in density and duration that is feasible
can take place. Major drawbacks include lack of control for the procedure, and covering the surrounding areas
over the airway and increased risks of surgical debris of the surgical field with saline-soaked towels, as seen in
entering the distal airway. Fig. 47-8.17,18
Fire Prevention Summary

One of the primary goals of airway management for laser There are numerous options for airway management dur-
airway surgery is the prevention of an airway fire. Each ing laser airway surgery. The correct choice is one that
technique and device discussed thus far has its own in- produces safe anesthesia for the patient, provides adequate
FIG U RE 47-1 View of larynx with

Mallinckrodt Laser-Flex endotracheal tube with
double cuff seen just below vocal cords. Upper
arrow indicates the lesion on the vocal cord.
Lower arrow indicates the cuff of the
endotracheal tube.
DESIGN SERVICES OF

F I GUR E 4 7 -2 View of the larynx and vocal

cord with CO2 laser in use.
F I G U R E 4 7 -3 Mallinckrodt Laser-Flex
endotracheal tube with double cuff.
DESIGN SERVICES OF

FIG U RE 47-4 Mallinckrodt Laser-Flex

endotracheal tube, cuffless.
FIG U RE 47-5 Mallinckrodt Laser-Flex double

cuff tube with methylene blue.
DESIGN SERVICES OF

F I GU R E 4 7 -6 Pilot cuffs of Mallinckrodt

Laser-Flex tube filled with methylene blue.
F I GUR E 4 7 -7 Mallinckrodt Laser-Flex

tube with aluminum foil covering the PVC
adapter and circuit.
DESIGN SERVICES OF

FIG U RE 47-8 View of the operating field

draped in saline-soaked towels.
operating conditions for the surgeon, and minimizes risk 9. Sosis MB. Which is the safest endotracheal tube for use
of fire from the laser. The anesthesiologist must be famil- with the CO2 laser? A comparative study. J Clin Anesth.
iar with the techniques described above and be prepared 1992;4:217.
to manage complications as soon as they appear. 10. Sosis MB. What is the safest endotracheal tube for Nd-
YAG laser surgery? A comparative study. Anesth Analg.
1989;69:802.
11. Sosis MB. Evaluation of five metallic tapes for protection of
REFERENCES endotracheal tubes during CO2 laser surgery. Anesth Analg.
1989;69:802.
1. Rampil, IJ. Anesthetic considerations for laser surgery. 12. Sosis MB, Dillon F. What is the safest foil tape for endo-
Anesth Analg. 1992;74:424. tracheal tube protection during Nd-YAG laser surgery? A
2. Foley LJ, Cane RD. Anesthesia for laser airway surgery. In: comparative study. Anesthesiology. 1990;72:553.
Hagberg CA, ed. Benumof’s Airway Management: Principles 13. Sosis MB, Dillon F. Prevention of CO2 laser-induced endo-
and Practice. 2nd ed. Philadelphia, PA: Mosby Elsevier; tracheal tube fires with the laser-guard protective coating.
2007:900–938. J Clin Anesth. 1992;4:25.
3. Sosis M, Kelanic S, Caldarelli DD. An in vitro evaluation of a 14. LeJeune FE Jr, Guice C, LeTard F, et al. Heat sink protec-
new laser resistant endotracheal tube: the Rusch Lasertubus. tion against lasering endotracheal cuffs. Ann Otol Rhinol
Anesthesiology. 1997;87:A483. Laryngol. 1982:91:606.
4. Jacobs JS, Lewis MC, DeSouza GJ, et al. Crimping of a laser 15. Sosis MB, Dillon FX. Saline-filled cuffs help prevent laser-
tube resulting in hypoxemia. Anesthesiology. 1999;91:898. induced polyvinylchloride endotracheal tube fires. Anesth
5. Norton ML, de Vos P. New endotracheal tube for laser sur- Analg. 1991;72:187.
gery of the larynx. Ann Otol Rhinol Laryngol. 1978;87:554. 16. Weisberger EC, Miner JD. Apneic anesthesia for improved
6. Dillon F, Sosis M, Heller S. Evaluation of a new foil wrapped endoscopic removal of laryngeal papillomata. Laryngoscope.
endotracheal tube for laser airway surgery. Anesthesiology. 1988;98:693.
1991;75:A392. 17. Ossoff RH. Laser safety in otolaryngology head and neck
7. Green, JM, Gonzalez, RM, Sonbolian, NJ. The resistance to surgery: anesthetic and educational considerations for
carbon dioxide laser ignition of a new endotracheal tube: laryngeal surgery. Laryngoscope. 1989;99:I26.
Xomed Laser-Shield II. J Clin Anesth. 1992;4:89–92. 18. Sosis MB. Anesthesia for laser surgery. Probl Anesth.
8. Sosis M, Braverman B, Ivanovich AD. Evaluation of a new 1993;7:157–251.
laser-resistant fabric and copper foil wrapped endotracheal
tube. Anesthesiology. 1993;79:A536.
DESIGN SERVICES OF

CHAPTER
48 High-Frequency Jet Ventilation

Miroslav Klain and Joseph Goode
WHAT IS HIGH-FREQUENCY COMMON CHARACTERISTICS

JET VENTILATION? AND OF LFJV AND HFJV
There is often much confusion surrounding the non- Jet ventilation, as the name implies, delivers a jet of fast
specific term “jet ventilation” as it applies to what are streaming gas through a small diameter tubing and cannula
really two different modalities, low-frequency jet ventila- to the patient’s airway. Both types of jet ventilation require a
tion (LFJV) and high-frequency jet ventilation (HFJV). high-pressure gas source, at a minimum wall source oxygen
Additionally, there are other modes of “high-frequency or oxygen via a compressed gas cylinder. Because the vol-
ventilation” (HFV), such as high-frequency oscillation umes are delivered through small diameter devices such as
(HFO) and high-frequency positive pressure ventilation 14G catheters for rescue ventilation, the high pressure can
(HFPPV) that are commonly confused with HFJV. As be thought of as “work” or “potential energy” to overcome
such, it is helpful to distinguish between these ventilatory the resistance of these small diameters.9 Jet ventilation does
modalities. not require a cuffed endotracheal tube and is ideal where
ventilation in “open” systems is required (eg, rigid bron-
choscopy). In fact, jet ventilation is capable of drawing ad-
COMMON CHARACTERISTICS ditional gas into the lungs in excess of what is delivered by
the jet insufflation. This is formally described as a result of
OF ALL MODES OF HFV the jet injector effect, though much of the medical litera-
All types of HFV, including HFJV and HFO, are classi- ture incorrectly attributes this to the Bernoulli or Venturi
fied as forms of positive pressure ventilation. HFPPV is principles.10,11 Many other devices such as gas nebulizers
also a form of positive pressure ventilation, wherein a and oxygen facemasks leverage this effect and both LFJV
conventional style ventilator is operated at the upper and HFJV do as well. Both LFJV and HFJV depend on pas-
end of its functional range. The introduction of both sive exhalation through the natural airways for elimination
HFJV and HFO ventilators has supplanted the use of of CO2, just as in conventional ventilation.
this modality.
The characteristics of all forms of HFV include rates
greater than 60 per minute, which are commonly refer- IMPORTANT DIFFERENCES AND
enced in terms of “cycles per minute”(cpm) or Hertz (Hz) ADVANTAGES OF HFJV OVER LFJV
(eg, 60 cycles per minute or its equivalent, 1 Hz). Tidal
volumes (VT) are usually at or below anatomic dead space, Rate
and the peak airway pressures generated are lower than LFJV is most commonly associated with a manually controlled
those of conventional positive pressure ventilation, result- insufflation device (hand jet insufflator) so that the provider
ing in decreased hemodynamic impairment.1–8 Table 48-1 depressing a demand or on–off valve controls the rate. (See
summarizes and contrasts the common characteristics of also chapter 29). Practically speaking then, rates during the
various modes of HFV with those of conventional me- use of LFJV are generally in the conventional ventilation range.
chanical ventilation. HFJV is of course delivered through a sophisticated mechani-
We will focus in this chapter on LFJV and HFJV as cal ventilator, with electronically controlled solenoid valves
these modalities are the most commonly used by the anes- controlling the flow of gas. Just as in conventional ventilation,
thesia provider in the perioperative period, the application the respiratory rate can be set at a various levels, though most
of HFO being mostly confined to the realm of the adult high-frequency jet ventilators marketed in the United States
and pediatric critical care setting. have a maximum rate of 150 cpm.
340

CHAPTER 48 ■ HIGH-FREQUENCY JET VENTILATION 341
Table 48-1
Comparison of Common Characteristics of HFV Modes and Conventional Ventilation
Conventional Positive
HFJV HFO HFPPV Pressure Ventilation
Rate (Hz)7,8,12,45 1–10 2.5–40 1–2 <1
7,8,45
Tidal volume • At or approaching • <VDS (1–3 mL/kg) • >VDS (2–5 mL/kg) • >VDS required
VDS (2–4 mL/kg) (10 mL/kg)
• Changes passively
as rate, inspiratory
time, and driving
pressure are changed
Peak airway • <20 cm H2O • Plateau pressure • ≥20 cm H2O • ≥20 cm H2O
pressure1–3,5–8, 17,45,46 • Positive pressure ideally <30 cm H2O • Plateau pressure • Plateau pressure
maintained ideally <30 cm ideally <30 cm H2O
throughout the H2O
respiratory cycle
Mean airway • <10 cm H2O • Variable • Ideally <10 cm • Ideally <10 cm H2O
pressure1–3,5–8,17,46 • 2–5 cm H2O above H2O
that seen with
conventional settings
for the patient
Hemodynamic • Minimal • Variable; setting • Variable; setting • Variable; setting
effects47 dependent dependent dependent
Weaning and • Superimposable over • No spontaneous • Depends on • Depends on
spontaneous patient breaths ventilation; usually ventilatory mode ventilatory mode
ventilation1,7,8,48 requires sedation
and neuromuscular
blockade
1 Hz is equal to 60 cycles (breaths) per minute.

Abbreviations: Hz, Hertz; VDS, dead space volume.
It should be noted that during HFJV, the adjustment would indicate 30% of the respiratory cycle as inspiration
of rate has the least impact on either oxygenation or and 70% as expiration). As would be anticipated in con-
ventilation because changes in rate do not directly affect ventional ventilation, increasing the duration of the inspi-
minute ventilation (MV) as they do in conventional venti- ratory phase will result in greater delivery of gas and an
lation modes. MV is primarily determined by the set driv- increased MV. This is true of both LFJV and HFJV.
ing pressure and the inspiratory time.12
Driving Pressure
Inspiratory Time In both LFJV and HFJV, the phrase driving pressure is used
In LFJV, the inspiratory to expiratory ratio of delivered to denote the pressure measured at the gas delivery valve
ventilations is, as with the rate, manually controlled by before it opens to the patient. This becomes a simple ex-
the provider. This frequently results in a great deal of pression for minute volume adjustments: the higher the
breath-to-breath variability. Modern high-frequency jet driving pressure, the higher the delivered minute volume.
ventilators allow for a range of I:E ratios. Most jet ventila- This pressure can be expressed in pounds per square
tors express this in terms of the inspiratory time alone, inch (psi) or in bar (1 bar is approximately equal to at-
with the expiratory time implied (eg, a setting of 30% mospheric pressure at sea level and equal to 14.5037 psi).
DESIGN SERVICES OF

In HFJV (and ideally in LFJV) a reducing regulator al- pressures than in conventional ventilation) than the set
lows for the adjustment of this pressure up or down. The driving pressure. A frequently used example is that with a
maximal pressure that one is able to obtain depends on set driving pressure of 20 psi, a standard length of deliv-
the compressed gas source, but for most central gas de- ery tubing, and incorporating a 14G catheter, one could
livery systems in the United States this is approximately expect to deliver between 500 and 600 mL with a 1 sec-
50 psi. For most patients, optimal driving pressure settings ond inspiration.18,19 Pressure in the lungs, then, depends
will be between 20 and 30 psi, but pulmonary-related co- on the volume delivered during each breath. The greater
morbidities could result in the need for either higher or the volume delivered, the greater the pressure. A review
lower settings. In HFJV, driving pressure is one of the key of the literature reveals that the most common occurrence
determinants of MV, oxygenation, and carbon dioxide in cases of barotrauma is the development of an obstruc-
elimination.13,14 tion, often in the upper airway, which impedes egress.20–26
If insufflation continues and this obstruction remains
Airway Pressures unrecognized, barotrauma ensues. This risk is higher in
Airway pressures in jet ventilation are determined by the the setting of LFJV as the detection of impaired exhala-
amount of volume delivered to the lungs. The primary tion depends on the vigilance of the provider delivering
determinants of this are the set driving pressure and the the manual insufflations. HFJV offers the advantage of an
inspiratory time. Increased driving pressure provides in- integral alarm system designed to detect outflow obstruc-
creased “energy” to overcome the resistance of the small tion. Modern high-frequency jet ventilators incorporate a
diameter delivery tubing and, thus, increased volumes. sophisticated switching system that enables the delivery
An increased inspiratory time functions just as it does tubing itself to act as pressure tubing to a dedicated pres-
in conventional ventilation to deliver greater volumes. sure transducer. At the end of the expiratory cycle, back-
In general, peak airway pressures during HFJV are lower pressure in the airway is measured, and if the set alarm
than those generated during conventional positive pres- limit is exceeded, delivery of additional breaths is stopped.
sure ventilation, and this can be of great advantage across This occurs at the end of each respiratory cycle, regardless
the range of applications for HFJV.5,6,15–17 Because the of the set rate, providing breath-to-breath detection of po-
lungs never fully exhale during HFJV, positive pressure is tential outflow obstruction. The alarm level is adjustable
maintained throughout the respiratory cycle. As a result, but is often nondefeatable. A typical setting for this alarm
although peak airway pressures are lower than conven- limit is 20 cm H2O.
tional ventilation, mean airway pressures between the two
modes are generally equivalent. Airway pressures in LFJV Aspiration Protection in “Open Systems”
depends heavily on the operator manually controlling the Frequently, jet ventilation of either type is used in the set-
rate and I:E ratio. Other significant contributing factors ting of “open” ventilatory systems (no cuffed endotracheal
would include the cross-sectional area of the trachea and tube). Because of this, there is always the potential risk of
the ID and length of the delivery catheter. Animal studies aspiration. However, when using HFJV with a minimum
have reported a range of pressures between 20 and 50 cm rate setting of 60 cpm and a minimum inspiratory time of
H20 using LFJV via transtracheal puncture with either a 30%, it has been shown that secretions will be pushed away
14 g or 16 g catheter. from the glottic opening and to some extent expelled from
the upper trachea (Fig. 48-1).27 Although this is not to be
construed as complete a protection as a cuffed endotra-
cheal tube, smaller amounts of secretions and fluids can
POTENTIAL COMPLICATIONS be kept out of the airway. This protection is not present
OF LFJV AND HFJV during the use of LFJV, as typically LFJV is not occurring
at the minimum required rate setting of 60 cpm. Other,
Barotrauma less common, potential complications of these modes of
The most common complication of either type of jet ven- ventilation are summarized in Table 48-2.
tilation is barotrauma, and the most common underlying
etiology is unrecognized obstruction to outflow, either
through the natural airways or in some circumstances GUIDELINES FOR THE USE OF HAND
through an endotracheal tube. This is counter to a com- JET INSUFFLATORS
mon misconception that the high-pressure gas source it-
self is the cause of barotrauma. As discussed earlier, the As noted earlier, unrecognized obstruction to outflow is
high-pressure gas is essentially used as work to overcome almost always a contributing factor in barotrauma during
the resistance of the small diameter ventilator delivery all forms of jet ventilation; however, there is a predomi-
tubing and whatever jet device is attached to it. The pres- nance of cases associated with LFJV in the literature.
sures generated at the point of exit are significantly lower This is in large part due to the lack of the previously de-
(consider that the hallmark of HFJV is lower peak airway scribed end expiratory monitoring system that exists in
DESIGN SERVICES OF

F I GUR E 4 8 -1 Movement of secretions from the trachea toward the glottic opening during HFJV. A: the dye-colored secretions
are more distal in the trachea and have been pushed closer to the glottic opening (B).
Table 48-2
Summary of Potential Complications and Disadvantages of the Use of LFJV and HFJV
LFJV HFJV
Tension pneumothorax √ √
Tension pneumomediastinum √ √
Subcutaneous air (misplaced transtracheal √ √
jet catheter)
Aspiration (in open systems) √ Only if rate is <60 and
inspiratory time <30%
Lacks end expiratory pressure monitoring √ Available
Hypothermia √ √
Lacks humidification system √ Available
all modern high-frequency jet ventilators. Because of this Device Specification

the authors, though recognizing the important role trans- There are four primary components that should be present
tracheal jet ventilation plays in rescue maneuvers as per on any hand jet insufflation device: (1) a connection to a
the American Society of Anesthesiologists (ASA) Difficult high-pressure gas source, (2) a reducing regulator, (3) an
Airway Algorithm, strongly discourage the elective use of on/off (demand) valve, and (4) a pressure gauge.
hand jet insufflators by practitioners with little or no ex- Depending on the setting, these devices can be connected
perience with jet ventilation. The following are some sug- to wall source oxygen or to an oxygen cylinder. In either case,
gested guidelines in regard to the application of LFJV via a reducing regulator is essential to decrease the pressure from
hand jet insufflators.24 the usual 50-psi wall source pressure (or the potentially even
DESIGN SERVICES OF

higher cylinder pressure). There is also a button or lever that of transtracheal jet ventilation are required, transition to
is manually depressed to open a valve and allow the flow of HFJV is a good choice if available.24
gas to commence. What is often overlooked is the pressure
regulator, which displays the pressure setting at the valve be- Myths of LFJV
fore it is opened. Every hand jet insufflation device should A common misconception is that by attaching a resuscita-
have one. Most do, but it is critical that the gauge be proximal tion bag to the transtracheal catheter (multiple methods
to the on/off valve. Many commercial preparations of these have been published, most commonly by placing a 15 mm
devices are sold with the gauge distal to the on/off valve, so endotracheal tube adaptor into a 3 cc syringe, which is
that the set driving pressure is never known (Fig. 48-2). Any then connected to the catheter) one may be able to ad-
pressure reading that registers during the open phase is of equately ventilate the patient. This myth persists despite
little value clinically, and these gauges are incapable of mea- multiple studies demonstrating the ineffectiveness of this
suring backpressure during exhalation as they are calibrated approach; Yealy et al demonstrated maximal VT through a
to measure psi and not cm H2O. 14G catheter of 235 mL with this type of system.28
Another misconception is the reliability of devising a
Ventilation Guidelines connection from the common gas outlet of the anesthesia
Multiple studies have characterized the flow delivery pro- machine to the placed transtracheal catheter. The ability
files of transtracheal jet ventilation catheters. Yealy et al18,19 to achieve adequate VT by this method is entirely machine
demonstrated that at a set pressure of 25 psi with a 14G specific and depends on the positions of the low-pressure
catheter, up to 1,000 mL/second could possibly be de- relief and check valves. As described by Olympio,29 if the
livered; at a pressure of 50 psi this can be upwards of check valve is positioned proximally to the relief valve,
1,700 mL/second. Given this, it is clear that insuffla- then it is not possible to generate adequate driving pressure
tion times of 1 or even half a second can produce more for transtracheal ventilation. Therefore, one must know the
than adequate VT for both oxygenation and ventilation. specifics of each individual anesthesia gas machine (AGM),
Delivered volumes and airway pressures increase linearly as some larger institutions use multiple models and manu-
with increases in driving pressure and/or inspiratory time, facturers, which can be problematic. Additionally, some
potentially increasing the risk of barotrauma. We recom- newer AGMs have no common gas outlet at all.
mend that insufflation should be no longer than 1 second,
with a minimum inspiratory to expiratory ratio (I:E) of
1:2, if not 1:3, especially as obstruction to outflow is a
primary etiology for barotrauma. We further recommend GUIDELINES FOR THE USE OF HFJV
that when hand jet insufflation is necessary, a single pro-
vider should be dedicated to this task alone. During an The Role of Rate, Inspiratory Time, and
emergency airway scenario, the dynamics of airway inflow Driving Pressure in Gas Exchange
and outflow can show considerable fluctuation; it is un- Much as in conventional ventilation, a primary factor
likely that a single provider can safely manage this and in both oxygenation and CO2 elimination is minute vol-
other hemodynamic or anesthetic needs. If longer periods ume. As mentioned above, rate has little effect on either
F I GU R E 48 - 2 Two examples of Hand Jet Insufflators: incorrect (left) and correct (right) placement of the pressure gauge.
A = pressure gauge; B = ‘on-off’ or demand valve; C = pressure reducing regulator.
DESIGN SERVICES OF

oxygenation or carbon dioxide elimination, especially in tidal CO2 value is never obtained. The gold standard for as-
the commonly used range of 100 and 200 cpm. In general, sessment of adequacy of oxygenation and ventilation is an
the higher the respiratory rate, the greater the minute vol- arterial blood gas. If ventilation is being delivered through
ume that will be needed to achieve a similar PaCO2 level. a cuffed endotracheal tube using one of the commercially
When rates exceed 400 cpm, CO2 elimination begins to available jet ventilation adaptors (eg, the Acutronic Swivel
be further impaired.12 Most high-frequency jet ventilators Connector with 15 mm Jet Catheter: Acutronic Medical
display both VT and minute volume, but there is no di- Systems AG, Hirzel (Zurich), Switzerland), one can in-
rect way to adjust VT as with conventional ventilators. VT termittently stop HFJV, deliver a standard tidal breath us-
changes passively as rate, driving pressure, and inspira- ing the anesthesia circuit/reservoir bag, and observe the
tory time are changed (individually or in combination). measurement on a capnograph. It is best to catch the first
Minute volume (and thus VT) linearly increases as driving tidal breath on the monitor as subsequent CO2 measure-
pressure is increased. Minute volume is also increased, as ments will begin to reflect the result of manual ventilation
would be expected, when inspiratory time is increased. (Fig. 48-3).
The MV required for normal adequate oxygenation and
eucapnia is generally higher than in conventional ventila- Anesthetic Management
tion, usually twice as large.30 As the vaporizers used for delivery of modern inhaled an-
esthetics are not designed for use with high-pressure gas
Initial Settings sources, it is not yet technically feasible to safely use in-
Generally accepted starting ventilatory settings for HFJV haled anesthetics with HFJV. Depending on the model of
are a rate of 100 cpm and an inspiratory time of 30%. It jet ventilator available, it may be possible to use an admix-
is recommended that the initial driving pressure setting ture of nitrous oxide, which comes as a compressed gas.
be low (in the event that there is unrecognized outflow But because it is difficult to scavenge the expired gas when
obstruction) and rapidly increased while observing chest a closed system is not used, its use is not recommended.
excursion and data from standard monitors, especially The most common method of managing the anesthetic
pulse oximetry. A good starting setting for the integral end during HFJV is to use a total intravenous anesthetic tech-
expiratory pressure alarm is 20 cm H2O. nique appropriate to each individual patient.
Monitoring the Adequacy of Ventilation Humidification

Capnography is unreliable in the setting of HFJV. At best, a Because large volumes of cold, compressed gases are de-
depressed waveform will be displayed, if any at all. As HFJV livered to the patient during HFJV, it is necessary to de-
results in some degree of constant pressure in the lungs, full liver humidification for procedures that will last longer
passive exhalation as in conventional ventilation is never than 60 minutes to avoid drying of the airway mucosa.
achieved. In fact, there is some constant egress of gas, even All of the high-frequency jet ventilators sold in the United
during the inspiratory phase. Because of this, a true end States have the option of an integral heated humidification
FIG U RE 48-3 Diagrammatic representation of a typical

Pressure monitoring connection to the anesthesia circuit during the use of HFJV.
High frequency jet ventilator
Jet patient connector
Exhalation: to
anesthesia circuit APL valve on
anesthesia circuit
in fully open position
Endotracheal tube
Anesthesia circuit
to patient
reservoir bag
DESIGN SERVICES OF

system. It is also possible to administer humidification by recommended (≤15 psi). Fourth, the jet can be used to
attaching a y-connector at the tip of the jet delivery tubing; nebulize local anesthetic agents in the trachea, helping
an infusion of normal saline can then be administered into to block the sensory pathways of the recurrent laryngeal
the jet stream, allowing it to be nebulized. nerve. Fifth, the continuous egress of gases during HFJV
can both provide some degree of protection from aspira-
tion and partially stent open the glottis to facilitate endo-
PERIOPERATIVE APPLICATIONS OF HFJV tracheal tube placement.6,31,32
Most practitioners are only acquainted with the role of jet ENT Procedures
ventilation in the management of the difficult airway as
Management of cases that involve examination and/or
per the ASA Difficult Airway Algorithm. However, HFJV
manipulation within the larynx requires that both the
has been used in various circumstances in the periopera-
surgeon and the anesthesia team must share the same
tive setting (Table 48-3), and there are newly emerging
space. Although oftentimes a very small 5.0 mm Internal
settings for its application. Although not exhaustive, we
Diameter (ID) endotracheal tube will be adequate in terms
briefly highlight some of the potential applications for
of visualization for the surgeon, there are instances when
HFJV below.
even these are too large. The smaller catheters and special-
Elective Transtracheal Jet Ventilation ized endotracheal tubes that are used with HFJV or LFJV
for Assistance with Fiberoptic eliminate competition for the airway with the surgeon and
Bronchoscopy provide reliable, continuous ventilation in the setting of an
“open” system. A 14 French insufflation catheter is usu-
In the setting of a recognized difficult airway, the ASA
ally adequate for adults (10 F for children). There are spe-
Difficult Airway Algorithm lists awake fiberoptic intuba-
cialized tubes, such as the Hunsaker Mon-Jet Ventilation
tion as an option that should be seriously considered.
Tube: Medtronic, Minneapolis, MN, which have been de-
It is possible to use HFJV in this situation via percuta-
signed for use during microlaryngeal laser surgery.33
neous placement of a 14G catheter across the cricothy-
roid membrane, after the usual application of topical
Rigid Bronchoscopy
local anesthetics for awake fiberoptic intubation. There
are several potential advantages to this technique. First, During rigid bronchoscopy, HFJV provides all of the
it allows for confirmation of the ability to ventilate the expected advantages in the setting of an open ventilatory
patient. This is especially valuable in the setting of lim- system (see chapter 43). The ability to provide uninter-
ited mouth opening or maxillofacial injury and in the rupted ventilation provides for greater hemodynamic sta-
presence of cervical spine injuries where hyperexten- bility for the patient. There are two primary methods to
sion of the neck is of concern. Second, it provides for establish HFJV in this setting. Most rigid bronchoscopes
direct intratracheal administration of oxygen. Third, it have a side arm that either has an integral attachment point
is well tolerated by patients at the low driving pressures for the jet delivery tubing or accepts an appropriate adap-
tor. A second approach is to nasotracheally insert a 14 F
insufflation catheter under direct vision. The broncho-
scope itself is the conduit for exhalation in either setting.
Table 48-3
The advantage of the insufflation catheter is that it may
be left in place, maintaining ventilation, during periods
Number of Cases Accumulated in Various when the rigid bronchoscope is removed. Additionally, the
Perioperative Settings insufflation catheter may be left in place at the end of the
procedure to provide respiratory support during weaning
Unpublished data from accumulated cases at and emergence from the anesthetic.4,34,35
Montefiore University Hospital through from 1982
through 1996 Major Airway Reconstructive Procedures
Location for HFJV The ability to deliver ventilation through small diameter
Operating room 1987 insufflation catheters can provide some unique advantages
for the anesthetic and surgical management of reconstruc-
Postanesthetic care unit 63 tive procedures on the tracheobronchial tree. In some
ICU 279 settings, such as complete carinal reconstruction, the
Transport 120 application of HFJV is the only viable alternative to cardio-
pulmonary bypass, providing uninterrupted ventilation
Lithotripter 83
through low-profile devices, which do not impede access
Other 64 to the entire circumference of the trachea and mainstem
bronchi, essential for achieving good anastamosis.36–39
DESIGN SERVICES OF

Alternative to Continuous Positive Airway had an SpO2 of < 90% on nasal cannula received HFJV via
Pressure in One-Lung Ventilation a nasotracheally placed 11 F tube exchange catheter. All
Ventilation/perfusion mismatching can result in peri- patients remained spontaneously breathing over top of the
ods of hypoxia during one-lung ventilation for thoracic jet flow (set between 0.5 and 1.2 bar). All maintained SpO2
procedures. Standard interventional maneuvers are the greater than 97%, tolerated the modality well and had no
institution of continuous positive airway pressure (CPAP) resultant complications.43
at 5–10 cm H2O or the application of positive end expira-
Flexible Bronchoscopy and Endotracheal
tory pressure (PEEP) to the ventilated lung. An alternative
Tube Exchange
approach is to apply low driving pressure HFJV to the
operative lung. Wilks et al40 reported minimal lung dis- With the introduction of specific adaptors for use during
tention and improved oxygenation with the use of HFJV fiberoptic bronchoscopic procedures in intubated patients,
at a driving pressure of 15 psi (Fig. 48-4). providers often forget that significant decreases in arterial
oxygenation can occur. This is a result of either a loss of
Extracorporeal Shock Wave Lithotripsy delivered volume when the fiberoptic scope is introduced
Cormack et al compared two anesthetic management strat- through the diaphragm of the bronchoscopy adaptor, or a
egies for Extracorporeal Shock Wave Lithotripsy (ESWL) leak of delivered volume if the diaphragm does not tightly
performed under general anesthesia: spontaneous ventila- seal against the bronchoscope. Guntupalli et al demon-
tion versus HFJV. The smaller VT delivered during HFJV strated that tracheobronchial suctioning can significantly
created less movement of the diaphragm and the kidney decrease PaO2 up to 90 torr, but using HFJV during these
with each breath, resulting in less excursion of the tar- procedures resulted in a decrease of PaO2 of only 15 torr.44
geted kidney stone out of the shock focus. They noted This difference is seen because of the uninterrupted nature
significantly fewer shocks for effective stone ablation of the ventilation provided by HFJV in this setting. This
(median 2000 for HFJV vs median 3000 for spontaneous difference may be critical in patients exhibiting symptoms
ventilation) with no difference in postoperative recovery of respiratory failure. For the same reasons, HFJV should
time.41 These authors speculate that as fewer shocks are be the preferred mode of ventilation during endotracheal
needed when using HFJV, this could result in a decrease tube exchange. Most commercial airway exchange cath-
in the incidence of postoperative pain and nausea associ- eters have a hollow lumen and provide adaptors for con-
ated with ESWL when performed under general anesthesia nection to either a hand jet insufflator or a high-frequency
with spontaneous ventilation. jet ventilator. There have been cases of barotrauma in at-
tempts to ventilate during endotracheal tube exchange.21,24
Radiofrequency Ablation of Atrial Fibrillation Benumof has identified one source of the error: using a
catheter with too large a diameter with the result that an-
The use of percutaneous radiofrequency catheter abla-
nular space in the endotracheal tube around the exchange
tion as an alternative to the surgical MAZE procedure for
catheter is insufficient for exhalation (obstruction to out-
the treatment of chronic paroxysmal atrial fibrillation has
flow).21 HFJV offers clear advantages in this setting: un-
become widespread. The procedure necessitates an atrial
interrupted ventilation providing better cardiopulmonary
septal puncture to access the posterior left atrium. Many
support and hemodynamic stability for the patient as well
centers perform this procedure under heavy sedation, but
as early detection of any obstruction to egress via the built
Goode et al42 were able to demonstrate significantly re-
in end-expiratory alarm system.
duced procedure times by using general anesthesia and
Aside from these specific indications, we believe that
HFJV. HFJV creates an essentially quiet cardiac field for
HFJV should be used in situations where its characteris-
the procedure, primarily by reducing the variation in left
tics offer an advantage during ventilatory support. These
atrial volume seen in both spontaneous and conventional
include emergency transtracheal ventilation (because of a
mechanical ventilation. Fewer ablations were needed as
lower incidence of barotrauma), airway leaks and bron-
this more stable posterior left atrial environment resulted
chopulmonary fistula (because of the ability to ventilate
in decreased incidence of ablation catheter dislodgement.
even in the presence of airway leaks), any open system
Oxygen Insufflation in Sedation Cases where it would be deleterious for the patient to have ven-
tilation interrupted, and procedures requiring a quiet op-
Drawing on previously reported clinical experience using erating field as the respiratory-related motion of the heart,
elective TTJV for awake fiberoptic bronchoscopy, Chernus lungs, and abdominal organs is considerably less than in
presented an intriguing series of cases in which 20 patients conventional ventilation.
scheduled for esophagogastroduodenoscopy (EGD) who
DESIGN SERVICES OF

F I GUR E 4 8 -4 The use of HFJV in place

of CPAP in one-lung ventilation. A: the fully
inflated lung in an open thoracotomy. B: the
same lung collapsed after lung isolation using a
double lumen endobronchial tube. C: the lung
with low driving pressure HFJV applied.
DESIGN SERVICES OF

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during sedation for endoscopies. European Society for Jet lation. Br J Anaesth. Oct 1971;43(10):932-939.
Ventilation. Heidelberg, Germany;2008.
44. Guntupalli K, Sladen A, Klain M. High-frequency jet ven-
tilation and tracheobronchial suctioning. Crit Care Med.
1984;12(9):791–792.
DESIGN SERVICES OF

PART
Unique Facets of Airway Management
XIV by Discipline
CHAPTER
Airway Management in Critical 49 cn
Care Medicine
James M. Dargin and Lillian L. Emlet
INTRODUCTION PERSONNEL AND EQUIPMENT

Airway management in critically ill patients, who have Emergency tracheal intubation outside of the operat-
exhausted their physiologic reserve and are under undue ing room (OR) is associated with a decreased complica-
stress, can have disastrous consequences. Further com- tion rate when performed in the presence of an attending
plicating matters, the critically ill often require airway physician, rather than by unsupervised trainees.1,5
management in settings outside of the intensive care Complications during airway management in the critically
unit (ICU) where experienced providers and appropriate ill also can be minimized by having the proper equipment
equipment and medications may not be readily available. and medications necessary to manage the difficult airway.
Hypoxia, hemodynamic instability, elevated intracranial Unfortunately, only 50% of ICUs in the United States have
pressure, emesis, gastrointestinal bleeding, and postex- a difficult airway cart and fewer than 5% have the equip-
tubation laryngeal edema are common conditions that ment suggested in the American Society of Anesthesiology
make airway management challenging in the critically Practice Guidelines.6,7 At the University of Pittsburgh
ill. Not surprisingly, complications during airway man- Medical Center, we have standardized the approach to air-
agement account for a significant percentage of adverse way management in the critically ill by creating a portable
events in the ICU.1–3 The medical complexity of patients airway bag that contains the medications and equipment
in the ICU is an important contributing factor to airway- necessary to manage both routine and difficult airways
related complications. Therefore, an understanding of the (Table 49-1).8 The contents of the airway bag are uniform,
individual patient’s physiologic derangements can help such that any desired piece of equipment can be quickly
formulate an airway management plan to avoid adverse located (Fig. 49-1). The standardized airway bag is stored
events. in each ICU, is brought to all medical emergency calls
within the hospital, and is restocked by the hospital cen-
tral supply department after each use.
SETTING
Although the majority of critically ill patients undergo tra- AIRWAY ASSESSMENT
cheal intubation in the ICU setting, airway management
may also occur in the inpatient wards or elsewhere in the Predicting the difficult airway allows for preparation of
hospital, such as the radiology suite or special procedures the proper equipment and resources to ensure successful
laboratories. In the ICU, equipment such as infusion pumps, intubation on the first attempt. Unfortunately, many of
dialysis machines and mechanical ventilators limit access to the traditionally described predictors of difficult intuba-
the patient. Air mattresses used to prevent pressure sores in tion have not been validated in the critically ill.9 In fact,
ICU patients can make proper positioning difficult as well. Mallampati classification, thyromental distance, and neck
Outside of the ICU, airway equipment, appropriate medica- mobility cannot be assessed in many patients undergoing
tions, and experienced personnel may not be readily avail- emergency intubation due to lack of patient cooperation,
able. Medical emergency teams staffed by expert personnel altered mental status, or cervical spine immobilization.10
who are appropriately equipped and available 24 hours per However, several conditions commonly encountered in
day may help to overcome such challenges.4 the critically ill will likely cause difficulties during airway
351

352 PART XIV ■ UNIQUE FACETS OF AIRWAY MANAGEMENT BY DISCIPLINE
Table 49-1
Medical Emergency Team Airway Bag Contents
Routine Airway Equipment Difficult Airway Equipment

Tongue blade Intubating stylet (bougie)
Laryngoscope handle with batteries Airtraq optical laryngoscope
Magill forceps Laryngeal mask airway
Gloves Jet ventilation equipment
No. 3, no. 4 Miller blades Cricothyrotomy equipment
No. 3, no. 4 Macintosh blades Availability of fiberoptic bronchoscope on request
No. 6, no. 7, no. 7.5, no. 8 endotracheal tubes Availability of video laryngoscope (Glidescope)® on request
Endotracheal tube stylets
Disposable colorimetric CO2 detector
Oral airways
Nasal airways
Medications
Etomidate
Propofol
Benzocaine spray
Succinylcholine
Rocuronium
10cc syringe
F I GUR E 4 9 -1 A: the airway bag used in the ICUs and during medical emergency calls at the University of Pittsburgh Medical Center.
B: the contents of the airway bag used in the ICUs and during medical emergency calls at the University of Pittsburgh Medical Center.
management. Upper airway obstruction from a hematoma, reactive airways; poor lung compliance in patients with
abscess, angioedema, epiglottitis, or postextubation laryn- significant airspace disease; and reduced thoracoabdomi-
geal edema can hinder mask ventilation, intubation, and nal compliance from ascites, abdominal compartment syn-
the use of an extraglottic rescue device. The presence of drome, or flail chest can make the use of mask ventilation
blood, secretions, or vomitus in the airway can obscure or extraglottic rescue devices difficult. Thus, a patient who
laryngoscopic view. In addition, increased resistance from would be predicted to have a routine airway for elective
DESIGN SERVICES OF

CHAPTER 49 ■ AIRWAY MANAGEMENT IN CRITICAL CARE MEDICINE 353
intubation can pose a challenge when critically ill, and it hypotension in patients who require a high sympathetic
would be wise to over-prepare, rather than under-prepare drive to maintain their blood pressure, and a reduction in
during airway management in the critically ill. dose from the standard 0.3 to 0.2 mg per kg may mitigate
this effect. Etomidate causes a reversible, dose-depen-
dent decrease in cortisol production and should be used
PREOXYGENATION with awareness of this side effect in patients with sepsis,
who have a high incidence of critical illness-related adre-
Increased oxygen consumption, ventilation-perfusion nal insufficiency. Ketamine appears to be an acceptable
mismatching, decreased cardiac output, and decreased alternative to etomidate in septic patients.16 Ketamine
hemoglobin concentration all reduce the time to hemo- causes a sympathomimetic response that can lead to an
globin desaturation in critical illness.11 In patients with increase in heart rate and blood pressure, which may
cardiopulmonary compromise, the traditional technique be detrimental in some cases (eg, aortic dissection) and
of preoxygenation may not result in large increases in desirable in others (eg, shock states).17 Ketamine also
oxygen saturation, and prolonged periods of attempted possesses bronchodilator properties and may be useful
preoxygenation may even worsen oxygenation in in asthma or chronic obstructive pulmonary disease.
the critically ill.12 Thus, the goal of preoxygenation in the However, ketamine may cause an increase in intracra-
critically ill should be to improve the O2 saturation to the nial pressure, and its use in patients with intracranial
mid to high 90% range, and tracheal intubation should pathology is controversial. Propofol decreases intracra-
not be delayed while trying to further preoxygenate a nial pressure and cerebral oxygen demand, may have
patient who has an acceptable O2 saturation. In cases some antiepileptic properties, and has a rapid onset and
of hypoxia refractory to high-flow oxygen, assisting the a short half-life. However, propofol causes vasodilation
patient with positive pressure breaths delivered with a and can result in hypotension, particularly in hypovo-
bag-valve-mask or with noninvasive positive pressure lemic patients and the elderly.17 Propofol may be con-
ventilation may be helpful in achieving an O2 satura- sidered for hemodynamically stable patients with status
tion greater than 90%.13 The supine position tends to epilepticus or intracranial hypertension. Midazolam has
cause atelectasis of the well-perfused lung bases, caus- a relatively slow entry into the central nervous system
ing worsening hypoxia. Therefore, preoxygenation can (up to 10 minutes) when compared with etomidate and
be further optimized by leaving the patient in the upright ketamine (2 to 3 minutes) and may cause hypotension in
position until just before unconsciousness is induced.14 the critically ill, making this drug a less desirable induc-
Consideration for nasal cannula apneic oxygenation for tion agent.17,18
obese patients may be helpful to extend the time prior to Succinylcholine is the most commonly used agent
desaturation during direct laryngoscopy, and, theoreti- for neuromuscular blockade during rapid sequence
cally, it is an inexpensive method that could be used for intubation (RSI), owing to its rapid onset of action and
all critically ill patients.15 its relatively short duration of action. In patients with
known hyperkalemia or in conditions where the ace-
tylcholine receptor is upregulated, such as spinal cord
PHARMACOLOGY injuries, stroke, neuromuscular disorders, myopathies,
and burns, a life-threatening increase in the serum potas-
Laryngoscopy and tracheal intubation can cause a number sium level may occur after the administration of suc-
of physiologic responses that can be particularly harmful cinylcholine. Rocuronium does not cause a significant
in the critically ill, including hypertension, tachycardia, hyperkalemic response and when given at a dose of
and increased intracranial pressure. The ideal induction 1 mg per kg, has a rapid onset of action and provides
agent would rapidly cause unconsciousness and amnesia, acceptable intubating conditions but a prolonged recovery
prevent the adverse physiologic responses to intuba- (45 to 60 minutes).19
tion, maintain stable hemodynamics and cerebral perfu-
sion, and provide excellent conditions for laryngoscopy.
Unfortunately, none of the available agents meet all of APPROACH TO THE AIRWAY
these criteria, and the anticipated response to tracheal
intubation, as well an understanding of the side-effect In patients who are completely unconscious, intuba-
profile of different induction agents, will dictate which tion often can be attempted without the use of induc-
medications are to be used. tion agents or neuromuscular blockers. Otherwise, a
Etomidate has rapid onset of action, no direct effects more deliberate plan should be developed as time permits
on vasomotor tone, does not cause an elevation in intra- (Fig. 49-2). The importance of first pass intubation suc-
cranial pressure, and generally provides excellent intu- cess cannot be overemphasized: more than two attempts
bation conditions, which explains its widespread use in at intubation has been associated with an increased risk
the critically ill. Etomidate causes sympatholysis and of major complications in the critically ill.20 Furthermore,
DESIGN SERVICES OF

Preoxygenation1
1
Improving preoxygenation:
- Keep head of bed elevated
- Avoid prolonging preoxygenation if O2 Predict difficult intubation2
saturation is in the mid to high 90s
- Consider NIPPV or assist with BMV if O2
saturation ⬍93% on high flow O2 No Yes
2Predicting difficult intubation in the

critically ill: RSI3 BMV predicted difficult?4
- Evidence of upper airway obstruction
- Blood, secretions, or vomit in airway
Successful? No Yes
3Consider use of accessory devices to
improve RSI if difficulty anticipated:
Videolaryngoscope Yes No Call for help, consider awake
Airtraq technique5
Fastrach
Confirm BMV/call for help
4Predicting Successful?
difficult BMV in
critically ill:
Evaluate for Ventilation adequate?
- Bronchospasm
post-intubation
- Poor lung/thoracoabdominal
complications6 No Yes
compliance
Yes No
5Limitations of awake technique:
- View through fiberoptic scope
2 intubation Rescue techniques7 Confirm
obscured by blood or vomit
attempts performed? and call for help
- Requires patient cooperation
- Time consuming
6Treatment
No Yes Assess for post-
of hypotension
intubation
- Fluid boluses, vasopressors
complications6
- Avoid hyperventilation
Treatment of hypoxia Repeat attempts8
- Increase FiO2 Ventilation adequate?
- Elevate head of bed
- Increase PEEP
No Yes
7Rescue techniques:
- LMA
Surgical Arrange necessary
- Fastrach
airway personnel/equipment to
secure definitive airway
8
Guidelines for repeat laryngoscopy
attempts:
- Second attempt by more experienced
provider and/or alternative technique
F I GUR E 4 9 -2 Approach to airway management in the conscious, critically ill. Abbreviations: NIVPPV, non-invasive positive
pressure ventilation; RSI, rapid sequence intubation, BMV, bag mask ventilation; LMA, laryngeal mask airway; PEEP, positive end
expiratory pressure.
mask ventilation after failed attempts at intubation may critically ill patients.21–24 The specific device used in cases
be difficult in patients with respiratory failure due to poor of difficult intubation will depend on the clinical circum-
lung compliance and may cause gastric insufflation and stances, operator experience, and equipment available at
regurgitation in nonfasted patients. RSI may reduce the different institutions. It bears mentioning that a single
risk of regurgitation and aspiration, improve intubating approach will not be effective in all circumstances, and
conditions, and allow for easier insertion of accessory and clinicians should be familiar with different devices and
rescue devices, making it the technique of choice for many techniques that can be used in different situations. After
DESIGN SERVICES OF

CHAPTER 49 ■ AIRWAY MANAGEMENT IN CRITICAL CARE MEDICINE 355
a failed attempt at intubation, the next attempt should endotracheal tube. Although some degree of laryngeal
involve a more experienced provider or an alternative edema occurs in most patients after tracheal intubation,
technique or device rather than repeating the same failed only a small percentage develop clinically significant air-
approach and expecting a different result. way obstruction after extubation. The absence of a “cuff
leak,” or a lack of air freely passing around a deflated
endotracheal tube, can help confirm the diagnosis of
COMPLICATIONS laryngeal edema prior to extubation. If laryngeal edema
is suspected, the patient should be treated with glucocor-
The critically ill have higher complication rates than ticoids for 24 hours prior to extubation. Extubating the
a patient undergoing elective intubation, and two of patient over an exchange catheter can often help facilitate
the most common complications are hypotension and reintubation if necessary.
hypoxia. Postintubation hypotension can occur for a Most patients who are reintubated for postextubation
number of reasons. Positive intrathoracic pressure from laryngeal edema typically develop symptoms within the
mechanical ventilation will cause a decrease in preload in first 30 minutes after extubation. Severe laryngeal edema
hypovolemic patients, resulting in hypotension. In hypo- is generally characterized by stridor and respiratory dis-
volemic patients, adequate intravenous access should be tress. Initial treatment involves intravenous glucocorti-
obtained and fluid boluses started prior to intubation if coids and nebulized epinephrine. Although only 1% to 4%
time permits. In patients with vasodilatory shock (eg, of patients extubated in the ICU will require reintubation
sepsis or anaphylaxis), the administration of an induction due to laryngeal edema, securing the airway may prove
agent may reduce the patient’s compensatory sympathetic difficult.26 Reintubation should be performed early before
tone and cause vasodilation, resulting in cardiovascular the airway becomes completely obstructed and intubation
collapse. In this case, hypotension can be avoided by using becomes impossible. We recommend the use of fiberop-
a lower dose of induction agent or with the use of vaso- tic or optic guidance in a spontaneously breathing patient
pressor agents. Hypotension may also result from hyper- whenever possible. If attempts fail, a surgical approach
ventilation. After intubation, the patient is often “bagged” will be necessary.
vigorously in a well-intentioned attempt to improve the
oxygen saturation or to correct acidosis. Particularly in
patients with exacerbations of chronic obstructive pulmo- REFERENCES
nary disease or asthma, hyperventilation can lead to air 1. Jaber S, Amraoui J, Lefrant JY, et al. Clinical practice and
trapping, increased intrathoracic pressure, and decreased risk factors for immediate complications of endotracheal
venous return to the heart, thus resulting in hypotension intubation in the intensive care unit: a prospective, multi-
and ultimately cardiac arrest.25 A brief pause in ventila- ple-center study. Crit Care Med. 2006;34(9):2355–2361.
tion (30 seconds), which allows the patient to fully exhale, 2. Griesdale DE, Bosma TL, Kurth T, et al. Complications of
may help to remedy the situation. endotracheal intubation in the critically ill. Intensive Care
Hypoxia is common after intubation in the criti- Med. 2008;34(10):1835–1842.
cally ill. The critically ill have poor physiologic reserve 3. Needham DM, Thompson DA, Holzmueller CG, et al. A
and undergo oxygen desaturation much more rapidly system factors analysis of airway events from the Intensive
Care Unit Safety Reporting System (ICUSRS). Crit Care
than those with normal cardiopulmonary function dur-
Med. 2004;32(11):2227–2233.
ing periods of apnea. In addition, patients with refractory
4. Shearn D, DeVita MA. Specialized response teams for spe-
hypoxia prior to intubation often develop atelectasis when cialized critical needs. In: DeVita MA, Hillman K, Bellomo R,
placed in the supine position and sedated and paralyzed, eds. Textbook of Rapid Response Systems. Germany: Springer
causing worsening hypoxia. Measures to improve pos- Verlag; 2011.
tintubation hypoxia include elevating the head of the bed 5. Schmidt UH, Kumwilaisak K, Bittner E, et al. Effects of
from the supine position, using higher levels of FiO2, and supervision by attending anesthesiologists on complica-
the application of increasing levels of positive end expira- tions of emergency tracheal intubation. Anesthesiology.
tory pressure. 2008;109(6):973–977.
6. American Society of Anesthesiologists Task Force on
Management of the Difficult Airway. Practice guidelines
for management of the difficult airway: an updated report
SPECIFIC CLINICAL CONDITION: by the American Society of Anesthesiologists Task Force
on Management of the Difficult Airway. Anesthesiology.
POSTEXTUBATION LARYNGEAL EDEMA 2003;98(5):1269–1277.
7. Oliwas N, Mort T. National ICU difficult airway survey:
Laryngeal edema is a common cause of upper airway preliminary results. Anesthesiology. 2003;99:403A.
obstruction in ICU patients. The condition results from 8. DeVita MA, Braithwaite RS, Mahidhara R, et al. Use of med-
trauma to the larynx and supraglottic tissue during ical emergency team (MET) responses to reduce hospital
intubation and from pressure and ischemia from the cardiac arrests. Qual Saf Healthcare. 2004;13:251–254.
DESIGN SERVICES OF

9. Soyuncu S, Eken C, Cete Y, et al. Determination of diffi- represent the best choice of induction agent? Anaesthesia.
cult intubation in the ED. Am J Emerg Med. 2009;27(8): 2009;64(5):532–539.
905–910. 18. Choi YF, Wong TW, Lau CC. Midazolam is more likely to
10. Levitan RM, Everett WW, Ochroch EA. Limitations of dif- cause hypotension than etomidate in emergency department
ficult airway prediction in patients intubated in the emer- rapid sequence intubation. Emerg Med J. 2004;21(6):
gency department. Ann Emerg Med. 2004;44(4):307–313. 700–702. PMCID: 1726487.
11. Benumof JL, Dagg R, Benumof R. Critical hemoglobin 19. Kirkegaard-Nielsen H, Caldwell JE, Berry PD. Rapid tra-
desaturation will occur before return to an unparalyzed cheal intubation with rocuronium: a probability approach
state following 1 mg/kg intravenous succinylcholine. to determining dose. Anesthesiology. 1999;91(1):131–136.
Anesthesiology. 1997;87(4):979–982. 20. Mort TC. Emergency tracheal intubation: complications
12. Mort TC, Waberski BH, Clive J. Extending the preoxygen- associated with repeated laryngoscopic attempts. Anesth
ation period from 4 to 8 mins in critically ill patients under- Analg. 2004;99(2):607–613, table of contents.
going emergency intubation. Crit Care Med. 2009;37(1): 21. Li J, Murphy-Lavoie H, Bugas C, et al. Complications of
68–71. emergency intubation with and without paralysis. Am J
13. Baillard C, Fosse JP, Sebbane M, et al. Noninvasive ventila- Emerg Med. 1999;17(2):141–143.
tion improves preoxygenation before intubation of hypoxic 22. Naguib M, Samarkandi A, Riad W, et al. Optimal dose of suc-
patients. Am J Respir Crit Care Med. 2006;174(2):171–177. cinylcholine revisited. Anesthesiology. 2003;99(5):1045–1049.
14. Dixon BJ, Dixon JB, Carden JR, et al. Preoxygenation is 23. Bozeman WP, Kleiner DM, Huggett V. A comparison of
more effective in the 25 degrees head-up position than in rapid-sequence intubation and etomidate-only intubation
the supine position in severely obese patients: a randomized in the prehospital air medical setting. Prehosp Emerg Care.
controlled study. Anesthesiology. 2005;102(6):1110–1115; 2006;10(1):8–13.
discussion 5A. 24. Dronen SC, Merigian KS, Hedges JR, et al. A comparison
15. Ramachandran SK, Cosnowski A, Shanks A, et al. Apneic of blind nasotracheal and succinylcholine-assisted intuba-
oxygenation during prolonged laryngoscopy in obese tion in the poisoned patient. Ann Emerg Med. 1987;16(6):
patients: a randomized, controlled trial of nasal oxygen 650–652.
administration. J Clin Anesth. 2010;22:164–168. 25. Adhiyaman V, Adhiyaman S, Sundaram R. The Lazarus
16. Jabre P, Combes X, Lapostolle F, et al. Etomidate ver- phenomenon. J R Soc Med. 2007;100(12):552–557.
sus ketamine for rapid sequence intubation in acutely ill 26. Wittekamp BH, van Mook WN, Tjan DH, et al. Clinical
patients: a multicentre randomised controlled trial. Lancet. review: post-extubation laryngeal edema and extubation fail-
2009;374(9686):293–300. ure in critically ill adult patients. Crit Care. 2009;13(6):233.
17. Morris C, Perris A, Klein J, et al. Anaesthesia in haemody- PMCID: 2811912.
namically compromised emergency patients: does ketamine
DESIGN SERVICES OF

CHAPTER
Airway Management in
Emergency Medicine
50 cn
Paul Phrampus and Sarah Parker
INTRODUCTION recent esophageal anastomosis. However, in patients

with chronic obstructive pulmonary disease (COPD),
Airway management is a critical aspect of the practice of asthma, hypoxemic respiratory failure, or cardiogenic
emergency medicine and the emergency department (ED) and noncardiogenic pulmonary edema without the above
presents a unique and challenging environment for airway contraindications, it can be a useful adjunct to prevent-
management. The undifferentiated nature of the patients ing intubation. A Cochrane database review of 14 studies
demands proficiency on the part of the clinician as well as showed that the use of noninvasive positive- pressure ven-
familiarity with a wide range of equipment and procedures tilation in patients with COPD decreased mortality, need
as well as adherence to best practices that have been iden- for intubation, respiratory rate, length of hospital stay, and
tified for emergency airway management. complications with treatment.2
SETTING AIRWAY ASSESSMENT

Patients arriving at the ED in extremis are often unan- When intubation is deemed necessary in the ED, it is pru-
nounced and many times have little accompanying history dent to decide that every airway is going to be a difficult air-
or clinical information. This challenge is quite different way and plan accordingly (see Chapter 12). It is estimated
from the elective surgical patient from whom a complete that up to 20% of ED intubations can be classified as diffi-
history can be acquired and a physical examination can be cult.3 Unlike the operating room, there is often no time to
conducted in a low-stress environment to develop a plan do an adequate physical examination of the emergency air-
for operative airway management. way, and patient history can be limited. A rapid examina-
In an ED one of the primary issues when evaluating tion of the head and neck can help to show characteristics
a patient is the decision to intubate. Clinical indications that can be suggestive of a difficult airway. Many patients
requiring emergency airway management are diverse but necessitating an emergency airway have decreased level of
revolve around the need to protect the airway of the pa- consciousness and are unable to assist with the examina-
tient who is otherwise unable to maintain a patent airway, tion, such as assessing the size of the mouth opening and
or to provide invasive positive- pressure oxygenation, ven- flexibility of the neck. In addition, patients can be limited
tilation, or both to the critically ill. to the prone position. In a retrospective review of ED intu-
Patients presenting with pathology such as allergic bations, Levitan et al concluded that in only one-third of
reactions, respiratory distress, cardiac arrest, burns, de- patients could a Mallampati score, thyromental distance,
creased levels of consciousness, and multisystems trau- and neck mobility be properly assessed.4 However, other
matic injury are common in the nearly 120 million ED anatomic abnormalities, including short neck, small chin,
visits that occur annually in the United States alone. It obesity, facial trauma, presence of facial hair, and neck
is estimated that 67% of intubations are performed for scars can be assessed in predicting the degree of difficulty
medical emergencies and 26% for traumatic emergencies in establishing bag mask ventilation and in performing
(Fig. 50-1).1 direct laryngoscopy (Fig. 50-2).
Select populations of patients are candidates for non- Unlike the routine preparations for cases of
invasive positive- pressure ventilation (see Chapter 3). elective intubations, patients presenting to the ED must
This technology is contraindicated in patients who are be presumed to have a full stomach. This fact requires
unable to protect their airway, have a cardiac arrest, the emergency physician to consider the risks of gastric
severely impaired consciousness, facial deformities sec- content aspiration into the management of airways in
ondary to trauma or surgery, high aspiration risk, and the ED.
357

F I GUR E 5 0 -1 A patient who was intubated

in the trauma resuscitation area requiring
maintenance of cervical spine precautions.
F I GUR E 5 0 -2 Intubating a patient in the ED

with a videolaryngoscope. The patient had a
large head, short neck, decreased thyromental
distance, and a difficult to palpate cricothyroid
membrane.

CHAPTER 50 ■ AIRWAY MANAGEMENT IN EMERGENCY MEDICINE 359
FIG U RE 50-3 A trauma patient arrives at

the ED after failed intubation in the field where
prehospital care providers placed a King LT
(laryngeal tube) airway.
Initial ED management of the airway included blind Given the emergent need for airway management,
nasal tracheal intubations. However, in the 1980s, Dronen coupled with the many limitations faced by the emergency
et al performed a prospective randomized control trial of physician, including limited patient history, cervical spine
blind nasal tracheal intubation versus rapid sequence in- immobilization, facial trauma, and presumed full stomach,
duction and endotracheal intubation in the ED setting. He it is imperative to always have a backup plan if the first at-
showed that rapid sequence intubation was more success- tempt at intubation fails. A multicenter report of emergency
ful (100% vs 65%), required less attempts (1.3 vs 3.7), was intubations suggests that 95% of intubations are success-
faster (64 vs 276seconds), and had fewer complications. ful the first time in the ED, and intubation is ultimately
Since that time, rapid sequence induction has been recog- 99% successful.1,6 In addition to standard laryngoscopy
nized as the safest, most efficient choice for ED intuba- equipment, most EDs have a difficult airway cart that is
tions.5 This technique uses a combination of sedative and stocked with airway stylets/bougies, laryngeal mask airways
muscle relaxants with a rapid onset and short half-life that (LMAs), intubating LMAs, esophageal-tracheal Combitubes
creates a favorable physiologic situation to facilitate endo- (Tyco-Kendall, Mansfield, Massachusetts, USA) or other
tracheal intubation via direct laryngoscopy (see Chapter 8). supraglottic rescue devices (such as the King airway, King
Systems, Noblesville, Indiana, USA), and a cricothyrotomy
EQUIPMENT kit. In the prehospital setting, LMAs/Combitubes/King air-
ways are frequently used when standard endotracheal intu-
Multisystem trauma patients are another category of air- bation fails, with success rates of ventilation approximating
way challenges unique to the ED. Distortions of normal 100%, negating the need for a surgical airway in the field
anatomy from swelling, bony or soft tissue injury along (Fig. 50-3). Of the patients who survive to hospital admis-
with bleeding, burns, foreign bodies, and vomiting can sion and for whom follow-up data is available, 40% require
occur. In addition, all trauma patients are presumed to emergent tracheostomy for definitive airway placement.7
have a cervical spine injury and require strict spinal im- However, in ED airway management, adjuncts are rarely
mobilization precautions. Cervical spinal immobilization deployed as rescue devices.8 A surgical airway is performed
prevents the ideal positioning of the patient for direct in only 0.84% of all cases and 1.7% of trauma cases.1 It is be-
laryngoscopy, and thus such cases should be automati- lieved the decline in rescue techniques and surgical airways
cally regarded as a potential for a difficult airway or at are secondary to the success of rapid sequence intubation.
a minimum a difficult laryngoscopy. Such a trauma pa-
tient requiring endotracheal intubation must be handled
in a way that reduces or eliminates potential movement
of the cervical spine. New technology, such as videolaryn- REFERENCES
goscopy (see Chapter 24), which includes the GlideScope
1. Walls RM, Brown CA III, Bair AE, et al. Emergency Airway
(Verathon Inc, Bothell, Washington, USA) and Storz C-mac Management: A Multi-center Report of 8937 Emergency
(Karl Storz & Company, Tuttlingen, Germany) devices, Department Intubations. J Emerg Med. 2010 Nov 28.
has become a very useful adjunct in trauma airways. With 2. Ram FS, Picot J, Lightowler J. Non-invasive positive pres-
limited mobility of the neck, videolaryngoscopy provides sure ventilation for treatment of respiratory failure due to
a more anterior view than direct laryngoscopy, which can exacerbations of chronic obstructive pulmonary disease.
facilitate endotracheal tube placement. Cochrane Database Syst Rev. 2004;(3):CD004104.

3. Murphy M, Walls RM. Identification of the difficult and 6. Sakles JC, Laurin EG, Rantapaa AA, et al. Airway manage-
failed airway. In: Walls R, ed. Manual of Emergency Airway ment in the emergency department: a one-year study of
Management. Philadelphia, PA: Lippincott Williams & 610 intubations. Ann Emerg Med. 1998;31(3):325–332.
Wilkins; 2004:70. 7. Guyette FX, Wang H, Cole JS. King airway use by air medi-
4. Levitan RM, Everett WW, Ochroch EA. Limitations of dif- cal providers. Prehosp Emerg Care. 2007;11(4):473–476.
ficult airway prediction in patients intubated in the emer- 8. Bair AE, Filbin MR, Kukarni RG, et al. The failed intuba-
gency department. Ann Emerg Med. 2004;44(4):307–313. tion attempt in the emergency department: analysis of
5. Dronen SC, Marigian KS, Hedges JR, et al. A comparison prevalence, rescue techniques, and personnel. J Emerg Med.
of blind nastotracheal and succinylcholine-assisted intuba- 2002;23(3):325.
tion in the poisoned patient. Ann Emerg Med. 1987;16(6):
650–652.

PART
Common Patient Conditions Requiring
XV Specialized Approach to the Airway
CHAPTER
Obstructive Sleep Apnea

and Airway Management
51 cn
Audra Webber and Kathirvel Subramanian
O bstructive sleep apnea (OSA) is a sleep disorder1

characterized by a decrease in upper airway patency
and size during sleep. Patients with OSA experience re-
adenoids is generally definitive therapy in this population.
However, obese children can still be at risk for OSA even
after adenotonsillectomy.4
peated instances of partial or complete airway obstruction Clinicians with a responsibility for airway manage-
that results in sleep disruption, hypercapnia, and hypox- ment are most likely to encounter a child with OSA when
emia. OSA can lead to numerous comorbidities, including he/she presents for adenotonsillectomy. However, one
hypertension (HTN), arrhythmias, and gastroesophageal may be required to care for a child with undiagnosed OSA
reflux disease (GERD). Additionally, the increased sym- in other settings as well, including other operative proce-
pathetic output and tone experienced by these patients2 dures. Hence, for elective pediatric procedures requiring
can contribute to the metabolic syndrome. OSA occurs in sedation or airway management, a thorough airway exam-
both children and adults but varies by etiology in these ination and questioning about nighttime snoring are war-
two groups. ranted. Snoring is a sensitive marker for OSA in children.
The gold standard of OSA diagnosis is polysomnog- Pediatric patients have very little oxygen reserve at base-
raphy, from which is derived the apnea-hypopnea index line and patients with OSA even less so. Preoxygenation is
(number of breathing cessations and partial obstructions one of the key strategies for a safe induction of anesthesia
per hour of sleep). The severity of OSA, (mild, moder- (Table 51-2). In pediatric patients with adenotonsillar hy-
ate, or severe) is based upon this index. This diagnostic pertrophy and therefore suspected OSA, it has been shown
scheme applies to both children and adults. that lateral positioning in combination with chin lift and
jaw thrust provide improved airway patency for anesthe-
tized children.5
PEDIATRIC OSA
The incidence of sleep apnea in the pediatric patient popu- ADULT OSA
lation is approximately 1% to 3%. The most common level
of obstruction of the airway during rest is at the base of OSA is far more common in adults than in children
the tongue and soft palate.3 OSA in children is most com- (Figs. 51-1–51-11). This disorder has an incidence in the
monly associated with enlarged tonsils and adenoids. The adult population of approximately 1 in 4 men and 1 in
degree of hypertrophy does not correspond clinically with 10 women.6 Only a small percentage of these patients carry
the severity of OSA. However, OSA is a multifactorial dis- an official polysomnographic diagnosis of OSA. Most of
order and is also associated with craniofacial anomalies as the adults with OSA are undiagnosed. Therefore, the un-
well as syndromes that cause decreased pharyngeal tone diagnosed OSA patient will be the one most frequently
such as Down Syndrome.4 Shwengel et al,4 in a review, encountered preoperatively. In the perioperative setting,
describe the pediatric OSA patient population as having these patients will present for all types of surgery, not
a peak at 2 to 6 years of age, no gender predominance, solely airway surgery. In the elective situation, a high index
and a weak association with obesity in decades past. of suspicion for OSA will serve the clinician well, as well
However, with childhood obesity on the rise, the associa- as the judicious use of OSA-specific questionnaires. OSA
tion of pediatric OSA with obesity has grown. There are is strongly associated with obesity, and the more obese
numerous physiologic consequences of OSA in children the patient the more likely the incidence of OSA. Obesity
(Table 51-1). Surgical excision of the enlarged tonsils and results in fatty deposits in the tongue and upper airway,
361

362 PART XV ■ COMMON PATIENT CONDITIONS REQUIRING SPECIALIZED APPROACH TO THE AIRWAY
which reduce lumen diameter and increase the likelihood maxilla.8 CT and MRI studies have shown OSA patients
of obstruction of the upper airway.6 There are anatomical have a smaller airway lumen than controls. Neck circum-
differences in the pharyngeal airway between OSA patients ference, male gender, and craniofacial anomalies also pre-
and controls. OSA patients have increased total fat volume dispose the patient to OSA (Table 51-3). Snoring is a very
surrounding the pharyngeal airway and greater airway sensitive but nonspecific indicator of OSA.
collapsibility.7 Additionally, nonobese OSA patients may In adults, OSA is associated with multiple morbidi-
have a shorter mandible, inferior hyoid, and retrognathic ties, and these are much more prevalent than in children.
These include cardiovascular disease, heart failure, ar-
Table 51-1 rhythmias, hypertension, cerebrovascular disease, meta-
bolic syndrome, and gastroesophageal reflux disease.
Consequences of OSA in the Pediatric
OSA patients can present unique difficulties to the
Population
anesthesiologist with regard to the induction of and emer-
1. Increased pharyngeal collapsibility gence from anesthesia (Table 51-4). During the periop-
erative period, numerous studies have demonstrated OSA
2. Increased likelihood of difficult airway
patients to have a potential for upper airway collapse,
3. Increased sensitivity to opioids exacerbation of hypoxemia and hypercapnia, cardiac ar-
4. Decreased response to hypercarbia and negative rhythmia and difficulty with airway management.9 These
pressure patients are more susceptible to anxiolytics, sedatives, and
5. Pulmonary HTN opioids as well as to general anesthetic agents. There is a
6. Cardiac dysfunction that may eventually lead to dose-dependent depression of muscle activity in the nor-
corpulmonale mal upper airway with IV sedative and inhaled anesthetic
7. Impaired growth, possibly due to increased work of agents that results in increased collapsibility. This effect
breathing is enhanced and even exaggerated in patients with OSA.9
Therefore, relatively small doses of sedation may rapidly
From Schwengel DA, Sterni LM, Tunkel DE, et al. Perioperative man-
result in apnea in this population. There is some evidence
agement of children with obstructive sleep apnea. Anesth Analg. for use of continuous positive airway pressure (CPAP)
2009;109(1):60–75 with permission. obviating the enhanced effects of sedation and opioid
Table 51-2
Perioperative Issues and Strategies in Pediatric OSA Patients
1. Adequate preoxygenation should be administered in a spontaneously breathing patient before induction of

anesthesia.
2. Inhaled induction with a volatile agent relaxes the genioglossus muscle and may result in airway collapse and
obstruction in the OSA patient. Consider:
a. Position lateral or upright
b. Jaw thrust
c. Positive pressure by mask
d. Oral airway
3. Sedatives should be given sparingly, and always under monitored care—consider nonsedating medications
such as ketamine or dexmedetomidine.
4. IV induction may be preferred in severe OSA patients to avoid upper airway obstruction during spontaneous
ventilation in the anesthetized patient.
5. Alternative means of managing the airway should be available for emergent situations, when ventilation or
intubation is impossible, as per the ASA Difficult Airway Algorithm.
6. If airway swelling is anticipated, intravenous steroids should be administered.
7. Extubation should occur only after the patient is fully awake.
8. A nasopharyngeal airway may be placed prior to extubation.
9. Supplemental oxygen should be used during any time that the patient is sedated.
From Schwengel DA, Sterni LM, Tunkel DE, et al. Perioperative management of children with obstructive sleep apnea. Anesth Analg. 2009;109(1):
60–75 with permission.

CHAPTER 51 ■ OBSTRUCTIVE SLEEP APNEA AND AIRWAY MANAGEMENT 363
FIG U RE 51-1 Three-dimensional magnetic

resonance imaging reconstructions of subjects
with (A, B) positional obstructive sleep apnea
syndrome (OSAS); C, D: nonpositional OSAS;
and E, F: control subjects. A, C, E: Lateral
pharyngeal wall, tongue, and pharyngeal airway
with outline of the face, posterosuperior view;
B, D, F: lateral pharyngeal wall, tongue, and
craniofacial structures (mandible and lower
part of maxilla), anterosuperior left oblique
view. Green, lateral pharyngeal wall; red,
tongue; yellow, upper airway space; blue web,
craniofacial structures. Note that positional
OSAS had relatively small volume of the lateral
pharyngeal wall and the smallest craniofacial
volume; nonpositional OSAS had relatively large
craniofacial volume and the largest volume of
the lateral pharyngeal wall; the control subjects
had the largest craniofacial volume and the
smallest volume of the lateral pharyngeal wall.
From Saigusa H, Suzuki M, Higurashi N,
et al. Three-dimensional morphological
analyses of positional dependence in patients
with obstructive sleep apnea syndrome.
Anesthesiology. 2009;110(4):885–890 with
permission.
Soft tissue Bony enclosure Airway size FIG U RE 51-2 Schematic explanations for interaction
between soft tissue surrounding the pharyngeal airway
and craniofacial bony enclosure. The airway size is
normal + determined by the balance between amount of soft
tissue and bony enclosure size. Ptissue, tissue pressure.
From Isono S. Obstructive sleep apnea of obese adults:
Ptissue pathophysiology and perioperative airway management.
Anesthesiology. 2009;110(4):908–921 with permission.
obesity
+
Ptissue
Small
maxilla and +
mandible

F I GUR E 5 1 -3 Pharyngeal airway lumen for

different degrees of OSA.
From Vos WG, De Backer WA, Verhulst SL.
Correlation between the severity of sleep apnea
and upper airway morphology in pediatric and
adult patients. Curr Opin Allergy Clin Immunol.
2010;10(1):26–33 with permission.
F I GUR E 5 1 -4 Three-dimensional reconstructed airway models before (A) and after (B) adenotonsillectomy. Axial velocity and
static pressure distributions, respectively, before (C and E) and after (D and F) surgery. Highest velocity and lowest wall static
pressure observed at the site of minimum cross-section in baseline (before) model. Surgery was found to increase the airway
cross-section in the retropalatal pharynx.
From Vos WG, De Backer WA, Verhulst SL. Correlation between the severity of sleep apnea and upper airway morphology in
pediatric and adult patients. Curr Opin Allergy Clin Immunol. 2010;10(1):26–33 with permission.

FIG U RE 51-5 A: Normal Bone 3D VR image

on the left with axial image through the
retroglossal airway on the left. Note that the
mandibular size is proportionate to the maxilla
and orbits. B: This woman had a thin body
habitus but had severe OSA. Note the recessed
and small hypoplastic mandible (arrow) and
marked narrowed retroglossal airway on the
axial image.
Image copyright David Solsberg, MD, PC. 2007.
All rights reserved. Used with permission.
FIG U RE 51-6 A: This patient has severe OSA

with retropalatal and retroglossal narrowing.
Note the narrowing of the transverse dimension
(double-ended arrow) of the retropalatal airway
(RP). The location of the tip of the palate (P)
and mildly narrow edretroglossal airway (RG)
is shown. The vallecula (V) is located at the
anterior aspect of the hypopharynx and the
piriform (P) sinuses are located posterolaterally.
B: Normal view for comparison.

F I GUR E 5 1 -7 A: Sagittal reformat view

shows the posterior displacement of the
enlarged tongue. The palate (P) is also long
and thickened contributing to narrowing of
the airway. B: VR-ACS view shows the marked
narrowing of the retroglossal airway even while
the patient was awake.
F I GUR E 5 1 -8 A: The soft tissues around

the retroglossal airway are circumferentially
thickened with resultant narrowing in this obese
patient with OSA. The airway is round rather
than the normal oval or rectangular shape.
B: Normal retroglossal airway for comparison.
The airway is more oval with patent lateral
recesses.
F I GUR E 5 1 -9 A: Severe retropalatal (RP)

airway narrowing measuring less than 30 mm2
posterior to palate (P). Patient has severe OSA
diagnosed by polysomnography. B: Normal RP
airway for comparison.
Image copyright David Solsberg, MD, PC. 2007

FIG U RE 51-10 A: Normal VR 3D Bone

side view. The maxilla and mandible are
proportionate to the upper face and skull.
B: Thin male with severe OSA. The maxilla and
mandible are recessed and retrognathic
(arrows). C: Sagittal reformat: Both the
retroglossal and retropalatal airways are narrow.
The tongue is too large for the mouth and
narrows the airway.
FIG U RE 51-11 OSA due to tracheal stenosis

(arrow) of intrathoracic trachea. A: Sagittal
reformat. B: VR-ACS. C: Axial view.

analgesia in OSA patients. Rennotte et al10 examined di- Chung11 reported that, in a group of unexpected difficult
agnosed OSA surgical patients whose nasal-CPAP was intubation patients referred for sleep studies postopera-
used until intubation and resumed immediately after ex- tively, 66% were diagnosed with OSA by polysomnog-
tubation, then used 24 to 48 hours postoperatively. These raphy. OSA is a risk factor for difficult mask ventilation
patients had no restrictions on analgesic, sedative, or anes- (MV)7 though no exact numbers are available. Mandibular
thetic drugs and experienced no complications. However, advancement7 without an oral airway is not effective in
more research is needed, and the efficacy of CPAP has not obese patients. The practitioner should always consider
yet been established for the perioperative setting.11 difficult or impossible MV in obese patients with OSA and
Patients with OSA are approximately eight times more have an oral airway at the ready.
likely to be difficult to intubate than those without this Those aspects of the patient airway that make one
disease.6 However, with proper positioning (ie, ramping) suspect the likelihood of difficult intubation are the same
this effect may be attenuated.12 In direct relation to this, as those that predispose patients to OSA (Table 51-3). A
patients who are difficult to intubate have a higher like- thorough airway examination is always warranted. This
lihood of being diagnosed with OSA. In a recent study, is especially important in patients with diagnosed and

Common Factors that Predispose to both Recommendations for Perioperative
OSA and Difficult Intubation or Ventilation Management of the Patient with OSA
Difficult 1. Extubate when fully awake

Predispoing Factors Airway OSA 2. Ensure full reversal of neuromuscular blockade
Obesity Yes Yes prior to extubation
Increased neck circumference Yes Yes 3. Extubation and recovery should be carried out in
lateral, semiupright, or other nonsupine position
Crowded oropharynx/high Yes Yes
Mallampati score 4. General anesthesia is preferable to deep sedation
for superficial procedures
Decreased neck extension Yes Yes
5. Oral or nasal airway or CPAP in nonnaïve patients
Limited mouth opening Yes Yes during sedation
Decreased thyromental distance/ Yes Yes 6. Consider postoperative respiratory compromise
mandibular hypoplasia when selecting perioperative medications. In this
regard, regional anesthesia, when compared with
From Seet E, Chung F. Management of sleep apnea in adults—functional intravenous opioids, reduces the likelihood of
algorithms for the perioperative period: continuing professional devel-
opment. Can J Anaesth. 2010;57(9):849–864 with permission.
adverse respiratory outcome
From American Society of Anesthesiologists. Practice guidelines for the

perioperative management of patients with obstructive sleep apnea. A
report by the ASA task force on perioperative management of patients
with OSA. Anesthesiology. 2006;104(5):1081–1092 with permission.
Table 51-4
Table 51-6
OSA: Perioperative Risks
Additional Airway Management Strategies
for the OSA Patient
1. Difficulty with intubation
2. Inability to tolerate supine position 1. Awake fiberoptic intubation
3. Rapid desaturation, even with adequate 2. GlideScope
preoxygenation due to reduced functional residual 3. Creation of a ramp for head-up positioning
capacity
4. Thorough preoxygenation/denitrogenation
4. Increased susceptibility to anesthestics and opioid
5. Availability of intubating LMA and other recommended
analgesics
devices for emergent airway management (as suggested
5. Postoperative somnolence and apneic episodes by the ASA Difficult Airway Algorithm, 2003)
6. Increased risk of postextubation obstruction 6. Properly sized oral and nasal airway placed prior to
and negative pressure pulmonary edema11 extubation

suspected OSA.6 In addition, as noted, the OSA patient 6. Seet E, Chung F. Management of sleep apnea in adults—
will more often present with difficult MV than other pa- functional algorithms for the perioperative period: continu-
tients. The clinician should therefore be prepared to use ing professional development. Can J Anaesth. 2010;57(9):
adjunctive airway devices or emergent ventilation devices, 849–864.
7. Isono S. Obstructive sleep apnea of obese adults: pathophysi-
such as the laryngeal mask airway. During spontaneous
ology and perioperative airway management. Anesthesiology.
ventilation preoxygenation, the OSA patient may benefit
2009;110(4):908–921.
from assistance with positive airway pressure provided by 8. Fogel RB, Malhotra A, White DP. Sleep. 2: pathophysiology
the anesthesiologist, or by his/her CPAP device,13 as well of obstructive sleep apnoea/hypopnoea syndrome. Thorax.
as an upright position for preoxygenation and emergence. 2004;59(2):159–163.
In 2006, the ASA developed practice guidelines14 for the 9. Chung F, Elsaid H. Screening for obstructive sleep apnea
perioperative management of patients with OSA or pre- before surgery: why is it important? Curr Opin Anaesthesiol.
sumptive OSA in the absence of a sleep study (Tables 51-5 2009;22(3):405–411.
and 51-6). 10. Rennotte MT, Baele P, Aubert G, et al. Nasal continuous
positive airway pressure in the perioperative management of
patients with obstructive sleep apnea submitted to surgery.
REFERENCES Chest. 1995;107(2):367–374.
11. Chung SA, Yuan H, Chung F. A systemic review of obstruc-
1. Yao FF, Malhotra V, Fontes ML, eds. Yao & Artusio’s tive sleep apnea and its implications for anesthesiologists.
Anesthesiology: Problem Oriented Patient Management. Anesth Analg. 2008;107(5):1543–1563.
6th ed. Philadelphia, PA: Lippincott Williams & 12. Neligan PJ, Porter S, Max B, et al. Obstructive sleep apnea
Wilkins;2007. is not a risk factor for difficult intubation in morbidly obese
2. Mickelson SA. Preoperative and postoperative management patients. Anesth Analg. 2009;109(4):1182–1186.
of obstructive sleep apnea patients. Otolaryngol Clin North 13. Arisaka H, Sakuraba S, Kobayashi R, et al. Perioperative
Am. 2007;40(4):877–889. management of obstructive sleep apnea with nasal con-
3. Barash PG, Cullen BF, Stoelting RK, et al, eds. Clinical tinuous positive airway pressure. Anesth Progr. 2008;55(4):
Anesthesiology. 6th ed. Philadelphia, PA: Lippincott 121–123.
Williams & Wilkins;2009. 14. American Society of Anesthesiologists. Practice guidelines
4. Schwengel DA, Sterni LM, Tunkel DE, et al. Perioperative for the perioperative management of patients with obstruc-
management of children with obstructive sleep apnea. tive sleep apnea. A report by the ASA task force on periop-
Anesth Analg. 2009;109(1):60–75. erative management of patients with OSA. Anesthesiology.
5. Arai YC, Fukunaga K, Ueda W, et al. The endoscopically 2006;104(5):1081–1092.
measured effects of airway maneuvers and the lateral
position on airway patency in anesthetized children with
adenotonsillar hypertrophy. Anesth Analg. 2005;100(4):
949–952.

CHAPTER
52 Morbid Obesity and

Bariatric Surgery
Kevin M. Hibbard and Shawn T. Beaman
A s the number of obese individuals in the United

States continues to rise, the likelihood of encoun-
tering morbidly obese patients in the operating room, as
increase in time to desaturation after 3 minutes of preoxy-
genation.3 These increases are thought to be a direct result
of increased FRC and an increase of oxygen reserve during
well as the number of bariatric procedures, will predict- the apneic period prior to intubation.
ably increase. Recent data has shown that 1 in 4 residents In addition to an increased amount of adipose tis-
of the United States are classified as obese, which has in- sue on their anterior chest, morbidly obese patients have
creased approximately 24% since 2000.1 The same study an increased amount of subcutaneous adipose tissue on
noted that individuals classified as morbidly obese, with their anterior and posterior neck leading to decreased an-
a BMI over 50, showed the greatest percentage increase terior mobility of pharyngeal structures and to decreased
of prevalence between 2000 and 2005, rising more than neck extension during laryngoscopy, respectively. Lastly,
50%.1 Data released in 2007 has shown that the number it has been shown that there is an increased amount of
of bariatric procedures performed in the United States was submucosal tissue in the oral cavity and pharynx of obese
expected to increase over 10-fold from 13,000 procedures patients. This increased tissue can result in an enlarged
in 1998 to 200,000 procedures in 2006, paralleling the tongue, increased size of the tonsillar pillars, and en-
significant rise in obese individuals.2 Management of croachment of the posterior pharyngeal wall into the pha-
the airway of obese patients often presents challenges to ryngeal space with an increase in both Mallampati class
the anesthesiologist while in the operating room. The in- and Cormack–Lehane grade view (see also Chapter 51).4
creased difficulty, secondary to increased soft tissue on the The body habitus, as opposed to the absolute weight of the
patient’s chest or in the airway, often complicates venti- patient, is a more predictive factor in determining the dif-
lation and/or laryngoscopy. In addition to the decreased ficulty with intubation and ventilation.4 An android body
chest wall and lung compliance that typically occurs dur- habitus with more abdominal adipose tissue, as opposed
ing general anesthesia, many bariatric procedures are per- to a gynecoid body habitus with more hip and buttock adi-
formed laparoscopically, which dictates the need for posi- pose tissue, will typically cause a greater decrease in lung
tive pressure ventilation via an endotracheal tube, with a compliance in the supine position secondary to increased
further reduction in compliance. For these reasons, it is pressure on the diaphragm during inspiration. This can
essential that all anesthesia providers become experts in lead to even less effective preoxygenation and increased
the management of the airway in obese patients. In gen- airway pressures during ventilation after that patient has
eral, much of the difficulty in securing the airway of a been intubated.
morbidly obese patient involves management of the ana- Recently, attention in the literature has focused on
tomic and physical challenges that are present secondary whether obese patients actually present an increased risk
to the increased amount of adipose tissue and its related of difficult ventilation or intubation. A study by Juvin
effects on the airway and lung volumes. et al5 in 2003 concluded that obese patients were more dif-
Although the exact definition is debatable, morbid obe- ficult to intubate as compared with nonobese patients. The
sity is commonly defined as a BMI greater than 40 kg per m2. authors reported an increase in multiple attempts at intu-
These patients typically manifest an increased amount of bation and a decreased Cormack–Lehane grade with direct
adipose tissue on their anterior chest, causing decreased laryngoscopy of obese patients.5 In contrast, the authors
chest wall and lung compliance. This results in a greatly re- of a recent study found that, after intubating 100 mor-
duced functional residual capacity (FRC), especially when bidly obese patients presenting for bariatric surgery, there
the patient is placed in the supine position. Positioning a was no relation between patient weight and difficulty with
patient in the head-elevated position (ie, ear aligned with intubation.6 In this investigation, only Mallampati class
sternal notch) as opposed to the supine position results and neck circumference were predictive of difficulty with
in a 23% increase in arterial oxygen tension and a 29% intubation.6 More recently, a study by Gonzalez et al,7
370

CHAPTER 52 ■ MORBID OBESITY AND BARIATRIC SURGERY 371
in which obese and nonobese patients were compared, by Dixon et al.3 In HELP, the patient’s head, chest, and
found that obese patients were several times more likely shoulders are elevated, with mild neck extension, thus im-
to have an intubating difficulty score greater than 5 proving alignment of the pharyngeal and laryngeal axes of
and were therefore classified as difficult to intubate. The the airway. Proper positioning aligns the patient’s sternum
authors further showed that a relationship exists between and external auditory meatus along an imaginary horizon-
difficulty of intubation in an obese patient and an in- tal line (Fig. 52-3).6 The technique is usually performed
creased neck circumference, or a Mallampati class of 3 by constructing a ramp of folded blankets on the operat-
or greater (Fig. 52-1). The exact neck circumference that ing room table prior to the patient transferring from the
would be predictive of a difficult airway is not precisely stretcher. This position also relieves excess weight on the
defined, but it is estimated to be greater than 46 cm or patient’s anterior neck during laryngoscopy and decreases
18 inches.7 These studies suggest that morbid obesity pressure on anterior chest and neck caused by the weight
does not, in and of itself, predispose a patient to having of excessively large breasts (Figs. 52-4 and 52-5). With
a difficult airway. However, physical characteristics that proper positioning, obese patients may be no more dif-
are more likely to be present in an obese patient, such as ficult to intubate than the average-sized patient.7
increased Mallampati class and increased neck circumfer- Several commercial devices and ramps have recently
ence, will likely result in such a patient having an airway been developed to assist the anesthesiologist in position-
that is difficult to intubate. ing the obese patient in the head-elevated position. One
Preparation is the most important step for managing product is a preformed foam ramp (Troop Elevation
any patient with a suspected difficult airway. This is Pillow, C&R Enterprises, Frisco, TX, USA) designed to
especially true when providing care to the morbidly obese be placed directly onto the operating room table to elevate
patient. A thorough and meticulous physical examination the head and shoulders of the patient while still providing
focused on the airway and respiratory systems should al- neck extension (Fig. 52-6). The Troop elevation pillow
ways be performed prior to transporting the patient to the can be positioned properly prior to and after induction
operating room. The anesthesia provider should pay spe- with greater speed and ease when compared with folded
cial attention to the patient’s ability to tolerate the supine blankets. It was also marketed as an alternative to the trial
position as reflected by oxygen saturation and respiratory and error method needed to properly align the patient
mechanics. When preparing for induction, the anesthesia using blankets. An alternative that may be commercially
provider should have various airway devices immediately available soon entails the use of an inflatable, multicham-
available in case of difficulty with mask ventilation or di- bered pillow to properly position the patient (Fig. 52-7).8
rect laryngoscopy. A proper selection includes equipment This pillow can be used to position the patient properly
necessary to intubate the trachea with fiberoptic bron- prior to induction, then deflated for the remainder of the
choscopy (see Chapter 23). Additional emergency equip- surgical procedure, negating the need to roll the patient
ment includes laryngeal mask airways of various sizes, an and remove blankets or a ramp prior to beginning the sur-
Eschmann stylet, specialized laryngoscope blades suited to gery. The device can subsequently be reinflated for opti-
handle increased pharyngeal soft tissue (such as a Bainton mal positioning prior to extubation.
blade, Fig. 52-2), and the apparatus necessary for transtra- Other methods for proper positioning of the obese
cheal jet ventilation. The presence of a second experienced patient involve the use of innovative operating room table
airway provider is also prudent. Because difficult airways adjustments prior to induction. The simplest technique
are often unpredictable, it is always appropriate to prepare involves a combination of the reverse Trendelenburg posi-
for the worst possible outcome when managing the airway tion and elevation of the patient’s head. A second method
of the obese patient. is the Whelan–Callicott position, which calls for a 30°
A key step in preparing to secure the airway of a reverse Trendelenburg position with the headpiece ex-
morbidly obese patient involves proper patient position- tended, without any supports behind the patient’s head.
ing. For reasons described above, it is of the utmost impor- This permits proper alignment of the sternum and the ex-
tance to position the patient properly prior to induction, ternal auditory meatus along a horizontal line.9 A third
to provide both the best possible preoxygenation, and to alternative requires flexion of the operating room table at
optimize direct laryngoscopy. The goal in positioning the the trunk-thigh hinge, while providing a degree of neck
obese patient is to decrease the compression of the pa- extension using the head piece, with the goal once again
tient’s thoracic cavity by anterior chest wall adipose tis- to align the sternum with the external auditory meatus.10
sue, while maintaining as much FRC as possible during Regardless of whether a morbidly obese patient is to
preoxygenation and induction. The most beneficial posi- undergo a bariatric procedure or any other type of pro-
tioning technique is an elevation of the chest and head, cedure the same steps should be employed to secure the
sometimes called the head-elevated laryngoscopic posi- patient’s airway. The most critical step involves using clin-
tion or HELP. HELP increases the effectiveness of preoxy- ical judgment as to whether the patient’s airway necessi-
genation and prolongs the interval before oxygen desatu- tates intubation using an awake fiberoptic approach. If a
ration occurs, the “desaturation safety period” described proper airway examination demonstrates that the patient

F I GUR E 5 2 -1 A supine morbidly obese female

with a BMI of 46 kg/m2, a Mallampati class three
airway, and a neck circumference greater than
50 cm.
F I GUR E 5 2 -2 The Bainton laryngoscope

blade, which has a tubular distal portion used to
increase visualization of the glottis in patients with
significantly increased pharyngeal soft tissue or
pharyngeal edema that would normally obstruct the
view of the airway. The Bainton blade can accept
endotracheal tubes up to size 8.0 through the
tubular portion with the adapter removed.
F I GUR E 5 2 -3 Obese male in the HELP position

with the head and shoulders elevated by stacked
folded operating room blankets. Notice the sternum
and external auditory meatus are aligned along a
horizontal line.

CHAPTER 52 ■ MORBID OBESITY AND BARIATRIC SURGERY 373
FIG U RE 52-4 Obese female in the supine

position with excessive anterior neck adipose
tissue.
FIG U RE 52-5 The same obese female

at a later date in the HELP position prior to
induction.
FIG U RE 52-6 The Troop elevation pillow

with normal operating room pillow resting on
top.
(Reused with permission from Ogunnaike BO,
Whitten CW. Anesthesia and obesity. In: Barash
PG, Cullen BF, Stoelting RK, et al, eds. Clinical
Anesthesia. 6th ed. Philadelphia, PA: Lippincott
Williams & Wilkins; 2009:1243.)

F I GUR E 5 2 -7 A multichambered inflation

device used for positioning the patient in the
HELP position. The ramp can be deflated and
remain in place during the procedure instead
of having to be removed prior to the operation.
(Reused with permission from Ogunnaike BO,
Whitten CW. Anesthesia and obesity. In: Barash
PG, Cullen BF, Stoelting RK, et al, eds. Clinical
Anesthesia. 6th ed. Philadelphia, PA: Lippincott
Williams & Wilkins; 2009:1243.)
may be safely intubated by direct laryngoscopy, it is of 4. Adams JP, Murphy PG. Obesity in anesthesia and intensive
great importance to have proper patient positioning prior care. Br J Anaesth. 2000;81:91–108.
to induction with the patient in the HELP position. Proper 5. Juvin P, Lavaunt E, Dupont H, et al. Difficult tracheal
emergency airway equipment should be immediately intubation is more common in obese than in lean patients.
Anesth Analg. 2003;97:595–600.
available in the operating room. It is also advised that
6. Brodsky JB, Lemmens HJM, Brock-Utne JG, et al. Morbid
a second experienced anesthesia provider be present in
obesity and tracheal intubation. Anesth Analg. 2002;94:
the operating room during induction for assistance if 732–736.
needed. In the case of an unanticipated difficult airway, 7. Gonzalez H, Minville V, Delanoue K, et al. The importance
the American Society of Anesthesiologists Difficult Airway of increased neck circumference to intubation difficulties in
Algorithm should be followed using either invasive or obese patients. Anesth Analg. 2008;106:1132–1136.
noninvasive techniques to provide adequate ventilation or 8. Nissen MD, Gayes JM. An inflatable multichambered
to intubate the patient.11 With proper patient positioning, upper body support for the placement of the obese patient
planning, and a thorough understanding of the influences in the head-elevated laryngoscopy position. Anesth Analg.
of excessive adipose tissue on the anatomy of the obese 2007;104:1305.
patient, the anesthesia provider should be able to manage 9. Zvara DA, Calicott RW, Whelan DM. Positioning for
intubation in morbidly obese patients. Anesth Analg.
this group of patients safely and competently.
2006;102:1592.
10. Rao SL, Kunselman AR, Schuler HG, et al. Laryngoscopy
and tracheal intubation in the head-elevated position in
REFERENCES obese patients: a randomized, controlled, equivalence trial.
Anesth Analg. 2008;107:1912–1918.
1. Sturm R. Increases in morbid obesity in the USA: 11. American Society of Anesthesiologists Task Force on the
2000–2005. Public Health. 2007;121:492–496. Management of the Difficult Airway. Practice guidelines for
2. Santry HP, Gillen DL, Lauderdale DS. Trends in bariatric the management of the difficult airway: an updated report
surgical procedures. JAMA. 2005;294:1909–1917. by the American Society of Anesthesiologists Task Force
3. Dixon BJ, Dixon JB, Carden JR, et al. Preoxygenation is on the Management of the Difficult Airway. Anesthesiology.
more effective in the 25 degrees head-up position than 2003;98:1269.
in the supine position in severely obese patients: a ran-
domized controlled study. Anesthesiology. 2005;102:
1110–1115.

CHAPTER
Obstetrics 53 cn
Kristin M. Ondecko Ligda and Manuel C. Vallejo
INTRODUCTION ● Enlarged breast tissue: Enlarged breast tissue, especially

in the supine parturient, can affect the practitioner’s abil-
Airway management of parturient patients presents a chal- ity to manipulate the laryngoscope and obtain adequate
lenge to the health care practitioner as two lives are being laryngeal views and alignment of the laryngeal, pharyn-
cared for at one time. Maternal complications such as fail- geal, and mouth axes during intubation.5
ure to maintain an airway can contribute to fetal morbidity ● Airway edema: Contributors to airway edema include
or even death. higher estrogen levels and increased blood volume.
In a review of the Centers for Disease Control and Comorbidities such as preeclampsia or respiratory infec-
Prevention Pregnancy-Related Mortality Surveillance System, tions may also contribute to airway edema. These all can
2.5% of maternal deaths were attributed to anesthesia, and lead to mucosal edema of the nares, tongue, oropharynx,
the most important cause (58%) of anesthesia-related mater- and larynx, in addition to engorgement of the capillary
nal mortality was failure to maintain the airway.1 Although beds with mucosal friability. Tongue enlargement may
there have been significant advancements in airway manage- also hinder adequate placement of the laryngoscope blade
ment technology such as the laryngeal mask airway and the into the mouth and larynx. Airway edema may make
GlideScope, and in the development of the American Society placement of the endotracheal tube challenging, if not
of Anesthesiologists (ASA) Difficult Airway Algorithm, the impossible.6–9 Hence, because of airway edema in the par-
obstetric patient continues to be at risk of failed intubation turient, the best laryngoscopic intubation attempt is often
when compared with the general population. the first attempt. Repeated attempts can often lead to fur-
During an evaluation of anesthesia-related maternal ther mucosal bleeding and subsequent intubation failure.
mortality between 1979 and 1990, general anesthesia pre- ● Risk of aspiration: The obstetric patient, due to increased
sented a greater risk of maternal mortality than regional levels of progesterone, experiences decreased lower esoph-
anesthesia. Maternal death occurred most frequently dur- ageal sphincter tone. The gravid uterus also contributes to
ing cesarean delivery (82% of deaths). Of these, 52% of increase in intragastric pressures and distorts the anatomy
deaths were the result of complications from general anes- of the lower esophageal sphincter, diaphragm, esophagus,
thesia, which were attributed to hypoxia, difficult or failed and stomach. These all can contribute to gastroesophageal
intubations, or pulmonary aspiration.2 reflux throughout pregnancy.10–12 Additionally, advanced
labor can contribute to delayed gastric emptying times.
Although pain is thought to contribute to the delay, the
delay in gastric emptying is still present even with an
PREGNANCY-RELATED ANATOMIC effective epidural anesthetic.13
AND PHYSIOLOGIC CHANGES ● Risk of hypoxia: Pregnancy induces changes to respiratory
mechanics and physiology. Pregnancy has not been shown
There are several pregnancy-related changes to the partu-
to change the FEV1, FEV1/FVC, flow-volume loops or
rient’s anatomy and physiology that places her at increased
closing capacity; however, pregnancy is known to increase
risk for airway management difficulties (Fig. 53-1).
diaphragmatic excursion and decrease chest wall excur-
● Weight gain: the average parturient gains approximately sion. The gravid uterus displaces the diaphragm, which
12 kg or 17% of her prepregnancy body weight as the contributes to a decrease in residual volume. Tidal vol-
result of an increase in the size of the uterus, placenta, and umes increase early in pregnancy, and increase up to 45%
fetus; an increase in blood and interstitial fluid volumes; from prepregnancy values, which leads to increased min-
and an increase in fat deposition.3 Increased body mass ute ventilation.14 Oxygen consumption increases in preg-
and obesity, in particular, increase the risk of the patient nancy due to the increased metabolic requirements of the
having a difficult airway and also the risk of emergency fetus and mother, alongside increases in carbon dioxide
cesarean delivery.4 production, further contributing to the increase in minute
375

F I GUR E 5 3 -1 The parturient’s increased weight gain,

enlarged breast tissue, airway edema, risk of hypoxia,
and risk of aspiration from the gravid uterus places her
at increased risk for airway management difficulties.
(Photo as originally included).
ventilation.15 Starting in the second trimester, the gravid anesthesia and usage of neuraxial anesthetic techniques
uterus displaces the diaphragm in the cephalad direction, are the most important contributors to the maternal mor-
which contributes to the decrease in the residual volume, tality decline.
expiratory reserve volume, and function residual capacity. However, risk factors still exist for aspiration pneu-
The functional residual capacity (FRC)is decreased nearly monitis that are based on the composition of the aspi-
20% by term.14–16 The FRC is further decreased in the rate (nonparticulate or liquid vs particulate), the pH of
supine position, along with decreased cardiac output sec- the fluid (pH less than 2.5 associated with higher risk),
ondary to aortocaval compression.17 The reduced FRC can and its volume (greater than 25 mL or 0. 4 mL/kg associ-
actually fall below closing capacity with resultant airway ated with higher risk).19 In addition to a decrease in lower
closure, leading to increased alveolar-arterial oxygen gradi- esophageal sphincter tone, difficult or failed intubation is
ent. Obesity also contributes to decreased FRC. Therefore, also associated with an aspiration risk in the peripartum-
because the parturient has an increased respiratory rate period.20 Interestingly, the risk of aspiration is also pres-
and lower FRC, the pregnant patient is at higher risk of ent upon extubation, just as upon intubation, and thus,
hypoxia and apnea compared with the normal adult. prophylactic measures should also cover the time frame of
emergence in addition to induction.
Those parturients who are scheduled for elective
ASPIRATION RISKS cesarean section should fast from solid and liquid foods
according to ASA guidelines. In addition, preoperative
Maternal morbidity due to pulmonary aspiration of gas- prophylactic measures given prior to induction of anes-
tric contents has decreased in recent decades due to the thesia to minimize the risk of aspiration include an oral
use of neuraxial anesthesia; antacids, histamine-receptor nonparticulate antacid, histamine (H2)-receptor antago-
antagonist, and/or proton pump inhibitors; rapid-sequence nist, proton pump inhibitors, and/or metoclopramide.21
induction for general anesthesia; and establishment of nil In emergency cesarean deliveries, oral nonparticulate
per os (NPO) recommendations.18 Avoidance of general antacid should be given when the patient is transferred
DESIGN SERVICES OF

CHAPTER 53 ■ OBSTETRICS 377
to the operating room, and if possible, the patient may be Prediction of the difficult parturient airway would
given intravenous H2-receptor antagonist or proton pump include the standard patient assessment including
inhibitor. For a woman in labor, studies have shown that Mallampati classification, thyromental distance, head
liberalized NPO policies, such as allowing water only or extension, mandibular protrusion, and identification of
eating during labor, did not improve obstetric outcomes cricothyroid membrane. In addition to the anatomic and
but did increase gastric residual volumes and volume of physiologic changes particular to the parturient, other
vomitus.22 characteristics of possible difficult airways include full
Cricoid pressure, or the Sellickmaneuver, can also be dentition, small mandible, limited mouth opening, limited
applied to minimize the aspiration risk during induction neck flexion or extension, short or thick neck, arched pal-
of general anesthesia. The goal is to apply pressure via the ate, and protruding incisors. Other comorbidities, such as
cricoids, the only solid ring in the larynx, on the esopha- rheumatoid arthritis or Arnold-Chiari malformations, may
gus to prevent stomach content regurgitation. Cricoid also contribute to airway difficulties.25
pressure is maintained until there is confirmation of the In select high-risk parturients, placement of a prophy-
placement of the endotracheal tube in the trachea and the lactic epidural catheter may be used to provide neuraxial
endotracheal tube cuff is inflated. anesthesia should an emergent cesarean delivery be nec-
To minimize the risk of aspiration, general anesthe- essary (Fig. 53-2). The epidural catheter could then be
sia in the parturient should be reserved for those who are activated when the active stage of labor is reached. As with
unable to receive a neuraxial anesthetic, such as patients any patient with an expected difficult airway, an awake
with elevated intracranial pressures or coagulopathies, or intubation should be performed to secure the airway.
for emergent cesarean deliveries (as in the case of uter- In addition, the same vigilance for the airway should be
ine rupture or severe fetal distress) for which aneuraxial maintained during extubation as during intubation.
anesthetic cannot be placed. In an unexpected difficult airway, use of the ASA’s
Difficult Airway Algorithm is important while maintain-
ing maternal and fetal oxygenation. When the patient is
DIFFICULT AIRWAY unable to be ventilated by mask, the laryngeal mask air-
way is the first line rescue device with needle cricothyrot-
The increased BMI combined with the pregnancy-related omy with transtracheal jet ventilation as an alternative.
changes to the airway place the parturient at increased risk
of difficult intubation. In the general population for surgery, Airway Management in Preparation for General
the rate of failed intubations is approximately 1 in 2,330; Anesthesia:
however, the incidence is nearly eight times more preva- ● Proper preparation of the operating room, including avail-
lent in the obstetric patient, occurring in 1 in 283 obstetric ability of laryngoscope blades, extra endotracheal tubes,
patients,23 despite advances in airway devices and educa- and suction is necessary. Ensure appropriate assessment
tional resources for practitioners such as the ASA Difficult of the patient, including airway examination, to recognize
Airway Algorithm. Although morbidity from failed intuba- potential difficult airways.
tions has also occurred, the mortality from failed intuba- ● Formulate plan for induction, intubation, maintenance of
tion was estimated to be 13 times higher in the obstetric anesthesia, emergence, and extubation with an alternative
population than the general population for surgery.24 plan in mind for each step.
FIG U RE 53-2 The modern emphasis on

regional anesthesia for labor and delivery, as
well as operative delivery, has led to significant
declines in maternal and fetal morbidity and
mortality related to airway management.
(Photo from Dr. Vallejo showing epidural
placement.)
DESIGN SERVICES OF

● Prior to induction of general anesthesia, aspiration prophy- 4. Hood DD, Dewan DM. Anesthetic and obstetric outcome
laxis with nonparticulate antacid should be administered in morbidly obese parturients. Anesthesiology. 1993;79:
to patients at high risk (ie, morbid obesity, known dif- 1210–1218.
ficult airway, and diabetes with gastroparesis); histamine 5. Munnur U, de Boisblanc B, Suresh MS. Airway problems in
pregnancy. Crit Care Med. 2005;33:S259–S268.
(H2)-receptor antagonist, proton pump inhibitors, and/or
6. Brimacombe J. Acute pharyngolaryngealoedema and pre-
metoclopramide may also be provided.
eclamptictoxaemia. Anaesth Intensive Care. 1992;20(1):
● The gravid uterus of the supine patient contributes to 97–98.
aortocaval compression, reducing blood flow to the heart 7. Jouppila R, Jouppila P, Hollmen A. Laryngeal edema as
and cardiac output. A wedge, either preformed or one an obstetric anesthesia complication: case reports. Acta
made from blankets, should be placed under the right Anaesthesiol Scand. 1980;24:97–98.
hip to facilitate the displacement of the uterus 30°, which 8. Ezri T, Szmuk P, Evron S, et al. Difficult airway in ob-
reduces the compression of the great vessels and improves stetric anesthesia: a review. Obstet Gynecol Surv. 2001;56:
uterine blood flow, as well as venous return to the heart. 631–641.
● Due to the decreased FRC, increased oxygen consump- 9. Leontic EA. Respiratory disease in pregnancy. Med Clin
tion, and decreased cardiac output, effective denitrogena- North Am. 1977;61:111–128.
10. Van Thiel DH, Gavaler JS, Stremple J. Lower esophageal
tion and preoxygenation are essential in the parturient.
sphincter pressure in women using sequential oral contra-
● Optimum positioning of the patient during preparation
ceptives. Gastroenterology. 1976;71:232–234.
maximizes successful laryngoscopy of the larynx and intu- 11. Van Thiel DH, Gavaler JS, Joshi SN, et al. Heartburn of
bation of the trachea. Methods to improve visualization pregnancy. Gastroeneterology. 1977;72:666–668.
during laryngoscopy include the following: 12. Carp H, Hayaram A, Stoll M. Ultrasound examination of
● Semi-upright positioning by raising the shoulders, neck, the stomach contents of parturients. Anesth Analg. 1992;74:
and head off the bed to align the ear with the sternal 683–687.
notch to maximize alignment of the pharyngeal, laryn- 13. Nimmo WS, Wilson J, Prescott LF. Further studies of
geal, and oral axes gastric emptying during labour. Anaesthesia. 1977;32:
● Using either a short-handled laryngoscope or a pediatric 100–101.
laryngoscope handle with an adult blade 14. Conklin KA. Maternal physiological adaptations dur-
● Positioning the breast tissue caudal and lateral by taping
ing gestation, labor and the puerperium. Semin Anesth.
1991;10:221–234.
the tissue or manual displacement from the airway field.
15. Norregaard O, Schultz P, Ostergaard, et al. Lung func-
● Prepare for rapid sequence induction of anesthesia with cri- tion and postural changes during pregnancy. Respir Med.
coid pressure applied until endotracheal tube cuff inflation 1989;83:467–470.
and confirmation of tube placement within the trachea. 16. Gee JB, Packer BS, Millen JE, et al. Pulmonary mechanics
● Maintain vigilance during extubation as the same risks of during pregnancy. J Clin Invest. 1967; 46:945–952.
airway edema, aspiration, and hypoxia exist during extu- 17. Alaily AB, Carrol KB. Pulmonary ventilation in pregnancy.
bation as were present during intubation. Consider the Br J Obstet Gynaecol. 1978; 85:518–524.
use of an airway exchange catheter to maintain a conduit 18. Lewis G, ed. Confidential Enquiry into Maternal and
to the trachea. Child Health (CEMAC). Saving Mothers’ Lives: Reviewing
(Maternal) Deaths to Make Motherhood Safer 2003–2005. The
Seventh Report on Confidential Enquiries into Maternal Deaths
CONCLUSION in the United Kingdom. London: CEMACH; 2007.
19. Awe WC, Fletcher WS, Jacob SW. The pathophysiology of
The pregnant patient presents a challenge to the health
aspiration pneumonitis. Surgery. 1966;60:232–239.
care practitioner. A thorough discussion and establish-
20. Gibbs CP, Rolbin SH, Norman P. Cause and prevention
ment of a plan with the obstetrician should be held for of maternal aspiration (letter). Anesthesiology. 1984;61:
each parturient. The principles outlined above will help to 111–112.
reduce morbidity to both the mother and the fetus related 21. American Society of Anesthesiologists Task Force on
to airway management. Obstetric Anesthesia. Practice guidelines for obstetric
anesthesia. Anesthesiology. 2007;106:843–863.
REFERENCES 22. O’Sullivan G, Liu B, Hart D, et al. A randomized controlled
trial to evaluate the effect of food intake during labour on
1. Berg CJ, Atrash HK, Koonin LM, et al. Pregnancy-related obstetric outcome. BMJ. 2009;338:b784.
mortality in the United States, 1987–1990. Obstet Gynecol. 23. Samsoon GL, Young JR. Difficult tracheal intubation: a
1996;88:161–167. retrospective study. Anaesthesia. 1987;42:487–490.
2. Hawkins JL, Koonin LM, Palmer SK, et al. Anesthesia- 24. Suresh MS. Difficult airway in the parturient. Probl Anesth.
related deaths during obstetric delivery in the United States, 2001;13:88–99.
1979–1990. Anesthesiology. 1997;86:277–284. 25. American Society of Anesthesiologists Task Force on
3. Spatling L, Fallenstein F, Hugh A, et al. The variability of Management of the Difficult Airway. Practice guidelines
cardiopulmonary adaptation to pregnancy at rest and dur- for management of the difficult airway. Anesthesiology.
ing exercise. Br J Obstet Gynaecol. 1992;99(suppl 8):1–40. 2003;98:1269–1277.
DESIGN SERVICES OF

PART
Care After Intubation
XVI
CHAPTER
Positive Pressure Ventilation 54 cn
Max Rohrbaugh and A. Murat
INTRODUCTION in the lungs that cannot be forcibly expelled during active

expiration. The total volume that remains in the lungs
As a guide to airway management, this book has so far after relaxed tidal expiration is the sum of ERV and RV
focused mainly on establishing a secure channel between and is called functional residual capacity (FRC). The total
the trachea or main bronchi and the outside world, usually volume that can be inspired from that point is the sum of
in the form of an endotracheal tube. This is a worthy goal VT and IRV and is called inspiratory capacity (IC). The
and a prerequisite for life for most people, but it remains total volume that a person can move in and out of the
a means to an end. After the tube is in place, we must do lungs at maximum effort is the sum of ERV, VT, and IRV
something useful with it, namely, ventilate and oxygenate and is called vital capacity (VC). The total volume within
the patient. This chapter will introduce readers to positive the lungs at maximum inspiration is the sum of all the
pressure ventilation (PPV) by discussing basic concepts and lung volumes, and we call it total lung capacity (TLC).
definitions in respiratory physiology and universal themes
in ventilator design. As we look at each of several classic
modes of ventilation, we will suggest typical applications, SCIENTIFIC UNDERPINNINGS OF PPV
guidelines for initial setup, and discuss the peculiarities of
each mode. Finally we will briefly summarize some of the Like all moving fluids, the gases that we breathe are
more recently developed approaches to mechanical ventila- pushed from a region of high pressure toward a region of
tion in difficult to ventilate or oxygenate patients. lower pressure. In the case of spontaneous breathing, the
diaphragm and other respiratory muscles work together
to expand the thorax and create negative intrathoracic
SPIROMETRY pressure relative to the outside atmosphere (note that
throughout this chapter and in most of physiology, pres-
Ventilation is simply mass movement of gas in and out sure will be measured relative to atmospheric pressure and
of the lungs, or breathing. Regardless of whether an indi- atmospheric pressure is considered to be zero). In the case
vidual is breathing spontaneously or with artificial PPV, of most artificial ventilation, we apply positive pressure
the volumes of gas moving in and out of the lungs can at the upper airway or within the trachea, and gas moves
be measured in a process called spirometry. When these toward the region of relatively lower pressure within the
measured volumes are added up, we refer to the resulting lungs. In both situations, expiration is mainly passive. It
sums as lung capacities. is driven by lung elasticity pulling the intrathoracic vol-
Figure 54-1 shows a graph of volume versus time for ume down and increasing intrathoracic pressure until, at
respiration, which begins as normal relaxed breathing the point of full exhalation during tidal breathing (FRC),
or tidal breathing. The volume moving in and out with the inward force of lung elasticity is equal in magnitude
each normal breath is called tidal volume (VT). At time and opposite in direction to the outward recoil of the
“a” on this graph, the person has inspired (breathed in) relaxed inspiratory muscles and other tissues of the chest
as much as possible and then at time “b” he has gone on wall. Additional active expiration may be accomplished
to expire (breathe out) as much as possible. Inspiratory by contraction of the internal intercostal muscles and the
reserve volume (IRV) and expiratory reserve volume muscles of the abdominal wall.
(ERV) are the maximum inspiratory and expiratory vol- Before we delve into the specific topic of mechani-
umes, respectively, that can be attained beyond tidal ven- cal PPV, it is worth mentioning that there are other ways
tilation. Residual volume (RV) is the volume remaining to provide artificial ventilation. First, there is the largely
379

380 PART XVI ■ CARE AFTER INTUBATION
6.0
IRV ⬵ 2.5L
IC ⬵ 3L
V 3.5 VC ⬵ 4.5L
V⫹ ⬵ 0.5L
(L) 3.0 TLC ⬵ 6L
ERV ⬵ 1.5L
1.5 FRC ⬵ 3L
RV ⬵ 1.5L
0
a b
t
F I GUR E 5 4 -1 Graphic representation of lung volumes and capacities in an average adult.
historical example of negative pressure mechanical and control. Unlike marketing pitches, the principles that
ventilation such as that provided by the iron lung. This govern the flow of gas in and out of human lungs are fairly
device surrounded the patient’s thorax while a seal simple and immutable. Fundamentally, any mechanical
excluded the neck and head. As the bellows, or, later, a ventilator is a machine that uses a pneumatic or electric
separate compressor, generated negative pressure in the power source to take over a patient’s work of breathing.
tube around the thorax, the chest wall transmitted it to the Naturally, this must occur in a carefully controlled fash-
lungs and air flowed into that low-pressure region, gener- ion in which some relevant variables related to respiration
ally by way of the natural airway. It served many patients can be measured and input into the ventilator control sys-
with neuromuscular respiratory failure for decades of their tem, which will process them and modify ventilator output
lives, but it is difficult to move about to say the least, and accordingly. If the reader can understand all the possible
even difficult to provide nursing care when the patient’s ways that someone might design a machine to interpret and
body must be encased by the ventilator, so it has now interact with these laws of fluids and respiratory mechan-
largely been replaced by PPV, even for patients with very ics, it should be easy to adapt to small modifications in
long-term ventilator dependence. the currently existing technology as they come about.
The other frequent exception to the model of Regarding the power source, most modern ventilators
mechanical PPV is that of manual PPV as provided by use some combination of electrical and pneumatic power.
anesthesia and critical care practitioners daily by means Since stored medical gas in hospitals is already pressur-
of a gas-filled bag attached to a one-way valve. Providing ized to approximately 50 psi, and gas stored in smaller
manual breaths via natural or artificial airway is a lifesav- tanks is at much higher pressure, it is efficient to use some
ing skill and can lead to a more intuitive understanding of the energy that is released in the process of expanding
of the principles of PPV. Nonetheless, even the most sea- stored gas to drive a bellows. Alternatively, some devices
soned anesthetist will fatigue at some point, so most of us simply use regulator valves that only decrease the pressure
will enjoy the luxury of being able to replace the work of down as far as the desired airway pressure mandates. On
our hands and forearms with a machine that is expressly the other hand, the power source for a transport ventila-
made to ventilate lungs. This brings us to the remainder tor or the backup power source for a stationary ventilator
of the chapter, which will explain principles and practice is typically an electric compressor. Similarly, the control
of mechanical PPV. system for a simple ventilator can be purely mechani-
Any reader who is not a respiratory therapist will cal and pneumatic as is the case for many of the simple
likely recall his or her first introduction to mechanical intermittent positive pressure breathing devices that are
ventilation as an alphabet soup of acronyms and confus- used to administer inhaled medications. Modern ventila-
ing definitions. Unfortunately, naming and availability tors, however, almost exclusively use electricity for their
of modes of ventilation is inconsistent between different control systems: alternating current circuits for the small
ventilator manufacturers. Furthermore, with the advent of motors and direct current circuits for the computer sys-
computer-controlled ventilators, the subtle variations in tems and sensors.
modes of ventilation have become potentially limitless. For The desired output of a mechanical ventilator is
this reason, it is worthwhile to pause and build a strong the- obviously ventilation. More specifically, appropriate
oretical framework for how we describe ventilator function ventilation must provide adequate minute ventilation.
DESIGN SERVICES OF

CHAPTER 54 ■ POSITIVE PRESSURE VENTILATION 381
F I GUR E 5 4 -2 Single alveolus model for respiratory mechanics.
Appropriate ventilation can minimize both dead space This relationship is dynamic because it involves a rate, and
ventilation (the amount of ventilation that does not it only applies when there is gas flow through the tube. If
participate in gas exchange because it is only in poorly there is no flow, then resistance is irrelevant, and the pres-
perfused parts of the lung or airway) and shunt (blood sure that we measure at the airway cannot be influenced
that cannot participate in gas exchange because it flows by it. Looking back at our balloon-on-a-straw however,
through parts of the pulmonary circulation that are not we can also easily understand that there is a second, static
well ventilated). For any patient there is an ideal balance force that opposes filling the balloon, and that is the elastic
point. We must provide large enough VT so that all per- properties of the expanding balloon itself. The pressure
fused portions of lung get ventilated and VT is much larger that the balloon will exert back on the gas within it is
than the wasted anatomic dead space ventilation, but we governed by its elastance and volume according to the fol-
must avoid applying so much pressure to the lungs that it lowing equations:
impedes pulmonary blood flow and increases physiologic
dead space. In addition, excessive positive airway pres- Elastance ⫽ Pressure / Volume
sure can be harmful to the tissue of the lungs and reduce
cardiac output, so the goals of ventilation must be bal- or, rearranged
anced against the desire to limit peak airway pressure. The
ideal rate of gas flow into or out of the lungs can also vary Pressure ⫽ Elastance ⫻ Volume
between individuals based on traits such as level of seda-
tion, respiratory drive, body habitus, or specific lung or If pressure at the mouth of the tube is set at a given amount
airway disease states. and ample inspiratory time is allowed, elastance will deter-
The three main variables of PPV, namely volume, pres- mine what volume enters the balloon. When the volume
sure, and flow, can be related to one another using a sim- is reached at which back pressure from the elastance of
plified model of respiratory mechanics. In this model, we the balloon equals airway pressure, flow will stop. Then
will imagine all of the airways, bronchi, and bronchioles if the positive airway pressure is reduced or removed, the
being represented as a single tube leading to a balloon that direction of the flow will be reversed until the pressure
represents all of the combined alveoli (Fig. 54-2). in the balloon is again equal to airway or ambient pres-
Using this single alveolus model, we can see that dur- sure. Note that we often discuss elasticity in terms of its
ing a positive pressure breath, the inspired gas would be inverse, compliance, which is simply change in volume
driven into the alveolus from a region of high pressure at over change in pressure.
the proximal airways toward a region of lower pressure in Combining the static and dynamic components of
the alveolus, but we can also imagine that this movement the work of breathing additively, we arrive at a simplified
would be opposed by the dynamic resistance to the flow of equation of motion for the respiratory system.
gas through the tube. The relationship between pressure,
flow, and resistance is described by the following equations. Total Pressure ⫽ Pressure from resistance
⫹ Pressure from elastance
Flow ⫽ Pressure / Resistance
or
or, rearranged
Total Pressure ⫽ Flow ⫻ Resistance
Pressure ⫽ Flow ⫻ Resistance ⫹ Elastance ⫻ Volume
DESIGN SERVICES OF

This equation of motion allows us to relate all of the key be modified by a human clinician, but they are essentially
variables of respiratory mechanics. Each of the variables constants from the perspective of the ventilator control
can be manipulated in one way or another. Resistance algorithm. In contrast, the flow, volume, and pressure
and elastance are generally characteristics of the patient, components of the equation of motion form the heart of
whereas pressure, flow, and volume are each variables that ventilator management.
that may be set by the ventilator.
Resistance to flow of an ideal fluid is described by
Poiseuille’s Law. PRINCIPLES OF VENTILATOR CONTROL
Resistance ⫽ (8 ⫻ viscosity ⫻ length) / (pi ⫻ radius4) As mentioned above, there are a plethora of specific modes
of mechanical ventilation, and we will only discuss a few
The natural airways are difficult or impossible to describe of the classics here. Before we proceed with this discus-
this way because they taper and branch and the flow in sion, though, it will be valuable to consider the ways a
most of the airways is turbulent, but Poiseuille’s Law is ventilator could be controlled in theory, because most of
still a worthwhile model to keep in mind. It forms the these approaches are indeed being used by one device or
theoretical basis for using a shorter, larger radius endotra- another.
cheal tube or giving bronchodilator medications to reduce First, what can a ventilator know? That is to say, what
the resistance to airflow, or even the practice of mixing variables are commonly input into a control algorithm?
helium into the inspired gases for patients with severe For a start, a ventilator must monitor the three essential
airway obstruction in the hope of reducing resistance by parameters that will determine the mass movement of gas
reducing fluid viscosity of the inspired gas itself. as discussed above: pressure, flow, and volume. Like so
Like resistance, elastance in a living human is more many other things, the exact location of these sensors (eg,
complex than our single alveolus model would suggest. inspiratory arm, expiratory arm, T-piece next to endotra-
Rather than a single balloon, the intrinsic lung elastance cheal tube itself) and subsequent way that the data is used
is a function of several hundred million alveoli and the varies between manufacturers. As a curiosity, it is also
tissue that forms them, as well as the airways themselves. notable that flow is the derivative of volume with respect to
The elastance of real lungs is not constant either. Rather, it time, and, inversely, volume is the integral (or area under
increases with increasing lung volume (Fig. 54-3). the curve) of flow over a period of time, so many ventila-
In healthy people with normal lung tissue, a more sig- tors measure one of these two variables and calculate the
nificant component of elastance is often related to extrin- other. If the ventilator does not have a bellows or piston,
sic sources. These include the pressure of an obese or most likely it is actually measuring flow and integrating
insufflated abdomen pressing up against the diaphragm, it to produce the values of volume that show up on its
variations in patient position such as Trendelenburg or settings or display screen. We will intentionally persever-
prone positioning, or forces from the tissues of the walls ate on pressure, flow, and volume, but perhaps the most
of the thorax including active movements of the respi- fundamental variable that the ventilator keeps track of is
ratory muscles, which may aid or oppose the ventilator. time. Almost any other variable for which an electronic
These factors are all important to consider, and they can sensor has been invented is fair game for the ventilator
to monitor and respond to, and there are a few notable
examples. Many modern anesthesia ventilators integrate
the concentrations of several inspired and expired gases
into their displays, and even many intensive care ven-
tilators measure and display or trigger alarms based on
inspired O2 and expired CO2 levels. It is also possible to
use pressure sensors outside of the ventilator circuit or
even electrodes on the chest that measure impedance to
estimate chest volume. Indeed, both of these techniques
P
are used clinically to trigger the inspiratory phase in some
infant ventilators. Of course, ventilators must also be able
to act on human operator inputs and most of their func-
tions can be triggered manually by a clinician. As any of
these variables are measured and input into the ventilator
control system, they can be used for different purposes,
V
and we will categorize them further based on what the
control algorithm does with them.
F I GUR E 5 4 -3 Pressure versus volume for inspiration (slope A control variable is simply the parameter that the
of a tangent is equal to compliance). ventilator controls during inspiration. Its magnitude could
DESIGN SERVICES OF

be constant, but just as often it varies over the inspira- tive pressure), flow (the ventilator gives a breath when
tory time as is demonstrated by the many waveforms in the patient creates a small inspiratory flow), and simply a
Fig. 54-4. Note, for instance, that the first pressure con- manual breath in which an operator triggers the inspira-
trol waveform applies constant pressure, but the second tory phase by pushing a button on the ventilator control
uses an ascending ramp waveform for pressure. Both of panel. The inspiratory phase is ended by a cycle variable.
these examples are still using pressure as the control vari- Common examples include time (continue inspiration for
able though. In mathematical terms, the control variable a preset time period and then cycle to expiration), pres-
is the independent variable in the equation of motion, and sure (terminate the inspiratory phase when a high pres-
at any given time, the other two ventilator-specific vari- sure is reached), volume (permit expiration as soon as the
ables depend on the interplay of the control variable with breath reaches a set volume), or flow (cycle from inspi-
the patient-specific properties of elastance and resistance. ration to expiration when the inward flow of gas drops
For example, if we set a particular pressure waveform as below a certain rate). Finally, if one of the variables related
the control variable, then VT and flow rates will result to respiration is limited at a certain level during the inspi-
based on the resistance and elastance of the system. They ratory phase it is called a limit variable. This can be a con-
are directly related to each other, and if the pressure is fusing concept, but it may help to consider the real world
increased, higher volume and flow will result, whereas if example of how we could keep a ventilator from applying
the pressure is set lower, there will be a decrease in the too much positive airway pressure to a patient during a
volume and flow delivered. On the other hand, if a mode volume controlled breath. Anyone who has spent a few
of ventilation that specifies volume or flow for the control hours in an intensive care unit (ICU) will have some frame
variable is chosen, then we cannot have direct control over of reference for this because most of the ventilator alarms
the pressure that is generated to reach that target, but we that we hear echoing down the hallways are the result of
still know that the variables will be directly proportional a high-pressure alarm going off. The way that a ventilator
to one another. As noted previously, volume and flow are is set to respond to that high-pressure event illustrates the
closely related, with flow being the derivative of volume difference between a limit variable and a cycle variable.
with respect to time, so for clinical purposes when we con- If we set an upper level of pressure that we will tolerate
trol one of these two variables over a set period of time, we as a true limit variable, then when that level is reached
are, in essence, controlling the other. during an attempt at inspiration, the inspiratory phase
With regard to time, our simplified equation of will continue—but at the cost of a reduced flow, longer
motion explains some important relationships, but it does inspiratory time, or failure to reach the targeted volume.
not tell us much about how they change over the time In contrast, if a set pressure “limit” is exceeded and the
of a respiratory cycle. First, recall that elastance increases ventilator responds to the event by terminating the inspi-
with increased lung volume, so during inspiration, elas- ration, then this high-pressure value is not really being
tance increases with time also. In contrast, resistance is used as a limit variable by the ventilator, rather it is a cycle
usually higher at lower lung volumes, but the magnitude variable. In fact, the latter is the more typical action that a
of that change is smaller over a typical respiratory cycle, so ventilator takes when the high-pressure “limit” is reached.
we can usually ignore it. The remaining relationships will Note that the first situation is an example of a dual control
always be consistent with the equation of motion, but we mode because the inspiratory phase is initiated with vol-
can set various waveforms for the control variable. Some ume being the control variable, but after a high-pressure
common control waveforms and typical resulting wave- limit is reached, it switches to a pressure controlled breath
forms of the dependent variables are shown in Fig. 54-4. for the remainder of that inspiratory cycle (Fig. 54-5).
At this point we have described in theoretical terms
most of the fundamental inputs and outputs that let a ven-
PHASE VARIABLES tilator “know” how to deliver a positive pressure breath to
a patient, but as was described above, modern ventilators
A phase variable is a variable that directs a ventilator to are equipped with fairly sophisticated computers and can
initiate, sustain, or terminate inspiration, or to maintain take on many tasks beyond controlling a single inspira-
some type of baseline characteristic during the time des- tory cycle. Between breaths and over longer periods of
ignated for passive expiration. More specifically, there are time, most ventilators are busy processing larger condi-
four names for these subtypes of phase variables. A base- tional statements to determine that each breath is cycled
line variable is a variable that is controlled during expira- based on the correct set of control and phase variables.
tion, and the most common example would be positive end Ventilators can even use feedback from prior breaths to
expiratory pressure (PEEP). The variable that causes the change the way future breaths will be delivered. At the
ventilator to initiate inspiration is called a trigger variable. extreme end, a few ventilators can use information about
Some common trigger variables are time (the ventilator past respiratory rate and VT to provide a minimum level of
gives a breath at a set frequency), pressure (the ventilator assistance to the patient and automatically wean through
gives a breath when the patient generates a small nega- decreasing levels of ventilatory support. More typically,
DESIGN SERVICES OF

F I GURE 5 4 -4 Common pressure, Pressure control

volume, and flow control waveforms.
·
P V V
t t t
·
P V V
t t t
Volume control
·
V P V
t t t
·
V P V
t t t
Flow control
·
V V P
t t t
·
V V P
t t t
DESIGN SERVICES OF

High pressure as High pressure as FIG U RE 54-5 Flow, pressure,

limit variable cycle variable and volume versus time for a
high-pressure alarm acting as
limit variable (left) compared with
high-pressure alarm acting as cycle
Inspiration ends variable (right).
Inspiration
· · and expiration begins
continues
V V
Flow
control
t t
Pressure
control
P P
t t
V V
t t
most of our key alarms rely on integration of spirometric output variables in the inspiratory phase compared with
or other data over successive breaths, and the ventilator the expiratory phase. In contrast, during the supported
will sound an alarm and may switch to a more support- breath, the ventilator provides higher airway pressures
ive mode of ventilation or to a backup system if variables during an inspiratory phase, but the breath is triggered
such as expiratory time, minute ventilation, inspired oxy- and cycled based on changes that the patient evokes. An
gen concentration, input power, pressure, or others fall assisted breath is triggered by some action by the patient,
outside of a predetermined range. but after that, all of the limit and cycle variables are deter-
The last necessary component of ventilator mode clas- mined by the ventilator independent of any input from the
sification is often called “breath type” and refers to the patient. Finally, a mandatory breath is one in which the
source of the phase variables—that is, does the patient or trigger, limit, and cycle variables are all based on the ven-
ventilator produce the changes that will trigger or cycle tilator’s work, without any input from the patient. These
the breath? There are four types of breaths in this respect. breath types are a key way that we classify modes of ven-
First, if a breath is triggered and cycled based on the tilation. A brief but useful classification of any mode of
actions of the patient, it is a spontaneous breath. Some ventilation can be made by identifying the predominant
authors make a further distinction, subdividing this cate- breath type that it offers (often stipulating whether this
gory into the completely spontaneous breath and the sup- breath type is continuous or intermittent) and identify-
ported breath. In this scheme, a truly spontaneous breath ing the control variable. Mentioning any peculiar phase or
is one in which the ventilator does not change any of its conditional variables provides the ultimate level of detail.
DESIGN SERVICES OF

We are finally ready to look at common specific modes of sedated or paralyzed, or for any other reason the patient
ventilation. does not initiate any inspiration between the mandatory
breaths, then the ventilator output will be identical to
CMV, with only mandatory breaths occurring. Likewise,
MODES OF VENTILATION if the threshold for the patient to trigger an assisted breath
is set very high (meaning the patient must generate an
We will now look at several essential modes of positive unattainably large negative pressure or high inward flow
pressure mechanical ventilation and describe them in to trigger a breath) then the mode really will function just
terms of breath type, control variable, and phase variables. like CMV in every practical way. In contrast, if the man-
datory rate is set at zero, then every breath will have to
Continuous Mandatory Ventilation be triggered by the patient. Some ventilators separate this
Continuous mandatory ventilation (CMV) is a mode of assist-only mode as a separate menu option called Assisted
ventilation in which every breath is mandatory, that is, Mechanical Ventilation (AMV), or simply Pressure Assist
machine triggered and machine cycled. In its broadest or Volume Assist, depending on the control variable.
form it can be either volume controlled or pressure con-
trolled, and, for clarity, it should be referred to as VC-CMV Intermittent Mandatory Ventilation
or PC-CMV, respectively (although we know that, to be Although there are inconsistencies between manufactur-
more precise, modes called volume control are often per- ers, in general, intermittent mandatory ventilation (IMV)
forming flow control over a set time period). Many clini- is a mode of ventilation in which fully mandatory breaths
cians and ventilator menus refer to these as simply VC or are given at a set rate (time triggered with machine-based
PC using the somewhat confusing convention of calling a limits and cycle variables), but between those mandatory
mandatory breath a “controlled breath” (we will not use breaths the patient is permitted to take either fully spon-
this terminology further here). The trigger variable will taneous (similar to continuous positive airway pressure
usually be time, but the limit variable can be pressure, vol- (CPAP) as described below) or supported breaths (similar
ume, or flow, and the cycle variable could be pressure, vol- to pressure support ventilation (PSV) as described below).
ume, flow, or time. Because it is a fully mandatory mode
with no useful or synchronized way to respond to patient Synchronized Intermittent
interaction, CMV is best suited to deeply sedated or para- Mandatory Ventilation
lyzed patients. Like IMV, synchronized intermittent mandatory
ventilation (SIMV) is a mixture of mandatory and sponta-
Assist/Control neous or supported breaths but with some added flexibil-
Assist/control (A/C) is a mode of ventilation in which man- ity. Although conventional IMV delivers the mandatory
datory breaths must occur at a set minimum frequency, so breaths based only on a time trigger, SIMV uses a more
its fully mandatory breaths are time-triggered. Above that complex algorithm to synchronize the mandatory breaths
minimum rate, however, it will also sense patient effort with the patient’s own respiratory effort. In effect, there is
(either in the form of a small negative pressure or a small a window of time based on the set mandatory rate. If the
inward flow) to trigger a breath. After the patient triggers patient makes an inspiratory effort during that window, he
the breath, the limit and cycle variables will be reliant on will receive an assisted breath (patient trigger but volume,
the ventilator’s actions and generally are the same as those flow, or time cycled). If no inspiratory effort occurs, at the
of the mandatory breaths. By definition then, these extra end of the window, the patient will receive a mandatory
breaths are assisted. Aside from the different source of breath. As with IMV, any breath between these manda-
the trigger for assisted and controlled breaths, the con- tory or assisted breaths may be spontaneous or supported.
trol, limit, cycle, and baseline variables for the assisted In reality, many modern ventilators no longer offer even
and controlled breaths are usually identical. Just as we basic IMV; instead they make use of only its synchronized
saw with the term “CMV,” calling the mode “A/C” com- form.
municates the breath types that are available, but to be
clear, we would then need to further stipulate whether it Pressure Support Ventilation
is pressure control A/C or volume control A/C. In practi- PSV relies on patient effort to trigger every breath. After
cal terms, this could be inferred from the ventilator orders that, the patient receives support in the form of higher-
because in addition to writing A/C, we will either order a than-baseline positive airway pressure. The cycle vari-
desired pressure or a desired volume. able is often flow, so if the inspiratory flow drops below
Within the boundaries of the definition above, it is a certain rate, this signals that the patient is unwilling
interesting to consider different ways that A/C can be or unable to inspire any more, and the airway pressure
manipulated to be more like or unlike CMV. For instance, is decreased back to its baseline level so the patient can
if the set minute ventilation is higher than necessary for fully expire. Alternately, the cycle variable can be pres-
the patient’s metabolic demands, the patient is thoroughly sure, in which case an elevation in pressure beyond
DESIGN SERVICES OF

the inspiratory pressure would signal that the patient has APRV certainly provides a great deal of flexibility in
stopped inspiring or is trying to actively expire. Baseline the way that it is applied, but it is not without its hazards.
expiratory pressure can be positive (PEEP) or zero. The principal concern with this mode of ventilation is the
Note that in PSV, if the patient does not initiate a relatively high mean intrathoracic pressure that is gener-
breath, there is no backup mandatory breath built into the ated. This could apply just as well to any other mode that
mode. Thus, we rely on an apnea alarm to alert us to this incorporates high PEEP or high mean airway pressure.
life-threatening state, and most ventilators will automati- We have not yet discussed the effects of PPV on
cally switch to a mandatory mode after a prolonged period hemodynamics in much detail, but they can be significant.
of apnea. Clearly, close monitoring and clinician inter- As positive pressure is applied to all the contents of the
vention are necessary with any mechanical ventilation, chest, the initial effect in some patients may be augmen-
especially when adjustments and changes in the mode of tation of cardiac output and mean arterial pressure for a
ventilation are made. few seconds mainly due to a brief increase in the pulmo-
nary venous blood flow to the left atrium and a subsequent
Continuous Positive Airway Pressure increase in preload to the left ventricle. However, over a
In true CPAP ventilation, all breaths are spontaneous. longer period of time, the transmitted positive intratho-
Regardless of whether the patient is inspiring or expiring, racic pressures of PPV will have a much more relevant
the ventilator maintains the same level of positive airway effect of decreasing cardiac output by impeding flow
pressure. The ventilator still monitors flow, volume, and through the vena cava and pulmonary circulation.1 There
pressure, and displays available spirometric data, but there may also be negative effects from the external compres-
are no phase variables that are likely to influence ventila- sion of the aorta, but since similar pressures are applied
tor output. to both the left ventricle and the aorta at the same time,
this is probably a more subtle factor in reducing cardiac
Airway Pressure Release Ventilation output. Naturally, the clinical impact of the decrease in
This final mode goes by several names and is probably the preload in the presence of PPV depends on the magnitude
most complex to classify because within the same rules of the maximum, minimum, and mean intrathoracic pres-
for ventilator operation it can be adjusted to fill several sure. This effect can be minimized by ensuring adequate
clinical roles. One of its names, Bilevel CPAP, describes intravascular volume and normal baseline cardiac func-
the mode well when a patient is making an inspiratory tion. The adverse effect from PPV itself must always be
effort, but when the patient makes no such attempt at considered in the differential diagnosis for hypotension in
inspiration, airway pressure release ventilation (APRV) the mechanically ventilated patient.
functions much like PCV. As is customarily used, a period The second main danger of APRV (or any mode of
of high constant airway pressure is cycled alternately with ventilation that uses more inspiratory than expiratory
a period of low fixed airway pressure, based only on time time) lies in the phenomenon of intrinsic or auto-PEEP.
as the trigger and cycle variables. Furthermore, there will This is the process of “stacking” lung volumes from one
be no limit or cycle variables that the patient is likely to breath to the next because of inadequate expiratory time.
activate. The overall period of the respiratory cycle tends It is most common in patients with obstructive lung dis-
to be set relatively long, and there is usually an inverse ease. This process may be first appreciated by noting that
inspiratory to expiratory (I:E) time ratio in which inspira- expiratory flow does not return to zero at end expira-
tory time (often called high-pressure time) is significantly tion. More formally, we can also look for intrinsic PEEP
longer than expiratory time (often called low-pressure by performing an expiratory hold maneuver in a sedated
time). Mass movement of respiratory gasses will occur or paralyzed patient. In this test, at the end of a typical
with the switch from high to low pressure and back again, expiratory cycle, the ventilator stops flow. If there is no
but the patient can also take spontaneous breaths at any intrinsic PEEP, then the airway pressure will remain con-
time, without causing the ventilator to cycle to a different stant during the expiratory hold, but if there is significant
airway pressure, just as in CPAP. airway obstruction and intrinsic PEEP, then the alveolar
As another form of a pressure control mode with pressure will continue to equilibrate with the pressure in
inverse I:E, APRV has found a small niche providing the ventilator tubing, and the measured airway pressure
improved oxygenation and reducing atelectasis at accept- will increase during the hold maneuver.
able peak pressures for difficult to ventilate or oxygenate It should be noted that this test will be unreliable and
patients (Fig. 54-6). At the other end of the spectrum, it uncomfortable for a patient who is making respiratory
can guarantee a certain amount of gas movement based on effort. Because it is caused by poor emptying of the alveoli
the switch between high and low pressure, while permit- and produces alveolar pressures that are higher than the
ting spontaneous ventilation at any part of the ventilator measured expiratory airway pressure, this phenomenon
cycle. Therefore, it can easily be adjusted to provide CPAP of intrinsic PEEP can lead to high intrathoracic pressure
support with a sigh, release, or low rate mandatory PSV that is not necessarily reflected in the measured expiratory
breaths built in. pressure on the ventilator display, so the clinician must be
DESIGN SERVICES OF

F I GUR E 5 4 -6 Pressure, No patient effort Patient effort

volume, and flow versus
time for APRV with and High
without patient effort pressure
(right and left sides,
respectively).
P
Low
pressure
High Low
time time
t
·
V
vigilant to detect it. At its extreme, high intrinsic PEEP can Scenario 1: An Obese Woman
cause pulseless electrical activity and cardiac arrest by an with a Surgical Complication
enormous reduction in venous return to the heart, but the In the first scenario, our patient is a 56-year-old woman
short-term solution is as simple as disconnecting the endo- with hypertension and diabetes, but no lung disease, who
tracheal tube from the ventilator to allow full expiration and came to our hospital for an elective laparoscopic gastric
restore lifesaving preload and cardiac function (Fig. 54-7). bypass procedure. She is 168 cm tall (66⬙) and weighs
130 kg (286 lb). After intravenous induction of general
anesthesia, an endotracheal tube is inserted without inci-
CLINICAL APPLICATION dent, and we begin to ventilate the patient. For the proce-
dure, she is under general anesthesia. To meet the needs
Now that we have constructed a catalog of the most com- of the surgeon and for improving our ease of ventilation,
monly used modes of ventilation, we will explore how they we will also keep her paralyzed with a nondepolarizing
can be used practically by considering two clinical scenarios. neuromuscular blocking drug for most of the case.
DESIGN SERVICES OF

FIG U RE 54-7 Pressure, volume, and flow

versus time during expiratory hold maneuver
for patient with (left) and without (right)
intrinsic PEEP.
P P
Intrinisic
PEEP
t t
V V
t t
· ·
V V
t t
Question: How will we set up the anesthesia ven- we begin ventilating the patient, we also notice that the
tilator? Because the patient is paralyzed and under gen- partial pressure of expired carbon dioxide (end-tidal CO2
eral anesthesia, we will want a mode of ventilation that or ETCO2) is only 28 mm Hg, while we would expect it to
relies on mandatory breaths. As we do not know anything be around 35 in a normal patient (allowing for approxi-
about her initial lung compliance, we choose a VC-CMV mately 5 mm Hg gradient between arterial and alveolar
mode that is just called VC on the menu of our anesthesia CO2 concentration). Most likely we have caused a respira-
ventilator. Our routine is to initiate ventilation with VT of tory alkalosis by hyperventilating the patient, so we titrate
about 8 mL per kg of body weight (8 mL/kg ⫻ 130 kg ⫽ the rate downward and eventually find that a respiratory
1040 mL), but since this patient is obese, we will use rate of 10 breaths per minute is just right to keep the
ideal body weight in the calculation (8 mL/kg ⫻ 62 kg ⫽ ETCO2 around 35 where we want it. Alternately, we could
496 mL) and start ventilation with VT of 500 mL and a have decreased the VT. Everything is running smoothly as
respiratory rate of 12 breaths per minute. This yields a the patient is prepped and draped, but soon we meet our
minute ventilation of about 6 L which seems reasonable. first challenge as the surgeon makes a small incision and
By convention, we will start the ventilation immediately begins inserting her laparoscopic ports and insufflating
after induction of anesthesia with a fraction of inspired the patient’s abdomen. Because this patient is obese and
oxygen (FIO2) near 100 % (pure oxygen). has such a thick abdominal wall, the surgeon requires an
As it turns out, the patient’s metabolic needs are even intra-abdominal pressure of at least 15 cm H2O to form the
less under general anesthesia than we had predicted. We space in which she will work. This same pressure is trans-
have decreased the FIO2 to around 50%, and the pulse mitted up against the diaphragm, and now at our settings
oximeter is still hovering near 100%. A few minutes after of Vt ⫽ 500 on the volume control mode, we find that
DESIGN SERVICES OF

the peak airway pressure has risen from about 25 cm H2O resistance. This distinction is also relevant because we
to well over 40. Because we are concerned that this high think that the plateau pressure is more closely linked to
level of positive airway pressure can impede venous return the development of lung injury from high pressure or
to the heart, worsen mismatch of ventilated and perfused stretch injury than peak pressure is.
zones of the lungs, and perhaps even cause direct injury Question: How can we keep from exceeding a
to the lungs, we would like to find a ventilation strategy reasonable airway pressure while still ventilating the
that can provide the same or better ventilation at lower patient well? We have decided that we would like the
airway pressures. peak airway pressure to be less than 30 cm H2O for this
In this case, we feel confident that the timing and patient, so we try a pressure control version of CMV. We
magnitude of this increased airway pressure is related to also want to minimize atelectasis from the high intra-
insufflation of the abdomen rather than any intrinsic pul- abdominal pressure, so we will add a small amount of
monary disease, so we do not plan to investigate it further. PEEP, such as 5 cm H2O. Now we set the inspiratory
If we were unsure about the source of the increased air- pressure at 25 cm H2O and see what volume results.
way pressure though, we could gather more information This change alone ends up giving the patient 450 mL
by performing an inspiratory hold maneuver. Recall that VT at much lower pressure. Part of this benefit is that,
in the equation of motion for the respiratory system, there like many ventilators, the one attached to our anesthesia
is a static component from lung elastance and a dynamic machine uses a different waveform for PCV compared
component in the form of airway resistance. During inspi- with VCV. The square pressure wave and descending flow
ration, we observe an increase in airway pressure that wave of PCV means that the peak pressure is the same
depends on both of these variables. In the inspiratory hold as the mean, and we get the maximum volume out of
however, we stop flow at the end of a typical inspiratory that peak by holding it throughout the entire inspiration,
cycle and look at the airway pressure when there is no whereas our VCV mode had been using a square flow
flow. This value is called plateau pressure. Without any wave that results in an upward slanted pressure wave
flow, the airway pressure is only due to the elastance of with a higher peak for the same mean value. We again
the system (P ⫽ EV), so if plateau pressure is very close titrate the rate to attain an end-tidal CO2 around 35. At a
to peak pressure, then we know that resistance must be rate of 14, we find that we are adequately ventilating the
low, and most of the observed airway pressure during patient without exceeding our goal high-pressure limit
inspiration is due to elastance. This would presumably be (Fig. 54-8).
the case with our patient with decreased lung compliance From this point on, we find that the ventilatory needs
secondary to increased intra-abdominal pressure. On the of the patient are pretty stable. Unfortunately, about
other hand, if the plateau pressure is much lower than the 2 hours into the case, we learn suddenly that a compli-
peak pressure, then resistance to airflow (ie, the part of cation has occurred. The surgeon has inadvertently dam-
the total airway pressure that we have removed in this aged some vascular structure—perhaps it is the splenic
maneuver) is probably contributing most of the increase in artery—and brisk bleeding ensues. Within a few minutes,
peak airway pressure. Bronchospasm would be an exam- she has converted to an open laparotomy, but not before
ple of increased peak airway pressure due to increased the patient has lost a large quantity of blood. The patient
F I GUR E 5 4 -8 Comparison of square

pressure wave and square flow wave.
·
P V V
Peak ⫽
Mean
t t t
·
V V P
Peak
Mean
t t t
DESIGN SERVICES OF

becomes hypotensive and eventually loses about 2.5 L of than a day, we can probably jump straight to a trial of
blood. Furthermore, she ends up requiring transfusion of low-level pressure support or even CPAP. We quickly
several units of blood products, 1 L of colloid, and, by see that she does fine on PSV with FIO2 of 50%, inspira-
the end of the case, about 8 L of crystalloid fluids. The tory pressure of 10 cm H2O, and PEEP of 5 cm H2O. We
bleeding is stopped and the case completed by way of the feel confident that she will be successfully extubated at
laparotomy, but as the surgeon begins to close, the patient this point but proceed to a trial of CPAP at 5 cm H2O.
continues to require at least 75% FIO2 to keep pulse oxim- With this minimal assistance, she is able to take 350 to
etry above 92%, and because we appreciate diffuse rales 450 mL VT at a rate of 18 breaths per minute for almost
on auscultation of the lungs, we suspect she has acute an hour.
pulmonary edema. Hopefully, this is just from aggressive Question: How can we predict which patients will
volume resuscitation in the face of some diastolic dysfunc- tolerate extubation? There are several indices that have
tion from her longstanding hypertension, rather than any some predictive value in determining which patients will
new problem like myocardial infarction. Postoperative succeed after extubation and which will require reintuba-
chest X-ray and electrocardiogram (EKG) in the postan- tion and continuation of mechanical ventilation. In gen-
esthesia care unit (PACU) seem to support this diagnosis, eral, we would like to see that the patient is able to take
but regardless of the cause, the patient is not tolerating large breaths, is comfortable breathing slowly, and pro-
low enough FIO2 to extubate. She will stay in the ICU for duces adequate minute ventilation. Sedating medications
diuresis and ongoing mechanical ventilation. She is lightly should be stopped before the extubation is performed. One
sedated overnight, but is making respiratory efforts, so of the best-validated indices that encompasses several of
neither of the modes of ventilation that we have used so these variables is the rapid-shallow breathing index. It is
far seems appropriate. defined as respiratory rate divided by VT in liters (RR/VT).
Question: What mode of ventilation is appropriate When it is above 105, it predicts failure at extubation, and
for a lightly sedated patient in the ICU? We have sev- when it is less than 105 it predicts success after extuba-
eral options here, but because difficulty in weaning FIO2 tion.2 For our patient, this index is 18/0.4 L or 45, so we
is going to keep the patient mechanically ventilated for the feel fairly confident that if we extubate her she will flour-
time being, we will choose volume control A/C. We try VT ish. We do, and she does.
of 500 mL, mandatory rate of 10 breaths per minute, and
continue PEEP of 5 cm H2O and the same 80% FIO2 that Scenario 2: An Elderly Veteran
we were using in the PACU. with Pneumonia
An initial arterial blood gas (ABG) shortly after arrival Our next patient is a 69-year-old man who is a two-
at the ICU confirms good correlation between the labo- pack-per-day smoker but has no other past medical his-
ratory measurements and our pulse oximeter’s estimate tory (though he admits he has not seen a doctor in many
of oxyhemoglobin saturation, so we will titrate the FIO2 years). He is 180 cm tall (71⬙) and weighs 75 kg (165 lb).
downward as tolerated based on bedside pulse oximetry. We meet him when he presents to the emergency depart-
The ABG also shows that the patient has a mild respira- ment of the local VA Hospital. He says that he has been
tory acidosis with arterial partial pressure of carbon diox- feeling ill for about 3 days, with a progressive cough,
ide (PaCO2) of 48 mm Hg, but since the time that the shortness of breath, and fever. His wife notes that he is
sample was drawn, we notice that she has begun triggering having chills for the past 2 days. He did not want to seek
a few extra assisted breaths every minute, in addition to care, but he can no longer even walk to the bathroom in
the mandatory rate of 10, and in this way she is increasing his house without becoming severely dyspneic and light-
minute ventilation to meet her own needs. headed. At this point, his respiratory rate is 36 breaths per
By the time we see the patient the next morning, minute at rest, and he is visibly straining and using acces-
she has diuresed several liters of urine with correspond- sory muscles of respiration. Auscultation of the lung fields
ing improvement in her chest X-ray and lung examina- reveals both wheezing and diffuse rhonchi. Pulse oximetry
tion, and she is tolerating 40% FIO2. She is arousable and does not seem to be working well, presumably because
appropriate in her interaction and occasionally initiates an of his poor peripheral perfusion (his hands are cold and
assisted breath. Cardiac enzymes and EKG have continued a little bluish), but it is yielding numbers that are gener-
to be normal, and she is normotensive on maintenance flu- ally between 75% and 85%. He continues to have apparent
ids and without any pressor medications. It seems that she respiratory distress despite the 100% non-rebreather oxy-
may be able to tolerate extubation, but we would like to gen mask that we started on his arrival at the emergency
see how well she takes over the work of breathing before department, so after a very brief discussion with him and
we actually remove the endotracheal tube. his wife, we make a clinical decision to secure the airway
Question: What mode of ventilation can we use to and mechanically ventilate him in the hope that this will
predict whether the patient will tolerate extubation? provide adequate oxygenation. Intubation proceeds with-
Again, we have several options here, but for this patient out incident, and we manually ventilate the patient while
who has been reliant on mechanical ventilation for less waiting for a ventilator to be set up at the bedside. In the
DESIGN SERVICES OF

meantime, his ABG results come back showing the follow- Question: How do we ventilate differently for the
ing values. patient with ARDS? The cornerstone of ventilation for
patients with ARDS and ALI is with low VT. Traditional VT
pH 7.50 with mechanical ventilation had been 10 to 15 mL per kg
PaO2 62 mm Hg IBW, but in 2000, the results of the ARDS Network study
of low VT established that by limiting VT to around 6 mL
O2 saturation 93%
per kg IBW rather than the usual 12 mL per kg, mortal-
PaCO2 42 mm Hg ity in patients with ARDS could be reduced from around
HCO3 32 mmol/L 40% to around 30%.4 This was despite generally increased
FIO2 100% hypoxia and hypercapnea in the reduced VT group. Part
of the basis of this benefit is thought to be due to limiting
We interpret this ABG as severe relative hypoxemia (given pressure injury (barotrauma) or stretch injury, so we also
the pure oxygen he is breathing) with metabolic alkalo- monitor plateau pressure regularly in patients with ARDS
sis and perhaps a small amount of respiratory compensa- and strive to keep it below 30 cm H2O. For our example
tion, but given this patient’s clinical history as a lifelong patient, we have already selected a VT of 8 mL per kg IBW,
smoker who now has a prototypical history of pneumonia, which is reasonable, but we find that he is still having peak
we speculate that these values are most consistent with airway pressures well over our goal of 30 cm H2O. When
acute hypoxemic respiratory failure from his pneumonia we perform an inspiratory pause, we find that the plateau
and reversal of his chronic respiratory acidosis due to a pressure is also 32, so the high peak pressures are due in
hypoxemic respiratory drive but persistence of the com- large part to a problem with lung compliance rather than
pensatory metabolic alkalosis. The ventilator arrives and an obstructive process. We further decrease our VT, and
we initiate A/C with 100% FIO2, VT of 600 mL (8 mL/kg we find that at a VT of 450 mL we can keep plateau pres-
⫻ 75 kg), respiratory rate of 20, and PEEP of 5 cm H2O. sure well below 30.
Chest X-ray is performed to examine the lung fields and Although we are using evidence-based ventilatory
check endotracheal tube placement, and it shows diffuse strategies in our patient with ARDS, he does not do well.
bilateral pulmonary infiltrates. EKG shows some nonspe- We have initiated broad antibiotic therapy for his com-
cific T wave inversion but a sinus rhythm, cardiac auscul- munity-acquired pneumonia and adequately resuscitated
tation reveals only distant heart sounds without any other him, but he continues to have refractory hypoxemia and
abnormality, and there is no other indication of cardiac we are unable to wean him from 100% inspired oxygen.
disease. Because the patient is hypotensive, tachycardic, Repeat ABG on the second day of his hospitalization
tachypneic, and febrile, he clearly meets criteria for sep- shows that pH is more normal as his bicarbonate level has
sis syndrome and we place a central venous catheter to decreased from the previous day, but the severe hypox-
monitor his central venous pressure. This turns out to be emia persists with PaO2 of 58% on 100% FIO2. The per-
low at 2 cm H2O, so again, we have no indication that the sistence of hypoxemia on 100% FIO2 for over an hour is
patient has heart failure or volume overload causing his sometimes used to define refractory hypoxemia.5
pulmonary infiltrate. Question: How can we treat refractory hypoxemia?
Question: Does this patient have acute lung injury Perhaps the better question is should we treat refractory
(ALI) or acute respiratory distress syndrome (ARDS)? hypoxemia? Our answer is probably, yes. Despite the very
ARDS is characterized by acute onset of severe respiratory high mortality in cases like this example, it is plausible
distress; bilateral infiltrates on frontal chest radiograph; that quality of life could be improved and permanent
no quantitative or clinical signs of left heart failure; and organ damage reduced in survivors by minimizing time
severe hypoxemia. The hypoxemia is further quantified by spent with severe hypoxemia. There are a few simple strat-
calculating the ratio of arterial partial pressure of oxygen egies such as conservative fluid management and higher
or PaO2 (expressed in millimeters of mercury) to FIO2 (as PEEP and many more creative techniques including high-
a decimal, that is, 100% ⫽ 1 or 21% ⫽ 0.21). If it is less frequency oscillatory or percussive ventilation, APRV or
than 300, this defines ALI, and if it is less than 200, this the related mode of pressure control inverse ratio ventila-
defines ARDS.3 Our patient certainly meets all the criteria tion (PC-IRV), addition of inhaled nitrous oxide or other
above, and when we calculate the ratio of PaO2 to FIO2 vasodilators to the inspired gas mixture, prone position-
we get 62 (62/1.0), so the patient has ARDS. It is interesting, use of neuromuscular blocking agents, and perhaps
ing to note that aside from excluding volume overload or corticosteroid administration to name just a few that
congestive heart failure, the precise etiology of the ARDS offer some improvement in oxygenation. Sometimes this
is not really considered in the definition. In our case, the improvement is brief, but for other interventions, there
patient probably has a primary pulmonary process, but if is reasonable evidence that it can persist for days after
his ARDS were the result of an extrapulmonary infection, the intervention is completed. Unfortunately, regardless
pancreatitis, or any number of other causes, we would of whether oxygenation is improved or not, we know of
still classify and treat his disease similarly. no ventilatory or nonventilatory technique for improving
DESIGN SERVICES OF

refractory hypoxemia that has been well established as also a brief time to search for underlying problems that can be
improving survival. For this reason, it is worth trying the corrected. The techniques described above should provide
techniques that are safe and available, but it becomes hard a generous selection of tools that clinicians can adapt to
to defend them as they become more risky and expensive. support a patient in the meantime.
We try to achieve better oxygenation using neuro-
muscular blockade and PC-IRV for 2 days. Oxygenation
does improve and we wean to 70% FIO2, but by day 5, the REFERENCES
patient is back to the same high requirement for inspired
oxygen and full mandatory ventilation despite the fact 1. Lumb AB. Respiratory support and artificial ventilation. In
that we are now well on the way toward fully treating Lumb AB, ed. Nunn’s Applied Respiratory Physiology. 6th ed.
his sepsis and pneumonia. He has stable hemodynam- Philadelphia, PA: Elsevier Limited; 2005:435–437.
ics and improvement of his fever and leukocytosis. After 2. Yang KL, Tobin MJ. A prospective study of indexes pre-
2 weeks in the ICU and a tracheostomy, we still do not see dicting the outcome of trials of weaning from mechanical
ventilation. N Engl J Med. 1991;324(21):1445–1450.
improvement in respiratory function. The patient becomes
3. Bernard GR, Artigas A, Brigham KL, et al. Report of the
tachypneic and his oxygen saturation drops anytime his American-European consensus conference on ARDS: defi-
sedation is reduced, he is not very interactive with staff or nitions, mechanisms, relevant outcomes and clinical trial
family even when he is not sedated, withdrawing to pain coordination. Intens Care Med. 1994;20(3):225–232.
but not communicating otherwise. We cannot offer a very 4. The Acute Respiratory Distress Syndrome Network.
encouraging prognosis, and his family expresses concerns Ventilation with lower tidal volumes as compared with
that his current state of disability would seem undignified traditional tidal volumes for acute lung injury and
and be undesirable to him. After a long discussion, we the acute respiratory distress syndrome. N Engl J Med.
reduce care to comfort measures and withdraw ventilatory 2000;342(18):1301–1308.
support to supplemental oxygen by tracheostomy mask 5. Esan A, Hess DR, Raoof S, et al. Severe hypoxemic re-
only. The patient dies later that day. spiratory failure: part 1—ventilatory strategies. Chest.
2010;137(5):1203–1216.
CONCLUSION
SUGGESTED READING
Hopefully this chapter has enriched readers’ understand-
Lumb AB. Nunn’s Applied Respiratory Physiology. 6th ed.
ing of the physiologic, pathophysiologic, and engineering
Philadelphia, PA: Elsevier Limited; 2005.
basis of mechanical PPV. With this strong foundation, MacIntyre NR, Branson RD. Mechanical Ventilation. 2nd ed.
variations on the currently widespread styles of ventila- Philadelphia, PA: Saunders Elsevier; 2009.
tion should be very understandable. As the cases illustrate, Raoof S, Goulet K, Esan A, et al. Severe hypoxemic respira-
there are numerous ways to apply ventilation technology, tory failure: part 2—nonventilatory strategies. Chest.
and even when we do it well, we may not be guaranteed a 2010;137(6):1437–1448.
good outcome. Perhaps the most ideal applications of this West JB. Respiratory Physiology: The Essentials. 7th ed.
technology will be to pause the process of dying, giving us Philadelphia, PA: Lippincott Williams & Wilkins; 2005.
DESIGN SERVICES OF

CHAPTER
55 Complications of Intubation:
Acute and Chronic
Charles J. Lin and Manuel C. Vallejo
INTRODUCTION closed claims study demonstrated that 80% of laryngeal

injuries occurred during routine intubation.3,4 Therefore,
Intubation is the most commonly used method of secur- under the best circumstances and in the hands of the most
ing a patient’s airway during surgical procedures and is a experienced operator, complications may still occur.
mainstay of management of patients in acute respiratory
failure or who have altered mental status. Complications
of endotracheal intubation can result from direct laryn-
FAILED OR MISPLACED INTUBATION
goscopy, from pressure of the endotracheal tube or cuff
on the airway and on surrounding structures, and from Failed or misplaced intubations are some of the most
extubation.1 There are numerous structures in the oro- commonly encountered complications of endotracheal
pharynx, laryngopharynx, larynx, and trachea that are intubation. Incorrect placement of the endotracheal tube
susceptible to potential damage (Fig. 55-1). This chapter may result in esophageal or bronchial intubations, which
discusses notable complications of endotracheal intuba- must be recognized and corrected promptly. Esophageal
tion, as well as their precipitating causes and perioperative intubation may be recognized simply by auscultation of
management. These can be subdivided temporally: acute air in the abdomen, and lack of breath sounds, or lack of
or chronic, depending on whether they occur at the time persistent end-tidal carbon dioxide (ETCO2) with venti-
of intubation or whether they occur secondary to pro- lation. Of note, transient ETCO2 can be detected despite
longed intubation.2 Table 55-1 provides a comprehensive an esophageal intubation if the patient recently consumed
list of acute and chronic complications; a number of these a carbonated beverage. Sequelae of esophageal intubation
are discussed in detail in this chapter. are serious including hypoxia, brain death, myocardial in-
farction, and cardiac arrest.5–7
Bronchial intubation occurs when the endotracheal
PREDISPOSING FACTORS tube is placed in one of the mainstem bronchi, usually on
the right due to its more vertical orientation as compared
Several factors are likely to increase the risk of pharyngeal with the left. Infants and children are at higher risk of
and laryngeal complications. These factors may be related bronchial intubation due to the smaller distance between
to the skills of the provider, the airway equipment, the pa- the vocal cords and carina. An endobronchial intubation
tient’s anatomy, the emergent nature of the intubation, un- can occur immediately after intubation, when the endotra-
anticipated difficulty encountered during intubation, or a cheal tube is advanced too far. Endobronchial intubation
combination of these. The provider plays a role in the risk only ventilates and oxygenates one lung, which leads to
of endotracheal intubation based on his or her knowledge, atelectasis, ventilation-perfusion mismatch, and hypoxia.
skill, and experience.2 In addition, the equipment used for If the patient has unequal breath sounds in both lungs, the
endotracheal intubation can affect the outcome. An inap- endotracheal tube can be slightly pulled back. During the
propriately sized endotracheal tube, or the use of stylets or surgery or in the intensive care unit, the endotracheal tube
bougies, increases a patient’s risk of airway trauma.2 The is also at risk of migrating into a bronchus when the pa-
provider’s initial evaluation of the airway is a key element in tient’s position is changed. For example, placing a patient
avoidance of, and preparation for, a difficult intubation and in the Trendelenburg position can advance a tube that
the airway trauma that may result from it. Patient-related was initially in the distal trachea into the right mainstem
risk factors for airway trauma related to endotracheal bronchus.8 Usually, this event presents as elevated airway
intubation include a small larynx, cervical spine pathol- pressures and oxygen desaturation. Knowing the original
ogy, and difficult airway as assessed by the Mallampati depth of the tube when correct placement was confirmed
score. It is also important to be mindful that routine in- can be useful for determining the length of endotracheal
tubation can cause trauma to the laryngeal soft tissues; a tube to pull back.
394

CHAPTER 55 ■ COMPLICATIONS OF INTUBATION: ACUTE AND CHRONIC 395
Thyrohyoid FIG U RE 55-1 Structures that are

muscle Genioglossus at risk of harm during endotracheal
muscle
Cricothyroid Hyoglossus muscle intubation.
muscle
(Adapted from Ferson D, Chi L,
Trachea Zambare S, et al. Safety and hazards
associated with tracheal intubation
and use of supralaryngeal airways.
In: Gravenstein N, Kirby RR, eds.
Esophagus Complications in Anesthesiology.
2nd ed. Philadelphia, PA: Lippincott
Superior laryngeal
nerve, artery, vein Williams & Wilkins; 2006:109–124,
with permission.)
Inferior pharyngeal
constrictor
External carotid artery
Lingual vein and artery

Hypoglossal nerve
Table 55-1 ESOPHAGEAL TEAR OR RUPTURE

Complications of Endotracheal Intubation Esophageal perforation is a rarely reported complica-
tion of endotracheal intubation that occurs during un-
intentional esophageal intubation.9–14 Most iatrogenic
Acute complications of endotracheal intubation
esophageal injuries occur during upper gastrointestinal
Failed intubation endoscopy and esophageal dilation and usually involve
Esophageal perforation the thoracic esophagus.15 However, esophageal injuries
Difficult intubation that occur secondary to endotracheal intubation are usu-
ally located in the cervical esophagus. The increased sus-
Hyperactive autonomic response
ceptibility of the cervical esophagus to injury is due to
Spinal cord injury the lack of a reinforcing longitudinal muscle layer and
Corneal abrasion the pressure of the cervical vertebrae on the esophagus
Trauma to oropharyngeal soft tissue during cricoid pressure and neck hyperextension.10 Hilmi
Dental injury et al10 published two cases reporting the occurrence of
Hoarseness and vocal cord damage subcutaneous emphysema after unintentional esopha-
geal intubation (Fig. 55-2). In both cases, perioperative
Tracheobronchial damage
endoscopy identified an esophageal tear in the posterior
Bronchospasm wall, in the cervical esophagus near the upper esophageal
Laryngospasm sphincter. Risk factors for esophageal perforation include
Passive reflux and aspiration operator experience, unanticipated difficult intubation,
Airway edema with postextubation obstruction and the use of a rigid stylet.10,16 The most common clini-
cal finding of esophageal perforation is subcutaneous em-
Chronic complications of intubation
physema in the neck or upper chest that becomes more
Tracheal stenosis obvious when the patient receives mask ventilation.10
Tracheoesophageal fistula The extent of the subcutaneous emphysema depends
Tracheomalacia on the amount of air that enters the esophagus; patients
who are readily ventilated will have less air entry into the
Sinusitis and nasal ulceration from nasal intubation
esophagus than patients who are difficult to mask venti-
Oral ulceration late. Appropriate diagnostic tests include a chest radio-
Laryngomalacia graph and endoscopy for definitive diagnosis. Depending
on the location, extent of the injury, development of

as esmolol before laryngoscopy can control hemody-

namic responses to endotracheal intubation and prevent
tachycardia.18
INJURY TO THE VERTEBRA(E)

OR SPINAL CORD
Injury to the spinal column or cord can occur with hy-
perextension of the cervical spine during intubation. In
its worst case, it can result in quadriplegia. Patients most
at risk of this complication include those with a history
of cervical spine fracture, previous surgery to the cervi-
cal spine, tumors of the cervical spine, spinal malforma-
tions, osteoporosis, and trauma with suspected instability
of the cervical spine.2 For patients in these categories, the
provider should consider fiberoptic intubation, or another
means of managing the airway that would avoid signifi-
cant cervical spine motion (see relevant chapters in the
F I GUR E 5 5 -2 Subcutaneous emphysema in supraclavicular book on fiberoptic bronchoscopy for intubation, optical
area. stylets, lightwands, prism/mirror-based devices, and rigid
(Reused with permission from Hilmi IA, Sullivan E, Quinlan J, fiberoptic devices).
et al. Esophageal tear: an unusual complication after difficult
endotracheal intubation. Anesth Analg. 2003;97:911–914.)
CORNEAL ABRASION
sepsis, and the patient’s overall medical condition, con- Corneal abrasion is a preventable complication of airway
servative nonsurgical management is generally preferred management that carries an incidence of 0.1% in nonoph-
unless complications arise.10 Conservative management thalmologic surgery, though the etiology is not always ap-
includes antibiotics, nasogastric suction, and total par- parent.19 This complication can be caused by objects on
enteral nutrition. the provider’s wrist or hanging from the provider’s neck or
uniform chest pocket such as jewelry, a wristwatch, or an
identification badge, resulting in direct trauma to the cor-
neal epithelium.20 One measure that can be used to protect
DIFFICULT INTUBATION the patient’s eyes during mask ventilation and intubation
is to tape the eyelids closed after induction and before
This important topic is discussed fully in other chapters of laryngoscopy. Soothing saline drops or methylcellulose
this book. (See Chapters 9–15.) drops overnight can manage a simple abrasion. For those
with severe pain or changes in visual acuity, an ophthal-
mology consultation should be obtained. Antibiotics are
AUTONOMIC HEMODYNAMIC RESPONSE usually not required, and patients are usually symptom-
free the following morning.
Both laryngoscopy and intubation can trigger the body’s
sympathetic response, resulting in an increase in circu-
lating catecholamines. This, in turn, can cause hyperten-
sion, various arrhythmias, increased intracranial pressure, TRAUMA TO THE OROPHARYNGEAL
and increased intraocular pressure. These complications SOFT TISSUE
could potentially lead to myocardial ischemia or infarc-
tion, congestive heart failure, or fatal arrhythmias.17 The incidence of oral and pharyngeal injury during en-
Risk factors for these complications include history of car- dotracheal intubation can be as high as 18%.21 Although
diovascular disease as well as prolonged laryngoscopy or not usually severe, trauma to the lips, teeth, tongue, and
multiple attempts at intubation. Medications frequently buccal mucosa may be painful and are of cosmetic concern
used to reduce the impact of these autonomic reflexes in to the patient. These types of injuries are more common
an adult include pretreatment doses of intravenous lido- with difficult intubations or poor laryngoscopic technique
caine (50 mg) or intravenous fentanyl (100 to 200 mcg). especially among beginners.22 Patients may complain of
The administration of short-acting beta-blockers such dysphagia or sore throat postoperatively. If the mucosal

lining of the posterior pharynx is disrupted, a pharyngeal Maxillary arch

abscess may develop.23
Central incisor
8 9
Lateral incisor 7 10
Canine 6 11
DENTAL INJURIES First premolar 5 12
Dental injuries are the most common complication of Second premolar 4 13
endotracheal intubation and the most common reason Right Left
for lawsuits against anesthesiologists.24–30 Retrospective First molar 3 14
data demonstrate that the incidence of dental injuries Second molar 2 15
ranges from 0.02% to 0.07%, but prospective studies
show that the incidence is higher ranging from 0.1% to Third molar 1 16
12% especially at hospitals with anesthesiology training Universal FDI
programs.21,31–33 The greatest risk occurs during direct la- Third molar 32 17
ryngoscopy, and the anterior maxillary teeth are the most
commonly damaged. This occurs when the proximal end Second molar 31 18
of the laryngoscopic blade is placed on the anterior max- Right Left
illary teeth, and the teeth are used as a fulcrum in an at- First molar 30 19
tempt to secure a better view.27 Another major cause of Second premolar 29 20
dental damage is the placement of an oral airway in the First premolar 28 21
oropharynx, which can expose vulnerable teeth to injury Canine 27 22
secondary to the forces of clenching, grinding, and mas- Lateral incisor 26 25 24 23
tication during emergence.34,35 A soft roll of gauze can Central incisor
be used instead; it should be placed on healthy posterior Mandibular arch
teeth to withstand excessive forces that can occur during
emergence.27 FIG U RE 55-3 Universal numbering system for adult
During the preoperative evaluation, the patient’s dentition.
dentition should be evaluated and any teeth that appear (Adapted from Yasny JS. Perioperative dental considerations
chipped, loose or previously repaired should be docu- for the anesthesiologist. Anesth Analg. 2009;108:1564–1573,
mented with the tooth numbered according to the uni- with permission.)
versal numbering system for adult dentition (Fig. 55-3).
Buffington and Vallejo36 developed a simpler method for
numbering teeth by focusing on the anterior teeth, the most If dental trauma occurs during intubation, the dental
likely damaged, and using a memory trick “6,11 ⫻ 2 ⫽ service should be consulted postoperatively. If the tooth
22,27” to help providers remember how to number teeth is dislodged, its retrieval is mandatory prior to placing
(Fig. 55-4). Tables 55-2 and 55-3 provide a list of charac- the endotracheal tube. Chest X-rays can be used to lo-
teristics that place patients at a high risk of dental injury. cate the missing tooth. The concern is that the dislodged
Teeth that have been restored with fillings, caps or crowns, tooth can be wedged into a bronchus. If the tooth cannot
or corrected with a root canal are still weaker than healthy be retrieved manually, a fiberoptic bronchoscope is used
teeth and are susceptible to fracture or dislodgement when to retrieve the tooth. Leaving the tooth in the pulmonary
an undue stress is applied to them.21,26,37 To prevent aspira- tree can lead to hypoxemia, lung collapse, and the forma-
tion and to aid the retrieval of dislodged dentition, loose tion of a lung abscess.1 If the tooth is loosened, it should
teeth can be secured by wrapping 3-0 silk suture around be secured with tape or suture in its original position. If
the gingival margins of the tooth and taping the suture to the tooth is avulsed, the decision to reimplant the tooth
the ipsilateral cheek (Fig. 55-5).27 Pediatric patients may is under the discretion of the anesthesiology team. The
have loose deciduous teeth that should be removed after benefit of immediate reimplantation is the increased like-
the induction to prevent the risk of a traumatic dislodge- lihood of successful retention; however, the concern with
ment causing an airway obstruction or harm to the under- reimplantation is the risk of aspiration. If the tooth is
lying permanent tooth. Several studies have examined the reimplanted, do not wipe or dry the root surface because
use of mouthguards to protect teeth during laryngoscopy. it contains a collagen network that is necessary for reim-
Some concerns about mouthguards are that the thickness plantation.39 If the tooth is not immediately reimplanted,
of the guard impedes visibility of the oral cavity and de- the preferable soaking solution is milk.40 The other al-
creases the amount of space in the mouth, and their use ternative is normal saline.40 The dental injury should be
may prolong intubation time with an increased risk of oral reported to the risk management department, and details
trauma.27 In fact, mouthguards have not demonstrated any of the incident should be documented on the patient’s
significant decrease in dental injury.38 chart.

F I GUR E 5 5 -4 Easy
tooth-numbering guide.
(Reused with permission from
Buffington CW, Vallejo MC. A simple
preanesthesia dental examination.
Anesthesiology. 2006;104:212–213.)
Patient-Specific Risk Factors of Dental Injury Anesthesia-Specific Risk Factors

of Dental Injury
Preexisting dental restorations (caps, crowns, bridges, General anesthesia
veneers, root canals, and dental implants)
Endotracheal intubation
Preexisting periodontal condition (loose tooth or
Difficult airway (Mallampati class 3 or 4, limited
teeth)
mouth opening, limited head extension, or limited
Chipped, cracked, or brittle teeth neck movement)
Age (young primary deciduous teeth, elderly) History of difficult intubation
Crowded anterior teeth Oral endoscopy
Isolated tooth or teeth
adhesion, vocal cord fracture, and arytenoid cartilage sub-

luxation. The etiology of these complications can be mani-
fold including acute trauma from endotracheal tube place-
ment or pressure on the posterior larynx from the balloon
or the endotracheal tube itself. Risk of intubation trauma
include abnormalities of laryngeal anatomy, repeated at-
tempt at laryngoscopy or intubation, perioperative en-
dotracheal tube movement, acid reflux, or endotracheal
tubes that are inappropriately large for the patient or have
a high pressure cuff.41 Acute laryngeal edema postextuba-
tion can be treated with nebulized racemic epinephrine.
When persistent, this problem should be evaluated by the
otolaryngology service, typically with fiberoptic laryngos-
copy. Figure 55-6 shows an example of vocal cord bow-
ing caused by trauma from an intubation.42 The authors’
F I GUR E 5 5 -5 Wrapping 8-0 suture around loose tooth. presumed mechanism for this damage was the use of an
(Reused with permission from Yasny JS. Perioperative dental oversized endotracheal tube that exerted pressure on the
considerations for the anesthesiologist. Anesth Analg. laryngeal mucosa and the recurrent laryngeal nerve caus-
2009;108:1564–1573.) ing subsequent deformation.
Damage to the arytenoid cartilage can occur during
THE MANY CAUSES OF HOARSENESS a routine or difficult intubation when the distal tip of the
IN AIRWAY MANAGEMENT endotracheal tube displaces the arytenoid cartilage either
anteriorly or inferiorly.1 In particular, patients with a past
Hoarseness is a postintubation complication with sev- medical history of systemic illness, including chronic renal
eral etiologies including laryngeal nerve injury, laryngeal insufficiency, Crohn disease, and acromegaly, who pres-
edema, vocal cord granuloma, vocal cord polyp, vocal cord ent with persistent hoarseness, sore throat, and dysphagia,

FIG U RE 55-7 Arytenoid cartilage subluxation is a risk of

F I GUR E 5 5 -6 Vocal cord bowing is a risk of tracheal tracheal intubation.
intubation.
(Reused with permission from Paulsen FP, Rudert HH,
(Reused with permission from Shimokojin T, Takenoshita M, Tillmann BN. New insights into the pathomechanism of
Sakai T, et al. Vocal cord bowing as a cause of long-lasting postintubation arytenoids subluxation. Anesthesiology.
hoarseness after a few hours of tracheal intubation. 1999;91:659–666.)
Anesthesiology. 1998;89:785–787.)
should be evaluated for possible arytenoid cartilage dam- complication that may lead to respiratory failure and car-
age (Fig. 55-7).1,43 A study by Paulsen et al on the larynx diovascular collapse from tension pneumothorax or ten-
of cadavers suggested an inapparent mechanism for ary- sion pneumomediastinum. The risk factors associated with
tenoid cartilage subluxation. Instead of the displacement tracheobronchial rupture include operator experience,
arising from the initial trauma, the subluxation is due to unanticipated difficult intubation, inappropriate use of a
the formation of fractures of the cricoarytenoid joint lead- stylet, and overinflation of the endotracheal tube cuff.51–53
ing to the fixation of these cartilage pieces in an abnormal A high level of suspicion should be maintained when a
position.43 In addition, one case report has described the patient with the aforementioned risk factors acutely devel-
posterior lateral displacement of the arytenoid cartilage by ops head and neck emphysema, hemoptysis, hypoxia, and
pressure from the shaft of a double-lumen endotracheal elevated airway pressures. A patient who is suspected of
tube.44 Arytenoid subluxation is a rare complication, oc- tracheobronchial rupture requires an evaluation to visual-
curring in only 0.023% of patients, but it has serious im- ize the site of injury.52 The decision to pursue conservative
plications including possible permanent hoarseness and or surgical management depends on the site of the tear and
compromised airway protection.45 Evaluation by the oto- the patient’s underlying medical condition; case reports
laryngology service would include indirect and direct la- have documented the use of conservative management for
ryngoscopy, CT scan, and electromyography of the larynx. treating small uncomplicated tears in stable patients.49,54,55
AIRWAY PERFORATION/ PNEUMOTHORAX

TRACHEOBRONCHIAL LACERATION Pneumothorax can be a complication of endotracheal in-
AND RUPTURE tubation caused by direct trauma to the esophagus or air-
way, high airway pressure causing alveolar rupture, or ex-
Tracheobronchial rupture is a rare complication of endo- trathoracic trauma.56–59 One of the two cases of esophageal
tracheal intubation with an estimated incidence of 0.05% perforation reported by Hilmi et al resulting in a pneumo-
to 0.37%, though it is more commonly found in the set- thorax (Fig. 55-8). An elevated peak inspiratory pressure
ting of blunt chest trauma.46–50 This is a life-threatening greater than 40 cm H2O is a widely accepted threshold

pulmonary function testing.41 It is important to note that

ulcerations that progress to tracheal erosions can form a
tracheoesophageal fistula and/or tracheomalacia, both of
which incur a significant risk of tracheal collapse.41 A tra-
cheostomy is usually recommended for a prolonged intu-
bation that is expected to last longer than 2 to 10 days, in
order to reduce the risk of laryngeal injury and the risk of
ventilator-associated pneumonia from micro aspiration of
oral secretions.62
CONCLUSION
Endotracheal intubation is so routine and safe that it is
easy to assume that the intubation will have no lasting
consequences. Usually that assumption is true, but an ad-
verse event can still occur in the hands of a skilled practi-
tioner during a routine intubation. Complications related
to intubation are significant, and it is paramount that
F I GUR E 5 5 -8 Subcutaneous emphysema and those who manage airways understand these risks. This
pneumothorax. chapter has outlined notable risks related to intubation
(Reused with permission from Hilmi IA, Sullivan E, Quinlan J, with the goal of teaching providers how to prevent, pre-
et al. Esophageal tear: an unusual complication after difficult dict, recognize, and treat complications.
endotracheal intubation. Anesth Analg. 2003;97:911–914.)
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trachea.41 The subsequent formation of scar tissue and usual complication after difficult endotracheal intubation.
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CHAPTER
Care of the Patient with a

Surgical Airway: An Approach
56 cn
to Emergency Interventions
Elizabeth H. Sinz
SURGICAL AIRWAYS surgically altered can lead to poor decision making in an

airway crisis. The most likely problems one will encounter
Tracheostomy, tracheotomy, and cricothyroidotomy are differ somewhat with each type of surgical approach.
surgically created airway openings directly into the tra-
chea below the vocal cords. In many ways, the airway is
greatly simplified because the upper airway has been cir- OXYGENATION AND VENTILATION
cumvented; nevertheless, many physicians and other care-
IN A PATIENT WITH A TRACHEOSTOMY
givers are stymied when they encounter a problem with
a surgical airway. Understanding the anatomy resulting A tracheostomy generally requires no equipment, such as
from the different surgical approaches and knowing how a tube, to remain patent. Patients often wear a cloth cover
to manage some common complications can alleviate the to preserve their appearance and protect their airway from
fear and frustration associated with airway compromise in dust and debris. Healthcare providers must be careful not
this patient population. to overlook the patient’s actual airway in a medical emer-
A tracheostomy, or tracheal stoma, is most often cre- gency. Oxygen given via nasal cannula or face mask, for
ated when a patient undergoes a laryngectomy. In this example, will not reach the patient’s lungs; supplemental
case, the trachea is diverted to the neck, and there is oxygen must be administered over the tracheal stoma to
no connection between the trachea and any upper airway be effective.
structures. The only way to access the lungs of these Positive pressure ventilation provided by a normal
patients is via the tracheal stoma (Fig. 56-1 A and B). bag-valve-mask apparatus to the face will only inflate the
A tracheotomy is a hole in the trachea that is made sur- patient’s stomach. If a patient with a tracheostomy re-
gically through the front of the neck. The patient’s upper quires positive pressure ventilation there are two options:
airway remains in continuity with the trachea, although de- (1) application of a small mask to the neck over the tra-
pending on the reason for the procedure, the upper airway cheal opening, or (2) insertion of a cuffed tube (either an
anatomy may or may not be normal. There are two ways endotracheal tube or a tracheotomy tube) into the ostomy
to access the lungs of these patients: either through trache- with positive pressure via this tube.
otomy or through the upper airway (Fig. 56-2 A, B and C).
In an airway emergency, the trachea may be surgically
approached through the cricothyroid membrane, using a OXYGENATION AND VENTILATION
procedure called a cricothyroidotomy. (See Chapters 36, IN A PATIENT WITH A TRACHEOTOMY
Cricothyrotomy, and 37, Wire-Guided Cricothrotomy)
This creates an opening into the airway through the neck A tracheotomy will typically close over time unless there
and cricothyroid membrane just below the vocal cords. is a tube or a plug in place to keep it open. People with a
This is a temporary airway, typically created under emer- tracheotomy tube who are breathing spontaneously may
gency conditions to provide oxygen to the patient until a be breathing through their nose and mouth or through
formal tracheotomy or other airway access can be obtained, their tracheotomy or both. If in respiratory distress,
although this is somewhat controversial.7 The upper air- the patient may be experiencing a blocked or partially
way of the patient is intact, but the reason for requiring blocked airway (upper or lower) or they may need as-
an emergency surgical airway is often due to abnormal or sistance with ventilation due to poor ventilatory mechan-
injured upper airway structures, so it may be very difficult ics or acute illness (ie, pneumonia or pulmonary edema).
or impossible to approach the trachea from above. The underlying cause of respiratory distress should be
Although these different approaches may not seem determined quickly so that the proper treatment can be
complicated, failure to recognize how the trachea has been initiated early.3
403

F I GUR E 5 6 -1 A Tracheostomy: surgical

opening into the trachea through the neck,
with the tracheal mucosa being brought into
continuity with the skin, often permanent.
B Patient with a tracheostomy. This patient has
undergone a laryngectomy and has no connec-
tion between his upper airway structures (nose
and mouth) and his lungs. Note the lower po-
sition on the neck compared with a typical tra-
cheotomy and the lack of a tracheotomy tube,
plug, or other stent to maintain patency. B
CUFFED TUBES VERSUS NONCUFFED airway, and making normal speech possible by externally
occluding the tube.2,11
TUBES Without the seal provided by a cuff, positive pressure
Patients who require positive pressure ventilation through ventilation will be ineffective through a tracheotomy tube.
a tracheotomy tube should have a cuffed tracheotomy tube If a patient develops respiratory compromise requiring
in place. These tubes have a pilot balloon attached to the positive pressure ventilation, either with a bag-valve ap-
cuff that hangs down on the outside (Fig. 56-3). It is possi- paratus or a ventilator, the cuff must be inflated to create
ble for these cuffs to rupture or leak and no longer provide a seal. If the tube in place is fenestrated, the inner cannula
a seal between the tube and the trachea. More commonly, must be inserted to occlude the fenestration. A third op-
the patient who no longer requires positive pressure vention is to occlude the opening of the tracheotomy tube
tilation will have the cuff deflated or a new tube may be and apply positive pressure from above using a face mask.
placed that has no cuff. These long-term tubes are plastic If none of these options are viable, the tracheotomy tube
or metal and may have fenestrations to allow air to flow should be removed and a cuffed tube should be inserted ei-
through as well as around the tracheotomy tube, thereby ther through the hole in the neck or through the upper air-
allowing breathing through the vocal cords and upper way using traditional or alternative intubation techniques.

CHAPTER 56 ■ CARE OF THE PATIENT WITH A SURGICAL AIRWAY 405
FIG U RE 56-2 A Tracheotomy: incision or

opening of the trachea with no implication of
permanence. B Patient with a tracheotomy tube
in place. This patient has an incision through his
neck into his trachea, but his upper airway re-
mains intact. C The tracheotomy tract is mature
2 and remains open when the tracheotomy tube
is removed.
3

F I GUR E 5 6 -3 A cuffed tracheotomy tube

and its components: Outer cannula with
flange; Inner cannula; Obturator (to ease
placement, then removed)
POTENTIAL COMPLICATIONS however, if the occlusion is not due to radiopaque material

the study may not be helpful.
It is helpful to know the common causes of respiratory com- Inadvertent decannulation is a life-threatening com-
promise in patients with surgically created airways.4,6,8,10,11 plication. If there is no air flow through or around the tube,
Early complications of tracheotomy include subcutaneous the circumstances require immediate action or the patient
or mediastinal emphysema and pneumothorax. Because will asphyxiate. In this case, the tube may be completely
many of the patient’s protective functions are compromised obstructed or it may have become displaced in a false pas-
due to bypass of the upper airways, continued insertion of sage between the skin and the trachea. This is particularly
a foreign body, and interruption of ciliary clearance and common in a patient with a recent tracheotomy in a thick
impaired cough, patients with chronic surgical airways are or short neck.9 In this case, the suction catheter will not
at increased risk of pulmonary infections A chest X-ray is pass and attempts to ventilate will be met with very high
often a helpful diagnostic tool, but should not delay thera- resistance. The tracheotomy tube should be removed im-
peutic interventions in a true emergency. mediately and replaced with a patent tube either through
Occlusion can occur as the result of equipment the tracheotomy hole in the neck or via the upper airway
problems, foreign body aspiration, or from the patient’s using traditional or advanced intubation techniques.11 New
own secretions or blood. If a foreign body is aspirated, it tracheotomies will often have stay sutures attached to the
should be removed if possible; if this cannot be done and tracheal cartilage to assist with replacing the tracheotomy
the patient is in grave distress, pushing the object distally tube. If tracheal intubation is not possible, mask venti-
may be lifesaving. If the tube is intentionally occluded by lation with a face mask, or alternative advanced airways
a mechanical plug or a speaking valve (passy muir valve), such as a laryngeal mask airway or esophageal airway (ie,
removing this may alleviate the problem. King tube or Combitube) should be attempted. Effective
Dried blood or secretions can build up inside or positive pressure ventilation from above may require oc-
around the tip of the plastic or metal tube and can be clusion of the tracheotomy hole with a finger. A retrograde
difficult to dislodge, even with suction. In addition, the wire passed through the tracheotomy hole that passes out
continual irritation of the artificial airway can lead to of the upper airway may assist with placement of an ETT
granulation tissue formation, often at the tip of the tube, from above. (See retrograde wire chapter.)
which can eventually cause a partial or total obstruction.11
This can sometimes lead to a “ball-valve” effect that can A patient with a tracheostomy following a laryngectomy
has no connection between his nose or mouth and his tra-
be particularly problematic, leading to difficulty exhaling.
chea and lungs. Any ventilation approach via the upper
A suction catheter should be used to remove airway will be unsuccessful.
the material blocking the airway; sometimes it may push
the blockage aside or down. Determining the cause of In all cases, ventilation is best confirmed with contin-
the patient’s problem is easiest with a bronchoscope uous waveform (one word) capnography. Bilateral breath
passed through the tube to see what is causing the block- sounds must be discerned with care because the likeli-
age.1,5,9 Occasionally an X-ray will reveal a foreign object; hood of passing a tube too deep and entering one of the

CHAPTER 56 ■ CARE OF THE PATIENT WITH A SURGICAL AIRWAY 407
mainstem bronchi is increased due to the relatively short subsequent interventions based on the information you
distance between the tracheotomy and the carina. Other obtain from each maneuver. Avoid repeating unsuccessful
indications of successful airway placement include chest maneuvers.
rise and patient response to ventilation. With knowledge of the patient’s anatomy after a sur-
gical airway procedure, the best approach for alleviating
respiratory distress can be quickly ascertained.
BLEEDING
Bleeding can occur within hours or days of placement of CONCLUSION
a surgical airway, or it can occur much later due to ero-
sion of the tube into vascular structures or from trauma There are a variety of surgical approaches to the airway.
from suctioning.6,8,9,10 The most immediate problems with Understanding the nature of the surgery, the anatomy of
bleeding are airway or tube obstruction due to clots and the patient’s airway, and whether or not a connection re-
“drowning” due to blood filling the lungs. It is uncom- mains between the upper airway and the lungs is impera-
mon, but possible, for a patient to exsanguinate from up- tive when assessing respiratory complaints or emergencies
per airway bleeding.11 If the bleeding is from the upper in patients with a surgical airway. Other common post-
airway, it may be helpful to place the cuff distal to the operative complications include dislodgement, bleeding,
bleeding site to keep the blood from entering the lungs. obstruction due to clot, mucous, or foreign body, and
This can be achieved by placing a longer tracheotomy tube granuloma tissue formation.
or by replacing the tracheotomy tube with an endotracheal
tube. As the upper airway may be filled with blood, this
maneuver may be quite challenging and should only be REFERENCES
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Wilkins; 2009: 945–954.
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Clots should be aggressively suctioned, and though hopkinsmedicine.org/tracheostomy/about/complications.html.
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or poorly understood artificial airway, the tension in- 8. Bhatti N, Tatlipinar A, Mirski M, et al. Percutaneous dila-
creases exponentially. tion tracheotomy in intensive care unit patients. Otolaryngol
Head Neck Surg. 2007;136(6):938–941.
“The definition of insanity is doing the same thing over and
9. Kost KM. Endoscopic percutaneous dilatational trache-
over and expecting a different result.” Source unknown
otomy: a prospective evaluation of 500 consecutive cases.
Approaching the problem in a methodical way will Laryngoscope. 2005;115(10 Pt 2):1–30.
increase the chances of a successful outcome. Calling for 10. Goldenberg D, Ari EG, Golz A, et al. Tracheotomy com-
specific, specialist help early is critical, but it may not be plications: a retrospective study of 1130 cases. Otolaryngol
Head Neck Surg. 2000;123(4):495–500.
possible to wait for help to arrive before acting. Providing
11. Engels PT, Bagshaw SM, Meier M, et al. Tracheostomy:
oxygen to the patient is the primary goal. A suction cath- from insertion to decannulation. Can J Surg. 2009;52(5):
eter or bronchoscope can be helpful for both diagnosis and 427–433.
sometimes treatment. Act quickly, stay calm, and tailor

Index
Page numbers followed by a ‘t’ indicate table while those followed by an ‘f’ indicate figure respectively.
A Anesthesia trigeminal nerve, 56–57

for airway management, 53t, 377–378 vagus nerve, 58–60
Abscesses, difficult airway management in, FOBs and, 177 Awake oral fiberoptic intubation, 53t
115, 118f, 119f IV general anesthetic agents for, 50, 51t
Achi Corp., 191 for tracheal intubation, 50 B
Acute and chronic complications of Anesthesia gas machine (AGM), 344
endotracheal intubation, Anesthetics, local, 56 Bag-mask-ventilation (BMV), 1, 204–205
395t. See also Endotracheal Anterior ethmoid nerve, 56 airway and mask technique, 107
intubation, complications of Antisialogogues, 55 “bagging by feel,” 107
Acute respiratory distress syndrome Apert syndrome, 295f face masks for, 15f
(ARDS), 392 APRV. See Airway pressure release oropharyngeal airways to assist with, 15f
Adults, obstructive sleep apnea (OSA) in, ventilation (APRV) Bainton laryngoscope blade, 372f
361–369, 363–367f ARDS. See Acute respiratory distress “Balloting” ETT cuff, 45, 48f
Agents for preprocedural sedation, 51t syndrome (ARDS) Bariatric surgery and morbid
Air-Q laryngeal mask airway (LMA), 214, Arndt blocker/Fogarty catheter placement, obesity, 370–374
306–307 328–329 Baseline variable, 383
Airtraq device, 127–129, 128f, 306 loading Arndt BB, 329f BBs. See Bronchial blockers (BBs)
grade 1 view of glottis through placing in mannikin’s left mainstem Beckwith–Wiedemann syndrome, 304f
viewfinder, 132f bronchus, 330f Bedside airway assessment methods
performing laryngoscopy with, 132f in right mainstem bronchus of intubating cone beam computed tomography
Airway. See also Bedside airway assessment mannequin, 330f (CBCT), 76–77, 77f
methods; Difficult airway; Arndt Emergency Cricothyrotomy craniofacial phenotyping, 81–85
King LT airway; Pediatric Set, 273 ultrasound (US) imaging, 77–80
airway anatomy and approach; Arthritis/bony hypertrophy, 118, 124f, 125f Belscope blade, 33t, 127, 129
and Williams airway Aryepiglottic folds (AEF), 9f Benzocaine, 56
bag using in ICUs, 352f ASA. See American Society of Benzodiazapines, 55
Berman airway, 145, 148f, 182 Anesthesiology (ASA) Berman airway, 182
exchange catheters, 133 Aspiration risks, 375, 376–377 Berman intubating airway, 145, 148f
or neck masses, 294t Assist/control (A/C) mode, of ventilation, Bilevel continuous positive airway pressure
Ovassapian airway, 182 386 (CPAP), 387
pressures, in jet ventilation, 342 Assisted Mechanical Ventilation Bimanual laryngoscopy, 8, 37
sounds/auscultation, 295 (AMV), 386 Bivona Laser endotracheal tubes, 334
Airway edema, 375 Atlanto-occipital (A-O) extension, 38f, 65f Bizzarri-Giuffrida laryngoscope, 29, 32f, 33t
with postextubation obstruction, 395t and cervical flexion, 65 Blades
Airway pressure release ventilation (APRV), Atomizers, 180f curved, 37, 42–43
387–388, 388f Atropine, 55 retraction, in laryngoscopes, 29–34
Alpha 2 antagonist, 56 Auscultation in axillary area, 49f straight, 38, 41, 42–43
Aluminum foil, 334 Awake intubations Blind nasotracheal intubation (BNTI)
Ambu Aura-I, 214 anterior ethmoid nerve, 56 advancing ETT into glottis, 143f
Ambu AuraOnce, 204, 206f antisialogogues, 55 complications, 144
American Society of Anesthesiology (ASA) consent, 55 concept, 139
airway management training, 96, 97 glossopharyngeal nerve, 57–58 contraindications, 144
definition of difficult mask greater and lesser palatine nerves, 57 dilating the nose with nasal
ventilation, 61 intravenous sedation, 55–56 airways/lubricants/
difficult airway algorithm, 87, 89f, 90 local anesthetics, 56 vasoconstrictors, 141f
AMV. See Assisted Mechanical neuroanatomy of nasopharynx, 56f evidence, 139
Ventilation (AMV) preparation, 55–56 indications, 144
Amyloidosis, airway obstruction in, 126f recurrent laryngeal nerve, 59–60 insertion of ETT along floor of nose, 141f
Anatomic abnormalities, difficult airway regional anesthesia blocks for, 55–60 placing ETT in position in
management and, 109 superior laryngeal nerve, 58–59 hypopharynx, 142f
408
Orebaugh_Index.indd 408 18/07/11 5:26 PM

INDEX 409
practicality, 144 Cardiopulmonary resuscitation, ETC in, 199 anthropometric features, 83f
preparing for, 140f Carina, as seen through FOB, 186f, 316f of bedside airway assessment, 81–85
procedure, 139, 144 CBCT. See Cone beam computed laser scans of life-size normal and
tube misdirection in, 142f, 143f tomography method (CBCT) abnormal clay heads, 85f
Blind orotracheal intubation CCM. See Critical care medicine (CCM) Polhemus FAST SCAN, 81f
complications, 149 Cervical flexion registration process, 81, 82f
concept, 145 evaluation of, 36, 37f, 38f surface and linear distances between
contraindications, 149 thoracic flexion, 38f anthropometric points of
digital intubation cadaver specimen, 146f Cervical spine normal and obese clay head, 84t
ETT advancing through glottis, 147f anomaly in Klippel-Feil syndrome, Vivid 900 scanner, 81f
evidence, 145 difficult airway management Craniofacial structure, 294
indications, 148 in, 109, 113f Cricoid pressure, 377
insertion of ETT, 147f FOB with injury in, 178 Cricothyroid membrane (CTM), 167, 231, 233
lifting epiglottis, 146f fracture/dislocation, difficult airway in cadaver specimen, 233f, 234f
practicality, 148 management in, 115, 122f enlarging incision in, 269f
BMV. See Bag-mask-ventilation (BMV) range of motion, 65 enlarging with scalpel, 275f
BNTI. See Blind nasotracheal intubation Cetacaine spray, 56 horizontal incision in lower portion
(BNTI) Chest radiography, tube localization and, 45 of, 269f
Bonfils Retromolar Intubation Choanal atresia, 294t making horizontal incision through, 271f
Fiberscope, 161 Choi blade, 29, 32f, 33t needle insertion in retrograde intubation,
Bougies and airway stylets Chronic complications of endotracheal 168f, 169f
bougie placed into esophagus, 137f intubation, 395t. See also needle puncture through, 275f
complications, 136 Endotracheal intubation, palpation of, 268f
concept, 133 complications of puncture of, 234f, 236f
contraindications, 136 Chronic obstructive pulmonary disease using Trousseau dilator to open incision
ETT inserting over GEB, 136f (COPD), 21 through, 271f
evidence, 133–134 Ciaglia Blue Rhino, 283 Cricothyroidotomy procedure, 403
indications, 134 Cisatracurium, 51t Cricothyrotomy
insertion of bougie into trachea, 136f Clarus Medical, 161, 164, 166 complications, 270
intubation through LMA and ILMA C-MAC Storz, 191, 196, 197t concept, 265
with, 239–242 and conventional MAC blade, 194f confirming ETT or tracheostomy tube
placing ETT over bougie, 137–138f CMV mode. See Continuous mandatory position in airway, 270f
practicality, 134 ventilation (CMV) mode contraindications, 270
preparation for direct laryngoscopy, 134 CO2, in esophageal intubation, 45 cricothyrotomy set, 267f
procedure, 134 Cobra Perilaryngeal Airway (PLA), 227f dissecting cadaver specimen, 268f
Bradycardia, 56 description, 227 enhancing cricothyrotomy before placing
Breaths, types of, 385 evidence, 227 dilator, 269f
Bronchial blockers (BBs), in thoracic in operating room, 227 evidence, 265–266
surgery. See also Arndt procedure, 227–228 grasping larynx while palpating
blocker/Fogarty catheter Cone beam computed tomography method CTM, 267f
placement; Univent tube (CBCT) horizontal incision in lower portion of
placement of bedside airway assessment, 76–77, 77f CTM, 269f
advantages, 329 Congenital anomalies, conditions indications, 268, 270
concept, 328 predisposing to difficult inserting tracheal tube into cricothyroid
disadvantages, 329 airway management, 109 interval, 269f
DLTs and, 321, 323 Congenital subglottic stenosis, 113f inserting tracheostomy tube or ETT into
evidence, 328 Continuous mandatory ventilation (CMV) the opening, 271f
indications, 329 mode, 386 making horizontal incision through
practicality, 329 Continuous positive airway pressure CTM, 271f
preparations, 328 (CPAP), 26, 107, 387 making midline vertical incision
Bronchoscopic view inside lumen of Conus elasticus, 265 over thyroid and cricoid
LMA, 212f Cooke Critical Care, 273 cartilages, 270f
Bronchospasm, 390 Cook Inc. retrograde intubation, 168, 168f network of veins evident in subcutaneous
Bullard laryngoscope intubation, 191, 194f, COPD. See Chronic obstructive pulmonary tissue, 266f
197t, 306 disease (COPD) palpation of CTM, 268f
Corneal abrasion practicality, 268
C endotracheal intubation complication, 396 procedure, 266
Covidien, 321 standard tracheostomy set, 267f
Cancer CPAP. See Continuous positive airway using Trousseau dilator to open incision
laryngeal, difficult airway management pressure (CPAP) through CTM, 271f
in, 115, 120f Cranial nerve V. See Trigeminal nerve Cricotracheal ligament, insertion of needle
supraglottic, difficult airway management Cranial nerve IX. See Glossopharyngeal at, 175f
in, 115, 119f nerve Critical care medicine (CCM), 97, 103
Capnography, 45, 47f Craniofacial phenotyping airway assessment, 351–353
Carcinoma, difficult airway management in, 3-D craniofacial laser scanning with airway bag using in ICUs, 352f
115, 119–120f 2-D photography and surface approach to airway, 353–355, 354f
Cardiogenic pulmonary edema, 21, 26 measurements, 84f complications, 355
DESIGN SERVICES OF

410 INDEX
Critical care medicine (continued) airway management outside of operating operator views of the glottis, 7f
personnel and equipment, 351 room, 67 orientation, 1
pharmacology, 353 cervical spine range of motion, 65 paraglossal straight blade approach, 42f
postextubation laryngeal edema, 355 computerized facial structure analysis, paraglottic laryngoscopy, 42f
preoxygenation, 353 70–74 “peardrop” phenomenon, 1, 5f
routine and difficult airway equipment, 352t Cormack-Lehane laryngoscopic poor view of larynx, 131f
setting, 351 view, 62, 63f positioning for, 8–9, 36–43
Critical Care Medicine Multidisciplinary history of, 62 preparation, 35–36, 134, 135f
Training Program, 107 inter-incisor distance (IID), 65 with prism on 3 Mac blade, 131f
Crouzon syndrome, 295f Mallampati classification, 62–65 relationship of blade tip to median fold of
“C” shaped laryngoscopes, 29 obesity, 66 hyoepiglottic ligament, 10f
CTM. See Cricothyroid membrane (CTM) photographic reconstruction of retraction blades, 29–34
Cuffed tracheotomy tube, 404, 406f head, 71f, 72t “Robin Hood hat,” 6, 9f
Curved blades, for direct laryngoscopy, 37, 42–43 thyromental distance (TMD), 65–66 sniffing position, 36, 39f
“Cycles per minute” (cpm)/Hertz (Hz), 340 upper lip bite test (ULBT), 66–67 suboptimal elevation of epiglottis, 8f
variations in facial appearance, 73f, 74f sweeping tongue to left with laryngoscope
D Difficult mask ventilation (DMV), 14 blade, 39f
definition, 61 view into mouth, 3f
DAM. See Difficult airway management (DAM) impossible mask ventilation (IMV) view of glottis with external laryngeal
DCI video system, 34 and, 61–62 pressure, 40f
Decision making in difficult airway Difficult tracheal intubation (DTI), 81 view of glottis without external laryngeal
management, 87–95 Digital intubation, 145, 147, 146–147f pressure, 40f
airway management requirements Dilaudid, 55 X-ray in supine and sniffing positions
differences, 91t Direct laryngoscopy (DL). See also during, 1, 2f
difficult airway management algorithm, 89f Pediatrics, adjuncts to direct Disposable clear blade, Pentax AWS and, 193f
emergency medicine airway management laryngoscopy in; Pediatrics, DL. See Direct laryngoscopy (DL)
algorithm, 92–95f direct laryngoscopy in; DLTs. See Double-lumen endotracheal
preoperative airway physical examination Retraction blades for direct tubes (DLTs)
components, 88t laryngoscopy; Siker blade; and DMV. See Difficult mask ventilation (DMV)
suggested contents of portable storage Video laryngoscopes Dorsal tongue, 1
unit, 91t anatomy of, 1–11 Double-angle blade, 29
techniques for difficult airway axial manipulation on glottic exposure, 38f Double-lumen endotracheal tubes (DLTs)
management, 88t axial positioning during blade insertion, 36 Carlens tube, 321, 322f
Dental abnormalities, difficult airway bimanual laryngoscopy, 8 complications, 326
management in, 109, 110f, 111f bougie/airway stylet, preparation concept, 321
Dental abscess, difficult airway management with, 134, 135f confirmation of position of left-sided
in, 115, 119f concept, 35 DLT, 325
Dental injuries Cormack-Lehane laryngoscopic view, contraindications, 326
anesthesia-specific risk factors of, 398t 62, 63f endobronchial cuffs of right-sided
endotracheal intubation complication, 397 credulity of flexion-facilitation, 105, 107 DLTs, 322f
patient-specific risk factors of, 398t direction of forces applied, 40f evidence, 321, 323–324
Dexmedetomidine, 53t, 56 dorsal tongue, 1 fiberoptic view of carina and correct posi-
DI. See Difficult intubation (DI) endotracheal tube (ETT) placement, tioning of left-sided DLT, 323f
Diagnostic and therapeutic fiberoptic 43, 43f indications, 326
bronchoscopy. See Fiberoptic evidence, 35 left-sided DLTs, 322f
bronchoscopy external laryngeal pressure, 40f placement, 324–325
Diazepam, 51t, 55 factors, weigh against incorporation of practicality, 325
Difficult airway. See also Difficult airway first pass approach, 104–105t preparation, 324
management (DAM) glottis-like appearance of size estimation, 324t
definitions, incidence, and predictors esophageal, 41f sizing, 324
of, 61–67 head-elevated position, 11f special situations, 326
fiberoptic bronchoscopes (FOBs), 178 hyoid bone and thyroid cartilage, 9, 11f Down syndrome, 294, 361
ILMA for management of, 214–223 hypertrophic lingual tonsils, 1, 3f enlarged tongue, difficult airway
retrograde intubation in, 167 improving, success in difficult cases, and management in, 113f
Difficult airway device techniques and comments, 106t Driving pressure, in HFJV, 341–342
King LT use as, 226 inappropriate “levering” force, 41f DTI. See Difficult tracheal intubation (DTI)
Difficult airway management (DAM). indications for tracheal intubation, 35t
See also Decision making in with insertion of bougie into trachea, 136f E
difficult airway management intubation equipment, 36f
algorithm, ASA, 61f, 87, 90 keys to first pass success, 35 ED. See Emergency department (ED)
decision making in, 87–95 laryngeal skeleton, 6f Edema, difficult airway management, 115,
examples and conditions predisposing to, learning curve intubation, 104f 123–124f
109–126 mouth and tongue anatomy, 1–8 ELM. See External laryngeal manipulation
fiberoptic bronchoscopes (FOBs), 87 mouth opening, 36–37 (ELM)
pathology and, 114 mouth opening using fingers in scissors EMA-T device, 14, 19f
simulation program, 96–101 configuration, 39f Emergency department (ED)
training in, 96–101 mouth opening using head extension, 39f airway assessment, 357–359
Difficult intubation (DI) muscles of tongue, 4f airway management in, 91t
DESIGN SERVICES OF

INDEX 411
difficult airway in, 67 inserting lightwand, 154f, 155f ETT. See Endotracheal tube (ETT)
equipment, 359 inserting over GEB, 136f Expiratory positive airway pressure
intubating patient in trauma resuscitation inserting over guide catheter, 173f (EPAP), 26
area, 358f insertion along floor of nose, 141f Extended Mallampati score (EMS), 63
intubating patient with insertion into glottis, 147f External laryngeal manipulation (ELM), 8,
videolaryngoscope, 358f insertion into pharynx, 158f 37, 40f, 106t
lightwands in, 151 in the larynx, 175f Extracorporeal Shock Wave Lithotripsy
retrograde intubation in, 167 laser airway surgery and, 333–334 (ESWL), 347
setting, 357 lighted stylet with, 153f F
trauma patient arrives at ED after failed loaded, locked into position, trachlight, 158f
intubation in field, 359f passing into trachea, 219f Face mask
use of ILMA in, 215 Pentax AWS with, 193f application in unconscious patient, 18f
Emergency medical technicians (EMTs) in place and ventilation re-initiated, 221f for bag-mask ventilation, 15f
supraglottic airway device (SGA) by, 226 placed through ILMA, 218f detail of application, 18f
Emergency medicine airway management placement, 43, 43f, 50 procedure, 14, 15–19f, 20
algorithms, 92–95f placing over bougie, 137–138f two-person mask technique, 18f
Emergent airway management, ETC in, 199 placing over FOB into larynx, 189f using “lower lip” placement, 19f
EMS. See Extended Mallampati score (EMS) removal of stylet from, 159f Facial asymmetry, 295f
EMTs. See Emergency medical stabilizing, LMA removal and, 220f Facial fractures, difficult airway
technicians (EMTs) Endotracheal tube introducers (ETI), 103 management in, 115, 122f
Endotracheal intubation complications Enlarged breast tissue, in parturient Facial hair, difficult airway management
acute complications of, 395t patients, 375 in, 109, 112f
airway perforation/tracheobronchial EPAP. See Expiratory positive airway Facial/orthodontic hardware, 294t
laceration and rupture, 399 pressure (EPAP) Facial skeleton, difficult airway management
anesthesia-specific risk factors, of dental Epidural catheter, 167 in, 114, 114f
injury, 398t “EpiFlip,” 6, 8 Failed/misplaced intubations
arytenoid cartilage subluxation, risk of Epiglottis, 291, 293 endotracheal intubation complication, 394
tracheal intubation, 399f difficult airway management and, 109, 112f Fastrach, LMA of North America, 214
autonomic hemodynamic response, 396 as seen through FOB during oral Fentanyl, 51t, 55, 396
chronic complications of, 395t approach, 185f Fibercapnic intubation, 178
corneal abrasion, 396 leveraged elevation, with curved blade, 6, 8 Fiberoptic awake intubation
dental injuries, 397 Miller blade lifting, 31f nasal, equipment for, 179f
difficult intubation, 396. See also Difficult Epiglottitis, 114–115, 116f oral, equipment for, 179f
intubation (DI) Epinephrine, 56 Fiberoptic bronchoscopic intubation (FOB), 87
easy tooth-numbering guide, 398f Erythema TTJV and, 260–262
esophageal tear, 395–396 in acute epiglottitis, 116f Fiberoptic bronchoscopy (FOB), 45
failed/misplaced intubation, 394 of submandibular space, 117f anatomy of the airway, 315, 318
hoarseness causes in airway Eschmann stylet, 134, 135f, 164 background and equipment, 315
management, 398–399 Esmolol, 396 bronchus intermedius view, 317f
oropharyngeal soft tissue injury, 396–397 Esophageal bulb detector device, 45, 48f carina as viewed through flexible
patient-specific risk factors, of dental Esophageal intubation, CO2 in, 45 bronchoscope, 316f
injury, 398t Esophageal perforation indications, 315
pneumothorax, 399–400, 400f endotracheal intubation left lower lobe bronchus view, 318f
predisposing factors, 394 complication, 395–396 left mainstem bronchus view, 317f
prolonged tracheal intubation, Esophageal-Tracheal Combitube (ETC), 90, left upper lobe bronchus view, 317f
complications from, 400 199–203 procedure, 318–319
spinal cord injury, 396 advanced into esophagus, 201f right mainstem bronchus view, 316f
subcutaneous emphysema, 396f, 400f complications, 203 right upper lobe bronchus view, 316f
universal numbering system for adult concept, 199, 200f sedation and preparation, 318
dentition, 397f contraindications, 203 Fiberoptic incubating scope, 179f
vocal cord bowing, risk of tracheal cuffs inflated, 201f Fiberoptic stylet, 162, 164
intubation, 399f evidence, 199 Fiberoptic techniques
wrapping 8-0 suture around loose tooth, indications, 203 flexible fiberoptic bronchoscopes
398f inserting, 202f intubation, 177–189
Endotracheal tube (ETT) inserting into pharynx in cadaver rigid fiberoptic scopes and video
adjuncts to ETT, 334 specimen, 200f laryngoscopes, 191–197
advanced along wire/guide catheter, 174f practicality, 203 Flexible fiberoptic bronchoscopes (FOBs)
advancing into glottis, 143f, 147f procedure, 199, 203 intubation and esophago-
advancing into nasopharynx over FOB, 188f Esophagus tracheal combitube (ETC)
advancing through Williams airway into bougie placed into, 137f concept, 257
glottis, 149f ETC advanced into, 201f contraindications, 257
bevel of, 189f ESWL. See Extracorporeal Shock Wave ETC in place in cadaver specimen, 258f
confirming placement, 45–49, 46f, 47f, Lithotripsy (ESWL) evidence, 257
48f, 49f ETC. See Esophageal-Tracheal FOB inserted into larynx, with ETC in
cuff in trachea, balloting, 48f Combitube (ETC) place, 259f
extracting ILMA while grasping, 220f ETI. See Endotracheal tube indications, 257
in hypopharynx, 142f introducers (ETI) insertion of FOB into pharynx with
inserting, 222f Etomidate, 51t, 353 oropharyngeal cuff down, 258f
DESIGN SERVICES OF

412 INDEX
Flexible fiberoptic bronchoscopes (continued) glottis as seen through, 185f inserted over wire, 172f, 173f
practicality, 257 ILMA in conjunction with, 215 Guidelines for difficult airway
preparations, 257 indications, 182, 188 management, 87
procedure, 257 inserting Williams airway for Gum elastic bougie (GEB), 133–134
Flexible fiberoptic bronchoscopes (FOBs) intubation, 182f “Gutter,” transmucosal anesthetic injection
intubation through intubating insertion through nasal cavity, 187f in, 180f
laryngeal mask airway (ILMA) intubation, nasal approach for, 187f GVL. See GlideScope Video Laryngoscope
complications, 256 lidocaine nebulization for laryngeal and (GVL)
concept, 252 tracheal anesthesia, 181f Gyrus ACMI, 191
confirming ETT position by scope, 256f oral approach, 184f
contraindications, 256 oral ETT insertion over, 184f H
evidence, 252 placing Krause forceps in pyriform
FOB advanced through ILMA into recess, 180f Hand jet insufflators
glottis, 254f practicality, 182 device specification, 343–344
ILMA incadaver specimen, 253f preparation, 178, 182 examples of, 344f
ILMA in place, 255f superior laryngeal nerve block, 180f, 181f guidelines for using, 342–344
ILMA with FOB placed through it, 253f tracheal rings after entering larynx, 186f LFJV myths, 344
image from FOB, glottic opening, 254f transmucosal injection of anesthesia in ventilation guidelines, 344
indications, 256 gutter, 180f HB. See Hyoid bone (HB)
inserting ETT through ILMA, 255f FOB. See Fiberoptic bronchoscopy (FOB) Head-elevated laryngoscopic position
inserting FOB through ETT into airway, Fogarty embolectomy catheter, 328 (HELP), 371, 372f, 373f
255f Fractures Head size, pediatric, 291
practicality, 252 dislocation/cervical spine, difficult airway HEL. See Hyoepiglottic ligament (HEL)
preparation, 252 management in, 115, 122f HELP. See Head-elevated laryngoscopic
procedure, 252 facial, difficult airway management in, position (HELP)
Flexible fiberoptic bronchoscopes (FOBs) 115, 122f Hematoma, difficult airway management in,
intubation through laryngeal laryngeal, difficult airway management 118, 125–126f
mask airway (LMA) in, 115, 123f Hemifacial microsomia, 294t
complications, 248 mandibular, difficult airway management Hertz (Hz), 340
concept, 247 in, 115, 121f HFJV. See High-frequency jet
contraindications, 248 FRC. See Functional residual capacity ventilation (HFJV)
evidence, 247 (FRC) HFV. See High-frequency ventilation (HFV)
FOB advanced through the grill of LMA, Frova intubating stylet, 133, 135f High-frequency jet ventilation (HFJV), 334,
revealing glottis, 250f Functional residual capacity (FRC), 370, 340–348
FOB image from LMA revealing epiglottis, 250f 376, 379 anesthetic management, 345
FOB inserted through LMA into glottis, 248f characteristics of HFV modes and
FOB insertion into LMA after ventilation G conventional ventilation,
optimized, 249f 340–342, 341t
indications, 248 Gastric aspiration, LMA use and, 205 complications of LFJV and, 342, 343t
introduction of 6.0 ETT into LMA, 250f GEB. See Gum elastic bougie (GEB) connection to anesthesia circuit during
practicality, 247 GlideScope Cobalt laryngoscope, 306 the use of HFJV, 345f
preparation, 247 GlideScope Video Laryngoscope (GVL), 46f, in continuous positive airway pressure
procedure, 247 191, 196, 197t (CPAP) in one-lung
pushing ETT through LMA mask into blade sizes, 192f ventilation, 347, 348f
larynx, 249f view of glottis with, 192f differences and advantages, over
Flexible fiberoptic bronchoscopes (FOBs) Glossopharyngeal nerve, 57–58 LFJV, 340–342
intubation, 177–189. invasive intraoral approach, 58f elective transtracheal jet ventilation for
See also Nasal flexible fiberop- palatoglossal arch, 57f assistance with fiberoptic
tic bronchoscopes intubation; Glottic visualization, 62 bronchoscopy, 346
Orotracheal flexible fiberoptic Glottis ENT procedures, 346
bronchoscopes intubation advancing ETT into, 143f, 147f, 149f Extracorporeal Shock Wave Lithotripsy
anesthestizing glottis by transtracheal ILMA inflated to seal, 218f (ESWL), 347
lidocaine injection through jaw thrust facilitating visualization of, 165f flexible bronchoscopy and endotracheal
CTM, 181 lightwand-ETT approaching, 154f tube exchange, 347
atomziers to spray back of tongue and paraglossal straight blade technique to guidelines for, 344–346
pharynx, 180f view, 41 humidification, 345–346
carina as seen through, 186f as reflected in Skier blade mirror, 131f initial settings, 345
complications of oral and nasal as seen through FOB, 185f and low-frequency jet ventilation
intubation, 188 as seen through FOB after jaw thrust, 185f (LFJV), 340
concept, 177–178 view with GVL, 192f major airway reconstructive
contraindications, 186, 188 view with/without external laryngeal procedures, 346
equipment for nasal fiberoptic awake pressure, 40f monitoring adequacy of ventilation, 345
intubation, 179f using GlideScope Video Laryngoscope oxygen insufflation in sedation cases, 347
equipment for oral fiberoptic awake (GVL), 46f perioperative applications of, 346–348, 346t
intubation, 179f Glycopyrrolate, 53t, 55, 56 radiofrequency ablation of atrial
evidence, 178 Greater and lesser palatine nerves, 57 fibrillation, 347
fiberoptic intubating scope, 179f Guide catheter, 167 rigid bronchoscopy, 346
DESIGN SERVICES OF

INDEX 413
role of rate, inspiratory time, and driving ETT insertion with black line facing L
pressure, 344–345 cephalad, 222f
secretions movement from trachea toward ETT passing into trachea, 219f Laryngeal anesthesia, lidocaine nebulization
glottic opening during, 343f ETT placed through ILMA, 218f for, 181f
use of hand jet insufflators, guidelines evidence, 214–215 Laryngeal carcinoma, difficult airway
for, 342–344 grasping ETT as ILMA removed from management in, 115, 120f
High-frequency positive pressure ventilation mouth, 223f Laryngeal edema, postextubation, 355
(HFPPV), 340, 341t grasping ETT while extracting ILMA, 220f Laryngeal exposure, grades of, 63f
High-frequency ventilation (HFV) ILMA in correct position and ventilation Laryngeal injury, 115, 123f
characteristics of various modes and initiated, 221f Laryngeal inlet and epiglottis control, 6
conventional ventilation, indications, 223 Laryngeal Mask Airway (LMA), 87, 90,
340–342, 341t inflated to seal glottis, 218f 152, 225. See also Intubating
Hoarseness and vocal cord damage in airway insertion, 221f laryngeal mask airway (ILMA)
management, 398–399 intubation through, 239–242 advanced into pharynx, 209f
“Hockey stick” shape of, lighted stylet, 152 in place for ventilation, 217f Ambu AuraOnce, 204, 206f
Hunsaker Mon-Jet Ventilation Tube, 346 placement into pharynx, 217f complications, 212
Hurricane spray, 56 preparation, 215, 216f concept, 204
Hyoepiglottic ligament (HEL), 6, 10f procedure, 215–216 contraindications, 212
Hyoglossus muscle, 1 removal of, 219f, 220f and Esophageal-Tracheal Combitube
Hyoid bone (HB), 1, 2f removing LMA with push rod, 222f (ETC), 199
and thyroid cartilage, 9, 11f stabilizing ETT during LMA removal, 220f evidence, 204–206
Hypertrophic lingual tonsils, 1, 3f Intubation indications, 212
Hypertrophy of airway tissues, 118 blind, adjustment maneuvers for, 214t inflated cuff to create seal around
Hypopharynx, 156f, 191, 211f complications (acute and chronic), larynx, 210f
Hypotension, 355 395t. See also Endotracheal inserting, 208f, 210f
Hypoxia, 355 intubation complications intubation through, 239–242
risk of, 375–376 difficult, 62–67 lightwands assisted intubation through, 240
digital, 145, 147, 146–147f in obese patients, 205
I equipment, 36f pediatric airway, 306
with fiberoptic bronchoscope, 247 in place over larynx, 209f
IC. See Inspiratory capacity (IC) indications, 45, 47f practicality, 212
IID. See Inter-incisor distance (IID) “Intubation difficulty scale (IDS),” 66 preparation, 206
ILMA. See Intubating laryngeal mask Intubation through Laryngeal Mask Airway procedure, 206, 210, 212
airway (ILMA) (LMA) and intubating proseal, 207f
“Improved View Macintosh” blade, 29, 32f, 33t laryngeal mask airway (ILMA) single-use, 205f
IMV mode. See Intermittent mandatory complications, 241 sizes and inflation volumes, 208t
ventilation (IMV) mode concept, 239 sliding along hard palate, 211f
Induction sequence, 53t contraindications, 241 Supreme, 204, 207f
Inspiratory capacity (IC), 379 evidence, 239 unique (single-use), 205f
Inspiratory phase, 383 indications, 241 Laryngeal nerve block, superior, 180f, 181f
Inspiratory positive airway pressure (IPAP), 26 insertion of ETT/lightwand into Laryngeal tube (King LT and King LTS), 226f
Inter-incisor distance (IID), 65 LMA, 240f description, 225
assessment of, 66f lightwand/ETT advanced into airway, 241f as difficult airway device, 226
Intermittent apnea technique, 334–335 practicality, 240 emergency medical technicians
Intermittent mandatory ventilation (IMV) preparation for, 240 (EMTs), 226
mode, 386 procedure, 240 evidence, 225–226
Intraoral examination, in infant, 294 using ILMA and inserting larger ETT, 242f manikin/simulation studies, 226
Intravenous fentanyl, 396 IPAP. See Inspiratory positive airway in operating room, 226
Intravenous general anesthetic agents, 50, 51t pressure (IPAP) procedure, 226–227
Intravenous sedation, for awake Laryngoscopy, direct. See Direct
intubation, 55–56 J laryngoscopy (DL)
Introducer. See Bougies and airway stylets Jackson, Chevalier, 277, 309 Larynx
Intubating laryngeal mask airway (ILMA), congenital subglottic stenosis, 113f
214–223. See also Laryngeal K difficult airway management and, 109, 113f
Mask Airway (LMA) and epiglottis, 1, 6
adaptor attached to ETT and ventilation Ketamine, 50, 51t, 56, 353 ETT advanced along wire/guide catheter
confirmed, 222f Killian, Gustav, 309 into, 174f
adjusting maneuvers for blind intubation King LT airway, 225–227, 226f ETT placed over FOB into, 189f
through, 214t as difficult airway device, 226 of infant, 293f
complications, 223 emergency medical technicians lightwand-ETT in both sides of
concept, 214 (EMTs), 226 esophagus and, 156–157f
contraindications, 223 manikin/simulation, 226 LMA in place over, 209f
in correct position and ventilation in operating room, 226 operator and alternative views, 6
initiated, 221f “Kissing” tonsils, 296f palpating CTM while grasping, 267f
efficacy in obese patients, 215 Klippel-Feil syndrome, cervical spine position, for premature infant, full term
ETT in place and ventilation anomaly in, 113f infant, and adult, 291, 292f
re-initiated, 221f Krause forceps, 180f tip of optical stylet-ETT placed into, 163f
DESIGN SERVICES OF

414 INDEX
Laser airway surgery barotrauma, 342 Miller blades, for laryngoscopes, 29, 30f,
adjuncts to endotracheal tubes, 334 common characteristics with HFJV, 340 31f, 33t
bronchoscopy, 334 complication and HFJV, 342, 343t Minute ventilation (MV), 341
concept, 333 differences and advantages of HFJV, Mirror blades and prism blades
endotracheal tubes, 333–334 340–342 Airtraq device, 127–129, 128f, 132f
fire prevention, 335 Ludwig angina, difficult airway management complications, 130
intermittent apnea, 334–335 in, 115, 117f concept, 127–129
intubation technique, 333 contraindications, 130
jet ventilation, 334 M evidence, 129
Mallinckrodt Laser-Flex double cuff tube indications, 130
with methylene blue, 337f Macintosh blade, 41, 127, 311 laryngoscopy with prism on 3 Mac
Mallinckrodt Laser-Flex endotracheal laryngoscope, 29, 30f, 31f, 33t blade, 131f
tube, cuffless, 337f Macroglossia, 294t practicality, 130
Mallinckrodt Laser-Flex endotracheal with Beckwith–Wiedemann syndrome, 304f preparation for direct laryngoscopy, 129
tube with double cuff, 336f Mallampati classification, 62–65 prism for 3 Mac blade, 128f
Mallinckrodt Laser-Flex tube with Mallampati score, 62 prism for 3 Mac blade mounted, 128f
aluminum foil, 338f Mallampati Test (MP), 70 procedure, 130, 130–132
pilot cuffs of Mallinckrodt Laser-Flex Malleable Eschmann introducer, 133 Siker blade, 127f, 130–131f
tube filled with methylene Mallinckrodt Laser-Flex endotracheal MMS. See Modified Mallampati
blue, 338f tubes, 333 score (MMS)
spontaneous breathing technique, 335 with aluminum foil covering PVC adapter Modified Mallampati score (MMS),
view of larynx and vocal cord with CO2 and circuit, 338f 62–65, 64f
laser, 336f cuffless, 337f Morbid obesity and bariatric surgery
view of larynx with Mallinckrodt Laser-Flex with double cuff, 336f Bainton laryngoscope blade, 372f
endotracheal tube, 335f with methylene blue, 337f HELP position, 372f, 373f
view of operating field draped in pilot cuffs of, filled with methylene increased neck circumference and
saline-soaked towels, 339f blue, 338f Mallampati class three
Lasertubus, 333 view of larynx with, 335f airway, 372f
Levitan (First Pass Success or FPS) Optical Mandibular fracture, difficult airway multichambered inflation device used for
Stylet, 161 management in, 115, 121f positioning patient, 374f
LFJV. See Low-frequency jet ventilation (LFJV) Mandibular size, difficult airway supine position with excessive anterior
Lidocaine, 52, 53t, 56, 59, 396 management and, 109, 111f neck adipose tissue, 373f
Lighted stylet. See Lightwands Manual inline stabilization (MILS), of Troop elevation pillow, 373f
Lightwands cervical spine, 65 Morph function, 82
assisted intubation through LMA, 240 Mask ventilation, 13–20 Morphine, 51t, 55
complications, 159 complications, 20 Mouth
concept, 151 concept, 13 difficult airway management and, 109, 110f
contraindications, 159 contraindications, 20 and tongue anatomy, 1–8
ETT loaded, locked into position, 158f difficult, 14, 18f, 19f, 61–62 Murphy eye, 167, 239, 301
evidence, 151–152 EMA-T device, 14, 19f Muscle relaxants, for airway
indications, 158 evidence, 13–14 management, 50, 51t
inserting ETT into pharynx, 158f examples of face masks, 15f Muscle tone and “peardrop” phenomenon, 1
inserting of ETT/lightwand into face mask application, 18f
LMA, 240f facial hair in, 109, 112f N
insertion of lightwand-ETT, 154f, 155f indications, 14
lightwand advanced into of nasopharyngeal airways, 15f, 16f, 17f Nasal cavity, insertion of FOB through, 187f
hypopharynx, 156f one-person placing mask, 19f Nasal fiberoptic awake intubation,
lightwand-ETT advanced into airway, oropharyngeal airways assisting with, 15f equipment for, 179f
155f, 241f placing nasopharyngeal airway, 16f Nasal flexible fiberoptic bronchoscopes
lightwand-ETT approaching glottis, 154f placing oropharyngeal airway, 16f, 16f, 17f intubation, 186, 188
lightwand-ETT in both sides of esophagus practicality, 14 bevel of ETT on aryepiglottic fold during
and larynx, 156–157f preparation, 14 tube insertion, 189f
pediatric lighted stylet, 304–305 two-person mask technique, 18f ETT advancement into nasopharynx over
practicality, 158 using “lower lip” facemask placement, 19f FOB, 188f
preparation, 152 McAslan, Crawford, 107 ETT placed over FOB into larynx, 189f
procedure, 152, 158, 240 McCoy laryngoscope blade, 29, 33t inserting FOB through nasal cavity, 187f
removal of stylet from ETT, 159f Melker Emergency Cricothyrotomy Kit, nasal approach for FOB intubation, 187f
rocking motion with lightwand, 157f 273, 274 Nasal mask
using ILMA and inserting larger Mercury Medical, 191, 214 advantages and disadvantages, 25t
ETT, 242f Merocel Laser-Guard ET protector, 334 example of, 24f
Limit variable, 383 Metal endotracheal tubes, 333 patient wearing, 24f
Lingual tonsil, 1 Methemoglobin, 56 Nasal pillows
LMA. See Laryngeal Mask Airway (LMA) Methemoglobinemia, causes of, 56 advantages and disadvantages, 25t
Local anesthetics, for awake intubations, 56 Micrognathia in patient with Pierre Robin patient demonstrating, 24f
Lorazepam, 55 sequence, 305f Nasal turbinates, difficult airway
Low-frequency jet ventilation (LFJV) Midazolam, 51t, 55, 56, 353 management and, 109, 112f
aspiration protection in open systems, 342 Midface hypoplasia, 294t, 295f Nasopharyngeal airway
DESIGN SERVICES OF

INDEX 415
array of, 15f aspiration risks, 375, 376–377 Oropharyngeal soft tissue injury, during
improper size of, 17f difficult airway, 377 endotracheal intubation,
placement of, 16f enlarged breast tissue, 375 396–397
Nasopharyngeal carcinoma, difficult airway hypoxia risks, 375–376 Oropharynx, 64, 154f
management in, 115, 120f pregnancy-related anatomic and Orotracheal flexible fiberoptic
Nasopharynx, neuroanatomy of, 56f physiologic changes, bronchoscopes intubation
Nasotracheal approach, fiberoptic 375–376, 376f after entering larynx, as seen through
bronchoscopes and, 178 weight gain, 375 FOB, 186f
Nasotracheal intubation, 53t Obstructive sleep apnea (OSA), 81 carina, as seen through FOB, 186f
Neck additional airway management strategies improved view of glottis, as seen through
with congenital malformations, difficult for, 368t FOB, 185f
airway management in, 109, in adults, 361–369, 363–367f insertion for oral intubation, 183f
111f, 114, 114f consequences in pediatric jaw thrust during insertion of FOB, 183f
edema of, difficult airway management population, 362t oral ETT insertion over FOB, 184f
in, 123f in pediatric patient, 361 oral FOB approach, 184f
extension, 294t, 295 perioperative issues and strategies in poor view of glottis as seen through
Neodymium:yttrium-aluminum-garnet pediatric patients, 362t FOB, 185f
(Nd:YAG) laser, 334 perioperative risks, 368t Orotracheal FOB intubation, 182, 182–186f
Neoplasms, difficult airway management in, predisposing factors, 368t OSA. See Obstructive sleep apnea (OSA)
115, 119–120f recommendations for perioperative Ovassapian airway, 182
Neuromuscular blocking agents, management with, 368t
nondepolarizing, 50, 51t Olfactory nerves, 57f P
Neustein blade, 127 OLV. See One-lung ventilation (OLV)
NIPPV. See Noninvasive positive pressure One-lung ventilation (OLV), 321, 328 Palatine nerves, greater and lesser, 57
ventilation (NIPPV) Operating room (OR) Palatoglossal arch, 57f
Nishikawa laryngoscope blade, 29, 33f, 33t airway management in, 91t Pancuronium, 51t
N-Methyl-D-aspartic acid antagonist, 56 capnography in, 47f “Paraglossal straight blade” technique, 41, 42f
Nondepolarizing neuromuscular blocker, inserting LMA in elective situation in, 211f Paraglottic laryngoscopy, 42f
50, 51t King LT in, 226 Pathology, difficult airway management in, 114
Noninvasive positive pressure ventilation Laryngeal mask airway (LMA) in, 204 Patient care with surgical airway, 403–407
(NIPPV) optical stylets in, 162 airway emergencies in, 407
advantages and disadvantages of patient percutaneous tracheostomy in, 283 bleeding, 407
interfaces in, 25t retrograde intubation in, 167 cuffed tubes versus noncuffed
bilevel positive pressure ventilation tracheostomy in, 277 tubes, 404, 406f
device, 21f Opioids, 52, 55–56 potential complications, 406
clinical indications for, 23t Optical stylets, 161–166. See also Shikani tracheostomy, oxygenation and
complications, 26 optical stylet ventilation in patient with,
concept, 21 complications, 166 403, 404f
contraindications, 26 concept, 161 tracheotomy, oxygenation and ventilation
evidence, 21–26 contraindications, 166 in patient with, 403, 405f
example of nasal mask, 24f evidence, 162, 164 Patil Emergency Cricothyrotomy Catheter
example of oronasal mask, 23f indications, 166 set, 273
improperly fitted oronasal mask, 27f intubation through LMA and ILMA with, PBlade, 191
indications, 26 239–242 PCT. See Percutaneous tracheostomy (PCT)
oronasal mask with head straps, 25f practicality, 166 “Peardrop” phenomenon, 1, 5f
patient demonstrating nasal pillows, 24f preparation, 164 Pediatric airway anatomy and approach
patient wearing nasal mask, 24f types of stylets, 161 airway edema effects on resistance in
patient wearing oronasal mask, 23f Optimal external laryngeal manipulation, 37 infant and adult, 293f
in patient with acute respiratory failure, 22f OR. See Operating room (OR) anatomic pathology predicting difficult
practicality, 26 Oral cavity, difficult airway management pediatric airway, 294t
preparation, 26 and, 109, 113f, 115, 123–124f Apert syndrome, 295f
procedure, 26 Oral fiberoptic awake intubation, equipment Crouzon syndrome, 295f
selection criteria for, 23t for, 179f developmental anatomy, 291–293
Norton laser endotracheal tubes, 334 Oral intubation developmental physiology, 293–294
Nose, dilation of, 141f FOB, jaw thrust during, 183f facial asymmetry, 295f
insertion of FOB for, 183f fiberscopes with outer diameters for, 178
O Oronasal mask large occiput in neonate and infant places
advantages and disadvantages, 25t the neck in natural flexion, 292f
Obese patients, 66. See also Morbid obesity example of, 23f larynx of infant, 293f
and bariatric surgery with head straps, 25f lateral view of infant with Pierre Robin
efficacy of ILMA in, 215 improperly fitted, 27f Sequence, 296f
Laryngeal mask airway (LMA), 205 patient wearing, 23f, 25f pediatric airway examination, 294–296
sniffing position in direct Oropharyngeal airway position of larynx for premature infant,
laryngoscopy, 39f array of, 15f full term infant, and adult,
Obstetrics improper size and placement of, 17f 291, 292f
airway edema, 375 placement of, 16f retrograde intubation, 167
anesthesia for labor and delivery, 377f Oropharyngeal assessment, 62, 64f tonsillar grading, 296f
DESIGN SERVICES OF

416 INDEX
Pediatric endotracheal tube round “stop” on white guide to prevent- synchronized intermittent mandatory
position of, 301t ing insertion of dilator, 287f ventilation (SIMV), 386
size of, 301t white guide in placing over the wire after ventilator control principles, 382–383
Pediatric laryngoscope blade choice, 300t removal of dilator, 288f PPV. See Positive pressure ventilation (PPV)
Pediatric obstructive sleep apnea (OSA), white style guide and dilator, placing over Pregnancy-related anatomic and physiologic
361, 362t the wire, 287f changes, 375–376
Pediatric patients “Perfect storm,” 52 Preoxygenation, in critically ill patients, 353
optical stylets in, 164 Peritonsillar abscess, difficult airway Pressure Assist. See Assisted Mechanical
Pediatrics, adjuncts to direct laryngoscopy management and, 115, 119f Ventilation (AMV)
in, 303–307 Pharmacology for airway Pressure support ventilation (PSV), 386
Air-Q LMA with classic LMA facilitating management, 50–53 Prism blades and mirror blades. See Mirror
LMA-guided flexible fiberoptic Pharynx blades and prism blades
intubation, 307f difficult airway management of, 124f Propofol, 50, 51t, 353
macroglossia with Beckwith–Wiedemann ETC inserted into, 200f Proseal LMA, 204, 205–206, 207f
syndrome, 304f laryngeal mask airway advanced into, 209f PSV. See Pressure support ventilation (PSV)
micrognathia with Pierre Robin placement of ILMA into, 217f
sequence, 305f wire insertion through needle, retrograde
Q
modified nasal airway for pediatric into, 170f
nasal flexible fiberoptic Phase variables, 383–386 QuickTrach, 273
bronchoscopy, 305f Phenylephrine, 53t
reconstructing pilot balloon after LMA- Phillips blade, 29, 30f, 33t, 42f, 300 R
guided fiberoptic intubation Pierre Robin Sequence
with cuffed ETT, 306f lateral view of infant with, 296f Radiography and endoscopy, 296
retromolar technique of pediatric micrognathia in patient with, 305f Rapid sequence intubation (RSI), 13, 52, 61,
laryngoscopy, 304f Plateau pressure, 390 67, 91, 359
Pediatrics, direct laryngoscopy in, 298–302 Plexiglas prism, 127 elective intubation and, 53t
comparing new Microcuff pediatric ETT Pneumothorax Recurrent laryngeal nerve, 59–60
to routine pediatric ETT, 302f endotracheal intubation complication, transtracheal nerve block, 59f
equipment for pediatric airway 399–400 Red rubber tubes, 333
management, 299f “Pocket Scope,” 161 Refractory hypoxemia, treating, 392–393
MRI of infant, 301f Point clouds, 81 Registration process, 81, 82f
pediatric endotracheal tube, position Polhemus FAST SCAN, 81, 81f Relaxants, muscle, for airway
of, 301t Polygonal mesh, 81 management, 50, 51t
pediatric endotracheal tube, size of, 301t Polyvinyl chloride (PVC) tubes, 333 Remifentanil, 55
pediatric laryngoscope blade choice, 300t “Poor Man’s Cricothyrotomy,” 267f Rendering process, 81
positioning for seated direct laryngoscopy Positive pressure ventilation (PPV) Retraction blades for direct laryngoscopy,
in neonate, 299f airway pressure release ventilation 29–34
subglottic stenosis after prolonged (APRV), 387–388, 388f Bizzarri-Giuffrida laryngoscope blade, 32f
neonatal intubation, 300f assist/control (A/C) mode, 386 Choi laryngoscope blade, 32f, 33t
warning for using succinylcholine in clinical scenarios 1 (obese woman Macintosh blade with tip in vallecula,
pediatric intubations, 299f with surgical complication), 31f, 33t
Pentax AWS, 191, 196, 197t 388–391 Macintosh laryngoscope blade, 30f, 32f, 33t
and disposable clear blade, 193f clinical scenarios 2 (elderly veteran with Miller and Phillips laryngoscope blades,
with ETT, 193f pneumonia), 391–393 30f, 33t
Percutaneous tracheostomy (PCT) continuous mandatory ventilation Miller blade lifting epiglottis, 31f
after transverse skin incision, blunt (CMV), 386 Nishikawa laryngoscope blade, 29, 33f, 33t
dissection is carried out down continuous positive airway pressure selected, 33t
to trachea level, 285f (CPAP), 387 Retrognathia, 294t, 296f
bronchoscopic guidance of PCT during control waveforms, 383f Retrograde intubation (RI)
training in anatomy lab, 286f intermittent mandatory ventilation complications, 176
bronchoscopic view of tracheostomy tube (IMV), 386 components of Cook RI Kit, 168f
insertion and dilator over the lung volumes and capacities in average concept, 167
wire, 288f adult, 380f contraindications, 175
complications, 289 modes of ventilation, 386–388 ETT advanced along wire/guide catheter,
concept, 283 phase variables, 383–385, 385f into larynx, 174f
contraindications, 289 pressure support ventilation (PSV), 386 ETT inverting over guide catheter, 173f
equipment for, 284f pressure versus volume for evidence, 167
evidence, 283–284 inspiration, 382f guide catheter inserted over wire, 172f
indications, 289 relationship between pressure, flow, indications, 170
needle placement in trachea, 285f resistance, and elastance, insertion of needle at cricotracheal
placing guidewire through needle into tra- 381, 382 ligament, 175f
chea of cadaver specimen, 286f scientific underpinnings of, 379–382 needle insertion in cricothyroid
practicality, 289 single alveolus model for respiratory membrane, 168f, 169f
preparation, 284 mechanics, 381f oral procedure for, 169–170
procedure, 284–285 spirometry, 379 practicality, 170
removal of dilator, guide catheter, and square pressure wave and square flow preparation, 168
guidewire, 288f wave comparison, 390f procedure, 169–170
DESIGN SERVICES OF

INDEX 417
removing guide catheter after ETT pharmacology for airway Supraglottic airway device (SGA)
advancing to CTM, 176f management, 50–53 categorization of, 225
removing wire and guide catheter, 175f retraction blades for direct Cobra Perilaryngeal Airway (PLA),
wire grasped with hemostat and retrieved laryngoscopy, 29–34 227–228, 227f
from mouth, 171f RSI. See Rapid sequence intubation (RSI) complications, 229
wire inserted into distal lumen of ETT, 174f concept, 225
wire insertion through thin-walled S contraindications, 229
needle, retrograde into indications, 229
pharynx, 170f Saline-filled cuffs, on endotracheal tubes, 334 laryngeal tube (King LT and King LTS),
Retrograde intubation (RI) and flexible Samsoon and Young modification of 225–227, 226f
fiberoptic bronchoscope Mallampati oropharyngeal practicality, 229
(FOB) intubation assessment, 62, 64f Streamlined Liner of the Pharyngeal
advancing FOB distally in trachea, 246f Seldinger technique, 273 Airway (SLIPA), 228–229, 228f
complications, 243 Sellickmaneuver, 377 Supraglottic cancer, difficult airway
concept, 243 Sensascope, 161 management in, 115, 119f
contraindications, 243 Sevoflurane, 50 Surgical airway, patient care with. See
evidence, 243 SGA. See Supraglottic airway device (SGA) Patient care with surgical
FOB advanced over wire, 245f Sheridan Laser-Trach endotracheal tubes, 334 airway
FOB tip abuts the CTM, 245f Shikani optical stylet, 161, 162f, 305 Synchronized intermittent mandatory
indications, 243 with ETT advanced to glottis, 163f ventilation (SIMV), 386
inserting RI wire into suction channel of with ETT placed in mouth, 164f
FOB, 244f with ETT placed into larynx, 163f T
practicality, 243 guiding the tip into glottis, 165f
preparation, 243 insertion of, 162f Teleflex Medical, 321
procedure, 243 jaw thrust facilitating visualization of Temporomandibular joint (TMJ), 303, 304
retrieving wire from mouth, 244f glottis, 165f Tetracaine, 56
Retropharyngeal abscess, difficult airway removal of, 165f 3M 425 tape, 334
management in, 115, 118f Siker blade, 33t, 127, 127f Thyrohyoid membrane, 6
Rheumatoid arthritis in cervical spine, 125f grade 2 view of glottis as reflected in Thyroid, difficult airway management in, 126f
RI. See Retrograde intubation (RI) mirror, 131f Thyromental distance (TMD), 65–66, 70, 152
Rigid bronchoscopy insertion into mouth, 130f assessment of, 66f
bronchoscope, 309, 310f preparation for direct laryngoscopy TMD. See Thyromental distance (TMD)
high-frequency jet ventilation and, 346 with, 129 TMJ. See Temporomandibular joint (TMJ)
history, 309 procedure for direct laryngoscopy, 130 Tongue
indications for, 311t Silicone rubber tubes, 333 anatomy, 1, 291
insertion technique, 309, 311, 312f, 313f Simulation, in airway management training, enlarged in Down’s syndrome, 113f
for laser surgery, 334 96–101 enlargement of, in amyloidosis, 126f
patient selection, 309 SIMV. See Synchronized intermittent large, 109, 110f
ventilation, 311–312 mandatory ventilation (SIMV) Tonsillar grading, 296f
Rigid fiberoptic scopes and video Single-lumen tube, with incorporated BB, 328 Total intravenous anesthesia (TIVA), inter-
laryngoscopes, 191–197 SLIPA. See Streamlined Liner of the mittent apnea with, 333, 334
affordibility, 197 Pharyngeal Airway (SLIPA) Total lung capacity (TLC), 379
Bullard laryngoscope, 194f, 197t Smiths Medical, 321 Tracheal anesthesia, lidocaine nebulization
C-MAC Storz, 191, 194f, 196, 197t Sodium thiopental, 50, 51t for, 181f
complexity, 197 Sphenopalatine ganglion, 57, 57f Tracheobronchial rupture
complications, 197 Spinal cord injury, during endotracheal endotracheal intubation complication, 399
concept, 191 intubation, 396 Tracheoesophageal fistula, 395t, 400
contraindications, 197 Spirometry process, 379 Tracheomalacia, 395t, 400
evidence, 196 S-shaped laryngoscopes, 29, 33f Tracheoscopic Ventilation Tube (TVT), 161
indications, 197 “STOP MAID,” 35–36 Tracheostomy, 403, 404f. See also Percutaneous
overview, 197t Storz video laryngoscope, 306 tracheostomy (PCT)
Pentax AWS, 191, 193f, 196, 197t Straight blades, for direct laryngoscopy, 38, complications, 278
practicality, 197 41, 42–43 concept, 277
preparation for GVL, 192f, 196 Streamlined Liner of the Pharyngeal Airway contraindications, 278
procedure for GVL, 192f, 196 (SLIPA), 225, 228f dissecting subcutaneous tissue and pla-
size of GVL blade, 192f description, 228 tysma using electrocautery, 280f
Upsherscope, 191, 195f, 196 evidence, 228–229 evidence, 277
view of glottis with GVL, 192f procedure, 229 indications, 278
WuScope, 191, 195f Stylohyoid ligament (SHL), 1, 2f infiltrating local anesthetic solution under
“Robin Hood hat,” 6, 9f Subcutaneous emphysema, 395 the skin, 279f
Rocuronium, 50, 51t and pneumothorax, 400f insufflating tracheal cuff and connecting
Routine airway management in supraclavicular area, 396f tracheostomy to ventilator, 281f
anatomy of direct laryngoscopy Subglottic stenosis, 294t landmarks, 279f
(DL), 1–11 Subglottis, 293 making transverse incision with thyroid
direct laryngoscopy, 35–43 Succinylcholine, 50, 51t, 298, 353 cartilage, 279f
endotracheal tube placement, 45–49 adverse responses and contraindications, 52t oxygenation and ventilation in patient
mask ventilation, 13–20 Superior laryngeal nerve, 58–59 with, 403
DESIGN SERVICES OF

418 INDEX
Tracheostomy (continued) Transtracheal jet ventilation (TTJV) US imaging. See Ultrasound (US) imaging
practicality, 278 and flexible fiberoptic
preparation, 277 bronchoscope (FOB) V
procedure, 278 intubation
separating strap muscles by making advancement of ETT over FOB into Vagus nerve
vertical incision, 280f trachea, 262f recurrent laryngeal nerve, 59–60
stay sutures placement, 281f complications, 260 superior laryngeal nerve, 58–59
using tracheal spreader to dilating concept, 260 VBM Manujet III, 231
trachea, 281f contraindications, 260 Vecuronium, 50, 51t
Tracheotomy, 403, 405f evidence, 260 Ventilator control principles, 382–383
cuffed tracheotomy tubes, 406f indications, 260 Venture copper foil tape, 334
oxygenation and ventilation in patient insertion of FOB into larynx, 261f Venturi jet ventilation, 334
with, 403 ongoing TTJV and nasal airway in Video laryngoscopes, 191. See also Rigid
Trachlight device, 151, 152 place, 262f fiberoptic scopes and video
ETT loaded, locked into position, 158f ongoing TTJV simulated in cadaver laryngoscopes
insertion of ETT into pharynx, 158f specimen, 261f Viral laryngotracheobronchitis, difficult
procedure for, 152, 158, 158f practicality, 260 airway management in, 124f
Training in airway management preparation, 260 Vital capacity (VC), 379
accelerating success rate and patient procedure, 260 Vivid 900 scanner, 81, 81f
safety, 104–105t Transtracheal lidocaine injection, 181f Volume Assist. See Assisted Mechanical
airway and mask technique, 107 Trauma, difficult airway management in, Ventilation (AMV)
bag-mask-ventilation (BMV), 107 115, 121–123f
difficult airway simulation, 96–101 Trigeminal nerve W
“feel of the bag,” 107 anterior ethmoid nerve, 56
flexion-facilitation of DL, 105, 107 greater and lesser palatine nerves, 57 Whelan–Callicott position, 371
improving reliability of glottic Trigger variable, 383 Williams airway
exposure, 106t Troop elevation pillow, 371, 373f advancing EET into glottis, 149f
laryngeal mask airway, placing, 101f Truview EVO2, 306 inserted for FOB intubation, 182, 182f
learning curve intubation, 104f TTJV. See Transtracheal jet ventilation placement in oropharynx in cadaver
monitors screen and computer simulation (TTJV) specimen, 148f
control, 100–101f TVT. See Tracheoscopic Ventilation Tube preparation for blind intubation
outline of simulation course, 98t (TVT) through, 147
sample scenario, 98–100t Winter Institute for Simulation, Education,
specific training program concepts and U and Research (WISER), 97
techniques, 105 Wire-guided cricothyrotomy
“Standard Induction of GA” selection in Ultrasonography, 45 advancing dilator into airway, 276f
ABC window, 101f Ultrasound (US) imaging complications, 274
at WISER, 97 of bedside airway assessment, 77–80 concept, 273
Transtracheal jet ventilation (TTJV) midsagittal submandibular sonography, 78f contraindications, 274
anesthesia machine adaptor, 232f sagittal scan, 79f, 80f enlarging CTM with scalpel, 275f
attaching syringe to catheter, 234f sonogram showing cricoid cartilage and evidence, 273
attaching TTJV with Luer-lock, 235f tracheal cartilages, 80f indications, 274
complications, 236 standoff gel pad, 78f Melker cricothyrotomy kit
concept, 231 suprahyoid region, 78f components, 274f
contraindications, 236 thyroid cartilage and vocal cords, needle puncture through CTM, 275f
cricothyroid membrane in cadaver transverse scan of, 79f practicality, 274
specimen, 234f thyroid gland and tracheal cartilage, preparation, 273
evidence, 231, 233 transverse scan of, 80f procedure, 274
holding hub of catheter until airway is transverse submandibular scan with the removing dilator with wire, 276f
established, 235f standoff pad, 78f threading tracheal tube and dilator over
indications, 236 Unconscious patients wire, 275f
palpating the cricothyroid effective application of face mask, 18f Wire-guided endobronchial blocker, 328
membrane, 233f mask ventilation in, 13–20 Wisconsin blade, 29, 33t
practicality, 235–236 Univent tube placement, 329, 331f WuScope, 191, 195f
preparation, 233 loading, 330f
procedure, 233, 235 in mainstem bronchus, 331f X
puncture of cricothyroid membrane, in right mainstem bronchus, 331f
234f, 236f University of Pittsburgh Medical Center Xomed Laser-Shield I endotracheal
regulator of pressure and hand valve (UPMC), 97, 103 tubes, 334
on–off, 232f Upper lip bite test (ULBT), 66–67 Xomed Laser-Shield II endotracheal
transtracheal needle, 232f Upsherscope, 191, 195f, 196 tubes, 334
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Orebaugh_FM.

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© 2012 by LIPPINCOTT WILLIAMS & WILKINS, a WOLTERS KLUWER business

Library of Congress Cataloging-in-Publication Data

First Edition ©2007 by Lippincott Williams & Wilkins

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We dedicate this atlas to the anesthesiology residents, anesthesiologists and other

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Ali R Abdullah, MBChB Franklyn Cladis MD

Mark Backeris, DO Ivan Colaizzi, MD

Joshua Baisden, MD Christopher W. Connor, MD, PhD

Ryan D. Ball, MD Daniel Cormican, MD

Shawn T. Beaman, MD David Crippen, MD, FCCM

Brian Blasiole, MD, PhD James Dargin, MD

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Lillian L. Emlet, MD, MS, FACEP Arun L. Jayaraman, MD, PhD

Theresa Gelzinis, MD Tara Knizner, MD

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Stephen M. McHugh, MD Katherin A. Peperzak, MD

William R. McIvor, MD Paul E. Phrampus, MD

Scott K. Muir, DO Max E. Rohrbaugh, MD

Adam Munson-Young, MD Ryan C. Romeo, MD

Andrew Murray MB ChB Tetsuro Sakai, MD, PhD

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Anthony Silipo, DO PGY-4 Samuel A. Tisherman, MD

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I n this, the second edition of the atlas, a number of

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M y aim in creating this book is to assist those learning

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W e greatly acknowledge the help of Dr. Branton

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Contributors List iv 12 Decision Making in Difficult Airway

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PART VII 38 Tracheostomy . . . . . . . . . . . . . . . . . . . . 277

Fiberoptic Techniques . . . . . . . . . . . . . 177 39 Percutaneous Tracheostomy . . . . . . . . . . . . 283

23 Flexible Fiberoptic Bronchoscope

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PART XV PART XVI

53 Obstetrics . . . . . . . . . . . . . . . . . . . . . . 375 Index 408

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Anatomy of Direct Laryngoscopy 1 cn

James Snyder and Steve Orebaugh

ORIENTATION The Tongue is a Dome of Muscle

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Genioglossus muscle Geniohyoid muscle

Mylohyoid muscle Hyoglossus muscle

Digastric muscle Geniohyoid

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FIG U RE 1-5 X-ray laryngoscopy: normal vs. the

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F I GUR E 1 -6 Laryngeal skeleton: Lateral X-ray and

Lateral thyrohyoid Pharyngeal Level of upper

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Cuneiform tubercle Rima glottidis Posterior cartilages

Larngeal ventrical Glottic rim