Airway Management

Airway Management 19 CHAPTER
KEYCONCEPTS
1 Improper face mask technique can result in postoperative hoarseness and increases
continued deflation of the anesthesia the risk of accidental extubation.
reservoir bag when the adjustable 6 Unrecognized esophageal intubation can
pressure-limiting valve is closed, usually produce catastrophic results. Prevention of this
indicating a substantial leak around the complication depends on direct visualization of
mask. In contrast, the generation of high the tip of the TT passing through the vocal
breathing circuit pressures with minimal cords, careful auscultation for the presence of
chest movement and breath sounds implies bilateral breath sounds and the absence of
an obstructed airway or obstructed tubing. gastric gurgling
2 The laryngeal mask airway partially while ventilating through the TT,
protects the larynx from pharyngeal analysis of exhaled gas for the presence
secretions, but not gastric regurgitation. of CO2 (the most reliable automated
3 After insertion of a tracheal tube (TT ), the cuff method), chest radiography, or use of
is inflated with the least amount of air fiberoptic bronchoscopy.
necessary to create a seal during positive 7 Clues to the diagnosis of bronchial
pressure ventilation to minimize the pressure intubation include unilateral breath sounds,
transmitted to the tracheal mucosa. unexpected hypoxia with pulse oximetry
(unreliable with high inspired oxygen
4 Although the persistent detection of CO2
concentrations), inability to palpate the TT
by a capnograph is the best confirmation
of tracheal placement of a TT, it cannot cuff in the sternal notch during cuff inflation,
exclude bronchial intubation. The earliest and decreased breathing bag compliance
evidence of bronchial intubation often is (high peak inspiratory pressures).
an increase in peak inspiratory pressure. 8 The large negative intrathoracic pressures
5 After intubation, the cuff of a TT should generated by a struggling patient in
not be felt above the level of the cricoid laryngospasm can result in the development
cartilage, because a prolonged of negative-pressure pulmonary edema
intralaryngeal location may result in even in healthy patients.
Expert airway management is an essential skill in presents various management techniques: and
anesthetic practice. This chapter reviews the discusses complications of laryngoscopy, intubation,
anatomy of the upper respiratory tract: describes the and extubation. Patient safety depends on a
necessary equipment for successful management, thorough understanding of each of these topics.
309
310 SECTION III Anesthetic Management
The epiglottis prevents aspiration by covering the glottis the

ANATOMY opening of the larynx during swallowing. The larynx is a
The upper airway consists of the pharynx, nose,
cartilaginous skeleton held together by ligaments and
mouth, larynx, trachea, and mainstem bronchi. The
muscle. The larynx is composed of nine cartilages ( Figure
mouth and pharynx are also a part of the upper
19–2): thyroid, cricoid, epiglottic, and (in pairs) arytenoid,
gastrointestinal tract. The laryngeal structures in part
cornicu-late, and cuneiform. The thyroid cartilage shields the
serve to prevent aspiration into the trachea.
There are two openings to the human airway: the nose, conus elasticus, which forms the vocal cords.
which leads to the nasopharynx, and the mouth, which leads

The sensory supply to the upper airway is derived
to the oropharynx. These passages are separated anteriorly
from the cranial nerves ( Figure 19–3). The mucous
by the palate, but they join posteriorly in the pharynx (
membranes of the nose are innervated by the
Figure 19–1). The pharynx is a Ushaped fibromuscular
ophthalmic division (V1) of the trigeminal nerve
structure that extends from the base of the skull to the cricoid
anteriorly (anterior ethmoidal nerve) and by the maxillary
cartilage at the entrance to the esophagus. It opens
division (V2) posteriorly (sphenopalatine nerves). The
anteriorly into the nasal cavity, the mouth, the larynx, and
palatine nerves provide sensory fibers from the
the nasopharynx, oropharynx, and laryngopharynx,
trigeminal nerve (V) to the superior and inferior surfaces
respectively. The nasopharynx is separated from the
of the hard and soft palate. The olfactory nerve (cranial
oropharynx by an imaginary plane that extends posteriorly.
nerve I) innervates the nasal mucosa to provide the
At the base of the tongue, the epiglottis functionally
sense of smell. The lingual nerve (a branch of the
separates the oropharynx from the laryngopharynx (or
mandibular division [V3] of the trigeminal nerve) and the
hypopharynx).
glossopharyngeal nerve (the ninth cranial nerve)
provide general sensation to the anterior two thirds and
posterior one third of the tongue, respectively. Branches
of the facial nerve (VII) and glossopharyngeal nerve
Hard palate provide the sensation of taste to those areas,
respectively. The glossopharyngeal nerve also
Soft palate innervates the roof of the pharynx, the tonsils, and the
undersurface of the soft palate. The vagus nerve (the
tenth cranial nerve) provides sensation to the airway
below the epiglottis. The superior laryngeal branch of
Nasopharynx
the vagus divides into an external (motor) nerve and an
Tongue internal (sensory) laryngeal nerve that provide sensory
Oropharynx supply to the larynx between the epiglottis and the vocal
cords. Another branch of the vagus, the recurrent
laryngeal nerve, innervates the larynx below the vocal
Hypopharynx cords and the trachea.
The muscles of the larynx are innervated by the
recurrent laryngeal nerve, with the exception of the
Epiglottis
cricothyroid muscle, which is innervated by the external
(motor) laryngeal nerve, a branch of the superior laryngeal
Vocal cords nerve. The posterior cricoarytenoid muscles abduct the
vocal cords, whereas the lateral cricoarytenoid muscles are
Larynx
the principal adductors.
Phonation involves complex simultaneous
Trachea
actions by several laryngeal muscles. Damage to
the motor nerves innervating the larynx leads
FIGURE 19 1 Anatomy of the airway.
CHAPTER 19 Airway Management 311
Epiglottis
Hyoid bone
Thyrohyoid membrane
Superior cornu of
thyroid cartilage
Cuneiform cartilage (paired)
Thyroid cartilage lamina
Corniculate cartilage (paired)
Arytenoid cartilage (paired)
Cricothyroid ligament
Inferior cornu of
thyroid cartilage
Cricoid cartilage
Trachea
Anterior Posterior
FIGURE 19 2 Cartilaginous structures comprising the (With permission, from The Mayo Foundation.)
larynx.
V1
V2
V3
IX
V1 Ophthalmic division of trigeminal nerve
(anterior ethmoidal nerve)
SL
V2 Maxillary division of trigeminal nerve
(sphenopalatine nerves)
V3 Mandibular division of trigeminal nerve
(lingual nerve)
IL X IX Glossopharyngeal nerve
X Vagus nerve
SL Superior laryngeal nerve
IL Internal laryngeal nerve
RL Recurrent laryngeal nerve
RL
FIGURE 19 3 Sensory nerve supply of the airway.

TABLE 19 1 The effects of laryngeal Left Right

nerve injury on the voice.
Nerve Effect of Nerve Injury
Superior laryngeal nerve

Unilateral Minimal effects
Bilateral Hoarseness, tiring of voice
Recurrent laryngeal nerve

Unilateral Hoarseness
Bilateral
Acute Stridor, respiratory distress FIGURE 19 4 Carina.
Chronic Aphonia
Vagus nerve
Unilateral Hoarseness the thyroid cartilage. The superior thyroid artery is
Bilateral Aphonia
found along the lateral edge of the CTM.
The trachea begins beneath the cricoid cartilage and
extends to the carina, the point at which the right and left
mainstem bronchi divide ( Figure 19–4). Anteriorly, the
to a spectrum of speech disorders (Table 19– trachea consists of cartilaginous rings; posteriorly, the
1). Unilateral denervation of a cricothyroid trachea is membranous.
muscle causes very subtle clinical findings.
Bilateral palsy of the superior laryngeal nerve
may result in hoarseness or easy tiring of the ROUTINE AIRWAY
voice, but airway control is not jeopardized. MANAGEMENT
Unilateral paralysis of a recurrent laryngeal nerve
results in paralysis of the ipsilateral vocal cord, causing Routine airway management associated with
deterioration in voice quality. Assuming intact superior gen-eral anesthesia consists of:
laryngeal nerves, acute bilateral recurrent laryngeal nerve • Airway assessment
palsy can result in stridor and respiratory distress because
• Preparation and equipment check
of the remaining unopposed tension of the cricothyroid
• Patient positioning
muscles. Airway problems are less frequent in chronic
bilateral recurrent laryngeal nerve loss because of the • Preoxygenation
development of various compensatory mechanisms (eg, • Bag and mask ventilation (BMV)
atrophy of the laryngeal musculature). • Intubation (if indicated)
• Confirmation of endotracheal tube placement
Bilateral injury to the vagus nerve affects both
the superior and the recurrent laryngeal nerves. • Intraoperative management
Thus, bilateral vagal denervation produces flaccid, and troubleshooting
midpositioned vocal cords similar to those seen after • Extubation
administration of succinylcholine. Although phona-
tion is severely impaired in these patients, airway
control is rarely a problem. AIRWAY ASSESSMENT
The blood supply of the larynx is derived from branches Airway assessment is the fi rst step in successful
of the thyroid arteries. The cricothyroid artery arises from the airway management. Several anatomical and
superior thyroid artery itself, the first branch given off from functional maneuvers can be performed to estimate
the external carotid artery, and crosses the upper the difficulty of endotracheal intubation; however, it
cricothyroid membrane (CTM), which extends from the is important to note that successful ventilation (with
cricoid cartilage to or without intubation) must be achieved by
Hard palate
Uvula Hard palate
Soft palate
Pillars
A CLASS I CLASS II CLASS III CLASS IV
Vocal cords
Epiglottis
B GRADE I GRADE II GRADE III GRADE IV
FIGURE 19 5 A: Mallampati classification of oral

opening. B: Grading of the laryngeal view. A difficult (class III or IV ) during the preoperative
(Reproduced, with permission, from Mallampati SR:
orotracheal intubation (grade III or IV ) may be predicted examination of a seated patient.
by the inability to visualize certain pharyngeal structures

Clinical signs to predict difficult tracheal intubation [hypothesis].
Can Anaesth Soc J 1983;30:316.)
the anesthetist if mortality and morbidity are ■ Class II: the upper part of the
to be avoided. Assessments include: faucial pillars and most of the
uvula are visible.
• Mouth opening: an incisor distance of 3
■ Class III: only the soft and hard
cm or greater is desirable in an adult. palates are visible.
• Upper lip bite test: the lower teeth are ■ Class IV: only the hard palate is visible.
brought in front of the upper teeth. The
• Thyromental distance: the distance
degree to which this can be done
between the mentum and the superior
estimates the range of motion of the
thyroid notch. A distance greater than
temperomandibular joints.
3 fingerbreadths is desirable.
• Mallampati classification: a frequently
• Neck circumference: a neck
performed test that examines the size of
circumference of greater than 27 in is
the tongue in relation to the oral cavity. The
suggestive of difficulties in
greater the tongue obstructs the view of the
visualization of the glottic opening.
pharyngeal structures, the more difficult
intubation may be (Figure 19–5). Although the presence of these findings may
■ Class I: the entire palatal arch, not be particularly sensitive for detecting a difficult
including the bilateral faucial pillars, intubation, the absence of these findings is
are visible down to their bases. predictive for relative ease of intubation.
Increasingly, patients present with morbid obesity and

Oral & Nasal Airways
body mass indices of 30 kg/m2 or greater. Although some
Loss of upper airway muscle tone (eg, weakness of the
morbidly obese patients have relatively normal head and genioglossus muscle) in anesthetized patients allows the
neck anatomy, others have much redundant pharyngeal tongue and epiglottis to fall back against the pos-terior wall
tissue and increased neck circumference. Not only may of the pharynx. Repositioning the head or a jaw thrust is the
these patients prove to be difficult to intubate, but routine preferred technique for opening the airway. To maintain the
ventilation with bag and mask also may be problematic. opening, an artificial airway can be inserted through the
mouth or nose to maintain an air passage between the
tongue and the posterior pharyngeal wall ( Figure 19–6).
EQUIPMENT Awake or lightly anesthetized patients with intact laryngeal
Preparation is mandatory for all airway reflexes may cough or even develop laryngospasm during
management scenarios. The following equipment airway insertion. Placement of an oral airway is sometimes
is routinely needed in airway management facilitated by suppressing airway reflexes, and, in addition,
situations: sometimes by depressing the tongue with a tongue blade.
Adult oral airways typically come in small (80 mm [Guedel
• An oxygen source
No. 3]), medium (90 mm [Guedel No. 4]), and large (100 mm
• BMV capability [Guedel No. 5]) sizes.
• Laryngoscopes (direct and video)
• Several endotracheal tubes of different sizes
The length of a nasal airway can be estimated as the
• Other (not endotracheal tube) airway distance from the nares to the meatus of the ear and should
devices (eg, oral, nasal airways) be approximately 2–4 cm longer than oral airways. Because
• Suction of the risk of epistaxis, nasal airways are less desirable in
• Oximetry and CO2 detection anticoagulated or thrombocytopenic patients. Also, nasal
• Stethoscope air-ways (and nasogastric tubes) should be used with
caution in patients with basilar skull fractures, where there
• Tape
has been a case report of a nasogastric tube entering the
• Blood pressure and electrocardiography cranial vault. All tubes inserted through the nose (eg, nasal
(ECG) monitors airways, nasogastric
• Intravenous access
A B
FIGURE 19 6 A: The oropharyngeal airway in place. through the nose and extends to just above the epiglottis.
The airway follows the curvature of the tongue, pulling it (Modified and reproduced, with permission, from Face masks and
and the epiglottis away from the posterior pharyngeal airways. In: Understanding Anesthesia Equipment, 4th ed. Dorsch
wall and providing a channel for air passage. B: The JA, Dorsch SE, eds. Williams & Wilkins, 1999.)
nasopharyngeal airway in place. The airway passes
catheters, nasotracheal tubes) should be Orifice

lubricated before being advanced along the
floor of the nasal passage.
Body
Face Mask Design & Technique
The use of a face mask can facilitate the delivery
of oxygen or an anesthetic gas from a breathing
Rim
system to a patient by creating an airtight seal
with the patient’s face ( Figure 19–7). The rim of
FIGURE 19 8 The Rendell–Baker–Soucek pediatric
the mask is contoured and conforms to a variety face mask has a shallow body and minimal dead space.
of facial features. The mask’s 22 mm orifice
attaches to the breathing circuit of the anesthesia
machine through a right angle connector. Several
If the mask is held with the left hand, the right hand can
mask designs are available. Transparent masks
be used to generate positive pressure ven-tilation by
allow observation of exhaled humidified gas and
squeezing the breathing bag. The mask is held against the
imme-diate recognition of vomitus. Retaining
face by downward pressure on the mask body exerted by the
hooks surrounding the orifice can be attached to
left thumb and index fin-ger (Figure 19–9). The middle and
a head strap so that the mask does not have to be
continually held in place. Some pediatric masks ring finger grasp the mandible to facilitate extension of the
are specially designed to minimize apparatus atlanto-occipital joint. This is a maneuver that is easier to
dead space (Figure 19–8). teach than to describe. Finger pressure should be placed on
Effective mask ventilation requires both a gas- the bony mandible and not on the soft tissues supporting the
base of the tongue, which may obstruct the airway. The little
1 tight mask fit and a patent airway. Improper face
mask technique can result in continued
finger is placed under the angle of the jaw and used to thrust
the jaw anteriorly, the most important maneuver to allow
deflation of the anesthesia reservoir bag when the
venti-lation to the patient.
adjustable pressure limiting valve is closed,
usually indicating a substantial leak around the
mask. In contrast, the generation of high
breathing circuit pressures with minimal chest
movement and breath sounds implies an
obstructed airway or obstructed tubing.
Orifice
Retaining
hooks
Body Rim
FIGURE 19 7 Clear adult face mask.

FIGURE 19 9 One-handed face mask technique.
regularly changed to prevent injury. Care should

be used to avoid mask or finger contact with the
eye, and the eyes should be taped shut to
minimize the risk of corneal abrasions.
POSITIONING
When manipulating the airway, correct patient positioning is
required. Relative alignment of the oral and pharyngeal axes
is achieved by having the patient in the “sniffing” position.
When cervical spine pathology is suspected, the head must
be kept in a neutral position during all airway manipulations.
In line stabilization of the neck must be maintained during
airway management in these patients, unless appropriate
films have been reviewed and cleared by a radiologist or
neurological or spine surgeon. Patients with morbid obesity
should be positioned on a 30 upward ramp, as the
functional residual capacity (FRC) of obese patients
FIGURE 19 10 A difficult airway can often deteriorates in the supine position, leading to more rapid
be managed with a two-handed technique.
deoxygenation should ventilation be impaired.
In difficult situations, two hands may be needed to

provide adequate jaw thrust and to create a mask seal.
Therefore, an assistant may be needed to squeeze the PREOXYGENATION
bag, or the machine’s ventilator can be used. In such When possible, preoxygenation with face mask oxygen
cases, the thumbs hold the mask down, and the should precede all airway management interventions.
fingertips or knuckles displace the jaw forward (Figure Oxygen is delivered by mask for several minutes prior to
19–10 ). Obstruction during expiration may be due to anesthetic induction. In this way, the functional residual
excessive downward pressure from the mask or from a capacity, the patient’s oxygen reserve, is purged of
ball valve effect of the jaw thrust. The former can be nitrogen. Up to 90% of the normal FRC of 2 L following
relieved by decreasing the pressure on the mask, and
preoxygenation is filled with O 2. Considering the normal
the latter by releasing the jaw thrust during this phase of
oxygen demand of 200–250 mL/min, the preoxygenated
the respiratory cycle. It is often difficult to form an
patient may have a 5–8 min oxygen reserve. Increasing
adequate mask fit with the cheeks of edentulous
the duration of apnea without desaturation improves
patients. Positive pressure ventilation using a mask
safety, if ventilation following anesthetic induction is
should normally be limited to 20 cm of H2O to avoid
delayed. Conditions that increase oxygen demand (eg,
stomach inflation.
sepsis, pregnancy) and decrease FRC (eg, morbid
Most patients’ airways can be maintained with a face
obesity, pregnancy) reduce the apneic period before
mask and an oral or nasal airway. Mask ventilation for long
desaturation ensues.
periods may result in pressure injury to branches of the
trigeminal or facial nerves. Because of the absence of
positive airway pressures during spontaneous ventilation,
only minimal down ward force on the face mask is required BAG AND MASK VENTILATION
to create an adequate seal. If the face mask and mask Bag and mask ventilation (BMV) is the first step in
straps are used for extended periods, the position should be airway management in most situations, with the
exception of patients undergoing rapid sequence
intubation. Rapid sequence inductions avoid BMV to prevent airflow from exiting through the mouth are
avoid stomach inflation and to reduce the potential also available. Some are equipped with a port to
for the aspiration of gastric contents in nonfasted suction gastric contents. None offer the protection
patients and those with delayed gastric emptying. In from aspiration pneumonitis offered by a properly
emergency situations, BMV precedes attempts at sited, cuffed endotracheal tube.
intubation in an effort to oxygenate the patient, with
the understanding that there is an implicit risk of Laryngeal Mask Airway
aspiration. A laryngeal mask airway (LMA) consists of a
As noted above, the anesthetist’s left hand widebore tube whose proximal end connects to a
supports the mask on the patient’s face. The face is breathing circuit with a standard 15-mm connector,
lifted into the mask with the third, fourth, and fifth and whose distal end is attached to an elliptical cuff
fingers of the anesthesia provider’s left hand. The that can be inflated through a pilot tube. The deflated
fingers are placed on the mandible, and the jaw is cuff is lubricated and inserted blindly into the
thrust forward, lift ing the base of the tongue away hypopharynx so that, once inflated, the cuff forms a
from the posterior pharynx opening the airway. The lowpressure seal around the entrance to the larynx.
thumb and index finger sit on top of the mask. If the This requires anesthetic depth and muscle relaxation
airway is patent, squeezing the bag will result in the slightly greater than that required for the insertion of
rise of the chest. If ventilation is ineffective (no sign an oral airway. Although insertion is relatively simple
of chest rising, no end tidal CO2 detected, no mist in (Figure 19–11), attention to detail will improve the
the clear mask), oral or nasal airways can be placed success rate (Table 19–2). An ideally positioned cuff
to relieve airway obstruction secondary to redundant is bordered by the base of the tongue superiorly, the
pharyngeal tissues. Difficult mask ventilation is often pyriform sinuses laterally, and the upper esophageal
found in patients with morbid obesity, beards, and sphincter inferiorly. If the esophagus lies within the
craniofacial deformities. rim of the cuff, gastric distention and regurgitation
In years past, anesthetics were routinely become possible. Anatomic variations prevent
delivered solely by mask administration. In adequate functioning in some patients. However, if
recent decades, a variety of supraglottic an LMA is not functioning properly after attempts to
devices has permitted both airway rescue improve the “fit” of the LMA have failed, most
(when BMV is not possible) and routine practitioners will try another LMA one size larger or
anesthetic airway management (when smaller. The shaft can be secured with tape to the
intubation is not thought to be necessary). skin of the face.
2 The LMA partially protects the larynx from

SUPRAGLOTTIC pharyngeal secretions (but not gastric regurgi-
tation), and it should remain in place until the
AIRWAY DEVICES patient has regained airway reflexes. This is
Supraglottic airway devices (SADs) are used with both
usually signaled by coughing and mouth
spontaneously and ventilated patients during anesthesia. opening on command. The LMA is available in
They have also been employed as conduits to aid many sizes (Table 19–3).
endotracheal intubation when both BMV and endotracheal The LMA provides an alternative to ventilation
intubation have failed. All SADs consist of a tube that is through a face mask or TT (Table 19–4). Relative
connected to a respiratory circuit or breathing bag, which is contraindications for the LMA include patients with
attached to a hypopharyngeal device that seals and directs pharyngeal pathology (eg, abscess), pharyngeal
air-flow to the glottis, trachea, and lungs. Additionally, these obstruction, full stomachs (eg, preg-nancy, hiatal
airway devices occlude the esophagus with varying degrees hernia), or low pulmonary compliance (eg, restrictive
of effectiveness, reducing gas distension of the stomach. airways disease) requiring peak inspiratory
Different sealing devices to pressures greater than 30 cm H2O. Traditionally, the
LMA has been avoided in patients
A B
C D
FIGURE 19 11 A: The laryngeal mask ready for mouth. The nonintubating hand can be used to stabilize
insertion. The cuff should be deflated tightly with the rim the occiput. C: By withdrawing the other fingers and with
facing away from the mask aperture. There should be no a slight pronation of the forearm, it is usually possible to
folds near the tip. B: Initial insertion of the laryngeal mask. push the mask fully into position in one fluid movement.
Under direct vision, the mask tip is pressed upward Note that the neck is kept flexed and the head extended.
against the hard palate. The middle finger may be used to D: The laryngeal mask is grasped with the other hand and
push the lower jaw downward. The mask is pressed the index finger withdrawn. The hand holding the tube
forward as it is advanced into the pharynx to ensure that presses gently downward until resistance is encountered.
the tip remains flattened and avoids the tongue. The jaw (Reproduced, with permission, from LMA North America.)
should not be held open once the mask is inside the
with bronchospasm or high airway resistance, but new a substitute for tracheal intubation, the LMA has
evidence suggests that because it is not placed in the proven particularly helpful as a life saving
trachea, use of an LMA is associated with less temporizing measure in patients with difficult airways
bronchospasm than a TT. Although it is clearly not (those who cannot be ventilated or intubated)
because of
TABLE 19 2 Successful insertion of TABLE 19 3 A variety of laryngeal masks

a laryngeal mask airway depends with different cuff volumes are available
upon attention to several details. for different sized patients.
1. Choose the appropriate size ( Table 19–3) and Cuff
check for leaks before insertion. Mask Size Patient Size Weight (kg) Volume (mL)
2. The leading edge of the deflated cuff should be wrinkle free
and facing away from the aperture (Figure 19–11A). 1 Infant 6.5 2–4
3. Lubricate only the back side of the cuff. 2 Child 6.5–20 Up to 10
4. Ensure adequate anesthesia before attempting insertion.
5. Place patient’s head in sniffing position (Figure 19– 2½ Child 20–30 Up to 15
11B and Figure 19–23). 3 Small adult 30 Up to 20
6. Use your index finger to guide the cuff along the hard
palate and down into the hypopharynx until an 4 Normal adult 70 Up to 30
increased resistance is felt (Figure 19–11C). The
longitudinal black line should always be pointing 5 Larger adult 70 Up to 30
directly cephalad (ie, facing the patient’s upper lip).
7. Inflate with the correct amount of air ( Table 19–3).
8. Ensure adequate anesthetic depth during
patient positioning. performed under topical anesthesia and bilateral
9. Obstruction after insertion is usually due to a down superior laryngeal nerve blocks, if the airway must
folded epiglottis or transient laryngospasm. be secured while the patient is awake.
10. Avoid pharyngeal suction, cuff deflation, or Variations in LMA design include:
laryngeal mask removal until the patient is awake
(eg, opening mouth on command). • The ProSeal LMA, which permits passage of
a gastric tube to decompress the stomach
its ease of insertion and relatively high success rate • The I-Gel, which uses a gel occluder
(95% to 99%). It has been used as a conduit for an rather than inflatable cuff
intubating stylet (eg, gumelastic bougie), ventilating • The Fastrach intubation LMA, which is
jet stylet, flexible FOB, or small diameter (6.0-mm) designed to facilitate endotracheal
TT. Several LMAs are available that have been intubation through the LMA device
modified to facilitate placement of a larger TT, with or • The LMA CTrach, which incorporates a camera
without the use of a FOB. Insertion can be to facilitate passage of an endotracheal tube
TABLE 19 4 Advantages and disadvantages of the laryngeal mask airway compared with
face mask ventilation or tracheal intubation.1
Advantages Disadvantages
Compared with face mask Hands free operation More invasive

Better seal in bearded patients More risk of airway trauma
Less cumbersome in ENT surgery Requires new skill
Often easier to maintain airway Deeper anesthesia required
Protects against airway secretions Requires some TMJ mobility
Less facial nerve and eye trauma N2O diffusion into cuff
Less operating room pollution Multiple contraindications
Compared with tracheal Less invasive Increased risk of gastrointestinal aspiration

intubation Very useful in difficult intubations Less safe in prone or jackknife positions
Less tooth and laryngeal trauma Limits maximum PPV
Less laryngospasm and bronchospasm Less secure airway
Does not require muscle relaxation Greater risk of gas leak and pollution
Does not require neck mobility Can cause gastric distention
No risk of esophageal or endobronchial intubation
ENT,
1 ear, nose, and throat; TMJ, temporomandibular joint; PPV, positive-pressure ventilation.
Sore throat is a common side effect following

SAD use. Injuries to the lingual, hypoglossal, and
recurrent laryngeal nerve have been reported.
Correct device sizing, avoidance of cuff
hyperinflation, and gentle movement of the jaw
during placement may reduce the likelihood of such
injuries.
Esophageal–Tracheal Combitube
The esophageal–tracheal Combitube consists of two fused
tubes, each with a 15-mm connector on its proximal end
(Figure 19–12). The longer blue tube has an occluded distal
tip that forces gas to exit through a series of side
perforations. The shorter clear tube has an open tip and no
side perforations. The Combitube is usually inserted blindly
through the mouth and advanced until the two black rings on
the shaft lie between the upper and lower teeth. The
Combitube has two inflatable cuffs, a 100-mL proximal cuff FIGURE 19 13 King laryngeal tube.
and a 15-mL distal cuff, both of which should be fully inflated
after placement. The distal lumen of the Combitube usually
decompression. Alternatively, if the Combitube
comes to lie in the esophagus approximately 95% of the time
enters the trachea, ventilation through the clear
so that ventilation through the longer blue tube will force gas
tube will direct gas into the trachea.
out of the side perforations and into the larynx. The shorter,
clear tube can be used for gastric
King Laryngeal Tube
King laryngeal tubes (LTs) consist of tube with a small
esophageal balloon and a larger balloon for placement in the
hypopharynx (Figure 19–13). Both tubes inflate through one
inflation line. The lungs are infl ated from air that exits
between the two balloons. A suction port distal to the
esophageal balloon is present, permitting decompression of
the stomach. The LT is inserted and the cuffs inflated.
Should ventilation prove difficult, the LT is likely inserted too
deep. Slightly withdrawing the device until compliance
improves ameliorates the situation.
ENDOTRACHEAL INTUBATION
Endotracheal intubation is employed both for the
conduct of general anesthesia and to facilitate the
ventilator management of the critically ill.
Tracheal Tubes
Standards govern TT manufacturing (American
National Standard for Anesthetic Equipment; ANSI
Z–79). TTs are most commonly made from polyvi-nyl
chloride. In the past, TTs were marked “I.T.” or
FIGURE 19 12 Combitube.
Cuff Connector
Beveled tip
Murphy eye
Inflating tube
Pilot balloon
Valve
FIGURE 19 14 Murphy tracheal tube.
“Z–79” to indicate that they had been implant tested cuff (Figure 19–14). The valve prevents air loss after cuff
to ensure nontoxicity. The shape and rigidity of TTs inflation. The pilot balloon provides a gross indication of cuff
can be altered by inserting a stylet. The patient end infl ation. The inflating tube connects the valve to the cuff
of the tube is beveled to aid visualization and and is incorporated into the tube’s wall. By creating a
insertion through the vocal cords. Murphy tubes tracheal seal, TT cuffs permit positive pressure ventilation
have a hole (the Murphy eye) to decrease the risk of and reduce the likelihood of aspiration. Uncuffed tubes are
occlusion, should the distal tube opening abut the often used in infants and young children to minimize the risk
carina or trachea ( Figure 19–14). of pressure injury and postintubation croup; however, in
Resistance to airfl ow depends primarily on tube recent years, cuffed pediatric tubes have been increasingly
diameter, but is also affected by tube length and favored.
curvature. TT size is usually designated in
millimeters of internal diameter, or, less commonly, There are two major types of cuffs: high pres-
in the French scale (external diameter in millimeters sure (low volume) and low pressure (high volume).
multiplied by 3). The choice of tube diameter is Highpressure cuffs are associated with more
always a compromise between maximizing flow with ischemic damage to the tracheal mucosa and are
a larger size and minimizing airway trauma with a less suitable for intubations of long duration. Low-
smaller size (Table 19–5). pressure cuffs may increase the likelihood of sore
Most adult TTs have a cuff inflation system con-sisting throat (larger mucosal contact area), aspiration,
of a valve, pilot balloon, inflating tube, and spontaneous extubation, and difficult insertion
(because of the floppy cuff). Nonetheless, because
of their lower incidence of mucosal damage, low
TABLE 19 5 Oral tracheal tube
size guidelines. pressure cuffs are generally employed.
Cuff pressure depends on several factors:
Internal
inflation volume, the diameter of the cuff in relation
Age Diameter (mm) Cut Length (cm)
to the trachea, tracheal and cuff compliance, and
Full-term infant 3.5 12 intrathoracic pressure (cuff pressures increase with
coughing). Cuff pressure may increase during
Child 4  Age 14  Age
4 2
general anesthesia from diffusion of nitrous oxide
from the tracheal mucosa into the TT cuff.
Adult TTs have been modified for a variety of
Female 7.0–7.5 24
Male 7.5–9.0 24
specialized applications. Flexible, spiral wound, wire
reinforced TTs (armored tubes) resist kinking and
may prove valuable in some head and neck surgical the United States. The choice of blade depends
procedures or in the prone patient. If an armored tube on personal preference and patient anatomy.
becomes kinked from extreme pressure (eg, an awake Because no blade is perfect for all situations, the
patient biting it), however, the lumen will often remain clinician should become familiar and proficient
permanently occluded, and the tube will need replacement. with a variety of blade designs (Figure 19–16).
Other specialized tubes include microlaryngeal tubes,
double lumen endotracheal tubes (to facilitate lung isolation
and one lung ventilation), endotracheal tubes equipped with VIDEO LARYNGOSCOPES
bronchial blockers (to facilitate lung isolation and one lung In recent years, a myriad of laryngoscopy devices that utilize
ventila-tion), metal tubes designed for laser airway surgery video technology have revolutionized management of the
to reduce fire hazards, and preformed curved tubes for nasal airway. Direct laryngoscopy with a Macintosh or Miller blade
and oral intubation in head and neck surgery. mandates appropriate alignment of the oral, pharyngeal,
and laryngeal structures to facilitate a direct view of the
LARYGOSCOPES glottis. Various maneuvers, such as the “sniff-ing” position
A laryngoscope is an instrument used to examine the larynx and external movement of the larynx with cricoid pressure
and to facilitate intubation of the trachea. The handle usually during direct laryngoscopy, are used to improve the view.
contains batteries to light a bulb on the blade tip (Figure 19– Video or optically based laryngoscopes have either a video
15), or, alternately, to power a fiberoptic bundle that chip (DCI system, GlideScope, McGrath, Airway) or a lens/
terminates at the tip of the blade. Light from a fiberoptic mirror (Airtraq) at the tip of the intubation blade to transmit a
bundle tends to be more precisely directed and less diffuse. view of the glottis to the operator. These devices differ in the
Also, laryngoscopes with fiberoptic light bundles in their angulation of the blade, the presence of a channel to guide
blades can be made magnetic resonance imaging the tube to the glottis, and the single use or multiuse nature
compatible. The Macintosh and Miller blades are the most of the device.
popular curved and straight designs, respectively, in
Video or indirect laryngoscopy most likely offers

Flange minimal advantage in patients with uncomplicated
airways. However, use in these patients is valuable
as a training guide for learners, especially when the
Bulb Electrical trainee is performing a direct laryngoscopy with the
contact device while the instructor views the glottis on the
video screen. Additionally, use in uncomplicated
Blade airway management patients improves familiarity
with the device for times when direct laryngoscopy is
not possible.
Indirect laryngoscopes generally improve visualization
Handle of laryngeal structures in difficult airways; however,
visualization does not always lead to successful intubation.
An endotracheal tube stylet is recommended when video
laryngoscopy is to be performed. Some devices come with
stylets designed to facilitate intubation with that particular
device. Bending the stylet and endotracheal tube in a
manner similar to the bend in the curve of the blade often
facilitates passage of the endotracheal tube into the trachea.
FIGURE 19 15 A rigid laryngoscope. Even when the glottic opening is seen clearly, directing the
endotracheal tube into
Macintosh
Miller
Wisconsin
FIGURE 19 16 An assortment of laryngoscope blades.
the trachea can be difficult. Should the tube become caught adjusted to facilitate a child of age 5 years up
on the arytenoids, slightly pulling the blade farther out may to an adult ( Figure 19–18). The blade can be
better permit tube passage. disconnected from the handle to facilitate its
Indirect laryngoscopy may result in less insertion in morbidly obese patients in whom
dis-placement of the cervical spine; however, the space between the upper chest and head
all precautions associated with airway is reduced. The blade is inserted midline, with
manipulation in a patient with a possible the laryngeal structures viewed at a distance
cervical spine fracture should be maintained. to enhance intubation success.
Varieties of indirect laryngoscopes include:
• Various Macintosh and Miller blades in pediatric and
adult sizes have video capability in the Storz DCI
system. The system can also incorporate an optical
intubating stylet (Figure 19–17). The blades are
similar to conventional intubation blades, permitting
direct laryngoscopy and indirect video laryngoscopy.
Assistants and instructors are able to see the view
obtained
by the operator and adjust their maneuvers
accordingly to facilitate intubation or to
provide instruction, respectively.
• The McGrath laryngoscope is a portable video
laryngoscope with a blade length that can be FIGURE 19 17 Optical intubating stylet.
FIGURE 19 18 McGrath laryngoscope.

FIGURE 19 19 Glidescope.
• The GlideScope comes with disposable adult or acquired upper airway anomalies laryngoscopy with
and pediatric sized blades (Figure 19–19). direct or indirect laryngoscopes may be undesirable or
The blade is inserted midline and advanced impossible. A flexible FOB allows indirect visualization of the
until glottic structures are identified. The larynx in such cases or in any situation in which awake
GlideScope has a 60 angle, preventing direct intubation is planned (Figure 19–21). Bronchoscopes are
laryngoscopy and necessitating the use of constructed of coated glass fibers that transmit light and
stylet that is similar in shape to the blade. images by internal reflection (ie, a light beam becomes
• Airtraq is a single use optical laryngoscope trapped
available in pediatric and adult sizes
(Figure 19–20). The device has a channel
to guide the endotracheal tube to the
glottis. This device is inserted midline.
Success is more likely when the device is
not positioned too close to the glottis.
• Video intubating stylets have a video capability
and light source. The stylet is introduced, and
the glottis identified. Intubation with a video
stylet may result in less cervical spine
movement than with other techniques.
Flexible Fiberoptic Bronchoscopes

In some situations for example, patients with
unstable cervical spines, poor range of motion of the
temporomandibular joint, or certain congenital FIGURE 19 20 Airtraq optical laryngoscope.
A Aspiration channel B
Light source
Light source bundle
Objective lens covering

image bundle
Insertion tube
FIGURE 19 21 A: Cross section of a fiberoptic

bronchoscope. B: A flexible fiberoptic
Eyepiece bronchoscope with a fixed light source.
within a fiber and exits unchanged at the opposite not a risk-free procedure, and not all patients
end). The insertion tube contains two bundles of receiving general anesthesia require it. A TT is
fibers, each consisting of 10,000 to 15,000 fibers. generally placed to protect the airway and for airway
One bundle transmits light from the light source (light access. Intubation is indicated in patients who are at
source or incoherent bundle), which is either external risk of aspiration and in those undergoing surgical
to the device or contained within the handle (Figure procedures involving body cavities or the head and
19–21B), whereas the other provides a high neck. Mask ventilation or ventilation with an LMA is
resolution image (image or coherent bundle). usually satisfactory for short minor procedures such
Directional manipulation of the insertion tube is as cystoscopy, examination under anesthesia,
accomplished with angulation wires. Aspiration inguinal hernia repairs, extremity surgery, and so
channels allow suctioning of secretions, insufflation forth.
of oxygen, or instillation of local anesthetic.
Aspiration channels can be difficult to clean, and, if Preparation for Direct Laryngoscopy
not properly cleaned and sterilized after each use, Preparation for intubation includes checking equipment and
may provide a nidus for infection. properly positioning the patient. The TT should be examined.
The tube’s cuff inflation system can be tested by infl ating the
cuff using a 10-mL syringe. Maintenance of cuff pressure
TECHNIQUES OF DIRECT AND after detaching the syringe ensures proper cuff and valve
INDIRECT LARYNGOSCOPY & function. Some anesthesiologists cut the TT to a preset
INTUBATION length to decrease the dead space, the risk of bronchial

intubation, and the risk of occlusion from tube kinking (Table
Indications for Intubation 19–5). The connector should be pushed firmly into the tube
Inserting a tube into the trachea has become a routine part
to decrease the likelihood of disconnection. If a stylet is
of delivering a general anesthetic. Intubation is used, it should be inserted
Stylet fading indicates depleted batteries. An extra

handle, blade, TT (one size smaller than the
anticipated optimal size), and stylet should be
immediately available. A functioning suction
unit is needed to clear the airway in case of
unexpected secretions, blood, or emesis.
Successful intubation often depends on correct patient
positioning. The patient’s head should be level with the
anesthesiologist’s waist or higher to prevent unnecessary
back strain during laryngoscopy.
Direct laryngoscopy displaces pharyngeal soft
FIGURE 19 22 A tracheal tube with a stylet bent
to resemble a hockey stick. tissues to create a direct line of vision from the mouth
to the glottic opening. Moderate head elevation (5–
10 cm above the surgical table) and extension of the
into the TT, which is then bent to resemble a hockey stick atlantooccipital joint place the patient in the desired
(Figure 19–22). This shape facilitates intubation of an sniffing position (Figure 19–23). The lower portion of
anteriorly positioned larynx. The desired blade is locked the cervical spine is flexed by resting the head on a
onto the laryngoscope handle, and bulb function is tested. pillow or other soft support.
The light intensity should remain constant even if the bulb is Preparation for induction and intubation also
jiggled. A blinking light signals a poor electrical contact, involves routine preoxygenation. Administration of
whereas 100% oxygen provides an extra margin of safety in
FIGURE 19 23 The sniffing

position and intubation with a
Macintosh blade. (Modified and
reproduced, with permission, from Dorsch
JA, Dorsch SE: Understanding Anesthesia
10 cm
Equipment: Construction, Care, and
Complications. Williams & Wilkins, 1991.)
Epiglottis
Aryepiglottic fold
Ventricular fold
Vocal fold
Cuneiform
Glottis cartilage
Corniculate cartilage
FIGURE 19 24 Typical view of the glottis during laryngoscopy with a curved blade. (Modified and reproduced, with
permission, from Barash PG: Clinical Anesthesia, 4th ed. Lippincott, 2001.)
case the patient is not easily ventilated after clears the view for TT placement. The tip of a curved
induc-tion. Preoxygenation can be omitted in blade is usually inserted into the vallecula, and the
patients who object to the face mask; however, straight blade tip covers the epiglottis. With either
failing to preoxygenate increases the risk of rapid blade, the handle is raised up and away from the
desaturation fol-lowing apnea. patient in a plane perpendicular to the patient’s
Because general anesthesia abolishes the protective mandible to expose the vocal cords (Figure 19–24).
corneal reflex, care must be taken during this period not to Trapping a lip between the teeth and the blade and
injure the patient’s eyes by unintentionally abrading the leverage on the teeth are avoided. The TT is taken
cornea. Thus, the eyes are routinely taped shut, often after with the right hand, and its tip is passed through the
applying an ophthalmic ointment before manipulation of the abducted vocal cords. The “backward, upward,
airway. rightward, pressure” (BURP) maneuver applied
externally moves an anteriorly positioned glottis
Orotracheal Intubation posterior to facilitate visualization of the glottis. The
The laryngoscope is held in the left hand. With the TT cuff should lie in the upper trachea, but beyond
patient’s mouth opened the blade is introduced into the larynx. The laryngo-scope is withdrawn, again
the right side of the oropharynx with care to avoid the with care to avoid tooth
teeth. The tongue is swept to the left and up into the
floor of the pharynx by the blade’s flange. Successful
3 damage. The cuff is inflated with the least amount
of air necessary to create a seal dur-
sweeping of the tongue leftward ing positive pressure ventilation to minimize the
visualization of the tracheal rings and carina will

likewise confirm correct placement. Otherwise,
the tube is taped or tied to secure its position.
4 Although the persistent detection of CO2 by a

capnograph is the best confirmation of tra-
cheal placement of a TT, it cannot exclude bronchial
intubation. The earliest evidence of bronchial
intubation often is an increase in peak inspiratory
pressure. Proper tube location can be reconfirmed
by palpating the cuff in the sternal notch while
compressing the pilot balloon with the other hand.
5 The cuff should not be felt above the level of the

cricoid cartilage, because a prolonged
intralaryngeal location may result in postoperative
hoarseness and increases the risk of accidental
extubation. Tube position can also be
documented by chest radiography.
The description presented here assumes an
unconscious patient. Oral intubation is usually poorly
tolerated by awake, fit patients. Intravenous
sedation, application of a local anesthetic spray in
the oropharynx, regional nerve block, and constant
reassurance will improve patient acceptance.
A failed intubation should not be followed by
identical repeated attempts. Changes must be made
to increase the likelihood of success, such as
repositioning the patient, decreasing the tube size,
adding a stylet, selecting a different blade, using an
indirect laryngoscope, attempting a nasal route, or
FIGURE 19 25 Sites for auscultation of breath requesting the assistance of another anesthesiolo
sounds at the apices and over the stomach.
gist. If the patient is also difficult to ventilate with a
mask, alternative forms of airway management (eg,
LMA, Combitube, cricothyrotomy with jet ventilation,
pressure transmitted to the tracheal mucosa.
tracheostomy) must be immediately pursued. The
Overinflation beyond 30 mm Hg may inhibit
guidelines developed by the American Society of
capillary blood flow, injuring the trachea.
Anesthesiologists for the management of a difficult
Compressing the pilot balloon with the fingers is
airway include a treatment plan algorithm (Figure
not a reliable method of determining whether cuff 19–26).
pressure is either sufficient or excessive. Use of video or indirect laryngoscopes is dependent
After intubation, the chest and epigastrium are
upon the design of the device. Some devices are placed
immediately auscultated, and a capnographic tracing
midline without the requirement to sweep the tongue from
(the definitive test) is monitored to ensure
view. Other devices contain channels to direct the
intratracheal location ( Figure 19–25). If there is
endotracheal tube to the glottic opening. Practitioners
doubt as to whether the tube is in the esophagus or
should be familiar with the features of available devices well
trachea, repeat the laryngoscopy to confirm
in advance of using one in a difficult airway situation. The
placement. End tidal CO2 will not be produced if
com-bined use of a video laryngoscope and an intubation
there is no cardiac output. FOB through the tube and
Difficult Airway Algorithm

1. Assess the likelihood and clinical impact of basic management problems.
A. Difficult ventilation
B. Difficult intubation
C. Difficulty with patient cooperation or consent
D. Difficult tracheostomy
2. Actively pursue opportunities to deliver supplemental oxygen throughout the process of difficult airway management.
3. Consider the relative merits and feasibility of basic management choices:
A. Intubation attempts after
Awake intubation vs. induction of general anesthesia
B. Noninvasive technique for initial Invasive technique for initial

vs.
approach to intubation approach to intubation
C. Preservation of spontaneous Ablation of spontaneous
vs.
ventilation ventilation
4. Develop primary and alternative strategies.
A. Awake Intubation B. Intubation Attempts after Induction
of General Anesthesia
Airway approached by Airway secured by

Initial intubation Initial intubation attempts
noninvasive intubation invasive access*
attempts UNSUCCESSFUL
successful* FROM THIS POINT ONWARD
Succeed* FAIL CONSIDER:
1. Calling for help.
2. Returning to spontaneous ventilation
Cancel Consider feasibility Invasive airway 3. Awakening the patient
case of other options a accessa*
FIGURE 19 26
(Reproduced, with permission, from the American Society of
Face mask ventilation adequate Face mask ventilation not adequate
Consider/attempt LMA
LMA adequate* LMA not adequate or not feasible
Nonemergency Pathway Emergency Pathway

Ventilation adequate, intubation unsuccessful Ventilation inadequate, intubation unsuccessful
Call for help

Alternative approaches to intubationc
e
Emergency noninvasive airway ventilation
Successful intubation* FAIL after multiple attempts Successful ventilation* FAIL Emergency
invasive
airway
b* a d b*
Invasive airway ventilation Consider feasibility of other options Awaken patient access
Difficult Airway Algorithm developed Anesthesiologists Task Force on Management of the Difficult Airway.
Practice guidelines for management of the difficult airway: an updated
report by the American Society of Anesthesiologists Task Force on
2.
Management of the Difficult Airway. Anesthesiology 2003;98:1269.)

by the Americ an Soci ety o f Anest hesiol ogists. * Co nfir m tr ache al int ubati on o r L MA plac eme nt with exh aled C O
FIGURE 19 27 Bougie.
bougie often can facilitate intubation, when the

endotracheal tube cannot be directed into the
glot-tis despite good visualization of the
laryngeal opening (Figure 19–27).
Nasotracheal Intubation
Nasal intubation is similar to oral intubation except
that the TT is advanced through the nose and
nasopharynx into the oropharynx before
laryngoscopy. The nostril through which the patient
breathes most easily is selected in advance and
prepared. Phenylephrine nose drops (0.5% or
0.25%) vasoconstrict vessels and shrink mucous
FIGURE 19 28 Radiograph demonstrating a 7.0-mm
membranes. If the patient is awake, local anesthetic tracheal tube placed through the cribriform plate into the
ointment (for the nostril), spray (for the oropharynx), cranial vault in a patient with a basilar skull fracture.
and nerve blocks can also be utilized.
A TT lubricated with water soluble jelly is
introduced along the floor of the nose, below the breath sounds as a guide, it is directed toward the
inferior turbinate, at an angle perpendicular to the
glottis. When breath sounds are maximal, the
face. The tube’s bevel should be directed laterally
anesthetist advances the tube during inspiration in
away from the turbinates. To ensure that the tube
an effort to blindly pass the tube into the trachea.
passes along the floor of the nasal cavity, the
proximal end of the TT should be pulled cephalad.
The tube is gradually advanced, until its tip can be
Flexible Fiberoptic Intubation
visualized in the oropharynx. Laryngoscopy, as Fiberoptic intubation (FOI) is routinely
discussed, reveals the abducted vocal cords. Often performed in awake or sedated patients with
the distal end of the TT can be pushed into the problematic airways. FOI is ideal for:
trachea without difficulty. If difficulty is encountered, • A small mouth opening
the tip of the tube may be directed through the vocal
• Minimizing cervical spine movement
cords with Magill forceps, being careful not to
in trauma or rheumatoid arthritis
damage the cuff. Nasal passage of TTs, airways, or
nasogastric catheters carries greater risk in patients • Upper airway obstruction, such as
with severe midfacial trauma because of the risk of angioedema or tumor mass
intracranial placement (Figure 19–28). • Facial deformities, facial trauma
Although less used today, blind nasal intubation
FOI can be performed awake or asleep
of spontaneously breathing patients can be
via oral or nasal routes.
employed. In this technique, after applying topical
anesthetic to the nostril and pharynx, a breathing • Awake FOI: predicted inability to ventilate
tube is passed through the nasopharynx. Using by mask, upper airway obstruction
• Asleep FOI: Failed intubation, desire

for minimal C spine movement in
patients who refuse awake intubation
• Oral FOI: Facial, skull injuries
• Nasal FOI: A poor mouth opening
When FOI is considered, careful planning is

necessary, as it will likely add to the anesthesia
time prior to surgery. Patients should be informed
of the need for awake intubation as a part of the
informed consent process.
The airway is anesthetized with a local
anes-thetic spray, and patient sedation is
provided, as tolerated. Dexmedetomidine has
the advantage of preserving respiration while
providing sedation. Airway anesthesia is
discussed in the Case Discussion below.
If nasal FOI is planned, both nostrils are
prepared with vasoconstrictive drops. The nostril
through which the patient breathes more easily is
identified. Oxygen can be insufflated through the
suction port and down the aspiration channel of
the FOB to improve oxygenation and blow
secretions away from the tip. FIGURE 19 29 Correct technique for manipulating a
Alternatively, a large nasal airway (eg, 36F) can fiberoptic bronchoscope through a tracheal tube is
be inserted in the contralateral nostril. The breathing shown in the top panel; avoid curvature in the
bronchoscope, which makes manipulation difficult.
circuit can be directly connected to the end of this
nasal airway to administer 100% oxygen during
laryngoscopy. If the patient is unconscious and not
breathing spontaneously, the mouth can be closed spontaneously, grasping the tongue with gauze and
and ventilation attempted through the single nasal pulling it forward may also facilitate intubation.
airway. When this technique is used, adequacy of Once in the trachea, the FOB is advanced to
ventilation and oxygenation should be confirmed by within sight of the carina. The presence of
capnography and pulse oximetry. The lubricated tracheal rings and the carina is proof of proper
shaft of the FOB is introduced into the TT lumen. It is positioning. The TT is pushed off the FOB. The
important to keep the shaft of the bronchoscope acute angle around the arytenoid cartilage and
relatively straight (Figure 19–29) so that if the head epiglottis may prevent easy advancement of the
of the bronchoscope is rotated in one direction, the tube. Use of an armored tube usually decreases
distal end will move to a similar degree and in the this problem due to its greater lateral flexibility and
same direction. As the tip of the FOB passes through more obtusely angled distal end. Proper TT
the distal end of the TT, the epiglottis or glottis should position is confirmed by viewing the tip of the tube
be visible. The tip of the bronchoscope is an appropriate distance (3 cm in adults) above the
manipulated, as needed, to pass the abducted cords. carina before the FOB is withdrawn.
Having an assistant thrust the jaw forward or Oral FOI proceeds similarly, with the aid of
apply cricoid pressure may improve visualization various oral airway devices to direct the FOB
in difficult cases. If the patient is breathing toward the glottis and to reduce obstruction of
the view by the tongue.
FIGURE 19 30 Cricothyrotomy. Slide catheter into

trachea. (Photo contributor: Lawrence B. Stack, MD.) (Photo contributor: Lawrence B. Stack, MD.)
FIGURE 19 31 Cricothyrotomy. Incision at wire
entry site. Remove catheter and make incision at
the wire entry site.
SURGICAL AIRWAY
TECHNIQUES potentially disastrous subcutaneous emphysema.
Short (1 s) bursts of oxygen ventilate the patient.
“Invasive” airways are required when the “can’t
intubate, can’t ventilate” scenario presents and Sufficient outflow of expired air must be assured to
may be performed in anticipation of such avoid barotrauma. Patients ventilated in this manner
circumstances in selected patients. The options may develop subcutaneous or mediastinal
include: surgical cricothyrotomy, catheter or emphysema and may become hypercapneic despite
needle cricothyrotomy, transtracheal catheter adequate oxygenation. Transtracheal jet ventilation
with jet ventilation, and retro-grade intubation. will usually require conversion to a surgical airway or
Surgical cricothyrotomy refers to surgical tracheal intubation.
Should a jet ventilation system not be available, a 3-mL
incision of the CTM and placement of a breathing
tube. More recently, several needle/dilator syringe can be attached to the catheter and the syringe
cricothyrotomy kits have become available. Unlike plunger removed. A 7.0-mm internal
surgical cricothyrotomy, where a horizontal incision
is made across the CTM, these kits utilize the
Seldinger catheter/wire/dilator technique. A catheter
attached to a syringe is inserted across the CTM
(Figure 19–30). When air is aspirated, a guidewire
is passed through the catheter into the trachea (
Figure 19–31). A dilator is then passed over the
guidewire, and a breathing tube placed (Figure 19–
32).
Catheter based salvage procedures can also be
performed. A 16- or 14-gauge intravenous cannula is
attached to a syringe and passed through the CTM toward
the carina. Air is aspirated. If a jet ventilation system is
available, it can be attached. The catheter MUST be
secured, otherwise the jet pressure will push the catheter
(Photo contributor: Lawrence B. Stack, MD.)
out of the airway, leading to
FIGURE 19 32 Cricothyrotomy. Insert tracheostomy tube/introducer. Insert both devices over the wire and into the trachea.
diameter TT connector can be inserted into the administered to treat bronchospasm. Obese
syringe and attached to a breathing circuit or an patients may desaturate secondary to a reduced
ambu bag. As with the jet ventilation system, FRC and atelectasis. Application of positive end
adequate exhalation must occur to avoid expiratory pressure may improve oxygenation.
barotraumas. Should the end tidal CO2 decline suddenly,
Retrograde intubation is another approach to secure an pul-monary (thrombus) or venous air embolism
airway. A wire is passed via a catheter placed in the CTM. should be considered. Likewise, other causes of
The wire is angulated cephalad and emerges either through a sudden decline in cardiac output or a leak in the
the mouth or nose. The distal end of the wire is secured with circuit should be considered.
a clamp to prevent it from passing through the CTM. The wire A rising end tidal CO2 may be secondary
can then be threaded into an FOB with a loaded to hypoventilation or increased CO 2
endotracheal tube to facilitate and confirm placement. production, as occurs with malignant
Conversely, a small endotracheal tube can be guided by the hyperthermia, sepsis, a depleted CO2
wire into the trachea. Once placed, the wire is removed. absorber, or breathing circuit malfunction.
Alternatively, an epidural catheter can be placed via an Increases in airway pressure may indicate an
epidural needle in the CTM. After the distal end is retrieved obstructed or kinked endotracheal tube or reduced
from the mouth, an endotracheal tube may be passed over pulmonary compliance. The endotracheal tube
the catheter into the trachea. should be suctioned to confirm that it is patent and
the lungs auscultated to detect signs of broncho
spasm, pulmonary edema, endobronchial intubation,
or pneumothorax.
PROBLEMS FOLLOWING Decreases in airway pressure can occur
INTUBATION secondary to leaks in the breathing circuit or
Following apparently successful intubation, several inadvertent extubation.
scenarios may develop that require immediate
attention. Anesthesia staff MUST confirm that the
tube is correctly placed with bilateral ventilation TECHNIQUES OF EXTUBATION
immediately following placement. Detection of end Most often, extubation should be performed when a
tidal CO2 remains the gold standard in this regard, patient is either deeply anesthetized or awake. In
with the caveat that cardiac output must be present either case, adequate recovery from neuromuscular
for end tidal CO2 production. blocking agents should be established prior to
Decreases in oxygen saturation can occur following extubation. If neuromuscular blocking agents are
tube placement. This is often secondary to endobronchial used, the patient has at least a period of controlled
intubation, especially in small children and babies. mechanical ventilation and likely must be weaned
Decreased oxygen saturation perioperatively may be due to from the ventilator before extubation can occur.
inadequate oxygen delivery (oxygen not turned on, patient Extubation during a light plane of anesthesia (ie,
not ventilated) or to ventilation/perfusion mismatch (almost a state between deep and awake) is avoided
any form of lung disease). When saturation declines, the because of an increased risk of laryngospasm. The
patient’s chest is auscultated to confirm bilateral tube distinction between deep and light anesthesia is
placement and to listen for wheezes, rhonchi, and rales usually apparent during pharyngeal suctioning: any
consistent with lung pathology. The breathing circuit is reaction to suctioning (eg, breath holding, coughing)
checked. An intraoperative chest radiograph may be needed signals a light plane of anesthesia, whereas no
to identify the cause of desaturation. Intraoperative fiberoptic reaction is characteristic of a deep plane. Similarly,
bronchoscopy can also be performed and used to confirm eye opening or purposeful movements imply that the
proper tube placement and to clear mucous plugs. patient is sufficiently awake for extubation.
Bronchodilators and deeper planes of inhalation anesthetics Extubating an awake patient is usually asso-
are ciated with coughing (bucking) on the TT. This
reaction increases the heart rate, central venous pressure, TABLE 19 6 Complications of intubation.
arterial blood pressure, intracranial pressure,
intraabdominal pressure, and intraocular pressure. It may During laryngoscopy and intubation
Malpositioning
also cause wound dehiscence and increased bleeding. The Esophageal intubation
presence of a TT in an awake asthmatic patient may trigger Bronchial intubation
bronchospasm. Some practitioners attempt to decrease the Laryngeal cuff position
Airway trauma
likeli-hood of these effects by administering 1.5 mg/kg of
Dental damage
intravenous lidocaine 1–2 min before suctioning and Lip, tongue, or mucosal laceration
extubation; however, extubation during deep anesthesia Sore throat
may be preferable in patients who cannot tolerate these Dislocated mandible
Retropharyngeal dissection
effects (provided such patients are not at risk of aspiration Physiological reflexes
and/or do not have airways that may be difficult to control Hypoxia, hypercarbia
after removal of the TT). Hypertension, tachycardia
Intracranial hypertension
Intraocular hypertension
Regardless of whether the tube is removed when the
Laryngospasm
patient is deeply anesthetized or awake, the patient’s Tube malfunction
pharynx should be thoroughly suctioned before extubation Cuff perforation
While the tube is in place
to decrease the potential for aspiration of blood and
Malpositioning
secretions. In addition, patients should be ventilated with Unintentional extubation
100% oxygen in case it becomes difficult to establish an Bronchial intubation
airway after the TT is removed. Just prior to extubation, the Laryngeal cuff position
Airway trauma
TT is untaped or untied and its cuff is deflated. The tube is Mucosal inflammation and ulceration
withdrawn in a single smooth motion, and a face mask is Excoriation of nose
applied to deliver oxygen. Oxygen delivery by face mask is Tube malfunction
Fire/explosion
maintained during the period of transportation to the
Obstruction
postanesthesia care area. Following extubation
Airway trauma
Edema and stenosis (glottic, subglottic, or tracheal)
Hoarseness (vocal cord granuloma or paralysis)
Laryngeal malfunction and aspiration
COMPLICATIONS OF Laryngospasm
Negative pressure pulmonary edema
LARYNGOSCOPY &
INTUBATION
The complications of laryngoscopy and intubation
include hypoxia, hypercarbia, dental and airway to a range of complications from sore throat to
trauma, tube malpositioning, physiological tracheal stenosis. Most of these are due to
responses to airway instrumentation, or tube prolonged external pressure on sensitive airway
malfunction. These complications can occur during structures. When these pressures exceed the
laryngoscopy and intubation, while the tube is in capillary arteriolar blood pressure (approximately 30
place, or following extubation ( Table 19–6). mm Hg), tissue ischemia can lead to a sequence of
inflammation, ulceration, granulation, and stenosis.
Airway Trauma In flation of a TT cuff to the minimum pressure that
Instrumentation with a metal laryngoscope blade and creates a seal during routine positive pressure
insertion of a stiff TT often traumatizes delicate airway ventilation (usually at least 20 mm Hg) reduces
tissues. Tooth damage is a common cause of (relatively tracheal blood flow by 75% at the cuff site. Further
small) malpractice claims against anesthesiologists. cuff inflation or induced hypotension can totally
Laryngoscopy and intubation can lead eliminate mucosal blood flow.
Postintubation croup caused by glottic, laryngeal, or In contrast, inadequate insertion depth will
tracheal edema is particularly serious in children. The position the cuff in the larynx, predisposing the
efficacy of corticosteroids (eg, dexamethasone 0.2 mg/kg, patient to laryngeal trauma. Inadequate depth
up to a maximum of 12 mg) in preventing postextubation of insertion can be detected by palpating the
airway edema remains controversial; however, cuff over the thyroid cartilage.
corticosteroids have been demonstrated to be efficacious in Because no one technique protects against
children with croup from other causes. Vocal cord paralysis all possibilities for misplacing a TT, minimal
from cuff compression or other trauma to the recurrent testing should include chest auscultation, routine
laryngeal nerve results in hoarseness and increases the risk capnography, and occasionally cuff palpation.
of aspiration. The incidence of postoperative hoarseness If the patient is repositioned, tube placement
seems to increase with obesity, difficult intubations, and must be reconfirmed. Neck extension or lateral
anesthetics of long duration. Curiously, applying a water rotation most often moves a TT away from the
soluble lubricant or a local anesthetic containing gel to the carina, whereas neck flexion most often moves
tip or cuff of the the tube toward the carina.
TT does not decrease the incidence of postoperative sore At no time should excessive force be employed
throat or hoarseness, and, in some studies, actually during intubation. Esophageal intubations can result
increased the incidence of these complications. Smaller in esophageal rupture and mediastinitis. Mediastinitis
tubes (size 6.5 in women and size 7.0 in men) are presents as severe sore throat, fever, sepsis, and
associated with fewer complaints of postoperative sore subcutaneous air often manifesting as crepitus. Early
throat. Repeated attempts at laryngoscopy during a difficult intervention is necessary to avoid mortality. If
intubation may lead to periglottic edema and the inability to esophageal perforation is suspected, consultation
ventilate with a face mask, thus turning a bad situation into with an otolaryngologist or thoracic surgeon is
a life threatening one. recommended.
Errors of Tracheal Tube Positioning Physiological Responses

to Airway Instrumentation
6 Unrecognized esophageal intubation can
produce catastrophic results. Prevention of this
Laryngoscopy and tracheal intubation violate the
complication depends on direct visualization of the tip of patient’s protective airway reflexes and predictably
the TT passing through the vocal cords, careful lead to hypertension and tachycardia when
auscultation for the presence of bilateral breath sounds performed under “light” planes of general anesthesia.
and the absence of gastric gurgling while ventilating The insertion of an LMA is typically associated with
through the TT, analysis of exhaled gas for the presence less hemodynamic change. Hemodynamic changes
of CO2 (the most reliable automated method), chest can be attenuated by intravenous administration of
lidocaine, opioids, or β- blockers or deeper planes of
radiography, or the use of an FOB.
inhalation anesthesia in the minutes before
Even though it is confirmed that the tube is in the
laryngoscopy. Hypotensive agents, including sodium
trachea, it may not be correctly positioned. Overly
nitroprusside, nitroglycerin, esmolol and nicardipine,
“deep” insertion usually results in intubation of the
have also been shown to effectively attenuate the
right (rather than left) mainstem bronchus because of
transient hypertensive response associated with
the right bronchus’ less acute angle with
laryngoscopy and intuba-tion. Cardiac arrhythmias
7 the trachea. Clues to the diagnosis of bronchial
intubation include unilateral breath sounds,
particularly ventricular bigeminy sometimes occur
during intubation and may indicate light anesthesia.
unexpected hypoxia with pulse oximetry (unreliable
Laryngospasm is a forceful involuntary spasm
with high inspired oxygen concentrations), inability to
of the laryngeal musculature caused by sensory
palpate the TT cuff in the sternal notch during cuff
stimulation of the superior laryngeal nerve.
inflation, and decreased breathing bag compliance
Triggering stimuli include pharyngeal secretions
(high peak inspiratory pressures).
or passing a TT through the larynx during extubation. TABLE 19 7 Conditions associated

Laryngospasm is usually prevented by extubating with difficult intubations.
patients either deeply asleep or fully awake, but it
Tumors
can occuralbeit rarely in an awake patient. Cystic hygroma
Treatment of laryngospasm includes pro-viding Hemangioma
gentle positive-pressure ventilation with an Hematoma1
Infections
anesthesia bag and mask using 100% oxygen or
Submandibular abscess
administering intravenous lidocaine (1–1.5 mg/kg). If Peritonsillar abscess
laryngospasm persists and hypoxia develops, small Epiglottitis
doses of succinylcholine (0.25–0.5 mg/kg) may be Congenital anomalies
Pierre Robin syndrome
required (perhaps in combination with small doses of
Treacher Collins syndrome
propofol or another anesthetic) to relax the laryngeal Laryngeal atresia
muscles and to allow controlled Goldenhar syndrome
Craniofacial dysostosis
8 ventilation. The large negative intrathoracic
pressures generated by a struggling patient
Foreign body
Trauma
during laryngospasm can result in the Laryngeal fracture
Mandibular or maxillary fracture
development of negative pressure pulmonary
Inhalation burn
edema, even in healthy patients. Cervical spine injury
Whereas laryngospasm may result from an Obesity
abnormally sensitive reflex, aspiration can result Inadequate neck extension
Rheumatoid arthritis2
from depression of laryngeal reflexes following
Ankylosing spondylitis
prolonged intubation and general anesthesia. Halo traction
Bronchospasm is another reflex response to Anatomic variations
intubation and is most common in asthmatic Micrognathia
Prognathism
patients. Bronchospasm can sometimes be a Large tongue
clue to bronchial intubation. Other Arched palate
pathophysiological effects of intubation include Short neck
Prominent upper incisors
increased intracranial and intraocular pressures.
Can
1 occur postoperatively in patients who have had any neck surgery.
Also affects arytenoids making them immobile.
Tracheal Tube Malfunction 2
TTs do not always function as intended.

Polyvinyl chloride tubes may be ignited by
What are some important anesthetic
cautery or laser in an oxygen/nitrous
considerations during the preoperative evaluation
oxideenriched environment. Valve or cuff
of a patient with an abnormal airway?
damage is not unusual and should be excluded
prior to insertion. TT obstruction can result Induction of general anesthesia followed by
from kinking, from foreign body aspiration, or direct laryngoscopy and oral intubation is
from thick or inspissated secretions in the dangerous, if not impossible, in several situations.
lumen. (Table 19–7). To determine the optimal intubation
technique, the anesthesiologist must elicit an
airway history and carefully examine the patient’s
CASE DISCUSSION head and neck. Any available prior anesthesia
records should be reviewed for previous problems
Evaluation & Management in airway management. If a facial deformity is
of a Difficult Airway severe enough to preclude a good mask seal,
A 17-year-old girl presents for emergency positive-pressure ventilation may be impossible.
drain-age of a submandibular abscess.
Furthermore, patients with hypopharyngeal is more likely if the patient has recently eaten or
disease are more dependent on awake muscle if pus is draining from an abscess into the mouth.
tone to maintain airway patency. These two In either case, techniques that ablate laryngeal
groups of patients should generally not be reflexes (eg, topical anesthesia) should be
allowed to become apneic including induction of avoided.
anesthesia, sedation, or muscle paralysis until Cervical trauma or disease is a factor that
their airway is secured. should be evaluated prior to direct laryngoscopy.
If there is an abnormal limitation of the Cervical arthritis or previous cervical fusion may
temporomandibular joint that may not improve with make it difficult for the head to be put in the sniffing
muscle paralysis, a nasal approach with an FOB position; these patients are candidates for
should be considered. Infection confined to the bronchoscopy to secure the airway, as discussed
floor of the mouth usually does not preclude nasal previously. Trauma patients with unstable necks or
intubation. If the hypopharynx is involved to the whose neck has not yet been “cleared” are also
level of the hyoid bone, however, any trans- can-didates for bronchoscopy for tracheal
laryngeal attempt will be difficult. Other clues to a intubation. Alternatively, laryngoscopy with in line
potentially difficult laryngoscopy include limited stabilization can be performed ( Figure 19–33).
neck extension (35), a distance between the tip In the case under discussion, physical
of the patient’s mandible and hyoid bone of less examination reveals extensive facial edema that
than 7 cm, a sternomental distance of less than limits the mandible’s range of motion. Mask fit
12.5 cm with the head fully extended and the mouth does not seem to be impaired, however. Lateral
closed, and a poorly visualized uvula during radiographs of the head and neck suggest that
voluntary tongue protrusion. It must be stressed the infection has spread over the larynx. Frank
that because no examination technique is foolproof pus is observed in the mouth .
and the signs of a difficult airway may be subtle, the
anesthesiologist must always be prepared for Which intubation technique is indicated?
unanticipated difficulties. Routine oral and nasal intubations have been
The anesthesiologist should also evaluate the described for anesthetized patients. Both of these
patient for signs of airway obstruction (eg, chest can also be performed in awake patients. Whether
retraction, stridor) and hypoxia (agitation, rest- the patient is awake or asleep or whether intubation
lessness, anxiety, lethargy). Aspiration pneumonia is to be oral or nasal, it can be performed with
FIGURE 19 33 Technique for airway

management of a patient with suspected
spinal cord injury. One individual holds
the head firmly with the patient on a
backboard, the cervical collar left alone if
in place, ensuring that neither the head
nor neck moves with direct laryngoscopy.
A second person applies cricoid pressure
and the third performs laryngoscopy and
intubation.
direct laryngoscopy, fiberoptic visualization, or

video laryngoscopy techniques.
Intubation may be difficult in this patient; however,
there is pus draining into the mouth, and positive
pressure ventilation may be impossible. Induction of
anesthesia should, therefore, be delayed until after the
airway has been secured. Therefore, the alternatives
are awake fiberoptic intubation, awake video
laryngoscopy, or awake use of optical stylets. The final
decision depends on the availability of equipment and
the experiences and preferences of the anesthesia
caregivers.
Regardless of which alternative is chosen, an
emergency surgical airway may be necessary.
Therefore, an experienced team, including a surgeon,
FIGURE 19 34 Nerve block. While the tongue is
should be in the operating room, all necessary laterally retracted with a tongue blade, the base of the
equipment should be available and unwrapped, and palatoglossal arch is infiltrated with local anesthetic to
the neck should be prepped and draped. block the lingual and pharyngeal branches of the
glossopharyngeal nerve. Note that the lingual branches
What premedication would be of the glossopharyngeal nerve are not the same as the
appropriate for this patient? lingual nerve, which is a branch of the trigeminal nerve.
Any loss of consciousness or interference with

airway reflexes could result in airway obstruction or
aspiration. Glycopyrrolate would be a good choice
below the epiglottis (Figure 19–35). The hyoid
of premedication because it minimizes upper
bone is located, and 3 mL of 2% lidocaine is
airway secretions without crossing the blood brain
infiltrated 1 cm below each greater cornu, where
barrier. Parenteral sedatives should be very
the internal branch of the superior laryngeal nerves
carefully titrated. Dexmedetomidine and ketamine
penetrates the thyrohyoid membrane.
preserve respiratory effort and are frequently used
A transtracheal block is performed by
as sedatives. Psychological preparation of the
identifying and penetrating the CTM while the neck
patient, including explaining each step planned in
is extended. After confirmation of an intratracheal
securing the airway, may improve patient
position by aspiration of air, 4 mL of 4% lidocaine is
cooperation.
injected into the trachea at end expira-tion. A deep
What nerve blocks could be helpful inhalation and cough immediately
during an awake intubation? following injection distribute the anesthetic
The lingual and some pharyngeal branches throughout the trachea. Although these blocks
of the glossopharyngeal nerve that provide may allow the awake patient to tolerate
sensation to the posterior third of the tongue and intubation better, they also obtund protective
oropharynx are easily blocked by bilateral cough reflexes, depress the swallowing reflex,
injection of 2 mL of local anesthetic into the base and may lead to aspiration. Topical anesthesia
of the palatoglossal arch (also known as the of the pharynx may induce a transient
anterior tonsillar pillar) with a 25 gauge spinal obstruction from the loss of reflex regulation of
needle (Figure 19–34). airway caliber at the level of the glottis.
Bilateral superior laryngeal nerve blocks and a Because of this patient’s increased risk for
transtracheal block would anesthetize the airway aspiration, local anesthesia might best be limited to
What are some alternative techniques that

might be successful?
Other possible strategies include the retrograde
passage of a long guidewire or epidural catheter
through a needle inserted across the CTM. The
catheter is guided cephalad into the pharynx and
out through the nose or mouth. A TT is passed over
the catheter, which is withdrawn after the tube has
entered the larynx. Variations of this technique
include passing the retrograde wire through the
suction port of a flexible FOB or the lumen of a
reintubation stylet that has been preloaded with a
TT. These thicker shafts help the
TT negotiate the bend into the larynx more easily.
Obviously, a vast array of specialized airway
FIGURE 19 35 Superior laryngeal nerve block equipment exists and must be readily available for
and transtracheal block. management of difficult airways (Table 19–8 ).
Either of these techniques would have been difficult
in the patient described in this case
the nasal passages. Four percent cocaine has no

advantages compared with a mixture of 4%
lidocaine and 0.25% phenylephrine and can cause TABLE 19 8 Suggested contents of the
portable storage unit for difficult airway
cardiovascular side effects. The maximum safe
management.1,2
dose of local anesthetic should be calculated and
not exceeded. Local anesthetic is applied to the • Rigid laryngoscope blades of alternate design and
nasal mucosa with cotton-tipped applicators until a size from those routinely used.
• Tracheal tubes of assorted size.
nasal airway that has been lubricated with lidocaine • Tracheal tube guides. Examples include (but are not
jelly can be placed into the naris with minimal limited to) semirigid stylets with or without a hollow core
discomfort. Benzocaine spray is frequently used to for jet ventilation, light wands, and forceps designed to
topicalize the airway, but can produce manipulate the distal portion of the tracheal tube.
• Laryngeal mask airways of assorted sizes.
methemoglobinemia.
• Fiberoptic intubation equipment and assorted video
Why is it necessary to be prepared and indirect laryngoscopes.
• Retrograde intubation equipment.
for a surgical airway?
• At least one device suitable for emergency
Laryngospasm is always a possible nonsurgical airway ventilation. Examples include (but
complication of intubation in the nonparalyzed are not limited to) transtracheal jet ventilator, hollow
jet ventilation stylet, and Combitube.
patient, even if the patient remains awake.
• Equipment suitable for emergency surgical airway
Laryngospasm may make positive pressure access (eg, cricothyrotomy).
ventilation with a mask impossible. If • An exhaled CO2 detector.
succinylcholine is administered to break the spasm,
1Modified and used, with permission, from the American Society of
the consequent relaxation of pharyngeal muscles Anesthesiologists: Practice guidelines for management of the difficult
may lead to upper airway obstruction and airway: A report by the American Society of Anesthesiologists Task Force
on Management of the Difficult Airway. Anesthesiology 2003; 98:1272.
continued inability to ventilate. In this situation, an 2 The items listed in this table are suggestions. The contents of the portable storage
emergency cricothyrotomy may be lifesaving. unit should be customized to meet the specific needs, preferences, and skills of the
practitioner and healthcare facility.
Brain A: Pressure in laryngeal mask airway cuffs.

Anaesthesia 1996;51:603.
Cheney FW, Posner KL, Lee LA, Caplan RA,
Domino KB: Trends in anesthesia-related
death and brain damage. A closed claims
analysis. Anesthesiology 2006;105:1081.
Cook TM: A new practical classification of
laryngeal view. Anaesthesia 2000;55:274.
Cooper R: Complications associated with the
use of the GlideScope video laryngoscope.
Can J Anesth 2007;54:54.
El-Orbany M, Woehlck H, Ramez Salem M: Head
and neck position for direct laryngoscopy.
Anesth Analg 2011;113:103.
FIGURE 19 36 Intubating laryngeal mask airway.
Galvin E, van Doorn M, Blazques J, et al: A randomized
prospective study comparing cobra perilaryngeal
airway and laryngeal mask airway classic during
controlled ventilation for gynecological
because of the swelling and anatomic distortion
laparoscopy. Anesth Analg 2007;104:102.
of the neck that can accompany a
Hagberg C, Johnson S, Pillai D: Effective use of the
submandibular abscess. esophageal tracheal Combitube TN following
What are some approaches when the severe burn injury. J Clin Anesth 2003;15:463.
airway is unexpectedly difficult? Hohlrieder M, Brimacombe J, Von Goedecke A, et al:
Postoperative nausea, vomiting, airway morbidity, and
The unexpected difficult airway can present analgesic requirements are lower for the ProSeal
both in elective surgical patients and also in laryngeal mask airway than the tracheal tube in
emergency intubations in intensive care units, females undergoing breast and gynaecological
the emergency department, or general hospital surgery. Br J Anaesth 2007;99:576.
wards. Should video laryngoscopy fail even Holst B, Hodzovic I, Francis V: Airway trauma
after attempts with an intubating bougie, an caused by the Airtraq laryngoscope.
intubating LMA should be attempted (Figure Anaesthesia 2008;63:889.
19–36). If ventilation is adequate, an FOB can Houston G, Bourke P, Wilson G, et al: Bonfi ls
be loaded with a TT and passed through the intubating fiberscope in normal paediatric
LMA into the trachea. Correct tube position is airways. Br J Anaesth 2010;105:546.
Hurford WE: Orotracheal intubation outside the
confirmed by visualization of the carina .
operating room: anatomic considerations
and techniques. Respir Care 1999;44:615.
Jaeger JM, Durbin CG Jr: Special purpose
endotracheal tubes. Respir Care 1999;44:661.
SUGGESTED READING Jefferson M, Riff at F, McGuinness J, et al: The laryngeal
Armstrong J, John J Karsli C: A comparison between mask airway and otorhinolaryngology head and neck
the GlideScope Video Laryngoscope and direct surgery. Laryngoscope 2011;121:1620.
laryngoscope in paediatric patients with difficult Kaplan M, Ward D, Hagberg C, et al: Seeing is believing:
airways—a pilot study. Anaesthesia 2010;65:353. the importance of video laryngoscopy in
Aziz M, Healy D, Kheterpal S, et al: Routine clinical teaching and in managing the difficult airway.
practice effectiveness of the GlideScope in difficult Surg Endosc 2006;20:S479.
airway management. Anesthesiology 2011;114:34. Kim ES, Bishop MJ: Endotracheal intubation, but not
Bercker S, Schmidbauer W, Volk T, et al: A comparison laryngeal mask airway insertion, produces reversible
of seal in seven supraglottic airway devices using bronchoconstriction. Anesthesiology 1999;90:391.
a cadaver model of elevated esophageal pressure. Langeron O, Masso E, Huraux C, et al: Prediction of
Anesth Analg 2008;106:445. difficult mask ventilation. Anesthesiology 2000;92:1217.
Maharaj C, Costello J, McDonnell J, et al: The Airtraq as a Russi C, Hartley M, Buresh C: A pilot study of the
rescue airway device following failed direct laryngoscopy: King LT supralaryngeal airway use in a rural Iowa
a case series. Anaesthesia 2007;67:598. EMS system. Int J Emerg Med 2008;1:135.
Malik M, Maharaj C, Harte B, et al: Comparison of Shelly MP, Nightingale P: ABC of intensive care.
Macintosh, Trueview EVO2, GlideScope, and Respiratory support. BMJ 1999;318:1674.
Airwayscope laryngoscope use in patients with cervical Stauffer JL: Complications of endotracheal intubation
spine immobilization. Br J Anaesth 2008;101:723. and tracheostomy. Respir Care 1999;44:828.
Malik M, Subramanian R, Maharaj C, et al: Randomized Stix MS, O’Connor CJ Jr: Depth of insertion of the ProSeal
controlled trial of the Pentax AWS, GlideScope, and laryngeal mask airway. Br J Anaesth 2003;90:235.
Macintosh laryngoscopes in predicted difficult Tanoubi I, Drolet P, Donati F: Optimizing preoxygenation in
intubations. Br J Anaesth 2009;103:761. adults. Can J Anesth 2009;56:449.
Noppens R, Möbus S, Heid F, Schmidtmann I, Ting J: Temporomandibular joint dislocation after use of a
Werner C, Piepho T: Use of the McGrath laryngeal mask airway. Anaesthesia 2006;61:190.
Series 5 videolaryngoscope after failed direct Thompson AE: Issues in airway management in
laryngoscopy. Anaesthesia 2010;65:716. infants and children. Respir Care 1999;44:650.
Robitaille A, Williams S, Trembaly M, et al: Verghese C, Ramaswamy B: LMA-Supreme—a new
Cervical spine motion during tracheal intubation single-use LMA with gastric access: a report on its
with manual in-line stabilization direct clinical efficacy. Br J Anaesth 2008;101:405.
laryngoscopy versus GlideScope video Watson CB: Prediction of a difficult intubation: methods
laryngoscopy. Anesth Analg 2008;106:935. for successful intubation. Respir Care 1999;44:777.

Airway Management

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Airway Management 19 CHAPTER

The epiglottis prevents aspiration by covering the glottis the

which leads to the nasopharynx, and the mouth, which leads

FIGURE 19 3 Sensory nerve supply of the airway.

TABLE 19 1 The eﬀects of laryngeal Left Right

Superior laryngeal nerve

Recurrent laryngeal nerve

A CLASS I CLASS II CLASS III CLASS IV

B GRADE I GRADE II GRADE III GRADE IV

FIGURE 19 5 A: Mallampati classification of oral

orotracheal intubation (grade III or IV ) may be predicted examination of a seated patient.

by the inability to visualize certain pharyngeal structures

Increasingly, patients present with morbid obesity and

catheters, nasotracheal tubes) should be Orifice

FIGURE 19 7 Clear adult face mask.

regularly changed to prevent injury. Care should

In difficult situations, two hands may be needed to

2 The LMA partially protects the larynx from

TABLE 19 2 Successful insertion of TABLE 19 3 A variety of laryngeal masks

Compared with face mask Hands free operation More invasive

Compared with tracheal Less invasive Increased risk of gastrointestinal aspiration

Sore throat is a common side effect following

Video or indirect laryngoscopy most likely offers

FIGURE 19 16 An assortment of laryngoscope blades.

FIGURE 19 18 McGrath laryngoscope.

Flexible Fiberoptic Bronchoscopes

Light source bundle

Objective lens covering

FIGURE 19 21 A: Cross section of a fiberoptic

INTUBATION length to decrease the dead space, the risk of bronchial

Stylet fading indicates depleted batteries. An extra

FIGURE 19 23 The sniﬃng

visualization of the tracheal rings and carina will

4 Although the persistent detection of CO2 by a

5 The cuff should not be felt above the level of the

Difficult Airway Algorithm

B. Noninvasive technique for initial Invasive technique for initial

Airway approached by Airway secured by

(Reproduced, with permission, from the American Society of

Face mask ventilation adequate Face mask ventilation not adequate

LMA adequate* LMA not adequate or not feasible

Nonemergency Pathway Emergency Pathway

Call for help

Management of the Diﬃcult Airway. Anesthesiology 2003;98:1269.)

bougie often can facilitate intubation, when the

• Asleep FOI: Failed intubation, desire

When FOI is considered, careful planning is

FIGURE 19 30 Cricothyrotomy. Slide catheter into

Errors of Tracheal Tube Positioning Physiological Responses

or passing a TT through the larynx during extubation. TABLE 19 7 Conditions associated

TTs do not always function as intended.

FIGURE 19 33 Technique for airway

direct laryngoscopy, fiberoptic visualization, or

Any loss of consciousness or interference with

What are some alternative techniques that

the nasal passages. Four percent cocaine has no

Brain A: Pressure in laryngeal mask airway cuffs.

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