Regional Anesthesia

By: dr. Jadeny Sinatra, Sp.An, MH

FK Universitas Methodist Indonesia
Spinal Anesthesia

Epidural Anesthesia

Peripheral Nerve Blocks

 Spinal Anesthesia

Temporary interruption of nerve transmission within the subarachnoid space

produced by injection of a local anesthetic solution into the cerebrospinal fluid
Applied anatomy
Ligaments Lig. Nuchae (cervical) → supraspinous → sacrum
attached to spine Interspinous, Flavum, Anterior/Posterior
longitudinal
Epidural space
Duramater Spinal dura = brain meningeal dura
Spinal periosteum = brain endosteal dura
Ends at lower S2, pierced by filum terminale
Arachnoid Attached to dura, but capillary space between
the two = subdural space
barrier
Piamater Delicate vascular membrane investing spinal cord
Subarachnoid space Space between arachnoid and piamater
Contains arachnoid trabeculae and CSF
Extends from brain to spinal roots
Denticulate ligaments Lateral projection of pia, anchor spinal cord to dura
Applied anatomy

Vertebrae 7 cervical, 12 thoracic, 5 lumbar,

5 fused sacral, 5 coccygeal

Spinal nerves 8 cervical, 12 thoracic, 5 lumbar,

5 sacral, 1 coccygeal
Cervical above C7: exit above
vertebral level
C8 : exit below C7
Thoracic/lumbar : exit below
vertebral level
L5 exits between L5 and sacrum
Sacral : exits via anterior/posterior
foramina
General consideration

Preoperative assessment

 GA
detail of the procedure to be performed
anticipated length
patient position
a complete review of any co-existing diseases
preexisting neurologic abnormalities
history of abnormal bleeding

The area where the block is to be administered should be examined

potential difficulties or pathology

 detailed explanation
reassured
additional sedation and general anesthesia
Contraindications

Absolute
Patient refusal
Localized infection at skin puncture
Generalized sepsis (septicemia, bacteriemia)
Coagulopathy
Increased intracranial pressure

Relative
Localized infection peripheral to regional technique site
Hypovolemia
Central nervous system disease
Chronic back pain
Physiology
Cardiovascular

Hypotension is directly proportional to the degree of sympathetic blockade

sympathetic blockade  vasodilation, venodilation
  Systemic vascular resistance
 Capacitance
 Venous return
Hypotension marked inpatients who are:
hypovolemic
elderly
have obstruction to venous return
pregnancy

can be minimized with: prehydration, vasopressors, anticholinergics

Physiology
Respiratory

Low spinal  no effect

Higher block level  progressive ascending intercostal muscle paralysis
diaphragmatic function mediated by the phrenic nerve

poor respiratory reserve (morbidly obese, COPD)

 profoundly impaired
intercostal and abdominal muscle paralysis
  the efficiency of coughing
Physiology
Visceral effects

Bladder
sacral blockade (S2-S4)
 atonic bladder
able to retain large volume of urine
blockade of sympathetic efferent (T5-L1)
  sphinchter tone
urinary retention

Intestine
sympathetic blockade (T5-S1)
 promotility effect of the gut
Physiology

Renal function

Renal blood flow

maintained  urine production is unaffected
 autoregulation by local tissue factors

except with severe hypotension

Physiology
Thermoregulation

Vasodilation
redistribution of the heat
central  peripheral
 heat loss
 hypothermia
Technique
Spinal needle

Cutting tip
Quincke

Pencil-point  lateral opening

reduce the incidence of postdural puncture headache
splitting rather than cutting dural fibers during insertion
Sprotte
Whitacre
Technique

Patient position

Lateral decubitus
Sitting
in obese patient
to assist in identification of the midline
Technique
Procedure

L2-3, L3-4, or L4-5 interspace

Bony marker
iliac crest spinous process
spinous processes of L4
Aseptis & antisepsis
avoid contamination of spinal kit
potentially neurotoxic
Technique
Procedure

Needle placement

always keep the stylet in place

the needle lumen does not become plugged with tissue
if paresthesia occur
immediately withdraw the needle, reposition the needle
advance the needle until increased resistance is felt
as it passed the ligamentum flavum
beyond this  sudden loss of resistance
as the needle “pops” through the dura
remove the stylet
confirm correct placement by noting free flowing of CSF
Technique
Procedure

Administration of anesthetic

connect the syringe containing a predetermined dose of local anesthetic

aspirate CSF into the syringe
confirms free flow
inject the drug slowly
repeat aspiration of CSF at the end of injection
reconfirms the needle point is still within the subarachnoid space
remove the needle
Technique
Procedure

Monitoring

closely, every 60 – 90 seconds

blood pressure
pulse
determine the ascending anesthetic level
pinprick
cold alcohol swab
stabilization of the local anesthetic level
± 20 minutes
Determinants of level of spinal blockade

Drug dose
Drug volume
Baricity of local anesthetic solution
hyperbaric solutions
by mixing the drugs with dextrose
flows by gravity  to the most dependent parts of the CSF column
isobaric solutions
less dependent on patient position
hypobaric solutions
by mixing the drugs with sterile water  rise to the highest part of the CSF column
Determinants of Level of Spinal Blockade

Turbulence of CSF
rapid injection
barbotage
coughing
Increased intraabdominal pressure
pregnancy
obesity
intraabdominal tumors
 pressure within the inferior vena cava
 collateral circulation  epidural veins
reducing the volume of CSF within the vertebral column
 permits greater spread of injected local anesthetic
Spinal curvatures
lumbar lordosis
thoracic kyphosis
influence the spread local anesthetic solution
Determinant Duration of Spinal Blockade

Drugs and dose

specific for each drug

Drug Level (mg) Duration (min)

T-10 T-8T-6

Tetracaine 10 12 14 90 – 120
Bupivacaine 7.5 9.0 10.5 90 – 120
Lidocaine 50 60 70 30 – 90

Adjuvant drugs
Vasoconstrictors
epinephrine, phenylephrine
Opioids
α-2 reseeptor agonist
Factors affecting subarachnoid local anesthetic injections

Determinant of spread
Major factors
Baricity of solution
Position of patients (except isobaric solution)
Dose and volume of drug injected (except isobaric solution)
Minor factors
Level of injection
Speed of injection/barbotage
Size of needle
Physical status of patients
Intraabdominal pressure
Determinant of duration
Drug used
Dose injected
Presence of adjuvant drugs, eg. vasoconstrictor
Total spread of blockade
 Levels and significance of sensory blockade

Cutaneous Segmental Significance

Level Level

5th digit C8 All cardioaccelerator fibers (T1-T4) blocked

Inner aspect of arm T1 – T2 Some degree of cardioaccelerator fibers blocked
and forearm
Apex of axilla T3 Easily determined landmark
Nipple T4 - T5 Possibility of cardioaccelerator blockade
Tip of xiphoid T7 Splanchnics (T5 – L1) may be blocked
Umbilicus T10 Sympathetic nervous system blockade limited to legs
Inguinal ligament T12 No sympathetic nervous system blockade
Outer side of footS1 S1 Confirms block of the most difficult nerve root to
anesthetize
Epidural Anesthesia
Physiology
Neural blockade

Local anesthetic placed in the epidural space

acts directly on the spinal nerve roots
gains access to the CSF by uptake through the dura

The onset of block is slower than with spinal anesthesia

The intensity of the sensory and motor block is less

Anesthesia develops in a segmental manner

Physiology
Cardiovascular

Hypotension
 spinal anesthesia

Large doses of local anesthetic used

may be absorbed into the systemic circulation
 may depress the myocardium

Epinephrine used with local anesthetics

may be absorbed
 producing systemic effect
 tachycardia & hypertension
Technique
Epidural needles

Tuohy
Blunt tip
Weiss

Patient position

Sitting
Lateral
Technique

Approaches

Lumbar
Thoracic
provides upper abdominal and thoracic anesthesia with a smaller dose of local anesthetic
postoperative analgesia without lower extremity blockade

thoracic vertebral spinous processes are much more sharply angulated downward
 the tip of the superior spinous process overlies the lamina of the vertebra below
 epidural needle should be directed in a more cephalad direction

risk of producing trauma to the underlying spinal cord if dural puncture occurs

paramedian approach
Technique
Needle placement

Loss of resistance technique

air or saline
constant pressure to the plunger of the syringe while slowly advance the needle
when the bevel enters the epidural space  “loss of resistance”
Hanging drop technique
a drop of fluid placed on the hub of the epidural needle
will retract into the needle as the tip of the needle advanced into epidural space
negative pressure  tenting of the dura by the needle tip
may be altered by transmitted changes in intraabdominal or
intrathoracic pressure
pregnancy
obesity
Technique
Catheter placement

To permits repeated injections of local anesthetic

for prolonged procedures
provides a route for postoperative analgesia

Thread a 20-G radiopaque catheter through the epidural needle

Multipores catheters
the distance from the catheter tip to the most proximal lateral hole should be noted
Advanced the catheter tip 3 to 5 cm beyond the needle tip into the epidural space
Withdraw the needle over the catheter
Fix the catheter
measure the distance from the surface of the patient’s back to the epidural space
Technique
Test dose

Through the needle  single-dose technique

Through the catheter  continuous technique

3 mL 1.5 - 2% Lidocaine with 1:200,000 epinephrine

CSF  spinal block will occur rapidly
blood vessels   heart rate 20 – 30%
perioral numbness
metallic taste
tinnitus
palpitations
Technique

Injection of anesthetic

Aspirate the catheter or needle before each injection

checking for the appearance of blood or CSF
3- to 5-mL increments every 3 to 5 minutes until the total dose is given
 Spinal vs Epidural Anesthesia

Spinal anesthesia  rapid onset

Epidural  prolonged anesthesia and analgesia

postoperative pain management
General Principles

Local anesthetic
Low concentration  permits injection of large volumes of solution
 improves the reliability
Addition of epinephrine (1:200.000) is recommended
 to prolong the duration of anesthesia
except:
block of end-organ
IV regional anesthesia
General Principles

Nerve localization
Anatomic landmarks
bone prominent
arterial pulsation
less reliable landmarks
large volume of local anesthetic solution
paresthesia technique
avoid intraneural injection
Nerve stimulator
low current (0.1 – 10 mA)
insulated needle
General Principles

Equipment
Disposable kits
Needles
short bevel
Syringes
three-ring/control ring syringes
 to facilitate control of injection
to allow the operator to refill the syringe with one hand
Antiseptics
General Principles

Complications of Peripheral Nerve Block

Systemic toxicity of local anesthetic solution
Peripheral nerve injury
intraneural injection
positional injury
Pain at injection site
Local hematoma
Patient Preparation

Patient selection

Contraindications to Peripheral Nerve Block

Patient refusal
Local infection at block site
Coagulopathy
Pre-existing neuripathy
Patient Preparation

Monitoring
standard
!!!
Maintain verbal contact
assessing mental status
detecting early signs of systemic local anesthetic toxicity
Patient Preparation

Discharge criteria
acceptable mental status
hemodynamic stable
residual numbness
Specific techniques

Upper extremity
innervation: anterior rami of the C5 – T1
Brachial plexus block
Interscalene approach
interscalene groove at the level of the cricoid cartilage
Supraclavicular approach
interscalene groove, midpoint of the clavicle  the first rib
pneumothorax
Axillary approach
axillary artery
neuropathy
hematoma
intravascular injection
Specific techniques

Upper extremity
Elbow block
wrist block
Median nerve
Radial nerve
Ulnar nerve
Intravenous regional anesthesia (IVRA/Bier’s block)
lidocaine 0.5% without epinephrine
tourniquet
systemic toxicity of local anesthetic
Specific techniques
Lower extremity
Two major plexus
the lumbar plexus
anterior rami of the L1-4 spinal nerves
ilioinguinal nerve
iliohypogastric nerve
lateral femoral cutaneous nerve
femoral nerve
obturator
the sacral plexus
anterior rami of the L4-5 and S1-3
posterior cutaneous nerve of the thigh
sciatic nerve
tibial nerve
common peroneal nerve
superficial peroneal nerve
deep peroneal nerve
sural nerve
Specific techniques

Lower extremity
Indications
entire lower extremity
 requires blocking of both lumbar and sacral plexuses
 unpopular
limited area
 single injection
when RA is preferable but central neuraxis block is contraindicated
Specific techniques

Lower extremity
Indications
For tourniquet pain
LFC + femoral block
Open operation of the knee
lumbar + sciatic block
Operation distal to the knee
sciatic block + saphenus component of femoral nerve
ankle block
deep peroneal
superficial peroneal
saphenus
posterior tibial
sural
Thank you