Transcript PEDIATRIC REGIONAL ANESTHESIA

PEDIATRIC REGIONAL
ANESTHESIA
Jodie L. Johnson, M.D.
Assistant Professor of Clinical
Anesthesia
Riley Hospital for Children
Introduction
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Regional anesthesia being used more
frequently in pediatric setting
Most blocks placed at beginning of case
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“preemptive analgesia”
Some placed at end
Rarely used as sole anesthetic
General Principles
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Must acquire experience/dexterity with
RA in adults before employing
techniques in kids
Be aware of anatomical differences
between small child and adult
Be aware of pharmacokinetic
differences
General Principles
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Consider individual drug profiles
Skin infection in area of needle/catheter
insertion is contraindication
Coagulation disorders are
contraindication (unless corrected)
Chemotherapeutic agents cause
vascular fragility and thus central blocks
are contraindicated in pts on chemo
General Principles
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Have clear strategy
Good organization of equipment, drugs
and assistant helps avoid delays
Close monitoring just as important as
with GA
General Principles
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Significant development in regional
anesthesia in peds due to:
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Advances in safety information
Advances in pharmacology(Ropivicaine)
Improvements in equipment
Types of blocks limited only by skill and
interest of individual anesthesiologist
Benefits
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Analgesia provided by block reduces
amount of GA
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More rapid recovery
Decreased incidence of nausea & vomiting
Faster return of appetite
Earlier discharge
Decreased need for opioids
Benefits
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Regional block eliminates undesirable
autonomic reflexes
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Laryngospasm decreased
Cardiac dysrhythmias decreased
Muscle relaxation can be obtained with
suitable local anesthetic
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Can avoid use of muscle relaxants,
decrease risk of respiratory insufficiency
Benefits
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Easier to obtain immobilization of limb
after delicate surgery if child is painfree and there is some residual motor
block
Benefits
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Hypotension and urinary retention
rarely seen in children
Intra- and post-operative bleeding
reduced under neural blockade
A technique of choice if history of MH
Can avoid interference with respiratory
tract in premies with BPD
Benefits
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Diminished stress response
Fewer episodes of hypoxia
Greater cardiovascular stability
Faster return of GI function
Reduced need for postop vent support
Shorter stay in ICU
Safety
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Low complication rates
Lack of hypotensive response from
sympathectomy produced by LA
Loose perineurovascular sheaths
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Wider spead of LA from single injection site
Pharmacology and Physiology
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Increased risk of toxicity with local
anesthetics
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Infants have immature hepatic metabolism
Increased total body water
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Larger Volume of Distribution
Longer elimination half-life
Decreased plasma proteins ( more drug in
free/active form)
Rapid increase in blood levels due to higher
cardiac output/regional blood flow
Pharmacology
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Long-acting local anesthetics provide
for 6-12 hours of post-operative pain
relief
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Bupivicaine 0.2% to 0.5%
Ropivicaine 0.2%
Pharmacology
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Strictly follow maximal dosing
guidelines to prevent side effects
Physiology
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Decreased minimum anesthetic
concentration required to block impulse
conduction
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Nerves have thinner myelin sheaths
Nerves have smaller fiber diameter and a
shorter internodal distance
Adequate surgical block with smaller
concentrations of LA
Equipment
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Appropriate equipment decreases risk
of injury despite risks of increased
toxicity
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Use nerve stimulator in anesthetized kids
to improve success rate of peripheral nerve
blockade
1- or 2-inch insulated needles used
Caudal Blockade
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Most common regional block in children
Simple to perform
Easily adaptable to ambulatory
anesthesia practice
Greatly decreases risk of reflex
laryngospasm
Caudal - Anatomy
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Sacral hiatus easy to identify
Palpable large bony processes on each
side of hiatus called cornua
Hiatus covered by sacrococcygeal
membrane
Dural sac may extend to S3 or S4 in
infants (short distance between hiatus
and dural sac)
Caudal- Technique
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Lateral decubitus position
Palpate coccyx
Move finger gently from side to side
and proceed in cephalad direction
First double bony protuberance
encountered are sacral cornua which
define the sacral hiatus
Caudal - Technique
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Sterile prep/drape
21 g butterfly needle usually used
Insert at 45-60 degree angle with bevel
facing anteriorly
Distinct pop felt as sacrococcygeal
membrane pierced
Lower angle of needle and advance 2-3
mm
Caudal Blockade
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If outpatient, use just local anesthetic
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0.25% Bupiv or 0.2% Ropiv with epi
Test dose: 0.1 ml/kg with 5mcg/ml of epi (max 3ml)
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Look for signs of intravascular injection
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Increased heart rate > 10 bpm above baseline
Increased blood pressure
>25% change in T-wave amplitude
Doses:
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0.5cc/kg for LE/perineal surgery
0.75cc/kg for T-10 level
1cc/kg for lower thoracic level
Caudal Blockade
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For inpatients, can add PF MSO4 for 18
to 24 hours of postop analgesia
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50 mics/kg for perineal surgery
60 mics/kg for mid abdominal incision
70 mics/kg for sternotomy (open hearts)
Caudal Blockade
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Recent interest in Clonidine
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Less respiratory depression
Less nausea/vomiting
Less pruritis
Similar/prolonged analgesia VS. Morphine
? Dose
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1, 2 or 3 mcgs/ kg… to be determined
Caudal Blockade
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? Use of Clonidine in outpatients
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Some staff do not use at all
Some use if > 1 year of age
? Use of hydromorphone
? Use of ketamine
Caudal Blockade
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Major complications rare
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Intravascular injection with systemic
toxicity
Dural puncture causing high spinal
blockade
Infection (especially after interosseous
puncture/penetration)
Continuous Caudal Catheter
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Manufactured kits available
Styletted catheter increases passage to
thoracic level
Care taken to prevent fecal
contamination
Continuous Caudal Catheter
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Caudal approach to thoracic epidural
anesthesia used in children > 10 years
of age
Success related to less densely packed
epidural fat
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Easy cephalad passage of catheter
Continuous Caudal Catheter
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Correct placement confirmed by:
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Ease of injection
Negative aspiration
Radiographic imaging
Nerve Stimulation through catheter
Epidural Block
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Improved surgical outcomes:
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Decreased stress response
Fewer episodes of hypoxia
Decreased cardiac morbidity
Decreased pulmonary infections
Decreased thromboembolic events
Decreased blood loss
Faster return of GI function
Epidural Block
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Drugs Used:
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Ropivacaine/Bupivacaine
2 - Chloroprocaine
Morphine
Clonidine
Epidural Block
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Line drawn between two iliac crests
passes closer to L5 (vs. L3-4 interspace
in adults)
Under 1 year of age:
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Spinal cord ends at lower level (L3 vs. L1)
Dural sac ends at lower level (S4 vs. S2)
Epidural block
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Lateral decub position
Surgical side down
Hips and knees flexed by 90 degrees
Sterile prep/drape
“Loss of Resistance” technique with
saline
Epidural Block
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Epidural space more superficial in
children than adults
Guideline for determining epidural
depth:
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1mm/kg of body weight
Depth (cm) = 1 + 0.15 X age (years)
Depth (cm) = 0.8 + 0.05 X weight (kg)
Use shorter needles and extreme care
Epidural Block
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Dosing:
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Depends on upper level of analgesia
required
> 10 years of age:
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Volume to block one spinal segment
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V (in ml) = 1/10 X (age in years)
< 10 years old:
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0.04ml/kg/segment
Epidural Block
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Dosing:
Epidural Block
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Complications:
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Intrathecal injection
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High block
Postdural puncture headache
Intravascular injection/Local anesthetic
toxicity
Sympathectomy
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Hypotension
Bradycardia
Epidural Block
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Complications:
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Opioid –induced respiratory depression
Damage to neural structures
Infection
Epidural Hematoma  paraplegia
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< 1 in 150,000
Usually associated with anticoagulation
Epidural Block
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Although potential complications, there
are multiple benefits
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Decreased stress response
Decreased thromboembolic complications
Decreased pulmonary problems
Improved patient/parent satisfaction
Ilioinguinal and Iliohypogastric
Nerve Block
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Simple Block
Good pain relief for hernia repair,
hydrocelectomy and orchiopexy
Can be done at beginning of case for
both intraop and postop analgesia
May be done intraop under direct
visualization
Ilioinguinal Nerve Block
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Anatomy
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Nerves run between abdominal muscles
Close to ASIS
Both blocked by infiltration in area
medial to ASIS
Ilioinguinal Nerve Block
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25-gauge needle
Puncture skin 1 cm medial and 1 cm
inferior to ASIS
Three fan-shaped injections
Sub Q wheal as needle withdrawn
Bupiv 0.25% w/ epi up to 2mg/kg used
Penile Nerve Block
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Provides analgesia after superficial
surgery of penis
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Circumcision
Meatotomy
Blocks both dorsal nerves at base of
penis
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Anesthesia to distal two-thirds of penis
Penile Nerve Block
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Usually performed by surgeon
Avoid epinephrine
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May lead to ischemia of tissue
Complications:
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Intravascular injection
Hematoma formation
Brachial Plexus Block
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Can be done at three levels:
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Axillary
Interscalene
Supraclavicular
Excellent analgesia during/after surgery
on the upper extremities
Brachial Plexus Block
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Axillary approach used most
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Major complications rare
Interscalene/ Supraclavicular
approaches provide better analgesia of
upper arm/shoulder
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Higher complication rate : pneumothorax
and subarachnoid blockade
Brachial Plexus Block
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Can perform with one-injection
technique using nerve stimulator
Insert needle at 45 degree angle
immediately superior to artery high in
the axilla
Advance needle toward midclavicle until
evidence of nerve stimulation distally
Brachial Plexus Block
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Can also be performed by feeling
distinct “pop” upon entering
perineuroplexus sheath
After injection:
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Adduct arm
Hold distal pressure on artery
Brachial Plexus Block
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Transarterial approach not
recommended due to possible
hematoma formation with secondary
nerve compression
Parascalene Block
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Analgesia of shoulder joint
Avoids major structures in neck
Decreases chance of vascular injection
Spares phrenic nerve
Parascalene Block
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Place supine with roll under shoulder
Arm down at side
Head extended and turned to opposite
side
Line drawn between midpoint of clavicle
and transverse process of C6
Parascalene Block
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Insert needle perpendicular to skin at
junction of upper two thirds and lower
one third of drawn line
Nerve stimulator used to determine
depth
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Usually only 7 –30 mm below skin
Parascalene Block
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Complications:
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Puncture of external jugular vein
Pneumothorax
Horner’s Syndrome
Brachial Plexus Block
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Dosing:
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0.3- 0.5cc/kg of 0.25% Bupiv or 0.2%
Ropiv with 1:200,000 epi
Lower Extremity Blocks
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Lumbar Plexus (L1-L4)
Sciatic Nerve (L4-S3)
Femoral Nerve
Lumbar Plexus Block
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Provides analgesia to hip, thigh, groin
Lateral decub position
Lines drawn between iliac crests and
parallel to spinous processes the
through ipsilateral PSIS
Lumbar Plexus Block
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Insert needle 90 degrees to skin
through quadratus lumborum
Nerve stimulation appears as strong
contraction of quadriceps muscle
Lumbar Plexus Block
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Complications rare
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Epidural spread may occur if needle place
too medially
Summary
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Improvements in technique
Refinements in equipment
Regional anesthesia safely applied to
children