Pediatric Regional AnesthesiaAnalgesia

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Pediatric Regional Anesthesia/Analgesia
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Physiology

• Postoperative apnea in former premature infants
• Implications
• Immature CNS and BBB
• Regional alone decreases risk

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Pharmacology

• General and Implications
• Distribution
• CSF Volume
• Total Body Water
• Protein Binding
• Clearance
• Liver
• Renal
• Local Anesthetics
• Opioids

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Approximate CSF Volume
Cote, A Practice of Anesthesia for Infants and
Children
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? CSF Volume Implications

• Dosage of Drugs
• tetracaine 1 mg/kg epinephrine for spinal
• bupivacaine 0.5-1.0 ml/kg for caudal
• Duration of action
• e.g. Spinal Tetracaine with epinephrine

minutes
Cote, A Practice of Anesthesia for Infants and
Children
6
Total Body Water
of bodyweight
lt15 week fetus
4-6 months
Adult
Full Term
Clin Pharm, 14189, 1988
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General Pharmacology Implications

• ? CSF Volume ? ? dose ? duration
• ? Total Body Water ? ? IV dose, ? ? toxicity
• ? Protein Binding ? ? drug available ? ?
  toxicity
• ? Clearance ? ? t1/2 ? ? toxicity

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Local Anesthetics

• BE CAREFUL with repeated dosing and infusions
• Neurologic symptoms gt cardiac symptoms
• May not be able to illicit early neurologic
  symptoms in small children
• First sign may be a grand mal seizure

Anesth Analg, 75164, 1992 Anesth Analg, 75284,
1992 Anesth Analg, 75287, 1992
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Opioids

• Implications BE CAREFUL with opioids and infants
• Recommendation for opioids
• For IV, lt6 months of age ? consider apnea
  monitoring
• For CEI, lt12 months of age ? no fentanyl

Anesthesiology 661389, 1987
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Anatomy
Cote, A Practice of Anesthesia for Infants and
Children
11
Regional Anesthesia Only!

• Reduce risk of postoperative apnea in former
  premies
• Regional anesthesia alone will reduce risk of
  postoperative apnea
• Still need to monitor overnight
• Techniques
• Caudal 0.25 Bupivacaine (1ml/kg) Clonidine (1
  mcg/kg)
• Spinal Tetracaine, surgical anesthesia for 60-90
  minutes
• In other age groups, difficult to do regional
  alone

Anesthesiology 101A1470, 2004
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Combined Regional and General Anesthesia

• Usually regional anesthesia for postoperative
  analgesia
• Types
• Single dose caudal
• Continuous Epidural/Caudal Infusion
• Peripheral nerve blocks
• Field blocks
• Local infiltration

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Contraindications to Regional Anesthesia in
Pediatrics

• Parental refusal
• Need for intact sensory system for postoperative
  evaluation
• Sepsis
• Bleeding disorder
• Vertebral malformation or previous surgery
• Allergy

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Pediatric Regional AnesthesiaNeuroaxial
Techniques

• Caudal anesthesia and analgesia
• Single dose local anesthetic
• Morphine
• Clonidine
• Continuous infusion
• Spinal anesthesia

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Caudal Anesthesia Technique
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Caudal Anesthesia
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Caudal Anesthesia
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Caudal Anesthesia
Needle or Angiocath
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Caudal AnesthesiaWhere can it go?
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Single DoseLocal Anesthetic Volume

• Traditional
• 0.05 ml/seg/kg
• 0.5 ml/kg ? T10
• 1.0 ml/kg ? T6
• For longer duration or lower concentration
• 1.5 ml/kg ? T2

Anesthesiology 47527, 1977 Anesthesiology 7557,
1991
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Single DoseConcentration of Local Anesthetic

• Balance analgesia with risk of motor block
• 0.25 Bupivacaine (max 1 mg/kg)
• Excellent analgesia
• Risk of some motor block
• Shorter duration cases
• Recommend patients lt 18 months of age
• 0.175 Bupivacaine (max 1.5 mg/kg)
• Less motor block with good analgesia
• Higher levels
• Longer duration
• Mix 10 ml 7 ml 0.25 3 ml NS

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Single DoseCaudal Morphine

• 30 40 mcg/kg
• Provides analgesia for 12-24 hours
• No respiratory depression in over 500 children
• Nausea incidence similar to general anesthesia
• Less labor intensive
• Does not require special pain service
• Side Effects
• Nausea
• Itching
• Propofol therapy single dose
• Do not need to go to PICU

Anesthesiology 81A1348, 1994 J Clin Anesth
7640, 1995
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Local with Clonidine

• Clonidine in adults as oral sedative or adjunct
  to spinal or epidural
• Enhances and increases the effect of single shot
  bupivacaine caudal
• Risk sedation with gt 1mcg/kg
• At UTMB, use for caudal alone for premies and
  hernia repair

Anesthesiology 101A1470, 2004
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Awake Caudals in Neonates
Anesthesiology 101A1470, 2004
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Anesthesiology 101A1470, 2004
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Anesthesiology 101A1470, 2004
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Anesthesiology 101A1470, 2004
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Caudal/Epidural Anesthesia and Analgesia
Continuous Infusion

• Technique and Dose
• Caudal
• 16g angiocath with 19g epidural catheter
• Thread up to thoracic level
• Guard with clear steridrape
• Epidural-lumbar
• Use LOR to saline and continuous pressure method
• If thread up to thoracic level, need epidurogram
• Initial Dose 0.05 ml/seg/kg

Anesthesiology 69265, 1988 Anesthesiology
79400, 1993
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Caudal/Epidural Anesthesia and Analgesia
Continuous Infusion Rates and Types

• Rates
• lt1 y/o 0.1 to 0.2 ml/kg/hr
• gt1 y/o 0.1 to 0.4 ml/kg/hr
• less than 0.5 mcg/kg/hr fentanyl to start
• Types
• lt1 y/o 0.1 bupivacaine
• gt1 y/o 0.1 bupivacaine 3 mcg/ml fentanyl

Anesth Analg, 75164, 1992
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Continuous Caudal/Epidural Infusion Side
Effects and Treatment
Naloxone
Itching
Diphenhydramine
0.5-2 mcg/kg
Nausea
Metoclopramide
Naloxone
avoid sedating drugs
Naloxone
Urinary Retention
Straight Cath prn
Sedation
Turn Down Infusion
Respiratory Depression
Naloxone
10 mcg/kg
If infusion has fentanyl, then turn down
infusion may use naloxone
Cote, A Practice of Anesthesia for Infants and
Children
31
Spinal Anesthesia

• RARELY done
• Technique
• IV access
• 1.5" 22g beveled needle
• Dose
• Tetracaine 1 mg/kg and "whiff" (0.02 ml)
  epinephrine

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Approximate Distance Skin to Subarachnoid Space
MILLIMETERS
Premie
Newborn
5 months
Cote, A Practice of Anesthesia for Infants and
Children
33
Spinal AnesthesiaPositioning
Cote, A Practice of Anesthesia for Infants and
Children
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Spinal AnesthesiaCSF Returns
Cote, A Practice of Anesthesia for Infants and
Children
35
Spinal AnesthesiaInjection
Cote, A Practice of Anesthesia for Infants and
Children
36
Spinal Anesthesia

• Complications
• No hypotension seen in children under 6 years of
  age
• If blood encountered, difficult to identify CSF
• Limitations
• Procedure
• Duration 45 minutes
• Surgeon

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Penile Block
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Innervation

• Dorsal nerve of the penis
• 2nd to 4th sacral nerve roots
• Terminal branch of puedendal nerve
• Supplies the skin and the glans
• Gentiofemoral nerve (genital branch)
• Base of the penis and scrotum

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Anatomy

• Triangular space lying deep to the fascia
• Boundaries
• Above - symphysis pubis
• Below - corporosa cavernosa
• Anteriorly - Superficial fascia

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Anatomy

• Fascia splits on deep surface ? suspensory
  ligament
• Dorsal nerves and vessels lie in enclosed tight
  fascial sheath

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Landmarks

• Palpate symphysis pubis above the root of the
  penis
• Mark two points (0.5cm infant, 1cm adult/child)
  either side of the midline below the S.P.

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Technique

• 2 Injections
• 22-25G short bevelled needle
• Insert until touching the pubic symphysis
• Redirect lower and 3-5mm deeper

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• N EVER USE ADRENALINE

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Complications

• Intravascular injection
• Puncture of corpus cavernosum / dorsal vessels
• Ischaemia (rarely)

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Ilio-inguinal blockade
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Indications

• Surgical
• Field block (part of) for inguinal hernia repair
• Analgesic
• Post-op inguinal hernia repair
• Therapeutic
• Scar pain post herniorrhaphy
• Post-herpetic neuralgia

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Contraindications

• Local infection
• Anticoagulant therapy

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Innervation

• Sub-costal (T12)
• Iliohypogastric
• Genitofemoral
• Ilioinguinal

Iliohypogastric Genitofemoral Ilioinguinal
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Anatomy

• Subcoastal T12
• Ilioinguinal Iliohypogastric L1
• Genitofemoral L12

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Anatomy

• Ilioinguinal iliohyogastric nerve follow a
  circular course passing superior anterior iliac
  spine
• Lie within the abdominal wall muscles

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Adjacent to the ASIS

• External oblique
• Subcostal and Iliohypogastric N.
• Internal oblique
• Ilioinguinal N.
• Transversus Abdominis

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Landmarks

• Line drawn between anterior superior iliac spine
  and umbilicus
• Injection site 3cm medially along this line

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Subcostal and Iliohypogastric

• Needle perpendicular to skin
• 22G short bevelled needle
• 1st Click penetration of ext. ob. aponeurosis
  (8ml)

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• External oblique
• Subcostal and Iliohypogastric N.
• Internal oblique
• Ilioinguinal N.
• Transversus Abdominis

CLICK!
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Ilioinguinal

• 2nd Click

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• External oblique
• Subcostal and Iliohypogastric N.
• Internal oblique
• Ilioinguinal N.
• Transversus Abdominis

CLICK!
CLICK!
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Ilioinguinal

• 2nd Click
• Or,
• Posterolaterally to touch wing of the ilium and
  withdraw
• Further 8ml (Bupivicaine / Ropivicaine /
  Prilocaine)

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Complications

• Haematoma
• Infection
• Intravascular injection
• Intraperitoneal injection
• Femoral nerve block