Week 6 - Pediatric Caudal Epidurals

Question 1

What are the indications for a caudal epidural?

Answer 1

• Augmentation for GA and post-op analgesia
• Pediatric surgeries involving lower body
• Ureteral reimplantation, orchiopexy, complex hypospadias repair, inguinal herniorrhaphy, club foot repair, etc

Question 2

What are the contraindications for caudal epidural?

Answer 2

• Refusal, no parental consent
• Skin infection
• Sepsis
• Immunodeficiency
• Coagulopathy/thrombocytopenia
• Post-operative testing of motor/sensory function
• Anatomical – sacral dimple indicative of myelodysplasia
• Ultrasound to confirm anatomy

Question 3

Describe the anatomy of the caudal space

Answer 3

• Sacrum narrow, flat and a direct route to dural sac
• Conus medullaris @L3
• Dural sac @S3
• Incomplete ossification
• Thin ligamentum flavum
• Increased compliance and increased size of epidural space
• Increased intervertebral foramina – LA escape

Question 4

What is the physiology of a neuraxial block in the pediatric population?

Answer 4

• Relative CSF volume increase
• Increased CSF turnover
• Hemodynamic stability in children < 6 years with neuraxial block — small venous capacitance of lower extremities, lacking of resting sympathetic peripheral vascular tone

Question 5

Describe a caudal epidural technique

Answer 5

• Monitoring: standard ASA monitors
• Position: lateral decubitus, hips and knees flexed
• Operator: standing or sitting posteriorly vs anteriorly bending over

Question 6

What are the landmarks for a caudal epidural?

Answer 6

Equilateral triangle posterior superior iliac spines and sacral hiatus

Hiatus rostral of gluteal crease

*effect of gravity on skin

Question 7

What needle is used for a caudal epidural?

Answer 7

Short bevel 22g straight needle (decrease intravascular injection)

22g Jelco IV catheter (softer tip, decreased perforation, although kinking/sheering off tip)

PNB needle (dull, recognition of anatomical structure penetration, needs 3rd hand, increased cost)

Question 8

What are the steps of inserting the needle for a caudal epidural?

Answer 8

• Palpation of hiatus
• Needle insertion 45 degree angle
• Characteristic “give through sacrococcygeal ligament
• Drop angle

Question 9

How do you verify the needle is in the correct position for a caudal epidural?

Answer 9

• Needle hub open to air
• Aspiration
• Test dose (lidocaine with 1:200,000 epi) – controversial, sensitivity questioned in children

Question 10

What is the max dose of Bupivacaine for a caudal epidural?

Answer 10

2.5 mg/kg

CNS toxicity – seizures
Cardiac toxicity – therapy-resistant arrhythmias, cardiac arrest

Question 11

What local anesthetics are used for caudal epidurals?

Answer 11

Bupivacaine: 0.175% ideal for outpatient surgery – max sensory block w/ minimal motor block
not used as much anymore

Ropivacaine: 0.2% is ideal for caudal (good sensory/weak motor block)

Question 12

What is the max dose of Ropivacaine for caudal epidural? What is the onset and duration?

Answer 12

1 mL/kg of 0.2% Ropivacaine

Onset: 7-14 min
Duration 4-6 hours

Question 13

What is the dose of 20% intralipid for treatment of LAST in pediatrics?

Answer 13

1.5 mL/kg bolus then infusion of 0.25 mL/kg/hr

Question 14

What adjuvants are used in a caudal epidural injection?

Answer 14

• Clonidine (optimal dose 1-2 mcg/kg, sedation, bradycardia, HoTN, apnea in neonates)
• Ketamine (preservative-free not available in US)
• Neostigmine (PONV increased)
• Opioids (delayed resp depression)

Question 15

What are complications that can occur from a caudal epidural?

Answer 15

• Intravascular/intraosseous injection
• Epidural hematoma
• Neural injury
• Subarachnoid injection
• Epidural abscess
• Urinary retention (opioids)