Regional Anesthesia for Infants and Children

Abstract

Regional anesthesia in children differs in many respects from adults. Most pediatric regional blocks are placed after induction of anesthesia to provide post-operative analgesia. Complications associated with this approach are very low as shown by several large prospective surveys. Local anesthetic spread is generally more reliable than in adults, but higher volumes in relation to body weight are usually required for neuraxial single shot blocks and infusions. Single shot blocks and wound infiltration are commonly used to minimize opiate use in day case surgery and to reduce the distress frequently seen when small children emerge from anesthesia with inadequate analgesia. The pharmacokinetics of local anesthetic agents are different in neonates and young children compared with adults. There is a high risk of toxicity in neonates and infants because of reduced protein binding and metabolism. Local anesthetic additives are not as well studied and less frequently used in children compared with adults. Clonidine however, is frequently added during caudal block to prolong duration and provide sedation. Sedation is sometimes an important addition to regional techniques, because good analgesia alone does not guarantee lack of distress, particularly in pre-school children who may be distressed by their environment, restriction of movement or effects of surgery or equipment.

Review Questions

• 1. Describe anatomy and technique to perform caudal epidural block for postoperative pain relief for circumcision in a 3 year old. What volume and concentration of agents will be required?

  Why isn’t a fluid load required before performing the block?

• 2. What factors need to be considered when running local anesthetic infusions in neonates?

• 3. What are the local anesthetic options to provide pain relief after bilateral inguinal hernia repair in a 2 year old? What are the risks and benefits of each technique?

• 4. You are about to perform a caudal block for a 8 month old baby and you notice a midline indentation in the skin in the sacral region. How will you decide if it is still safe to proceed with the caudal?

• 5. You plan to perform a spinal block in 3 month old baby. What level will you insert the needle? What local anesthetic will you use, and how much will you inject? How long is this block likely to last? If the baby becomes apneic, what might this indicate?