All children have beautiful (Fig. 39.1) anatomy, which makes pediatric regional anesthesia especially enjoyable. Although pediatric regional anesthesia was historically preceded by descriptions in the literature of adult-based regional anesthesia, Dr. H. Tyrell Gray in London reported and discussed the use of spinal anesthesia in children in 1909.¹ Gray concluded that the benefits of regional anesthesia in the pediatric population included “absolute anesthesia, no surgical shock, localized analgesia to the area of the block, and minimal postoperative vomiting.” In the 1930s and 1940s, pediatric regional anesthesia did not receive significant press or popularity in the anesthesia literature, likely due to advancement in the pharmacology involved with general anesthesia, including tubocurarine, thiopentone, and cyclopropane.² By the 1960s, pediatric caudal epidural techniques were being described in both the literature and textbooks as a reliable method to provide surgical anesthesia.^3,4 The early history of regional anesthesia in infants and children dealt primarily with neuraxial techniques, including spinal and epidural anesthesia. Although first described in the 1980s, peripheral and truncal blockade in children has also become more commonplace within the past 10 years with the introduction of ultrasound and the development of pediatric-appropriate equipment.

Given these advancements, the last decade has witnessed an increased use of regional anesthesia in the perioperative period in infants and children of all ages. Although regional anesthetic techniques are used most commonly as an adjunct to general anesthesia to either supplement general anesthesia or to provide postoperative analgesia, many of these regional anesthetic techniques can also be used instead of general anesthesia in circumsTances where anatomic or physiologic alterations may make the conduct of general anesthesia more difficult or dangerous. Furthermore, with the recent information regarding apoptosis and an increased awareness regarding the potential neurotoxic effects of anesthetic agents on the developing brain, there has been a resurgence in interest in using spinal anesthesia for short surgical procedures such as herniorrhaphy in neonates and infants.⁵ Alternatively, as in the adult population, regional anesthetic techniques in conjunction with sedation is viewed as an equal alternative to general anesthesia in some centers. Regional anesthetic techniques may also be used during painful or invasive procedures in situations where the conduct of general anesthesia may not be readily possible, as a therapeutic modality to provide sympathetic blockade in patients with vascular insufficiency, and in the treatment of acute and chronic pain of various etiologies. Regardless of the situation, appropriate training, the correct equipment, and accurate placement are mandatory to ensure the success and safety of the technique.

In pediatric-aged patients, caudal epidural anesthesia remains the most frequently performed regional anesthetic technique.⁶ Although this technique is effective for lower abdominal and lower extremity procedure, other approaches are obviously necessary when the operative
procedure or pain process involves the upper extremity. For unilateral extremity procedures, there has been increased use of peripheral nerve blockade to allow for unilateral anesthesia and avoid the potential adverse effects of neuraxial techniques, including bilateral lower extremity motor blockade, urinary retention, and sympathectomy. The potential advantages of peripheral block are illustrated by two surveys of regional anesthetic techniques from the French Language Society of Paediatric Anaesthesiologists, commonly known as Association des Anesthesistes Reanimateurs Pediatriques d’Expression Francaise (ADARPEF).^7,8 In its first survey, central neuraxial blockade (mostly caudal epidural blockade) accounted for 60% of the 24,409 regional anesthetic techniques. There were 4,090 peripheral nerve blocks, 997 of which were placed in the upper extremity. No complications were noted related to the peripheral nerve blocks, whereas the complication rate related to caudal epidural block was 1.5%. These results prompted the authors to suggest that “the extremely low incidence of complications (zero in the study) after peripheral nerve blocks should encourage anesthesiologists to use them more often, when they are appropriate, in the place of a central block.” A follow-up study, published in 2012 from the ADARPEF, noted similar findings.⁸ The 12-month data collected from 47 institutions included 29,870 regional anesthetic techniques used in association with general anesthesia and 1,262 sole regional blocks. Central blocks accounted for 34% of all of the techniques as compared to 60% in the first survey. In children aged ≤3 years, the percentage of central blocks was similar to the peripheral ones (45% versus 55%). In older patients, peripheral blocks were four times more common than central techniques. The second survey also showed an increased occurrence of peripheral blockade of the face and trunk. Complications were rare, occurring in only 40 patients for an overall complication rate of 0.12%, and did not result in any sequelae. The complication rate was six times higher for central than for peripheral blocks. The authors continued to encourage the use of peripheral instead of central blocks, including caudal whenever appropriate.

The findings of the ADARPEF group and the safety of regional anesthesia have been echoed more recently with the report from the Pediatric Regional Anesthesia Network (PRAN).⁹ PRAN is a multi-institutional study focusing of the use and incidence of complications of pediatric regional anesthesia. A total of 14,917 regional blocks, performed on 13,725 patients, were accrued from April 1, 2007 through March 31, 2010. There were no deaths or complications with sequelae lasting greater than 3 months related to regional anesthesia. Single-injection blocks had fewer adverse events than continuous blocks, although the most frequent events (33% of all events) in the latter group were catheter-related problems. Ninety-five percent of blocks were placed while patients were anesthetized. Although single-injection caudal blocks remained the most frequently performed (40%), peripheral nerve blocks were also frequently used (35%), possibly driven by the widespread use of ultrasound (83% of upper extremity and 69% of lower extremity blocks). The conclusion stated that “regional anesthesia in children as commonly performed in the United States has a very low rate of complications, comparable to that seen in the large multicenter European studies.”⁸

The ongoing research regarding the potential neurotoxicity of general anesthetic agents on the developing brain has also prompted a further interest in regional anesthesia in the pediatric population. In the recent literature, gamma-aminobutyric acid antagonists and N-methyl-D-aspartate agonists have been shown to accelerate apoptosis in the immature brain, with concerns expressed regarding eventual neurocognitive outcomes.^{10, 11and 12} These concerns have led to a renewed interest in the use of regional anesthesia instead of general anesthesia or at least combining a regional anesthetic technique with general anesthesia as a means of limiting exposure to pro-apoptotic agents. Certainly, further investigation needs to be performed before any definitive conclusions can be drawn regarding these issues.

Ongoing advancements in technique and refinement of the available equipment have improved the applicability of regional anesthetic techniques in the pediatric population. The use of ultrasound-guided blockade has gained widespread applicability in the adult population. Given its ease of use, noninvasive modality, and potential to improve the success rate and decrease the incidence of adverse effects, ultrasound-guided regional anesthesia has increased in the pediatric population.^{13, 14and 15} Of the many differences between the practices of adult and pediatric regional anesthesia, the major one is that in the pediatric-aged patient, these techniques are performed in the anesthetized or deeply sedated patient.^9,16 This practice is well within the sTandard of care for infants and children and, as such, a means of ensuring correct placement of the needle is mandatory. This has been demonstrated in the more than 40,000 blocks reported in the publications of Giaufre and Polaner.^{7, 8and 9} The following chapter reviews basic information regarding the use of ultrasound to guide regional anesthesia procedures in infants and children, discusses some of the appropriate equipment needed for such a practice, and reviews issues related to local anesthetic agents in pediatric patients, including dosing regimens, test dosing to identify inadvertent intravascular injection, local anesthetic toxicity, and its treatment.