SPREAD OF LOCAL-ANESTHETIC INTO THE EPIDURAL CAUDAL SPACE FOR 2 RATESOF INJECTION IN CHILDREN

Background and Objectives. The optimal rate of injection of local anes thetic in pediatric caudal blocks has not been determined. The purpose of this study was to determine the influence of two rates of injectio n on the level of analgesia in children. Methods. The patients, 79 chi ldren, American Society of Anesthesiologists class I, who were schedul ed for minor surgery, were allocated to three groups according to age: group 1, 0-12 months; group 2, 13-36 months; and group 3, 37-72 month s. Each ago group was further divided randomly into two subgroups acco rding to rate of injection: subgroup A received 1 mL/kg of 0.25% bupiv acaine with 1:200,000 epinephrine at a rate of 1 mL/s, and subgroup B received the same dose at a slower rate of 1 mt per 10 s. Level of ana lgesia was assessed by loss of sensation to skin pinching. Age, weight , height, time of surgery, onset, and level of analgesia and complicat ions were recorded. Results. For the faster rate, significant differen ces in level of analgesia were found between groups 1 and 2; the group s were not significantly different for the slower rare, however. The m edian level in patients 12 months and under was two dermatomes above t hat of patients older than 12 months at both rates. The levels for eac h rate (subgroups A and B) were not significantly different in any age group. The time needed to reach the highest level became progressivel y longer with age (from group 1 to 3), and differences were significan t at both rates. Conclusion. Level of analgesia is not affected by the rate injection of 0.25% bupivacaine into the epidural caudal space in children. The time needed to reach the highest level increases as the child ages.