罗哌卡因在幼儿尿道下裂成形术中的半数有效浓度测定

EC_(50) of ropivacaine for epidural anesthesia in hypospadias repair in children

目的:测定罗哌卡因在硬膜外麻醉下行幼儿尿道下裂成形术的半数有效浓度(effective concentration in50%pediatric congenital hypospadias angioplasty,EC50)。方法:选择硬膜外麻醉下行尿道下裂修复术的幼儿23例,年龄12～36个月,根据序贯试验的方法,硬膜外罗哌卡因初始浓度为0.4%,总剂量为1～1.5mL/kg,如镇痛完善,下一幼儿则把罗哌卡因浓度降低一个阶梯;如镇痛不完善,能用1.2%利多卡因改善则下一幼儿把罗哌卡因浓度提高一个阶梯;如镇痛不完善,不能用1.2%利多卡因改善,下一幼儿继续使用该浓度。罗哌卡因的浓度视前一幼儿麻醉效果而序贯地按等比级数1.4递增或递减配置。结果:共3例幼儿麻醉效果可疑而被排除,余20例呈有效或无效而进入分析。罗哌卡因在幼儿硬膜外麻醉EC50为0.168%,其95%的置信区间是0.163%～0.175%。结论:利用序贯试验方法测得罗哌卡因在小儿硬膜外麻醉下行尿道下裂成形术的EC50为0.168%。

Objective To determine EC50 of ropivacaine for epidural anesthesia in hypospadias repair in children. Methods Sequential trial was conducted in 23 children aged 12 to 36 months scheduled for hypospadias repair under epidural anesthesia. The initial concentration of ropivacaine was 0.4%, with a total dose of 1 - 1.5 mL/ kg. If the efficacy of analgesia was ideal, a lower concentration of ropivacaine was administered to the next child ; if not, but analgesia was improved by lidocaine of 1.2%, the next child received ropivacaine of a higher concentration. The concentration of ropivacaine would not changed if analgesia was not ideal and not improved by lidocaine. The concentration was increased or decreased sequentially in a ratio of 1.4 based on the analgetic effect on the prior child. Results Among the 23 children, three were excluded from this study because of uncertain efficacy. The results showed that EC50 of ropivacaine for epidural anesthesia in the childaren was 0.168% （95% CI 0.163% ~ 0.175%）. Conclusions EC50 of ropivacaine for epidural anesthesia in hypospadias repair in children is 0.168% on the sequential trial.