剖宫产术患者蛛网膜下腔注射不同等比重局麻药的药效学

目的 探讨剖宫产术患者蛛网膜下腔注射不同等比重局麻药的药效学.方法 拟在脊椎-硬膜外联合阻滞下行剖宫产术患者96例,孕37～41周,ASA分级Ⅰ或Ⅱ级,体重50～85kg,随机分为3组(n=32):布比卡因组、左旋布比卡因组和罗哌卡因组分别于蛛网膜下腔注射等比重0.5%布比卡因、等比重0.5%左旋布比卡因和等比重0.5%罗哌卡因.采用序贯法进行试验,初始剂量为9 mg,相邻剂量比为0.9,麻醉有效,则下一例患者采用低一级剂量;麻醉无效,则下一例患者采用高一级剂量.麻醉有效的标准:注射局麻药后15 min内感觉阻滞平面达到T7或以上、术中无牵拉痛、注射局麻药后45 min内硬膜外不需要追加局麻药.计算3种局麻药麻醉的半数有效剂量(ED50)和95%有效剂量(ED95)及其95%可信区间(95%CI).结果 布比卡因麻醉有效的ED50(95%CI)、ED95(95%CI)分别为6.15(5.48～6.68)mg、7.62(6.91～11.82)mg;左旋布比卡因麻醉有效的ED50(95%CI)、ED95(95%CI)分别为8.06(7.46～8.62)mg、9.59(8.86～13.42)mg;罗哌卡因麻醉有效的ED50(95%CI)、ED95(95%CI)分别为10.55(9.73～11.49)mg、12.80(11.66～21.42)mg.布比卡因、左旋布比卡因和罗哌卡因的效价比为1.00:0.76:0.58.结论 剖宫产术患者蛛网膜下腔注射等比重布比卡因、左旋布比卡因和罗哌卡因麻醉有效的效价比为1.00∶0.76∶0.58.

Pharmacodynamics of different local anesthetics administered intrathecally for caesarean section

Objective To investigate tbe pharmacodynamics of different local anesthetics administered intrathecally for caesarean section. Methods Ninety-six parturients with singleton term pregnancies undergoing caesarean section under combined spinal-epidural anesthesia were enrolled in this study. The patients were randomly divided into 3 groups ( n = 32 each ) and received intrathecal (IT) 0.5 % bupivacaine, 0.5 %levobupivacaine and 0.5% ropivacaine respectively. The initial doses was 9 mg in all 3 groups. The ratio of two successive doses was 0.9. If the upper sensory block reached T7 or above and there was no need for additional dose in the 45 min after the initial dose, the IT analgesia was considered to be effective. The median effective dose ( ED50 ), the 95 % effective dose( ED95) and 95 % confidence interval (95 % CI )were calculated by Dixon. Results The ED50 and ED95 and 95%CI of bupivacaine were 6.15 (95%CI 5.48-6.68) mg and 7.62 (95%CI 6.91-11.82) mg; of levobupivacaine were 8.06 (95%CI 7.46-8.62) mg and 9.59 (95%CI 8.86-13.42) mg;of ropivacaine were 10.55 (95%CI 9.73-11.49) mg and 12.80 (95%CI 11.66-21.42) mg. The relative potency potency ratio between bupivacaine, levobupivacaine and rupivacaine is 1.00:0.76:0.58.