BCD序贯法测定布比卡因蛛网膜下腔阻滞肛管术的半数有效剂量研究

Half effective dose(ED50)of intrathecal bupivacaine for anal survery:a biased coin design study

目的肛管术中等比重布比卡因的最小剂量鲜有报道。文中旨在采用抛偏倚硬币设计(BCD)序贯法计算等比重布比卡因蛛网膜下腔阻滞用于肛管手术的半数有效剂量(ED50)。方法选择2019年4月至2020年4月江苏省中西医结合医院肛肠科40例肛周手术患者。按BCD序贯试验法设定0.5%等比重布比卡因剂量,起始剂量1 mg,根据针刺肛周有无疼痛进行下一例患者剂量调整,间隔0.5 mg。用Probit回归法计算ED50,评估痛觉阻滞平面和下肢运动阻滞情况,统计不良反应发生情况。结果0.5%等比重布比卡因蛛网膜下腔阻滞用于肛管手术的ED50为2.08 mg(95%CI 0.96~2.41 mg)。痛觉阻滞平面上界中位数4.5(2,5),改良Bromage评分0级39例(97.33%),1级1例(2.63%)。所有患者未出现低血压、心动过缓、呼吸抑制和恶心呕吐,4例(10%)患者主诉下腹部牵拉不适。结论BCD序贯法测定0.5%等比重布比卡因蛛网膜下腔阻滞用于肛管手术的ED50为2.08 mg(95%CI 0.96~2.41 mg),值得推广。

Objective The reports of the minimum dose of intrathecalisobaric bupovacaine for anal operation are limited.To determine the half effective dose(ED50)of intrathecal isobaric bupivacaine for anal surgery using the biased coin design(BCD).Methods From April 2019 to April 2020,40 patients underwent anal surgeries were recruited in the Department of Proctology in Jiangsu Province Hospital on Integration of Chinese and Western Medicine.Using the BCD technique,0.5%isobaric bupivacaine with a low starting dose of 1.0 mg were administered,and then adjusted with 0.5 mg according to the pain caused by acupuncture around the anusarea.If the desired effect(loss of pinprick pain)was not observed,the next patient in the assigned group received next higher dose of propofol in predetermined increments(0.5 mg)from the previous dose.If the desired effect was observed,the next patient in the same assigned group was randomized with a 0.95 probability to receive the same dose or a 0.05 probability to receive the next lower dose(also in 0.5 mg decrements).The ED50 was estimated by Probit Analysis.The sensory block and lower extremity motor block were evaluated,and the incidence of adverse reactions was statistically analyzed.Results The ED50 for 0.5%isobaric bupivacaine was 2.08 mg(95%confidence interval:0.96 to 2.41 mg).The median level of pain block was L5 segment(the highest segment level is at L1,the lowest segment level is at S1).The improved Bromage score was 0 in 39 patients(97.33%),and 1 score in 1 patient(2.63%).The discomfort of abdominal distension was found in 4 cases(10%),while hypotension,bradycardia,respiratory depression,nausea and vomiting were not found in all patients.Conclusion The ED50 of 0.5%isobaric bupivacaine for anal surgery was 2.08 mg(95%confidence interval:0.96 to 2.41 mg)using the biased coin design(BCD)is recommended.