【摘要】 目的 测定自然分娩第一产程时硬膜外罗哌卡因的局部镇痛的半数有效浓度(effeetiveconcentrations in 50％ patient,EC50)。方法 选择33例产前无服用镇痛催眠药史的足月初产妇(ASA Ⅰ~Ⅱ级),宫口开张2～3cm时行硬膜外穿刺置管,注入20ml罗哌卡因溶液。以上一产妇的结果,根据双盲、序贯方法确定所用的罗哌卡因药液浓度,视觉模拟评分(VAS)小于3分时为有效。初始的罗哌卡因浓度定为0.15％。结果 共3例产妇因结果可疑而被排除,余30例产妇结果呈有效或无效而进入分析。结果显示:第一产程时硬膜外罗哌卡因镇痛的EC50是0.063％(95％可信区间为:0.05972％～0.06699％)。结论 利用序贯试验方法测定自然分娩时硬膜外罗哌卡因镇痛的EC50是0.063％。更多还原

【Abstract】 Objective The aim of this study was to determine the effective concentration of epidural ropivacaine for analgesia in 50% of parturients (EC50) in the first stage of labor. Methods Thirty-three ASA Ⅰ -　Ⅱ nulliparous women with 2-3 cm cervical dilatation who requested epidural analgesia were enrolled in the study. Epidural catheter was placed at L3-4 and advanced for 3-4 cm in the epidural space in a cephalad direction. 20 ml of ropivacaine solution of which the EC50 was being tested was given through the catheter into epidural space. The EC50 was determined by up-and-down sequential experiment. The initial concentration of the epidural ropivacaine being tested was decided to be 0.15% . If effective the next parturient received ropivacaine of a lower concentration; if ineffective the concentration of ropivacaine was increased in the next parturient. Each time the concentration of epidural ropivacaine increased/decreased by 0.01% . Analgesia was assessed by VAS score (1-10) . If VAS score was less than 3 within 30 min of ropivacaine administration, analgesia was defined as effective.Results Among the 33 parturients enrolled, three were excluded from the study because of uncertain analgesic efficacy. The results showed that the EC50 of epidural ropivacaine for analgesia in the first stage of labor was 0.063% [95% confidence interval (CI) was 0.05972%-0.06688%] .Conclusion The EC50 epidural ropivacaine for analgesia in the first stage of labor is 0.063 % determined by sequential experiment method.更多还原