肥胖产妇分娩镇痛中罗哌卡因的半数有效浓度

Median effective concentration of ropivacaine in labor analgesia for obese parturient women

目的运用改良序贯法测定肥胖产妇分娩镇痛中罗哌卡因的半数有效浓度(EC_(50))。方法26例拟行分娩镇痛的产妇,BMI均≥30kg/m^(2)。罗哌卡因初始浓度为0.1%,若镇痛有效,则下一例降低罗哌卡因浓度;反之则增加浓度。罗哌卡因浓度梯度为0.01%,直至出现镇痛有效和无效交替波形成7个拐点终止研究。分娩镇痛有效标准:给予罗哌卡因首次剂量30min,产妇VAS疼痛评分≤3分。运用Probit回归分析计算肥胖产妇分娩镇痛中罗哌卡因的EC_(50)和95%有效浓度(EC_(95))及其对应95%CI。记录分娩镇痛前、镇痛后10min和30min时的VAS疼痛评分,记录皮肤瘙痒、产间发热、恶心呕吐和尿潴留等不良反应发生情况。结果肥胖产妇分娩镇痛中罗哌卡因的EC_(50)及其95%CI为0.064%(0.057%~0.070%),EC_(95)及其95%CI为0.076%(0.070%~0.106%)。1例产妇出现产间发热,所有产妇未出现皮肤瘙痒、恶心呕吐及尿潴留等不良反应。结论肥胖产妇单纯罗哌卡因分娩镇痛的EC_(50)为0.064%。

Objective To determine the median effective concentration(EC_(50)) of ropivacaine for labor analgesia in obese parturients using the modified sequential method.Methods Twenty-six obese parturients with BMI≥30 kg/m^(2) undergoing labor analgesia were selected.Ropivacaine was initially administered in a concentration of o.1%.If analgesia was effective,the next parturient received a lower concentration of ropivacaine,and if it was ineffective,the concentration was increased.This gradient of ropivacaine concentration was set at 0.01%.The study was terminated after the occurrence of seven alternating effective and ineffective analgesia responses.The criteria for effective labor analgesia were a VAS pain score<3 points within 30 minutes of administering the initial dose of ropivacaine.Probit regression analysis was used to calculate the EC_(50),EC_(95) and their corresponding 95%CI for ropivacaine in labor analgesia.VAS pain scores were recorded at the time points of before labor analgesia,10 minutes and 30 minutes after labor analgesia.Adverse reactions such as skin itching,postpartum fever,nausea,vomiting and urinary retention were recorded.Results The EC_(50) and its 95%CI of ropivacaine in labor analgesia for obese parturients were 0.064%(0.057%-0.070%).The EC_(95) and its 95%CI were 0.076%(0.070%-0.106%).One case of postpartum fever occurred,while no case of itching,nausea,vomiting or urinary retention was observed.Conclusion The EC_(50) of ropivacaine for labor analgesia in obese parturients was determined to be 0.064%.