羟考酮对老年患者硬膜外阻滞时罗哌卡因半数有效浓度的影响

Effects of oxycodone on median effective concentration of epidural ropivacaine in elderly patients

目的研究羟考酮对老年患者大隐静脉高位结扎剥脱术硬膜外阻滞时罗哌卡因半数有效浓度(EC50)的影响。方法采用随机、双盲、前瞻性研究。选择硬膜外麻醉下择期行大隐静脉高位结扎剥脱手术老年患者141例,随机均分为罗哌卡因复合低剂量羟考酮组(A组),罗哌卡因复合高剂量羟考酮组(B组),单用罗哌卡因组(C组)。第一例患者的罗哌卡因给药浓度C组为0.51%,A组和B组均为0.46%且分别复合羟考酮2.5mg和5 mg。以序贯法调整罗哌卡因浓度,相邻浓度比值为0.9,随后的浓度由同一组中先前患者的反应(L1-L5平面双侧感觉阻滞)来确定。记录生命体征、感觉阻滞起效时间以及不良反应发生情况。应用Dixon法计算罗哌卡因EC50及其95%置信区间(95%CI)。结果共完成139例,C组45例,A组和B组各47例。3组手术时间、运动阻滞Bromage评分和硬膜外给药后各观察时点的心率、平均动脉压比较均无显著差异(P> 0.05)。A组罗哌卡因EC50为0.399%(95%CI:0.371%-0.430%),B组为0.396%(0.355%-0.441%),C组为0.487%(95%CI:0.371%-0.430%),A组和B组罗哌卡因EC50低于C组(P <0.01),A组和B组间无显著差异(P> 0.05)。3组均无严重不良反应发生。结论羟考酮复合罗哌卡因硬膜外麻醉用于老年患者大隐静脉高位结扎剥脱术时,可降低罗哌卡因的EC50,羟考酮推荐剂量为2.5 mg。

AIM To study the effects of oxycodone on the median effective concentration(EC50) of epidural ropivacaine in elderly patients undergoing high ligation and stripping of great saphenous vein surgery. METHODS This was a prospective randomized double-blinded study. One hundred and forty-one elderly patients scheduled for high ligation and stripping of great saphenous vein surgery under epidural anesthesia were randomly divided into ropivacaine combined with low-dose oxycodone group(group A), ropivacaine combined with high-dose oxycodone group(group B), and ropivacaine group(group C). The concentration of ropivacaine was 0.51% for first patient in the group C, and 0.46% in the group A and group B with combination of oxycodone 2.5 mg and 5 mg respectively. The concentration of ropivacaine was adjusted by using the up-and-down sequential methods, with the ratio of 0.9 between the two successive concentrations. The subsequent concentration was determined by the response of previous patients in the same group(bilateral sensory block at L1-L5 level). The vital signs, onset time of sensory block, and adverse reaction were recorded. EC50 and 95% confidence interval(95% CI) of ropivacaine was analyzed by using Dixon method. RESULTS A total of 139 cases were completed, 45 cases in the group C, 47 cases in the group A and group B respectively. There was no significant difference in operation time, Bromage score of motor block examination, heart rate and mean artery pressure at each observation time point after epidural administration among the three groups(P > 0.05). The EC50 of ropivacaine was 0.399%(95% CI: 0.371% to 0.430%) in the group A, 0.396%(0.355% to 0.441%) in the group B, and 0.487%(95% CI: 0.371% to 0.430%) in the group C. The EC50 of ropivacaine in the group A and B was lower than that in the group C(P < 0.01). There was no significant difference between group A and group B(P > 0.05). No serious adverse reactions occurred in the three groups. CONCLUSION Oxycodone combined with ropivacaine epidural anesthesia can reduce the EC50 of ropivacaine in elderly patients with high ligation and stripping of great saphenous vein. The recommended dose of oxycodone is 2.5 mg.