神经刺激仪引导下锁骨上臂丛神经阻滞罗哌卡因半数有效浓度的研究

目的：测定锁骨上臂丛神经阻滞罗哌卡因的半数有效浓度（half-effective concentration,EC50）。方法：选择ASAⅠ－Ⅱ级上肢手术患者50例,采用神经刺激仪引导定位锁骨上臂丛神经阻滞。30 m in内评定麻醉效果,以VAS评分≤4分作为麻醉阳性（有效）指标。罗哌卡因总量30 m l,初始浓度为0.30%,其后浓度采用双盲根据前一患者的麻醉效果序贯递增或递减,间隔浓度为0.025%。通过SPSS13.0统计软件,prob it回归确定EC50及95%可信区间。结果：在本研究条件下罗哌卡因用于锁骨上臂丛神经阻滞的EC50为0.295%,95%可信区间为0.276%－0.316%。结论：罗哌卡因用于神经刺激仪引导下的锁骨上臂丛阻滞的EC50为0.295%。术中辅助用药可能对其EC50的影响尚需进一步研究。

Half-effective concentration of ropivacaine in nerve stimulator-guided supraclavicular brachial nerve block

Objective： To determine the half-effective concentration（EC50） of ropivacaine in nerve stimulator-guided supraclavicular brachial nerve block.Methods： Surpaclavicular brachial nerve block guided by nerve stimulator was performed in 50 patients with ASAⅠtoⅡ requiring scheduled elective upper-limb surgery.Each participant received 30 ml bolus of ropivacaine,and the concentration of ropivacaine was given by the response of the previous patient to a higher or lower concentration using double-blind,up-and-down sequential allocation.The initial concentration of ropivacaine was 0.30%,and the variety of two close concentrations was 0.025%.The anesthetic efficacy was assessed with visual analogue scale（VAS） within 30 min after anesthesia,and the effectiveness was defined as having a VAS≤4.The EC50 was obtained by probit analysis.Results： Among the 50 patients,one was excluded from the study because of uncertain anesthetic efficacy.The EC50 of ropivacaine in nerve stimulator-guided supraclavicular brachial nerve block was 0.295%,and 95% confidence interval was 0.276-0.316%.Conclusion： The EC50 of ropivacaine in nerve stimulator-guided supraclavicular brachial nerve block is 0.295%.The possible effects of assisted drug during operation needed further study.