椎管内麻醉下使病人意识消失的异丙酚ED50

目的本研究拟通过序贯法测定胸段硬膜外麻醉或腰麻下使50％病人入睡的异丙酚的剂量（催眠ED50）。并监测复合麻醉下BIS值的变化，分析其能否反映镇静深度。方法20例行开胸手术的病人及30例行下腹部或下肢手术的病人。分别予2％利多卡因15ml行硬膜外麻醉和丁卡因（10mg）腰麻。以半数效量序贯法测定异丙酚的催眠ED50：将异丙酚的首次剂量等比分为五阶梯：0．56mg／kg，0．68mg／kg，0．84mg／kg，1．02mg／kg，1．25mg／kg。按序贯法给药。以呼之不应和睫毛反射消失作为入睡指标，并监测脑电双频谱指数（BIS）和病人的血流动力学指标。结果胸段硬膜外麻醉下异丙酚的催眠ED50：0．82mg／kg（95％置信区间：0．71mg／kg～0．94mg／kg）。腰麻下异丙酚的催眠ED50：0．8095mg／kg（95％置信区间为0．7295mg／kg～0．8974mg／kg）。异丙酚诱导后入睡和未睡病人BIS值相比P〈0．001，有统计学意义。结论序贯法计算半数效量简单有效。BIS值可以有效反映椎管内麻醉合用异丙酚的麻醉深度。

The hypnotic ED50 of propofol in patients undergoing epidural or spinal block

Objective To determine the dosage of propofol at which 50% of patients fall into unconsciousness(ED_(50))in the case of combining with thoracic epidural block or spinal block,using sequential experimental method.Methods 20 patients undergoing tho- racic surgery and 30 patients undergoing lower abdominal or extremity operations were included into the study.All the patients received 15 ml of 2% lidocaine epidurally or 10 mg hyperbaric decaine subarachnoidally.Propofol was then given intravenously with five differ- ent doses:0.56 mg/kg,0.68 mg/kg,0.84 mg/kg,1.02 mg/kg or 1.25 mg/kg.Blood pressure(BP),heart rate(HR)and bispec- tral index(BIS)were monitored during the study.The dosage of propofol was measured using sequential experimental method.The da- ta obtained were calculated to determine ED_(50)using weighted averaging method.The correlation between the dosage of propofol and BIS was analyzed with linear regression.Results The ED_(50)values of propofol combining with thoracic epidural block and with spinal block were 0.82 mg/kg(95% confidence intervals:0.71 mg/kg-0.94 mg/kg)and 0.8095 mg/kg(95% confidence intervals:0.7295 mg/kg-0.8974 mg/kg),respectively.The dosage of propofol was negatively correlated with BIS(r=-0.47,P=0.036 for epi- dural block and r=-0.434,P=0.019 for spinal block).Conclusion The findings of present study suggest that using sequential ex- perimental method to determine the ED_(50)level of propofol is simple and efficient,and that BIS is an effective index for monitoring depth of anesthesia in the situation of general anesthesia combining with epidural/spinal block.