靶控输注瑞芬太尼用于老年患者全麻苏醒期平稳拔管的半数有效剂量

Median effective concentration of remifentanil on target-controlled infusion for smooth emergence from aneasthesia and tracheal extubation in elderly patients

摘要:

目的：确定靶控输注瑞芬太尼用于老年患者全凭静脉麻醉（total intravenous aneasthesia，TIVA）后苏醒期安全平稳拔管的半数有效剂量。方法：择期全麻下行颌骨囊肿手术的老年女性患者24例，ASA Ⅰ～Ⅱ级，采用Dixon序贯法进行试验，开始缝合伤口时第1例患者以效应室靶浓度1 ng/ml输注瑞芬太尼，若拔管不平稳，则下一位预设靶浓度增加0.5 ng/ml。若拔管平稳，下一位预设靶浓度减少0.5 ng/ml。通过Dixon法计算瑞芬太尼用于平稳拔管的半数有效剂量（median effective concentration，EC50），利用logistic回归模型进行概率单位转换，分析瑞芬太尼EC50及其95%可信区间。比较平稳拔管组与不平稳拔管组平均动脉压和心率。结果：采用Dixon序贯法算出瑞芬太尼用于老年患者术后平稳拔管的EC50 0.94 ng/ml，概率单位换算法计算EC500.99 ng/ml（95%CI=0.52 ~1.51 ng/ml）。拔管期间，平稳拔管组平均动脉压、心率明显低于不平稳拔管组（P<0.05）。结论：靶控输注0.94 ng/ml瑞芬太尼可以减少50%的老年患者拔管相关的咳嗽反应，抑制苏醒期心血管反应，不导致全麻苏醒延迟，确保了苏醒期的平稳拔管。

Abstract:

Objective：To determine the median effective concentration of remifentanil on targeted-controlled infusion（TCI） for smooth emergency from total intravenous aneasthesia and tracheal intubation in elderly patients. Methods：Twenty-four ASA Ⅰ-Ⅱ grade fe－male elderly patients undergoing elective jaw cyst surgery were enrolled in this study. Median effective concentration（EC50） was de－termined by Dixon’s up-and-down method. During skin suture，effect-site TCI of remifentanil was titrated to initial concentration of 1 ng/ml for the first patient. If the extubation was defined as smooth extubation，the predetermined concentration for the subsequent patient was decreased by 0.5 ng/ml. If it was considered failed smooth extubation，the predetermined concentration was increased by 0.5 ng/ml for the next patient time. The EC50 of remifentanil was calculated by the Dixon’s up-and-down method and the EC50 and 95％ confidence interval（CI） were analyzed using the probit teat in a logistic regression model. Mean arterial pressure（MAP） and heart rate（HR） were compared in patients with smooth extubation and without smooth extubation. Results：The EC50 of remifentanil for smooth emergency from aneasthesia and tracheal intubation in elderly patients was 0.94 ng/ml by the Dixon’s up-and-down method，the EC50 and 95%CI of remifentanil was 0.99 ng/ml（95%CI 0.52 ng/ml-1.51 ng/ml）by probit analysis respectively． MAP and HR were lower in patients with smooth extubation than in those with failed smooth extubation during tracheal extubation（P<0.05）. Conclusion：Maintaining a remifentanil infusion at the optimal concentration of 0.94 ng/ml can suppress coughing associated with tra－cheal extubation and haemodynamic changes，almost without significantly delaying recovery from anaesthesia and thereby targeting smooth extubation for 50% of the elderly patients.