右美托咪定镇静下瑞芬太尼抑制气管插管反应半数有效效应室浓度的测定

Effect-site concentration of remifentanil required to prevent tracheal intubation response in 50% of patients sedated with dexmedetomidine

目的：测定右美托咪定镇静保留自主呼吸下非窥喉光棒内镜技术插管时所需瑞芬太尼的半数有效效应室浓度（EC50）。方法择期手术需全麻的女性患者，年龄18～60岁，身体质量指数（body mass index,BMI）（19～24）kg/m^2，ASA分级Ⅰ～Ⅱ级， Mallampati分级Ⅰ～Ⅱ级，入室后开放右肘正中静脉,静卧10分钟后开始静脉输注负荷剂量右美托咪定0.8μg/kg（10分钟泵完），后以0.5μg/（kg ＆#183; h）持续泵入，当脑电双频指数（bispectral index,BIS）值降至65～60时，靶控输注瑞芬太尼（Minto模型），达到预定效应室靶控浓度时，在其配合的状态下，利用非窥喉光棒内镜技术经口明视气管内插管。瑞芬太尼的效应室浓度按序贯法确定，相邻浓度之间的比值为1.1。瑞芬太尼效应室浓度从3.0ng/ml开始，入选样本从发生插管阳性反应的前一阴性反应病例开始计算，直至出现6个阴、阳性反应的交替波形。结果瑞芬太尼抑制非窥喉光棒内镜技术插管气管反应的EC503.43ng/ml，95%的可信区间是2.91～3.94ng/ml。结论在右美托咪定镇静保留自主呼吸下行非窥喉光棒内镜技术插管时所需瑞芬太尼的EC503.43ng/ml，95%的可信区间是2.91～3.94ng/ml。

Objective To determine the effect-site concentration of remifentanil required to prevent tracheal intubation response in 50% of patients sedated with dexmedetomidine. Method The female patients, ASA Ⅰor Ⅱ , aged 18 ~ 60yr, body mass index （19 ~ 24）kg/m^2, mallampati Ⅰ -Ⅱ , undergoing elective surgery with general anesthesia were enrolled in the study. After the median vein of the right elbow was opened, the patients lay in a supine position for 10min before the start of infusion of loading dose of0.8μg/kg dexmedetomidine （finished in 10min）, followed by a continuous infusion of 0.5μg/（kg.h） dexmedetomidine. When the bispectral index （BIS） fell to 65~60, remifentanil was administered using target-controlled infusion with the Minto model, and then the tracheal tube with wire was inserted through the mouth. Effect-site concentration of remifentanil was selected for each patient according to the Sequential Method. The ratio of two consecutive effect-site concentrations was 1.1.The experiment started from effect-site concentration ofremifentanil at 3.0ng/ml.The selected sample was counted from the case of negative response for tracheal intubation before the positive response one until six pairs of positive-negative crossovers were obtained. Result The ECs0 of remifentanil was 3.43ng/ml （95% confidence interval, 2.91 - 3.94 ng/ml）.Conelusion The effect-site concentration of remifentanil at 3.43ng/ml （95% confidence interval, 2.91 - 3.94 ng/ ml） can prevent tracheal intubation response in 50% of patients sedated with dexmedetomidine.