喷他佐辛复合异丙酚用于老年患者胃镜检查术时的适宜剂量

Optimum dose of pentazocine when combined with propofol for gastroscopy in elderly patients

目的 确定喷他佐辛复合异丙酚用于老年患者胃镜检查术时的适宜剂量.方法 择期全麻下行胃镜检查术老年患者140例,年龄65～75岁,ASA分级Ⅰ或Ⅱ级,采用随机数字表法分为Ⅰ组-Ⅳ组,每组35例.置入胃镜前Ⅱ组-Ⅳ组分别静脉注射喷他佐辛0.2、0.4和0.8 mg/kg,Ⅰ组给予等容量生理盐水,随后靶控输注异丙酚,初始血浆靶浓度设为3.5μg/nl,采用序贯法进行试验,待效应室浓度与血浆浓度达平衡后5 min时行胃镜检查术,如发生阳性发应,则下一例患者异丙酚升高1个浓度梯度,反之降低1个浓度梯度,浓度梯度为0.3μg/ml,发生阳性反应的标准为胃镜检查术过程中出现明显体动和/或呛咳.采用概率单位法计算靶控输注异丙酚抑制胃镜检查术反应的半数有效浓度（EC50）及其95％可信区间（95％ CI）.记录呼吸抑制和低血压的发生情况.结果 Ⅰ组-Ⅳ组靶控输注异丙酚抑制胃镜检查术反应的EC50及其95％ CI分别为2.82（2.63～3.02） μg/ml、2.78（2.58～2.97）μg/ml、2.16（2.00～2.32）μg/ml和2.03（1.88 ～ 2.19） μg/ml.与Ⅰ组比较,Ⅲ组和Ⅳ组EC50降低,Ⅳ组呼吸抑制发生率升高（P＜0.05）.结论 喷他佐辛复合异丙酚用于老年患者胃镜检查术时的适宜剂量为0.4 mg/kg.

Objective To determine the optimum dose of pentazocine when combined with propofol for gastroscopy in elderly patients.Methods One hundred and forty ASA physical status Ⅰ or Ⅱ patients,aged 6575 yr,scheduled for elective gastroscopy under general anesthesia,were randomly assigned into Ⅰ-Ⅳ groups （n =35 each） using a random number table.Before insertion of the gastroscope,pentazocine 0.2,0.4 and 0.8 mg/kg were injected intravenously in Ⅱ-Ⅳ groups,respectively,while the equal volume of normal saline was given in Ⅰ group.Propofol was then administered by target-controlled infusion （TCI）.The half-effective concentration （EC50 of propofol was determined by up-and-down sequential trial.The target plasma concentration （Cp） was set at 3.5 μg/ml in the first patient.Gastroscopy was performed at 5 min after the target effect-site and plasma concentrations were balanced.The response to gastroscopy was defined as positive when body movement and/or bucking occurred during gastroscopy.Each time the Cp increased/decreased by 0.3 μg/ml in the next patient depending on whether or not the response to gastroscopy was positive.EC50 and 95 % confidence interval of propofol TCI inhibiting the response to gastroscopy were calculated using Probit analysis.The development of respiratory depression and hypotension was observed.Results EC50 （95 % confidence interval） of propofol TCI inhibiting the response to gastroscopy was 2.82 （2.63-3.02） μg/ml,2.78 （2.58-2.97） μg/ml,2.16 （2.00-2.32） μg/ml and 2.03 （1.88-2.19） μg/ml in Ⅰ-Ⅳ groups,respectively.Compared with group Ⅰ,EC50 was significantly decreased in Ⅲ and Ⅳ groups,and the incidence of respiratory depression was increased in Ⅳ group （P 〈 0.05）.Conclusion The optimum dose of pentazocine when combined with propofol is 0.4 mg/kg for gastroscopy in elderly patients.