摘要目的 比较瑞芬太尼不同静脉输注速率对异丙酚抑制小儿喉罩置入反应半数有效血浆靶浓度(EC50)的影响,探讨瑞芬太尼用于纤维支气管镜检术麻醉时适宜的静脉输注速率.方法 择期行纤维支气管镜检术小儿84例,年龄7月～3岁,ASA分级Ⅰ或Ⅱ级,采用随机数字表法,将小儿分为3组(n=28):生理盐水对照组(C组)和静脉输注瑞芬太尼3或5 ng·kg-1·min-1组(R1组或R2组).喉罩置入反应定义为喉罩置入可诱发肢体和或呛咳反应.采用序贯法确定异丙酚血浆靶浓度:C组、R1组或R2组异丙酚初始靶浓度分别为5.2、4.8或4.4 μg/ml,相邻浓度差值为0.2 μg/ml,喉罩置入反应阴性则下一例采用低一级浓度,反应阳性则下一例采用高一级浓度.用概率单位法确定异丙酚EC50及其95％可信区间(CI).结果 C组异丙酚EC50(95％ CI)为5.03(4.92～ 5.12) μg/ml,R1组为4.71(4.58 ～ 4.84) μg/ml,R2组为4.46(4.20 ～ 4.94) μg/ml.与C组相比,R1组异丙酚EC50差异无统计学意义(P＞0.05),而R2组EC50降低,且也低于R1组(P＜0.05).结论 瑞芬太尼复合异丙酚麻醉用于小儿纤维支气管镜检术时,其静脉输注速率应不低于5 ng·kg-1·min-1.

abstractsObjective To compare the effects of remifentanil infused at different rates on median effective target plasma concentration (EC50) of propofol inhibiting responses to laryngeal mask airway (LMA) insertion and determine the optimum infusion rate of remifentanil when used for fiberoptic bronchoscopy in pediatric patients.Methods Eighty-four ASA Ⅰ or Ⅱ pediatric patients,aged 7 months-3 years,scheduled for elective fiberoptic bronchoscopy,were randomly assigned into 3 groups (n =28 each):normal saline group (group C),remifentanil infused at 3 ng· kg-1 ·min-1 group (group R1) and remifentanil infused at 5 ng· kg-1 · min-1 group (group R2).Responses to LMA insertion were defined as body movement and/or bucking during insertion.The initial target plasma concentrations of propofol were 5.2,4.8 and 4.4 μg/ml in groups C,R1 and R2,respectively.The target plasma concentration of propofol was determined by up-and-down sequential allocation.Each time the target plasma concentration increased/decreased by 0.2μg/ml.EC50 and 95 ％ confidence interval of propofol blunting responses to LMA insertion were determined by probit method.Results EC50 (95 ％ confidence interval) of propofol was 5.03 (4.92-5.12) μg/ml,4.71 (4.58-4.84) μg/rnl and 4.46 (4.20-4.94) μg/ml in groups C,R1 and R2,respectively.There was no significant difference in EC50 of propofol between groups R1 and C (P ＞ 0.05).EC50 of propofol was significantly lower in group R2 than in groups C and R1 (P ＜ 0.05).Conclusion The infusion rate of remifentanil should not be lower than 5 ng· kg-1· min-1 when combined with propofol in pediatric patients undergoing fiberoptic bronchoscopy.