复合右美托咪定时梗阻性黄疸患者依托咪酯抑制气管插管反应的半数有效剂量

Dexmedetomidine ; Jaundice, obstructive ; Etomidate ; Dose-response relation- ship, drugMedian effective dose of etomidate inhibiting responses to endotracheal intubation when combined with dexmedetomidine in patients with obstructive jaundice

目的确定复合右美托咪定时梗阻性黄疸患者依托咪酯抑制气管插管反应的半数有效剂量（ED50）。方法择期全麻手术的梗阻性黄疸患者，年龄45～63岁，体重指数18～30kg／m^2，ASA分级Ⅱ或Ⅲ级。采用随机数字表法分为对照组（c组）和右美托咪定组（D组），麻醉诱导前15min，C组静脉输注生理盐水0．1ml／kg，D组静脉输注右美托咪定0．4μg／kg。麻醉诱导依次给予咪达唑仑0．05mg／kg、芬太尼4μg／kg、依托咪酯、顺苯磺酸阿曲库铵0．15mg／kg。采用序贯法进行试验，第1例患者静脉注射依托咪酯0．2mg／kg，气管插管后3min内MAP和／或HR升高幅度超过基础值20％，下一例患者采用高一级剂量，否则采用低一级剂量，相邻剂量比为1．1。记录各组有效／无效例数，采用Probit法计算依托咪酯抑制气管插管反应的ED50及其95％可信区间。结果C组依托咪酯抑制气管插管反应的ED，。及其95％可信区间为0．185（0．162～0．201）mg／kg，D组依托咪酯抑制气管插管反应的ED50及其95％可信区间为0．129（0．093～0．143）mg／kg，差异有统计学意义（P〈0．05）。结论复合右美托咪定时梗阻性黄疸患者依托咪酯抑制气管插管反应的ED50为0．129mg／kg。

Objective To determine the median effective dose （EDso） of etomidate inhibiting responses to endotracheal intubation when combined with dexmedetomidine in the patients with obstructive jaundice. Methods American Society of Anesthesiologists physical status II or BI patients with obstructive jaundice, aged 45-63 yr, with body mass index of 18-30 kg/m^2, scheduled for elective operations under general anesthesia, were divided into control group （group C） and dexmedetomidine group （group D） using a random number table. At 15 min before induction of anesthesia, normal saline 0. 1 ml/kg was infused intravenously in group C, and dexmedetomidine O. 4 ~g/kg was infused intravenously in group D. Anesthesia was induced with midazolam 0.05 mg/kg, fentanyl 4 txg/kg, etomidate and cisatracurium 0. 15 mg/kg. The ED50 of etomidate was determined using Dixon＇s up-and-down method. Etomidate was injected intravenously at the initial dose of 0.2 mg/kg in the first patient in each group. Each time the dose in- creased/decreased in the next patient according to whether or not the increase in mean arterial pressure and/ or heart rate i〉 20% of the baseline value within 3 min after endotracheal intubation. The ratio between the two successive doses was 1.1. The number of patients in whom inhibition was effective or ineffective was recorded, and the ED50 and 95% confidence interval of etomidate inhibiting responses to intubation were calculated using Probit analysis. Results The ED50 （95% confidence interval） of etomidate inhibiting responses to intubation was 0. 185 （0. 162-0. 201） mg/kg in group C, the ED50 （95% confidence interval） of etomidate inhibiting responses to intubation was 0. 129 （0. 093-0. 143） mg/kg in group D, and there was significant difference between the two groups （P〈0. 05）. Conclusion When combined with dexme- detomidine, the ED50 of etomidate inhibiting responses to endotracheal intubation is 0. 129 mg/kg in the patients with obstructive jaundice.