右美托咪定抑制老年患者气管插管反应半数有效剂量的序贯研究

摘要

目的：探讨右美托咪定抑制老年患者气管插管反应的半数有效剂量（ ED50）。方法择期全麻手术患者47例，按照年龄分为A组（60～69岁）23例及B组（70～79岁）24例。右美托咪定的初始剂量为0．3μg／kg，按剂量－效应序贯法调节下一例患者剂量，插管反应阴性－阳性出现7次交叉时试验结束。采用概率分析法计算右美托咪定抑制气管插管反应的ED50和ED95，监测两组Narcotrend值及血流动力学变化情况。结果 A组共20例患者完成研究，右美托咪定抑制气管插管反应的ED50、ED95分别为0．314μg／kg、0．369μg／kg。 B组共23例患者完成研究，右美托咪定抑制气管插管反应的ED50、ED95分别为0．256μg／kg、0．339μg／kg。两组患者在全麻诱导气管插管期Narcotrend值为40～60，血压升高出现在插管后30 s至3 min，血压下降最明显出现在插管前即刻。两组患者血管活性药物使用情况比较，差异无统计学意义（P＞0．05）。结论右美托咪定抑制60～69岁、70～79岁患者气管插管反应的ED50分别为0．314μg／kg、0．256μg／kg。%Objective To explore the median effective dose(ED50 ) of dexmedetomidine for inhibiting response to endotracheal intubation in elderly patients.Methods Forty-seven elderly patients undergoing selective surgery with general anesthesia were divided into Group A (aged 60 to 69 years) and Group B(aged 70 to 79 years) according to their ages.The initial dose of dexmedetomidine was 0.3 μg/kg,and the dose of sequent patients was predetermined using a modified up-and-down method of Dixon .The experiment was terminated when the negative response to endotracheal intubation was crossed with the positive response for 7 times.Probability analysis method was used to calculate the ED50 and 95% effective dose ( ED95 ) of dexmedetomidine for inhibiting response to endotracheal intubation .The changes of Narcotrend values and hemodynamics were monitored .Results In Group A,20 patients finished the experiment,and the ED50 and ED95 of dexmedetomidine for inhibiting response to endotracheal intubation were 0.314μg/kg and 0.369μg/kg rspectively.In Group B,23 patients finished the experiment,and the ED50 and ED95 of dexmedetomidine for inhibiting response to endotracheal intubation were 0.256μg/kg and 0.339μg/kg respectively.During the endotracheal intubation period of general anesthesia ,the Narcotrend values of two groups ranged from 40 to 60,blood pressures increased significantly 30 seconds to 3 minutes after intubation and decreased most obviously in the immediate intubation .There were no significant differences in the use of vasoactive drugs between two groups(P>0.05).Conclusion The ED50 of dexmedetomidine for inhibiting response to endotracheal intubation in patients aged 60-69 years and 70-79 years are 0.314μg/kg and 0.256μg/kg respectively.