全麻诱导时七氟醚ED_(50)值及咪唑安定对其影响

ED_(50) of sevoflurane during induction of general anesthesia and effect of midazolam on it

目的以脑电双频谱指数(BIS)60为指标,确定七氟醚全麻诱导半数有效量(ED50)及咪唑安定对其影响。方法全麻患者59例随机分为两组:Ⅰ组(31例)麻醉诱导吸入七氟醚,按序贯法给药;Ⅱ组(28例)七氟醚麻醉诱导前给予咪唑安定0.05mg/kg,同样按序贯法吸入七氟醚。记录患者意识消失时间围插管期MAP、HR、BIS。结果 BIS值达60时,Ⅰ组七氟醚的ED50为3.52%(95%的可信区间为3.46%～3.57%),明显高于Ⅱ组的2.61%(95%的可信区间为2.52%～2.70%)。Ⅰ组插管后MAP、HR显著高于插管前(P<0.01),Ⅱ组插管后循环稳定。Ⅱ组BIS值达60的七氟醚浓度、意识消失时间小于Ⅰ组(P<0.01)。结论七氟醚快速诱导时,BIS值达60插管后血压和心率仍有明显增加。加用咪唑安定有利于减少七氟醚吸入浓度和稳定血流动力学。

Objective To determine the median-effective dose（ED50）of sevoflurane induction under bispectral index （BIS） 60 and observe the effect of midazolam on it.Methods Fifty-nine patients of general anesthesia were randomly divided into two groups of Ⅰ induced with sevoflurane inhalation by up-and-down method and Ⅱ given midazolam 0.05 mg/kg before sevoflurane as in groupⅠ.MAP,HR,BIS and the time of losing consciousness were recorded during induction and intubation.Results At BIS 60,the value of ED50 was 3.52% with 95% confidence interval of 3.46%-3.57% in group Ⅰ,which was higher than 2.61% with 95% confidence interval of 2.52%-2.70% in group Ⅱ （P〈0.01）.MAP and HR were higher after intubation than those before in groupⅠ （P〈0.01）,which were stable in group Ⅱ with earlier loss of consciousness（P〈0.01）.ConclusionDuring induction with sevoflurane,MAP and HR are remarkably incresed at BIS 60.Additional use of midazolam before induction is helpful in reducing sevoflurane inhalation and stabilizing circulation during intubation.