半紧闭系统第二气体效应的研究

Second Gas Effect in Semi-closed System

目的与方法：采用自身对照，比较单独吸入异氟醚、安氟醚及复合５０％氧化亚氮吸入时的浓度变化，探讨第二气体效应的影响。结果：各对照组吸入浓度出现时间无显著差异，复合吸入组呼气末浓度仅在前５ｍｉｎ左右高于单独吸入组。异氟醚、安氟醚的吸－呼浓度差，仅在最初的０．５～１ｍｉｎ，复合吸入组略高于单独吸入组。结论：异氟醚、安氟醚与５０％氧化亚氮混合吸入时，第二气体效应并不明显，表明第二气体效应反映在各种组合的麻醉混合气中并不一致。

biective and Methods;To invastigate the influence of second gas effect on the uptake of inhalation agent,the inspired and expired concentrations of isoflurane and enflurane were measured with or without 50% N_2O.Results:The expired concentrations of isoflurane or enflurane were higher with 50% N2O than that without it at the first 5min.The differences between inspired and expired concentration of isofluraneor enfluraneN_2O groups were also higher than that of isofluraneor enfluraneO2 groups at the first 051min.Conclusion:There is no significant second gas effect during inspiration of either isofluraneN2O mixture or enfluraneN2O mixtrue under our experimental condition。