吸入麻醉第二气体效应存在条件的定量分析

Quantitative analysis on the conditions adequate for the existence of the second gas effect

目的对吸入麻醉药的第二气体效应的存在条件做出定量分析。方法在回顾性研究的基础上,用热力学的宏观理论和数学的定量分析方法,从3个层面对第二气体效应进行理论论证。结果第二气体的摄取率b和其他混合气体的平均摄取率b0(=apx+cp2/px+pz)相比,若b=b0,则不存在第二气体效应;若b<b0,则存在第二气体效应;若b>b0,存在反第二气体效应。结论第二气体效应的存在是有条件的,第二气体与其他混合气体的摄取率的相对大小是关键因素。

Objective To make a quantitative analysis on the existence of the second gas effect. Methods Under the guidance of the macroscopic theories in thermodynamics and quantitative analysis in mathematics,the second gas effect was discussed at three aspects： the conditions for the existence of the second gas effect,those for the non-existence of the second gas effect and those for the existence of the reverse second gas effect. Results When the uptake rate of the second gas was equal to the average uptake rate of other gas mixtures,the second gas effect did not exist. When the former was less than the latter,the second gas effect existed. When the former was greater than the latter,the reverse second gas effect existed. Conclusion The existence of the second gas effect is not absolute but conditional. The key factor is the relative size of the uptake rate of the second gas and the average uptake rate of other gas mixtures in alveolar.