Munday I T, Ward P M, Foden N D, Jones R M, Van Pelt F N, Kenna J G
Academic Department of Anaesthetics, St Mary's Hospital Medical School, Imperial College of Science, London.
Anaesthesia. 1996 Jul;51(7):622-6. doi: 10.1111/j.1365-2044.1996.tb07842.x.
Sevoflurane is degraded by soda lime to a vinyl ether commonly referred to as compound A. We measured the concentration of compound A in the circle breathing system of 31 patients receiving sevoflurane anaesthesia. Inspiratory and expiratory gas samples were analysed using gas chromatography and flame ionisation detection. The end-tidal sevoflurane concentration and soda lime temperature were recorded. The peak compound A concentration ranged between 10 to 32 ppm in the inspiratory limb and 7 to 26 ppm in the expiratory limb. There was a positive correlation between the peak compound A concentration and the end-tidal sevoflurane concentration (r2 = 0.545, p < 0.0001) and the soda lime temperature (r2 = 0.301, p = 0.0014). We conclude that the end-tidal concentration of sevoflurane and the temperature of the soda lime are important variables in determining concentration of compound A in a circle system.
七氟烷被碱石灰降解为一种通常称为化合物A的乙烯基醚。我们测量了31例接受七氟烷麻醉患者的循环呼吸系统中化合物A的浓度。使用气相色谱法和火焰离子化检测对吸气和呼气气体样本进行分析。记录呼气末七氟烷浓度和碱石灰温度。吸气支路中化合物A的峰值浓度在10至32 ppm之间，呼气支路中在7至26 ppm之间。化合物A的峰值浓度与呼气末七氟烷浓度（r2 = 0.545，p < 0.0001）和碱石灰温度（r2 = 0.301，p = 0.0014）之间存在正相关。我们得出结论，呼气末七氟烷浓度和碱石灰温度是决定循环系统中化合物A浓度的重要变量。
