2％七氟醚两种低流量洗人半紧闭麻醉环路时的浓度变化

The concentration changes during two low initial fresh gas flow and 2 % sevoflurane wash in semiclosed-circuit anesthesia

目的观察2％七氟醚两种低流量洗入半紧闭环路的浓度变化。方法选择40例ASA分级Ⅰ～Ⅱ级择期行外科手术的患者，随机分为A、B两组，两组洗入新鲜气体流量分别为2．0IMmin或1．0L／min，七氟醚蒸发罐麻醉药设定浓度（FD）为2％。记录肺泡内麻醉药浓度（FA）、吸入麻醉药浓度（F1）和FA／F1。结果七氟醚低流量洗人120min后A组FA及F1分别为（1．47±0．12）％和（1．69±0．09）％，B组分别为（1．23±0．13）％和（1．46±0．11）％，两组内的FA与F1比较差异有统计学意义（P〈0．01）；FA／FD和F1／FD在A组分别为0．73±0．07和0．85±0．08，B组为0．62±0．06和0．73±0．07，两组间比较差异有统计学意义（P〈0．01）。A、B两组中的FA／F1分别为0．87±0．08和0．85±0．09，两组比较差异无统计学意义（P〉0．05）。结论2％七氟醚低流量洗入麻醉环路120min后对两组间的FA和F1有不同影响，但对两组间的FA／F1影响相似。

Objective To investigate the concentration changes of sevoflurane during semiclosedcircuit anesthesia with two low initial fresh gas flow. Methods Forty ASAⅠ-Ⅱ patients undergoing operation were randomly allocated to one of two equal groups （ n = 20）, The vaporize setting of both group were fixed at 2% sevoflurane,group A and group B receive either 2.0 or 1.0 L/rain fresh gas flow. The inspired （F1） ,end-tidal （FA ）, and ratio FA/F1 sevoflurane concentrations were estimated. Results After 120 minutes of sevoflurane anesthesia the inspired and end-tidal sevoflurane concentration were （ 1.47 ± 0.12） % versus （1.69 ±0.09）% （P〈0.01） in the group A and （1.23 ±0.13）% versus（1.46 ±0.11）% （P〈 0.01 ） in the group B. The ratio end-tidal and inspired concentrations/vaporizer setting was 0.73 ± 0.07 and 0.85 ± 0.08 in the group A versus 0.62 ± 0.06 and 0.73 ± 0.07 in the group B. For the ratio inspired and end-tidaL/vaporizer setting there were significant difference between the groups （ P 〈 0.01 ）. The estimated ratio end-tidal/inspired was 0.87 ± 0.08 in the group A versus 0.85 ± 0.09 in the group B （ P 〉 0. 05 ）. Conclusion After 120 minutes of sevotlurane anesthesia at a vaporizer setting of 2% there is a significant difference between tow groups for inspired and end-tidal concentrations, but not for the ratio FA/F1.