氧化亚氮对异氟醚吸入浓度的影响  

The effect of supplemental nitrous oxide on inspired and expired concentration of isoflurane

作　　者：汪正平[1] 吴俭[1] 李士通[1] 庄心良[1] 

机构地区：[1]上海交通大学附属第一人民医院麻醉科,200080

出　　处：《临床麻醉学杂志》2005年第1期23-25,共3页Journal of Clinical Anesthesiology

摘　　要：目的　了解新鲜气流中加入氧化亚氮对异氟醚吸入浓度的影响。方法　80例ASA Ⅰ～Ⅱ级全身麻醉的手术患者,随机分为纯氧组(Ⅰ组)和氧气 氧化亚氮组(Ⅱ组),各40例。充分去 氮,静脉诱导气管插管,控制呼吸,维持PETCO230～34mmHg。调节新鲜气体流量:Ⅰ组氧气 1L/min;Ⅱ组氧气和氧化亚氮各0.5L/min。异氟醚蒸发器开至1.6%刻度,于吸入麻醉开始、麻醉 后5、10、20、30、40和60min测定新鲜气、吸入和呼出异氟醚浓度、MAP、HR、SpO2、PETCO2。结果 (1)两组异氟醚吸入浓度逐渐升高,麻醉后5、10和20minⅠ组高于Ⅱ组(P<0.05,P<0.01),至30 min后浓度上升缓慢,两组间无显著性差异;(2)呼出和呼出/吸入浓度比两组间无显著性差异;(3)新 鲜气流中异氟醚浓度Ⅰ组显著高于Ⅱ组。结论　新鲜气流中加用氧化亚氮早期可减慢吸入异氟醚 浓度的上升速度,其原因主要是氧化亚氮使蒸发器输出浓度下降所致。Objective To investigate the influrence of nitrous oxide (N 2O) inhalation on the inspired and expired concentration of isoflurane.Methods Eighty adult patients scheduled for selective surgery under general anesthesia were randomly assigned to one of the two groups (n=40 for each ). Patients in group I inhaled isoflurane in O 2 for anesthesia maintenance, and group Ⅱ,isoflurane with 50% N 2O and 50% O 2. Anesthesia was induced with midazolam 2mg, fentanyl 0.2mg, propofol 1.5mg/kg and succinylcholine 1.5mg/kg intravenously. After endotracheal intubation, all patients were ventilated with P ETCO 2 between 30-34mmHg. In group I the fresh gas flow was 1L/min of O 2, and in group Ⅱ the fresh gas flow was 0.5L/min of O 2 with 0.5L/min of N 2O. The isoflurane vaporizer was kept at 1.6%. The concentrations of isoflurane in fresh gas flow, inspired and end-expired gas were measured at 0, 5, 10, 20, 30, 40 and 60min of isoflurane inhalation. The MAP, HR, SpO 2 and P ETCO 2 were also recorded at the same time points.Results (1) The inspired concentrations of isoflurane in group I were higher than those in group Ⅱ (P<0.05,P<<0.01) at same time at the first 20 minutes of inhalation. However, there was no statistical difference between them after 20 minutes of inhalation. (2) The end-expired concentration and ET/FI ratio of concentration in two group had no significant differences in the same period of inhalation. (3) The concentrations of isoflurane in fresh gas flow in group I were higher than those in group Ⅱ(P<0.01) all the time.Conclusion The establishment of isoflurane concentration was slowed in the early period of inhaled anesthesia when N 2O was added in the fresh gas of oxygen because N 2O decreased the outflow concentration of isoflurane vaporizer.

关 键 词：氧化亚氮 异氟醚 吸入浓度 全身麻醉 

分 类 号：R614[医药卫生—麻醉学]