【摘要】 目的研究半紧闭装置高流量时氧化亚氮对异氟醚吸入和呼出浓度的影响。方法60例ASAⅠ~Ⅱ级静吸复合麻醉腹部手术患者随机分为氧化亚氮组(Ⅰ组)和纯氧组(Ⅱ组),各30例,分别在新鲜气流量O22 L/min+N2O 4 L/min或O26 L/min下接受0.8%异氟醚。用Datex-Ohmeda S/5气体监测仪监测新鲜气流量中异氟醚浓度(Fd),连续监测麻醉气体吸入浓度(Fi)、呼气末浓度(Fa)、呼气末二氧化碳分压(PETCO2)、吸入氧浓度(FiO2),观察10 min。结果Ⅰ组异氟醚Fd显著低于Ⅱ组(P<0.01);2组异氟醚Fi上升迅速,很快和Fd接近,相同时间点Ⅰ组显著低于Ⅱ组(P<0.05),Fa2组无明显差异;Ⅰ组异氟醚的Fa/Fi上升速率明显高于Ⅱ组(P<0.05)。结论半紧闭装置高流量时加吸氧化亚氮虽可降低异氟醚挥发罐的输出浓度和吸入浓度,但呼气末浓度并未降低,存在第二气体效应。更多还原

【Abstract】 Objective To investigate the effect of nitrous oxide(N2O) on the inspired and expired concentrations of isoflurane in the high fresh gas flow(FGF) anesthesia via semi-closed system.Methods Sixty patients were randomly divided into two groups(n=30 each): in group Ⅰ,the nitrous oxide group,the FGF given contained O2 2 L/min + N2O 4 L/min,while that in group Ⅱ,the pure oxygen group,the FGF was O2 6 L/min.The patients were put on 0.8% isoflurane anesthesia.Using Datex-Ohmeda S/5 gas machine,the concentration of isoflurane in FGF(Fd),the inspired and alveolar concentrations of isoflurane and N2O(Fi and Fa),as well as PETCO2 and FiO2,were observed for 10 min.Results The Fd of isoflurane in group Ⅰ was lower than that in group Ⅱ(P<0.01).The Fi of isoflurane rose rapidly in both groups,approaching the value of Fd,and the Fi of isoflurane in group Ⅰ was lower than that in group Ⅱ at the corresponding points(P<0.05).There were no significant differences in Fa between the two groups.The Fa/ Fi of isoflurane rose faster in group Ⅰ than in group Ⅱ(P<0.05). Conclusion N2O decreases the outflow and inspired concentrations of isoflurane vapor,but doesn′t decrease its alveolar concentration.A second gas effect is present in high fresh gas flow anesthesia via semi-closed system.更多还原