Peyton P J, Stuart-Andrews C, Deo K, Strahan F, Robinson G J B, Thompson B R, Pierce R
Joint Director of Research, Department of Anaesthesia, Austin Hospital, Heidelberg, 3084, Melbourne, Australia.
Anaesthesia. 2006 Apr;61(4):322-9. doi: 10.1111/j.1365-2044.2006.04579.x.
Theoretical modelling predicts that the concentrating effect of nitrous oxide (N2O) uptake on alveolar oxygenation is a persisting phenomenon at typical levels of ventilation - perfusion (V/Q) inhomogeneity under anaesthesia. We sought clinical confirmation of this in 20 anaesthetised patients. Arterial oxygen pressure (P(aO2)) was measured after a minimum of 30 min of relaxant general anaesthesia with an inspired oxygen (F(I O2)) of 30%. Patients were randomly allocated to two groups. The intervention group had N2O introduced following baseline blood gas measurements, and the control group continued breathing an identical F(I O2) in nitrogen (N2). The primary outcome variable was change in P(aO2). Mean (SD) in P(aO2) was increased by 1.80 (1.80) kPa after receiving a mean of 47.5 min of N2O compared with baseline conditions breathing O2/N2 (p = 0.01). This change was significantly greater (p = 0.03) than that in the control group: + 0.09 (1.37) kPa, p = 0.83 and confirms the presence of significant persisting concentrating and second gas effects.
理论模型预测，在麻醉状态下典型的通气-灌注（V/Q）不均一水平时，氧化亚氮（N2O）摄取对肺泡氧合的浓缩效应是一种持续存在的现象。我们在20例麻醉患者中寻求对此的临床证实。在吸入氧浓度（F（I O2））为30%的肌肉松弛全身麻醉至少30分钟后，测量动脉血氧分压（P（aO2））。患者被随机分为两组。干预组在基线血气测量后引入N2O，对照组继续吸入氮气（N2）中相同的F（I O2）。主要结局变量是P（aO2）的变化。与吸入O2/N2的基线情况相比，在平均吸入47.5分钟N2O后，P（aO2）的平均值（标准差）增加了1.80（1.80）kPa（p = 0.01）。这一变化显著大于对照组（p = 0.03）：+ 0.09（1.37）kPa，p = 0.83，证实存在显著的持续浓缩效应和第二气体效应。
