Einarsson S, Stenqvist O, Bengtsson A, Houltz E, Bengtson J P
Department of Anaesthesia and Intensive Care, Sahlgren Hospital, University of Göteborg, Sweden.
Br J Anaesth. 1993 Aug;71(2):189-93. doi: 10.1093/bja/71.2.189.
We studied the elimination rate of nitrous oxide in 36 patients undergoing orthopaedic surgery. They were allocated randomly to one of six groups which differed in time of nitrous oxide exposure and mode of ventilation. In order to simulate recovery conditions, nitrous oxide administration was discontinued after 30, 60 or 120 min of exposure. Either normoventilation or hypoventilation was used. The mean excretion rate was 1 litre min-1 at 1 min, declining to 100 ml min-1 at 30 min, with relatively small effects of different modes of ventilation and times of exposure. In spite of an FIO2 of 0.30, there were significant decreases in SpO2 during both normo- and hypoventilation. The smallest end-tidal oxygen concentrations were reached at 10-15 min in the groups with hypoventilation, after 1 or 2 h of nitrous oxide exposure.
我们研究了36例接受骨科手术患者的氧化亚氮消除率。他们被随机分配到六组中的一组，这六组在氧化亚氮暴露时间和通气模式上有所不同。为了模拟恢复情况，在暴露30、60或120分钟后停止氧化亚氮给药。采用常通气或低通气。平均排泄率在1分钟时为1升/分钟，在30分钟时降至100毫升/分钟，不同通气模式和暴露时间的影响相对较小。尽管吸入氧分数为0.30，但在常通气和低通气期间，脉搏血氧饱和度均显著下降。低通气组在氧化亚氮暴露1或2小时后，在10 - 15分钟时达到最低呼气末氧浓度。
