Moll Jorge Ronaldo, Vieira Joaquim Edson, Gozzani Judymara Lauzi, Mathias Lígia Andrade Silva Telles
Hospital Geral de Bonsucesso do Ministério da Saúde, Rio de Janeiro, RJ, Brazil.
Departament of Surgery, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil.
Braz J Anesthesiol. 2014 May-Jun;64(3):164-8. doi: 10.1016/j.bjane.2013.06.011. Epub 2013 Oct 11.
Few investigations have addressed the safety of oxygen from concentrators for use in anesthesia in association with nitrous oxide. This study evaluated the percent of oxygen from a concentrator in association with nitrous oxide in a semi-closed rebreathing circuit.
Adult patients undergoing low risk surgery were randomly allocated into two groups, receiving a fresh gas flow of oxygen from concentrators (O293) or of oxygen from concentrators and nitrous oxide (O293N2O). The fraction of inspired oxygen and the percentage of oxygen from fresh gas flow were measured every 10 min. The ratio of FiO2/oxygen concentration delivered was compared at various time intervals and between the groups.
Thirty patients were studied in each group. There was no difference in oxygen from concentrators over time for both groups, but there was a significant improvement in the FiO2 (p<0.001) for O293 group while a significant decline (p<0.001) for O293N2O. The FiO2/oxygen ratio varied in both groups, reaching a plateau in the O293 group. Pulse oximetry did not fall below 98.5% in either group.
The FiO2 in the mixture of O293 and nitrous oxide fell during the observation period although oxygen saturation was higher than 98.5% throughout the study. Concentrators can be considered a stable source of oxygen for use during short anesthetic procedures, either pure or in association with nitrous oxide at 50:50 volume.
很少有研究探讨用于麻醉的制氧机所产氧气与一氧化二氮联合使用时的安全性。本研究评估了在半紧闭式再呼吸回路中，制氧机所产氧气与一氧化二氮联合使用时的氧含量百分比。
将接受低风险手术的成年患者随机分为两组，分别接受来自制氧机的新鲜氧气流（O293组）或来自制氧机的氧气与一氧化二氮的新鲜气体流（O293N2O组）。每10分钟测量一次吸入氧分数和新鲜气体流中的氧含量百分比。比较不同时间间隔以及两组之间的FiO2/输送氧浓度比值。
每组研究30例患者。两组制氧机所产氧气随时间均无差异，但O293组FiO2有显著改善（p<0.001），而O293N2O组有显著下降（p<0.001）。两组FiO2/氧比值均有变化，O293组达到平台期。两组脉搏血氧饱和度均未降至98.5%以下。
在观察期内，O293与一氧化二氮混合气体中的FiO2下降，尽管在整个研究过程中氧饱和度高于98.5%。制氧机可被视为短时间麻醉过程中稳定的氧气来源，无论是纯氧还是与体积比为50:50的一氧化二氮联合使用。
