Stahl J M, Cutfield G R, Harrison G A
Department of Anaesthetics, St. Vincent's Hospital, Sydney, New South Wales, Australia.
Anaesth Intensive Care. 1992 May;20(2):177-86. doi: 10.1177/0310057X9202000211.
The effect on alveolar oxygen fraction (FAO2) of insufflating oxygen under a mask (or through an inflow nipple provided in the mask) during simulated mouth-to-mask ventilation was investigated using a lung model. A variety of commercially produced masks were evaluated. Two patterns of artificial ventilation were applied: 1. 500 ml tidal volume at 20 breaths per minute, and 2. 900 ml tidal volume at 12 breaths per minute. The ventilating gas mixture was oxygen 16% in nitrous oxide, and oxygen was insufflated at flow rates of 2, 4, 6, 8, 10, 12 or 14 litres per minute. The rate of rise of FAO2 and the equilibrium FAO2 attained were greatest at high oxygen inflow rates. The relationship between oxygen flow and FAO2 was not linear however, and an oxygen flow rate of 10 l/min was adequate to generate FAO2's around 50% with either ventilatory pattern. The equilibrium FAO2 achieved was greater with smaller tidal volumes and with larger mask deadspace. We also found that several breaths were required for equilibration of FAO2 during each trial, supporting recommendations that several breaths should be given on commencement of artificial ventilation during cardiopulmonary resuscitation.
使用肺模型研究了在模拟口对口面罩通气期间通过面罩（或通过面罩中提供的流入乳头）吹入氧气对肺泡氧分数（FAO2）的影响。评估了各种商业生产的面罩。应用了两种人工通气模式：1. 每分钟20次呼吸、潮气量500毫升；2. 每分钟12次呼吸、潮气量900毫升。通气混合气体为一氧化二氮中含16%氧气，氧气以每分钟2、4、6、8、10、12或14升的流速吹入。在高氧气流入速率下，FAO2的上升速率和达到的平衡FAO2最大。然而，氧气流量与FAO2之间的关系不是线性的，对于任何一种通气模式，10升/分钟的氧气流速足以产生约50%的FAO2。较小的潮气量和较大的面罩死腔可实现更高的平衡FAO2。我们还发现，每次试验中FAO2达到平衡需要几次呼吸，这支持了在心肺复苏期间开始人工通气时应给予几次呼吸的建议。
