Anderson B J, Dyson A, Henderson A M
Department of Anaesthesia, Middlemore Hospital, Auckland, New Zealand.
Anaesth Intensive Care. 1988 Nov;16(4):423-6. doi: 10.1177/0310057X8801600407.
Ten volunteers were given varying ratios of oxygen and nitrous oxide at 4, 6 and 8 litres per minute using a Hudson mask delivery system. Maximum and minimum inspired oxygen concentrations, maximum inspired nitrous oxide concentrations and end tidal carbon dioxide concentrations were measured using the Datex Cardiocap CCI-104 monitor. Although pharyngeal oxygen fraction varies with the Hudson mask because the inspiratory flow exceeds the entrainment of the mask by a variable amount during much of the cycle, at 8 litres/minute flow with a ratio of 3 to 5, oxygen to nitrous oxide, safe levels of oxygen were delivered (range of means 26-31%) with basal nitrous oxide levels (mean maximum inspired N2O, 34%). When nitrous oxide sedation is used clinically, nitrous oxide must be used with consideration of safe oxygen levels. This study did not detect unsafe pharyngeal oxygen levels in the ratios investigated, where the maximum delivered nitrous oxide concentration was 75%.
使用哈德森面罩输送系统，以每分钟4升、6升和8升的流量，给10名志愿者提供不同比例的氧气和一氧化二氮。使用Datex Cardiocap CCI - 104监测仪测量最大和最小吸入氧浓度、最大吸入一氧化二氮浓度以及呼气末二氧化碳浓度。尽管由于在大部分周期中吸气流量超过面罩的夹带量而变化不定，导致哈德森面罩的咽部氧分数有所不同，但在流量为每分钟8升、氧气与一氧化二氮比例为3比5时，可输送安全水平的氧气（平均范围为26% - 31%），同时一氧化二氮处于基础水平（平均最大吸入N2O为34%）。在临床使用一氧化二氮镇静时，必须考虑安全氧水平来使用一氧化二氮。本研究在所研究的比例中未检测到不安全的咽部氧水平，其中最大输送的一氧化二氮浓度为75%。
