基于血氧饱和度计算客舱应急补氧量的研究

Calculation of Emergency Oxygen Replenishment in Cabin Based on Blood Oxygen Saturation

目的现行的运输类飞机适航标准CCAR 25.1443(c)中对乘客遭遇座舱失压时最小气管氧分压的规定并不能反映乘客在缺氧状况下的实际生理状况,基于血氧饱和度水平提出了与CCAR 25.1443(c)等效的补氧设想。方法首先建立气管氧分压和肺泡氧分压的计算模型,并分析二者之间的关系;然后分析不同高度下人体血氧饱和度水平,并根据模型计算不同高度下的肺泡氧分压;最后根据同一高度下的肺泡氧分压与血氧饱和度的对应关系提出了与CCAR 25.1443(c)等效的最低血氧饱和度水平。结果对于长时间持续暴露在高空的客舱乘客,其动脉血氧饱和度应不低于92%;对于短时间暴露在高空的客舱旅客,其动脉血氧饱和度应不低于85%。结论将CCAR 25.1443(c)中关于乘客最小补氧流量的规定建议修改为基于最小血氧饱和度的规定,此参数可准确反映出乘客的脑组织供氧水平。

Objective The current regulation of minimum partial oxygen pressure in the trachea of passengers encountering cabin decompression in airworthiness standard of transport aircraft CCAR 25.1443(c)does not reflect the actual physiological status of passengers under hypoxia.The conception of oxygen supplement equivalent to CCAR 25.1443(c)based on the level of oxygen saturation was proposed.Methods Firstly,the calculation models of tracheal oxygen partial pressure and alveolar oxygen partial pressure were established and the relationship between them was analyzed.Then the levels of oxygen saturation in human blood at different heights were analyzed,and the alveolar oxygen partial pressure at different heights was calculated according to the model.Finally,according to the corresponding relationship between alveolar oxygen partial pressure and oxygen saturation at the same altitude,the lowest oxygen saturation level equivalent to CCAR 25.1443(c)was proposed.Results For passengers exposed to high altitude for a long time,the arterial oxygen saturation should not be less than 92%;For passengers exposed to high altitude for a short time,the arterial oxygen saturation should not be less than 85%.Conclusion It is proposed that the CCAR 25.1443(c)on the minimum supplemental oxygen flow rate for passengers can be modified to be based on the minimum oxygen saturation.The modified concept of oxygen supplement can more accurately reflect the oxygen supply level in the passengers’ brain tissue.