West J B, Hackett P H, Maret K H, Milledge J S, Peters R M, Pizzo C J, Winslow R M
J Appl Physiol Respir Environ Exerc Physiol. 1983 Sep;55(3):678-87. doi: 10.1152/jappl.1983.55.3.678.
Pulmonary gas exchange was studied on members of the American Medical Research Expedition to Everest at altitudes of 8,050 m (barometric pressure 284 Torr), 8,400 m (267 Torr) and 8,848 m (summit of Mt. Everest, 253 Torr). Thirty-four valid alveolar gas samples were taken using a special automatic sampler including 4 samples on the summit. Venous blood was collected from two subjects at an altitude of 8,050 m on the morning after their successful summit climb. Alveolar CO2 partial pressure (PCO2) fell approximately linearly with decreasing barometric pressure to a value of 7.5 Torr on the summit. For a respiratory exchange ratio of 0.85, this gave an alveolar O2 partial pressure (PO2) of 35 Torr. In two subjects who reached the summit, the mean base excess at 8,050 m was -7.2 meq/l, and assuming the same value on the previous day, the arterial pH on the summit was over 7.7. Arterial PO2 was calculated from changes along the pulmonary capillary to be 28 Torr. In spite of the severe arterial hypoxemia, high pH, and extremely low PCO2, subjects on the summit were able to perform simple tasks. The results allow us to construct for the first time an integrated picture of human gas exchange at the highest point on earth.
美国医学研究珠峰探险队的成员在海拔8050米（气压284托）、8400米（267托）和8848米（珠峰顶峰，253托）的高度对肺气体交换进行了研究。使用一种特殊的自动采样器采集了34份有效的肺泡气体样本，其中包括在顶峰采集的4份样本。在两名受试者成功登顶后的早晨，于海拔8050米处采集了静脉血。肺泡二氧化碳分压（PCO2）随着气压降低大致呈线性下降，在顶峰时降至7.5托。对于呼吸交换率为0.85的情况，这使得肺泡氧分压（PO2）为35托。在两名登顶的受试者中，8050米处的平均碱剩余为-7.2毫当量/升，假设前一天的值相同，那么在顶峰时动脉pH值超过7.7。根据肺毛细血管沿线的变化计算出动脉PO2为28托。尽管存在严重的动脉低氧血症、高pH值和极低的PCO2，但顶峰的受试者仍能够完成简单任务。这些结果使我们首次构建出地球上最高点人类气体交换的综合图景。
