Gledhill N, Froese A B, Buick F J, Bryan A C
J Appl Physiol Respir Environ Exerc Physiol. 1978 Oct;45(4):512-5. doi: 10.1152/jappl.1978.45.4.512.
Pulmonary gas exchange was studied in five normal subjects both at rest and during moderate steady-state exercise on a bicycle ergometer while breathing a) room air and b) a mixture of 20.9% O2-balance sulfur hexafluoride (SF6). The alveolar-arterial oxygen pressure differences (AaDO2) widened significantly from rest to exercise. Breathing the O2-SF6 mixture reduced the AaDo2 significantly from 10.9 to 4.2 Torr at rest and from 15.5 to 10.1 Torr during exercise (P less than or equal to 0.01). There were no concurrent changes in metabolism, cardiac output, or heart rate during the SF6 breathing. Possible changes in the anatomic shunt fraction, alveolar-end-capillary equilibration, or the distribution of blood flow cannot account for these observations. We conclude that the AaDO2 increase during exercise reflects an inhomogeneity of ventilation-perfusion ratios (VA/Q) most probably arising within regions of the lung (intraregional inhomogeneity) rather than between regions (interregional inhomogeneity).
对五名正常受试者进行了肺气体交换研究，在静息状态以及在自行车测力计上进行中等强度稳态运动期间，分别让他们呼吸：a）室内空气；b）含20.9%氧气 - 其余为六氟化硫（SF6）的混合气体。从静息到运动，肺泡 - 动脉氧分压差（AaDO2）显著增大。呼吸O2 - SF6混合气体时，静息时AaDo2从10.9 Torr显著降至4.2 Torr，运动时从15.5 Torr降至10.1 Torr（P≤0.01）。在呼吸SF6期间，代谢、心输出量或心率无同时发生的变化。解剖分流分数、肺泡 - 毛细血管末端平衡或血流分布的可能变化无法解释这些观察结果。我们得出结论，运动期间AaDO2的增加反映了通气 - 灌注比（VA/Q）的不均匀性，最有可能是在肺区域内产生（区域内不均匀性），而非区域间（区域间不均匀性）。
