Unequal distribution of pulmonary diffusing capacity and the alveolar-arterial PO₂ differences: theory

¹ Department of Physiology, University of Buffalo School of Medicine, Buffalo, New York

The effects of unequal distribution of pulmonary diffusing capacity to the pulmonary blood flow on the alveolar-arterial O₂ pressure difference have been studied theoretically. It is demonstrated that, if the diffusing capacity is not distributed proportionally to the blood flow in a lung, the alveolar-arterial O₂ pressure difference will in most circumstances be greater than in a lung with the same total diffusing capacity and the same total blood flow, but with equal distribution of diffusing capacity to blood flow.