The effect of variations in airflow pattern on gas exchange. A theoretical study.

It has been shown that gas exchange between the alveolar space and pulmonary capillary blood is affected by the pattern of airflow at the mouth in the non-homogeneous lung. The present theoretical study shows that even in the homogeneous lung, the pattern of airflow can affect gas exchange. When tidal volume, inspiratory and expiratory times remain constant, variations in the pattern of airflow result in significantly different values of steady state arterial PO2 and PCO2. This difference in steady state blood gases is exaggerated by low levels of minute ventilation and by long inspiratory times, but is unaffected by changes in the diffusion coefficient of the alveolar-capillary membrane.