Relation between alveolar surface tension and pulmonary vascular resistance

¹ Laboratory of Thoracic Physiology, Department of Surgery; and Department of Physiology, Washington University School of Medicine, St. Louis, Missouri

In order to examine the hypothesis that surface forces at the alveolar air-liquid interface may play a role in determining the course of pulmonary vascular resistance on negative-pressure inflation, resistance was studied as a function of lung volume for both air and dextran-filled dog lungs in excised preparations perfused with fresh dog blood under carefully controlled conditions. Results show that abolishing the interface by liquid filling does not alter the course of resistance significantly. It is thus concluded that the presence of the interface can have only a minor effect on the course of resistance and that purely volume-dependent factors are primarily responsible.