Pulmonary Vascular Volume, Resistance, and Compliance in Man

Abstract

Pulmonary blood volume was measured in 19 patients, with use of a dye-dilution method and simultaneous bilateral cardiac catheterization. Pulmonary mean transit time was measured by subtracting left atrial-to-peripheral artery mean transit time from pulmonary artery-to-peripheral artery mean transit time. Average pulmonary blood volume was 365 ml. per M. 2 (range 126 to 598 ml. per M. 2 ). This value is significantly smaller than previous estimates by less direct methods. The ratio of pulmonary blood volume to mean intravascular pressure was used as an indication of pulmonary vascular compliance. Patients with high pulmonary vascular resistance had relatively low pulmonary vascular compliance. A significant correlation between pulmonary blood volume and stroke volume was found, lending support to the hypothesis that the volume and elasticity of the pulmonary vascular bed contribute to the regulation of cardiac output.