Influence of hypoxia on the longitudinal distribution of pulmonary vascular resistance

Abstract

The influence of hypoxia on the longitudinal distribution of vascular resistance and intravascular pressure in isolated cat lungs using the low-viscosity bolus technique was examined. Hypoxia increased total vascular resistance, decreased total lung blood volume and moved the maximum local resistance downstream away from the main pulmonary artery. The circumference of the main pulmonary artery was increased, and the extravascular lung water (double indicator dilution technique) was decreased by hypoxia. The distension of the large pulmonary arteries and a decrease in the amount of lung tissue perfused apparently contributed to the change in resistance distribution brought about by hypoxia.