Influence of unilateral hypoxia on blood flow through the lungs in man in lateral position

Abstract

The relative blood flow through the separated lungs was determined with six subjects in lateral position. The amount of CO₂ eliminated from each lung and the end-tidal air composition gave the necessary data to determine the relative flow through each lung, at assumed total blood flows through both lungs of 3, 6 and 12 liters. The lower lung was allowed to breath 10% oxygen in nitrogen and the upper lung air. The values obtained at all the above mentioned total blood flows were about the same, and also did not show any difference from the values obtained when both lungs were breathing 30% oxygen in nitrogen. In the last case the relative blood flow is assumed to be the same as the relative oxygen uptake for each lung. Hypoxia on the lower lung thus does not cause any shift to the air-breathing lung. This is in contrast to earlier experiments, performed by the authors, with the subject in supine position. Using the same measuring technique, it was then found that hypoxia on one lung caused a large shift of blood to the air-breathing lung. Submitted on February 1, 1960