Effect of regional lung expansion and body position on pulmonary perfusion in dogs

E. MORRIS. Effect of regional lung expansion and body position on pulmonary perfusion in dogs. J. Appl. Physiol. 3 I(1) : 97-101. 1971.-We measured lung expansion and blood flow to multiple samples of lung obtained from dogs that were studied in the vertical head-up, horizontal supine, and horizontal prone posi-tions. In the vertical head-up dogs we found that the upper lung was 2-3 times more expanded than the lower lung and that blood flow was greatest in the midlung region. In horizontal slices of lung from those dogs where factors controlling flow through the collapsible alveolar vessels were constant, there was a rough cor-relation between blood flow and expansion (P = <0.05 in 6 of 12 slices examined). In the horizontal animals we compared blood flow at the same gravitational plane from apex to base in the lung (i.e., head to foot). In the prone position we found a positive correlation (P = <0.05) between blood flow and re-gional expansion in one animal. In the supine position the ex