Difference between plasma and red cell flow characteristics of pulmonary vascular bed

Abstract

In open-chested, anesthetized dogs the pulmonary artery and pulmonary vein were catheterized and simultaneous dye dilution curves were obtained for Cr⁵¹-tagged red cells and I¹³¹-tagged plasma. The curves were analyzed by electronic analogue computer techniques to obtain pulmonary transfer characteristics. Typical results are shown and a possible explanation of their significance is presented. Mean transit times for cells and plasma were calculated and the ratio cell/plasma transit time was found to be .91 ± .05 (P < .001), a value significantly lower than that usually reported for the ‘central circulation.’ The difference results from the more peripheral sampling sites used by other investigators.