Blood volume and intravascular hematocrit in different vascular beds

¹ Department of Physiology, Medical College of Georgia, Augusta, Georgia

The relative volumes of cells and plasma in the isolated paw, kidney, ileum, and gracilis muscle were determined in 30 dogs by suddenly stopping the flow and washing out the vascular content with saline. Similar experiments were also performed in five dogs on the combined vascular beds draining through the superior and inferior venae cavae. Plasma volume was calculated by dividing the protein content of 1 ml plasma into the total protein recovered; red cell volume was calculated as average concentration of cells in the fluid recovered times its volume. Average blood flows in milliliters per minute per 100 g distended organ weight were 164.5 for the kidney, 26.3 for the ileum, 9.4 for the paw, and 6.4 for the muscle. Average vascular volumes in ml/100 g distended organ weight were 25.9 for the kidney, 8.9 for the ileum, 5.4 for the paw, 4.5 for the muscle, 2.4 for the inferior vena cava bed, and 1.7 for the superior vena cava bed. Average red cell concentrations (as % of the concentrations in the effluent vein during flow) were 69.0 for the kidney, 92.0 for the ileum, 87.0 for the paw, 81.8 for the muscle, 87.0 for the inferior vena cava bed, and 89.0 for the superior vena cava bed.