Effect of Blood Transfusion and Hemorrhage on Cardiac Output and on the Venous Return Curve

The effect of blood transfusion or hemorrhage on the venous return curve has been studied in 10 dogs with normal circulatory reflexes and in 10 additional areflex dogs. At all right atrial pressures transfusion increased the venous return and hemorrhage decreased it. Following transfusion the venous return remained elevated only transiently, returning progressively toward the control value during the ensuing 10–20 minutes. Following hemorrhage, however, the venous return remained depressed for prolonged periods of time. The same effects were observed after infusion of Tyrode's solution as after transfusion of blood.