EFFECTS OF MASSIVE TRANSFUSION AND HEMORRHAGE ON BLOOD PRESSURE AND FLUID SHIFTS

Abstract

Blood was removed from one group of dogs and injected respectively into a 2d group without the use of an anticoagulant, but using a special apparatus so that repeated increments of blood could be so transfused without coagulation. It was found that the blood pressure of the recipient animals rose only 17 mm. Hg above the control value, despite transfusions equal to 1.62 times as much blood as already in the dog''s body. The means by which the circulatory system prevented increased blood pressure appeared to be very rapid loss of fluid into the tissues, for at the end of these massive transfusions, requiring approx. 30 min. to perform, 63% of the transfused blood vol. had already been lost into the tissues. This loss was almost entirely plasma rather than cell loss, and the plasma carried with it almost normal concns. of protein into the tissues. The level at which the blood pressure tended to remain constant, regardless of progressive transfusion, was detd. to a great extent by tone of the sympathetics. Increased sympathetic tone due to pressoreceptor denervation resulted in a blood pressure plateau 54 mm. Hg above normal, and anesthetized sympathetics resulted in a plateau 70 mm. Hg below normal. The readjustments of blood pressure following hemorrhage occurred very much more slowly than did readjustments following transfusion.