Alterations in Blood Coagulation Mechanism After Intra-Aortic Injection of Thrombin

Abstract

It was shown in 1955 that the injection of incompatible (human) blood into dogs resulted in alterations in the blood coagulation constituents and mechanism.¹ These changes included production of a thrombocytopenia, a decrease in number of white blood cells, a prolongation of prothrombin time, prolongation of the clotting time, a decrease in fibrinogen, and the appearance of a circulating heparinoid anticoagulant. Little or no fibrinolysin was evident. It was also demonstrated^2,3 that the injection of incompatible blood caused an episode of intravascular coagulation in the small vessels and capillaries. It was postulated^1,16 that the changes in the blood constituents and clotting mechanism were due to the using up of clotting elements by an episode of intravascular clotting and that the appearance of a heparinoid anticoagulant was a mechanism of defense by the body against the clotting episode. Because of the protean components of blood, the current interest