Intravascular Haemolysis with Experimentally Produced Vascular Thrombi

SUMMARY Studies are presented on the haemoglobinaemia observed during intravascular coagulation in rabbits due to thrombin infusion or endotoxin injection. The haemoglobinaemia was unrelated to the type or amount of thrombin, but was closely correlated to the degree and extent of fibrin thrombi in the renal glomeruli and in the small vessels of other organs, an effect potentiated by thorotrast. The haemoglobinaemia was not dependent on the presence of the spleen or the kidneys, or on circulating granulocytes, but could be prevented by heparin. The haemoglobinaemia was associated with the appearance of fragmented red cells in the circulation. It is suggested that the haemoglobinaemia is due to intravascular destruction of red cells at the site of fibrin thrombi, and that changes in the red cell may also enhance thrombosis.