Coagulation studies during experimental hemoglobinemia in humans.

Infusion of autologous hemolyzed blood in humans has served as a model for various experimental investigations for many years. Numerous studies have shown this model to be unattended by any adverse clinical reactions. In this study evidence of subclinical disseminated intravascular coagulation (DIC) was sought in normal humans infused with autologous hemolyzed blood. Hemoglobinemia was induced in 10 experiments by a single injection of frozen-thawed blood and in 4 experiments by such an injection of hemolysate followed by a 5-h maintenance infusion. Mean peak plasma hemoglobin following single dose injections was 540 mg/100 ml, while levels during continuous infusion averaged 240 mg/100 ml. The induction of hemoglobinemia was asymptomatic. Coagulation studies showed no significant alteration in prothrombin time, partial thromboplastin time, thrombin time, clottable fibrinogen, or WBC. Fibrin degradation products were not found. Platelet counts fell slightly in the 5-min postinfusion sample but returned to preinfusion levels within 30 min, suggesting a temporary sequestration of platelets rather than consumption. The induction of moderate brief experimental hemoglobinemia in normal subjects did not result in the development of demonstrable DIC.