Effects of stroma-free haemoglobin solution on the blood-clotting system in dogs.

The effect of transfusions of 500 ml of 5-6% stroma-free haemoglobin solutions on the blood-clotting system of dogs was studied. Slight lowering of the fibrinogen level and of the activity of clotting factors V, VII, VIII, IX and X was observed, together with some prolongation of the thrombin time. In vitro investigations indicate that prolongation of the thrombin time may depend on disturbed polymerization of fibrin monomers. After transfusion of stroma-free haemoglobin preparation, no signs of haemorrhagic diathesis were observed.