The occasional occurrence of spontaneous fibrinolysis following major surgical procedures resulting in altered blood coagulation and bleeding has been noted with increasing interest.
Numerous investigations recently reviewed by Astrup,3 Albrechtsen,1 Cooper,6 and Cohen and Warren5 have established that normal human blood contains an inactive proteolytic globulin termed plasminogen (profibrinolysin) (Fig 1). In the presence of certain activating substances in the blood, tissues, urine, or of bacterial origin, eg, streptokinase, staphylokinase, this globulin is converted to the active enzyme plasmin (fibrinolysin). This enzyme is capable of hydrolyzing the internal peptide bonds of the fibrin in the blood clot or other proteins containing structural sites suitable for activation by plasmin.12 Free plasmin in the blood is neutralized by various inhibitors (antiplasmin).17 Similarly, inhibitors of plasminogen activation are also known to exist.5
A significant observation by many surgeons has been the presence of excessive oozing in patients