Reinfusion of aspirated pericardial blood during CPB. Part II. Laparotomy sponges are hazardous parts of the CPB circuit?

Usually, cotton laparotomy sponges are discarded when they become blood soaked. During bypass surgery, however, they are often wrung out into the pericardial sac and the contents of the sac are aspirated into the cardiopulmonary bypass (CPB) circuit. After cardiopulmonary bypass, many patients give evidence of mental confusion, excessive bleeding, and systemic inflammatory response syndrome (SIRS). We believe that a possible cause is reinfusion of blood that has been activated by contact with laparotomy sponges and contains fibrin microemboli and thrombin. Thrombin production, soluble fibrin (SF) development, and fibrinogen disappearance were measured, over time, in model systems composed of increasing amounts (0-10-20 microL) of tissue factor (TF) in 4 ml of anticoagulated blood distributed through the interstices of a 49-cm(2) laparotomy sponge. Clotting occurred in all of the sponges. Clotting was accelerated by the presence of TF. Without TF, clotting occurred in an average of 28 min (range 17-39). With 10 and 20 microl TF, clotting occurred in 20 (range 11-27) and 13 (range 10-16) min, respectively. Thrombin at a level of approximately 16 NIHU/ml whole blood was present in several donors for 10-20 min after clotting was complete. If 120 ml of blood was to be wrung from a full-sized laparotomy sponge at this point in time, it could contain as much as 2000 units of thrombin.