DOES THE PLATELET-ACTIVATED CLOTTING TEST (HEMOSTATUS(R)) PREDICT BLOOD-LOSS AND PLATELET DYSFUNCTION ASSOCIATED WITH CARDIOPULMONARY BYPASS

Platelet dysfunction is a major cause of bleeding after cardiopulmonar y bypass (CPB). No timely, simple, point-of-care determinant of platel et function is available for clinical use. Adding platelet-activating factor to conventional activated clotting time methods (platelet-activ ated clotting test [PACT]) (HemoSTATUS(R); Medtronic, Inc., Parker, CO ) produces rapid results (<3 min) and may yield a measure of platelet responsiveness and whole blood procoagulant activity. Blood samples we re drawn for PACT, platelet count, prothrombin time, activated partial thromboplastin time, and thromboelastogram (TEG) from 200 patients un dergoing cardiac surgery. The PACT significantly decreased from the ba seline to postprotamine time interval (P < 0.001). The PACT correlated with 4-h mediastinal blood loss (r = -0.30, P = 0.014). The TEG maxim um amplitude also correlated with 4-h mediastinal blood loss (r = -0.3 2, P = 0.003). The PACT had a sensitivity and specificity comparable t o routine laboratory coagulation tests in predicting blood loss. The T EG maximum amplitude, however, was more predictive than both the PACT and routine coagulation tests in this respect. The PACT may be a usefu l indicator of platelet responsiveness or whole blood procoagulant act ivity, but we did not find it superior to other tests of coagulation f unction for predicting excessive blood loss after CPB.