COAGULATION TESTS PREDICT BLEEDING AFTER CARDIOPULMONARY BYPASS

Objective: To determine the accuracy of coagulation profile laboratory tests, thromboelastography, and Sonoclot (SCT) values for predicting microvascular bleeding after cardiopulmonary bypass (CPB). Design: A p rospective, blinded trial. Setting: A large academic medical center. P articipants: Eighty-two adult patients undergoing elective cardiac sur gery. Interventions: Ten minutes after CPB, thromboelastography, SCT, and coagulation profile tests (bleeding time, prothrombin time, activa ted partial thromboplastin time, fibrinogen, fibrin split products, pl atelet count, mean platelet volume, and platelet hematocrit) were dete rmined from a whole blood sample taken from an existing arterial cathe ter. Patients were subjectively defined as ''bleeders'' or ''non-bleed ers'' by blinded clinical observers. Preoperative baseline tests were also obtained. Measurements and Main Results: Thirty of the 82 patient s (36.6%) were characterized as bleeders. Coagulation profile tests ha d the best correlation with intraoperative and postoperative blood los s, The specificity, sensitivity, and negative and positive predictive values were determined by receiver operating characteristic analysis, and the test values that differentiated normal from abnormal (bleeding ) patients were determined. The coagulation profile laboratory tests h ad the greatest maximal sensitivity and specificity for predicting ble eding. These predictive values were outside the normal range for these laboratory tests. The thromboelastography values that produced maxima l sensitivity and specificity were in the normal range for that test. Conclusion: Contrary to previous studies, coagulation profile tests ha d the greatest sensitivity and specificity to differentiate patients w ith excessive bleeding (abnormal) from those without excessive bleedin g (normal) after CPB. Therefore, these tests should be used to guide t ransfusion therapy in patients who have excessive bleeding after CPB. Copyright (C) 1997 by W.B. Saunders Company.