Identification of patients at risk for excessive blood loss during coronary artery bypass surgery: thromboelastography versus coagulation screen.

In light of the potential morbidity associated with transfusion of blood products, a reliable preoperative screening test to identify cardiothoracic surgical patients who are at potential risk for increased intraoperative blood loss would be useful. Accordingly, we examined the efficacy of a variety of coagulation tests to predict intraoperative blood loss in 60 patients presenting for coronary artery bypass surgery (CABG). A complete coagulation screen, activated clotting time (ACT), and thromboelastograph (TEG) were performed before surgery. Intraoperative blood loss was determined by weighing sponges and measuring the quantity of blood in suction canisters. The duration of cardiopulmonary bypass was 100 +/- 4 min, and total surgery time was 5.0 +/- 0.1 h. Total crystalloid and colloid requirements were 5.5 +/- 0.2 and 1.4 +/- 0.1 L. Forty-eight percent of the patients required blood with an average requirement of 2.5 +/- 0.5 units. Total intraoperative blood loss averaged 1590 +/- 95 mL with a range from 640 to 3928 mL. Using multiple linear regression, all coagulation and TEG variables were used to model perioperative blood loss. Results showed that all components of the TEG failed to predict blood loss (r < 0.25, P > 0.78). However, three components of the routine coagulation assay, including bleeding time, prothrombin time, and platelet count could be modeled to predict perioperative blood loss (r = 0.75, P < 0.05). Although TEG has been shown to have potential in identifying postcardiopulmonary bypass coagulopathies, these results suggest that it does not appear to be useful in determining the coagulation status of CABG patients preoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)