Thromboelastography and Activated Clotting Time as Guides to Prediction of Postoperative Bleeding in Cardiac Patients with Administration of Aprotinin

Bae, Jin Ho; Ham, Byung Moon

Abstract

BACKGROUND: Activated clotting time (ACT) and thromboelastography (TEG) are generally accepted as adequate measures of the coagulation system for monitoring of the cardiac system. Aprotinin is alleged to affect ACT and TEG. We performed this study to see if the determination of ACT and TEG can provide a basis for the assessment of coagulation and the prediction of postoperative hemorrhage in cardiac surgical patients treated with aprotinin.
METHODS
Twenty patients undergoing cardiac operation were studied. The values (control) of ACT and TEG were obtained just after induction of anesthesia. Each patient was fully heparinized and received aprotinin, 2,000,000 KIU added to the prime solution. At the end of the procedure, protamine, 3 mg/kg was given for the neutralization of heparin. Measurement of ACT and TEG were made 20 minutes after the administration of protamine, at the end of surgery, and 1 hour after transfer to ICU. The values were compared with the amount of hemorrage collected by chest tubes 1 hour, 2 hours and 8 hours after transferred to ICU.
RESULTS
The values of ACT at 20 minutes after protamine administration and at the end of surgery significantly (P < 0.05) increased compared with the values of control, but the values in ICU did not show significant change. All values of TEG significantly (P < 0.05) changed compared with the values of control. No single variable of ACT and TEG showed correlation with the amount of hemorrhage through chest tubing postoperatively.
CONCLUSIONS
The results indicate that neither ACT nor TEG predict the amount of postperative hemorrhage in aprotinin-treated patients having cardiac surgery. Therefore the TEG results should be interpreted cautiously because of the high rate of unreliable results.