Original Article

Thrombelastograph Analysis After Heparin Neutralization with Protamine and Heparinase During Cardiopulmonary Bypass

University of Nebraska Medical Center, Division of Perfusion Sciences, Omaha, Nebraska

^* Address correspondence to: Curtis Forst, MA, Division of Perfusion, University of Nebraska Medical Center, 600 S. 42nd St., Omaha, NE 68198-5125

Abstract

Hemostatic disorders generated during cardiopulmonary bypass (CPB) result in postsurgical hemorrhage, a major cause of morbidity in cardiac patients. Thrombelastography (TEG) monitors elastokinetic whole blood coagulation but is sensitive to low quantities of circulating heparin, obviating its use during CPB. Heparinase is an enzyme that degrades heparin without affecting coagulation proteins that may aid in identifying coagulopathies during CPB.

In the present study two methods of neutralizing heparin were used to generate TEG profiles during CPB. These profiles were generated by adding 0.03 ml protamine (0.0134 mg) or heparinase (6 U) 0.33 ml samples of heparinized blood. Samples were drawn pre-CPB, 10 and 30 minutes after initiation of CPB, 5 minutes after administration of protamine and 10 minutes after administration of platelet-rich-plasma, from 11 patients undergoing cardiac surgery. The results indicate a significantly higher baseline reaction time between pre-CPB in both groups when compared to all other time points (p < 0.007). During CPB, both protamine and heparinase reversed the anticoagulant effect of heparin, permitting the generation of useful TEG data. We therefore conclude that intraoperative TEG profiles can be produced during CPB for the purpose of identifying hemostatic conditions prior to termination of extracorporeal circulation.