Automated protamine dose assay in heparin reversal management after cardiopulmonary by pass.

BACKGROUND: To evaluate the impact of automated Protamine Dose Assay (PDA) performed with Hemochron 8000 (International Technodyne Company, Edison, NJ) on the management of heparin reversal after cardiopulmonary bypass (CPB). PDA was compared with empirical protamine to heparin ratio with regard to calculation of the protamine dose, and the sensitivity of PDA and ACT to residual circulating heparin after protamine administration was investigated too. DESIGN: prospective and randomized study. SETTING: cardiac surgical center of a General Hospital. PARTICIPANTS: 50 patients undergoing elective cardiac surgery with CPB. INTERVENTIONS: after CPB patients randomly received protamine according to our standard empirical ratio of 1 mg. protamine/100 U. heparin (group S, 24 patients), or to PDA result (group T, 26 patients) based on protamine titration method of determining circulating heparin. After protamine administration ACT and PDA were performed to assess heparin reversal and detect residual circulating heparin. Based on the PDA result, additional protamine was administered in both groups when required. MEASUREMENTS: in both groups basal and post-heparin ACT values, protamine doses, ACT and PDA after protamine administration were measured. RESULTS: The protamine dose was significantly lower (30%) in patients treated according to PDA. In 20% of patients showing normal ACT PDA revealed still circulating heparin, and additional protamine was required. In all other cases ACT and PDA both confirmed heparin reversal. CONCLUSIONS: PDA allowed us to administer a significantly lower amount of protamine. This can reduce incidence of adverse effects of over- and under-infusion of protamine. PDA also proved to be more sensitive than ACT in detecting residual circulating heparin after protamine administration.