Blood transfusion requirements in coronary artery surgery with and without the activated clotting time (ACT) technique.

Control of anticoagulation during cardiopulmonary bypass (CPB) with the automated activated whole blood clotting time (ACT) and reversal of heparin after CPB using a computerized ACT dose-response curve method resulted in significant reductions of blood transfusion requirements, surgical time, and protamine doses in 150 patients undergoing coronary artery bypass grafting procedures (ACT group) as compared to 200 patients for whom a standard fixed dose protocol for heparin and protamine was used (control patients). Mean transfusion requirements were 1,938 +/- 60 SEM ml whole blood and 853 +/- 48.3 SEM ml red blood cells for control patients and 1,397 +/- 59 SEM ml whole blood (P less than 0.001) and 695 +/- 34 SEM ml red blood cells (P less than 0.01) in the ACT group. ACT group patients also required less protamine with 26.2 +/- 0.60 SEM ml Protamine 1,000 (Roche) as compared to 33.9 +/- 0.49 SEM ml for control patients (P less than 0.001) but more heparin with 31,440 +/- 783 SEM I.U. versus 26,760 +/- 263 SEM I.U. (P less than 0.001). Surgical time decreased from 321 +/- 5.5 SEM min for control patients to 289 +/- 5.4 SEM min for ACT group patients (P less than 0.001).