Background: Cardiac surgery performing with cardiopulmonary bypass (CPB) causes multiple alterations in the hemostatic system. In this study, we investigated the effect of acute normovolemic hemodilution on coagulation, fibrinolytic system and physiologic anticoagulants such as protein C and S among patients who underwent coronary artery bypass grafting (CABG).

Methods: Forty one patients who underwent CABG with (Group 1, n = 20) and without (Group 2, n = 21) acute normovolemic hemodilution were enrolled in this study. Activated clotting time (ACT), prothrombin time (PT), activated partial thromboplastin time (aPTT), D-dimer (fibrin degradation product), fibrinogen, protein C and S, and platelet count were measured. Blood samples were collected after induction of anesthesia, 20 minutes after the beginning of CPB, 30 minutes after administration of protamine, and 24 hours after the weaning from CPB. Transfused blood products and mediastinal bleeding were recorded.

Results:Within both groups, D-dimer elevated, and protein C values and platelet count decreased significantly at all samples compared with preoperative values. The changes of ACT, PT, aPTT, D-dimer, fibrinogen, protein C and S and platelet count were similar in both groups. There were no statistically significant differences between both groups with respect to the blood transfusion and mediastinal bleeding.

Conclusions:Acute normovolemic hemodilution in CABG surgery does not significantly decrease blood products requirements and the changes in hemostatic system are not effected by this technique.

Keywords : Coronary artery bypass grafting, hemodilution, blood transfusion, coagulation