Transfusion practices among patients who did and did not predonate autologous blood before elective cardiac surgery

Background: Preoperative autologous blood donation is commonly used to redu ce exposure to allogeneic transfusions among patients undergoing elective c ardiac surgery. However, this technique is associated with an overall incre ase in transfusions (allogeneic or autologous). The authors assessed the im pact of transfusion decision-making on the effectiveness of preoperative au tologous donation in reducing the frequency of allogeneic transfusions, and its impact on the increased transfusion rate associated with preoperative autologous donation in cardiac surgery. Methods: This retrospective analysis compared transfusion practices among 1 76 patients who predonated autologous blood before elective cardiac surgery and 176 matched cardiac surgery patients who did not predonate blood. The impact of decision-making on transfusion exposure was determined using mult ivariate analyses to account for major perioperative interventions and comp lications. Odds ratios (ORs) and 95% confidence intervals (Cls) were calcul ated for exposure to allogeneic blood transfusion or any transfusion, befor e and after exclusion of transfusions not conforming with selected transfus ion criteria. Results: Exposure to allogeneic transfusion was more likely among patients who did not predonate blood than among those who did predonate blood (OR 14 .0, 95% CI 5.8-33.8). This finding was still true after exclusion of transf usions not meeting the transfusion criteria (OR 19.3, 95% Cl 6.7-55.7). The autologous blood donors were more likely than the nondonors to receive any transfusion (OR 10.8, 95% CI 5.7-20.3). However, this association was subs tantially attenuated after exclusion of transfusions not meeting the transf usion criteria (OR 1.9, 95% CI 1.1-3.2). Interpretation: Patients who predonated blood before elective cardiac surge ry were at lower risk of receiving allogeneic transfusions than the nondono rs. This was not because of a deliberate withholding of allogeneic transfus ions from autologous donors. However, more;liberal transfusion criteria for autologous blood were largely responsible for the increased transfusion ra te among the autologous donors.