Blood conservation in coronary artery surgery

Most patients undergoing coronary artery bypass surgery receive homologous blood transfusions despite the availability of multiple pharmacologic and blood salvage conservation strategies.

The efficacy of defining strict transfusion criteria as the sole blood conservation strategy was adjudicated prospectively by comparing homologous blood product usage in 314 consecutive patients undergoing isolated primary coronary artery bypass surgery (group 2) with a retrospective group of 947 consecutive patients undergoing the same procedure but transfused without protocol (group 1).

The incidence of red cell transfusion and plasma transfusion decreased from 40.5% to 25.8% and 23.8% to 13.4% in groups 1 and 2, respectively (p < 0.001). The percentage of patients receiving no homologous blood products increased from 47.6% in group 1 to 68.5% in group 2 (p < 0.001). Decreasing body weight and preoperative hematocrit were found to be highly significant predictors of the need for red blood cell transfusion (p < 0.001). Significant postoperative determinants included intensive care unit and hospital length of stay and reoperation for bleeding (p < 0.001 each).

Because major determinant of homologous blood transfusion during coronary bypass surgery is the predictable and unavoidable dilution of a small red cell mass that occurs when instituting cardiopulmonary bypass, adherence to defined transfusion criteria alone is a simple, safe, and effective strategy for decreasing blood product utilization.