Purpose: Determinants of allogeneic blood use in cardiac surgery include preoperative factors such as female sex, age, body weight, hematocrit and red cell volume. We verified if these variables also predicted the need for allogeneic transfusions when autologous blood is predonated.
Methods: Demographic and intraoperative variables, hemoglobin concentrations and transfusion requirements in patients undergoing cardiopulmonary bypass with autologous blood predonation were reviewed. Multivariate logistic regression and RECPAM tree-growing analyses were applied to identify the preoperative predictors of allogeneic transfusion in these patients.
Results: Data from 230 patients included in our autologous blood program between 1995 and 1998 were analysed. Patients undergoing complex/reoperative surgical procedures and patients over age 64yr with a low red cell volume (<2070ml) undergoing simple procedures were more likely to require allogeneic red cells. Younger patients with a low red cell volume undergoing simple procedures carried an intermediate risk. Allogeneic transfusion was avoided in 95% of patients undergoing simple procedures when red cell volume > or = 2070ml.
Conclusions: In our institution, complex/reoperative surgery, low red cell volume and increased age are the main factors associated with the need for allogeneic red cell transfusion despite autologous blood predonation. Knowledge of the factors that limit the effectiveness of predonation with respect to allogeneic blood exposure should help clinicians decide which cardiac surgical patients should be included in autologous blood programs.