Transfusion Triggers in Cardiac Surgery

The optimal hemoglobin concentrations for transfusion in the perioperative setting in patients having cardiac surgery have not been established, and red cell transfusion rates for these patients are high. In a recent retrospective study of seven Canadian centres, which included 11,812 cardiac surgical patients, 44% of patients received one or more red cell units, and the range of patients transfused was 28% to 60%. As morbidity and mortality may be dependent on the severity of anemia and administration of transfusions, it is essential to determine at what hemoglobin concentration physicians should be transfusing these patients, particularly because the efficacy of transfusion has not been established. However, as any definitive trial will require thousands of patients, and as there is variability in transfusion practices, preliminary studies need to be completed to ensure the feasibility of adherence to proposed transfusion strategies. This pilot study is the first of two pilot trials designed to address the question of optimum hemoglobin concentrations for transfusion in patients having cardiac surgery prior to undertaking a definitive randomized controlled trial. The purpose of this study is to determine adherence to transfusion strategies.