Safe Application of a Restrictive Transfusion Protocol in Moderate-risk Patients Undergoing Cardiac Operations

Background: Perioperative red blood cell transfusion is associated with adverse outcomes after cardiac operations. Although restrictive transfusion protocols have been developed, their safety and efficacy are not well demonstrated, and considerable variation in transfusion practice persists. We report our experience with a restrictive transfusion protocol.

Methods: We analyzed the outcomes in 409 patients undergoing cardiac operations enrolled in a trial conducted at 30 centers worldwide. Blood products were administered on the basis of a transfusion algorithm applied across all centers, with a restrictive transfusion trigger of hemoglobin less than or equal to 6 g/dL. Transfusion was acceptable but not mandatory for hemoglobin 6 to 8 g/dL. For hemoglobin 8 to 10 g/dL, transfusion was acceptable only with evidence for end-organ ischemia.

Results: The patient population was moderately complex, with 20.5% having combined procedures and 29.6% having nonelective operations. The mean EuroSCORE for the population was 4.3, which predicted a substantial incidence of morbidity and mortality. Actual outcomes were excellent, with observed mortality of 0.49% and rates of cerebrovascular accident, myocardial infarction, and acute renal failure 1.2%, 6.1%, and 0.98%, respectively. The frequency of red blood cell transfusion was 33.7%, which varied significantly by center. Most transfusions (71.9%) were administered for hemoglobin 6 to 8 g/dL; 21.4% were administered for hemoglobin 8 to 10 g/dL with evidence for end-organ ischemia; 65.0% of patients avoided allogeneic transfusion altogether.

Conclusions: A restrictive transfusion protocol can be safely applied in the care of moderate-risk patients undergoing cardiac operations. This strategy has significant potential to reduce transfusion and resource utilization in these patients, standardize transfusion practices across institutions, and increase the safety of cardiac operations.