What Is the Optimal Transfusion Threshold After Cardiac Surgery?

The optimal hemoglobin threshold for transfusion after surgical procedures is a longstanding controversy. Observational studies of patients undergoing cardiac surgery have suggested worse outcomes with liberal transfusion thresholds (i.e., transfusion at higher hemoglobin levels), but randomized trials in patients with various indications have shown no meaningful differences. To test the hypothesis that a more-restrictive threshold would result in lower postoperative morbidity and cost, researchers randomized 2003 patients undergoing elective cardiac surgery whose postoperative hemoglobin level dropped below 9 g/dL to either a liberal transfusion hemoglobin threshold (9 g/dL) or a relatively restrictive threshold (7.5 g/dL). All patients re…