In search of the transfusion trigger.

Red blood cell transfusions are used commonly in orthopaedic surgery and cost billions of dollars annually. The goals of transfusion are to reduce mortality and morbidity and improve functional status that result from anemia and inadequate O2 delivery. Risks of infections from transfusion are low and continue to decline, but evidence is growing that red cell transfusions are immunosuppressive and predispose patients to postoperative infections. However, there actually are very little data on when transfusion is indicated. Observational data suggest that transfusion does not reduce mortality in patients with preoperative or postoperative hemoglobin levels 8 g/dL or greater, although no conclusions could be drawn about the effect of transfusion in patients with hemoglobin 8 g/dL or less. Large, well performed randomized clinical trials are needed to establish the efficacy of transfusion. Until better data are available, orthopaedic surgeons will have to rely on clinical judgement in decisions regarding transfusions. Using a higher transfusion threshold in patients with cardiovascular disease is recommended.