Abstract
Blood transfusion has for years been considered to have obvious clinical benefits and to be a relatively low-risk procedure. Not until the early 1980s did transfusion practices begin to come under systematic scrutiny. Initially, this trend was driven by concern about transfusion-related infection, particularly by human immunodeficiency virus, but advances in transfusion medicine have greatly decreased the risk of transmission of viruses by transfused blood. Now, other concerns — the effects of transfusion on the immune system, transfusion-related acute lung injury, and the age of transfused blood — drive the debate over transfusion practice and have led to methodical examinations . . .