Blood transfusion: friend or foe.

The effectiveness of transfusions is often compromised by adverse reactions. Common transfusion reactions (hemolytic transfusion reactions, transfusion-related acute lung injury, transfusion-associated circulatory overload, transfusion-related immunomodulation) are reviewed, including pathogenesis, clinical and laboratory manifestations, and treatment. In addition, artificial blood substitutes are discussed as a way to mitigate the risk of transfusion-related morbidity and mortality.