Transfusion practice and nosocomial infection: assessing the evidence

To evaluate recent literature describing the potential relation between transfusion practice in the intensive care unit and the subsequent risk for nosocomial infection.

Multiple studies have documented that patients in the intensive care unit often receive transfusions of packed red blood cells while in the intensive care unit. Although the safety of the blood supply has increased substantially over the last decade, nosocomial infection is emerging as an unappreciated potential consequence of transfusion. Research now suggests that transfusion alters the host's immune system. Clinically, this may lead to relative immunosuppression and result in nosocomial infection. Supporting this hypothesis, an association between infection and transfusion has been shown in various settings and for several different types of infections. In both postoperative and medical intensive care unit subjects, administration of packed red blood cell consistently raises the risk for infection. Similarly, transfusion rates correlate with two major nosocomial complications in the intensive care unit: pneumonia and bloodstream infection. Proof of causation remains elusive because of study design issues. Nonetheless, the weight of the evidence favors adding nosocomial infection to the list of potential risks related to packed red blood cell transfusion.

Packed red blood cell transfusion may substantially increase the risk for nosocomial infection. The likely link between transfusion practice and nosocomial infection should factor into the provider's decision when determining when to transfuse.