Association between duration of storage of transfused red blood cells and morbidity and mortality in adult patients: myth or reality?

BACKGROUND: The duration of red blood cell (RBC) storage before transfusion may alter RBC function and, therefore, influence the incidence of complications. STUDY DESIGN AND METHODS: With a computerized literature search from 1983 to 2008, 27 studies reporting the relationship between age of transfused RBCs and physiologic variables or incidence of complications in adult patients were identified. RESULTS: Three studies (one abstract only, two foreign language) were excluded. The 24 remaining studies were grouped according to the patient population: cardiac surgery (eight studies), colorectal surgery (three), intensive care unit (ICU; seven), and trauma (six). The studies were too heterogeneous to allow a formal meta-analysis. Twenty-one of the 24 studies were single-center, and 12 were retrospective. The number of patients was highly variable, ranging from 15 to 6002. In cardiac surgery, two studies reported an increased risk of mortality but had statistical limitations. In colorectal surgery, two studies that addressed the effect on postoperative infections in the same database but with different designs yielded conflicting results. In general ICU patients, two retrospective studies reported a significant correlation between length of RBC storage and microcirculatory alterations or mortality, but the results were not confirmed in subsequent prospective, double-blinded studies. In trauma, five studies reported a correlation between RBC age and development of infection, multiple organ dysfunction, or mortality. CONCLUSIONS: From the currently available published data, it is difficult to determine whether there is a relationship between the age of transfused RBCs and outcome in adult patients, except possibly in trauma patients receiving massive transfusion.