In this systematic review, Sowers et al. investigated the impact of the age of stored red blood cells (RBCs) on mortality in patients with traumatic injuries requiring transfusion of blood products. The objective was to identify and describe the available literature on the use of older vs. newer RBCs in trauma patients. PubMed, Embase, Lilac and the Cochrane Database were searched for published studies reporting storage age of transfused RBCs and patient mortality in adult trauma patients.
Seven eligible studies totaling 6,780 patients were identified (three studies from the same institution included a total 5,084 patients). All seven studies were retrospective single-centre cohort studies conducted in the US and published between 2005 and 2010. Five studies used ≤14 days as definition for new RBCs and four studies used >14 days as definition for old RBCs. The remaining studies used different definitions. The studies differed considerably with regard to the use of leucoreduced blood or not and with regard to the blood volume transfused.
Four of the seven studies reported that transfusion of older RBCs was independently associated with increased mortality, whereas 3 studies did not observe any increase in trauma patient mortality with the use of older versus newer RBCs. Furthermore, three studies found an association between transfusion of older RBCs and adverse patient outcomes.
Given that the seven studies varied considerably in design, volumes of blood transfused and definitions applied for old and new RBCs, the authors conclude that the impact of RBC storage on mortality in trauma patients is inconclusive and they call for a properly conducted clinical investigation.
This review provides a nice presentation of the literature on this topic despite the lack of conclusions other than the need to conduct further studies.
– Sisse Rye Ostrowski