This was a three-year retrospective study that included 196 severely injured trauma patients who received red blood cell (RBC) transfusions. The authors tested the hypothesis that the storage time of transfused RBCs was associated with an increased rate of nosocomial infections. A multivariate analysis was performed adjusting for disease severity (APACHE 16, ISS 25) and number of transfused units. The authors found that each RBC unit stored for >15 days increased the rate of nosocomial pneumonia (odd ratio 1,03).
The study is interesting because the two leading causes – number of transfused units and disease severity – confounding the relationship between the length of storage of the transfused erythrocytes and the development of nosocomial infections, were conveniently adjusted for. However, only 120 were included and error type 1 could be present. Further studies with a randomized, controlled design are needed.

– Santiago Ramón Leal-Noval