Effects of transfusing older red blood cells on patient outcomes in critical illness: a retrospective cohort study

Abstract

Abstract Randomised controlled trials have demonstrated critically ill patients do not benefit from receiving fresh (<7 days old) packed red blood cells (pRBCs), however there is limited evidence regarding transfusion with pRBCs nearing expiry (35-42 days). In this retrospective observational study, we analysed data obtained from 7-years of centralised electronic medical records (2007–2013), sourced from hospitals in the Australian state of Queensland, to investigate whether transfusion with pRBCs nearing expiry contributed to increased morbidity and mortality in critically ill patients. 10,350 critically ill adults (>12 years) patients transfused ≥1 unit of non-irradiated pRBCs (64,594 pRBCs units transfused) were included in this study. Receiving at least 1-unit pRBCs ≥35 days old was associated with increased mortality (OR 1.21 [95% CI 1.06–1.38]; p=0.005), decreased discharge to usual residence (OR 0.81 [95% CI 0.73–0.89]; p<0.0001) and increased hospital LOS (Estimate 2.55 [95% CI 1.60–3.49]; p<0.0001). There was also association with increased sepsis (OR 1.27 [95% CI 1.13–1.42]; p<0.0001) and delirium (OR 1.25 [95% CI 1.06–1.49]; p=0.01).Transfusion of ≥1-unit pRBCs ≥35 days old was associated with evidence of increased mortality and morbidity in critically ill patients. Further prospective studies are required to validate findings and overcome limitations of retrospective analysis.