Age of blood and survival after massive transfusion

Background: Massive transfusion is the clinical scenario where the presumed adverse effects of stored blood are expected to be more evident because the whole patient's blood volume is replaced by stored blood.

Objective: To analyse the association between age of transfused red blood cells (RBC) and survival in massively transfused patients.

Methods: In this retrospective study, clinical and transfusion data of all consecutive patients massively transfused between 2008 and 2014 in a large, tertiary-care hospital were electronically extracted from the Transfusion Service database and the patients' electronic medical records. Prognostic factors for in-hospital mortality were investigated by multivariate logistic regression.

Results: A total of 689 consecutive patients were analysed (median age: 61 years; 65% males) and 272 died in-hospital. Projected mortality at 2, 30, and 90 days was 21%, 35% and 45%, respectively. The odds ratio (OR) for in-hospital mortality among patients who survived after the 2nd day increased with patient age (OR: 1.037, 95% CI: 1.021-1.054; per year P<0.001), with the number of RBC unit transfused in the first 48hours (OR: 1.060; 95% CI: 1.038-1.020 per unit; P<0.001), and the percentage of such RBC stored for more than 28 days (1.010, 95% CI: 1.005-1.018 per percent point; P=0.01).

Conclusion: Mortality after massive transfusion was associated with a higher proportion of old RBCs transfused in the first 48hours. Other factors associated with poor prognosis were older patient's age and larger volumes of transfused RBCs.