Aetiology and outcome of massive transfusion in two large London teaching hospitals over a 3-year period (2012-2014).

OBJECTIVES: The objectives of this study were to determine: (i) the incidence of massive transfusion (MT) (defined as transfusion of ≥5 red-blood-cell (RBC) units within 4 h, and/or ≥10 RBC units within 24 h of bleeding) over a 3-year period; (ii) the cause, and mortality rate of patients who received MT (from any cause); and (iii) the risk factors for death.

BACKGROUND: MT can occur in different clinical settings, yet little is known about its epidemiology/clinical outcomes.

METHODS: Data was extracted using transfusion laboratory information management system (LIMS) and patients' electronic databases.

RESULTS: We identified 701 episodes (incidence 1.7 per 1000 admissions [95% confidence interval (CI): 1.6-1.9], belonging to 678 patients (225 females and 453 males, median age 61). Main causes of MT were cardiac surgery (35%), trauma (28%), medical (10%) and vascular surgery (9%). The overall mortality was 32%, and the median number of days spent in hospital was 14 and 2 for those who survived and those who died, respectively. Multivariable analysis showed that cardiac surgery was associated with 56% (95% CI: 9-78%) lower odds of death compared to other surgery, and transfusion of 10-14 RBC and >15 RBC units (compared with 5-9 RBC units) were associated with 2.1 (95% CI: 1.4-3.3) and 9.9 (95% CI: 4.6-21.1) times higher odds of dying, respectively.

CONCLUSION: In-hospital morbidity and mortality of MT is high. Future research should focus on unifying the definition of MT, and early identification of the MT markers in order to improve outcomes.