Benefit of balance? Odds of survival by unit transfused: Retrospective analysis of the ACS-TQIP database

The critical blood shortage in January 2022 threatened the availability of blood. Utility of transfusion per unit was reported in a previous study, revealing patients receiving balanced transfusion are more likely to die after 16 units of packed red blood cells. We aimed to validate this study using a larger database.

Retrospective analysis utilizing the American College of Surgeons Trauma Quality Improvement Program was performed. Trauma patients aged ≥16 receiving transfusion within 4 hours of arrival were included and excluded if they died in the emergency department, received <2 units of packed red blood cells, did not receive fresh frozen plasma, or were missing data. Primary outcome was mortality. Subgroups were balanced transfusion if receiving ≤2:1 ratio of packed red blood cells:fresh frozen plasma, and unbalanced transfusion if >2:1 ratio.

A total of 17,047 patients were evaluated with 28% mortality (4,822/17,408). Multivariable logistic regression identified advancing age (odds ratio 1.03 95% confidence interval 1.03-1.04), higher ISS (odds ratio 1.04, 95% confidence interval 1.03-1.04), and lower GCS (odds ratio 0.82, 95% confidence interval 0.82-0.83) as risk factors for mortality. Protective factors were balanced transfusion (odds ratio 0.81 95% confidence interval 0.71-0.93), male sex (odds ratio 0.90, 95% confidence interval 0.81-0.99), and blunt mechanism (odds ratio 0.74, 95% confidence interval 0.67-0.81). At 11 units of packed red blood cells, balanced transfusion patients were more likely to die (odds ratio 0.88, 95% confidence interval 0.80-0.98). Balanced transfusion patients survived at a higher rate for each unit of packed red blood cells, between 6 and 23 units of packed red blood cells.

Mortality increases with each unit of packed red blood cell transfused. At 11 units of packed red blood cells, mortality is the more likely outcome. Balanced transfusion improves the chance of survival through 23 units of packed red blood cells.