A Retrospective Study of Ultramassive Transfusion in Trauma Patients: Is There a Value After Which Additional Transfusions Are Futile?

Background: Hemorrhage is a leading cause of preventable mortality in trauma. During times of blood shortages, it may be prudent to consider a transfusion threshold during massive transfusion after which additional transfusions are futile due to nonsurvivability. The main objective of this study is to examine outcomes associated with ultramassive transfusion (UMT; defined as ≥20 units of red blood cells [RBC] within 24 hours) and determine if there is a threshold beyond which additional transfusion efforts should cease.

Methods: We performed a retrospective (2016-2022) analysis of adult trauma patients (≥ 18 years old) who underwent surgery and received blood products within 24 hours of admission at 7 US Level I trauma centers. We compared patients who received UMT and patients who received <20 units RBC and evaluated the effects of various amounts of blood products on mortality, length of stay (LOS), mechanical ventilation (MV), and complications. Segmented logistic regression analysis was performed to determine if there is a "plateau" effect of increasing RBC units on mortality.

Results: Of 3248 patients included, 2913 (89.7%) received <20 RBC units within 24 hours, and 333 (10.3%) received ≥20 RBC units within 24 hours. Patients receiving UMT had increased 24-hour mortality (risk ratio [RR] 6.00, 95% confidence interval [CI], 4.79-7.52, P < .001) and index hospitalization mortality (RR 3.99 [3.34-4.75], P < .001). These patients also more often developed complications (RR 1.67 [1.44-1.94], P < .001) and multiple organ failure (RR 2.78 [2.20-3.52], P < .001). Compared to those receiving 20 to 29 RBC units, those receiving 30 to 44 RBC units had statistically similar associated risk of death (RR 1.32 [0.93-1.87], P = .12); however, those receiving ≥45 RBC units had an increased associated risk of death (RR 1.59, [1.12-2.25], P = .009), and additional transfusion beyond this point did not improve the probability of survival.

Conclusions: In this study, patients who received UMT had higher mortality and worse outcomes than those who received fewer units. However, this study did not identify a threshold beyond which all patients died and therefore cannot justify implementing a limit on the number of RBC units transfused based on these data alone.