Cresting Mortality: Defining a Plateau in Ongoing Massive Transfusion

BACKGROUND: Blood-based balanced resuscitation is a standard of care in massively bleeding trauma patients. No data exists as to when this therapy no longer significantly affects mortality. We sought to determine if there is a threshold beyond which further massive transfusion will not affect in-hospital mortality. METHODS: The Trauma Quality Improvement database was queried for all adult patients registered between 2013 and 2017 who received at least one unit of blood (PRBC) within 4 hours of arrival. In-hospital mortality was evaluated based on the total transfusion volume (TTV) at 4 and 24 hours in the overall cohort (OC) and in a balanced transfusion cohort (BC), composed of patients who received transfusion at a ratio of 1:1-2:1 PRBC-to-plasma. A bootstrapping method in combination with multivariable Poisson regression (MVR) was used to find a cutoff after which additional transfusion no longer affected in-hospital mortality. MVR was used to control for age, sex, race, highest abbreviated injury score in each body region, comorbidities, advanced directives limiting care, and the primary surgery performed for hemorrhage control. RESULTS: The OC consisted of 99,042 patients of which 28,891 and 30,768 received a balanced transfusion during the first 4 and 24 hours, respectively. The mortality rate plateaued after a TTV of 40.5 units (95% CI, 40-41) in the OC at 4 hours and after a TTV of 52.8 units (95% CI, 52-53) at 24 hours following admission. In the BC, mortality plateaued at a TTV of 39 units (95% CI, 39-39) and 53 units (95% CI, 53-53) at 4- and 24-hours following admission, respectively. CONCLUSION: Transfusion thresholds exist beyond which ongoing transfusion is not associated with any clinically significant change in mortality. These TTVs can be used as markers for resuscitation timeouts in order to assess the plan of care moving forward. LEVEL OF EVIDENCE: Level V, prognostic and epidemiological