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 exist 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 (packed red blood cell) within 4 hours of arrival. In-hospital mortality was evaluated based on the total transfusion volume (TTV) at 4 hours and 24 hours in the overall cohort (OC) and in a balanced transfusion cohort, composed of patients who received transfusion at a ratio of 1:1 to 2:1 packed red blood cell to plasma. A bootstrapping method in combination with multivariable Poisson regression was used to find a cutoff after which additional transfusion no longer affected in-hospital mortality. Multivariable Poisson regression was used to control for age, sex, race, highest Abbreviated Injury Scale 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 hours and 24 hours, respectively. The mortality rate plateaued after a TTV of 40.5 units (95% confidence interval [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 balanced transfusion cohort, mortality plateaued at a TTV of 39 units (95% CI, 39-39) and 53 units (95% CI, 53-53) at 4 hours 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 to assess the plan of care moving forward.

Level of evidence: Prognostic and epidemiological, Level III.