High Fresh Frozen Plasma to Red Blood Cell Ratio and Survival Outcomes in Blunt Trauma.

Importance: Current trauma-care protocols advocate early administration of fresh frozen plasma (FFP) in a ratio close to 1:1 with red blood cells (RBCs) to manage trauma-induced coagulopathy in patients with severe blunt trauma. However, the benefits of a higher FFP to RBC ratio have not yet been established.

Objective: To investigate the effectiveness of a high FFP to RBC transfusion ratio in the treatment of severe blunt trauma and explore the nonlinear relationship between the ratio of blood products used and patient outcomes.

Design, setting, and participants: This was a multicenter cohort study retrospectively analyzing data from the Japan Trauma Data Bank, including adult patients with severe blunt trauma without severe head injury (Injury Severity Score ≥16 and head Abbreviated Injury Scale <3) between 2019 and 2022.

Exposures: Patients were categorized into 2 groups based on the ratio of FFP to RBC: the high-FFP group (ratio >1) and the low-FFP group (ratio ≤1).

Main outcomes and measures: All-cause in-hospital mortality was the primary outcome. Additionally, the occurrence of transfusion-related adverse events was evaluated.

Results: Among the 1954 patients (median [IQR] age, 61 [41-77] years; 1243 male [63.6%]) analyzed, 976 (49.9%) had a high FFP to RBC ratio. Results from logistic regression, weighted by inverse probability treatment weighting, demonstrated an association between the group with a high-FFP ratio and lower in-hospital mortality (odds ratio, 0.73; 95% CI, 0.56-0.93) compared with a low-FFP ratio. Nonlinear trends were noted, suggesting a potential ceiling effect on transfusion benefits.

Conclusions and relevance: In this cohort study, a high FFP to RBC ratio was associated with favorable survival in patients with severe blunt trauma. These outcomes highlight the importance of revising the current transfusion protocols to incorporate a high FFP to RBC ratio, warranting further research on optimal patient treatment.