Liberal vs. Restrictive Transfusion in Patients with Moderate and Severe Traumatic Brain Injury: A Secondary Analysis of the RESTRIC Trial, a multicenter, cluster-randomized crossover trial

Introduction   Traumatic brain injury (TBI) is a major cause of morbidity and mortality. However, the impact of transfusion strategy on patients with moderate to severe TBI remains unclear. Thus, we aimed to determine whether transfusion strategies in the acute phase of trauma care influence clinical outcomes in patients with severe trauma and TBI who are at risk for major bleeding. Methods To compare the effect of liberal versus restrictive red blood cell (RBC) transfusion strategies on clinical outcomes in TBI patients, we performed a secondary analysis of the RESTRIC trial, a multicenter, cluster-randomized crossover trial in Japan. We assessed liberal (10–12 g/dL) and restrictive (7–9 g/dL) RBC transfusion strategies in adult trauma patients at risk for major bleeding, focusing on patients with head abbreviated injury score (AIS) ≥ 2. Logistic regression analysis adjusted for age, sex, mechanism of trauma, injury severity score, shock on arrival (defined as systolic blood pressure under 90 mmHg), Glasgow Coma Scale score, and the use of antithrombotic agent was performed. The primary outcome was the proportion of favorable neurological outcomes at discharge, defined as Glasgow Outcome Scale (GOS) scores of 4 or 5. We conducted the same analysis in subgroups stratified by TBI severity (moderate: AIS 2–3; severe: AIS 4–5). Results After omitting patients according to exclusion criteria, 153 RESTRIC trial patients were included in this study (liberal group: 68; restrictive group 85). The proportion of favorable GOS scores was 26.5% (18/68) in the liberal group and 30.6% (26/85) in the restrictive group; adjusted logistic regression did not show a significant difference (OR 1.06, 95% CI 0.44–2.56, p = 0.90). We also observed this trend in our subgroup analysis (moderate; OR 1.39, 95% CI 0.47–4.09, p = 0.55; severe: OR 0.68, 95% CI 0.10–4.84, p = 0.70). Conclusions In this secondary analysis of the RESTRIC trial focusing on patients with severe trauma and TBI at risk for major bleeding, transfusion strategies in the acute phase of trauma care were not associated with favorable GOS at discharge.