RCT: Liberal Transfusion Strategy Reduced Unfavorable Neurological Outcomes in Acute Brain Injury
12 Oct, 2024 | 11:01h | UTCBackground: Patients with acute brain injury frequently develop anemia, and the optimal hemoglobin threshold for red blood cell transfusion in this population remains uncertain. Previous studies have shown conflicting results regarding the benefits of liberal versus restrictive transfusion strategies on neurological outcomes.
Objective: To determine whether a liberal transfusion strategy (hemoglobin threshold <9 g/dL) reduces the occurrence of unfavorable neurological outcomes at 180 days compared to a restrictive strategy (hemoglobin threshold <7 g/dL) in patients with acute brain injury.
Methods: The TRAIN trial, a multicenter, phase 3, randomized clinical trial, was conducted across 72 ICUs in 22 countries. It included patients with traumatic brain injury, aneurysmal subarachnoid hemorrhage, or intracerebral hemorrhage, who had hemoglobin levels below 9 g/dL within the first 10 days post-injury. Participants were randomized to a liberal strategy (transfusion triggered by hemoglobin <9 g/dL) or a restrictive strategy (transfusion triggered by hemoglobin <7 g/dL), with primary outcomes measured by the occurrence of an unfavorable neurological outcome, defined by a Glasgow Outcome Scale Extended score of 1-5 at 180 days.
Results: Among 820 patients who completed the trial (mean age 51 years; 45.9% women), 806 had data on the primary outcome (393 liberal, 413 restrictive). The liberal group received a median of 2 units of blood (IQR, 1–3), while the restrictive group received a median of 0 units (IQR, 0–1), with an absolute mean difference of 1.0 unit (95% CI, 0.87–1.12 units). At 180 days, 62.6% of patients in the liberal group had an unfavorable neurological outcome compared to 72.6% in the restrictive group (absolute difference –10.0%; 95% CI, –16.5% to –3.6%; adjusted relative risk 0.86; P = .002). The effect was consistent across prespecified subgroups. Cerebral ischemic events were lower in the liberal group (8.8% vs 13.5%; relative risk 0.65; 95% CI, 0.44–0.97). No significant differences were observed in 28-day survival or other secondary outcomes.
Conclusions: In patients with acute brain injury and anemia, a liberal transfusion strategy resulted in a lower rate of unfavorable neurological outcomes at 180 days compared to a restrictive strategy.
Implications for Practice: A liberal transfusion threshold of 9 g/dL may improve neurological outcomes in patients with acute brain injury by reducing cerebral ischemic events. Clinicians should consider adopting a higher hemoglobin threshold for transfusion in this population, weighing the benefits against potential risks associated with transfusions, such as infection or lung injury.
Study Strengths and Limitations: Strengths include the large, multicenter international design and blinding of outcome assessors. Limitations involve the open-label nature, potential detection bias in assessing cerebral ischemic events, lack of standardized neuroprognostication, and incomplete assessment of concomitant interventions.
Future Research: Further studies are needed to confirm these findings in specific subgroups of acute brain injury, to explore optimal transfusion strategies, and to assess long-term outcomes and potential risks associated with liberal transfusion thresholds.