Transfusion Practices in Traumatic Brain Injury: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Summary

This meta-analysis of five RCTs in TBI (n=1,533) found no mortality differences between liberal and restrictive transfusion strategies, but liberal transfusion increased ARDS risk (RR 1.78) and units transfused while potentially improving favorable neurologic outcomes after sensitivity analysis. The authors advocate reconsidering a 9 g/dL threshold, balancing neurologic benefit against pulmonary complications.

Key Findings

• Across 5 RCTs (n=1,533), no significant differences in hospital, ICU, or follow-up mortality between liberal and restrictive transfusion strategies.
• Liberal transfusion increased ARDS incidence (RR 1.78; 95% CI, 1.06-2.98) and units transfused (MD 2.62).
• Favorable Glasgow Outcome Scale improved in leave-one-out sensitivity analysis (RR 1.24; 95% CI, 1.06-1.45), though not in the primary pooled estimate.

Clinical Implications

When considering a 9 g/dL hemoglobin threshold in TBI, clinicians should monitor for ARDS and apply lung-protective strategies if liberal transfusion is used. Institutional guidelines may need updates to balance neurologic outcomes and pulmonary risk.

Limitations

• Limited number of RCTs and potential heterogeneity across protocols and thresholds
• Lack of individual patient data precludes nuanced subgroup analyses and mechanistic inference for ARDS

Future Directions

Conduct pragmatic RCTs testing a 9 g/dL threshold with ARDS as a prespecified safety endpoint and integrate lung-protective measures; explore patient-level modifiers (age, severity, hypoxemia).