Hemoglobin thresholds and red blood cell transfusion in adult patients with moderate or severe traumatic brain injuries: A retrospective cohort study

Purpose: We aimed to evaluate the association between transfusion practices and clinical outcomes in patients with traumatic brain injury. Material and methods: We conducted a retrospective cohort study of adult patients with moderate or severe traumatic brain injury admitted to the intensive care unit (ICU) of a level I trauma center between 2009 and 2013. The associations between hemoglobin (Hb) level, red blood cell (RBC) transfusion and clinical outcomes were estimated using robust Poisson models and proportional hazard models with time-dependent variables, adjusted for confounders. Results: We included 215 patients. Sixty-six patients (30.7%) were transfused during ICU stay. The median pre-transfusion Hb among transfused patients was 81 g/L (IQR 67–100), while median nadir Hb among non-transfused patients was 110 g/L (IQR 93–123). Poor outcomes were significantly more frequent in patients who were transfused (mortality risk ratio [RR]: 2.15 [95% CI 1.37–3.38] and hazard ratio: 3.06 [95% CI 1.57–5.97]; neurological complications RR: 3.40 [95% CI 1.35–8.56]; trauma complications RR: 1.65 [95% CI 1.31–2.08]; ICU length of stay geometric mean ratio: 1.42 [95% CI 1.06–1.92]). Conclusions: During ICU stay, transfused patients tended to have lower Hb levels and worse outcomes than patients who did not receive RBCs, after adjustment for confounders.