Packed red blood cell transfusion threshold in traumatic brain injury: a systematic overview of reported studies

Abstract Introduction Low hemoglobin can compromise cerebral oxygen delivery in traumatic brain injury patients with many clinical studies have reviewed blood transfusion practices. The present review was conducted to understand the reporting patterns of hemoglobin threshold to trigger packed red blood cell transfusions in traumatic brain injury patients in reported studies. Methods A systematic literature search of the selected electronic databases was performed. Studies reporting on traumatic brain injury patients, where the trigger levels of hemoglobin to transfuse packed red blood cells were identified, were included in the study. Randomized controlled trials, quasi-randomized controlled studies, and prospective and retrospective observational studies meeting the inclusion criteria were included. The studies excluded were case series, case reports, letters to editors, editorials, comments, animal studies, and studies from non-English literature. Results Of the 249 articles screened, seven were included in the final qualitative synthesis. All the studies were from the West, with 1791 patients, including one study on the pediatric population. All these studies explored Hb threshold values varying from 7 to 10 g/dl in moderate-to-severe traumatic brain injury patients. There was heterogeneity among the studies included, with varied results showing worse outcomes with lower Hb threshold in few studies and no difference or worse complications with transfusion in others. Conclusion Various studies have used different such as “restrictive” or “liberal”; however, determining the optimal threshold level of hemoglobin for blood transfusion remains controversial; hence, it is suggested that there is a need for well-designed prospective studies to identify the safest lower hemoglobin levels in TBI patients.