Hemoglobin levels as a transfusion criterion in moderate to severe traumatic brain injury: a systematic review and meta-analysis

Several factors can influence the outcome of severe head injuries including the patient's hemoglobin levels. There has often been a dilemma regarding levels of hemoglobin at which red cell blood transfusion (RCBT) should be performed.To systematically review the literature to determine the usefulness of management protocols that have hemoglobin levels <10 g/dL vs <7 g/dL as an RCBT criterion.Following the PRISMA statement, the search was constructed using terms and descriptors of the Medical Subject Heading (MeSH), combined with Boolean operators. Full text of these articles was studied, and outcome measures at 3-6 months were considered for patients who were given a RCBT at <10 g/dL or at 7 g/dL hemoglobin levels.A total of 4 articles were found suitable for inclusion in the meta-analysis. RCBT below 7 g/dL was not associated with an increased risk of mortality as compared to RCBT using the value of less than 10 g/dL. RCBT at lower levels of hemoglobin was also not associated with a poor neurological outcome (GOS 4-5) but rather RCBT at lower levels lead to better outcomes (GOS 1-3) and the association was significant.Allogenic RCBT was associated with poorer neurological outcomes, within a wide range of reported differences in the hemoglobin threshold to decide for RCBT in TBI patients. Restrictive RCBT strategy may be useful in moderate to severe TBI cases although the risk of anemia-induced cerebral injury needs further investigation regarding the risks and complications inherent to RCBT.