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 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 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.多种因素可影响重型颅脑损伤的预后，其中包括患者的血红蛋白水平。临床常面临关于红细胞输注（Red Cell Blood Transfusion, RCBT）时机的血红蛋白阈值选择争议。为系统回顾相关文献以明确基于血红蛋白水平的诊疗方案的临床价值，本研究遵循PRISMA声明（PRISMA statement）构建检索策略，采用医学主题词（Medical Subject Heading, MeSH）术语及描述词结合布尔运算符进行文献检索。本研究对纳入文献的全文进行研读，对接受红细胞输注的患者术后3~6个月的结局指标进行评估，最终共纳入4篇文献开展荟萃分析。与以血红蛋白<10g/dL为阈值的红细胞输注策略相比，以血红蛋白<7g/dL为阈值的红细胞输注并未增加患者的死亡风险。较低血红蛋白阈值下的红细胞输注与不良神经预后（格拉斯哥预后评分4~5分）无显著关联，反而与更优的预后（格拉斯哥预后评分1~3分）相关，且该关联具有统计学显著性。异基因红细胞输注与更差的神经预后相关，且现有研究中创伤性脑损伤（Traumatic Brain Injury, TBI）患者的红细胞输注血红蛋白阈值差异较大。限制性红细胞输注策略或可应用于中重度创伤性脑损伤患者，但贫血诱导的脑损伤风险，以及红细胞输注本身固有的风险与并发症，仍需进一步研究。