Anaemia is a common finding in critically ill patients. There are often multiple causes. Obvious causes include surgical bleeding and gastrointestinal haemorrhage but many patients have no overt bleeding episodes. Phlebotomy can be a significant source of blood loss. In addition, critically ill patients have impaired erythropoiesis as a consequence of blunted erythropoietin production and direct inhibitory effects of inflammatory cytokines. The ability of a patient to tolerate anaemia depends on their clinical condition and the presence of any significant co-morbidity; maintenance of circulating volume is of paramount importance. There is no universal transfusion trigger. Current guidelines for critically ill and perioperative patients advise that at Hb values <70 g/L red blood cell transfusion is strongly indicated and at Hb values >100 g/L transfusion is unjustified. For patients with Hb values in the range 70 to 100 g/L the transfusion trigger should be based on clinical indicators. Most stable critically ill patients can probably be managed with a Hb concentration between 70 and 90 g/L. Uncertainties exist concerning the most appropriate Hb concentration for patients with significant cardio-respiratory disease.

中文翻译：

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重症患者贫血和红细胞输血。

贫血是重症患者的常见发现。通常有多种原因。明显的原因包括手术出血和胃肠道出血，但是许多患者没有明显的出血发作。放血可能是失血的重要原因。另外，重症患者由于促红细胞生成素生成减弱和炎症细胞因子的直接抑制作用而导致促红细胞生成受损。患者耐受贫血的能力取决于他们的临床状况和任何明显的合并症；维持循环量至关重要。没有通用的输血触发器。当前针对重症和围手术期患者的指南建议在Hb值<70 g / L时强烈建议输血，而Hb值> 100 g / L的输血是不合理的。对于Hb值在70至100 g / L范围内的患者，输血触发应基于临床指标。最稳定的危重病人可以控制Hb浓度在70至90 g / L之间。对于患有严重的心肺疾病的患者，最合适的血红蛋白浓度存在不确定性。