Anaemia and red blood cell transfusion in the critically ill patient.
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.
McLellan
S A
SA
University Department of Anaesthetics, Critical Care and Pain Medicine, Royal Infirmary of Edinburgh, Edinburgh EH3 9YW, UK. stu.mclellan@ed.ac.uk
McClelland
D B L
DB
Walsh
T S
TS
D000740:Anemia / Q000209:etiology* / Q000503:physiopathology / Q000628:therapy*; D016638:Critical Illness; D017707:Erythrocyte Transfusion / Q000009:adverse effects / Q000592:standards*; D004920:Erythropoiesis / Q000187:drug effects / Q000502:physiology; D004921:Erythropoietin / Q000627:therapeutic use; D006801:Humans; D011994:Recombinant Proteins
D011994:Recombinant Proteins; D004921:Erythropoietin