A 57-year-old man has been in the ICU for 10 days with acute respiratory distress syndrome (ARDS) and sepsis due to pneumonia. His hemoglobin level is 7.5 g/dL.
Which of the following statements is MOST correct regarding management of his anemia associated with critical illness?
A. Use of recombinant human erythropoietin (EPO, epoetin alfa) will reduce his need for red-cell transfusionCorrect Answer: D
Anemia is common in ICU patients. Ninety-seven percent of critically ill patients are anemic by day 8. Anemia results from RBC loss from injury, phlebotomy, procedures, etc., and decreased RBC production. Hepcidin plays a central role in iron homeostasis. Its synthesis is upregulated by inflammatory cytokines, resulting in decreased iron absorption and decreased release of iron from body stores creating an iron-deficiency–like state. Decreased renal function and proinflammatory cytokines decrease EPO production.
In a prospective, multicenter, randomized, double-blind, placebocontrolled trial involving 1460 patients, the use of recombinant human EPO (epoetin alfa) to treat anemia in critically ill patients was not associated with decreased red transfusions using a target hemoglobin concentration between 7 and 9 g/dL. In this study, patients who received EPO had a higher rate of thrombotic events if they did not receive prophylactic or therapeutic doses of heparin. Overall mortality was the same between the group that received EPO and the group that received placebo.
The use of iron supplementation is controversial in critically ill patients because it can promote bacterial growth and infection. Hepcidin’s upregulation by inflammatory cytokines may be protective. One multicenter, randomized, placebo-controlled trial of intravenous iron supplementation in critically ill trauma patients showed no difference between groups in hemoglobin concentration, packed red blood cell transfusion requirement, risk of infection, length of stay, or mortality at 14 days. A meta-analysis of five randomized controlled trials involving 665 patients showed iron supplementation did not reduce RBC transfusion. However, the strength of this conclusion is limited by moderate heterogeneity between the studies.
In a study comparing a transfusion threshold of 9 versus 7 g/dL in patients with septic shock, there was no difference in 90-day mortality, rates of ischemic events, or use of life support between the two groups. Patients assigned to the lower transfusion group received fewer transfusions. The Surviving Sepsis guidelines recommend not transfusing RBCs in adults with sepsis until the hemoglobin falls below 7.0 g/dL.
Phlebotomy can result in a daily loss of 40 to 70 mL of blood in a critically ill patient exceeding the basal RBC formation rate of 15 to 20 mL/d under normal conditions. Strategies to minimize blood loss such as use of small volume phlebotomy tubes, point-of-care testing, reinfusion of discard sample from indwelling lines, and reducing the number of laboratory studies obtained can decrease this source of blood loss.
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