Clinical Pulmonary Medicine 2003; 10(4):219-225

Anemia, Blood Transfusion, and Erythropoietin in the Critically Ill

Howard L. Corwin, MD; Marcus D. Hampers, MD; Stephen D. Surgenor, MD

Critically ill patients receive an extraordinarily large number of blood transfusions. Between 40% and 50% of all patients admitted to intensive care units (ICUs) receive at least one red blood cell (RBC) unit and average close to five RBC units during their ICU admission. For the critically ill patient, the risk of a blood transfusion-transmitted infection is not the major concern. What is of more consequence is the accumulating evidence that blood transfusion has profound negative effects on the immune system. On the other hand, there is little evidence that "routine" transfusion of stored allogeneic RBCs is beneficial to critically ill patients. It is clear that most critically ill patients can tolerate hemoglobin levels as low as 7 mg/dL, and therefore a more conservative approach to RBC transfusion is warranted. The anemia of critical illness is a distinct clinical entity characterized by a blunted erythopoietin (EPO) production and abnormalities in iron metabolism identical to what is commonly referred to as the anemia of chronic disease. As such, the bone marrow in many of these patients responds to the administration of exogenous EPO, in spite of their critical illness. The efficacy of perioperative recombinant human EPO (rHuEPO) has been demonstrated in a variety of elective surgical settings. Similarly, in critically ill patients with multiple organ failure, r-HuEPO therapy will also stimulate erythropoiesis. In a randomized, placebo-controlled trial, therapy with rHuEPO resulted in a significant reduction in RBC transfusions. Despite receiving fewer RBC transfusions, patients in the rHuEPO group had a significantly greater increase in hematocrit.

Key words: Blood transfusion; Erythropoietin; Transfusion risks; Transfusion practice

From the Section of Critical Care Medicine, Department of Anesthesiology, Dartmouth Hitchcock Medical Center, Dartmouth Medical School, Lebanon, NH USA.

Address correspondence to: Howard L. Corwin, MD, One Medical Center Drive, Lebanon, NH 03756. Address e-mail to: howard.l.corwin@hitchcock.org