Anemia and Blood Transfusion in the Critically Ill Patient

SUMMARY Anemia is common in critically ill patients and results in a large number of red blood cell (RBC) transfusions. Recent data from both the US and Europe confirm that transfusion practice has changed little over the last decade. Between 40 and 50% of all patients admitted to intensive care units (ICU) receive at least one RBC unit and average close to 5 RBC units during their ICU admission. In these patients, extent of anemia is associated with poorer clinical outcomes, however RBC transfusion appears not to improve these outcomes.The anemia of critical illness is a distinct clinical entity characterized by a blunted erythropoietin (EPO) production and abnormalities in iron metabolism identical to what is commonly referred to as the anemia of chronic disease.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 g/dL, and therefore a more conservative approach to RBC transfusion is warranted. Strategies to minimize blood loss and increase the production of RBCs are important in the management of all critically ill patients.