Iron supplementation in the intensive care unit: when, how much, and by what route?

Derangements of iron metabolism may be present in critically ill patients who develop anemia during a stay in the intensive care unit. Iron supplementation may be appropriate, especially if an underlying nutritional disorder is present. It may be even more critical to replace iron when erythropoietin therapy is used because of the consumption of iron stores that occurs during heme synthesis. Iron therapy is not without risks, and controversy persists regarding the potential for iron overload and infections. Clinical trials that define the optimal dose, route, and timing of iron administration in critically ill patients are lacking. However, studies of iron supplementation in chronic kidney disease, pregnancy, and anemia of prematurity may provide some guidance about approaches to treatment. Clinical evidence and limitations that can assist clinicians in managing iron therapy in the intensive care unit are presented.