Anemia of critical illness, a commonly encountered clinical situation, is hematologically similar to that of chronic anemia, except that the onset is generally sudden. The etiology of ICU anemia is usually multifactorial, occurring as a consequence of direct inhibitory effects of inflammatory cytokines, erythropoietin deficiency, blunted erythropoietic response, blood loss, nutritional deficiencies, and renal insufficiency.Iron is frequently prescribed in the ICU to help in the erythropoiesis process. However, the relationship between iron and infections remains to be a concern.1
Previous studies have identified the role of enteral iron supplementation in reducing packed RBC transfusions compared to placebo. However the fact that ICU patients cannot tolerate enteral medications and because of the impact of inflammation on oral absorption, IV iron supplementation is recommended.2,3
This new study that was just published in Critical Care Medicine journal aimed to evaluate the efficacy of IV iron supplementation in anemic critically ill trauma patients. It is a multicenter, randomized, single-blind, placebo-controlled study in 4 trauma centers.4 Eligible patients include those with a primary diagnosis of trauma; anemia (latest hemoglobin concentration <12 gm/dL); age >18 years old; less than or equal to 72 hours of admission; expected ICU length of stay >5 days. Patients were randomized to either iron sucrose of 100 mg IV or placebo three times a week for 2 weeks. The study was blinded to research team but not to patient or healthcare provider administering the iron formulation. Subjects were followed for 42 days or until hospital discharge, whichever occurred first. The decision to give blood transfusion was made by the attending intensivist, ICU protocols were predetermined at a transfusion threshold of <7g/dL in the absence of shock or acute coronary syndrome.
A total of 150 patients were randomized, baseline iron markers confirmed the presence of functional iron deficiency. In addition, baseline characteristics were not different between the two groups except that the iron group had more males (p=0.03) and had a trend toward higher APACHE II score (p=0.1). For the subgroup of patients that received all the six doses of study drug, the serum ferritin concentration increased significantly for the iron group compared to the placebo group on day 7 (808 ng/ml vs. 457 ng/ml, p<0.01) and day 14 (1,046 ng/ml vs. 551.5 ng/ml, p<0.01). However, there was no significant difference between the two group in terms of transferrin saturation, hemoglobin saturation, packed RBC transfusion requirement, infection rate, and mortality.
The authors concluded that iron supplementation did not impact functional iron deficiency or packed RBC transfusion and therefore cannot be recommended in anemic, critically ill trauma patients. This study is limited by the fact that its single-blinded, the variability of practice between centers, and the fact that enrollment was only 75% of the target sample size of 200. It is crucial that more studies are published to reach a consensus about iron supplementation in critically ill patients.
1. DeBellis RJ. Anemia in critical care patients: Incidence, etiology, impact, management, and use of treatment guidelines and protocols. Am J Health Syst Pharm. 2007;64:S14–21; quiz S28
2. Pieracci FM, Henderson P, Rodney JR, et al. Randomized, double-blind, placebo-controlled trial of effects of enteral ...