LEARNING OBJECTIVESOn completion of this article, the reader should be able to:1. Identify the potential etiologies of anemia in critically ill infants with bronchiolitis.2. Conclude that erythropoietin therapy improves reticulocyte count but does not reduce transfusion requirements in infants with bronchiolitis.3. Conclude that the effiacy of erythropoietin therapy in treating anemia varies in the ICU depending on the underlying cause of the anemia and co-morbid condition.The authors have disclosed that they have no financial relationships with commercial companies pertaining to this educational activity.Visit thePediatric Critical Care MedicineOnline website (www.pccmjournal.com) for information on obtaining continuing medical education credit.ObjectiveCritically ill children with bronchiolitis often require red blood cell transfusions. Anemia normally results in increased circulating erythropoietin concentrations; however, critical illness has been associated with a blunted erythropoietin response. Treatment with erythropoietin decreases the need for red blood cell transfusion in several disease states. We hypothesized that critically ill children with bronchiolitis and anemia would have a circulating erythropoietin deficiency and that treatment with exogenous erythropoietin would increase reticulocyte count and hematocrit and reduce red blood cell transfusion requirements.DesignRandomized, blinded, placebo-controlled trial.SettingChildren’s hospital.PatientsCritically ill children with bronchiolitis, anemia, and respiratory failure. Anemia was defined as a hematocrit >2 sd below normal for age.InterventionPatients were randomized to one of two groups. In the erythropoietin group, patients received daily intravenous erythropoietin. In the control group, patients received daily intravenous placebo. Both groups were treated with elemental iron.Measurements and Main ResultsBlood for complete blood count, reticulocyte count, and ferritin and erythropoietin concentration was obtained at admission and discharge. Red blood cell transfusions were administered to patients with a persistent oxygen requirement and a hematocrit of <25%. Outcome variables included number of red blood cell transfusions, change in reticulocyte count, ferritin values, and circulating erythropoietin values between groups. Forty-four patients completed the study (mean 3.1 ± 0.6 months), with a baseline hematocrit of 27.6 ± 0.5%, ventilator days of 8.2 ± 0.6, and pediatric intensive care unit length of stay of 9.8 ± 0.6 days. There were no significant baseline demographic differences between the control and erythropoietin groups. Ten of 22 (45%) children in the erythropoietin group required red blood cell transfusion compared with 11 of 22 (50%) in the control group (p= nonsignificant). The increase in reticulocyte count was greater in the erythropoietin group compared with the control group (2.1 ± 0.3% to 4.7 ± 0.7%,p= .003 vs. 2.1 ± 0.3% to 2.7 ± 0.5%,p= nonsignificant).ConclusionsDespite a favorable reticulocyte and circulating erythropoietin response, red blood cell transfusion requirements were not significantly diminished by erythropoietin treatment in children with bronchiolitis and respiratory failure. Erythropoietin cannot be routinely recommended for this patient population.