ERYTHROPOIETIN RESPONSE TO CRITICAL ILLNESS

Objective: To examine the endogenous erythropoietin response in critic ally ill children with acute anemia or acute hypoxemia. Design: A pros pective case study of critically ill acutely anemic, and acutely hypox emic pediatric patients compared with control groups of critically ill nonanemic and nonhypoxemic patients and with a hemoglobin and age-mat ched, chronically anemic patient group. Setting: Multidisciplinary, te rtiary, pediatric intensive care unit (ICU). Patients: Critically in p atients admitted to the pediatric ICU during an 11-month period betwee n February 1992 and March 1993 with acute anemia (n = 21), acute hypox emia (n = 18), or neither anemia nor hypoxemia (n = 10). Outpatients w ith chronic anemia (n = 21) and no acute illness were also studied as a comparison group. Interventions: None. Measurements and Main Results : Ages were equivalent among the groups and averaged 57.4 +/- 47.2 mon ths (range 1 to 144). Acutely hyperemic and critically ill control pat ients had normal hemoglobin levels. Acutely anemic patients had a hemo globin level equivalent to chronically anemic outpatients, but lower ( p < .001) hemoglobin levels than acutely hypoxemic and critically ill control patients. The serum erythropoietin concentrations in the acute ly anemic group were significantly lower than erythropoietin values in the chronically anemic group (39.3 +/- 62.2 vs. 861 +/- 758 mU/mL, p < .001) and similar to erythropoietin concentrations in the critically ill control (13.5 +/- 10.5 mU/mL) and acutely hypoxemic (5.2 +/- 3.3 mU/mL) patient groups. Only ten of 49 critically ill patients had an e rythropoietin concentration above normal, compared with 20 of 21 chron ically anemic patients, whose erythropoietin concentrations were above normal. Conclusions: The erythropoietin response to known physiologic stimuli is blunted in critically ill children. This blunted erythropo ietin response may result in increased transfusion requirements.