MYOCARDIAL, ERYTHROPOIETIC, AND METABOLIC ADAPTATIONS TO ANEMIA OF PREMATURITY IN INFANTS WITH BRONCHOPULMONARY DYSPLASIA

Objectives: The effects of anemia of prematurity during bronchopulmona ry dysplasia (BPD) as well as on the metabolic and erythropoietic func tions were determined before and after a transfusion. Fourteen anemic (Hb range: 65-88 gm/L), oxygen dependent (fraction of inspired oxygen less than or equal to 35%), nonventilated, preterm infants with BPD we re studied at a postnatal age of 6 +/- 2 weeks. Study design: Cardiac output, heart rate, mean velocity of circumferential fiber shortening, shortening fraction (SF), and stroke volume were assessed by pulsed a nd continuous wave Doppler echocardiography. Values for resting oxygen consumption, carbon dioxide production, and energy expenditure were o btained by indirect calorimetry. The affinity of oxygenated hemoglobin was determined by a blood oxygen dissociation analyzer. Results: An i ncreased hemoglobin level resulted in a suppression of erythropoietin secretion (p < 0.001), whereas heart rate, cardiac output, stroke volu me, and SF decreased (p < 0.05). Weight gain before and after transfus ion were similar. Plasma lactate levels decreased from 1.6 +/- 0.3 to 1.2 +/- 0.3. Oxygen consumption, carbon dioxide production, and energy expenditure were not affected. Conclusions: Anemia of prematurity and BPD increase heart rate, cardiac output, stroke volume, and SE These hemodynamic compensatory responses are normalized by transfusion.