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Myocardial, erythropoietic, and metabolic adaptations to anemia of prematurity
C Lachance1, P Chessex, J C Fouron
1Department of Neonatology, Hôpital Ste-Justine, University of Montreal, Canada.
Insights
Anemia of prematurity in infants does not impair myocardial or metabolic functions. Even with low hemoglobin, oxygenation is maintained without symptoms, suggesting adequate compensatory mechanisms.
Area of Science:
- Neonatal Physiology
- Hematology
- Cardiology
Background:
- Anemia of prematurity is common in premature infants.
- Its effects on myocardial, metabolic, and erythropoietic functions require further investigation.
Purpose of the Study:
- To determine the effects of anemia of prematurity on myocardial, metabolic, and erythropoietic functions in asymptomatic infants.
- To assess these functions before and after packed erythrocyte transfusion.
Main Methods:
- Studied 12 anemic preterm infants (gestational age 28 weeks).
- Assessed cardiac output, heart rate, myocardial function, oxygen consumption, and erythropoietin levels.
- Measurements were taken before and 48 hours after transfusion.
Main Results:
- Transfusion increased hemoglobin from 75 to 150 gm/L.
- Heart rate and cardiac output decreased post-transfusion.
- Erythropoietin levels decreased significantly after transfusion.
- Myocardial function, weight gain, and metabolic demands remained normal.
Conclusions:
- Asymptomatic infants with anemia of prematurity maintain adequate oxygenation.
- Myocardial and metabolic functions are not compromised by this condition.
- Erythropoietic response is suppressed by transfusion, as expected.
Abstract:
We determined the effects of anemia of prematurity on myocardial, metabolic, and erythropoietic functions. Twelve anemic (hemoglobin range, 65 to 78 gm/L) infants without symptoms (gestational age, (mean +/- SD) 28 +/- 2 weeks; birth weight, 1178 +/- 326 gm) were studied at a postconceptional age of 35 +/- 1.6 weeks. All measurements were done before and 36 to 48 hours after a transfusion of packed erythrocytes. Cardiac output, heart rate, and myocardial function were assessed. Oxygen consumption, carbon dioxide production, resting energy expenditure, arterial oxygen pressure for 50% hemoglobin saturation, and the concentrations of erythropoietin and 2,3-diphosphoglycerate were also determined. After transfusion, increased hemoglobin level (75 +/- 4 to 150 +/- 16 gm/L) and decreased oxyhemoglobin affinity (20.8 +/- 1.7 to 23.6 +/- 2.1 gm/L; p < 0.05) caused a decrease in plasma erythropoietin concentration (from 21.1 +/- 6.2 to 5.8 +/- 1.5 mU/ml; p < 0.01). There was a decrease in heart rate (from 155 +/- 10 beats/min to 146 +/- 7 beats/min) and cardiac output (from 281 +/- 73 ml/kg per minute to 199 +/- 62 ml/kg per minute; p < 0.05). Myocardial function indexes, weight gain, and metabolic demands were normal before and after transfusion. These results suggest that oxygenation is adequately maintained in symptom-free infants with anemia of prematurity.