Sequential Energy Balance (EB) Studies in Preterm Infants. 1561

Background: Sequential measurements of EB are not readily available.Subjects: 18 healthy infants (birthweight = 1.35 ± 0.21 kg, gestation = 210 ± 10 days; mean ± SD).Methods: Energy expenditure (EE) was measured using indirect calorimetry. Energy Intake (EI) and absorption (EA) were measured using 48-hour nutrient balances on three occasions. A standard low birthweight formula was used during the study. Data was analysed using ANOVA, p < 0.05 was considered significant. Results: 54 balances and 30 EE determinations were performed at post-conceptual ages of 233±9, 243±7 & 337±4 d and weights of 1.77±0.26, 2.20±0.31 and 5.13±0.93 kg respectively. No consistent differences were noted between balances 1 and 2. However, EI, EA, EE, and energy, protein, and fat stored were different during 1 and 2 compared to 3. Calculated energy, protein and fat stored were greater than the reference fetus or infant at the same age. Conclusion: The nature and quantity of nutrient utilisation/storage changes with age. Differences between the study and reference group may, in part, reflect methodological limitations. Differences may also reflect increased storage associated with 'catch-up' growth in these nutritionally-deprived infants. Table