GROWTH REDUCTION DURING DEXAMETHASONE THERAPY IS NOT CAUSED BY INCREASED ENERGY EXPENDITURE. ▴ 1869

In order to investigate the effect of dexamethasone (DEX) therapy on energy expenditure and growth of preterm infants with bronchopulmonary dysplasia, we studied 12 infants (26.2±1.4 wks gestation, 916±190 gm birthweight, mean±sd) enrolled in a multicenter blinded trial of the optimum timing of DEX therapy. The 12 infants were randomly assigned to one of two groups. Group 1 infants (n=6, 25.8±1.5 wks gestation, 932±220 gm birthweight) received a 2 week course of DEX followed by two weeks of placebo. Group 2 infants (n=6, 26.6±1.2 wks gestation, 901±175 gm birthweight) had the treatment order reversed. We measured total energy expenditure (TEE) and total body water (TBW) using the doubly labeled water technique (DLW, ²H and ¹⁸O labeled water) for 7 days during each of the treatment phases. Daily energy intake (EI) and weight were recorded throughout the study. All infants required intermittent mechanical ventilation during some portion of the study and had Respiratory Index Scores (MAP × FiO₂) of 3.4±2.1 at the start of the first DLW period. Results are summarized below (mean ± sd, *p<0.05, DEX vs. placebo). Table

Table 1

Conclusions: TEE or%TBW were unchanged during DEX therapy in both groups. In contrast, rate of weight gain was reduced by >50% during DEX therapy. Lower growth rates during DEX therapy cannot be explained by decreased EI and/or increased TEE.