Abstract 148

Background.-Corticosteroid-treated premature infants with bronchopulmonary dysplasia (BPD) may precociously exhibit an appreciable rise in the diuresis and a decrease in weight gain, associated with pulmonary function improvement.

Aim. To determine whether diuresis is primarily the result of steroid endogenous AVP inibition.

Subjects and methods.-Plasma AVP(Vasopressin-Rapid RIA Method, Buhlman Laboratories AG, Basel, Switzerland) and osmolality, serum sodium and potassium concentrations, 12-hour urine output and osmolality were measured before and three days after the start of dexamethasone (0.5 mg/kg/day IM or IV) in 8 prematures with BPD, aged 1-2 months.

Results.-All infants required supplemental oxygen (FiO2>4 0%) to maintain a O2 saturation of >92%, and 7 also required mechanical ventilation during the study period. None of the infants were receiving any diuretics or cardiac drugs during the study. Means(±SD) values were as follows: Table

Table 1
Full size table

Conclusions.-These data indicate that some infants with BPD have elevated AVP levels, that are not functionally modified after 3-day dexamethasone administration. The significant increase in osmolar diuresis has no correlation or temporal relationship with hypervasopressinemia.