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Pulmonary function tests and fluid balance in neonates with chronic lung disease during dexamethasone treatment
I M Gladstone1, R A Ehrenkranz, H C Jacobs
1Department of Pediatrics, Yale School of Medicine, New Haven, Connecticut 06477.
Insights
Dexamethasone rapidly improved respiratory function in premature infants with chronic lung disease. This corticosteroid treatment led to significant pulmonary improvements within 48 hours, possibly due to fluid shifts.
Area of Science:
- Neonatal Medicine
- Pediatric Pulmonology
- Pharmacology
Background:
- Premature infants often develop chronic lung disease (CLD) requiring mechanical ventilation.
- Dexamethasone is a corticosteroid used to manage CLD, but its rapid effects are not fully understood.
Purpose of the Study:
- To evaluate the rapid effects of dexamethasone on pulmonary function and fluid balance in ventilator-dependent preterm infants.
Main Methods:
- Serial pulmonary function tests (PFTs) and fluid balance monitoring were conducted in seven preterm infants (24-26 weeks gestation) treated with dexamethasone.
- PFTs included dynamic compliance, total pulmonary resistance, and expiratory time constant.
Main Results:
- Significant improvements in respiratory status were observed within 12 hours of dexamethasone initiation.
- Five infants were extubated within 48 hours.
- Key PFT improvements included a 74% increase in dynamic compliance, 35-38% decrease in total pulmonary resistance, and 49% increase in expiratory time constant (P < .01).
- Increased urine output was noted within 12 hours, suggesting a fluid shift.
Conclusions:
- Dexamethasone produces rapid improvements in CLD in preterm infants.
- These beneficial effects may be mediated by dexamethasone-induced pulmonary fluid shifts.
Abstract:
Pulmonary function tests and fluid balance were measured serially during treatment with dexamethasone in seven ventilator-dependent, 14- to 27-day-old infants. The infants showed no improvement in respiratory status during the prior 5 days. Birth weights ranged from 540 to 900 g, with gestational ages of 24 to 26 weeks. The decision to treat the infants with dexamethasone was made by the clinical team. Pulmonary function tests were performed prior to the first dose and then every 12 hours until extubation. Significant differences were first seen after only 12 hours of treatment. Five infants were extubated within 48 hours of starting therapy. Before extubation at 48 hours, changes were found in dynamic compliance (74% increase), total pulmonary resistance by midvolume and regression methods (38% and 35% decreases, respectively), and expiratory time constant (49% increase), with P less than .01 in all cases. An increase in urine output was also observed in the first 12 hours. Improvements in chronic lung disease produced by dexamethasone are rapid and may result from dexamethasone-induced pulmonary fluid shifts.