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Dexamethasone therapy for bronchopulmonary dysplasia: improved respiratory mechanics without adrenal suppression
K L Brundage1, K G Mohsini, A B Froese
1Department of Physiology, Queen's University, Kingston, Ontario, Canada.
Insights
Dexamethasone (Dex) improved respiratory mechanics in infants with bronchopulmonary dysplasia (BPD) by increasing compliance and decreasing resistance, without causing adrenal suppression. This treatment facilitated extubation in these vulnerable infants.
Area of Science:
- Neonatology
- Pediatric Pulmonology
- Pharmacology
Background:
- Bronchopulmonary dysplasia (BPD) is a chronic lung disease in premature infants.
- Respiratory system dysfunction is a hallmark of BPD, necessitating mechanical ventilation.
- Dexamethasone (Dex) is a corticosteroid with anti-inflammatory properties.
Purpose of the Study:
- To investigate the effects of dexamethasone (Dex) on respiratory system mechanics in infants with BPD.
- To determine if the dosage of Dex used causes adrenal suppression.
- To assess the relationship between respiratory mechanics and extubation success.
Main Methods:
- Seven ventilator-dependent premature infants with BPD received intravenous Dex (0.5 mg/kg/day) for up to 7 days.
- Respiratory system resistance (Rrs) and compliance (Crs) were measured daily using the passive expiratory flow-volume technique.
- Adrenocorticotrophic hormone (ACTH) stimulation tests were performed at baseline and post-therapy to assess adrenal function.
Main Results:
- Dex therapy significantly increased Crs by 77% and decreased Rrs by 33%.
- Ventilator settings (rate, mean airway pressure, FIO2) were significantly reduced.
- No adrenal suppression was observed; systolic blood pressure increased, and no sepsis occurred.
Conclusions:
- Dexamethasone (Dex) effectively improves respiratory system mechanics in infants with bronchopulmonary dysplasia (BPD).
- The studied Dex dosage does not appear to induce adrenal suppression in this population.
- Improved respiratory mechanics correlate with successful extubation in infants with BPD.
Abstract:
The purpose of the present study was to examine the pattern of changes in respiratory system mechanics induced by dexamethasone (Dex) in infants with bronchopulmonary dysplasia (BPD) and to determine whether dosages that produce these changes induce adrenal suppression. We examined mechanics in seven ventilator-dependent premature infants (age, 33 +/- 4.8 days) with BPD, before and daily during Dex therapy. Dex (0.5 mg/kg/day) was given intravenously for 7 days unless complications necessitated early termination. Respiratory system resistance (Rrs) and compliance (Crs) were measured by the passive expiratory flow-volume technique during the course of dexamethasone therapy or until extubation. Adrenocorticotrophic hormone (ACTH) stimulation tests were done at baseline and following Dex therapy to evaluate adrenal function. Dex therapy caused a 77 +/- 18% increase in Crs (from 0.97 +/- 0.09 SEM mL/cmH2O to 1.6 +/- 0.16 mL/cmH2O; P less than 0.025) and a 33 +/- 5% decrease in Rrs (from 0.20 +/- 0.02 cmH2O/mL/s to 0.14 +/- 0.01 cmH2O/mL/s; P less than 0.01). Concurrently, ventilator rate, mean airway pressure, and FIO2 all decreased significantly (P less than 0.025). Extubation occurred later in infants with the lowest Crs and highest Rrs at baseline. At extubation, all Crs values were greater than 1.33 mL/cmH2O and Rrs values were less than 0.15 cmH2O/mL/s. Systolic blood pressure increased from 61 +/- 6.3 mmHg to 84 +/- 17 mmHg, 72-96 h after the start of Dex (P less than 0.025). There were no episodes of culture-positive sepsis. Neither basal nor ACTH-stimulated levels of cortisol were suppressed as a result of Dex therapy (P greater than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)