RESUMO
OBJECTIVE: To describe the effect of systemic corticosteroids administered to treat evolving bronchopulmonary dysplasia on oxygen diffusion and ventilation efficiency. STUDY DESIGN: This was a retrospective cohort study of ventilated infants who received a 9-day course of dexamethasone in a tertiary neonatal unit. We calculated the transcutaneous oxygen saturation-to-fraction of inspired oxygen (FiO2) ratio (SFR), the ventilation perfusion ratio (VA/Q), and the ventilation efficiency index (VEI) before, during, and after the course of corticosteroids. The response to corticosteroids was calculated as the difference between the FiO2 percentage before starting steroids and the lowest FiO2 value during the course of steroid treatment. RESULTS: Seventy infants (38 males) with a median gestational age (GA) of 25.0 weeks (IQR, 24.3-26.0 weeks) and a median birth weight of 0.70 kg (IQR, 0.63-0.82 kg) were studied at a median postnatal age of 39 days (IQR, 29-48 days). The median SFR before treatment was 1.42 (IQR, 1.19-1.72), and the highest SFR was 2.35 (IQR, 1.87-2.83) after 9 days of treatment. The median VA/Q before treatment was 0.14 (IQR, 0.11-0.18) and was significantly higher at 72 hours after the start of treatment (0.22; IQR, 0.15-0.29; P < .001). The median VEI was 0.06 (IQR, 0.04-0.08) before treatment and was highest, 0.10 (IQR, 0.07-0.13) at 48 hours after starting treatment. The median rate of response to corticosteroids was 28% (IQR, 20%-37%). GA was significantly related to the response to corticosteroids (ρ = 0.283; P = .019). CONCLUSIONS: Oxygen diffusion continues to improve throughout the entire duration of a 9-day course of systemically administered corticosteroids in ventilated extremely preterm infants. More immature infants are less responsive to corticosteroids.
Assuntos
Displasia Broncopulmonar/terapia , Ritmo Circadiano/fisiologia , Dexametasona/administração & dosagem , Lactente Extremamente Prematuro , Cuidado Pós-Natal/métodos , Respiração Artificial/métodos , Volume de Ventilação Pulmonar/fisiologia , Displasia Broncopulmonar/diagnóstico , Displasia Broncopulmonar/fisiopatologia , Feminino , Seguimentos , Idade Gestacional , Glucocorticoides/administração & dosagem , Humanos , Lactente , Recém-Nascido , Unidades de Terapia Intensiva Neonatal , Masculino , Consumo de Oxigênio , Estudos Retrospectivos , Resultado do TratamentoRESUMO
The ventilatory response of infants of mothers who smoke and misuse substances and controls to carbon dioxide was assessed at 6-12 weeks and the perinatal period. Infants of mothers who smoke and misuse substances had a dampened response at the peak age of sudden infant death syndrome, greater than in the perinatal period.