High-frequency nasal ventilation for 21 d maintains gas exchange with lower respiratory pressures and promotes alveolarization in preterm lambs

Background: Short-term high-frequency nasal ventilation (HFNV) of preterm neonates provides acceptable gas exchange compared to endotracheal intubation and intermittent mandatory ventilation (IMV). Whether long-term HFNV will provide acceptable gas exchange is unknown. We hypothesized that HFNV for up to 21 d would lead to acceptable gas exchange at lower inspired oxygen (O ₂) levels and airway pressures compared to intubation and IMV. Methods: Preterm lambs were exposed to antenatal steroids and treated with perinatal surfactant and postnatal caffeine. Lambs were intubated and resuscitated by IMV. At ∼3 h of age, half of the lambs were switched to noninvasive HFNV. Support was for 3 or 21 d. By design, Pao₂ and Paco₂ were not different between groups. Results: At 3 d (n = 5) and 21 d (n = 4) of HFNV, fractional inspired O₂ (F_iO ₂), peak inspiratory pressure (PIP), mean airway, intratracheal, and positive end-expiratory pressures, oxygenation index, and alveolar-arterial gradient were significantly lower than matched periods of intubation and IMV. Pao₂/F_iO₂ ratio was significantly higher at 3 and 21 d of HFNV compared to matched intubation and IMV. HFNV led to better alveolarization at 3 and 21 d. Conclusion: Long-term HFNV provides acceptable gas exchange at lower inspired O₂ levels and respiratory pressures compared to intubation and IMV.