title: High-frequency nasal ventilation for 21 d maintains gas exchange with lower respiratory pressures and promotes alveolarization in preterm lambs.
abstract: 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 (O2) 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 (FiO2), 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/FiO2 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.
  
  
  CONCLUSIONS
  Long-term HFNV provides acceptable gas exchange at lower inspired O2 levels and respiratory pressures compared to intubation and IMV.
authors.affiliation: Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, Utah.
authors.forename: Donald M
authors.initials: DM
authors.lastname: Null
authors.affiliation: Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, Utah.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Alvord
authors.affiliation: Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, Utah.
authors.forename: Wendy
authors.initials: W
authors.lastname: Leavitt
authors.affiliation: Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, Utah.
authors.forename: Albert
authors.initials: A
authors.lastname: Wint
authors.affiliation: Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, Utah.
authors.forename: Mar Janna
authors.initials: MJ
authors.lastname: Dahl
authors.affiliation: Division of Epidemiology, University of Utah, Salt Lake City, Utah.
authors.forename: Angela P
authors.initials: AP
authors.lastname: Presson
authors.affiliation: Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, Utah.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Lane
authors.affiliation: Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, Utah.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: DiGeronimo
authors.affiliation: Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, Utah.
authors.forename: Bradley A
authors.initials: BA
authors.lastname: Yoder
authors.affiliation: 1] Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, Utah [2] Department of Internal Medicine, University of Utah, Salt Lake City, Utah; [3] Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah.
authors.forename: Kurt H
authors.initials: KH
authors.lastname: Albertine
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D006612:High-Frequency Ventilation / Q000379:methods*; D009666:Nose; D011650:Pulmonary Alveoli / Q000166:cytology*; D012119:Respiration; D012756:Sheep