title: Laryngeal muscle activity during nasal high-frequency oscillatory ventilation in nonsedated newborn lambs.
abstract: BACKGROUND
  We have previously shown that nasal pressure support ventilation (nPSV) can lead to an active inspiratory laryngeal narrowing in lambs. This, in turn, can limit lung ventilation and divert air into the digestive system, with potentially deleterious consequences. On the other hand, nasal high-frequency oscillatory ventilation (nHFOV) is particularly attractive in newborns, especially since, unlike nPSV, it does not require synchronization with the patient's inspiratory efforts.
  
  
  OBJECTIVE
  The main aim of the present study was to test the hypothesis that glottal constrictor muscle activity (EMG) does not develop during nHFOV. A secondary objective was to study laryngeal EMG during nHFOV-induced central apneas.
  
  
  METHODS
  Polysomnographic recordings were performed in 7 nonsedated lambs which were ventilated with increasing levels of nPSV and nHFOV at both 4 and 8 Hz, in random order. States of alertness, diaphragm and glottal muscle EMG, SpO2, and respiratory movements were continuously recorded.
  
  
  RESULTS
  While phasic inspiratory glottal constrictor EMG appeared with increasing nPSV levels in 6 out of 7 lambs, it was never observed with nHFOV. In addition, nHFOV at 4 Hz dramatically inhibited central respiratory drive in 4/7 lambs, with 64-100% of recording time spent in central apnea in 3 lambs. No glottal constrictor EMG was observed during these central apneas.
  
  
  CONCLUSIONS
  nHFOV does not induce glottal constrictor muscle EMG in nonsedated newborn lambs, in contrast to nPSV. This may be an additional advantage of nHFOV relative to nPSV.
authors: Neonatal Respiratory Research Unit, Departments of Pediatrics and Physiology, Université de Sherbrooke, Sherbrooke, Que., Canada.
authors: Mohamed Amine
authors: MA
authors: Hadj-Ahmed
authors: Nathalie
authors: N
authors: Samson
authors: Charlène
authors: C
authors: Nadeau
authors: Nadia
authors: N
authors: Boudaa
authors: Jean-Paul
authors: JP
authors: Praud
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D005931:Glottis / Q000503:physiopathology*; D006612:High-Frequency Ventilation; D007821:Laryngeal Muscles / Q000503:physiopathology*; D017286:Polysomnography; D034561:Sheep, Domestic; D020182:Sleep Apnea, Central / Q000175:diagnosis*