title: Inspiratory flow dynamics during phrenic nerve stimulation in awake normals during nasal breathing.
abstract: The loss of upper airway (UA) dilators preactivation before inspiratory muscle contraction is an important determinant of the pathophysiology of obstructive sleep apnea. We hypothetized that phrenic nerve stimulation could provide a practical way to explore the effects of the dissociation between UA dilators and inspiratory muscles, and possibly to determine UA critical closing pressure during wakefulness. The pattern of inspiratory airflow was therefore studied in normal awake subjects during diaphragm twitches induced by either electrical phrenic stimulation (ES) or cervical magnetic stimulation (CMS) (n = 9) and with and without a nasal stent during ES (n = 7). End-expiratory stimulations applied during exclusive nasal breathing induced 200 to 300 ms twitch inspiratory flow. The average maximal twitch flow of flow-limited twitches was higher during CMS than ES (1.18 +/- 0.29 L.
authors.affiliation: Unité de Recherche, Centre de pneumologie de l'Hôpital Laval, Université Laval, Québec, Canada. Frederic.Series@med.ulaval.ca
authors.forename: F
authors.initials: F
authors.lastname: Sériès
authors.forename: A
authors.initials: A
authors.lastname: Demoule
authors.forename: I
authors.initials: I
authors.lastname: Marc
authors.forename: C
authors.initials: C
authors.lastname: Sanfaçon
authors.forename: J P
authors.initials: JP
authors.lastname: Derenne
authors.forename: T
authors.initials: T
authors.lastname: Similowski
mesh_terms: D000328:Adult; D000403:Airway Resistance / Q000502:physiology; D004558:Electric Stimulation; D004576:Electromyography; D005260:Female; D006801:Humans; D007320:Inspiratory Capacity / Q000502:physiology*; D008297:Male; D015508:Nasal Obstruction / Q000503:physiopathology; D010791:Phrenic Nerve / Q000503:physiopathology*; D012123:Pulmonary Ventilation / Q000502:physiology; D015656:Respiratory Mechanics / Q000502:physiology*; D012132:Respiratory Muscles / Q000294:innervation; D012891:Sleep Apnea Syndromes / Q000503:physiopathology; D015607:Stents