Effects of mandibular advancement on upper airway dynamics in awake normal subjects: a pilot study with phrenic nerve stimulation.
BACKGROUND
Mandibular advancement (MA) can be an alternative to continuous positive airway pressure (CPAP) in the treatment of obstructive sleep apnea syndrome. This study was designed to describe its effects on upper airway mechanics.


METHODS
Six awake healthy subjects (four men, 31+/-8 years, body mass index (BMI) 25+/-2kg/m2) were studied supine. Phrenic stimulation was used to measure pressure-flow relationships in response to diaphragm contractions without pre-activation of upper airway dilators during progressive MA.


RESULTS
Phrenic stimulation consistently induced flow limitation (initial peak V'-t1, corresponding to the limiting pressure; reduction to a nadir V'-t2; reincrease to a second peak V'-t3). The upper airway resistances were negatively correlated with MA. Their values at 4mm were significantly lower than at baseline. Further MA reduced resistances.


CONCLUSIONS
As with CPAP, MA in normal subjects decreases the propensity of the upper airway to collapse in response to a negative pressure pulse.
Verin
Eric
E
Service de Physiologie, CHU de Rouen, Rouen, France; GRHV EA 3830, Université de Rouen, Rouen, France.
Petelle
Boris
B
Raux
Mathieu
M
Vincent
Gérard
G
Fleury
Bernard
B
Similowski
Thomas
T
D000328:Adult; D015992:Body Mass Index; D004558:Electric Stimulation; D005260:Female; D006801:Humans; D008297:Male; D019186:Mandibular Advancement / Q000379:methods*; D009130:Muscle, Smooth / Q000294:innervation*; D015508:Nasal Obstruction / Q000628:therapy*; D010791:Phrenic Nerve / Q000502:physiology*; D010865:Pilot Projects; D020181:Sleep Apnea, Obstructive / Q000628:therapy*