%0 Journal Article %A Marcelo G. Gregorio %A Marcia Jacomelli %A Naury Danzi-Soares %A Fabiola Schorr %A Pedro R. Genta %A Geraldo Lorenzi-Filho %T A new method to determine the site of upper airway obstruction using sleep induced endoscopy in patients with obstructive sleep apnea %D 2011 %J European Respiratory Journal %P p4966 %V 38 %N Suppl 55 %X We evaluated 12 male OSA patients, age= 54±10y; body mass index = 28.8±3.5 kg/m2 and apnea hypopnea-index = 39±18 events/h. The patients were monitored by full polysomnography and sleep was induced by midazolam drip infusion. The patients slept with a nasal mask attached to a flow generator capable of producing positive and negative pressures. After obtaining stable breathing, mask pressure was dialed down for 5 breaths to pre-established levels that induced flow restriction and apnea. Obstruction of the upper airway at the retropalatal (PAL) and retroglossal (GLOS) sites were classified as partial or complete by direct endoscopy visualization.Results: The midazolam dose used was 3.7±2,25 mg and the mask pressure used to obtain flow restriction and apnea was 3.4±2.8 and 0.8±2.9 cmH2O, respectively. The behavior of the upper airways of all patients during flow restriction and apnea is presented below.View this table:Five patients (42%) presented exclusively retropalatal (n=2) or retroglossal (n=3) obstruction during apena, suggesting that the site of obstruction is variable during obstructive events. We conclude that this is a promising method that may help to understand the mechanisms leading to OSA. %U