Impact of acute changes in CPAP flow route in sleep apnea treatment.

CPAP is the gold standard treatment for obstructive sleep apnea (OSA) and was conceived to be applied through a nasal interface. This study was designed to determine the acute effects of changing the nasal CPAP route to oronasal and oral in upper airway patency during sleep in patients with OSA. We hypothesized that the oronasal route may compromise CPAP effectiveness to treat OSA METHODS: Eighteen patients (age: 44±9 years, body mass index: 33.8±4.7 Kg/m(2), apnea-hypopnea: 49.0 ± 39.1 events/hour) slept with a customized oronasal mask with an nasal and oral sealed compartments connected to a multidirectional valve. Sleep was monitored by full polysomnography and induced by low doses of midazolam. Nasal CPAP was titrated up to holding pressure. Flow route was acutely changed to oronasal (n = 18) and oral route (n = 16) during sleep. Retroglossal area was continuously observed by nasoendoscopy.Nasal CPAP (14.8±4.1 cmH2O) was able to stabilize breathing in all patients. In contrast, CPAP delivered by the oronasal and oral route promoted obstructive events in 12 (66.7%) and 14 (87.5%) patients, respectively. Compared to stable breathing during the nasal route, there was a significant and progressive reduction in the distance between the epiglottis and tongue base and the retroglossal area when CPAP was delivered by oronasal and oral route, respectively CONCLUSIONS: CPAP delivered through the oronasal route may compromise CPAP effectiveness to treat OSA.