CPAP THERAPY VIA ORONASAL MASK FOR OBSTRUCTIVE SLEEP-APNEA

Study objective: To determine the effectiveness of oronasal masks for positive pressure therapy in alleviating obstructive sleep apnea (OSA). Methods and procedures: Polysomnographic records of all 245 patients with OSA who underwent therapeutic trials of either continuous positive airway pressure (CPAP) or bilevel positive airway pressure between January 1991 and December 1992 were reviewed. Thirty patients who had been prescribed positive pressure therapy employing an oronasal mask were identified. Two patients known to be successfully treated with CPAP via oronasal mask underwent repeat polysomnography. The initial portion of the study was a diagnostic evaluation during which the patients were untreated. During the second portion of the study, both patients used CPAP via an oronasal mask while wearing a mouthpiece designed to maintain oral patency. Results: The 30 patients with OSA who were identified in this study had significant amelioration of OSA while receiving positive pressure therapy via oronasal mask compared with the baseline, diagnostic polysomnogram (apnea index: 55.3+/-36.9-->1.6+/-3.7, p<0.001; hypopnea index: 21.2+/-20-->2.7+/-4.9, p<0.001; nadir of SaO(2): 72.5+/-13.9-->87.1+/-4.3, p<0.001, mean+/-SD). Improvement of OSA did not depend on maintenance of a closed mouth, as evidenced by elimination of sleep-disordered breathing in the two patients receiving positive pressure via oronasal mask while wearing a mouthpiece to keep the mouth open. Conclusion: Oronasal masks are a viable alternative interface for alleviating OSA with positive pressure therapy in those patients who are unwilling or unable to tolerate conventional nasal interfaces. Although there were no adverse consequences associated with the use of oronasal masks in our patients, appropriate safety precautions should be taken to minimize the possibility of aspiration of gastric contents and avoid untoward sequelae due to positive pressure device failure.