Background: The high efficacy of continuous positive airway pressure (CPAP) in treating obstructive sleep apnea (OSA) is limited by poor compliance often related to pressure intolerance. Mandibular advancement devices (MADs) are proven alternative therapy although not universally effective. A combination of nasal CPAP and MAD may provide another option for CPAP-intolerant patients with incomplete response to MAD.
Methods: Ten patients with residual apnea/hypopnea events on MAD who were intolerant to CPAP were recruited prospectively from the sleep clinic. After a washout period of 1 week off MAD, subjects were asked to use an auto-CPAP unit along with their prescribed MAD for three consecutive nights. Oxygen desaturations were obtained from overnight oximetry. Efficacy of the combination therapy was evaluated by the Epworth Sleepiness Scale and Smartcard data recordings.
Results: The combination of MAD and nasal CPAP was well tolerated by all participants. Compared to CPAP alone, the optimal CPAP pressure required to eliminate all obstructive events on the combination therapy was reduced from 9.4 ± 2.3 to 7.3 ± 1.4 cm H₂O (p = 0.001). The residual apnea hypopnea index on the MAD decreased from 11.2 ± 3.9 to 3.4 ± 1.5 on the combination therapy (p < 0.001). The number of oxygen desaturations was also less with the combination therapy than with MAD (p < 0.001). Both the MAD and the combination therapy were effective in reducing daytime sleepiness from 12.7 ± 2.1 at baseline to 9.7 ± 3.1 (p = 0.04) and 7.5 ± 4.1 (p = 0.007), respectively.
Conclusions: Combination therapy of MAD and nasal CPAP is effective in normalizing respiratory disturbances of sleep apnea in selected OSA patients who are intolerant to CPAP.