[Effects of nasal continuous positive airway pressure on patients with obstructive sleep apnea syndrome]

To evaluate the efficacy of nasal continuous positive airway pressure (CPAP) on patients with obstructive sleep apnea syndrome, 20 patients with moderate to severe obstructive sleep apnea syndrome (respiratory disturbance index greater than or equal to 20) were studied. The patients were evaluated using the Grass polysomnograph model 78 during an overnight sleep one to two weeks apart with and without a nasal CPAP produced by 10 to 15 cm of water. The results showed that nasal CPAP significantly reduced the respiratory disturbance index (RDI) (p less than 0.001) and the desaturation index (p less than 0.001), and significantly raised the lowest oxygen saturation level. Nasal CPAP not only reduced RDI, but also improved the respiratory patterns during obstructive apnea events by shifting the obstructive apnea events to hypopnea events. Nasal CPAP also significantly decreased the relative time spent in stage 1 NREM sleep (p less than 0.001), and increased the relative time spent in stages 3+4 NREM and REM sleep (p less than 0.05). Most of the patients also felt better the morning after using nasal CPAP. Nasal CPAP significantly reduced the frequency and duration of apnea and the degree of nocturnal oxygen desaturation, and improved the respiratory patterns during obstructive apnea events, as well as the sleep architecture in obstructive sleep apnea patients. We conclude that nasal CPAP is effective in moderate to severe obstructive sleep apnea syndrome patients.