Mechanisms of the effectiveness of continuous positive airway pressure in obstructive sleep apnea.

Nasal continuous positive airway pressure (NCPAP) is considered the most effective treatment of obstructive sleep apnea. Its beneficial effects are related to the normalization of breathing during sleep and to the prevention of nocturnal desaturations. NCPAP interacts with the pathophysiologic mechanisms of sleep apnea onset and with the consequences of these apneas. Upper airway patency is maintained with NCPAP by a pneumatic splinting effect while changes in lung volume and pre-apnea SaO2 level may be implicated in the improvement of apnea-related desaturations. An improvement in central chemosensitivity could account for the improvement in diurnal oxygenation observed with long term NCPAP therapy.