Obstructive sleep apnea is characterized by recurrent interruptions of breathing during sleep due to temporary obstruction of the airway by lax, excessively bulky, or malformed pharyngeal tissues (soft palate, uvula, and sometimes tonsils), with resultant hypoxemia and chronic lethargy. Sleep in the supine position predisposes apnic episodes. Obstructive sleep apnea (OSA), the most common type of sleep-disordered breathing, affects about 4% of men and 2% of women between the ages of 30 and 60. In addition, it occurs in about 2% of children, largely because of reversible adenotonsillar hyperplasia. It must be distinguished from central sleep apnea, in which apneic episodes during sleep result from impairment of the autonomic respiratory drive. Symptoms are loud snoring, recurrent apneic episodes during sleep followed by gasping inspiration with partial or complete arousal, nocturnal restlessness, and daytime sleepiness. Apneic episodes last 10–120 seconds and may be accompanied by si...