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A comprehensive search of the medical literature was performed from January 1985 to June 2006. The search, limited to human subjects and English language journals, included MEDLINE®, PubMed, and the Cochrane Database of Systematic Reviews. Clinical practice parameters for obstructive sleep apnea submitted by the American Association of Sleep Medicine can be found at

Obstructive sleep apnea/hypopnea syndrome (OSAHS) is a disease of repetitive episodes of nocturnal upper airway obstruction leading to sleep fragmentation, episodic oxyhemoglobin desaturations, and concomitant daytime hypersomnolence. The hypersomnia associated with OSAHS worsens intellectual capacity, motor coordination, and memory. Studies link this disease to increased motor vehicle accidents and suggest a causal link between OSAHS and cardiovascular disease. Despite increasing awareness of sleep disordered breathing, OSAHS continues to be under-diagnosed. Recognition and diagnosis of this disease is essential as treatment is associated with decreased cardiovascular mortality and improved cognitive function.

A sleep apneic or hypopneic event is caused by pharyngeal narrowing or closure during sleep. In normal subjects, the negative inspiratory pressure of normal breathing tends to close the upper airway. Patency is maintained with activation of pharyngeal dilator muscles. Neuromuscular tone in the upper airway musculature decreases with sleep.1 Excessive adipose tissue, craniofacial abnormalities, and hypertrophic tonsils may result in a smaller upper airway diameter. In patients with a tendency to develop OSAHS, residual pharyngeal muscle activity during sleep may not adequately maintain airway patency. Snoring may cause significant trauma to the upper airway and uvula, leading to edema and further narrowing.2 Sleep fragmentation occurs from arousals that are necessary to reestablish airway patency. These arousals contribute to daytime hypersomnolence.3 The repeated obstructive respiratory events are associated with various cardiovascular effects related to increased sympathetic tone.4

OSAHS is a common disorder. Up to 24% of men and 9% of women between 30 and 60 years of age will have significant sleep disordered breathing defined as more than five events (apneic and/or hypopneic) per hour. Four percent of men and 2% of women in this cohort will have OSAHS defined as a significant number of events with daytime symptoms of sleepiness.5 The prevalence of OSAHS increases with age. Up to 50% of people above age 65 have sleep disordered breathing.6 OSAHS is associated with common diseases. Sixty percent of middle-aged, obese men with a BMI ≥30 kg/m2 will have sleep disordered breathing and 27% will have OSAHS.7 Thirty percent of patients with essential hypertension and 37% of patients with diabetes have sleep apnea. Thirty to thirty-five percent of patients with coronary artery disease (CAD) have significant sleep apnea. OSAHS continues to be under-diagnosed.8 As of 1997, one estimate suggests that 82% of men and 93% of women with moderate-to-severe OSAHS remain undiagnosed.9

Clinical Morbidity

In patients with apnea/hypopnea index (AHI) (the sum of apneas and hypopneas in 1 hour) greater than 11 events ...

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