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  • • Snoring, or otherwise noisy respiration in sleep.
  • • Periods of respiratory pauses (apneas) witnessed by bed partner or parents.
  • • Fragmented sleep or complaints of insomnia.
  • • Daytime sleepiness and/or fatigue.
  • • Personality changes, intellectual deterioration.
  • • Depression.


Although the sleep-related breathing disorders (SRBD) have been recognized only recently, they are among the most common of all the respiratory disorders. These conditions occur in all age groups but are seen most frequently in middle-aged men.


Estimates from epidemiological studies suggest that 1–5% of the general adult population has obstructive sleep apnea syndrome (OSAS) as defined by evidence of abnormal breathing during sleep combined with symptoms of daytime sleepiness. Other studies have demonstrated that 24% of men and 9% of women aged 30–60 years have an elevated apnea–hypopnea index (AHI) without symptoms.


The impact of mild asymptomatic and often unrecognized obstructive sleep apnea (OSA) on other conditions such as hypertension and cardiovascular disease is an area of extensive research. Population studies indicate a prevalence of sleep-disordered breathing (SDB) in men that is two to three times greater than in women. The prevalence increases throughout the adult years at least until about age 65.

Young T et al: Epidemiology of obstructive sleep apnea. Am J Respir Crit Care Med 2002;165:1217.   [PubMed: 11991871] (State-of-the-art review.)


The obstructive sleep-related breathing disorders can be viewed as manifestations of ever-increasing resistance to airflow in the upper airway. At one end of the continuum is an airway that is always patent in all stages of sleep, positions, and airway inflammation. On the other end is an airway that frequently collapses (obstructive apnea) whenever the patient sleeps. These events can lead to cortical and autonomic nervous system arousals and oxygen desaturations, producing cardiovascular effects. Between these extreme end points a patient may exhibit primary snoring (without evidence of sleep disruption or airway obstruction), sleep fragmentation associated with airflow limitation (and usually snoring) and excessive daytime sleepiness (EDS) but without overt hypopneas or apneas [known as the upper airway resistance syndrome (UARS)], and sleep-related hypopneas associated with arousals and desaturations.


Ventilation occurs when air flows down a gradient of pressure created when the muscles of respiration contract to create negative intrapleural pressure. The muscles dilating the upper airway are activated in a phasic manner allowing the airway to remain open during inspiration. Most patients with sleep apnea appear to have an anatomically narrowed airway, whose patency is maintained during wakefulness due to increased upper airway tone. With sleep onset a normal reduction in airway tone occurs that leaves the upper airway vulnerable to collapse during inspiration. The episodes can be associated with oxygen desaturations and cortical and autonomic arousals. Systemic and pulmonary artery pressures acutely rise and the heart rate increases. These events lead to sleep fragmentation and patients with OSA tend to have increased amounts of light Stage 1 sleep and reduced amounts to ...

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