Apnea is defined as a cessation of oronasal airflow of at least 10 seconds in duration. When it occurs 30 or more times during a 7-hour period of nocturnal sleep, it is called obstructive sleep apnea (OSA) and requires immediate intervention to prevent it from becoming life-threatening.
In the most common form of the condition - obstructive apnea (also called upper airway apnea) - air stops flowing through the nose and mouth, but throat and abdominal breathing efforts are uninterrupted. The snoring that results is produced when the upper rear of the mouth (the soft palate and the cone-shaped tissue - the uvula - that descends from it) relaxes and vibrates as air passes in and out. This sets up an air current between the palate and the base of the tongue, resulting in snoring. Typically, the individual will wake up, emit a vigorous snort or grunt while gasping for air, then immediately fall back to sleep, only to repeat the cycle. In another form of the disorder, central apnea, both oral breathing and throat and abdominal breathing efforts are simultaneously interrupted. In a third type of apnea, mixed apnea, a brief period of central apnea is followed by a longer period of obstructive apnea. Sleep apnea can be recognized by a number of symptoms. Loud and intermittent snoring is one warning signal. The person who has sleep apnea may experience a choking sensation, early-morning headaches, or extreme daytime sleepiness as well. His bed partner or roommate might comment on his excessive body movements or his snorting or gasping for breath during sleeping. If the condition is suspected, it should be reported to a physician, who may recommend evaluation by a specialist in sleep disorders. Since sleeping pills may be harmful for people with sleep apnea, they should not be taken if the condition is suspected.
Sleep apnea is believed to affect at least 1 out of every 200 Americans - 70 to 90 percent are men, mostly middle-aged and usually overweight. But the condition can afflict both men or women at any age.
People with this disorder actually may stop breathing while asleep - even hundreds of times - without being aware of the problem. During an apnea attack, the snorer may seem to gasp for breath, and the blood may become abnormally low. In severe cases, a sleep apnea victim may actually spend more time not breathing than breathing and may be at risk for death.
Polysomnography, a technique used to diagnose obstructive sleep apnea, records the number and duration of apnetic episodes, determines the stage of sleep and oxygen saturation and observes when the patient awakens.
A physician can diagnose sleep apnea and suggest treatment based on the patient's complaints of daytime sleepiness, insomnia, awareness of obstructed breathing during sleep, snoring, and headache or dry mouth on waking. The physician examines the bones of the face and jaw and throat structures such as palates, uvula and tonsils while the patient is in various positions, to see the sizes of spaces through which inhaled air can pass. X-rays may help envision how these structures lie. Definitive diagnosis of sleep apnea depends upon the results of a battery of tests, called polysomnography, which are run in a sleep lab. A diagnosis of sleep apnea is made when polysomnography indicates more than five apnetic episodes, of 10 seconds or longer duration per hour of sleep, plus an irregular heartbeat, frequent arousal during sleep, or dips in arterial oxygen saturation. For mild obstructive sleep apnea, treatment often consists of avoiding sleep on one's back. Other people have a significant problem when the nose is congested, so decongestant therapy may be helpful for them. A more drastic treatment if the patient is overweight, is weight reduction. It is also recommended to avoid central nervous system depressants, such as alcoholic beverages, or hypnotic or sedative drugs. Most serious sleep apnea cases can be relieved by a treatment called nasal continuous positive airway pressure, or CPAP. CPAP uses a small mask held onto the nose by straps, and has pouches that insert into the nostrils. The mask is connected to a motor that regulates the amount and pressure of air sent into the nose, exerting pressure to keep the nasal passages open. The pressure is determined by polysomnography. CPAP works by holding open the nose and the back of the throat. CPAP usually brings immediate relief. Snoring stops. A smooth breathing pattern is restored. Blood oxygen levels stabilize. During the first week of CPAP therapy, the sleep pattern may still be grossly abnormal, but with peaceful stretches of sleep gradually growing, as if the body is trying to catch up. Sleep eventually settles down to a more normal pattern, often for the first time in years. Unfortunately, many CPAP users never continue therapy beyond the first night, let alone for the first week, because they find sleeping with a mask on the face uncomfortable. Other forms of surgery might provide relief for the 10 percent of patients with serious sleep apnea for whom CPAP does not work. In the nearly unpronounceable but helpful uvulopalatopharyngoplasty (UPPP), the back part of the soft palate and tissue at the back of the throat are removed, opening up more airspace.