Sleep apnea ia a very common disorder (up to 10% of men and up to 5% of women) of sleep in which breathing stops while a person is asleep. There are two types of sleep apnea, obstructive and central.
In obstructive sleep apnea, the upper airway becomes obstructed or blocked by the collapse of the soft palate, the tongue and the airway above the voice box (larynx). In people who are predisposed, these tissues sag into the airway as the muscles relax during sleep. As a result, the flow of air is impeded (hypopnea) or stops completely (apnea). As the brain continues to drive breathing movements, the airway collapse becomes worse. Similar in concept is the collapse of a paper soda-straw when one sucks too hard in drinking a thick drink.
Eventually, the brain is forced to arouse itself in order to restart breathing. During the apneas and hypopneas, the blood oxygen level, measured by the oxygen saturation, falls. There may be other events such as irregular heart rhythms or limb movements as well.
Because the obstruction/apneas can be very frequent through the sleep period, sleep becomes fragmented.
Sleep is a very orderly process, normally progressing through early, more superficial stages to the deeper more restful, restorative stages. With each arousal the process must start all over again, which interrupts the flow of sleep and may deprive the patient of the more restorative stages and continuity of sleep.
Symptoms of sleep apnea can be predicted with this process in mind. Snoring is the most common problem and is usually reported by spouses, bedmates, roommates, family and sometimes neighbors. Patients awaken in the morning feeling unrefrreshed, as though they have not slept well or at all. Spouses may observe pauses in the breathing which represent apneas. Patients usually have some degree of of increased or excessive daytime sleepiness especially when inactive (ex. reading, doing papaerwork or driving). Patients often have get up from sleep at night to urinate and may note that they have been sweating in their sleep. There may also be morning headaches. Inability to concentrate ans memory disturbance is common.
Much less frequently, the brain may simply not stimulate an effort to breathe. This is central apnea.Occasionally, this may be from unknown causes or may be the result of neurologic disorders such as stroke or other neuromuscular disorders.
The excessive daytime sleepiness causes a loss of life quality, and the apneas and snoring may cause marital distress due to the impact on the spouse's sleep. There is mounting evidence that sleep apnea is also associated with heart attack, stroke hypertension and trauma (from falling asleep at the wheel or in some other inappropriate situation in which to sleep), resulting in an increased mortality rate.
The diagnosis of sleep apnea is confirmed by doing a sleep study (polysomnogram) which demonstrates the apneas and/or hypoppneas.
Generally, a second sleep study is done in which CPAP (continuous positive ariway pressure) is introduced. CPAP opens the airway much as one blows air into a ballon to inflate the dome of the ballon. Air pressure and airflow is generated by an airpump which is connected to a mask via flexible tubing. The mask fits over the nose (multiple mask types are available for the nose, mouth or the whole face) and is held in place by soft straps around the head.
CPAP is currently the most effective form of treatment. Usually,there is significant improvement in the patient's symptoms. The snoring relieved and the apneas stop. As a result, the person's sleep improves and the daytime sleepiness and fatique clear. The risk of stroke, heart attack and trauma drop to level that would be experienced without the sleep apnea.
Other treatment options include surgery to remove excessive tiissue from the airwayor open the nasal passages. Also, a device can be fitted to pull the lower jaw forward to increase the front-to-back diameter of the airway.