Sleep Center

Sleep Apnea Information
Sleep apnea afflicts more than 12 million people in the United States. It takes its name from the Greek word apnea, which means "without breath." People with sleep apnea stop breathing repeatedly during their sleep, often for a minute or longer, and as many as hundreds of times during a single night. Sleep apnea can be caused by complete obstruction of the airway (obstructive apnea) or partial obstruction (obstructive hypopnea; hypopnea is slow, shallow breathing), both of which can disrupt sleep. There are three types of sleep apnea — obstructive, central, and mixed. Of these, obstructive sleep apnea (OSA) is the most common. OSA occurs in approximately 2% of women and 4% of men over the age of 35.

But there’s good news: Most sleep orders can be treated – but only if recognized and properly diagnosed. The Sleep Center at Osler is a specialized facility providing accurate diagnosis and treatment of sleep-related problems.

Physiology and Causes

The Sleep Center features two private rooms for diagnostic sleep studies. Each is individually climate controlled, allowing studies to be performed both night and day, so patients receive diagnosis and treatment during their normal sleeping hours. This is critical for shift workers whose regular sleep cycle is during the day and for patients who suffer from disorders such as narcolepsy (which causes sleep at inappropriate times). The center’s state-of-the-art laboratory is equipped to monitor brain waves, breathing, heart activity, muscle activity and other functions in order to uncover the source of sleep problems. The results of these tests are reviewed by the Sleep Center staff, who then develop a plan for treatment. Treatments include lifestyle changes, breathing aid devices and medications.

The cause of OSA is unclear. The site of obstruction in most patients is the soft palate, extending to the region at the base of the tongue. The body has no rigid structure, such as cartilage or bone, in this area to keep the airway open. During the day, muscles in the region keep the passage open. As a person with OSA falls asleep, these muscles relax to a point where the airway collapses and becomes obstructed. When the airway closes, breathing stops, and the sleeper awakens to open the airway. The arousal from sleep usually lasts only a few seconds, but brief arousals disrupt continuous sleep and prevent the person from reaching the deep stage of rapid eye movement (REM) sleep, which the body needs to rest and replenish its strength. Once normal breathing is restored, the person falls back to sleep, only to repeat the cycle throughout the night.

Typically, the frequency of waking episodes is somewhere between 10 and 60. A person with severe OSA may have more than 100 waking episodes in a single night.

Risk Factors

The primary risk factor for OSA is excessive weight gain. The accumulation of fat on the sides of the upper airway causes it to become narrow and predisposed to closure when the muscles relax. Age is another prominent risk factor. Loss of muscle mass is a common consequence of the aging process. If muscle mass decreases in the airway, it may be replaced with fat, leaving the airway narrow and soft. Men have a greater risk for OSA. Male hormones can cause structural changes in the upper airway. Other predisposing factors associated with OSA include the following:

• Anatomic abnormalities, such as a receding chin
• Enlarged tonsils and adenoids (the main causes of OSA in children)
• Family history of OSA, although no genetic inheritance pattern has been proven
• Use of alcohol and sedative drugs, which relax the musculature in the upper airway
• Smoking, which can cause inflammation, swelling, and narrowing of the upper airway
• Hypothyroidism, acromegaly, amyloidosis, vocal cord paralysis, post-polio syndrome, neuromuscular disorders, Marfan's syndrome, and Down's syndrome
• Nasal congestion

Signs and Symptoms

The signs and symptoms of OSA result from disruption of the normal sleep architecture. The frequent arousals and the inability to achieve or maintain the deep stages of sleep can lead to excessive daytime sleepiness, nonrestorative sleep, automobile accidents, personality changes, decreased memory, impotence, and depression.

Patients rarely complain about frequent awakenings due to obstruction, but it does occur. Excessive daytime sleepiness may be mild or severe, depending on the severity of the obstruction. Some patients suffering from OSA fall asleep in a non-stimulating environment, such as while reading in a quiet room. Others may fall asleep in a stimulating environment, such as during business meetings, while eating, and even while having sex. Patients with OSA often complain of waking up feeling like they had not slept at all. They often feel worse after taking a nap than before napping.

So-called "drowsy driver syndrome", which some law enforcement authorities believe to be responsible for many automobile accidents, may result from OSA. Drivers may fall asleep at the wheel or suffer from a lack of alertness because of sleep deprivation. Decreased alertness places the person at risk in a variety of potentially hazardous situations. It is recommended that persons with excessive daytime sleepiness do not drive or operate dangerous equipment until their condition is effectively treated. Other symptoms of OSA, such as morning headaches and frequent urination during the night, may also be caused by apneic events.

Physical signs that suggest OSA include loud snoring, witnessed apneic episodes, and obesity. Patients with OSA often maintain that their only problem is that others complain about their snoring. A large number of snorers may have OSA. Many times, a sleep partner will witness an apneic event.

Hypertension is prevalent in patients with OSA, although the exact relationship is unclear. It has been shown, however, that treating OSA can modestly lower blood pressure.

Complications The most obvious complication from OSA is diminished quality of life brought on by chronic sleep deprivation and the symptoms described above. Coronary artery disease, cerebral vascular events (strokes), and congestive heart failure are being evaluated to determine their connection to OSA. A link between OSA and coronary artery disease and stroke has been demonstrated, although it is still uncertain whether OSA leads to an increased risk of stroke and coronary artery disease or if OSA and cardiovascular problems are caused by a common problem, such as obesity. Obstructive sleep apnea aggravates congestive heart failure by placing stress on the heart during sleep. There is a high prevalence of OSA in patients with congestive heart failure. Congestive heart failure patients also may have central sleep apnea, a condition in which the brain signals the patient to stop breathing for short periods of time.