Sleep apnea

Definition

Sleep apnea is a condition in which breathing stops for more than ten seconds during sleep. Sleep apnea is a major, though often unrecognized, cause of daytime sleepiness. It can have serious negative effects on a person's quality of life, and is thought to be considerably underdiagnosed in the United States.

Description

A sleeping person normally breathes continuously and without interruption throughout the night. A person with sleep apnea, however, has frequent episodes (up to 400-500 per night) in which he or she stops breathing. This interruption of breathing is called "apnea." Breathing usually stops for about 30 seconds; then the person usually startles awake with a loud snort and begins to breathe again, gradually falling back to sleep.

There are two forms of sleep apnea. In obstructive sleep apnea (OSA), breathing stops because tissue in the throat closes off the airway. In central sleep apnea, (CSA), the brain centers responsible for breathing fail to send messages to the breathing muscles. OSA is much more common than CSA. It is thought that about 1–10% of adults are affected by OSA; only about one tenth of that number have CSA. OSA can affect people of any age and of either sex, but it is most common in middle-aged, somewhat overweight men, especially those who use alcohol.

Causes & symptoms

Obstructive sleep apnea

Obstructive sleep apnea occurs when part of the airway is closed off (usually at the back of the throat) while a person is trying to inhale during sleep. People whose airways are slightly narrower than average are more likely to be affected by OSA. Obesity, especially obesity in the neck, can increase the risk of developing OSA, because the fat tissue tends to narrow the airway. In some people, the airway is blocked by enlarged tonsils, an enlarged tongue, jaw deformities, or growths in the neck that compress the airway. Blocked nasal passages may also play a part in some people's apnea.

When a person begins to inhale, expansion of the lungs lowers the air pressure inside the airway. If the muscles that keep the airway open are not working hard enough, the airway narrows and may collapse, shutting off the supply of air to the lungs. OSA occurs during sleep because the neck muscles that keep the airway

open are not as active then. Congestion in the nose can make collapse more likely, since the extra effort needed to inhale will lower the pressure in the airway even more. Drinking alcohol or taking tranquilizers in the evening worsens this situation, because these substances cause the neck muscles to relax. These drugs also lower the "respiratory drive" in the nervous system, reducing breathing rate and strength.

People with OSA almost always snore heavily, because the same narrowing of the airway that causes snoring can also cause OSA. Snoring may actually help cause OSA as well, because the vibration of the throat tissues can cause them to swell. However, most people who snore do not go on to develop OSA.

Other risk factors for developing OSA include male sex; pregnancy ; a family history of the disorder; and smoking . With regard to gender, it has been found that male sex hormones sometimes cause changes in the size or structure of the upper airway. The weight gain that accompanies pregnancy can affect a woman's breathing patterns during sleep, particularly during the third trimester. With regard to family history, OSA is known to run in families even though no gene or genes associated with the disorder have been identified as of 2002. Smoking increases the risk of developing OSA because it causes inflammation, swelling, and narrowing of the upper airway.

Some patients being treated for head and neck cancer develop OSA as a result of physical changes in the muscles and other tissues of the neck and throat. Doctors recommend prompt treatment of the OSA to improve the patient's quality of life.

Central sleep apnea

In central sleep apnea, the airway remains open, but the nerve signals controlling the respiratory muscles are not regulated properly. This loss of regulation can cause wide fluctuations in the level of carbon dioxide (CO₂) in the blood. Normal activity in the body produces CO₂, which is brought by the blood to the lungs for exhalation. When the blood level of CO₂ rises, brain centers respond by increasing the rate of respiration, clearing the CO₂. As blood levels fall again, respiration slows down. Normally, this interaction of CO₂ and breathing rate maintains the CO₂ level within very narrow limits. CSA can occur when the regulation system becomes insensitive to CO₂ levels, allowing wide fluctuations in both CO₂ levels and breathing rates. High CO₂ levels cause very rapid breathing (hyperventilation), which then lowers CO₂ so much that breathing becomes very slow or even stops. CSA occurs during sleep because when a person is awake, breathing is usually stimulated by other signals, including conscious awareness of breathing rate.

A combination of the two forms is also possible, and is called "mixed sleep apnea." Mixed sleep apnea episodes usually begin with a reduced central respiratory drive, followed by obstruction.

OSA and CSA cause similar symptoms. The most common symptoms are:

• daytime sleepiness
• morning headaches
• a feeling that sleep is not restful
• disorientation upon waking
• memory loss and difficulty paying attention
• poor judgment
• personality changes

Sleepiness is caused not only by the frequent interruption of sleep, but by the inability to enter long periods of deep sleep, during which the body performs numerous restorative functions. OSA is one of the leading causes of daytime sleepiness, and is a major risk factor for motor vehicle accidents. Headaches and disorientation are caused by low oxygen levels during sleep, from the lack of regular breathing.

Other symptoms of sleep apnea may include sexual dysfunction , loss of concentration, memory loss , intellectual impairment, and behavioral changes including anxiety and depression .

Sleep apnea is also associated with night sweats and nocturia, or increased frequency of urination at night. Bedwetting in children is also linked to sleep apnea.

Sleep apnea can also cause serious changes in the cardiovascular system. Daytime hypertension (high blood pressure) is common. An increase in the number of red blood cells (polycythemia) is possible, as is an enlarged left ventricle of the heart (cor pulmonale), and left ventricular failure. In some people, sleep apnea causes life-threatening changes in the rhythm of the heart, including heartbeat slowing (bradycardia), racing (tachycardia), and other types of arrhythmias. Sudden death may occur from such arrhythmias. Patients with the Pickwickian syndrome (named after a Charles Dickens character) are obese and sleepy, with right heart failure, pulmonary hypertension, and chronic daytime low blood oxygen (hypoxemia) and increased blood CO₂ (hypercapnia).

Diagnosis

Excessive daytime sleepiness is the complaint that usually brings a person to see the doctor. A careful medical history will include questions about alcohol, tobacco, or tranquilizer use; family history; snoring (often reported by the person's partner); and morning headaches or disorientation. A physical examination will include examination of the mouth, nose and throat to look for narrowing or obstruction, or unusual size or shape of the tonsils or adenoids. Blood pressure is also measured. Measuring heart rate or blood levels of oxygen and CO₂ during the daytime will not usually be done, since these are abnormal only at night in most patients.

In some cases the person's dentist may suggest the diagnosis of OSA on the basis of a dental checkup or evaluation of the patient for oral surgery.

Confirmation of the diagnosis usually requires making measurements while the person sleeps. These tests are called a polysomnography study, and are conducted during an overnight stay in a specialized sleep laboratory. Important parts of the polysomnography study include measurements of:

• heart rate
• airflow at the mouth and nose
• respiratory effort
• sleep stage (light sleep, deep sleep, dream sleep, etc.)
• oxygen level in the blood, using a noninvasive probe (ear oximetry)

Simplified studies done overnight at home are also possible, and may be appropriate for people whose profile strongly suggests the presence of obstructive sleep apnea; that is, middle-aged, somewhat overweight men, who snore and have high blood pressure. The home-based study usually includes ear oximetry and cardiac measurements. If these measurements support the diagnosis of OSA, initial treatment is usually suggested without polysomnography. Home-based measurements are not used to rule out OSA, however, and if the measurements do not support the OSA diagnosis, polysomnography may be needed to define the problem further.

Treatment

Treatment of obstructive sleep apnea begins with reducing the use of alcohol or tranquilizers in the evening, if these have been contributing to the problem. Quitting smoking is recommended for a number of health concerns in addition to OSA. Weight loss is also effective, but if the weight returns, as it often does, so does the apnea. Changing sleeping position may be effective. Snoring and sleep apnea are both most common when a person sleeps on his back. Turning to sleep on the side may be enough to clear up the symptoms. Raising the head of the bed may also help.

There are few reports of OSA being treated by alternative and complementary approaches. In 2002, however, some Japanese researchers reported on the case of a 44-year-old male who was successfully treated for OSA by taking a Kampo extract, or traditional Japanese herbal formulation.

Allopathic treatment

Opening of the nasal passages can provide some relief for sleep apnea sufferers. There are a variety of nasal devices such as clips, tapes, or holders which may help, though discomfort may limit their use. Nasal decongestants may be useful, but should not be taken for sleep apnea without the consent of the treating physician. Supplemental nighttime oxygen can be useful for some people with either central and obstructive sleep apnea. Tricyclic antidepressant drugs such as protriptyline (Vivactil) may help by increasing the muscle tone of the upper airway muscles, but their side effects may severely limit their usefulness.

For moderate to severe sleep apnea, the most successful treatment is nighttime use of a ventilator, called a CPAP machine. CPAP (continuous positive airway pressure) blows air into the airway continuously, preventing its collapse. CPAP requires the use of a nasal mask. The appropriate pressure setting for the CPAP machine is determined by polysomnography in the sleep lab. Its effects are dramatic; daytime sleepiness usually disappears within one to two days after treatment begins. CPAP is used to treat both obstructive and central sleep apnea.

CPAP is tolerated well by about two-thirds of patients who try it. Bilevel positive airway pressure (BiPAP), is an alternative form of ventilation. With BiPAP, the ventilator reduces the air pressure when the person exhales. This form of treatment is more comfortable for some.

Another approach to treating OSA involves the use of oral appliances intended to improve breathing either by holding the tongue in place or by pushing the lower jaw forward during sleep to increase the air volume in the upper airway. The first type of oral appliance is known as a tongue retaining device or TRD. The second type is variously called an oral protrusive device (OPD) or mandibular advancement splint (MAS), because it holds the mandible, or lower jaw, forward during sleep. These oral devices appear to work best for patients with mild-to-moderate OSA, and in some cases can postpone or prevent the need for surgery. Their rate of patient compliance is about 50%; most patients who stop using oral appliances do so because their teeth are in poor condition. TRDs and OPDs can be fitted by dentists; however, most dentists work together with the patient's physician following a polysomnogram rather than prescribing the device by themselves.

Surgery can be used to correct obstructions in the airway. The most common surgery is called UPPP, for uvulopalatopharynoplasty. This surgery removes tissue from the rear of the mouth and top of the throat. The tissues removed include parts of the uvula (the flap of tissue that hangs down at the back of the mouth), the soft palate, and the pharynx. Tonsils and adenoids are usually removed as well. This operation significantly improves sleep apnea in slightly more than half of all cases. More recently, oral surgeons have been performing region-specific surgery for OSA, which grew out of the recognition that obstructions may exist in more than one level of the patient's upper airway. Region-specific surgery has a cure rate of over 90%, though it may involve more than one surgical operation.

A modified tracheotomy may also be performed to treat OSA. This procedure involves the surgical placement of a tiny breathing tube that fits in a 2 mm incision in the throat.

Reconstructive surgery is possible for those whose OSA is due to constriction of the airway by lower jaw deformities. Genioplasty, which is a procedure that plastic surgeons usually perform to reshape a patient's chin to improve his or her appearance, is now being done to reshape the upper airway in patients with OSA.

Expected results

Appropriate treatment enables most people with sleep apnea to be treated successfully, although it may take some time to determine the most effective and least intrusive treatment. In many cases consultation and cooperation between the person's physician and dentist help in finding the best treatment option. Polysomnography testing is usually required after beginning a treatment to determine how effective it has been.

Prevention

For people who snore frequently, weight control, smoking cessation, avoidance of evening alcohol or tranquilizers, and adjustment of sleeping position may help reduce the risk of developing obstructive sleep apnea.

Resources

BOOKS

"Disorders of the Oral Region." Section 9, Chapter 105 in The Merck Manual of Diagnosis and Therapy, edited by Mark H. Beers, MD, and Robert Berkow, MD. Whitehouse Station, NJ: Merck Research Laboratories, 1999.

Pascualay, Ralph, and Sally Warren Soest. Snoring and Sleep Apnea, 2nd ed. New York, NY: Demos Vermande, 1996.

"Sleep Disorders." Section 14, Chapter 173 in The Merck Manual of Diagnosis and Therapy, edited by Mark H. Beers, MD, and Robert Berkow, MD. Whitehouse Station, NJ: Merck Research Laboratories, 1999.

PERIODICALS

Chasens, E. R., and M. G. Umlauf. "Nocturia: A Problem That Disrupts Sleep and Predicts Obstructive Sleep Apnea" Geriatric Nursing 24 (March-April 2003): 76–81, 105.

Chung, S. A., S. Jairam, M. R. Hussain, and C. M. Shapiro. "How, What, and Why of Sleep Apnea. Perspectives for Primary Care Physicians." Canadian Family Physician 48 (June 2002): 1073–1080.

Edwards, N., P. G. Middleton, D. M. Blyton, and C. E. Sullivan. "Sleep Disordered Breathing and Pregnancy." Thorax 57 (June 2002): 555–558.

Hisanaga, A., T. Itoh, Y. Hasegawa, et al. "A Case of Sleep Choking Syndrome Improved by the Kampo Extract of Hange-Koboku-To." Psychiatry and Clinical Neuro-science 56 (June 2002): 325–327.

Kapur, V., K. P. Strohl, S. Redline, et al. "Underdiagnosis of Sleep Apnea Syndrome in U.S. Communities." Sleep and Breathing 6 (June 2002): 49–54.

Koliha, C. A. "Obstructive Sleep Apnea in Head and Neck Cancer Patients Post Treatment … Something to Consider?" ORL—Head and Neck Nursing 21 (Winter 2003): 10–14.

Neill, A., R. Whyman, S. Bannan, et al. "Mandibular Advancement Splint Improves Indices of Obstructive Sleep Apnoea and Snoring but Side Effects Are Common." New Zealand Medical Journal 115 (June 21, 2002): 289–292.

Rose, E., R. Staats, J. Schulte-Monting, et al. "Long-Term Compliance with an Oral Protrusive Appliance in Patients with Obstructive Sleep Apnoea." [in German] Deutsche medizinische Wochenschrift 127 (June 7, 2002): 1245–1249.

Shiomi, T., A. T. Arita, R. Sasanabe, et al. "Falling Asleep While Driving and Automobile Accidents Among Patients with Obstructive Sleep Apnea-Hypopnea Syndrome." Psychiatry and Clinical Neuroscience 56 (June 2002): 333–334.

Stanton, D. C. "Genioplasty." Facial Plastic Surgery 19 (February 2003): 75–86.

Umlauf, M. G., and E. R. Chasens. "Bedwetting—Not Always What It Seems: A Sign of Sleep-Disordered Breathing in Children." Journal for Specialists in Pediatric Nursing 8 (January-March 2003): 22–30.

Veale, D., G. Poussin, F. Benes, et al. "Identification of Quality of Life Concerns of Patients with Obstructive Sleep Apnoea at the Time of Initiation of Continuous Positive Airway Pressure: A Discourse Analysis." Quality of Life Research 11 (June 2002): 389–399.

Viera, A. J., M. M. Bond, and S. J. Yates. "Diagnosing Night Sweats." American Family Physician 67 (March 1, 2003): 1019–1024.

ORGANIZATIONS

American Academy of Otolaryngology, Head and Neck Surgery, Inc. One Prince Street, Alexandria, VA 22314-3357. (703) 836-4444. <http://www.entnet.org>.

American Dental Association. 211 East Chicago Avenue, Chicago, IL 60611. (312) 440-2500. <www.ada.org>.

American Sleep Apnea Association. 1424 K Street NW, Suite 302, Washington, DC 20005. (202) 293-3650. Fax: (202) 293-3656. <www.sleepapnea.org>.

Canadian Coordinating Office for Health Technology Assessment. <www.ccohta.ca/pubs/english/sleep/treatmnt>.

National Sleep Foundation. 1522 K Street, NW, Suite 500, Washington, DC 20005. <www.sleepfoundation.org>.

OTHER

American Sleep Apnea Association (ASAA). Considering Surgery for Snoring? <http://www.sleepapnea.org/snoring.html>.

National Heart, Lung, and Blood Institute (NHLBI). Facts About Sleep Apnea. NIH Publication No. 95-3798. <http://www.nhlbi.nih.gov/health/public/sleep/sleepapn.htm>.

Paula Ford-Martin

Rebecca J. Frey, PhD

Sleep Apnea

Definition

Sleep apnea is a condition in which breathing stops for more than ten seconds during sleep. Sleep apnea is a major, though often unrecognized, cause of daytime sleepiness. It can have serious negative effects on a person's quality of life, and is thought to be considerably underdiagnosed in the United States.

Description

A sleeping person normally breathes continuouusly and uninterruptedly throughout the night. A person with sleep apnea, however, has frequent episodes (up to 400-500 per night) in which he or she stops breathing. This interruption of breathing is called "apnea." Breathing usually stops for about 30 seconds; then the person usually startles awake with a loud snort and begins to breathe again, gradually falling back to slep.

There are two forms of sleep apnea. In obstructive sleep apnea (OSA), breathing stops because tissue in the throat closes off the airway. In central sleep apnea, (CSA), the brain centers responsible for breathing fail to send messages to the breathing muscles. OSA is much more common than CSA. It is thought that about 1-10% of adults are affected by OSA; only about one tenth of that number have CSA. OSA can affect people of any age and of either sex, but it is most common in middle-aged, somewhat overweight men, especially those who use alcohol.

Causes and symptoms

Obstructive sleep apnea

Obstructive sleep apnea occurs when part of the airway is closed off (usually at the back of the throat) while a person is trying to inhale during sleep. People whose airways are slightly narrower than average are more likely to be affected by OSA. Obesity, especially obesity in the neck, can increase the risk of developing OSA, because the fat tissue tends to narrow the airway. In some people, the airway is blocked by enlarged tonsils, an enlarged tongue, jaw deformities, or growths in the neck that compress the airway. Blocked nasal passages may also play a part in some people.

When a person begins to inhale, the expansion of the lungs lowers the air pressure inside the airway. If the muscles that keep the airway open are not working hard enough, the airway narrows and may collapse, shutting off the supply of air to the lungs. OSA occurs during sleep because the neck muscles that keep the airway open are not as active then. Congestion in the nose can make collapse more likely, since the extra effort needed to inhale will lower the pressure in the airway even more. Drinking alcohol or taking tranquilizers in the evening worsens this situation, because these cause the neck muscles to relax. (These drugs also lower the "respiratory drive" in the nervous system, reducing breathing rate and strength.)

People with OSA almost always snore heavily, because the same narrowing of the airway that causes snoring can also cause OSA. Snoring may actually help cause OSA as well, because the vibration of the throat tissues can cause them to swell. However, most people who snore do not go on to develop OSA.

Other risk factors for developing OSA include male sex; pregnancy; a family history of the disorder; and smoking. With regard to gender, it has been found that male sex hormones sometimes cause changes in the size or structure of the upper airway. The weight gain that accompanies pregnancy can affect a woman's breathing patterns during sleep, particularly during the third trimester. With regard to family history, OSA is known to run in families even though no gene or genes associated with the disorder have been identified as of 2002. Smoking increases the risk of developing OSA because it causes inflammation, swelling, and narrowing of the upper airway.

Some patients being treated for head and neck cancer develop OSA as a result of physical changes in the muscles and other tissues of the neck and throat. Doctors recommend prompt treatment of the OSA to improve the patient's quality of life.

Central sleep apnea

In central sleep apnea, the airway remains open, but the nerve signals controlling the respiratory muscles are not regulated properly. This can cause wide fluctuations in the level of carbon dioxide (CO₂) in the blood. Normal activity in the body produces CO₂, which is brought by the blood to the lungs for exhalation. When the blood level of CO₂ rises, brain centers respond by increasing the rate of respiration, clearing the CO₂. As blood levels fall again, respiration slows down. Normally, this interaction of CO₂ and breathing rate maintains the CO₂ level within very narrow limits. CSA can occur when the regulation system becomes insensitive to CO₂ levels, allowing wide fluctuations in both CO₂ levels and breathing rates. High CO₂ levels cause very rapid breathing (hyperventilation), which then lowers CO₂ so much that breathing becomes very slow or even stops. CSA occurs during sleep because when a person is awake, breathing is usually stimulated by other signals, including conscious awareness of breathing rate.

A combination of the two forms is also possible, and is called mixed sleep apnea. Mixed sleep apnea episodes usually begin with a reduced central respiratory drive, followed by obstruction.

OSA and CSA cause similar symptoms. The most common symptoms are:

• daytime sleepiness
• morning headaches
• a feeling that sleep is not restful
• disorientation upon waking
• poor judgment
• personality changes

Sleepiness is caused not only by the frequent interruption of sleep, but by the inability to enter long periods of deep sleep, during which the body performs numerous restorative functions. OSA is one of the leading causes of daytime sleepiness, and is a major risk factor for motor vehicle accidents. Headaches and disorientation are caused by low oxygen levels during sleep, from the lack of regular breathing.

Other symptoms of sleep apnea may include sexual dysfunction, loss of concentration, memory loss, intellectual impairment, and behavioral changes including anxiety and depression.

Sleep apnea is also associated with night sweats and nocturia, or increased frequency of urination at night. Bedwetting in children is also linked to sleep apnea.

Sleep apnea can also cause serious changes in the cardiovascular system. Daytime hypertension (high blood pressure) is common. An increase in the number of red blood cells (polycythemia) is possible, as is an enlarged left ventricle of the heart (cor pulmonale ), and left ventricular failure. In some people, sleep apnea causes life-threatening changes in the rhythm of the heart, including heartbeat slowing (bradycardia), racing (tachycardia), and other types of "arrhythmias." Sudden death may occur from such arrhythmias. Patients with the Pickwickian syndrome (named after a Charles Dickens character) are obese and sleepy, with right heart failure, pulmonary hypertension, and chronic daytime low blood oxygen (hypoxemia) and increased blood CO₂ (hypercapnia).

Diagnosis

Excessive daytime sleepiness is the complaint that usually brings a person to see the doctor. A careful medical history will include questions about alcohol or tranquilizer use, snoring (often reported by the person's partner), and morning headaches or disorientation. A physical exam will include examination of the throat to look for narrowing or obstruction. Blood pressure is also measured. Measuring heart rate or blood levels of oxygen and CO₂ during the daytime will not usually be done, since these are abnormal only at night in most patients.

In some cases the person's dentist may suggest the diagnosis of OSA on the basis of a dental checkup or evaluation of the patient for oral surgery.

Confirmation of the diagnosis usually requires making measurements while the person sleeps. These tests are called a polysomnography study, and are conducted during an overnight stay in a specialized sleep laboratory. Important parts of the polysomnography study include measurements of:

• heart rate
• airflow at the mouth and nose
• respiratory effort
• sleep stage (light sleep, deep sleep, dream sleep, etc.)
• oxygen level in the blood, using a noninvasive probe (ear oximetry)

Simplified studies done overnight at home are also possible, and may be appropriate for people whose profile strongly suggests the presence of obstructive sleep apnea; that is, middle-aged, somewhat overweight men, who snore and have high blood pressure. The home-based study usually includes ear oximetry and cardiac measurements. If these measurements support the diagnosis of OSA, initial treatment is usually suggested without polysomnography. Home-based measurements are not used to rule out OSA, however, and if the measurements do not support the OSA diagnosis, polysomnography may be needed to define the problem further.

Both types of studies are usually covered by insurance with the appropriate referral from a physician. Without insurance, lab-based polysomnography cost approximately $1,500 in 1997, while overnight home monitoring cost between $500 and $1,000.

Treatment

Behavioral changes

Treatment of obstructive sleep apnea begins with reducing the use of alcohol or tranquilizers in the evening, if these have been contributing to the problem. Weight loss is also effective, but if the weight returns, as it often does, so does the apnea. Changing sleeping position may be effective; snoring and sleep apnea are both most common when a person sleeps on his back. Turning to sleep on the side may be enough to clear up the symptoms. Raising the head of the bed may also help. Opening of the nasal passages can provide some relief. There are a variety of nasal devices such as clips, tapes, or holders which may help, though discomfort may limit their use. Nasal decongestants may be useful, but should not be taken for sleep apnea without the consent of the treating physician.

Oxygen and drug therapy

Supplemental nighttime oxygen can be useful for some people with either central and obstructive sleep apnea. Tricyclic antidepressant drugs such as protriptyline (Vivactil) may help by increasing the muscle tone of the upper airway muscles, but their side effects may severely limit their usefulness.

Mechanical ventilation

For moderate to severe sleep apnea, the most successful treatment is nighttime use of a ventilator, called a CPAP machine. CPAP (continuous positive airway pressure) blows air into the airway continuously, preventing its collapse. CPAP requires the use of a nasal mask. The appropriate pressure setting for the CPAP machine is determined by polysomnography in the sleep lab. Its effects are dramatic; daytime sleepiness usually disappears within one to two days after treatment begins. CPAP is used to treat both obstructive and central sleep apnea.

CPAP is tolerated well by about two-thirds of patients who try it. Bilevel positive airway pressure (BiPAP), is an alternative form of ventilation. With BiPAP, the ventilator reduces the air pressure when the person exhales. This is more comfortable for some.

Surgery

Surgery can be used to correct obstructions in the airways. The most common surgery is called UPPP, for uvulopalatopharngyoplasty. This surgery removes tissue from the rear of the mouth and top of the throat. The tissues removed include parts of the uvula (the flap of tissue that hangs down at the back of the mouth), the soft palate, and the pharynx. Tonsils and adenoids are usually removed in this operation. This operation significantly improves sleep apnea in slightly more than half of all cases.

Reconstructive surgery is possible for those whose OSA is due to constriction of the airway by lower jaw deformities. Genioplasty, which is a procedure that plastic surgeons usually perform to reshape a patient's chin to improve his or her appearance, is now being done to reshape the upper airway in patients with OSA.

When other forms of treatment are not successful, obstructive sleep apnea may be treated by a tracheostomy. In this procedure, an opening is made into the trachea (windpipe) below the obstruction, and a tube inserted to maintain an air passage. A tracheostomy requires a great deal of care to prevent infection of the tracheostomy site. In addition, since air is no longer being filtered and moistened by the nasal passages before entering the lungs, the lower airways can become dry and susceptible to infection as well. Tracheostomy is usually reserved for those whose apnea has led to life-threatening heart arrhythmias, and who have not been treated successfully with other treatments.

Oral appliances

Another approach to treating OSA involves the use of oral appliances intended to improve breathing either by holding the tongue in place or by pushing the lower jaw forward during sleep to increase the air volume in the upper airway. The first type of oral appliance is known as a tongue retaining device or TRD. The second type is variously called an oral protrusive device (OPD) or mandibular advancement splint (MAS), because it holds the mandible, or lower jaw, forward during sleep. These oral devices appear to work best for patients with mild-to-moderate OSA, and in some cases can postpone or prevent the need for surgery. Their rate of patient compliance is about 50%; most patients who stop using oral appliances do so because their teeth are in poor condition. TRDs and OPDs can be fitted by dentists; however, most dentists work together with the patient's physician following a polysomnogram rather than prescribing the device by themselves.

Prognosis

The combination of behavioral changes, ventilation assistance, drug therapy, and surgery allow most people with sleep apnea to be treated successfully, although it may take some time to determine the most effective and least intrusive treatment. Polysomnography testing is usually required after beginning a treatment to determine how effective it has been.

KEY TERMS

Continuous positive airway pressure (CPAP)— A ventilation system that blows a gentle stream of air into the nose to keep the airway open.

Genioplasty— An operation performed to reshape the chin. Genioplasties are often done to treat OSA because the procedure changes the structure of the patient's upper airway.

Mandible— The medical term for the lower jaw. One type of oral appliance used to treat OSA pushes the mandible forward in order to ease breathing during sleep.

Nocturia— Excessive need to urinate at night. Nocturia is a symptom of OSA and often increases the patient's daytime sleepiness.

Polysomnography— A group of tests administered to analyze heart, blood, and breathing patterns during sleep.

Tracheotomy— A surgical procedure in which a small hole is cut into the trachea, or windpipe, below the level of the vocal cords.

Uvulopalatopharyngoplasty (UPPP)— An operation to remove excess tissue at the back of the throat to prevent it from closing off the airway during sleep.

Prevention

For people who snore frequently, weight control, avoidance of evening alcohol or tranquilizers, and adjustment of sleeping position may help reduce the risk of developing obstructive sleep apnea.

Resources

BOOKS

Beers, Mark H., MD, and Robert Berkow, MD., editors. "Disorders of the Oral Region." Section 9, Chapter 105 In The Merck Manual of Diagnosis and Therapy. Whitehouse Station, NJ: Merck Research Laboratories, 2004.

Beers, Mark H., MD, and Robert Berkow, MD., editors. "Sleep Disorders." Section 14, Chapter 173 In The Merck Manual of Diagnosis and Therapy. Whitehouse Station, NJ: Merck Research Laboratories, 2004.

PERIODICALS

Chasens, E. R., and M. G. Umlauf. "Nocturia: A Problem That Disrupts Sleep and Predicts Obstructive Sleep Apnea" Geriatric Nursing 24 (March-April 2003): 76-81, 105.

Chung, S. A., S. Jairam, M. R. Hussain, and C. M. Shapiro. "How, What, and Why of Sleep Apnea. Perspectives for Primary Care Physicians." Canadian Family Physician 48 (June 2002): 1073-1080.

Edwards, N., P. G. Middleton, D. M. Blyton, and C. E. Sullivan. "Sleep Disordered Breathing and Pregnancy." Thorax 57 (June 2002): 555-558.

Hisanaga, A., T. Itoh, Y. Hasegawa, et al. "A Case of Sleep Choking Syndrome Improved by the Kampo Extract of Hange-Koboku-To." Psychiatry and Clinical Neuroscience 56 (June 2002): 325-327.

Kapur, V., K. P. Strohl, S. Redline, et al. "Underdiagnosis of Sleep Apnea Syndrome in U.S. Communities." Sleep and Breathing 6 (June 2002): 49-54.

Koliha, C. A. "Obstructive Sleep Apnea in Head and Neck Cancer Patients Post Treatment … Something to Consider?" ORL—Head and Neck Nursing 21 (Winter 2003): 10-14.

Neill, A., R. Whyman, S. Bannan, et al. "Mandibular Advancement Splint Improves Indices of Obstructive Sleep Apnoea and Snoring but Side Effects Are Common." New Zealand Medical Journal 115 (June 21, 2002): 289-292.

Rose, E., R. Staats, J. Schulte-Monting, et al. "Long-Term Compliance with an Oral Protrusive Appliance in Patients with Obstructive Sleep Apnoea." [in German] Deutsche medizinische Wochenschrift 127 (June 7, 2002): 1245-1249.

Shiomi, T., A. T. Arita, R. Sasanabe, et al. "Falling Asleep While Driving and Automobile Accidents Among Patients with Obstructive Sleep Apnea-Hypopnea Syndrome." Psychiatry and Clinical Neuroscience 56 (June 2002): 333-334.

Stanton, D. C. "Genioplasty." Facial Plastic Surgery 19 (February 2003): 75-86.

Umlauf, M. G., and E. R. Chasens. "Bedwetting—Not Always What It Seems: A Sign of Sleep-Disordered Breathing in Children." Journal for Specialists in Pediatric Nursing 8 (January-March 2003): 22-30.

Veale, D., G. Poussin, F. Benes, et al. "Identification of Quality of Life Concerns of Patients with Obstructive Sleep Apnoea at the Time of Initiation of Continuous Positive Airway Pressure: A Discourse Analysis." Quality of Life Research 11 (June 2002): 389-399.

Viera, A. J., M. M. Bond, and S. J. Yates. "Diagnosing Night Sweats." American Family Physician 67 (March 1, 2003): 1019-1024.

ORGANIZATIONS

American Academy of Otolaryngology, Head and Neck Surgery, Inc. One Prince Street, Alexandria, VA 22314-3357. (703) 836-4444. 〈http://www.entnet.org〉.

American Dental Association. 211 East Chicago Avenue, Chicago, IL 60611. (312) 440-2500. 〈www.ada.org〉.

American Sleep Apnea Association. 1424 K Street NW, Suite 302, Washington, DC 20005. (202) 293-3650. Fax: (202) 293-3656. 〈www.sleepapnea.org〉.

Canadian Coordinating Office for Health Technology Assessment. 〈www.ccohta.ca/pubs/english/sleep/treatmnt〉.

National Sleep Foundation. 1522 K Street, NW, Suite 500, Washington, DC 20005. 〈www.sleepfoundation.org〉.

OTHER

American Sleep Apnea Association (ASAA). Considering Surgery for Snoring? 〈http://www.sleepapnea.org/snoring.html〉.

National Heart, Lung, and Blood Institute (NHLBI). Facts About Sleep Apnea. NIH Publication No. 95-3798. 〈http://www.nhlbi.nih.gov/health/public/sleep/sleepapn.htm〉.

Sleep apnea

Definition

Sleep apnea, or sleep-disordered breathing, is a condition in which breathing is briefly interrupted or even stops episodically during sleep. Because repeated arousal or even full awakening when breathing stops disturbs sleep, individuals suffering from sleep apnea are often drowsy during the day. Complications from an insufficient amount of oxygen reaching the brain are serious and even potentially life threatening. Sleep apnea appears to be far more common than was initially realized when it was first described in 1965.

Description

The syndrome of sleep apnea is subdivided into two types: central and obstructive. Central sleep apnea, in which the brain does not properly signal respiratory muscles to begin breathing, is much less common than obstructive sleep apnea. In the latter condition, there are repeated episodes of upper airway obstruction during sleep, typically reducing blood oxygen saturation.

A distinctive form of obstructive sleep apnea is known as the Pickwickian syndrome, named after the protagonist in Charles Dickens' Pickwick Papers. Like that character, individuals with the Pickwickian syndrome are overweight, with large necks, fat buildup around the soft tissues of the neck, and loss of muscle tone with aging. When the neck muscles relax during sleep, these characteristics allow the windpipe to collapse during breathing, which usually causes loud snoring.

When the individual with obstructive sleep apnea attempts to inhale, this causes suction that collapses the windpipe and blocks air flow for 10–60 seconds. The resulting fall in blood oxygen level signals the brain to awaken the person enough to tighten the upper airway muscles and reopen the windpipe, resulting in a snort or gasp before snoring resumes. The entire cycle may occur repeatedly, as often as hundreds of times each night.

Demographics

Approximately 6–7% of the population of the United States, or 18 million Americans, are thought to have sleep apnea, but only 10 million have symptoms, and only 0.6 million have yet been diagnosed. In Americans aged 30–60 years, obstructive sleep apnea affects nearly one in four men and one in 10 women; men are twice as likely as women to have sleep apnea. As sleep apnea seldom occurs in premenopausal females, it is suggested that hormones may play some role in the disorder.

Other predisposing factors include age, as nearly 20–60% percent of the elderly may be affected; over-weight status or obesity; or use of alcohol or sedatives. Based on a 1995 study, elderly African Americans are more than twice as likely as elderly whites to suffer from sleep apnea. Some families appear to have increased incidence of sleep apnea.

Causes and symptoms

Causes of central sleep apnea include various severe and life-threatening lesions of the lower brainstem, which controls breathing. Examples include bulbar poliomyelitis , a form of polio affecting the brainstem; degenerative diseases; radiation treatment to the neck, damaging the lower brainstem; and severe arthritis of the cervical spine and/or base of the skull, putting pressure on the lower brainstem.

Symptoms of central sleep apnea include cessation of breathing during sleep, often causing frequent awakenings and complaints of insomnia. In central sleep apnea, breathing patterns may also be disrupted during wakefulness. Other symptoms may relate to the underlying neurological condition affecting the brainstem, and may include difficulty swallowing, change in voice, or limb weakness and numbness.

Normally, muscles in the upper throat keep this part of the airway open, allowing air to enter the lungs. Although these muscles relax somewhat during sleep, they retain enough tone to keep the passage open. If the passage is narrow, relaxation of throat muscles during sleep can obstruct, or block, the passage and hinder or prevent air from flowing into the lungs.

Individuals with obstructive sleep apnea may have airway obstruction because of excessive relaxation of throat muscles or because of an already narrowed passage.

Because many patients with obstructive sleep apnea have no major structural defects in the airway and are not obese, other factors such as disordered control of ventilation and changes in lung volume during sleep may play a role in causing the condition.

Soon after falling asleep, the patient with obstructive sleep apnea typically begins snoring heavily. The snoring continues for some time and may become louder before the apnea, during which breathing stops for 10–60 seconds. A loud snort or gasp ends the apnea, followed by more snoring in a recurrent pattern. Decreased oxygen level in the blood during the apneas may cause decreased alertness and other symptoms, while disturbance of the sleep pattern at night may cause daytime drowsiness.

Those with the Pickwickian syndrome have a large neck or collar size, nasal obstruction, a large tongue, a narrow airway, or certain shapes of the palate and jaw.

While patients with sleep apnea may not be aware of the problem, their spouse may seek medical assistance because they are frequently awakened by their partner's snoring, which may be described as loud, squeaky, or raspy. In other cases, the patient may seek help for fatigue , difficulty staying awake during the day, or falling asleep at inappropriate times.

Because of restless sleep and decreased oxygen supply to the brain, patients with sleep apnea may complain of impaired mental function, slowed reaction times, problems concentrating, memory loss, poor judgment, personality changes such as irritability or depression , morning headaches, and decreased interest in sex.

Additional symptoms may include excessive sweating during sleep, bedwetting, nightmares, dry mouth when awakening caused by sleeping with the mouth open, development of high blood pressure, and frequent upper respiratory infections. Young children with sleep apnea may have visible inward movement of the chest during sleep, learning problems, growth or developmental problems, and hyperactive behavior.

Drinking alcohol before bedtime or taking sleeping pills may increase the risk of apneic episodes, as may breathing through the mouth rather than the nose during sleep.

Severe obstructive sleep apnea may cause pulmonary hypertension, or increased pressure in lung arteries, eventually leading to heart failure. Other complications may include increased risk of cardiovascular disease, stroke , heart arrhythmias or irregular heartbeats, and disorders of immune function.

Diagnosis

Although sleep apnea has been more widely diagnosed in the past decade, experts estimate that at least 90–95% of cases remain undiagnosed. Reasons for this include vague, slowly developing symptoms that largely occur when the patient is sleeping; limited knowledge of the disease by physicians; and expensive, specialized testing needed for definitive diagnosis.

Talking to the patient and the spouse or parent is an important first step, but it may not be sufficient. Similarly, the physical examination often fails to reveal distinctive abnormalities. Helpful diagnostic aids may include a questionnaire asking about typical symptoms and sleep habits, and a detailed inspection of the mouth, neck, and throat. Arterial blood gases may reveal low oxygen or high carbon dioxide levels in the blood.

More recently, it has been recognized that obstructive sleep apnea can occur even in individuals of normal weight who lack the other distinctive features of the Pick-wickian syndrome. Up to 40% of people with obstructive sleep apnea are not obese.

When sleep apnea is suspected from characteristic symptoms and physical appearance, in many other cases, an overnight polysomnography (PSG) testing at a specialized sleep center may be suggested. During this test, breathing, brain waves, heartbeat, muscle tension, and eye movement are monitored through wires attached to the skin while the patient sleeps. Oxygen levels can be monitored through a device applied to a fingertip, and audio and/or video recordings may provide additional diagnostic information.

After the test, a physician trained in PSG testing analyzes the recordings to determine if sleep apnea or other conditions are present. In some cases, PSG can also be done at home after a sleep technologist attaches the wires and instructs the parent or other responsible adult on how to record sleep activity. Although portable PSG tests are less expensive and more convenient, they are subject to lost or inadequate recording, technical problems, and slightly lower diagnostic accuracy. Patients with inconclusive results on home studies and those with negative studies but persistent symptoms should have standard PSG testing in a sleep center.

Treatment team

The internist or family practitioner is often the first physician consulted because the earliest symptoms of sleep apnea are typically vague. If sleep apnea is suspected, the patient is usually referred to a neurologist or specialist in sleep disorders. Ear, nose, and throat specialists can help determine if there are characteristic abnormalities of the jaw or palate contributing to the problem, and in some cases they may perform corrective surgery if indicated. Lung specialists should manage severe cases of sleep apnea that result in pulmonary hypertension. Technicians involved in the diagnosis and treatment of sleep apnea may include PSG technicians and respiratory therapists.

Treatment

For mild cases of sleep apnea, simple measures may suffice, such as losing weight through a diet and exercise program, or preventing the person from sleeping on their back. More severe cases may need assisted breathing devices to wear at night or surgery to correct airway obstruction. Individuals with sleep apnea should avoid sedatives, sleeping pills, narcotics, and alcohol, especially at bedtime, as these central nervous system depressants can prevent them from awakening enough to keep breathing.

General suggestions to promote better sleep include good sleep habits, going to bed at a regular time each night, and arising at the same time each morning rather than sleeping late on weekends. Keeping the bedroom at a comfortable temperature is conducive to better sleep. Exercising 20–30 minutes each day, at least five to six hours before bedtime, may be helpful both for sleeping better and for weight loss.

Caffeine and related stimulants found in coffee, tea, chocolate, and some diet drugs and pain relievers should be avoided. Smoking disrupts sleep by causing early morning awakening in response to nicotine withdrawal. Alcohol reduces the amount of time spent in deep sleep and rapid eye movement (REM) sleep and proportionately increases time spent in the lighter stages of sleep, which are less refreshing.

To relax before bedtime, taking a warm bath, reading, or other restful bedtime ritual may be helpful. Sleeping until the sun rises helps the body's internal biological clock reset itself, as does daily exposure to an hour of morning sunlight. When unable to sleep despite these measures, it is better to read, watch television, or listen to soothing music rather than lying in bed awake, which can cause anxiety and worsen insomnia.

To keep the airway open during sleep, some individuals with obstructive sleep apnea need a device called nasal CPAP, or continuous positive airway pressure, which delivers air through a mask over the nose or over both the nose and mouth. This is considered to be the most effective and widely used therapy.

Complications of CPAP may include nasal congestion or dryness, discomfort related to wearing the mask, and feelings of claustrophobia. To relieve these problems, heated humidifiers to moisturize and warm the air, better fitting and more comfortable masks, or applying steroids within the nasal passages may be helpful. In patients who find it difficult to exhale against the increased pressure of CPAP, bilevel positive-pressure therapy may be equally effective.

Some investigators are studying mechanical devices inserted into the mouth during sleep to open the airway by moving the jaw forward. Although these oral appliances appear to prevent daytime sleepiness and sleep disordered breathing, they do not seem to be as effective as nasal CPAP. However, they may be a reasonable option for patients who are unwilling or unable to use nasal CPAP.

Obstructive sleep apnea in children may be caused by enlarged tonsils and adenoids and can be corrected by tonsillectomy. In adults, surgery to remove airway obstruction may be needed, depending on the anatomical structure. Excess tissue at the back of the throat may be removed in a procedure called an uvulopalatopharyngoplasty, or UPPP. Some cases may require repairing a deviated nasal septum, or other surgery to remove blockage of the nose or upper throat. Surgery to correct obstructive sleep apnea seems to be most effective when it is tailored to the individual's specific anatomical obstruction.

As a last resort, a tracheostomy can be performed, making an opening in the windpipe to bypass the obstructed airway during sleep. During the day, a valve over the opening is closed so the person can speak, and at night, the valve is opened to bypass the obstruction.

If brainstem injury or disease impairs respiratory drive, causing central sleep apnea, mechanical ventilation on a respirator may be needed to ensure continued breathing.

Medications being tested in sleep apnea include Provigil, a nonaddictive drug that improves daytime alertness. Side effects may include nausea and headaches. Decongestants may reduce airway obstruction related to nasal congestion. Results of a controlled trial published in November 2003 suggest that the cholinesterase inhibitor physostigmine may reduce apnea episodes.

Clinical trials

The National Institutes of Neurological Disorder and Stroke, the National Heart, Lung, and Blood Institute (NHLBI), and the National Institute on Aging all support sleep apnea research.

The National Institute of Child Health and Human Development (NICHD) is recruiting children and adolescents with obstructive sleep apnea or other obesity-related diseases for a trial of orlistat (Xenical, Hoffmann LaRoche). By preventing the action of digestive enzymes, this drug interferes with the absorption of approximately one-third of dietary fat. Study subjects may receive active medication or placebo, but all will be enrolled in a weight loss program, including nutrition education, behavioral self-monitoring strategies, and promotion of physical activity.

The APPLES study (apnea positive pressure long-term efficacy study), sponsored by the NHLBI, is recruiting patients with obstructive sleep apnea to determine the effectiveness of nasal CPAP therapy as compared with a similar-appearing control device that does not administer air delivered under positive pressure. Outcomes studied in this trial include mental function, mood, daytime sleepiness, and quality of life. Contact information is the office of study chair William C. Dement, MD, PhD, (650) 723-8131, or <http://apples.stanford.edu>.

The NHLBI is also planning a study of the outcomes of sleep disorders in men aged 65 years and older. It will look at whether sleep disorders such as obstructive sleep apnea are associated with increased risk of cardiovascular disease, falls, decreased physical function, impaired mental function, decreased bone density, fractures, and death.

Prognosis

Treating sleep apnea by eliminating the obstruction usually prevents and reverses complications such as pulmonary hypertension, high blood pressure, and heart disease. Individuals with obstructive sleep apnea who are unable or unwilling to tolerate CPAP may suffer from abnormal heart rhythms, reduced alertness, and sleep deprivation.

Left untreated, sleep apnea can profoundly reduce daytime functioning, work performance, social relationships, and quality of life. If patients fall asleep while driving or engaging in another potentially hazardous activity during the day, sleep apnea may be fatal. Severe, untreated sleep apnea doubles or even triples the risk of automobile accidents compared with the general population. These individuals are also at risk of sudden death from respiratory arrest during sleep.

Children with unrecognized obstructive sleep apnea may experience problems with learning, development, and behavior, as well as failure to grow, heart problems, and high blood pressure. Daytime sleepiness may cause personality changes, poor school performance, and difficulties with interpersonal relationships. Lagging development may lead to frustration and even depression.

Until additional research is carried out, it remains unclear if there is a "safe" number of apnea episodes, or how sleep apnea interacts with other causes of lung or heart failure. It appears that most patients with sleep apnea and heart or lung failure also have underlying diseases such as obstructive lung disease caused by smoking or asthma, severe obesity, or coronary artery disease.

Central sleep apnea usually has a poor prognosis related to the underlying injury or disease affecting the brainstem. Most patients with central sleep apnea require prolonged mechanical ventilation, which can also lead to many serious complications.

Special concerns

Sleep apnea is difficult to diagnose without expensive testing, can aggravate or cause heart and lung problems, often reduces function and quality of life, and may require invasive surgical procedures or long-term use of nasal CPAP. For all these reasons, prevention of obstructive sleep apnea is a worthwhile goal.

Weight reduction in overweight individuals and decreasing intake of alcohol and sedatives have independent health benefits as well as reducing risk of developing obstructive sleep apnea. In children with enlargement of the tonsils and adenoids, corrective surgery may reduce upper respiratory infections while preventing sleep apnea.

In experiments in rats, intermittent decreases in blood oxygen levels during sleep, similar to those seen with obstructive sleep apnea, cause degenerative changes in the hippocampus, a brain region involved in memory and learning. These degenerative changes in the brain are associated with deficits in maze learning. If similar changes occur in obstructive sleep apnea, this might explain decreased mental function observed with this disorder. Brain degeneration related to episodic decreases in oxygen levels would be another important reason to ensure that obstructive sleep apnea is diagnosed and effectively treated.

Although it is well recognized that sleep apnea is more common in men than in women, a study in October 2003 also suggested that men are far more likely than women to seek treatment at a specialized sleep clinic. Research is ongoing to determine the cause of gender differences in sleep apnea and to increase referrals of women to sleep centers where they may obtain appropriate care.

Resources

PERIODICALS

Boyer, S., and V. Kapur. "Role of Portable Sleep Studies for Diagnosis of Obstructive Sleep Apnea." Current Opinion in Pulmonary Medicine 2003 Nov 9(6): 465–70.

Durand, E., F. Lofaso, S. Dauger, G. Vardon, C. Gaultier, and J. Gallego. "Intermittent Hypoxia Induces Transient Arousal Delay in Newborn Mice." Journal of Applied Physiology 96 (March 2004): 1216–1222.

Fitzpatrick, M. F., H. McLean, A. M. Urton, A. Tan, D. O'Donnell, and H. S. Driver. "Effect of Nasal or Oral Breathing Route on Upper Airway Resistance during Sleep." European Respiratory Journal 22, no. 5 (November 2003): 827–32.

Gozal, D., B. W. Row, et al. "Temporal Aspects of Spatial Task Performance during Intermittent Hypoxia in the Rat: Evidence for Neurogenesis." European Journal of Neuroscience 2003 Oct 18(8): 2335–42.

Hedner, J., H. Kraiczi, Y. Peker, and P. Murphy. "Reduction of Sleep-Disordered Breathing after Physostigmine." American Journal of Respiratory and Critical Care Medicine (2003) 168: 1246–1251.

Jordan, A. S., and R. D. McEvoy. "Gender Differences in Sleep Apnea: Epidemiology, Clinical Presentation and Pathogenic Mechanisms." Sleep Medicine Review 2003 Oct 7(5): 377–89.

Jordan, A. S., D. P. White, and R. B. Fogel. "Recent Advances in Understanding the Pathogenesis of Obstructive Sleep Apnea." Current Opinion in Pulmonary Medicine 2003 Nov 9(6): 459–64.

Kao, Y. H., Y. Shnayder, and K. C. Lee. "The Efficacy of Anatomically Based Multilevel Surgery for Obstructive Sleep Apnea." Otolaryngology Head Neck Surgery 2003 Oct 129(4): 327–35.

Lim, J., T. Lasserson, J. Fleetham, and J. Wright. "Oral Appliances for Obstructive Sleep Apnea." Cochrane Database Systems Review 2003 (4): CD004435.

Moyer, C. A., S. S. Sonnad, S. L. Garetz, J. I. Helman, and R. D. Chervin. "Quality of Life in Obstructive Sleep Apnea: A Systematic Review of the Literature." Sleep Medicine 2001 Nov 2(6): 477–91.

Qureshi, A., and R. D. Ballard. "Obstructive Sleep Apnea." Journal of Allergy and Clinical Immunology 2003 Oct 112(4): 643–51.

Wolk, R., A. S. Shamsuzzaman, and V. K. Somers. "Obesity, Sleep Apnea, and Hypertension." Hypertension 2003 Nov 10.

WEBSITES

Clinical Trials (March 2, 2004). <http://www.clinicaltrials.gov/ct/action/GetStudy>.

HealthFinder PO Box 1133, Washington, DC 20013-1133. (March 1, 2004). http://www.healthfinder.gov/search/default.asp?ct=HFDocs&so=Rank%5Bd%5D%2CDocTitle&doclang=1&page=1&q1=sleep&apnea.

National Institute of Neurological Disorders and Stroke NIH Neurological Institute. PO Box 5801, Bethesda, MD 20824. (800) 352-9424. (March 2, 2004). http://www.ninds.nih.gov/search.htm?Text2=%27Sleep+apnea%27&Text1=Sleep+apnea.

National Sleep Foundation. When You Can't Sleep: The ABCs of ZZZs. 2002. February 22, 2004 (March 2, 2004). <http://www.sleepfoundation.org/publications/ZZZs.cfm>

Stanford University Medical Center 300 Pasteur Drive, Stanford, CA 94305. (650) 723-4000. (March 2, 2004). <http://www.stanford.edu/~dement/childapnea.html>.

U.S. National Library of Medicine 8600 Rockville Pike, Bethesda, MD 20894. (March 2, 2004). <http://www.nlm.nih.gov/medlineplus/ency/article/003997.htm>.

OTHER

Apneos Corporation 2033 Ralston Avenue #41, Belmont, CA 94002. (650) 591-2895. (March 2, 2004). <http://www.apneos.com>.

ORGANIZATIONS

The American Lung Association. 61 Broadway, 6th Floor, New York, NY 10006. (212) 315-8700. (March 2, 2004). <http://lungusa.org/diseases/sleepapnea.html>.

The Sleep Apnea Society of Alberta. c/o 911-78 Avenue SW, Calgary, AB T2V0T7. (800) 817-5337. (March 2, 2004). <http://www.sleep-apnea.ab.ca/prognosis.htm>.

Laurie Barclay

Sleep Apnea

Will He Snooze or Snore?

What Is Sleep Apnea?

Living with Sleep Apnea

Resources

Sleep apnea (AP-nee-a) is a disorder in which a person temporarily stops breathing while sleeping.

KEYWORDS

for searching the Internet and other reference sources

Breathing disorders

Obstructive sleep apnea

Respiratory system

Snoring

Will He Snooze or Snore?

James loved his grandfather, but he was dreading this year’s visit. When James shared his room with Grandpa last year, he did not sleep all week. Sometimes the snoring would stop, but then James had to hop out of bed to make sure his grandfather was breathing. Each time, Grandpa started breathing again after about 10 seconds, but he would choke and gasp for air before starting to snore again. In the morning, he had no memory of the nights noisy events.

When Grandpa arrived, the first thing he told James was that he would be a better roommate this year. His snoring had been caused by sleep apnea, and his doctor had given him a device to wear in his nose at night to make it easier for him to breathe.

What Is Sleep Apnea?

While sleeping, a person with sleep apnea stops breathing briefly, usually for about 10 seconds at a time. This can happen hundreds of times a night. The result is that the body does not get enough oxygen* or a restful night’s sleep. People with sleep apnea often are very tired during the day, have trouble concentrating, and may feel anxious and have difficulty falling asleep at night. Sometimes, they wake up in a panic, because they think they are choking, and many wake up with headaches and are depressed and moody.

* oxygen

(OK-si-jen) is an odorless, colorless gas essential for the human body. It is taken in through the lungs and delivered to the body by the bloodstream.

Snoring

One of the symptoms of sleep apnea is snoring. But snoring can have other causes, including drinking alcohol, taking sedative medication, chronic nasal congestion, or obstruction caused by enlarged adenoids (AD-e-noidz) and tonsils.

The most common cause of snoring is not known—some people just snore. Snoring is a symptom of sleep apnea only if the snoring is punctuated by extended quiet periods before snoring resumes.

Obstructive sleep apnea (OSA) is the most common type of sleep apnea. It occurs when something in the throat, such as the tongue or tonsils*, blocks the airway. Central sleep apnea occurs when the brain temporarily “forgets” to tell the body to breathe. Mixed apnea is a combination of OSA and central apnea.

* tonsils

(TON-silz) are paired clusters of lymphoid tissues in the throat.

People of all ages have sleep apnea, but it is most common in older people. OSA occurs most often in men over 50, and many people with OSA are overweight. People with sleep apnea often do not know that they have it. Family members, however, are well aware of the problem, because the most common symptom is loud snoring.

Living with Sleep Apnea

In some people, sleep apnea is just an annoying problem; in others, it can lead to heart problems and stroke*. To determine if someone has sleep apnea, doctors monitor the person while he or she sleeps. Sometimes, this is done at sleep clinics, which are special places where researchers measure people’s brain waves, heart rate, eye movement, body muscle tone, breathing, snoring, and blood oxygen levels while they sleep.

* stroke

is a blocked or ruptured blood vessel within the brain, which deprives some brain cells of oxygen and thereby kills or damages these cells. Also called apoplexy (AP-o-plek-see).

People with sleep apnea should not drink alcohol or take sleeping pills before bed, and they should try to lose weight if they are too heavy. For many people, sleeping on their sides eliminates, or at least lessens, snoring. Various prescription drugs relieve apnea in some people. Special devices worn in the nose or mouth can keep the airways clear as well. In some cases, surgery to remove tissues that block the airway (such as tonsils and adenoids) can be performed.

See also

Insomnia

Obesity

Sleep Disorders

Resources

SleepNet provides information and support for people with sleep apnea at its website. http://www.sleepnet.com

The Apnea Patient’s News, Education, and Awareness Network (APNEA Net) provides information and support for people with sleep apnea at its website. http://www.apneanet.org

APNEA

Apnea is a condition when breathing stops during sleep. Since common brain processes regulate both sleep and breath, respiration is controlled differently when we are awake and asleep. Breathing may stop because the brain fails to tell the muscles in the lungs to contract or expand (central apnea) or because of physical obstruction of the upper airway, with breathing muscles in the diaphragm and chest continuing to function (obstructive apnea), or both combined (mixed apnea). Apneic pauses as brief as two to six seconds normally occur in infants and children. If they last longer (say, fifteen to twenty seconds), occur frequently, and are accompanied by lowered blood oxygen levels (hypoxemia), the developing brain is deprived of needed oxygen. If untreated, this Obstructive Sleep Apnea Syndrome (OSAS) places a child at risk for mental deficits, heart and respiratory abnormalities, and even death. This respiratory dys-function has been associated with snoring, as well as upper respiratory infection, Down syndrome, Prader-Willi syndrome, Attention Deficit Hyperactivity Disorder (ADHD), epilepsy, and sudden infant death syndrome (SIDS). Protection against its effects can be provided by treatment with continuous positive airway pressure (CPAP) during sleeping as well as a number of drugs.

See also:SLEEPING

Bibliography

Carroll, John, and Gerald Loughlin. "Obstructive Sleep Apnea Syndrome in Infants and Children: Diagnosis and Management." In Richard Ferber and Meier Kryger eds., Principles and Practice of Sleep Medicine in the Child. Philadelphia: W. B. Saunders, 1995.

Evelyn B.Thoman