Obstructive sleep apnea
Highlights
Obstructive Sleep Apnea
Obstructive sleep apnea is a common sleep disorder. It occurs when tissues in the upper airways come too close to each other during sleep, temporarily blocking the inflow of air.
Who Is At Risk
Obstructive sleep apnea can develop in anyone at any age but most often occurs in people who are:
- Overweight
- Male
- Age 40 or older
- Smokers
Sleep Apnea Symptoms
Symptoms of sleep apnea include:
- Excessive daytime sleepiness
- Morning headaches
- Impaired emotional or mental functioning
- Snoring
Lifestyle Changes
Patients with sleep apnea may find these lifestyle changes helpful:
- Sleep on your side, not your back. Special pillows can help maintain this position.
- If you smoke, quit.
- Do not drink alcohol within 4 hours of bedtime.
- If you are overweight, even a small amount of weight loss may have a beneficial effect on sleep apnea symptoms.
Treatment
The treatment of obstructive sleep apnea depends in part on the severity of the condition. Treatment options include:
- Dental devices. Dental devices, also called oral appliances, are custom-made mouthpieces that help position the lower jaw and tongue during sleep. Dental devices may be helpful for mild cases of obstructive sleep apnea.
- Breathing devices. Continuous positive airway pressure (CPAP) devices are the most common treatment for moderate-to-severe obstructive sleep apnea. Although these devices can take some time to get used to, they are a very effective treatment.
- Surgery. Various surgical procedures may be recommended for severe cases of obstructive sleep apnea.
Introduction
Sleep apnea is a disorder in which a person stops breathing during the night, perhaps hundreds of times, usually for 10 seconds or longer, sometimes for as long as a minute. These gaps in breathing are called apneas. The word apnea means absence of breath.
Sleep apnea is usually accompanied by snoring. People might not even know they have the condition. It inevitably causes daytime sleepiness.
Sleep apnea is grouped into three categories:
- Obstructive
- Central
- Mixed
Another, less severe form of obstructed breathing, is called upper airway resistance syndrome (UARS).
Obstructive Sleep Apnea
Obstructive sleep apnea (OSA) occurs when tissues in the upper throat collapse at different times during sleep, thereby blocking the passage of air. In general, OSA occurs as follows:
- On its way to the lungs, air passes through the nose, mouth, and throat (the upper airway).
- Under normal conditions, the back of the throat is soft and tends to collapse inward as a person breathes.
- Dilator (widening) muscles work against this collapse to keep the airway open. Interference or abnormalities in this process cause air turbulence.
- If the tissues at the back of the throat collapse and become momentarily blocked, apnea occurs. Breath is temporarily stopped. In most cases the person is unaware of it, although sometimes they awaken and gasp for breath.
- In some cases, the interference is incomplete (called obstructive hypopnea) and causes continuous but slow and shallow breathing. In response, the throat vibrates and makes the sound of snoring. Snoring can occur whether a person breathes through the mouth or the nose. (Snoring also occurs without sleep apnea.)
- Apnea decreases the amount of oxygen in the blood, and eventually this lack of oxygen triggers the lungs to suck in air.
- At this point, the patient may make a gasping or snorting sound but does not usually fully wake up.
Obstructive sleep apnea is defined as five or more episodes of apnea or hypopnea per hour of sleep in individuals who have excessive daytime sleepiness. Patients with 15 or more episodes of apnea or hypopnea per hour of sleep are considered to have moderate-to-severe sleep apnea.
Central Sleep Apnea
Central sleep apnea is much less common. It is caused by some problem in the central nervous system, most likely a failure of the brain to signal the airway muscles to breathe. In such cases, oxygen levels drop abruptly and usually the sleeper wakes with a start. Often people with central sleep apnea recall waking up. They generally experience less sleepiness during the day than people with obstructive sleep apnea. Heart disease, and in particular heart failure, is the most common cause of central sleep apnea.
Mixed Apnea
Mixed apnea is the term used when central and obstructive sleep apneas occur together.
Upper Airway Resistance Syndrome (UARS)
Upper airway resistance syndrome (UARS) is a condition in which patients snore, wake frequently during the night, and have excessive daytime sleepiness. However, UARS patients do not have the breathing abnormalities that characterize sleep apnea and they do not show a reduction in blood oxygen levels. Unlike apnea, UARS is more likely to occur in women than in men. Treatments are similar to those of sleep apnea. It is not known if UARS has any serious health complications.
Healthy Sleep
In sleep studies, subjects spend about one-third of their time asleep, suggesting that most people need about 8 hours of sleep each day. Individual adults differ in the amount of sleep they need to feel well rested, however. Infants may sleep up to 16 hours a day.
The daily cycle of sleeping and waking is called the circadian rhythm. It's commonly referred to as the biologic clock. Circadian means "about a day." Hundreds of bodily functions follow biologic clocks, but sleeping and waking comprise the most prominent circadian rhythm. The sleeping and waking cycle is about 24 hours. (People who are confined to windowless homes, with no clocks or other time cues, sleep and wake on a slightly longer cycle.) The 24-hour circadian rhythm typically adheres to the following factors:
- Humans are designed for daytime activity and nighttime rest.
- There is a natural peak in sleepiness at mid-day, the traditional siesta time.
In addition, daily rhythms mix with other factors that may interfere or change individual patterns:
- The firing of nerve cells in the brain may be faster or slower in different individuals.
- The monthly menstrual cycle in women can shift the pattern.
- Light signals coming through the eyes reset the circadian cycles each day, so changes in season or various exposures to light and dark can unsettle the pattern. The importance of sunlight as a cue for circadian rhythms is dramatized by the problems experienced by people who are totally blind. They commonly have trouble sleeping and other rhythm disruptions.
The Response in the Brain to Light Signals
The response to light signals in the brain is an important key factor in sleep:
- Light signals travel to a tiny cluster of nerves in the hypothalamus in the center of the brain, the body's master clock, which is called the supra chiasmatic nucleus or SCN.
- This nerve cluster takes its name from its location. It sits just above (supra) the optic chiasm, a major junction for nerves transmitting information about light from the eyes.
- The approach of dusk each day prompts the SCN to signal the nearby pineal gland to produce the hormone melatonin.
- Melatonin is thought to act as the body's time-setting hormone. The longer a person is in darkness the longer the duration of melatonin secretion. Secretion can be diminished by staying in bright light. Melatonin also appears to trigger the need to sleep.
Sleep Cycles
Sleep consists of two distinct states that alternate in cycles and reflect differing levels of brain nerve cell activity:
Non-Rapid Eye Movement Sleep (NonREM). NonREM sleep is also termed quiet sleep. NonREM is further subdivided into three stages of progression:
- Stage 1 (light sleep)
- Stage 2 (so-called true sleep)
- Stage 3 - 4 (deep "slow-wave," or delta sleep)
With each descending stage, awakening becomes more difficult. It is not known what governs NonREM sleep in the brain. A balance between certain hormones, particularly growth and stress hormones, may be important for deep sleep.
Rapid Eye-Movement Sleep (REM). REM sleep is active sleep. Most vivid dreams occur in REM sleep. REM-sleep brain activity is comparable to that in waking, but the muscles are virtually paralyzed, possibly preventing people from acting out their dreams. In fact, except for vital organs like lungs and heart, the only muscles not paralyzed during REM are the eye muscles. REM sleep may be critical for learning and for day-to-day mood regulation. When people are sleep-deprived, their brains must work harder than when they are well rested.
The REM/NREM Cycle. The cycle between quiet (NonREM) and active (REM) sleep generally follows this pattern:
- After about 90 minutes of NonREM sleep, eyes move rapidly behind closed lids, giving rise to REM sleep.
- As sleep progresses the NonREM/REM cycle repeats.
- With each cycle, NonREM sleep becomes progressively lighter, and REM sleep becomes progressively longer, lasting from a few minutes early in sleep to perhaps an hour at the end of the sleep episode.
Symptoms
People with sleep apnea usually do not remember waking during the night.
Symptoms in Adults
Symptoms may include:
- Excessive daytime sleepiness. Generally, patients risk falling asleep during the day while performing routine activities such as reading, watching TV, sitting inactively, lying down, or riding in a car while a passenger or stopped for a few minutes in traffic. Usually, these brief episodes of sleep do not seem to relieve their overall sense of sleepiness.
- Morning headaches.
- Irritability and impaired mental or emotional functioning. These types of symptoms are directly related to interrupted sleep.
- Snoring. Bed partners may report very loud and interrupted snoring. Patients experience snoring associated with choking or gasps. This often occurs in a crescendo pattern with the loudest noises occurring at the very end. These findings are more likely to occur when lying down (supine position). Patients often suffer from frequent arousals during sleep because of snoring.
Symptoms in Children
Sleep apnea occurs in about 2% of children. They may have symptoms that differ from adults, including:
- Longer total sleep time than normal in some children, especially obese children or those with severe apnea.
- Snoring. (An estimated 3 - 12% of all children snore. However, not all of them have sleep apnea.)
- More effort in breathing (flaring nostrils, heaving chests, sweating). The chest may have an inward motion during sleep.
- Behavioral difficulties without any obvious cause, such as hyperactivity and inattention. (Some patients may even be misdiagnosed with attention-deficit hyperactivity disorder.)
- Irritability
- Bed-wetting
- Morning headaches
- Failure to grow and gain weight
Causes
Any structural abnormality in the face, skull, or airways that causes some obstruction or collapse in the upper airways and reduces air pressure can produce sleep apnea syndrome. Abnormalities in tissues that lie between the back of the mouth and the esophagus (food pipe) are one of the most common structural causes of sleep apnea. Enlarged soft palates (the base of the tongue and surrounding throat walls) are also associated with many cases of sleep apnea.
Nerve, Metabolic, and Mechanical Abnormalities
Researchers have identified several physiologic abnormalities that may play a role in causing sleep apnea or in making it worse. These include an inability to regulate levels of carbon dioxide, impaired brain and nervous system responsiveness to various chemical messengers, and poor reflexes or muscle tone in the upper airways. The underlying reasons for these disturbances and their connection to apnea require further study.
Obesity
Obesity is strongly associated with sleep apnea and is a cause of it in some cases. Imaging scans have shown fatty cells clogging the throat tissue, which indicates that they narrow the airways. In one study, the more obese a person with sleep apnea was, the higher the pressure on the airway and therefore the greater the obstruction of the airway. (Obstructive sleep apnea may also contribute to obesity itself, however, since a sleepy person tends to be sedentary.)
Sleep Behaviors
Snoring. Chronic snoring itself may actually be a cause of sleep apnea. Over time, the vibrations and the increased pressure against the upper airways as snoring people inhale may cause the soft palate to lengthen. This stretched palate is more prone to collapse and obstruction.
It should be stressed that snoring is very common. Snoring occurs in about a third of the population, while apnea, according to one study, occurs in only 6%. Snoring, then, does not always cause apnea, nor is it always a sign of the respiratory disorder. Furthermore, while snoring is also associated with daytime sleepiness regardless of whether apneas are present, snoring alone does not appear to pose any major health risks.
Mouth Breathing. Some evidence suggests that a tendency to breathe through the mouth (rather than the nose) during childhood can actually produce structural changes in the face (longer face, narrow jaw, receding chin). Such facial characteristics may eventually put people at risk for sleep apnea.
Causes of Sleep Apnea in Small Children
Sleep apnea occurs in about 2% of children and can occur even in very young children. The most likely causes are the following:
- Facial or skull abnormalities in infants.
- Overgrown tonsils, adenoids, or both in small children. (Removal of tonsils or adenoids can free the airways and solve the problem.)
- Premature infants also commonly have a form of apnea that may be related to lung or nervous system problems.
Risk Factors
Gender. More men than women appear to have sleep apnea. In the U.S., about 4% of men and 2% of women age 30 - 60 meet the criteria for obstructive sleep apnea. Such people have at lease five episodes of apnea or hypopnea (shallow nighttime breathing) for each hour of sleep plus excessive daytime sleepiness. A much higher percentage has just one of these two conditions.
Sleep apnea actually may be underdiagnosed in women, particularly older women. In general, older women have the same incidence of sleep apnea as men their own age. It is not clear why apnea occurs more often in men than women before menopause and why prevalence equalizes after menopause. Men tend to have larger necks and weigh more than women and women tend to gain weight and develop larger necks after menopause. However, studies have not found that these physical factors fully explain the differences in risk by gender in young adults or the increase in sleep apnea in postmenopausal women.
Age. Sleep apnea is most common in adults age 40 - 60 years old. Middle age is also when symptoms are worse. Nevertheless, sleep apnea affects people of all ages.
Ethnicity. African-Americans face a higher risk for sleep apnea than any other ethnic group in the United States. Other groups at increased risk include Pacific Islanders and Mexicans.
Being Obese
Obesity, especially having fat around the abdomen (the so-called apple shape), is a particular risk factor for sleep apnea, even in adolescents and children. However, many people with sleep-related breathing disorders, particularly women and small children, are not obese. Also, not all people who are obese have sleep apnea. Specific anatomical and physiological properties in the airways are more likely to be present in obese individuals with apnea.
Physical Characteristics
Having a Larger Neck. A large neck is a risk factor for sleep apnea. In fact, larger necks in men may be the primary reason for their higher risk for sleep apnea compared to women. A neck measurement of 17 inches or greater in men or at least 16 inches in women is one indicator that may suggest the condition. Postmenopausal women are more likely than younger women to have sleep apnea, in part because they tend to be heavier and have larger necks.
Specific Facial and Skull Characteristics. Structural abnormalities in the face and skull may be responsible for many cases of sleep apnea. These are likely to be the cause in many non-obese people with early-onset sleep apnea, particularly if they also have a family history of the problem.
Specific physical characteristics that may increase the risk for sleep apnea in both adults and children include:
- A long lower part of the face
- Brachycephaly, a birth defect in which the head tends to be shorter and wider than average
- A narrow upper jaw
- A receding chin
- An overbite
- A larger tongue
Characteristics in the Soft Palate. Some people have specific abnormalities in the soft area (palate) at the back of the mouth and throat that may lead to sleep apnea. These abnormalities include:
- The soft palate is stiffer, larger than normal, or both. An enlarged soft palate may be a significant risk factor for sleep apnea.
- The soft palate and the walls of the throat around it collapse easily.
Smoking and Alcohol Use
Smoking. Smokers are at higher risk for apnea. Those who smoke more than two packs a day have a risk 40 times greater than nonsmokers.
Alcohol. Alcohol use has been associated with apnea, although studies are mixed. Patients diagnosed with sleep apnea are recommended not to drink alcohol before bedtime.
Medical Conditions Related to Sleep Apnea
Diabetes. Diabetes is associated with sleep apnea and snoring. It is not clear if there is an independent relationship between the two conditions or whether obesity is the only common factor.
Gastroesophageal Reflux Disease (GERD). GERD is a condition caused by acid backing up into the esophagus. It is a common cause of heartburn. GERD and sleep apnea often coincide. Research suggests that the backup of stomach acid in GERD may produce spasms in the vocal cords (larynx), thereby blocking the flow of air to the lungs and causing apnea. Or, apnea itself may cause pressure changes that trigger GERD. Some evidence suggests that treating sleep apnea with continuous positive airway pressure (CPAP) may reduce GERD symptoms by nearly 50%. However, obesity is common in both conditions. More research is needed to clarify the association.
Polycystic Ovary Syndrome (PCOS). Obstructive sleep apnea and excessive daytime sleepiness appear to be associated with polycystic ovary syndrome (PCOS). About half of patients with PCOS also have diabetes. Obesity and diabetes are associated with both sleep apnea and PCOS and may be the common factors.
Prognosis
Sleep apnea has a strong association with several diseases, particularly those related to the heart and circulation.
Adverse Effects of Sleep Apnea on Heart and Circulation
A number of cardiovascular diseases -- including high blood pressure, heart failure, stroke, metabolic syndrome, and heart arrhythmias -- have an association with obstructive sleep apnea. This link may be because both cardiovascular illnesses and sleep apnea are associated with obesity and its consequences. However, large cohort observational studies have suggested that OSA itself may lead to incident cardiovascular disease. At this time, however, evidence of a clear causal relationship with any of these health problems is still weak. Some studies have found no significant independent risk for heart disease from obstructive sleep apnea. Likewise, whether treating obstructive sleep apnea decreases the incidence of any of these disorders remains to be proven.
High Blood Pressure. A number of studies have found a strong association between sleep apnea and high blood pressure (hypertension) even when obesity is not a factor. A weak, but still higher-than-normal, association with high blood pressure has also been observed in those who snore, wake frequently during the night, or have mild sleep apnea.
Coronary Artery Disease and Heart Attack. Sleep apnea has been associated with heart disease regardless of the presence of high blood pressure or other heart risk factors. Studies have shown that patients with moderate-to-severe obstructive sleep apnea have a higher risk for a heart attack.
Stroke. There is some association between the presence of sleep apnea and risk of death in patients who have previously had a stroke.
Heart Failure. Up to a third of patients with heart failure also have sleep apnea. Both central and obstructive sleep apnea are linked with heart failure. Obstructive sleep apnea can make heart failure worse, and patients with apnea have a higher mortality rate than those who do not. Treatment of obstructive sleep apnea may help improve heart function, although this is not certain.
Atrial Fibrillation. Sleep apnea is more common in people with atrial fibrillation (irregular heartbeat) than in patients with other heart conditions. In a 2005 study published in Circulation, 49% of patients with atrial fibrillation were at risk for developing apnea, compared with 32% of general cardiology patients. An earlier study indicated that patients with untreated obstructive sleep apnea may be at increased risk for recurrence of atrial fibrillation. Patients with atrial fibrillation who received CPAP treatment had a lower risk for recurrence.
Metabolic Syndrome. The metabolic syndrome (also called Syndrome X) is a cluster of abnormalities that cause insulin resistance. Some of these factors, including high blood pressure and obesity, are also associated with sleep apnea. Metabolic syndrome seems to be more common among patients with obstructive sleep apnea, possibly regardless of obesity.
Diabetes. Severe obstructive sleep apnea is associated with increased risk for developing type 2 diabetes.
Sleep Apnea as a Cause of Obesity
When it comes to sleep apnea and obesity, it is not always clear which condition is responsible for the other. For example, obesity is often a risk factor and possibly a cause of sleep apnea, but it is also likely that sleep apnea increases the risk for weight gain. Some studies indicate that sleep apnea disrupts rapid eye movement (REM) sleep, which, in turn, increases the risk for obesity. Research indicates that animals deprived of REM sleep tend to eat more.
Other Adverse Effects on Health
Sleep apnea is associated with a higher incidence of many medical conditions, other than heart and circulation. The links between apneas and the conditions are unclear.
- Pulmonary hypertension.
- Asthma. Sleep apnea may worsen asthma symptoms and interfere with the effectiveness of asthma medications. Treating the apnea may help asthma control.
- Liver damage in obese individuals with sleep apnea. Recent research suggests that severe apnea may increase the risk of liver disease regardless of weight.
- Seizures, epilepsy, and other nerve disorders. Sleep apnea appears to pose a particularly risk for nocturnal epilepsy, a condition in which seizures occur during sleep.
- Headaches. Sleep disorders, including apnea, may be the underlying causes of some chronic headaches. In some patients with both chronic headaches and apnea, treating the sleep disorder has cured the headache, even the very severe and disabling form known as a cluster headache.
- High-risk pregnancies. Sleep apnea causes higher rates of pregnancy complications, including gestational diabetes and high blood pressure.
- Eye disorders, including glaucoma, floppy eyelid syndrome, optic neuropathy conjunctivitis, dry eye, and various other infections and irritations. Some of these latter symptoms may be associated with CPAP treatment.
Psychological Effects
Studies report an association between severe apnea and psychological problems. The risk for depression rises with increasing severity of sleep apnea. Sleep-related breathing disorders can also worsen nightmares and post-traumatic stress disorder. Certainly, daytime sleepiness interferes with mental alertness and quality of life.
Effects on Bed Partners
Because sleep apnea so often includes noisy snoring, the condition can also adversely affect the sleep quality of a patient's bed partner. Spouses or partners may also suffer from sleeplessness and fatigue. In some cases, the snoring can disrupt relationships. Diagnosis and treatment of sleep apnea in the patient can help eliminate these problems.
Effects in Infants and Children
Failure to Thrive. Small children with undiagnosed sleep apnea may "fail to thrive," that is, they do not gain weight or grow at a normal rate and they have low levels of growth hormone. In severe cases, this may affect the heart and central nervous system.
Attention Deficits and Hyperactivity. Problems in attention and hyperactivity are common in children with sleep apnea. There is some evidence that such children may be misdiagnosed with attention-deficit hyperactivity disorder. Snoring, rather than sleepiness, is a stronger risk factor for hyperactivity in many of these children, especially boys under 8 years old. (Even children who snore and do not have sleep apnea may be at higher risk for poor concentration.)
Sleep Apnea and Automobile Accidents
Some researchers believe that sleepiness associated with sleep apnea is the greatest risk factor for car accidents. As many as 200,000 automobile accidents in the U.S. and 1,500 deaths from such accidents are caused by sleepiness. Studies continue to report that drowsy driving is as risky as drunk driving. Several studies have suggested that people with sleep apnea have two to three times as many car accidents, and five to seven times the risk for multiple accidents.
Diagnosis
Not all people with suspected sleep apnea need medical tests. Diagnostic testing may not be required for individuals who have no other health risk factors and whose suspected apnea does not affect their quality of life or safety on the road.
Doctors, however, should order diagnostic sleep studies if:
- The patient has a serious medical condition that might be worsened or caused by sleep apnea. Such conditions include heart disease, high blood pressure, heart failure, diabetes, chronic headaches, epilepsy, obstructive lung disease, or severe acid reflux (GERD).
- A child who shows signs of sleep apnea also has attention deficit problems or fails to thrive.
- The sleep apnea is severe enough to impair quality of life, increase the risk for accidents, or both.
In some cases of an uncertain diagnosis, high-risk patients may need to consult a sleep specialist or go to a sleep disorders center. At most centers, patients undergo an in-depth analysis, usually supervised by a multi-disciplinary team of consultants who can provide both physical and psychiatric evaluations. Centers should be accredited by the American Academy of Sleep Medicine.
Medical and Sleep History
To help determine the presence of sleep apnea, the doctor will ask the following questions:
- Is the patient taking any medications?
- How many periods of sleepiness are there each day and when do they occur? (Patients with apnea often do not describe this symptom as feeling "sleepy." They are more apt to describe this feeling as "lack of energy" or "feeling tired all day.")
- How restful is sleep?
- Do headaches occur regularly in the morning?
- Is the patient taking or withdrawing from stimulants, such as coffee or tobacco?
- How much alcohol is consumed per day?
- Does the patient have any problems with mental or emotional functioning?
- Does the patient suffer from heartburn?
- What is the normal sleeping position (back, side, or stomach)?
- If there is a sleeping partner, does he or she complain about the patient's snoring or gasping for breath? (Many times it is useful to interview the bed partner.)
Keeping a Record of Sleep. To help answer these questions, the patient may need to keep a sleep diary. Every day for 2 weeks, the patient should record all sleep-related information, including responses to questions listed above described on a daily basis. Recording sleep behavior using an extended-play audio or videotape can be very helpful in diagnosing sleep apnea.
Measuring Sleepiness
The Epworth Sleepiness Scale uses a simple questionnaire to measure excessive sleepiness during eight situations.
The Epworth Sleepiness Scale | |
Situation | Chance of Dozing 0 = no chance of dozing 1 = slight chance of dozing 2 = moderate chance of dozing 3 = high chance of dozing |
Sitting and reading. | (Indicate a score of 0 - 3) |
Watching TV. | (Indicate a score of 0 - 3) |
Sitting inactive in a public place (a theater or a meeting). | (Indicate a score of 0 - 3) |
As a passenger in a car for an hour without a break. | (Indicate a score of 0 - 3) |
Lying down to rest in the afternoon when circumstances permit. | (Indicate a score of 0 - 3) |
Sitting and talking to someone. | (Indicate a score of 0 - 3) |
Sitting quietly after a lunch without alcohol. | (Indicate a score of 0 - 3) |
In a car, while stopped for a few minutes in traffic. | (Indicate a score of 0 - 3) |
Score Results | 1 - 6: Getting enough sleep 4 - 8: Tends to be sleepy but is average. 9 - 15: Very sleepy and should seek medical advice. Over 16: Dangerously sleepy |
Physical Examination
To diagnose sleep apnea, the doctor will check for physical indications of sleep apnea, including:
- Abnormalities in the soft palate or upper airways, including enlarged tonsils
- Upper body obesity
- A wide neck measurement
Some evidence suggests that doctors may accurately identify nearly all cases of suspected sleep apnea using physical criteria, including taking measurements of body mass (the indication of obesity), neck circumference, and four areas inside the mouth.
Ruling out Other Disorders
If sleep apnea is not obvious after a physical examination and history, the doctor will need to rule out any other problems. These include sleep disorders, (such as narcolepsy, insomnia, or restless legs disorder), or any medical or psychologic conditions (chronic fatigue syndrome, depression) that may be causing daytime sleepiness.
Polysomnography and Home Sleep Studies
Polysomnography is the technical term for an overnight sleep study that involves recording brain waves and other sleep-related activity. Polysomnography involves many measurements and is typically performed at a sleep center.
The patient arrives about 2 hours before bedtime without having made any changes in daily habits. Polysomnography electronically monitors the patient as he or she passes, or fails to pass, through the various sleep stages.
Type 1 monitoring consists of full overnight polysomnography, with a minimum of two channels each for EEG, chin electromyogram, electrooculogram, as well as respiratory airflow (with thermistor or pressure-flow transducer), respiratory effort (thoracic and abdominal breathing movements), oximetry, and ECG or heart rate monitoring. With these components, polysomnography can track the following:
- Brain waves
- Body movements
- Breathing
- Heart rate
- Eye movements
Changes in breathing and blood oxygen levels are also recorded. In patients with suspected sleep apnea, the sleep expert will track instances of apnea and hypopnea that last longer than 10 seconds. In general, if there are more than five episodes per hour, apnea is significant and if there are more than 15, the condition is serious.
Overnight polysomnography has been the gold standard for diagnosing obstructive sleep apnea in both adults and children. It is very labor-intensive and expensive, however, and also misses snoring-induced arousals. After the diagnosis of sleep apnea is made, the patient must come back to the sleep center for another night in order to have CPAP started (CPAP titration).
Split night polysomnography. Because of the extra cost involved for a night at a sleep center, as well as limited resources available to diagnose and treat the many patients with obstructive sleep apnea, other methods have been developed in order to make diagnosis and initiation of treatment more efficient and less expensive. Split night polysomnography is one such technique. Based on criteria involving risk factors the patient may have, the severity of sleep apnea and whether it has been diagnosed in the first part of the evening, some patients may be progressed to titration for CPAP during the second part of the night. While this type of protocol is not fully accepted by all sleep centers, studies have demonstrated it to be effective when patients are chosen correctly and protocols are followed correctly.
Many doctors are suggesting moving towards home studies. One option is performing home studies first on patients considered to be at high probability for obstructive sleep apnea. Patients receive home sleep testing followed by auto titration of CPAP if necessary Patients who have a negative test or one that is not clear should have a follow-up in a sleep center for polysomnography. High quality studies have shown this to be effective.
Home Diagnostic Portable Devices
A number of portable devices are available, or being developed, so that patients have the convenience of being monitored at home. Experts hope that such monitors eventually will replace the need for overnight sleep clinics or the need for attended monitoring at home. These home devices can be very different from each other. Some are able to measure all the different factors that a sleep study performed at a sleep center is able to measure. Others are only able to measure some of them and may not get the full picture or accurate diagnosis.
Another concern that has been expressed is that there is no observation of the patient while asleep. As a result, the volume of the snoring, the position of the patient while sleeping, and any other unusual behaviors are not observed. While these data are not essential for the diagnosis of sleep apnea, they may be important in order to provide a complete picture.
Studies have shown that home sleep studies, especially those that measure most or all of the factors measured in a sleep center, are considered accurate for patients who are considered to be very likely to have sleep apnea after history and physical exam. It is important that these patients not have any complicating issues present.
A percentage of patients, however, will need to undergo polysomnography in the sleep center due to findings from a home study that cannot be interpreted clearly.
Unattended Monitoring with Auto-CPAP. This home monitoring method is a recent and simple technique for detecting impaired breathing. It uses an auto-CPAP machine, which is programmed to apply pressure through the airways via a tube that attaches to a mask that fits the nose. A monitor is attached that digitizes and records on a computer all the information on any apnea episodes during sleep.
Lifestyle Changes
Body position greatly affects the number and severity of episodes of obstructive sleep apnea, with at least twice as many apneas occurring in people who lay on their back as in those who sleep on their side. This may be due to the effects of gravity, which cause the throat to narrow when a person lies on the back. (Indeed, astronauts show a marked reduction in apneas and snoring in the weightlessness of space.) Positional sleep apnea affects people of all ages, including young children.
As a first step in dealing with sleep apnea, the patient should simply try rolling over onto the side. Patients who sleep on their backs and have 50 - 80 apneas per hour can sometimes nearly eliminate them when they shift to one side or the other. (Changing positions is less effective the more overweight a person is, but it still helps.)
Here are some suggestions that might help a person maintain a low-risk sleeping position:
- Sew a small pocket to the back of the pajamas and place a tennis ball or other small ball into it.
- A special pillow that helps to stretch the neck may reduce snoring and improve sleep for people with mild sleep apnea.
- Sleeping in an upright position may improve oxygen levels in overweight people with sleep apnea. Elevating the head of the bed may help.
Nasal Strips
Over-the-counter nasal strips, such as the Breathe Right strip or other devices that open the nostrils, are inexpensive and useful to prevent snoring. They may significantly improve early-stage sleep in people with sleep disorders associated with nasal obstruction and help reduce morning tiredness. They are not intended as treatments for sleep apnea, however.
Weight Loss
All patients with obstructive sleep apnea who are overweight should attempt a weight-reducing program. Weight loss certainly reduces snoring and apnea/hypopnea episodes in many people, sometimes stopping it completely. It also improves sleep and significantly reduces daytime sleepiness.
Smoking and Alcohol
- Smokers should quit, since smoking worsens apnea
- Alcohol should be avoided within 4 hours of sleep
Treatment
Treatment for sleep apnea depends on the severity of the problem. Given the data on the long-term complications of sleep apnea, it is important for patients to treat the problem as they would any chronic disease. Simply trying to treat snoring will not treat sleep apnea. Because of its association with heart problems and stroke, sleep apnea that does not respond to lifestyle measures should be treated by a doctor, ideally a sleep disorders specialist.
At this time, the most effective treatments for sleep apnea are devices that deliver slightly pressurized air to keep the throat open during the night. There are a number of such devices available.
Continuous Positive Airflow Pressure (CPAP)
The best treatment for severe obstructive and mixed sleep apnea is a system known as continuous positive airflow pressure (CPAP), sometimes referred to as nasal continuous positive airflow pressure (nCPAP). It is safe and effective in sleep apnea patients of all ages, including children. CPAP may not recommended for patients who have mild-to-moderate apnea as identified in sleep studies but who do not have daytime sleepiness, as they generally report little or no benefit from this treatment.
CPAP has been shown to be superior to oral appliances made and temperature-controlled radiofrequency tissue ablation. It has not been directly compared to tonsillectomy or uvulopalatopharyngoplasty in good quality studies. Overall, CPAP is considered first-line treatment for mild, moderate, or severe obstructive sleep apnea.
CPAP works in the following way:
- The device itself is a machine weighing about 5 pounds that fits on a bedside table.
- A mask containing a tube connects to the device and fits over just the nose.
- The machine supplies a steady stream of air through a tube and applies sufficient air pressure to prevent the tissues from collapsing during sleep
Effects on Sleep and Wakefulness. A major 2003 analysis confirmed the benefits of CPAP on both objective and subjective measures of sleep. After using CPAP regularly many patients report the following benefits:
- Restoration of normal sleep patterns.
- Greater alertness and less daytime sleepiness.
- Less anxiety and depression and better mood.
- Improvements in work productivity.
- Better concentration and memory. Some adults with symptoms of attention deficit hyperactivity disorder have improved after CPAP treatments for apnea. In two studies, however, equal improvements were also observed in people on sham CPAP, suggesting that the actual cognitive benefits from CPAP may be modest.
- Patients' bed partners also report improvement in their own sleep when their mates use CPAP, even though objective sleep tests showed no real difference in the partners' sleep quality.
If patients comply with the CPAP regimen but do not feel less sleepy after a period of time, or their sleep apnea symptoms don't improvement, the airflow pressure may not be high enough. Patients may need to be retested. Likewise, if patients have started using an oral appliance or had a surgical procedure, their doctor problably needs to reevaluate them. Many patients report feeling more alert after CPAP treatments even if objective laboratory tests fail to show significant differences in the number of apneas and wake-up periods.
Side Effects and Getting Used to the Device
CPAP works well for both adults and children, but many patients have problems getting used to the device. Unfortunately, CPAP devices are often cumbersome, which can lead to patients becoming discouraged and stopping treatment. All patients should be warned that the first few nights of CPAP therapy are unnerving. The mask may cause some patients to feel anxious. Starting out with low pressure to get used to the mask may help. Patients may actually sleep less, or have different sleep quality, at the start of treatment.
Nearly all patients complain of at least one side effect. Nearly half of complaints are related to the mask. Many of these problems can be minimized with a well-chosen mask that is comfortable and reduces leakage as much as possible. Thorough education and ongoing support are essential for successful treatment with CPAP.
Common complaints include:
- Irritation in the nose and throat. The most common complaints are nasal congestion and sore or dry mouth, which are caused by leakage that dries the airway. (This may be severe in elderly people or patients who have had uvulopalatopharyngoplasty, a surgical treatment for sleep apnea. Such patients are more likely to stop using CPAP.) Chin straps, nasal salt water sprays, or humidifiers may prevent these side effects. Heated humidification devices are also now available for CPAP users.
- Excessive application of pressure making exhalation difficult.
- A feeling of claustrophobia is a major factor in noncompliance. This can be improved by a lightweight and transparent mask or with masks known as nasal pillows, which are used only around the nostrils.
- Up to 30% of patients have irritation and sores over the bridge of the nose. Getting a properly fitted and cushioned mask can help reduce this problem.
- Eye irritation or conjunctivitis.
- Upper respiratory infections. It is very important to keep the unit clean.
- Patients may also feel temporary chest muscle discomfort, which is caused by an increase in lung volume.
- Severe side effects are very rare but may include heart rhythm disorders (arrhythmias), severe nose bleeding, and air pockets in the skull.
- In addition to initial difficulties with its use, the fixed CPAP needs to be periodically readjusted. Patients can be trained to adjust the CPAP at home, thereby avoiding trips to the sleep professional for machine adjustments and making the process more convenient.
Studies have reported that long-term compliance with CPAP systems is low, with about one-third of patients giving up the treatment. Compliance may be improving, however, probably due to better technologies and better education. Factors that may help include:
- Patient education and support groups
- Adedicated nurse to ensure close follow-up of patients (particularly in the first 2 weeks of therapy)
- Access to doctors to make adjustments as needed have all been shown to greatly improve compliance
(However, sleeping pills do not appear to help patients adapt to the device.) Not surprisingly, patients whose symptoms are noticeably relieved by the procedure early on are more likely to continue the therapy.
Because many patients find CPAP uncomfortable and difficult, they tend not to use it for the duration of the entire night. However, while some patients daytime sleepiness may improve after 4 - 6 hours of CPAP use each night, maximum benefits in quality of life require at least 7.5 hours of nightly CPAP use. It appears that longer nightly duration of CPAP use is best for achieving normal daytime functioning.
Other Related Devices
Bilevel Positive Airway Pressure. Bilevel positive airway pressure (BPAP) systems may be particularly helpful for patients with coexisting lung disease and those with excessive levels of carbon dioxide. These devices have a sensing feature that helps determine and vary the appropriate pressure depending on whether a person is breathing in or out. Greater pressure is needed on inhalation and less on exhalation. These machines are more expensive than the CPAP and may not be covered by insurance.
Autotirtating Positive Airway Pressure Devices. Traditional CPAP devices provide a set pressure based on findings from polysomnography. Autotitrating positive airway pressure (APAP) devices are also available. These devices automatically customize air pressure for the individual patient. For some patients, APAP devices can be used to begin therapy at home without any supervision.
Patients with chronic lung disease, heart failure, obesity hypoventilation syndrome, who do not snore, or who have central sleep apnea syndrome are not considered candidates for APAP.
APAP devices usually use one of three methods:
- Overall pressure is kept low until a specific problem is detected. At that time the pressure is automatically increased rapidly.
- Pressure is low when there are no problems but is raised gradually when they are detected.
- Pressure is gradually raised and lowered in response to problems or their absence. In addition, the device can change depending on problems within single breaths.
APAP devices are more expensive than CPAP devices. However, APAP devices may improve compliance, particularly in patients who have needed high CPAP use. They may be especially helpful for patients who require varying levels of pressure due to other conditions, such as seasonal allergies. They may also be useful as home diagnostic tools for sleep apnea.
Medications
In general, drugs have not been very beneficial except for specific situations. Medications that treat accompanying disorders associated with sleep apnea may be helpful. The following may be helpful for certain patients:
- Modafinil (Provigil), which is also used to treat narcolepsy, was approved by the FDA in 2004 as the first drug to treat the sleepiness associated with obstructive sleep apnea. However, Provigil is meant to be used in combination with -- not as a substitute for -- standard apnea treatments such as CPAP. Sleep experts stress that patients who take Provigil should adhere to CPAP treatment as the drug treats only the symptom of sleepiness, not the underlying health risks associated with sleep apnea. [Modafinil can cause rare, but serious, side effects such as life-threatening rash. For more information on this drug and its side effects, see In-Depth Report #98: Narcolepsy.]
- Thyroid hormone may help sleep apnea in those with low thyroid (hypothyroidism).
Note on Sedatives. Sedatives, narcotics, and anti-anxiety drugs can actually worsen the breathing disturbances and arousal conditions that occur with sleep apnea. These substances cause the soft tissues in the throat to sag and diminish the body's ability to inhale. Apnea sufferers should never use sleeping pills or tranquilizers. Apnea patients undergoing surgery should be sure that their surgeons, anesthesiologists, and other doctors are aware of their sleeping disorder in considering sedatives, anesthetics, and medications taken to relieve pain due to surgery.
Dental Devices
Oral appliances, also called dental appliances or devices, may be an option for patients who cannot tolerate CPAP. The American Academy of Sleep Medicine recommends dental devices for patients with mild-to-moderate obstructive sleep apnea who are not appropriate candidates for CPAP or who have not been helped by it. (CPAP should be used for patients with severe sleep apnea whenever possible.)
Several different dental devices are available. A trained dental professional such as a dentist or orthodontist should fit these devices. Devices include:
- Mandibular advancement device (MAD). This is the most widely used dental device for sleep apnea. It is similar in appearance to a sports mouth guard. MAD forces the lower jaw forward and down slightly, which keeps the airway open.
- Tongue retraining device (TRD). This is a splint that holds the tongue in place to keep the airway as open as possible.
Patients fitted with one of these devices should have a check-up early on to see if it is working; short-term success usually predicts long-term benefits. It may need to be adjusted or replaced periodically.
Benefits of Dental Devices. Dental devices seem to offer the following benefits:
- Significant reduction in apneas for those with mild-to-moderate apnea, particularly if patients sleep either on their backs or stomachs. They do not work as well if patients lie on their side. The devices may also improve airflow for some patients with severe apnea.
- Improvement in sleep in many patients.
- Improvement and reduction in the frequency of snoring and loudness of snoring in most (but not all) patients.
- Higher compliance rates than with CPAP.
Dental devices have shown better long-term control of sleep apnea when compared to uvulopalatopharyngoplasty (UPPP), the standard surgical treatment. There are also few complications with a dental device.
Disadvantages of Dental Devices. Dental devices are not as effective as CPAP therapy. The cost of these devices tends to be high. Side effects associated with dental devices include:
- Nighttime pain, dry lips, tooth discomfort, and excessive salivation. In general, these side effects are mild, although over the long term they cause nearly half of patients to stop using dental devices. Devices made of softer materials may produce fewer side effects.
- Permanent changes in the position of the teeth or jaw have occurred in some cases of long-term use. Patients should have regular visits with a health professional to check the devices and make adjustments.
- In a small percentage of patients, the treatment may worsen apnea. Patients should be monitored with polysomnography (sleep lab evaluation) before and after therapy and when apnea symptoms worsen or recur.
Orthodontal Treatments
An orthodontic treatment called rapid maxillary expansion, in which a screw device is temporarily applied to the upper teeth and tightened regularly, may help patients with sleep apnea and a narrow upper jaw. This nonsurgical procedure helps to reduce nasal pressure and improve breathing.
Surgery
Surgery is sometimes recommended, usually by throat specialists, for severe obstructive sleep apnea. A patient should be sure to seek a second opinion from a specialist in sleep disorders. Few randomized clinical trials, the gold standard of medical research, have been conducted to verify the long-term efficacy of sleep apnea surgery.
Uvulopalatopharyngoplasty (UPPP)
The Procedure. Surgery known as uvulopalatopharyngoplasty (UPPP) removes soft tissue on the back of the throat. Such tissue includes all or part of the uvula (the soft flap of tissue that hangs down at the back of the mouth) and parts of the soft palate and the throat tissue behind it. If tonsils and adenoids are present, they are removed. The surgery typically requires a stay in the hospital.
The Goal of Surgery. The goal of UPPP is threefold:
- Increase the width of the airway at the throat's opening
- Block some of the muscle action in order to improve the ability of the airway to remain open
- Improve the movement and closure of the soft palate
Success Rates. Success rates for sleep apnea surgery are rarely higher than 65% and often deteriorate with time, averaging about 50% or less over the long term. Few studies have been conducted on which patients make the best candidates. Some studies suggest that surgery is best suited for patients with abnormalities in the soft palate who have mild sleep apnea that may or may not involve the tonsils. Results are poor if the problems involve other areas or the full palate. In such cases, CPAP is superior and should always be tried first. Many or most patients with moderate or severe sleep apnea will likely still require CPAP treatment after surgery.
Complications. Uvulopalatopharyngoplasty is among the most painful treatments for sleep apnea, and recovery takes several weeks. It is recommended only for select patients with severe obstructive sleep apnea. The procedure also has a number of potentially serious complications. In fact, in one study, 42% of patients had complaints about the procedure. Some complications include:
- Infection. In one study, this complication was so common that 40% of patients needed another operation because of it. Preventive antibiotics administered an hour before surgery can help reduce this risk.
- Impaired function in the soft palate and muscles of the throat
- Mucus in the throat
- Changes in voice frequency
- Swallowing problems
- Regurgitation of fluids through the nose or mouth
- Impaired sense of smell
- Failure and recurrence of apnea. In such cases, CPAP is often less effective afterward, although one study found that oral appliances (plastic mouth retainer-like devices) may still help.
Experts estimate that in general about 1.6% of patients experience serious complications. Many of these complications can be avoided with proper technique and experienced surgeons. However, a patients health status may also affect outcomes. According to a 2006 study, patients are more likely to experience complications if they have severe sleep apnea, are overweight, have other medical problems, or undergo other surgical procedures at the same time as UPPP.
Laser-Assisted Uvulopalatoplasty (LAUP)
A variation on UPPP called laser-assisted uvulopalatoplasty (LAUP) is being increasingly performed to reduce snoring. It removes less tissue at the back of the throat than UPPP and can be done in a doctor's office. At this time, however, long-term success rates from LAUP are very modest, particularly for reducing apneas. Some doctors, in fact, are concerned that if LAUP eliminates snoring, they may miss a diagnosis of apnea in patients who have the more serious condition.
More than 50% of patients complain of throat dryness after surgery. Throat narrowing and scarring have also been reported. In a minority of patients, snoring becomes worse afterward.
Pillar Palatal Implant
The pillar palatal implant is a noninvasive surgical treatment for mild-to-moderate sleep apnea and snoring. However, the main focus of the procedure is a reduction in snoring. The implant helps reduce the vibration and movement of the soft palate. In this procedure, a doctor inserts 3 short pieces of polyester string into the soft palate. The procedure can be performed in a doctors office and takes about 10 minutes. Unlike uvulopalatopharyngoplasty (UPPP), the pillar procedure requires only local anesthesia. Studies indicate it works as well as UPPP, with less pain and quicker recovery time.
Tracheostomy
Tracheostomy used to be the only treatment for sleep apnea. It is quite straightforward:
- The surgeon makes an opening through the neck into the windpipe and inserts a tube.
- It is almost 100% successful, but it requires a quarter-size opening in the throat. This produces a number of medical and psychological problems associated with recovery.
Today, this operation is performed rarely, usually only if sleep apnea is life-threatening.
Other Procedures
Other surgical procedures may be appropriate to correct facial abnormalities or obstructions that cause sleep apnea. They may be used alone or combined with each other or with UPPP. Most are invasive and reserved for patients with severe sleep apnea who fail to respond to CPAP. They include:
- Genioglossus (tongue advancement), in which an opening is cut where the tongue joins the jawbone and the area is pulled forward.
- Temperature controlled radiofrequency ablation tongue reduction.
- Genioplasty, which is plastic surgery on the chin.
- Hyoid advancement surgery, in which the movable bone underneath the chin is moved forward, pulling the tongue muscle along with it.
- Maxillary or maxillomandibular advancement (MMA), which moves the upper (maxilla) or lower (mandible) jawbone forward. A survey of patients who had MMA found that the surgery changed their facial appearance, but most people thought it was a change for the better.
- Surgery for nasal obstructions (such as a deviated septum) that contribute to snoring and other symptoms.
Removing Adenoids and Tonsils in Children
Adenotonsillectomy, or surgical removal of the tonsils and adenoids, is a first-line treatment for children and adolescents with sleep apnea proven by sleep studies. It cures the condition in 75 - 100% of patients. Two studies, published in 2005, suggested that adenotonsillectomy can significantly improve quality of life for children with obstructive sleep apnea.
Complications include respiratory illness, which occurs in about 25% of children after the surgery. The highest risk for respiratory complications is associated with:
- Age under 3 years old
- Severe sleep apnea
- Heart complications
- Failure to thrive
- Obesity
- Prematurity
- Recent lung infections
- Certain facial structures
- Neuromuscular disease
The procedure may fail to improve apnea in some patients, such as those with very severe disease. Such children are candidates for continuous positive airway pressure (CPAP) therapy.
Removal of the tonsils and adenoids alone is not an effective treatment for adults with sleep apnea, although the procedure may be effective when combined with UPPP surgery.
Resources
- www.sleepapnea.org -- American Sleep Apnea Association
- www.nhlbi.nih.gov -- National Heart, Lung, and Blood Institute
- www.aasmnet.org -- American Academy of Sleep Medicine
- www.sleepfoundation.org -- National Sleep Foundation
- www.nhlbi.nih.gov/about/ncsdr -- National Center on Sleep Disorders Research
- www.sleepeducation.com -- Sleep Education from the American Academy of Sleep Medicine
- www.wfsrsms.org -- World Federation of Sleep Research & Sleep Medicine Societies
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Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
