What Is Central Sleep Apnea?

Central sleep apnea is a disorder in which your breathing repeatedly stops and starts during sleep due to lack of respiratory effort. Unlike obstructive sleep apnea, in which you can't breathe normally because of upper airway obstruction, central sleep apnea occurs when your brain doesn't send proper signals to the muscles that control your breathing. Central sleep apnea is less common, accounting for less than 5 percent of sleep apneas.
Central sleep apnea may occur as a result of other conditions, such as heart failure and stroke. Sleeping at a high altitude also may cause central sleep apnea.
Treatments for central sleep apnea may involve using a device to keep your upper airway open or using supplemental oxygen.
SYMPTOMS :
Observed episodes of stopped breathing or abnormal breathing patterns during sleep
Abrupt awakenings accompanied by shortness of breath
Shortness of breath that's relieved by sitting up
Difficulty staying asleep (insomnia)
Excessive daytime sleepiness (hypersomnia)
Difficulty concentrating
Snoring
Although snoring indicates some degree of increased obstruction to airflow, snoring may also be heard in the presence of central sleep apnea. However, snoring may not be as prominent with central sleep apnea as it is with obstructive sleep apnea.
WHEN TO SEE A DOCTOR :
Consult a medical professional if you experience, or if your partner observes, any signs or symptoms of central sleep apnea, particularly the following:
Shortness of breath that awakens you from sleep
Intermittent pauses in your breathing during sleep
Difficulty staying asleep
Excessive daytime drowsiness, which may cause you to fall asleep while you're working, watching television or even driving
Ask your doctor about any sleep problem that leaves you chronically fatigued, sleepy and irritable. Excessive daytime drowsiness (hypersomnia) may be due to other disorders, such as narcolepsy or obstructive sleep apnea.
CAUSES :
Central sleep apnea occurs when your brain fails to transmit signals to your breathing muscles. Central sleep apnea can be caused by a number of conditions that affect the ability of your brainstem — which links your brain to your spinal cord and controls many functions such as heart rate and breathing — to control your breathing. The cause varies with the type of central sleep apnea you have. Types include:
Idiopathic central sleep apnea. The cause of this uncommon type of central sleep apnea isn't known. It results in repeated pauses in breathing effort and airflow.
Cheyne-Stokes respiration. This type of central sleep apnea is most commonly associated with congestive heart failure or stroke, and it is characterized by a rhythmic, gradual increase and then decrease in breathing effort and airflow. During the weakest breathing effort, a total lack of airflow (central apneas) can occur.
Medical condition induced apnea. In addition to congestive heart failure and stroke, several medical conditions may give rise to central apneas. Any damage to the part of the brain that controls breathing (the brainstem) may impair the normal breathing process.
High-altitude periodic breathing. Periodic breathing occurs in most people if they're exposed to a high-enough altitude, such as an altitude greater than 15,000 feet (4,572 meters). The change in barometric pressure at this altitude can cause loss of breath as well as rapid breathing (hyperventilation). The breathing pattern can be similar to Cheyne-Stokes respiration.
Drug or substance induced apnea. Taking certain medications such as opioids — for example, morphine, oxycodone or codeine — may cause your breathing to become irregular, to increase and decrease in a regular pattern, or to stop completely.
RISK FACTORS :
Certain factors put you at increased risk of central sleep apnea:
Being male. Males are more likely to develop central sleep apnea than are females.
Heart disorders. People with atrial fibrillation or congestive heart failure are more at risk of central sleep apnea. Central sleep apnea may be present in between 30 and 40 percent of people with congestive heart failure.
Stroke or brain tumor. These conditions can impair the brain's ability to regulate breathing.
High altitude. Sleeping at an altitude higher than you're accustomed to may increase your risk of sleep apnea. Altitudes above 15,000 feet (4,572 meters) can temporarily cause the condition in most people. High altitude sleep apnea is no longer a problem when you return to a lower altitude.
Taking opioids. Opioids, such as morphine, oxycodone and codeine, increase the risk of central sleep apnea.
COMPLICATIONS :
Central sleep apnea is a serious medical condition. Complications include:
Cardiovascular problems. Sudden drops in blood oxygen levels that occur during sleep apnea increase blood pressure and strain the cardiovascular system. These changes raise the risk of heart failure and stroke. If there's underlying heart disease, these repeated multiple episodes of low blood oxygen (hypoxia or hypoxemia) worsen prognosis and increase the risk of abnormal heart rhythms.
Daytime fatigue. In addition, the repeated awakenings associated with sleep apnea make normal, restorative sleep impossible. People with sleep apnea often experience severe daytime drowsiness, fatigue and irritability. You may have difficulty concentrating and find yourself falling asleep at work, while watching TV or even when driving.
TESTS AND DIAGNOSIS :
Your doctor may make an evaluation based on your signs and symptoms or may refer you to a sleep disorder center. There, a sleep specialist can help you decide on your need for further evaluation. Such an evaluation often involves overnight monitoring of your breathing and other body functions during sleep. Tests to detect central sleep apnea may include:
Nighttime monitoring (nocturnal polysomnography). During this test, equipment monitors your heart, lung and brain activity, breathing patterns, arm and leg movements, and blood oxygen levels while you sleep. This can help your doctor rule out other conditions — such as periodic limb movements or narcolepsy — that can cause excessive daytime sleepiness but require different treatment.
Blood oxygen monitoring (oximetry). This screening method involves using a small device that monitors and records your blood oxygen level while you're asleep. A small sleeve fits painlessly over one of your fingers to collect the information overnight at home. If you have sleep apnea, the results of this test will often show drops in your oxygen level during apneas and subsequent rises with awakenings. If the results are abnormal, your doctor may have you undergo polysomnography to confirm the diagnosis. Oximetry doesn't detect all cases of sleep apnea, so your doctor may still recommend a polysomnogram even if the oximetry results are normal.
TREATMENT :
Treatments for central sleep apnea may include:
Treatment for associated medical problems. Possible causes of central sleep apnea include other disorders, and treating those conditions may help your sleep apnea. For example, appropriate therapy for heart failure may eliminate central sleep apnea.
Reduction of opioid medications. If opioid medications are causing your sleep apnea, your doctor may gradually reduce your dose of those medications.
Supplemental oxygen. Using supplemental oxygen while you sleep may help if you have central sleep apnea. Various forms of oxygen are available as well as different devices to deliver oxygen to your lungs. This treatment generally isn't recommended for those with heart failure.
Medications. Certain medications have been used to stimulate breathing in people with central sleep apnea. For example, some doctors prescribe acetazolamide to prevent central sleep apnea in high altitude.
Continuous positive airway pressure (CPAP). This method, also used to treat obstructive sleep apnea, involves wearing a mask over your nose while you sleep. The mask is attached to a small pump that supplies pressurized air which holds open your upper airway. CPAP may prevent the airway closure that can trigger central sleep apnea. As with obstructive sleep apnea, it's important that you use the device only as directed. If your mask is uncomfortable or the pressure feels too strong, talk with your doctor so that adjustments can be made.
Bilevel positive airway pressure (bilevel PAP). Unlike CPAP, which supplies steady, constant pressure to your upper airway as you breathe in and out, bilevel PAP builds to a higher pressure when you inhale and decreases to a lower pressure when you exhale. The goal of this treatment is to boost the weak breathing pattern of central sleep apnea. Some bilevel PAP devices can be set to automatically deliver a breath if the device detects you haven't taken a breath after a certain number of seconds.
Adaptive servo-ventilation (ASV). This newer airflow device is designed to treat central sleep apnea and complex sleep apnea. The device monitors your normal breathing pattern and stores the information in a built-in computer. After you fall asleep, the machine uses pressure to regulate your breathing pattern and prevent pauses in your breathing.

What Is Obstructive Sleep Apnea?

Obstructive sleep apnea is a potentially serious sleep disorder in which breathing repeatedly stops and starts during sleep. Several types of sleep apnea exist, but the most common type is obstructive sleep apnea, which occurs when your throat muscles intermittently relax and block your airway during sleep. The most noticeable sign of obstructive sleep apnea is snoring, although not everyone who has obstructive sleep apnea snores.
Anyone can develop obstructive sleep apnea, although it most commonly affects older adults. It's also especially common in people who are overweight. Obstructive sleep apnea treatment may involve using a device to keep your airway open or undergoing a procedure to remove tissue from your nose, mouth or throat.
SIGNS and SYMPTOMS of Obstructive Sleep Apnea include:
Excessive daytime sleepiness (hypersomnia)
Loud snoring
Observed episodes of breathing cessation during sleep
Abrupt awakenings accompanied by shortness of breath
Awakening with a dry mouth or sore throat
Morning headache
Frequent urination at night
Difficulty staying asleep (insomnia)
WHEN TO SEE A DOCTOR :
Consult a medical professional if you experience, or if your partner observes, the following:
Snoring loud enough to disturb your sleep or that of others
Shortness of breath that awakens you from sleep
Intermittent pauses in your breathing during sleep
Excessive daytime drowsiness, which may cause you to fall asleep while you're working, watching television or even driving a vehicle
Many people don't think of snoring as a sign of something potentially serious, and not everyone who has sleep apnea snores. But be sure to talk to your doctor if you experience loud snoring, especially snoring that's punctuated by periods of silence. With sleep apnea, snoring typically is loudest when you sleep on your back, and it quiets when you turn on your side.
Ask your doctor about any sleep problem that leaves you chronically fatigued, sleepy and irritable. Excessive daytime drowsiness (hypersomnia) may be due to other disorders, such as narcolepsy.
CAUSES :
Obstructive sleep apnea occurs when the muscles in the back of your throat relax too much to allow normal breathing. These muscles support structures including the soft palate, the uvula — a triangular piece of tissue hanging from the soft palate, the tonsils and the tongue.
When the muscles relax, your airway narrows or closes as you breathe in and breathing may be inadequate for 10 to 20 seconds. This may lower the level of oxygen in your blood. Your brain senses this inability to breathe and briefly rouses you from sleep so that you can reopen your airway. This awakening is usually so brief that you don't remember it.
You can awaken with a transient shortness of breath that corrects itself quickly, within one or two deep breaths, although this sequence is rare. You may make a snorting, choking or gasping sound. This pattern can repeat itself five to 30 times or more each hour, all night long. These disruptions impair your ability to reach the desired deep, restful phases of sleep, and you'll probably feel sleepy during your waking hours.
People with obstructive sleep apnea may not be aware that their sleep was interrupted. In fact, many people with this type of sleep apnea think they sleep well all night.
RISK FACTORS :
Anyone can develop obstructive sleep apnea. However, certain factors put you at increased risk:
Excess weight. More than half of those with obstructive sleep apnea are overweight. Fat deposits around your upper airway may obstruct your breathing. However, not everyone who has sleep apnea is overweight and vice versa. Thin people can develop the disorder, too.
Neck circumference. The size of your neck may indicate whether or not you have an increased risk of obstructive sleep apnea. That's because a thick neck may narrow the airway and may be an indication of excess weight. A neck circumference greater than 17 inches (43 centimeters) for men and 15 inches (38 centimeters) for women is associated with an increased risk of obstructive sleep apnea.
High blood pressure (hypertension). Obstructive sleep apnea is relatively common in people with hypertension.
A narrowed airway. You may inherit a naturally narrow throat. Or your tonsils or adenoids may become enlarged, which can block your airway.
Chronic nasal congestion. Obstructive sleep apnea occurs twice as often in those who have consistent nasal congestion at night, regardless of the cause. This may be due to narrowed airways.
Diabetes. Obstructive sleep apnea is three times more common in people who have diabetes.
Being male. In general, men are twice as likely to have sleep apnea.
Being black, Hispanic or a Pacific Islander. Among people under age 35, obstructive sleep apnea is more common in blacks, Hispanics and Pacific Islanders.
Being older. Sleep apnea occurs two to three times more often in adults older than 65.
Menopause. A woman's risk appears to increase after menopause.
A family history of sleep apnea. If you have family members with sleep apnea, you may be at increased risk.
Use of alcohol, sedatives or tranquilizers. These substances relax the muscles in your throat.
Smoking. Smokers are nearly three times more likely to have obstructive sleep apnea.
Sleep apnea is considered a serious medical condition. Complications may include:
COMPLICATIONS :
Cardiovascular problems. Sudden drops in blood oxygen levels that occur during sleep apnea increase blood pressure and strain the cardiovascular system. About half the people with sleep apnea develop high blood pressure (hypertension), which raises the risk of heart failure and stroke. The more severe the obstructive sleep apnea, the greater the risk of high blood pressure. Patients with sleep apnea are much more likely to develop abnormal heart rhythms such as atrial fibrillation. If there's underlying heart disease, these repeated multiple episodes of low blood oxygen (hypoxia or hypoxemia) can lead to sudden death from a cardiac event.
Daytime fatigue. The repeated awakenings associated with sleep apnea make normal, restorative sleep impossible. People with sleep apnea often experience severe daytime drowsiness, fatigue and irritability. They may have difficulty concentrating and find themselves falling asleep at work, while watching TV or even when driving. Children and young people with sleep apnea may do poorly in school, have reduced mental development or have behavior problems. Treatment of sleep apnea can improve these symptoms, restoring alertness and improving quality of life.
Complications with medications and surgery. Obstructive sleep apnea also is a concern with certain medications and general anesthesia. People with sleep apnea may be more likely to experience complications after major surgery because they're prone to breathing problems, especially when sedated and lying on their backs. Before you have surgery, tell your doctor that you have sleep apnea. Undiagnosed sleep apnea is especially risky in this situation.
Sleep-deprived partners. Loud snoring can keep those around you from getting good rest and eventually disrupt your relationships. It's not uncommon for a partner to choose to sleep in another room. Many bed partners of people who snore are sleep deprived as well.
People with obstructive sleep apnea may also complain of memory problems, morning headaches, mood swings or feelings of depression, and a need to urinate frequently at night (nocturia).
TESTS AND DIAGNOSIS :
Your doctor may make an evaluation based on your signs and symptoms or may refer you to a sleep disorder center. There, a sleep specialist can help you decide on your need for further evaluation. Such an evaluation often involves overnight monitoring of your breathing and other body functions during sleep. Tests to detect sleep apnea may include:
Nocturnal polysomnography. During this test, you're hooked up to equipment that monitors your heart, lung and brain activity, breathing patterns, arm and leg movements, and blood oxygen levels while you sleep.
Oximetry. This screening method involves using a small machine that monitors and records the oxygen level in your blood while you're asleep. A simple sleeve fits painlessly over one of your fingers to collect the information overnight at home. If you have sleep apnea, the results of this test will show drops in your oxygen level during apneas and subsequent rises with awakenings. If the results are abnormal, your doctor may have you undergo polysomnography to confirm the diagnosis. Oximetry doesn't detect all cases of sleep apnea, so your doctor may still recommend a polysomnogram even if the oximetry results are normal.
For milder cases of sleep apnea, your doctor may recommend lifestyle changes such as losing weight or quitting smoking. If these measures don't improve your signs and symptoms or if your apnea is moderate to severe, a number of other treatments are available. Certain devices can help open up a blocked airway. In other cases, surgery may be necessary.
TREATMENT :
Treatments for obstructive sleep apnea may include:
Continuous positive airway pressure (CPAP). If you have moderate to severe sleep apnea, you may benefit from a machine that delivers air pressure through a mask placed over your nose while you sleep. With CPAP (SEE-pap), the air pressure is somewhat greater than that of the surrounding air, and is just enough to keep your upper airway passages open, preventing apnea and snoring.
Although CPAP is a preferred method of treating sleep apnea, some people find it cumbersome or uncomfortable. With some practice, most people learn to adjust the tension of the straps to obtain a comfortable and secure fit. You may need to try more than one type of mask to find one that's comfortable. Some people benefit from also using a humidifier along with their CPAP system.
Don't just stop using the CPAP machine if you experience problems. Check with your doctor to see what modifications can be made to make you more comfortable. Additionally, contact your doctor if you are still snoring despite treatment or begin snoring again. If your weight changes, the pressure settings may need to be adjusted.