For more information, visit http://www.nhlbi.nih.gov/health/health-topics/topics/cpap/

What Is CPAP?

CPAP, or continuous positive airway pressure, is a treatment that uses mild air pressure to keep the airways open. CPAP typically is used by people who have breathing problems, such as sleep apnea.

CPAP also may be used to treat preterm infants whose lungs have not fully developed. For example, doctors may use CPAP to treat infants who have respiratory distress syndrome or bronchopulmonary dysplasia (brong-ko-PULL-mun-ary dis-PLA-ze-ah).

The main focus of this article is CPAP treatment for sleep apnea, although treatment in preterm infants is discussed briefly.

Overview

CPAP treatment involves a CPAP machine, which has three main parts:

A mask or other device that fits over your nose or your nose and mouth. Straps keep the mask in place while you're wearing it.
A tube that connects the mask to the machine's motor.
A motor that blows air into the tube.

Some CPAP machines have other features as well, such as heated humidifiers. CPAP machines are small, lightweight, and fairly quiet. The noise that they make is soft and rhythmic.

CPAP often is the best treatment for obstructive sleep apnea. Sleep apnea is a common disorder that causes pauses in breathing or shallow breaths while you sleep. As a result, not enough air reaches your lungs.

In obstructive sleep apnea, your airway collapses or is blocked during sleep. When you try to breathe, any air that squeezes past the blockage can cause loud snoring. Your snoring may wake other people in the house.

The mild pressure from CPAP can prevent your airway from collapsing or becoming blocked.

The animation below shows how CPAP works to treat sleep apnea. Click the "start" button to play the animation. Written and spoken explanations are provided with each frame. Use the buttons in the lower right corner to pause, restart, or replay the animation, or use the scroll bar below the buttons to move through the frames.

The animation shows how CPAP can help keep the airway open and prevent sleep apnea symptoms.

If your doctor prescribes CPAP, you’ll work with someone from a home equipment provider to select a CPAP machine. (Home equipment providers sometimes are called durable medical equipment, or DME.)

Your doctor will work with you to make sure the settings that he or she prescribes for your CPAP machine are correct. He or she may recommend an overnight sleep study to find the correct settings for you. Your doctor will want to make sure the air pressure from the machine is just enough to keep your airway open while you sleep.

There are many kinds of CPAP machines and masks. Let your doctor know if you're not happy with the type you're using. He or she may suggest switching to a different type that might work better for you.

CPAP also is used to treat preterm infants whose lungs have not fully developed. For this treatment, soft prongs are placed in an infant’s nostrils. The CPAP machine gently blows air into the baby's nose, which helps inflate his or her lungs.

Outlook

CPAP has many benefits. It can:

Keep your airway open while you sleep
Correct snoring so others in your household can sleep
Improve your quality of sleep
Relieve sleep apnea symptoms, such as excessive daytime sleepiness
Decrease or prevent high blood pressure

Many people who use CPAP report feeling better once they begin treatment. They feel more attentive and better able to work during the day. They also report fewer complaints from bed partners about snoring and sleep disruption.

In some preterm infants whose lungs have not fully developed, CPAP improves survival. It also can reduce the need for steroid treatment for the lungs.

Also, in some infants, CPAP prevents the need to insert a breathing tube through the mouth and into the windpipe to deliver air from a ventilator. (A ventilator is a machine that supports breathing.)

CPAP treatment is less invasive than ventilator therapy. Research suggests that CPAP is an appropriate first treatment for some preterm newborns.

Who Needs CPAP?

Your doctor may recommend CPAP if you have obstructive sleep apnea. CPAP often is the best treatment for adults who have this condition.

Children also can have obstructive sleep apnea. The most common treatment for children is surgery to remove the tonsils and adenoids. If symptoms don't improve after surgery, or if the condition is severe, CPAP may be an option.

If you have sleep apnea symptoms, your doctor may recommend an overnight sleep study. A sleep study measures how much and how well you sleep. It also can show whether you have sleep problems and how severe they are. (For more information, go to "What To Expect Before Using CPAP.")

Your doctor will likely refer you to a sleep specialist for the sleep study. Sleep specialists are doctors who diagnose and treat people who have sleep problems.

A special type of CPAP device is used to treat breathing disorders that are similar to sleep apnea, such as chronic hypoventilation or central sleep apnea.

In these conditions, the airways aren't blocked. However, the brain may not send the signals needed for proper breathing. This causes breaths that are too shallow or slow to meet your body's needs.

In central sleep apnea, you may stop breathing for brief periods. This disorder can occur alone or with obstructive sleep apnea. Only a sleep study can find out which type of sleep apnea you have and how severe it is.

In addition to CPAP, there are other positive airway pressure devices. If you don't feel that CPAP is working for you, ask your sleep specialist about other possible options.

Besides treating sleep apnea and other similar disorders, CPAP also is used to treat preterm infants whose lungs have not fully developed. For example, doctors may use CPAP to treat infants who have respiratory distress syndrome or bronchopulmonary dysplasia.

Treatment with CPAP can improve a preterm infant's chance of survival and reduce the need for other treatments and therapies.

What To Expect Before Using CPAP

Before your sleep specialist prescribes CPAP, you'll likely have a sleep study called a polysomnogram (PSG).

You’ll probably stay overnight at a sleep center for a PSG. The study records brain activity, eye movements, heart rate, blood pressure, and other data while you sleep.

What To Expect During a Polysomnogram

Your sleep specialist may suggest a split-night sleep study. During the first half of the night, a technician will check how you sleep without a CPAP machine. This will show whether you have sleep apnea and how severe it is.

If the PSG shows that you have sleep apnea, you might use a CPAP machine during the second half of the split-night study. The technician will help you select a CPAP mask that fits and is comfortable.

While you sleep, the technician will check the amount of oxygen in your blood and whether your airway stays open. He or she will adjust the flow of air through the mask to find the setting that works best for you. This process is called CPAP titration.

Sometimes the CPAP titration study is done on a different night. Your sleep specialist will decide which type of study is best for you and leave instructions with the technician.

What To Expect After a Polysomnogram

Your sleep specialist will review the results from your sleep study. If CPAP will benefit you, he or she will prescribe the type of CPAP machine and the correct settings for you.

Most health insurance companies cover CPAP treatment. You might want to contact your health insurance provider to learn more about your coverage.

Your sleep specialist can refer you to a local home equipment provider. The home equipment provider will use your prescription to set up your CPAP machine. Ask your sleep specialist to recommend a home equipment provider that has a lot of experience with CPAP.

As you adjust to CPAP treatment, continue to work with your sleep specialist. Talk with him or her about how to handle followup questions. Your sleep specialist can answer some questions, but your home equipment provider may need to address others.

Selecting a CPAP Machine and Mask

CPAP units come with many features designed to improve fit and comfort. Your home equipment provider will help you select a machine based on your prescription and the features that meet your needs.

You might be able to use the CPAP unit for a trial period to make sure you're happy with your choice.

There are many types of CPAP masks. The fit of your mask is important, not only for comfort, but also to keep air from leaking out. A mask that fits will help maintain proper air pressure and keep your airway open.

CPAP masks come in many shapes, sizes, and materials. Some fit over your nose and mouth; others cover only your nose. Some masks can be worn with eyeglasses. If you need oxygen, masks are available that have room for an oxygen tube.

You may want to try nasal pillows instead of a mask. Nasal pillows are small, flexible, mushroom-shaped cones that fit into each nostril.

Let your home equipment provider know whether you sleep on your back, side, or stomach. Different types of plastic tubing connect the mask to the CPAP machine. Some types may make it easier for you to sleep on your side or stomach.

What To Expect While Using CPAP

CPAP is a long-term treatment. Many people have questions when they first start using CPAP.

Talk with your sleep specialist about how to handle followup questions. He or she can answer some questions, but your home equipment provider may need to address others. Ask your sleep specialist to recommend a home equipment provider that has a lot of experience with CPAP.

To achieve the full benefits of CPAP, use it every time you sleep—during naps and at night. Most people should use CPAP for at least 7.5 hours each night for the best results.

The CPAP Machine

Adjusting to the CPAP machine can take time. You may feel strange wearing a mask on your face at night or feeling the flow of air. Some people feel confined by the mask. If you feel this way, slowly adjusting to the mask may help.

First, hold the mask up to your face for short periods during the day. Next, try wearing it with the straps for short periods. Then, add the hose.

Breathing with a machine doesn't feel natural. If your machine has a "ramp" feature, you can use it to slowly "ramp up" from a lower air pressure to the pressure that's needed to keep your airways open during sleep. Once you're comfortable using CPAP during the day, try using it at night while you sleep.

Relaxation exercises help some people adjust to using CPAP. Talk with your doctor about whether relaxation exercises might help you.

If you're having trouble adjusting to the mask or the CPAP machine, contact your home equipment provider. Your provider may have staff who can help you adjust to CPAP. Also, you may want to try a different mask that has fewer straps or less contact with your skin.

Followup Care

Your sleep specialist may ask you to schedule a followup visit about a month after you begin using CPAP. He or she will want to see how well you are adjusting to treatment. After that, you may have followup care every 6 or 12 months.

Your sleep specialist might need to adjust the air pressure setting of your CPAP machine if:

You gain or lose a lot of weight
Your symptoms, such as daytime sleepiness, persist or recur
You have another treatment for sleep apnea, such as upper airway surgery or a mouthpiece

Benefits of CPAP

CPAP has many benefits. It can:

Keep your airway open while you sleep
Correct snoring so others in your household can sleep
Improve your quality of sleep
Relieve sleep apnea symptoms, such as excessive daytime sleepiness
Decrease or prevent high blood pressure

With CPAP, you may fall asleep faster and wake fewer times during the night. The pauses in breathing that are typical with sleep apnea won't disrupt your sleep.

Studies also show that treatment with CPAP is linked to a decrease in reported car accidents and near accidents. Some studies have shown that CPAP improves reaction time, concentration, and memory in people who use the treatment.

You may feel better after the first night of using CPAP. You may wake feeling refreshed, alert, and in a better mood. You also may feel less tired during the day.

However, it can take a week to a month to adjust to CPAP. Some people have trouble falling asleep when they first start using CPAP. This problem usually is short term and goes away as you adjust to the treatment.

Even if you don't notice a change right away, stick with the treatment. The benefits are worthwhile. Once you adjust to using CPAP, you'll sleep better.

What Are the Risks of CPAP?

CPAP is a safe, painless treatment. Side effects and other problems usually are minor, and they can be treated or fixed. Talk with your doctor if you're having problems using CPAP. He or she can suggest ways to handle or treat these problems.

Although these problems can be frustrating, stick with the treatment. The benefits of CPAP are worthwhile.

Side Effects

Mask Allergies and Skin Irritation

CPAP masks can cause skin allergies or skin irritation. If this happens, try a different type of mask.

CPAP masks come in many shapes, sizes, and materials. Some have fewer straps and less contact with your face. Some masks may irritate your skin less than others.

If you have trouble finding a mask that works for you, ask your sleep specialist about nasal pillows. These are small, flexible, mushroom-shaped cones that fit into each nostril.

Dry Mouth

Dry mouth can be caused by the CPAP itself or from breathing through your mouth at night. A CPAP machine that has a heated humidifier can help relieve this side effect.

If dry mouth persists, your sleep specialist may suggest a chin strap to keep your mouth closed or a different type of mask.

Talk to your sleep specialist if dry mouth continues. Your mask might be leaking air into your open mouth, causing dry mouth.

Congestion, Runny Nose, Sneezing, Sinusitis, and Nosebleeds

Congestion, runny nose, sneezing, sinusitis (si-nu-SI-tis), and nosebleeds can occur while using CPAP. A CPAP machine that has a heated humidifier can help relieve these side effects. Also, make sure that your CPAP mask fits well.

Some people find that using a saline nasal spray at bedtime prevents these side effects. If these steps don't work, talk to your sleep specialist. He or she may prescribe a steroid nasal spray.

Stomach Bloating and Discomfort

A problem with the air pressure setting on your CPAP machine might cause stomach bloating and discomfort. If you have these side effects, talk to your sleep specialist. He or she may adjust the settings of your machine to relieve these problems.

Problems With the CPAP Equipment

Mask Leaks

Many factors can cause a CPAP mask to leak. To avoid a leak, follow the instructions that come with the mask. Try washing the mask daily. Also, wash your face and use a moisturizer so your skin is moist before you put on the mask.

You might find it helpful to adjust the mask's straps. When straps are too loose or too tight, a leak can happen. You may need to select a different size or type of mask.

If your CPAP mask leaks air, you won’t get the proper amount of air pressure. Also, leaks can lead to skin or eye irritation.

Very small leaks don't stop the machine from producing the correct amount of air pressure. But small leaks can cause a shrill sound that disturbs the sleep of others in the house.

Don't use tape or grease on a mask to prevent leaks, unless advised by your home equipment provider or sleep specialist.

Air Pressure Problems

The air pressure from CPAP makes some people feel like it's hard to exhale (breathe out) or like they're choking or suffocating. Some people swallow air, which may cause burping.

If you have problems with the air pressure from CPAP, it may help to use the "ramp" feature on your CPAP machine. This feature allows the machine to slowly "ramp up" from a lower air pressure to the pressure that's needed to keep your airway open during sleep.

If your machine doesn't have this feature or if it doesn't help, talk to your sleep specialist. He or she may suggest a different CPAP machine. If that doesn't work, your sleep specialist may suggest another type of positive airway pressure.

Mask Removal

To get the full benefit of CPAP, you should use it every time you sleep. Some people remove the CPAP mask while they're asleep. If this happens, you might be able to solve the problem by:

Finding a mask that fits better.
Using a CPAP machine that has a humidifier. This might make the treatment more comfortable and stop you from removing the mask.
Using a chin strap to hold the mask in place.

Some CPAP machines come with an alarm that makes noise if the mask comes off.

Noise

Most new CPAP machines are fairly quiet. The noise that they make is soft and rhythmic. If the noise bothers you, check the air filter to make sure the machine is working properly. Your sleep specialist or home equipment provider also can check the machine for you.

If the CPAP machine is working properly, but the noise still bothers you, try using earplugs or a white-noise sound machine.

Living With CPAP

CPAP is a long-term treatment. To achieve the full benefits of CPAP, use it every time you sleep—during naps and at night. Most people should use CPAP for at least 7.5 hours each night for the best results.

CPAP machines are small, lightweight, and fairly quiet. You can take your machine with you when you travel.

Knowing how to maintain your CPAP machine is important. You also should see your sleep specialist for ongoing care as he or she advises.

Maintaining the CPAP Machine

To properly maintain your CPAP machine, refer to the user manual or ask your home equipment provider how to care for the machine.

Parts of the machine need daily or routine care and cleaning. For example, if your machine has a humidifier, you’ll likely need to clean it daily. You also may need to replace parts of the machine over time.

Your home equipment provider should be able to supply replacement filters, masks, and hoses for your machine.

If you suspect a problem with your CPAP machine, call your home equipment provider. Don't try to fix it yourself.

A small hole in most machines lets out the air that you exhale (breathe out) and keeps the air supply fresh. This isn't a defect in the machine, and you shouldn't try to cover it.

Getting Ongoing Care

Many people have questions when they first start using CPAP. Talk with your sleep specialist about how to handle followup questions. He or she can answer some questions, but your home equipment provider may need to address others.

Ask your sleep specialist to recommend a home equipment provider that has a lot of experience with CPAP. Continue working with your sleep specialist as you adjust to CPAP.

Most CPAP machines record the amount of time you use them on a computer card. Your sleep specialist may ask you to bring the card in to see how well you're doing.

During followup visits, your sleep specialist may need to adjust the air pressure setting of your CPAP machine if:

You gain or lose a lot of weight
Your symptoms, such as daytime sleepiness, persist or recur
You have another treatment for sleep apnea, such as upper airway surgery or a mouthpiece

During followup visits, tell your sleep specialist if you're not happy with your CPAP machine. He or she may suggest switching to a different machine that might work better for you.

Clinical Trials

The National Heart, Lung, and Blood Institute (NHLBI) is strongly committed to supporting research aimed at preventing and treating heart, lung, and blood diseases and conditions and sleep disorders.

NHLBI-supported research has led to many advances in medical knowledge and care. For example, this research has uncovered some of the causes of various sleep disorders and ways to diagnose and treat these conditions.

The NHLBI continues to support research aimed at learning more about sleep disorders and treatments, including CPAP. For example, the NHLBI currently sponsors research to find out whether behavioral therapy programs can help people stick with their CPAP treatment.

The NHLBI also supports research that explores the factors that affect sleep, how a lack of sleep increases certain health risks, and new ways to diagnose and treat sleep disorders. For example, the Sleep Heart Health Study explores the links between sleep apnea and heart conditions and stroke.

Much of this research depends on the willingness of volunteers to take part in clinical trials. Clinical trials test new ways to prevent, diagnose, or treat various diseases and conditions.

For example, new treatments for a disease or condition (such as medicines, medical devices, surgeries, or procedures) are tested in volunteers who have the illness. Testing shows whether a treatment is safe and effective in humans before it is made available for widespread use.

By taking part in a clinical trial, you can gain access to new treatments before they’re widely available. You also will have the support of a team of health care providers, who will likely monitor your health closely. Even if you don’t directly benefit from the results of a clinical trial, the information gathered can help others and add to scientific knowledge.

If you volunteer for a clinical trial, the research will be explained to you in detail. You’ll learn about treatments and tests you may receive, and the benefits and risks they may pose. You’ll also be given a chance to ask questions about the research. This process is called informed consent.

If you agree to take part in the trial, you’ll be asked to sign an informed consent form. This form is not a contract. You have the right to withdraw from a study at any time, for any reason. Also, you have the right to learn about new risks or findings that emerge during the trial.

For more information about clinical trials related to sleep apnea or CPAP, talk with your doctor. You also can visit the following Web sites to learn more about clinical research and to search for clinical trials:

For more information about clinical trials for children, visit the NHLBI’s Children and Clinical Studies Web page.

Links to Other Information About CPAP

NHLBI Resources

Bronchopulmonary Dysplasia (Health Topics)
National Center on Sleep Disorders Research
Respiratory Distress Syndrome (Health Topics)
Sleep Apnea (Health Topics)
Sleep Studies (Health Topics)
"Your Guide to Healthy Sleep"

Non-NHLBI Resources

Nasal CPAP (MedlinePlus)

Clinical Trials

Children and Clinical Studies
Clinical Trials (Health Topics)
Current Research (ClinicalTrials.gov)
NHLBI Clinical Trials
NIH Clinical Research Trials and You (National Institutes of Health)
ResearchMatch (funded by the National Institutes of Health)
Sleep Heart Health Study (supported by the NHLBI)