Continuous positive airway pressure (CPAP) and BiPAP (bilevel) therapy are used to treat sleep apnea. A continuous positive airway pressure (CPAP) machine is the most common and effective treatment, and is often recommended as a treatment option when you are diagnosed with obstructive sleep apnea.
BiPAP may be preferred in more severe cases of sleep apnea or when another diagnosis is present, such as chronic obstructive pulmonary disease (COPD). Both BiPAP therapy and adaptive servo ventilation (ASV) are used to treat central sleep apnea, which occurs when the brain temporarily stops sending signals to the respiratory muscles.
This article explains the differences between CPAP, BiPAP, and ASV and provides information about the different reasons they are used, how BiPAP and CPAP machines work, their cost, and more.
CPAP treatment
The standard treatment for obstructive sleep apnea is to use a machine that provides support to keep your airway open while you sleep. This can be achieved through continuous positive airway pressure (CPAP).
In a CPAP machine, a continuous flow of pressurized room air is provided through a face mask. Portable CPAP machines are also available for travel.
This pressure setting for airflow is often determined by your doctor based on your needs. This can be evaluated as part of a sleep study or can be estimated based on your risk factors, such as your anatomy and weight.
An effective compression setting is intended to prevent apnea and snoring and should reduce the apnea-hypopnea index (AHI) to less than five, as well as improve other symptoms associated with sleep apnea.
A similar type of therapy is AutoCPAP, or APAP, where a set of pressures are provided by the machine. If resistance is detected in the upper airway (at the level of the soft palate or the base of the tongue in the throat), the resulting pressure will self-adjust within the specified range.
BiPAP or bilevel therapy
There is a similar treatment called bilevel, or BiPAP, but it differs in important ways.
The “two-level” component indicates that there are two pressures that the machine can alternate between. This allows you to inhale at a higher pressure and exhale at a slightly lower pressure.
A dual level may be needed when pressures are higher to improve comfort, especially at PAP pressures of 15 centimeters (cm) of water pressure or higher.
BiPAP vs CPAP machine
Aside from the different label or color, from the outside, a BiPAP machine may not look significantly different from a CPAP machine. It still requires the same tubing and face mask used in CPAP therapy. However, it can be more effective in specific circumstances, such as those mentioned above.
Do I need CPAP or BiPAP?
People with the most common form of obstructive sleep apnea usually start treatment with a CPAP or AutoCPAP machine. Bilevel, or BiPAP, is most often used to treat central sleep apnea, which is characterized by cessation of breathing without airway obstruction.
Whether or not you use CPAP or BiPAP for sleep apnea will likely depend on the results of a sleep study.
Central sleep apnea may occur more often in people with heart failure, stroke, or in those who chronically use narcotic pain relievers.
The BiPAP machine may be adjusted to compensate for these breathing pauses by taking additional breaths as needed.
Some devices are so advanced, they alter the airflow delivered to compensate for respiratory and neuromuscular disturbances that also affect breathing. These disorders include chronic obstructive pulmonary disease (COPD), amyotrophic lateral sclerosis (ALS), and other conditions.
Setting options
Unlike CPAP and BiPAP, there are additional device settings that your sleep specialist can request. Many machines, often prefixed with “Auto,” have an automatic feature that allows a range of pressures to be used.
Automatic devices can be of both CPAP or bi-level types. The device is able to respond to minor collapses in the airway and can raise the pressure as needed during the night. This may be helpful if sleep apnea is worsened by changes in sleeping position (such as lying on your back) or by REM sleep causing an increase in events.
There is also a dual-level type that can deliver timed breaths (often called dual-level ST). This can ensure that the minimum number of breaths per minute occurs. This may be important in central sleep apnea.
| Continuous positive airway pressure device | Beep | ASV | |
| very | The most common and effective treatment used for obstructive sleep apnea | It may be used to treat more severe sleep apnea, especially in people with central sleep apnea and/or underlying health problems | It is used to treat people with more complex sleep apnea problems, including central sleep apnea |
| Settings | One setting while breathing | Two settings, one for inhalation and one for exhalation | Monitors breathing and automatically adjusts pressure as needed |
| It costs | $500-$1,500, depending on features | $1000 – $2000 | $2,000 to $3,000 or more |
| insurance | It will likely be covered | It will likely be covered, depending on the diagnosis | It may or may not be covered |
If you’re considering equipment to treat sleep apnea, keep in mind that related items (travel units, flexible tubing, filters) add to costs and may not be covered by your insurance provider.
What is ASV treatment?
Finally, there is another advanced machine called automatic or adaptive servo ventilation (ASV) which has more features to maintain normal breathing during sleep. The volume of air delivered can vary as well as the speed at which the lungs inflate and deflate, among other settings.
These devices are often intended for people who require additional ventilatory support due to systolic heart failure, central sleep apnea, and high altitudes.
When should I switch from CPAP to BiPAP?
Some people switch from CPAP therapy to BIPAP. If changes to your treatment are required, they can be arranged when your healthcare provider sees you for routine follow-up. It is sometimes necessary to arrange a titration study in which different treatment options and settings can be explored in a controlled manner.
A word from Verywell
You don’t have to solve this yourself. Your sleep specialist should be able to correctly determine your treatment needs based on the results of your sleep study and your in-office evaluation. Discuss your options during your visit and stay in close contact if you experience any difficulties treating your sleep apnea.
