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Bilevel Positive Airway Pressure (BiPAP)

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Bilevel positive airway pressure (BiPAP) is a breathing treatment for sleep apnea and other health conditions that impact breathing. This treatment is less common than continuous positive airway pressure (CPAP). However, in some situations, it is more beneficial.

Bilevel positive airway pressure (BiPAP)

For example, where CPAP provides consistent air pressure, BiPAP offers varying pressure. BiPAP's difference in air pressure can be helpful for people who have trouble exhaling against CPAP's continuous pressure.

This article explains how BiPAP is used to treat obstructive sleep apnea and central sleep apnea.

Man sleeping with BiPAP mask on his face
Getty Images

What Is BiPAP or Bilevel Therapy?

Much of a BiPAP machine is the same as the standard CPAP machine. For example, it still requires a face mask and tubing connected to the device. But there are some differences between BiPAP and CPAP.

The pressurized air settings of the BiPAP include:

  • Inspiratory positive airway pressure (IPAP): This is the pressure the machine provides as you inhale. The BiPAP provides a higher IPAP than the CPAP. So, when you inhale, the BiPAP supports your breath as you take it in.
  • Expiratory positive airway pressure (EPAP): This is the pressure the machine provides when you exhale. The BiPAP offers a lower pressure that allows you to breathe out comfortably.

These pressures are preset based on your doctor's prescription. They alternate just like your breathing pattern.

Beyond these standard settings, there are a few other available variations. They include:

When BiPAP Therapy Is Used

BiPAP is breathing support that treats central sleep apnea. The cause of this condition is now always known, but it is sometimes seen in people who have:

  • Neurological disorders like Parkinson's disease and multiple system atrophy
  • Opioid use
  • Congestive heart failure
  • Prior stroke

Doctors may also prescribe it in more severe obstructive sleep apnea. BiPAP is beneficial when mixed apnea events are present, suggesting a component of central sleep apnea.


BiPAP is more expensive than a standard CPAP machine. It may be two or three times the cost of a CPAP. The ASV models can cost more than $4,000.

In addition to treating central sleep apnea, BiPAP is also helpful in the following situations:

  • People who have trouble with CPAP: People who have difficulty breathing out against CPAP pressure may benefit from BiPAP. People more commonly have problems with CPAP when higher pressures are required to keep the airway open. For example, at pressures higher than 15 centimeters of water pressure (CWP), BiPAP may help to improve compliance among those struggling with CPAP therapy.
  • People who are hospitalized: BiPAP is a non-invasive treatment for people who are in respiratory distress but who do not wish to be on a ventilator.
  • People with neuromuscular disease: It may be helpful in those with conditions that cause nerve and muscle weakness, such as amyotrophic lateral sclerosis (ALS).


BiPAP is most often used to treat central sleep apnea. But, doctors may also prescribe it when someone does not tolerate CPAP well and when someone needs breathing support but doesn't want to be on a ventilator.

BiPAP, Bilevel, and VPAP

There is some confusion about the word BiPAP, bilevel, and VPAP. They are all essentially the same thing. However, the names of the device vary somewhat based on the manufacturer. They include:

  • Respironics: One of the major manufacturers of these devices, Respironics, has registered BiPAP as a trademark name for the technology generically called bilevel.
  • ResMed: The other major competitor, ResMed, calls similar devices VPAP (variable positive airway pressure).
  • AirCurve: ResMed also markets AirCurve that is a bilevel device. 

Though the names may be different, the basic principles are the same.


In most cases of obstructive sleep apnea, CPAP alone is sufficient as a therapy. However, BiPAP may be a good alternative in the more complicated scenarios or when it is difficult to tolerate CPAP.

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