What Is BiPAP Therapy?

Bilevel positive airway pressure (BiPAP), also sometimes referred to as BPAP, is a mechanical breathing device with a mask that is used to treat sleep apnea and other health conditions that impair breathing. This includes certain cases of COVID-19 in which BiPAP may be used to delay mechanical ventilation.

BiPAP is a less common alternative to continuous positive airway pressure (CPAP) but, in some situations, may be more beneficial. For example, where CPAP provides consistent air pressure, BiPAP offers varying pressure during inhalations and exhalations. This 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.

What BiPAP Does

A BiPAP machine is used when you can breathe on your own, but require some help pushing air into your lungs so you maintain healthy oxygen levels. It is used in medical settings, as well as at home.

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.

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

• Bilevel ST: This includes the timed delivery of a breath if the machine detects a pause in your breathing. These pauses often occur in central sleep apnea.
• Auto or adaptive servo-ventilation (ASV): These advanced settings vary the timing, length, and volume of the breaths the machine delivers. 

When BiPAP Therapy Is Used

BiPAP is a form of breathing support that treats central sleep apnea (CSA). CSA occurs when the brain doesn't send proper signals to the muscles that control breathing, causing prolonged gaps n breathing.

The cause of CSA is not always known but is sometimes seen in people who have:

• Neurological disorders like Parkinson's disease and multiple system atrophy
• Sleep-disordered breathing due to opioid drug use
• Congestive heart failure (CHF)
• Prior stroke

Doctors may also prescribe it for severe cases of obstructive sleep apnea (OSA). This is the more common type of sleep apnea that occurs when your upper airway gets partially or completely blocked.

As opposed to CSA which is neurologic (related to the brain), OSA is caused by a mechanical problem that blocks the airways, including chronic obstructive pulmonary disease (COPD) and pulmonary edema.

BiPAP is beneficial when there is mixed sleep apnea, meaning that there are components of both CSA and OSA.

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. This is especially true for people who require higher pressure—typically higher than 15 centimeters of water pressure (CWP)—to keep the airway open.
• People who are hospitalized: BiPAP is a non-invasive treatment for people who are in respiratory distress but who need to be on a mechanical ventilator. This may be the case for people with respiratory complications of COVID-19.
• 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 vs. Bilevel vs. VPAP

There is some confusion about the word BiPAP, bilevel, biphasic, BPAP, and VPAP (variable positive airway pressure). 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.
• AirCurve: ResMed also markets AirCurve which is a bilevel device. 

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

Summary

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.

A Word From Verywell

BiPAP is an alternative to CPAP to treat those with central sleep apnea. In addition, those who cannot tolerate CPAP and those hospitalized with respiratory distress who do not wish to be on a ventilator may opt for BiPAP.

If you wonder whether BiPAP would be appropriate for you, start by speaking with your sleep doctor. After they evaluate your risk factors and sleep study, they can recommend the proper treatment.