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SomnoSure Education Center

What is a BiPAP Machine? CPAP vs BiPAP

Posted by Theresa Shumard on Dec 3, 2015 10:00:00 AM

 bipap machine

This factoid is worth mentioning for political correctness or historical purposes. “BiPAP” is a technically a misnomer for one treatment for sleep apnea. It is a commonly used ter
m in the sleep disorders arena, however BiPAP is actually a proprietary name for one manufacturer’s machine. It is actually one of the first companies to build them, and it remains one of the largest manufacturers today. 


Let’s liken this to another scenario for a moment. Think of “Kleenex” tissues when you have a cold. Many of us generically refer to those as just “kleenex,” although that is a registered name brand. The Kleenex Company was one of the first to manufacture tissues, thus they became popularly known by the proprietary name for most consumers. These are officially called Kleenex® Brand Tissues. The same situation exists for BiPAP.  It was/is just easier for people to say or remember.

BiPAP stands for Bilevel Positive Airway Pressure, and since everyone else is doing it <wink>, I shall use the term throughout this blog entry. Just to give you another helping of “alphabet soup” in your sleep disorders “diet” today, I will also mention that Bilevel Positive Airway Pressure is also sometimes referred to as BPAP, Bi-PAP, Bi PAP, VPAP or Bilevel PAP. Okay. I will behave now with all the acronyms...


Physiology of the Untreated Upper Airway - Awake and Asleeposa_upper airway_throat

The Bi-PAP functions similarly and looks like a continuous positive airway pressure (CPAP) machine. Akin to a CPAP unit, a Bi-PAP unit is a non-invasive therapy. Via a CPAP mask, positive airway pressure creates a pneumatic or “invisible” splint that keeps the upper airway open or inflated during sleep.

The basic upper airway physiology of the upper airway while awake and while asleep for those with untreated sleep apnea should always be considered before any patient ever puts the mask and machine on. When we are awake, we know we are to keep breathing, thus naturally keeping our upper airways open. When we fall asleep, muscles and tissue in the body relax. Relaxed tissue can fall over the opening to interrupt the breathing – sleep apnea. This is where the splint from PAP comes in. It keeps the upper airway unobstructed and allows free breathing and oxygenation of our organs. This is even if the relaxation of slumbered muscles has occurred, as is the case with sleep apnea.


What are the Differences? Bilevel PAP and CPAP

When the first commercially available CPAP machines were prescribed for patients, it was a huge boon for patients across the globe. Please don’t tell anyone, but I am old enough to remember this event :-)  In a blog in the near future, we will discuss the history of how these came into the market in the last century, and the phenomena that followed. For now, let’s talk about the differences between CPAP and its cousin, Bilevel PAP.

Typically, CPAP machines are the first line of defense in treating sleep apnea. The pressure that is delivered is constant and remains at one level as it holds open the upper airway. The amount of continuous pressure needed is determined by a sleep study and prescribed by a physician.


Exhalation Relief from Bilevel PAP

I can remember several patients I cared for in the sleep lab saying something very profound that made me really ponder what they were experiencing with CPAP. Some people do not tolerate one continuous pressure. This can be especially difficult upon exhalation particularly when their pressure is set to a higher therapeutic level.

“I feel like I am hanging my head out the car window, trying to exhale as the vehicle is traveling 90 miles an hour!” several patients said.  

Bi-PAP units are set with a higher pressure for the times the person is inhaling, and a lower pressure is set for exhaling. The acronyms for these settings are called IPAP and EPAP, respectively, “I” standing for inspiratory (inspiration or inhalation) and “E” for expiratory (exhalation). The machine senses the differences between the person inhaling vs exhaling and functions accordingly.

Now imagine how surprised I was when Bilevel PAP was first sold commercially and magazine advertisements for it depicted a man with his head hanging out of a moving car. I guess my patients weren’t the only ones that felt this way. Maybe they told someone at a sleep apnea support group meeting and the idea just caught on...

BPAP machines can also be setup with a feature that measures the amount of breaths per minute a person is supposed to be taking. If the time between breaths exceeds the set limit, the machine can initiate breathing by briefly increasing the pressure.

Benefits of BPAP

BPAP machines are often prescribed to sleep apnea patients with high pressure settings or low oxygen levels, and are often used after CPAP has failed to be tolerated. People with lung disorders, some neuromuscular disorders, and cardiopulmonary disorders (for instance, congestive heart failure) may also benefit from BiPAP.


Patient Education and Compliance to Therapy

After you have a sleep study, your physician will know whether you need a CPAP or a Bilevel PAP. It is always a good idea for patients to educate themselves about their available options. Should a person feel uncomfortable with any treatment, I would urge them to have a discussion with their physician or sleep testing staff. The last thing anyone wants is for you to put the CPAP machine in the closet and not use it due to non-compliant feelings. Depending on insurance coverage, a BPAP unit just might be the right option.


If you are having difficulty tolerating CPAP, feel free to call us at our SomnoSure headquarters in St Louis at (314) 842-2884. Also, you can download our free eBook below which describes the differences in CPAP, APAP, and Bilevel Positive Airway Pressure machines.


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Topics: cpap, sleep apnea, bipap