CPAP vs APAP vs BPAP, What is the Difference?

By | March 28, 2016

What Are The Differences Between CPAP, APAP and BPAP Machines?

If you’ve been looking through my website, you’ve probably noticed I use the acronym CPAP throughout it. Today, more and more, the acronyms APAP and BPAP (or BIPAP) are also being used. But what do these acronyms mean and what is the difference between the three of them?

The term CPAP, as I’ve mentioned, stands for Continuous Positive Airway Pressure. When patients are diagnosed with Obstructive Sleep Apnea (OSA), the most common way to treat sleep apnea has been to use Continuous Positive Airway Pressure (CPAP). However, CPAP machines can only be set to a single pressure.

What’s the Difference between APAP and CPAP?

The term APAP stands for Auto Positive Airway Pressure. Many patients today cannot use a CPAP machine. For example, based on the results of a sleep study, a sleep specialist may write a prescription such that the machine is set to an optimal pressure and that’s what pressure the machine will provide, all of the time, no matter what. The goal of a sleep study is to make sure that the machine delivers enough air pressure to hold the airway open when the patient is most vulnerable (ie. sleeping on their back which is when they have the most apnea sessions). The problem is that this state normally only occurs 25% of the night, so three-quarters of the night CPAP users may be getting a lot higher pressure than they really need. For this reason, many people are now getting a prescription for an APAP machine. Rather than having a machine set at one continuous pressure, APAPs are set to disperse air at a range of pressures, constantly adjusting to the minimum pressure needed to keep a person’s airways open throughout the night. The breath-by-breath adjustments tend to maximize comfort and people are therefore more apt to use APAP therapy for years down the road.

Changes in Insurance for CPAP and APAP 

It used to be that a person would have to “fail” at CPAP treatment before their insurance company would approve the upgrade to APAP, but over time sleep specialists have been prescribing APAP treatment, even though it costs a little more than CPAP treatment.  The bottom line appears to be this, if you’ve been diagnosed with Obstructive Sleep Apnea and your insurance company approves Positive Airway Pressure (PAP) treatment for you, they don’t care anymore if it’s CPAP or APAP treatment, just as long as you are getting treatment for your sleep apnea. A CPAP prescription can now be used to buy an APAP machine.

What’s the Difference between BIPAP and CPAP?

BiPAP (also referred to as BPAP) stands for Bilevel Positive Airway Pressure. It is very similar in function and design to a CPAP machine. Similar to a CPAP machine, A BiPAP machine is a form of therapy for people who suffer from sleep apnea. Both types of machines deliver pressurized air through a mask to a person’s airways. The air pressure keeps the throat muscles from collapsing, allowing a person to breathe easily and regularly throughout the night. The main difference between BIPAP and CPAP is that a BiPAP machine blows air at two distinct pressures: one at inhalation and another at exhalation. The dual settings allow a person to get more air in and out of their lungs. It should be noted that BiPAPs require a specific prescription from your sleep specialist.

As I mentioned above, a CPAP machine can only be set to a single pressure that remains consistent throughout the night. However, many CPAP machines have a feature that starts off with a lower pressure setting and gradually builds to the prescribed pressure. This comfort feature simply makes the pressure at the beginning more tolerable and less immediate, once the pressure builds to the required setting, it stays at that setting for the rest of the night. This is one of the complaints about CPAP devices in that some people find the constant singular pressure difficult to exhale against. For people who have higher pressure strengths, exhaling against the incoming air can seem difficult, as if they’re having to force their breathing out.

BiPAP machines can also be set to include a breath timing feature that measures the amount of breaths per minute a person should be taking. If the time between breaths exceeds the set limit, the machine can force the person to breath by temporarily increasing the air pressure.

Who Might Benefit from BiPAP Therapy?

  • BiPAP machines are often prescribed to people with sleep apnea who have higher pressure settings or low oxygen levels
  • BiPAP machines are often used after CPAP treatment has failed to adequately treat certain people
  • BiPAP machines can be helpful for people who have cardiopulmonary disorders such as congestive heart failure
  • They are often prescribed to people with lung disorders or certain neuromuscular disorders

The bottom line is there is not much difference in the overall outcome between these three types of machines.

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6 thoughts on “CPAP vs APAP vs BPAP, What is the Difference?

  1. Zailinah

    Hey Shawn,

    Firstly, thank you for this clear and informative article. I saw a TV program the other day that discussed sleep apnea and the use of machines and masks to manage the condition. I can only empathize with people who have this condition, particularly those who don’t have the condition diagnosed and treated. It could be brushed aside as just part and parcel of one’s sleeping pattern?

    Your explanation on the differnt types of machines here is very clear and I can bet that it will help those who are looking for effective treatment on sleep apnea. To me, it’s always better to be informed before you speak to a doctor as that way, at least you have a better understanding of the machines, their various functions .

    I take that you are making progress with your sleep apnea treatment and hopefully going back to sleep in the same room as ot your half:)

    1. Shawn

      Hi Zailinah,
      Thank you very much for your comments! My wife is glad that I’ve been finally diagnosed and able to wear a CPAP mask. She couldn’t handle the snoring and the fact that I would stop breathing so many times in an hour was probably a little nerve-wracking!!! I found it interesting that there were different types of machines for different circumstances as well. I was originally using a CPAP machine but now I have an APAP machine. All I know is that I feel well rested in the morning and my wife is so happy that I can be in the same room without the snoring!!!

  2. Carl radke

    Hey Shawn, I know a lot more about sleep apnea than I did before reading your post. Very informative and we’ll written. Much success , Carl

    1. Shawn

      Thank you for the feedback Carl! I’m glad that you found the information on my site useful.
      Best regards,

  3. Rich Far

    Hi Shawn,
    I do not suffer from this condition however found your article very interesting and concise.
    You certainly research, understand and present your material in a way that makes it evident you desire to help others’ all you can who are unfortunate enough to have sleep apnea.

    I like discovering sites like yours so when I do come across someone who may have indications of sleep apnea I can direct them to a possible source of aid.

    Thank you Shawn and keep up the good work.

    Blessings Be –

    – Rich

    1. Shawn

      Hello Rich!
      Thank you very much for your comments. The topic of sleep apnea is a very important one to me so it was very easy for me to create this website. I hope that the information on it is of use to anyone who thinks they may have a sleeping disorder of some type and can get the treatment that they need.
      I would be most grateful if you recommended my site to anyone you know who might benefit from it.
      All the best,


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