CPAP Therapy

CPAP vs. BiPAP Differences: How to Know if You Need a BiPAP Machine

Do you think you need a BiPAP machine? BiPAP, or “BiLevel,” machines are very different from CPAP and APAP machines. In this article, we’ll share the pros and cons of each as well as what makes them different, and why you may benefit from one over the other. 

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The Differences Between CPAP, APAP, and BiPAP MachinesCPAP Machine Types Infographic
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What’s a CPAP Machine?

CPAP is an acronym that stands for “Continuous Positive Airway Pressure,” and is used to treat Obstructive Sleep Apnea (OSA). The continuous supply of pressurized air from the CPAP machine applies enough pressure to keep your airways open while you sleep.

As a result, you can achieve the uninterrupted breathing needed for quality sleep. CPAP machines supply pressurized air at one specific pressure, and can’t change pressures automatically like an APAP machine can.

Who is it good for? CPAP machines are good for anyone who has been on the same pressure for many years, and who hasn’t needed a lot of adjustments over time.

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What’s an APAP Machine?

The key difference between CPAP and APAP is important when considering your breathing needs: an APAP machine can automatically adjust to whatever pressure is right for you, while CPAP machines cannot. Many people report that using an APAP machine improves their comfort level because of the automatic pressure adjustments.

Who is it good for? APAP machines are intended for anyone who needs frequent pressure adjustments or people who may be active sleepers, as they may need multiple adjustments during the night.

Related Reading: BiPAP Machine vs. APAP Machine: Differences and Uses of Both

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What’s a BiPAP Machine?

BiPAP, or BiLevel, devices use two different pressures, a higher pressure for inhalation and a lower pressure for exhalation. It’s important to point out that while this is often more comfortable, BiPAP machines aren’t simply a “better APAP machine.” BiLevel machines are oftentimes are used to treat conditions such as Central Sleep Apnea or Complex Sleep Apnea because of the machine’s unique ability to prompt breathing.

CPAP machines and APAP machines have their own pressure reduction systems built-in, often called “exhale relief” or “pressure relief.” It’s not the same as a BiPAP, but it’s a system designed to improve overall user comfort.

Ultimately, it’s your physician’s decision whether or not you’d need a BiPAP, and it’s important to remember it’s only for a specific medical purpose.

Who is BiPAP for? BiPAP is for anyone who suffers from Central Sleep Apnea, Complex Sleep Apnea, Congestive Heart Failure, or COPD, among other conditions. It can be used to treat Obstructive Sleep Apnea, but there are far less expensive options available if that’s the only reason you’d prefer a BiLevel therapy device.

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What’s the difference between CPAP and BiPAP?

There is one major difference between CPAP and BiPAP machines. CPAP machines are set at one single pressure, while BiPAP machines are programmed with two distinct pressures, one for inhaling and one for exhaling. CPAP machines are primarily used to treat Obstructive Sleep Apnea, while BiPAP machines are used to treat Central Sleep Apnea, Complex Sleep Apnea, or COPD.

Here are a few other key differences between the machines:

  • There is no ultra-portable BiPAP machine, while there are travel CPAPs
  • Unlike CPAP’s, BiPAP machines can deliver pressure settings up to a setting of 25.
  • BiPAP machines may be more comfortable because of the two different pressures.

Also, sensors in the BiPAP machine detect an increase in airflow as you inhale and immediately add to this inhaled airflow, increasing its volume. When you breathe out, sensors indicate that airflow has stopped and it reduces the amount of air pressure applied to the airway. As a result of this change in airflow, breathing becomes easier.

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What is BiPAP Therapy? How Does It Work?

The key thing that makes a BiPAP different from other PAP therapy devices is its use of two distinct pressures: IPAP and EPAP. IPAP stands for “inspiratory positive airway pressure” (the set pressure for inhaling). EPAP stands for “expiratory positive airway pressure,” or the set pressure for exhaling.

When you breathe in, IPAP kicks in and delivers a higher pressure for you when you’re inhaling, and when you breathe out, EPAP activates and delivers a lower pressure as you exhale, so you’re not fighting against the incoming air.

What’s the Process for Starting BiPAP Therapy?

The process for getting started with a BiLevel device is similar to how you’d get started with a CPAP machine. Here are the steps you would typically follow to start BiPAP therapy:

  1. Make an appointment with a Sleep Specialist.
  2. At the appointment, the Sleep Specialist will examine your airway and likely prescribe a Sleep Study.
  3. Sleep Studies can either be done in a lab or at home. Most people will be able to do the test at home. However, if there’s something else going on, like restless leg syndrome, you may need to do your test in a sleep lab.
  4. Once the results of the test come back, your physician will determine the right treatment plan for you. If you have Complex Sleep Apnea or Central Sleep Apnea, you may be prescribed a BiPAP machine. If you’re diagnosed with Obstructive Sleep Apnea, you’ll most likely be prescribed a CPAP or APAP machine.
  5. From there, you’ll take your prescription for a PAP therapy device and either purchase a PAP machine on your own, from a company like, for a lower price; or you can go through your insurance and possibly pay more as well as deal with compliance restrictions.

Related Reading: CPAP Machine Cost & Insurance: Everything You Need to Know 

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BiPAP Mask vs. CPAP Mask: What’s the Difference?

There’s actually no such thing as a BiPAP mask. Any mask that works for a CPAP machine or an APAP machine will work for a BiPAP machine. While it is true that BiLevel machines work differently from CPAP and APAP machines, there’s no change in the type of masks you can choose from. The best mask for your therapy depends on your preference.

To find the best mask for your therapy, you’ll need to determine your favorite sleeping position and note how you breathe while you’re asleep, you’ll also need to know your pressure setting (be sure to check your prescription for that). For instance, if your usual pressure is above 20, you will want to focus on masks that create a heavy-duty seal. If your normal pressure is below 20, you can use any mask that will work for you.

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Why Would a BiPAP Machine be a Good Fit for Me?

Although most people with sleep apnea use CPAP, there are certain conditions where BiPAP might be a better option:

If you require higher CPAP pressures. If you have low oxygen levels and your sleep specialist has determined that you require higher CPAP air pressure to treat your apnea effectively, you may benefit from a BiPAP machine. Many people who need higher air pressure prefer the comfort of a BiPAP, with its lower expiratory pressure. Exhaling against a high air pressure can feel like a struggle and may make it harder for you to fall asleep or stay asleep.

If you have Central Sleep Apnea or Complex Sleep Apnea. These conditions require your therapy device be able to prompt you to breathe in case you stop breathing, which the BiPAP machine can do (and no other type of machine can). This is the primary reason why you would need one.

If you have obesity hypoventilation syndrome (OHS). This form of sleep-disorder breathing tends to affect people who have a high BMI. You may breathe too shallowly or slowly during sleep, which can lead to respiratory depression (hypoventilation) and a high level of carbon dioxide (CO2) in your bloodstream.

A dangerous condition called hypoxia can develop, sometimes resulting in heart failure or respiratory failure. BiPAP, with its restrictive component, can be a better option for people with OHS because of its ventilatory effect. The higher inspiratory pressure and the lower expiratory pressure can help you to get sufficient oxygen while expelling CO2.

If you have COPD/Overlap Syndrome. If you have both sleep apnea and chronic obstructive pulmonary disease (COPD), you may have what’s termed “overlap syndrome.” When you have COPD, you don’t have a correct gas exchange of CO2 and oxygen in your bloodstream when you’re awake, and your body never gets a chance to correct this imbalance when you’re asleep.

With COPD and sleep apnea, your breathing problems can last around the clock, leading to a number of potentially serious health complications. However, by using a BiPAP, you may be able to improve your breathing when you’re asleep. With its higher inspiratory pressure and lower expiratory pressure, BiPAP can help rebalance the blood oxygen and CO2 levels while you sleep.

Whether you’d benefit more from BiPAP or CPAP is a decision your doctor will make based on your sleep test results and current medical condition. If you have questions about BiPAP and CPAP therapy, ask your sleep medicine physician. It’s important that you understand the specific benefits of the sleep apnea therapy that your doctor recommends for you.

Related Reading: Best BiPAP Machines Reviewed

Is BiPAP Better Than CPAP?

When it comes to treating your sleep apnea with BiPAP vs. CPAP, it’s not a question of whether or not one is “better” than the other because they treat different things.

PAP therapy depends on what your needs are. CPAP may be right for you if your pressure hasn’t changed much over the years. And BiPAP may be the best treatment option for if you need a higher pressure or have other conditions.

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Next Steps

BiPAP therapy may not be right for everyone; however, for those that need it, it can be a valuable tool to help get back on track to a healthier life. If you think you may benefit from a BiPAP machine reach out to your doctor today.


  1. Ian van Straaten Reply

    I am very active in sport gym, cycling and power walk. I have suffered with sleep and sleep apnea for a while which has increased my blood pressure during my interrupted sleep evenings. I need to take blood pressure tablets as a result of this.. and causes me not to have a continuous sleep experience. Can you suggest and approach for me? Some this that is compact yet functional.

    • Hey Ian,

      Lots of CPAP users are very active in sports. I am sorry to hear that you are having to deal with high blood pressure and interrupted sleep. I would suggest to you that the most economical option would be a small travel machine and a mask. Another option that you may consider is Provent Therapy. Either way you will need to speak with your doctor because we will require a prescription. If you would like assistance selecting a machine and mask that would best suit your needs we will be happy to assist you if you give us a call at 1-800-356-5221. Here is a link to the Provent Therapy that I mentioned

      Whichever option you select please remember that we will require a prescription. We are happy to assist you in obtaining a prescription, just give us a call.

  2. Dave Wardell Reply

    In your article, you don’t say what the letters ST in BiPAP-ST means. I understand that type of machine initiates a breathe for the user, but I’d like to know what ST means.

    BTW the machine I’m using now has an APAP mode and also adjustable exhalation relief in both APAP and CPAP mode. I swear my machine, which is not a BiPAP-ST, can initiate a breath on its own. It doesn’t say it has that capability in the user manual. But I think the manufacturer has incorporated the feature without documenting it in the manual. To give the user the best possible experience. This maybe to avoid lawsuits from the legal owners of the ST technology.

  3. Eileen A Sedilko Reply

    Interesting. I wish I’d seen this before I saw my dr. last week. I wonder if I need a Bipap instead of Cpap.

  4. I have a Dreamstation Auto BiPap with settings at 9/13. I had a ruptured brain aneurysm and subarachnoid hemorrhage/stroke in February and they put me on a BiPap machine while I was in the hospital. In the past 2 weeks my AHI has doubled or more from readings of 2 to 4 to 9.3 to 17.6. I don’t know why or what to do about it.

    • Hi Mary, I would encourage you to speak with your doctor, as they can view your therapy data and make a determination as to if you require a setting adjustment, or what may be causing the increase in your AHI’s.

      If you would like to speak with us further, please feel free to contact us at: 1-800-356-5221.

      We wish you the best!

  5. I am having differculty @ nite sleeping , a lot of moving in my sleep , sleepy during day , taking naps , I stop breathing even though I am using a c-pap machine, please help me the doc keep saying that my sleep reports look ok , I need help

    • Hey Rachel, i’m sorry to hear about the troubles with your CPAP therapy. How long have you been using your CPAP machine? The symptoms you are referring to sounds like your therapy isn’t working for you. You may want to suggest to your doctor to increase/adjust your pressure setting.

      Also, what type of mask are you using? Have you checked your leak rate? One of the most important factors with successful CPAP therapy, is having a comfortable mask. If you aren’t using a full face mask, you may try switching to one and if you’re currently using a full face mask, you may want to try a different one.

      Please be sure to continue speaking with your doctor about the difficulties you are experiencing with your therapy.

      Also, please feel free to reach us at: 1-800-356-5221, for further assistance.

      Best Wishes!

  6. Hi, If one has complex Apnea, a mix of Central and Obstructive Apnea, can he use a Bipap Biflex without the ST? Without back up rate?

    • Hi Ricardo, yes you can use a BiPap without the ST. Really, this is something you must speak with your doctor about. The type of machine you get will totally depend on the prescription your doctor writes for you based upon the results from your sleep study.

      For further questions, or concerns, please feel free to reach us at: 1-800-356-5221, or e-mail us at:

      Have a great day!

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