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The Complete Guide to Using CPAP with Oxygen

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Millions of men and women suffer from Sleep Apnea, and that means they may be at greater risk for serious medical issues, like heart attacks, strokes, obesity, depression and even accidents caused by too little sleep. CPAP machines can offer an excellent solution for many of these problems, providing a steady stream of air that helps keep airways open and unobstructed during sleep.

But sometimes, CPAP alone may not be enough to treat an underlying medical condition or to prevent an existing condition from becoming worse. Often, these patients benefit from the addition of supplemental oxygen that’s delivered through their CPAP machine.

Interestingly, many Sleep Apnea patients – even those who have been using CPAP – are surprised to learn that CPAP is not the same as oxygen therapy. Since both CPAP therapy and supplemental oxygen deliver therapy air through masks, it’s easy to see how that confusion happens.

But if your doctor has suggested using CPAP with oxygen, if you have an underlying medical condition like heart or lung disease, or if you think oxygen might benefit your CPAP results, it’s important to know what makes CPAP machines different than oxygen, so you can make sure you’re getting the best therapy for your needs.

Is CPAP considered oxygen?

No. CPAP machines use a continual stream of air – the same mixture of oxygen, nitrogen and other elements in the air we normally breathe – to keep your airways open while you sleep. During CPAP therapy, a special mask delivers the stream of air directly to your airway to help prevent the soft tissues at the back of your throat from collapsing.

It’s these intermittent periods of collapse that interfere with normal breathing, producing the interruptions in breathing that are the hallmark of Sleep Apnea.

While CPAP delivers “normal” air, oxygen therapy focuses only on the delivery of pure oxygen. Patients with certain types of health problems, including Sleep Apnea, other breathing disorders, and heart disease, often benefit from added oxygen to provide cells and organs with the enriched air they need to improve the way they function.

Like CPAP, oxygen is delivered through a mask. Oxygen can be stored in a pressurized tank or, more frequently, it can be taken directly from the surrounding air using a concentrator. The concentrator uses filters to remove other elements and impurities from the air, so only pure oxygen is delivered.

What is the difference between CPAP and oxygen?

In addition to the “type” of air each therapy delivers, CPAP and oxygen therapy can be used to treat different types of disorders and diseases.


CPAP, or continuous positive airway pressure, is a therapy that was developed specifically to treat Sleep Apnea (sometimes called Obstructive Sleep Apnea or OSA). CPAP works by providing a gentle and continuous stream or “force” or air to your airway while you sleep. As this gently pressurized air passes through your airway, it helps to keep the airway open – particularly the airway at the back of your throat.

In people with Sleep Apnea, these soft tissues “over-relax” during sleep, dropping down into the airway and temporarily blocking normal breathing. The flow of air provides just enough pressure to help keep the soft tissues “in place,” so the airway remains open, and you can breathe normally.


Oxygen therapy delivers only pure oxygen, and it’s typically used to treat patients who have specific medical conditions that result in low oxygen levels in the blood, including people with:

  • congestive heart failure
  • emphysema
  • lung cancer or other lung diseases
  • chronic obstructive pulmonary disease (COPD)
  • other conditions (like Sleep Apnea) that cause low levels of circulating oxygen during sleep

Your cells and organs depend on a certain level of oxygen to function. Supplemental oxygen can provide additional oxygen when your breathing is hampered by a disease or medical condition like Sleep Apnea.

Can you use oxygen with CPAP?

Yes. Many patients benefit from adding oxygen to CPAP. Your doctor will be able to determine if CPAP with oxygen could be beneficial for you based on your medical history and other factors.

How to connect oxygen to a CPAP machine

If you use a CPAP device, adding oxygen to CPAP therapy is a relatively simple process. Both the CPAP airstream and the oxygen come in through the same mask. Depending on the oxygen delivery system you have, you may need to use an adapter (with or without an additional one-way valve) to connect the oxygen supply line with the tubing used by your CPAP device, or your mask may have a special adapter built into its design.

Be sure to read and follow the directions provided with your oxygen supply unit, or call CPAP.com at 1-800-356-5221 and ask a member of our team for assistance.

There are other precautions you need to follow when using oxygen with CPAP. For instance, you should not smoke around an oxygen supply device, and you should also keep your device away from heat. Most units also instruct you not to turn the CPAP device off while oxygen is in use. In most cases:

  • you should not turn the oxygen unit on until the CPAP unit is already running; and,
  • you should turn the oxygen unit off before you turn off the CPAP machine.

Your oxygen system will provide you with specific instructions for your unit.

My CPAP unit has a humidifier. Can I still use oxygen?

Yes, CPAP units that have humidifiers built in to moisturize the air can still use supplemental oxygen. The oxygen unit will be connected in the same manner, using the guidelines provided by your oxygen device manufacturer.

Can I use a BiPAP machine with oxygen?

Yes, you can use a BiPAP machine with oxygen. As when using oxygen with CPAP, the oxygen will come in through the same mask you use for your BiPAP therapy. You may need a separate adapter to connect the tubing of both devices, or your mask may have a built-in adapter. Your oxygen unit will provide you with complete instructions for hooking the oxygen up to your BiPAP device.

Can you use oxygen to treat Sleep Apnea?

Some studies have shown that oxygen alone can be beneficial for patients with Sleep Apnea, while other patients may not need additional oxygen to gain the benefits from CPAP. As a standalone treatment, oxygen delivery typically is not enough to keep the airway at the back of the throat open. This means that even though oxygen is flowing through a mask or cannula, you’ll still experience breathing interruptions – and much of the oxygen will wind up not being inhaled.

CPAP uses a more forceful (but still gentle) stream of air that “triggers” the muscles at the back of the throat to remain more “taut,” preventing the soft tissue from dropping into the throat and “cutting off” air.

Benefits of adding oxygen to CPAP

When the airway “collapses” during a Sleep Apnea event, you aren’t able to breathe in air as you usually do while awake. That means your organs – particularly your heart and brain – and other tissues aren’t receiving the average levels of oxygen they need to stay healthy and work the way they should.

Over time, the breathing interruptions and lower levels of oxygen associated with Sleep Apnea can contribute to serious medical problems, including heart disease and cardiovascular events like heart attacks. When you use CPAP with oxygen, you reap two main benefits:

  • The CPAP device and delivery system help keep your airway open for normal breathing while you sleep, and they also allow you to breathe in more of the supplemental oxygen.
  • The supplemental oxygen provides your body with the extra oxygen it needs to function normally.

Not everyone who has Sleep Apnea will need supplemental oxygen. Your doctor will be able to determine if adding oxygen to CPAP makes sense for you and your medical needs.

Learn more about using CPAP with oxygen.

If you’d like to find out more about combining CPAP with oxygen therapy, or if you’d like more information about CPAP units, masks or supplies, if you have insurance questions, or if you just want to learn more about CPAP and its benefits, we can help. Check out our blog and sign up for our newsletter for up-to-date information about CPAP and Sleep Apnea, and to receive special offers and discounts on equipment and supplies.

  • David Repasky

    David Repasky has been using CPAP treatment since 2017 and has first-hand experience with what it's like to live with Sleep Apnea. He brings the patient's perspective to the CPAP.com blog and has received formal training in CPAP machines, masks, and equipment.

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32 Responses

      1. While it is true that it is technically not flammable it does strongly support combustion; I have had patients with severe facial burns from smoking while using oxygen

    1. Hey Watson, we would be glad to assist you with reducing the pressure on your machine. The instructions depends on the machine that you have, so please contact us with your machine near you. Also, please be sure to speak with your doctor to confirm that they recommend your pressure be reduced. We can be reached at 1-800-356-5221 for assistance.

      We look forward to hearing from you soon.

  1. My c pap machine is always haveing water backing up in the mask at night what can i do to fix this problem

    1. Hi Carolyn, i’m sorry to hear that you are getting water in your mask. This is common issue while using CPAP Therapy called, Rainout. Please see the link below, which will explain Rainout in more detail and provide you with some possible solutions to reduce the water in the hose.


      If you have any further questions, or concerns please reach us at: 1-800-356-5221, or you can e-mail us at: cpap@cpap.com.

      Enjoy your day!

  2. Hey Carolyn. My CPAP hose was also backing up water and into the mask. Was advised by my CPAP provider that the humidity setting was too high at 5 & to reduce to a lower setting until the hose no longer retained moisture. Lowered mine to 3 & problem solved. Easy fix.

  3. while wearing my oxgen concentrator mask pumping oxygen through my nostrils can i wear my bipap mask over that while using the bipap machine?

  4. I use AirSense10 and Invacare O2 concentrator. From CPAP there is a oneway valve and then a T to connect oxygen concentrator. I am bleeding in 2lpm oxygen. I have three questions:
    1. Why do I have to turn on CPAP before O2?
    2. Why do I have to turn off O2 before CPAP
    3. What will be the impact if I increase 2lpm to 4 lpm. Pressure out of CPAP is set at 13cm of water in my case, the O2 at 2 lpm is almost insignificant.

    1. Hi Yogesh, you asked some very good questions. The reasoning for questions one and two is basically, for safety reasons. Oxygen, is a combustible and there are electrical components that are triggered when it is turned on and off.

      In reference to question three, please speak with your doctor regarding setting changes to your Oxygen and the medical impact that it will have on you.

      I hope this information helps. Please feel free to reach us at: 1-800-356-5221, or you may e-mail us at: cpap@cpap.com.

      Have a great day!

  5. My wife has used a cpap for several years; this year she has been placed on supplemental oxygen, and it connects to the cpap through an adapter.
    But now we’ve added a humidifier bottle to the oxygen concentrator so that the oxygen is humidified. Since the cpap is humidified and the oxygen is humidified, is that a problem? should we run one or the other dry?

    Thanks for any assistance!

    1. Hi Paul, my apologies for the delayed response. I have confirmed that your wife should be able to use both the Oxygen humidification and the CPAP humidifier in conjunction with one another. This should not cause a problem as the moisture from the Oxygen, will not be integrated to your CPAP Therapy.

      Please feel free to reach us at: 1-800-356-5221 with any further questions, or concerns.

      Have a great day!

  6. Hi ya’ll. I was diagnosed in 2014 with severe OSA and asthma. They thought COPD at first. My last sleep study results showed 133 times a minute I stopped breathing and did not reach stages 2 and 3 or it would have been much higher. Previous study was 153 events/hour. With O2 at 2 LPM and CPAP at constant 15 setting, it is manageable. If I nap, my O2 drops below 80% often if I wear my wrist O2 alarm set to go off at 80% to warn me. I may wear it if I want to check how I’m doing. I drift off in my chair without warning and should go to my room and wear my CPAP and O2 per my pulmonologist.

    My question is what about having a window open at night since it’s nice and cool here in AR. Could my son have his window open or any other windows if my O2/CPAP are running? I have to have a fan on in my room even with O2. I was raised sleeping with my windows open, even in winter at times as my mom really cranked up our wood stove. I’ve never smoked, done drugs or anything. Parents smoked heavily and with wood heat and Mom had COPD and CHF.

    I never knew about the order of on/off of my equipment, so thanks so much for all your great info.

    1. Hi Sandra, I haven’t located any information which states you are not able to open your window while using your CPAP machine and Oxygen. Just to be certain, you should confirm with your medical provider, if opening your windows is safe while you are receiving Oxygen and CPAP Therapy.

      I’m sorry I couldn’t provide a for certain answer, but if you have any other questions, or concerns, please feel free to reach us at: 1-800-356-5221.

      Enjoy your day!

  7. Hi, my name is Diana and I am interested in information about the cap machine and face mask, I have sleep apnea and I also have pulmonary hypertension. I am interested in using a cannula mask, I can stand anything in my face, it gives me claustrophobia. Can anyone help with any kind of information please.

    1. Hey Diana, yes! We will be more than happy to assist you in selecting a mask that may be a good match for you. In order for us to provide you with efficient service we need to ask you some additional questions. Please give us a call at: 1-800-356-5221.

      We hope to hear from you soon!

  8. I am currently on 2 L of oxygen a day and I was wondering since I’ve never been on oxygen for and I’m now getting ready to get a CPAP machine if I would be able to wean off oxygen because we don’t know why my oxygen levels are dropping when I take it off and get up and do stuff but if I sit still he stays in the 90s

    1. Hey Gord, if you have a machine that records your advanced therapy data, it will tell you the amount of leakage you have for your CPAP therapy, but not your Oxygen. I am not aware of a way to determine what the leak rate is for Oxygen, except if you use your CPAP machine, without Oxygen, get the leak rate and compare it to the leak rate while using the Oxygen.

      Please do not stop your CPAP therapy, or Oxygen unless your doctor instructs you to do so.

      For further questions, or concerns, please reach us at: 1-800-356-5221.

      We wish you the best!

  9. I have COPD and sleep apnea and currently using a AirSense 10 with a continuous flow oxygen concentrator. When traveling can I use a smaller more portable pulse dose concentrator with my current CPAP machine or does it require a continuous flow concentrator?

    1. Hi Sammy, your AirSense 10 machine, can certainly be used with a portable pulse dose concentrator. Please keep in mind that your doctor, should make the decision on if a pulse dose concentrator, would be ideal for you. It really depends on what type of concentrator your prescription is for.

      Please see the link below for details on a concentrator we stock which allows both continuous flow and pulse dose.


      Also, below I have linked the flow rate setting options, so that you may speak with your doctor to see if your prescription match with the available setting capabilities.


      For further questions, or concerns, please feel free to reach us at: 1-800-356-5221, or you may e-mail us at: cpap@cpap.com.

      Have a great day!

  10. I suffer from central apneas. My sleeping habits are horrible and I am lucky to average 3.5 hours of sleep a night over a week. I am considering adding oxygen therapy as it seems that I sleep better at a lower altitude. It seems like the only explanation for this would be oxygen levels. I guess my question is, do you know anything about central apnea and if so, do you think this is a wise choice for me to look into.

    1. Hi Aileen, i’m sorry to hear you haven’t been able to get much sleep. Whereas, you may very well benefit from Oxygen therapy, this would ultimately be a decision made by your doctor. Yes, I think it would be wise for you to speak with your doctor to see if Oxygen use would be medically beneficial to you.

      For further questions, or concerns, please reach us at: 1-800-356-5221, or you may e-mail us at: cpap@cpap.com.

      Best Wishes!

  11. your site aays the followin turn on cpap then concetrator and the nturn off concetratot then cpapvthere are many other reliable sites that say cpap on then concentrator to turrn off cpap first than o2 im geting so confused and also i have my machine in my vedroom areain a very small aprtment there is 10 inches freed space all the way around and alot more feet in the back- next to the machine 10 inches away is my dresser i have perfumes on them is that ok? along with 1-Feet away is my dogs kennel and i sometimes during the day not noght when machine is on spray disinfetant around kennel is that ok- and i sleep on a blowup camping air mattress the tubing is behind the bed with 7 inches space and the cpap unti is on the other side of bed plugged int oan entirely different outlet and circuit- is that ok– can these repsonse be sent to my email thanks

    1. Hello, as stated in the article, in most cases you will need to turn the Oxygen on after the CPAP is running and Oxygen off, before you turn off your CPAP machine. The article also states your concentrator, should have included instructions for the process that should be followed for your concentrator.

      Also, what is the name/manufacturer of your concentrator? In order for us to properly answer your questions, this is information that we would need. Keep in mind that the manufacturer of your concentrator, should be able to provide you guidance regarding questions on the distance required for your dog and perfumes to be away from your concentrator and all other concerns can be addressed as well.

      For further concerns, or follow up responses you may e-mail us at: cpap@cpap.com, or contact us at: 1-800-356-5221.

      Have a great day!

  12. I have recently started on a sleep apnea machine. My question is does the machine feed oxygen when I breath in or out?

    1. Hi Barbara,
      The CPAP machine, doesn’t feed Oxygen when you breath in/out. If you need Oxygen, you can bleed Oxygen in with your CPAP therapy, if you have an Oxygen Concentrator.

      For further questions, or concerns, please feel free to reach us at: 1-800-356-5221, or you may email us at:

      Have a great day!

      Best Wishes!

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