CPAP vs. APAP vs. BiPAP: Which One Is Best For Sleep Apnea?

Positive airway pressure (PAP) machines are the mainstay of treating obstructive sleep apnea. Over the years, with the development of different PAP models with different features, it’s getting more and more confusing to differentiate all these machine from one another, especially since various manufacturers use different names for certain models and comfort features.

As a summary, CPAP stands for continuous positive airway pressure. These machines blow a constant level of positive air pressure through a mask into your nose (or nose and mouth). Bilevel PAP refers to a machine that delivers two different levels, where a higher pressure is used during inhalation and a much lower pressure is given during exhalation. BiPAP is actually a registered brand name from Respironics. Auto-titrating PAP machines adjust your pressures as needed. There are other variations such as auto-bilevel devices and ASV units which are used for complex or central sleep apnea. For this discussion we’ll talk about CPAP, Bilevel and auto-titrating units only.

With so many different models to choose from, people continue to ask me which is the best option. If your insurance company pays for your PAP machine, you don’t have a choice—you have to start with a basic CPAP machine. Most people do well with standard CPAP models, but there will always be people who don’t do well. But before switching to a new machine, you have to first go through the standard trouble-shooting steps to make sure that there’s no leak, mouth breathing, humidity issues, mask fit, etc. It’s also important to use machines that give more objective feedback such as your AHI and leak rates, rather than just the total number of hours used. Some people then end up trying an autoPAP machine and do great, whereas for others, it makes no difference. Sometimes, continuous pressure from a CPAP machine works better than an autoPAP machine. Others do better with bilevel models.

If you look at all the published reports comparing CPAP vs. autoPAP vs. BiPAP machines, there are some differences in terms of compliance, leak rates, or tolerability, but overall, there’s no significant difference between the three in terms of subjective sleepiness, AHI measures, or quality of life scores. This is why some sleep doctors state that essentially, there’s no difference in the overall outcome between these three types of machines.

However, since research studies lump together everyone, including responders and nonresponders, it’s not a true representation of real-life outcomes. There will always be some patients that do better on autoPAP compared to a CPAP machine. Others do better on CPAP than autoPAP. Some others do much better on bilevel devices. So based on evidence based medicine, decisions are being made to downplay the potential advantages of various PAP models. I think that this is not good clinical practice. You should start with the basics first, but for patients that are frustrated and not tolerating PAP therapy, it’s worthwhile to consider other PAP options. In most cases, there are a lot of simple steps that can be taken to fully optimize the patient’s current CPAP machine, but you should never discount other options.

The same argument can be made for oral appliances and for surgery. A significant number of people do well with these options, if done properly. Unfortunately, most people who are given CPAP fall through the cracks, and are never given the opportunity to truly benefit from therapy. This is why the long-term compliance rate is so low for CPAP.

Ultimately, it’s not which model or which form of therapy is better, but start with the CPAP basics and do everything possible make sure that you’re using it properly. If it doesn’t work, talk with you doctor to discuss other PAP options. If PAP therapy doesn’t work, then consider non-PAP options.

If you’re a PAP user, did you try different models? If so, which one works best for you?

Please note: I reserve the right to delete comments that are offensive or off-topic.

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14 thoughts on “CPAP vs. APAP vs. BiPAP: Which One Is Best For Sleep Apnea?

  1. I started out with a cpap, but when I read about apap I wanted to try it… I have been using it for quite awhile and I just KNOW cpap was the better choice for me… I still feel tired a lot of the time and am wondering if I should go back to cpap… it worked so much better for me! I’m just afraid insurance will not pay for that but… I HAVE come to the conclusion that, at least for me, there is a dramatic difference!

  2. i,m 59 yrs. old. iv,e had 5 heart attacks, 2 triple by-passes & 7 stints. i,m sure i have some kind of sleep disorder. i just want to find out what type of machine i may need. from what iv,e read & know of some of my freinds & family that ues these machines that i do want a machine thats quiet, has a humidifier, & one that offers oxygen. because i do have problems with breathing at times. thank you for your time. i also have medicare & blue cross blue shield of kansas.

  3. I have never tried a APAP or BiPAP machine before but heard from customers that they would never go back to a regular CPAP machine. My sleep apnea is not very sever so I can get away with using a ResMed S9 Elite. It’s a nice little machine.

  4. I have been using CPAP mode on an auto-BIPAP machine for about a month. I also tried the auto-BIPAP and BiLevel modes but found that with the non-CPAP modes, I still had many apneas and hypo peas that were not detected in time; and, consequently, I suffered. THe CPAP has made a major difference in my wakefulness during the day, and it has also significantly reduced a ‘flutter’ (so far it remains clinically hidden and I believe it will not only stay that way; but disappear, by God’s grace) which started about eight months ago and became very palpable (yet it cannot be detected by a Holter or Echo) and literally was frightening me to death. I suspect my problems are significantly psychological (e.g., depression runs in my family) and chronic excessive stress (relationship and job, primarily) has caused me to constantly hyperventilate in my sleep, causing significant loss of oxygen and hurting my heart. The strain would not have been so much had I not been prescribed 120 mg/day of propranalol, which was dampening my CNS and heart function TOO MUCH. In fact, I believe if I were taking propranalol now, I would probably have heart failure. IMHO the CPAP is the first line of defence that actually works (as long as you have not become clustered with low level comorbid conditions which will all work together with the apnea to deal you a sudden death blow and/or they will exacerbate it, if the apnea itself has not caused those very same conditions). I delayed using CPAP of any type for years and wish now I had listened to the sleep doc in 2005. Chronic oxygen insufficiency alters your body chemistry dramatically and causes you to die from opportunistic conditions or diseases such as cancer and heart disease. I think after using CPAP I may go to BILEVEL (which was not too bad). This is because, sometimes I pee a lot after using CPAP in the morning, and I think this may be due to the CPAP provoking central apneas and possibly exacerbating hypo peas and/or OSA, due to the constant pressure (and the fact I probably open my mouth during sleep, and begin suffocating even using the CPAP).

  5. I used an appliance in Utah and when I moved to California the doctor wanted CPAP. I have had it for a year and rarely use as my throat being small is my issue not moving my jaw forward. I have to wear a chin strap like a vise and have it totally keep my mouth closed. I have compensated for the small throat by never completely closing teeth. The in pressure does not affect me, but the exhale pressue will open my lips. I am wondering if bipap with a lower exhale would solve problem. I am seeing doctor in just over a month. He is big on the pap machines, but I just rarely use due to the discomfort and dry mouth.

  6. hi, my mom tried cpap machine covered under her medicare but she didnot meet the minimum required hours of usage of the machine so they took the machine back. she was experiencing very dry mouth and severe dizziness so much so she couldnt walk. she couldnt balance herself even to stand up and walk. simply using the cpap machine for just 2 hrs or so caused these side effects for her for the rest of the day. they even tried setting her up for the minimum pressure of 4 that they could do. they said that was the lowest they can set her for. I dont know if she has the apnea due to the obstructive sleep apnea or central sleep apnea. when she sleep at night she keep waking up and it seems like she is trying to gas some air. she sleeps with mouth closed and breaths with nose, but wakes up with in seconds of falling asleep and trys to breath with mouth. i will have to pay for it out of pocket to get her a machine, so i want to get her something that is best for her no matter what the cost is, as long as she is comfortable and able to sleep with no side effects of these machine usage when she wake up in the morning and for the rest of the day.
    please help my mom. i want her to be healthy and happy. please suggest what machine do u think i should choose to for her? and when she used the cpap machine why did she experience the side effects of severe dizziness for the rest of the day with dry mouth? please help us. god bless you!

  7. I have been using a CPAP for over 10 years now, and I seem to sleep very well because I am ok with mornings! I am at a cross-roads however, because I want to update my machine into the millennium and get one that is smaller to travel with. Now there are 2 other options, – the APAP and the BiPAP. I will make an appointment with Apria and see what they have to say. I am also pretty sure that I need an Rx for one, and since I have moved to another state, will have to find a doctor that knows about CPAP-type machines. My current doc does not. I recently got a Fitbit bracelet that monitors your sleep, and it says that about every 2 hours I am restless. I live alone, so I don’t have spousal feedback to help me. When I got my CPAP in 2001, I went through a sleep study, but I hear there are easier (cheaper!) options now. One thing I did notice was how my teeth moved a bit from my tongue pushing against them, and I hear CPAPs contribute to that quite a bit. I helped that by using my teeth-whitening mouthpiece to keep my teeth from moving. I wanted to get a new one of those too, and it was going to be about $350 from my dentist! If it’s not one thing, it’s another! ;)

  8. Sue,

    Welcome to the 21st Century. Yes, there are much smaller, more portable models that are available. You’ll need a prescription by a sleep doctor for a new machine, though. It’s difficult for most sleep doctors to keep track of the newest models that come out almost monthly, so the best they can do is to prescribe either CPAP or APAP. It’s ultimately your choice which particular brand or model you want. With the availability of PAP machines online, it’s almost to the point of having too manny choices.

    You mentioned one of the known side effects of long-tern CPAP use: dental shifting. This in theory can make your sleep apnea worse, since pushing the tech back can narrow the airway. It’s an acceptable tradeoff if you’re benefitting from CPAP.

    It’s actually normal to move around during the night. Ultimately, what’s more important is how you feel rather than what sleep study or Fitbit reports say.

    Good luck!

  9. Fatima,

    From what you’re describing, the side effect may be worse than the treatment itself. It’s like taking a pill that makes you vomit every time. Yes, there’s a chance that your mother will get used it it, but in my experience, this is a situation where you have to look at other options, such as oral appliances, or even surgery. A good sleep physician should be able to counsel her on her options. There are even other options such as Provent and tongue retaining devices. Good luck.

  10. Was advised to undergo 24hr holter due to ECG result.It turned out i have significant pauses at night 48 in total range 2.5 longest 6.6 secs.,doctors wants me to have a sleep study but insurance will not cover.,wandering if i should go with sleep study or should i opt to take the split study were in diagnostic and therapeutic are combined in in one session instead of the plain sleep study to determine if cpap would improve my condition and eliminate sinus pause.Thank you so much for your professional feedback

  11. Diagnosed with Sleep Apnea a year ago, I had been using CPAP with increasing daytime sleepiness until two weeks ago I started BiPAP and finally, I am able to get out of bed (with the help of 25mg of Adderall) and perform tasks throughout the day.
    After CPAP and APAP, BiPAP for me has been the only thing that has helped. Now, I would like to know why?! Much literature exists on the idea that BiPAP works better for some people but why? I have yet to read a study that clearly articulates the difference in outcomes.

  12. Ron,

    Thanks for sharing your story. The one main advantage that bilevel therapy has is the the pressure during exhalation is lower, so it’s easier to breathe out. However, as I point out in the post, some people prefer APAP and others like straight CPAP better. So far, there’s a lot of speculation, but no scientific explanation to date as to why this happens.

  13. Thank you Steven. Are you aware of anyone involved in the study of why some patients respond better to either APAP, BiPAP or CPAP?

  14. I took a home sleep test and it came back positive for severe apnea. So I went to a sleep center were they tried to determine the settings for a CPAP machine. When it was finished, the tech said that she maxed out the CPAP and turned it over to a BIPAP. She said that she maxed that out as well and only got about an hour of REM sleep on the machines. I’m new to all of this so what do you think would be my next course of action?