AutoPAP Exchange / CPAP gas called "Aerophagia"

[-SWS]

A quick note for new PAP machine users suffering from "bloating" or "gas". The medical term for this is "aerophagia". You can search the Internet for plenty of references to this topic by pairing the term "CPAP" with either "aerophagia" or the phrase "gastric distention". The amazing fact is that many message board posters here have mentioned that their own medical professionals were unaware of any link between PAP machine pressure and aerophagia! Yet, a Google search for the relevant terms will show that not only does such a link exist, but the relationship is a well-established medical fact.

Here's a very brief FAQ about CPAP-induced aerophagia that may help CPAP newcomers:

Q. What is CPAP-induced aerophagia?

A. CPAP-induced aerophagia is the unintentional introduction of air flow into the stomach resulting from positive air pressure (PAP).

Q. Why does aerophagia happen?

A. If the cause of aerophagia is purely related to CPAP use, then it happens simply because the air pressure against the esophageal sphincter muscles is great enough to overcome the esophageal closure that normally seals off the stomach. Other non-CPAP physiological factors may contribute as well, as aerophagia is not at all exclusive to CPAP use.

Q. How much CPAP pressure is required before air can breach the esophageal sphincter closure that seals the stomach?

A. This air-pressure threshold seems to vary from patient to patient depending on quite a few physiological circumstances. By clicking HERE you can see one college that claims: "Gastric Distention can occur in persons because the pressure needed to force air down the esophagus and into the stomach is in the vicinity of 18 – 20 cmH2O." A few days ago I happened accross yet another reference that claimed 15 cm was the magic threshold before many patients began to experience CPAP-induced aerophagia. However, depending on your own physiological architecture, you may never experience aerophagia, or you may begin to suffer from CPAP-induced aerophagia at a much lower pressure. Again I think it's absolutely amazing how many of us have posted that our own medical professionals are completely unaware of the link between CPAP and aerophagia. If your medical professional seems unaware of this medical fact, and it happens to prove both relevant and crucial to you, be sure to print plenty of reputable references from the Internet to show them.

Q. Why do so many medical professionals seem to be completely unaware of the link between CPAP and its resulting aerophagia?

A. That's a good question. My own guess is that it has to do with the fact that aerophagia does not normally manifest during a one-night PSG sleep study. Perhaps enough patients are not educating their own medical professionals about their experiences with aerophagia, since the symptoms so very often gradually disappear on their own. Perhaps it has to do with how new sleep medicine is or how vast and overwhelming the entire field of modern medicine has become. I really don't know, and your guess is at least as good as mine, if not better. CPAP-induced aerophagia ignorance within the medical field stumps me to no end.

Q. What can I do to relieve CPAP-induced aerophagia?

A. The good news is that for many of us, CPAP-induced aerophagia seems to disappear over time. Perhaps the esophageal sphincter muscles gradually strengthen with nightly "resistance workouts" introduced by Positive Air Pressure therapy. In the meantime, strategies such as using your CPAP machine's ramp button, sleeping at an incline, avoiding food and beverages late in the day just may help. At least one message board poster has reported that sleeping with their chin in a downward or tucked-in position somehow seemed to exacerbated their own aerophagia. So experimentation with sleeping position may be in order as well.

CPAP patients who seem to suffer from intolerable aerophagia (or aerophagia that does not eventually go away on its own) usually have to solve this problem by having their physician lower their air pressure and/or change PAP machine type. For many, an AutoPAP will help with aerophagia simply by reducing the mean airway pressure (MAP). For others, BiPAP or C-Flex, which reduce exhalation pressure (EPAP) seems to be in order. Pressure against the esophagus is greater during exhalation (EPAP) than during inhalation (IPAP).

Unfortunately, anti-gas or anti-bloating tablets will not help with CPAP-induced aerophagia----although other contributing gastronomical sources of gas may be helped by these medicines.

As always, consult with your physician if you notice any new or unusual symptoms when starting CPAP, including discomfort. Good luck!

[ April 05, 2004: Message edited by: -SWS ]

[-SWS]

I agree that the physiological variables vary. In fact, I think I mentioned that several times in my post above. That first reference I cited hyypertext to posted a range, which would correspond to statistical occurence driven by the physiological variances the three of us speak. That threshold number in that second reference was at odds with the first reference, only to highlight the fact that statistical interpretations can and do vary (or even be in error). So your points are very valid, although I think they reinforce what I have said above.

Despite vast physiological variances, medicine does quite often take a statistical approach. That AutoSet you use and like, Biker, differs from all the other AutoPAP designs in that it too algorythmically takes a statistical approach toward OSA treatment and efficacy versus the "physiological variance" approach all the other AutoPAP designs favor. The AutoSet's A10 algorythm limits its delivered air pressure in response to apnea type events to only 10 cm based purely on a statistical approach across the entire apneic patient population. That particular statistical approach may even achieve greater efficacy than any other AutoPAP design based on how much positive feedback patients give that machine here and elsewhere. However, that machine seemed to fail miserably for Mr. Mango, who's physiological variance did not fit within the particular statistical model employed by A10's design.

So yes, even though physiological variables and circumstances do apply here, so do statistical methods.

[ April 04, 2004: Message edited by: -SWS ]

[<goatdaddy>]

Seems like some hoseheads here just make a controversy where there was none and display a certain amount of oneupmanship.

[-SWS]

I hope I didn't come across to anyone as being unnecessarily controversial.

And I know and respect both Biker and Mango well enough to know for a fact that they both strive only to clarify subjects---even if Biker does ride a "Hardly"!

[rested gal]

I didn't see any controversy. I saw good information and general agreement between SWS, Biker and Mr. Mango. The word "However" in Biker's post, and the "Amen to that Biker" in Mr. Mango's made it appear that there had *possibly* been a misunderstanding of SWS's original comments.

I understood why SWS would want to clarify the basic agreement that all three gentleman have regarding each case as being unique to that individual, regardless of what the statisticians come up with.

I agree with Mr. Mango's statement:

"sleep deprivation caused by bad compliance is worse then a lower pressure"

[Biker]

I don't think any of us go for the one upmansip thing here...........we're all looking.........seeking information.......and learning.

Auto's can be very patient specific, there has been a great deal written about them.

I would like a chance at trying all the autos on the market for 3-6 months with their software and do a good comparison of all the units........it would be nice if possibly 10-20 people could be involved...........Any ideas as to how we could pull this off?

Good Sleep,

Biker

[rested gal]

Biker, I'll loan you my 420E for a month if you'll let me try out about half the masks in your collection...preferably the newest ones!

[-SWS]

Biker, not a bad idea. I wouldn't mind comparing various AutoPAPs out there as well. That would certainly be a tough one to pull off, though.

A formal co-op type group would undoubtedly carry liabilities, need to see prescriptions, perhaps even be insured/licensed to satisfy legal requirements. Perhaps Rested Gals' idea of informal trades might be the way to go. Even that concept carries quite a few hurdles to work out.

For instance, I would be very comfortable shipping my RemStar Auto to you since you have been around since nearly the inception of TAS and are a well-known apnea activist in your region. Your reputation precedes you in more ways than just one! But I wouldn't be comfortable loaning my AutoPAP out to new and unknown TAS member #4025 A.K.A. "Joe Weasel".

Perhaps some informal system of arranged trades with some kind of built-in 2-way trust method or criteria? That 2-way trust relationship might not need to be completely unilateral, for that matter. In the example above, I would easily trust sending you my AutoPAP. Since you know much less about me, or better yet "Joe Weasel", you might feel more comfortable waiting until you received an AutoPAP via UPS before finally sending yours out in exchange to some unknown trading partner. Perhaps some informal means of a third party securing deposits or acting as a central go-between/hub for such resource sharing. Again, liabilities and legalities may need to factor in for that third party. Perhaps a central database maintained somewhere that contains contact information as well as listings of who has equipment to exchange, and what they are hoping to receive in exchange---this would even make informal "circular" or three-way trades possible.

Other caveats to consider: sterilization of equipment, calibration/performance-verification of equipment, varying technical capabilities of those in the AutoPAP loaner circle, accomodating international versus domestic exchange, recourse for someone borrowing an AutoPAP that instantly proves incompatible for them, etc.

Any other ideas kicking around out there about Biker's idea? It is alluring!

[ April 04, 2004: Message edited by: -SWS ]

[rested gal]

I promise not to let my dog use Biker's masks as chew toys, if Biker swears he won't test the durability of my autopap by running his bike over it.

[frequenseeker]

Let's have eBay manage the PAP "circle" - their system has worked for similar transactions involving verification and security of participants, don't you think?! We could post feedback for instance, of performance on various parameters...

[sleep talker]

I think it would be a great idea to post more specific info about our auto machines. As some of you may know, I own a Resmed Spirit, P&B 420E Auto-CPAP, and a Respironics Virtuoso. I've been trying to find time lately to correlate some of my night studies and come to conclusions about how the different algorhythms fit my own unique situation. The information would mostly be on the first two machines. I don't use the Virtuoso anymore for reasons obvious to those "in the know" about auto-CPAP technology. I mostly use the machine to blow out my hose after I've washed it.

One of the reasons I've not posted side by side comparisons is lack of website space and knowledge on how to up-load data. I'm asking a friend about those FTP programs used to do the uploading, and I'm creating space now on my service provider (Charter). When ready, I will post my results and link to my new web space for pictures and graphs.

I too would really like to try a Remstar Auto for a few weeks and see how it works for me.

Chris

[-SWS]

Wouldn't that be nice if we could somehow talk each manufacturer into donating at least one of each AutoPAP model toward our collective reviews?

Right now my RemStar Auto exibits an LCD error message E-83 if I set the bottom pressure as low as 5.0 cm. It's still under warranty and my DME is waiting to hear specifics back from Respironics. Once I get that straightened out I'd be glad to exchange for a few weeks with you, Chris, if you're still interested by then. I just don't know how long it's going to take my DME and Respironics to get that E-83 error straightened out.

[Biker]

SWS......very good explanation.

However.......the threshold for aerophagia problems is dependent on the patient not on any preconceived numbers set forth by a medical study. I ended my aerophagia problems by going on an autopap 4 yrs ago. I had problems at 10, 11, and 12 cm of airpressure, the sphinctre valve in my case was damaged badly by acid relux which was caused by my OSA.

One thing we as patients must always remember is that we are all physiologically different.....there are too many variables to make and set any type of NORM for all of us.

The most important thing for anyone with OSA to do is educate themselves............treatment of OSA is a relatively new field............read and learn.


Good Sleep,
Biker

[Mr Mango]

Amen to that Biker. From the snout to Aveoli there is many variables, from opinions, from experience it is a climate of misunderstanding and of personal choice.

OSA treatment is learning as it goes. God help us all if down the track we come against oops. Maybe that pressure, that type of machine or whatever if more dangerous then the treatment itself.

However do you thnk we are out of the lab rat situation?

I am doing so much better on 12 pressure then the 14 - 16 pressure I am suppose to be on at 30lbs heavier. Doesnt make sense but it works. My argument stands that sleep deprivation caused by bad compliance is worse then a lower pressure.

But your argument is right saying thats good for you mango but I cant do that without feeling like whatever.

Mango

[sleep talker]

Thanks for that generous offer SWS, but the obligation of using and caring for someone's equipment is probably more than I'd want to take on at the moment. I'll think about it though, in the future, if I really get curious about the Remstar Auto. I haven't done enough time on my 420E at the moment to evaluate that machine properely. I'm still partial to the Spirit and find myself using it more than the 420E.

My real problem lately is I'm spending too much time on the computer during the day and it screws up my sleep. I need to get outside more often and get some fresh air.