Theories re Cpap vs Apap?

[Julie]

Well, I've read a lot lately about Cpap possibly being better for you (or at least some of us) than Apap, however we might 'feel' subjectively. What I wonder is that if it's true, regardless of Apap feeling more comfortable, does that mean the majority of us (on Apap) are going to be sorry in the long run? What do you think (Snoredog, any input?)?

[Wulfman]

Well, I've read a lot lately about Cpap possibly being better for you (or at least some of us) than Apap, however we might 'feel' subjectively. What I wonder is that if it's true, regardless of Apap feeling more comfortable, does that mean the majority of us (on Apap) are going to be sorry in the long run? What do you think (Snoredog, any input?)?

This is REALLY one of those "it depends" questions. If a person has too low of a minimum pressure, they're going to have far too many events taking place if and until the pressure is able to get up there where it needs to be. If a person's sleeping is bothered by the pressure changes, then that's another reason to stick with the straight pressure. There are going to be SOME events get through either way.......APAP can't respond fast enough to get them......CPAP pressure may not be high enough to clear them all.

Other things that need to be taken into consideration are things like GERD and aerophagia.

EDIT: I don't like to see this therapy characterizing those who DON'T have an APAP/Auto as having an inferior machine or therapy. There are always advantages to having more options available, but I believe the vast majority of users of this therapy can have good therapy using single pressure.


Den

[dsm]

Personally I would argue that Apap is better for a person if it is set up correctly and manged well.

The problems I see with Autos are (as Den has pointed out) to do with RTs sending them out the
door set to the widest range of pressures & that to many of us more experienced folk, is as good
as sending a failure out the door.

The early big plus that Autos offered was their initial ability (over and above all other models at
the time - incl Cpaps & ilevels) to provide nightly detailed data tat included minute by minute AHI
data. That feature made them the cpap of choice.

Today almost all new cpap brands provide an ability to get that nightly AHI data, Most Bipaps
(except the S/T gray model & some of the earlier Synchrony models) also provided nightly
AHI data. Vpaps all offer that data even the latest Vpap Adapt SV now provides it.

The reason the AHI data has become such an issue is that it is the easiest form of feedback
for lay people to understand.

Getting back to Autos. The tighter one sets the range the more effective the machine will
be in meeting its design goal & that goal (as stated in most documents supplied to the DHA)
is to improve the therapy for users and to try to eliminate the biggest reason why people
abandon therapy - breathing out against a constant pressure when that titration pressure
is not really needed at all times. Autos seek to improve therapy by running at the lowest
pressure they can in order to make that exhaling less of a burden. The problem is that if the
Autos start pressure is set too low for a particular person, the can expect to see higher AHI
numbers when a pattern of events commences, as the Auto can only raise pressure slowly
(over minutes) in response to a pattern of events. So AIs and HIs slip through.
#2 (revised above para)

By starting the pressure 2-3 CMs below titration & setting an upper limit 2-3 CMs above
titration, one is going to get a lot better results than leaving the start CMs at 4 or 5 or 6
etc: CMs if one's titration was 10 or above.

The main purpose of the vast majority of new designs in CPAPs that are to be sold to the
wider public, is to improve the therapy for the bulk of users. Any feature that eases the
burden of breathing out against the CPAP fixed pressure, is most likely going to improve
compliance levels.

For myself, I prefer a Bilevel as they offer the best exhale relief available. The Auto
Bilevels then offer the benefits of Auto adjusting pressure but as with a plain Auto, the
settings need to be finely tuned & the ranges set to the minimum gap between min
starting pressure & max self adjusting pressure. The ipap epap gap is the big bonus.

DSM

[ozij]

Well, I've read a lot lately about Cpap possibly being better for you (or at least some of us) than Apap, however we might 'feel' subjectively. What I wonder is that if it's true, regardless of Apap feeling more comfortable, does that mean the majority of us (on Apap) are going to be sorry in the long run? What do you think (Snoredog, any input?)?

That's the first I've heard of anyone denying the validiy of subjective feeling - and I wonder where you've read it.

Some people report they sleep and feel much better when they either switch their machines from APAP to CPAP or narrow the range. Others report the opposite.

I would like to read the studies you're referring to, if that's what they are, or see the links.

It is as DSM said: The major problem with APAP is when it is given to people with a 4-20 range, by doctors or RTs who buy the companies sales blurbs. Time and again, we see that the machines can't pre-empt events that efficiently and can't learn from experience that "if you drop too far down the user will have too many events, so just don't drop so far". When the minimum pressure is too low, therapy is not good enough - and the user feels it..


For people with positional apnea, or those whose pressure needs vary tremendously between various stage of sleep, letting the machine go high only when necessary is very good.

For the majority (and that means there will always be exceptions), autos are pretty good at finding a 90% pressure when the range is wide (that is, funtioning as auto titrating machines). They not half as good as giving good therapy when the range is too wide. Those hours spent spent at sub-optimal pressure, aquiring the events needed to have the machine raise it, are not too good for anyone's health.

I firmly believe xPAP (APAP CPAP or BI-level) therapy is one of the cases where how you feel is an excellent indicator of how the therapy is working (or not, as the case may be). However, if studies show differently - I would, as I said, like to read them.

O.

[Snoredog]

depends on what you are using to measure that benefit, AHI, how the person feels, or how long they use the device.

If your CPAP pressure is 8 cm and you use an autopap set 8 to 20 cm there should be no difference, if anything you get better treatment if the pressure is allowed to address a rouge snore or flow limitation.

if your CPAP pressure is 12 and you use an autopap set 10 to 20 there should be no real difference either, above that pressure it is only going to be chasing a snore or FL on most of the machines out there.

if your CPAP pressure is 8 and you use a 6.5 to 20 setting you probably won't notice any difference other than it is easier to fall asleep or therapy more comfortable. Newbies nearly always dislike the noise, dislike the higher pressure, the object is to get them comfortable tolerating the therapy then tweaking things to improve the therapy. I've read techs say before we find their pressure and add 2 cm to it. Well if you do that with me my sleep architecture falls apart. I've yet to use a autopap that didn't find my ideal pressure.

autopaps always get a bad rap due to ignorance on the Doctors part for incorrectly setting them up. A patient rarely receives a machine set up correctly for their continued use, they either set them up for failure by allowing the DME to set the machine which normally results with the machine going to the patient set 4 cm to 20 or the default settings. AHI and Leak info if optionally needed to be set for display will be disabled. No Ramp setup, the list goes on and on.

All the damn doctors know is to to give them a plain jane cpap and a swift mask, get outside that configuration and they brain dead.

All it takes to manage this therapy is a bit of common sense and a little knowledge.

I think a better comparison would be to compare compliance rates between apap and cpap, because if you are NOT using any machine how can CPAP be better? Failure rates for CPAP therapy overall is what 50%? I wonder what that percentage would be if they gave every patient an autopap set up by someone who actually knew what they were doing?

[carbonman]

My grand, expand my horizons in cpap, experiment last night ended after 15'.
I wanted to see if straight cpap was for me....I folded after 15'.

Sleep doc sent me home 2months ago, 8cm.
After I got my auto and started reading here, I have slowly moved up
to 11min/13.5max. In the last week AHI has been in the 1.+ range, last night 1.2.
I don't use ramp and I am very comfortable w/my mask and the pressure.
I am sleeping better than I have in years and my body is telling me the same.
It comes in small increments, a little better each night.

I set the straight cpap to 11.5cm. It was the exhale that I could not take.
I felt like my head was a balloon being blown up.....there was no relief.
Is that a common feeling?

How best to make this transistion? or is there any reason to make this transition?

..as SD says, "if it ain't broke.....yada, yada, yada"

[Julie]

Ozij - The 'subjective' feeling I mentioned was not something I read, just something I put into the question because what I was asking about was having read that Cpap alone (in studies) is apparently superior in the long run in terms of health consequences (tested by MD's) rather than how patient's may feel at any given time - but again that part is assumed, imagining that MD's were not concerned (in that study) about patient's responses vs their lab results. In other words should we all just be using Cpap (regardless of anything else) based on what MD's say is a better long term result taking into account all or any 'connected' medical conditions.

[CorgiGirl]

I've found some articles that say APAP is just as good CPAP. The links below are from PubMed.com (the National Institutes of Health database of professional medical articles). They only contain the summary, but the full articles are available for a fee, I'm sure.... You might check with your local public library since they may have some of these in their databases, if you're interested in getting the whole thing.

http://www.ncbi.nlm.nih.gov/pubmed/1733 ... d_RVDocSum

http://www.ncbi.nlm.nih.gov/pubmed/1714 ... rom=pubmed

[Julie]

Hi, well the first study (PubMed) only looked at results after 6 wks, not 'end-of-life', and at the risk of being argumentative I'm referring to things I've read (don't remember which articles though) saying that over the long term, people were better off having used Cpap... that's all.

[CorgiGirl]

Very few studies are "long term." I haven't seen any stating that CPAP is better than APAP that fall into that category. If you know of any, please post links.

[Wulfman]

There are no "long term" studies.......and most of the comparison studies of APAP vs CPAP were "rigged" (IMO) due to the fact that the APAPs were set to wide open pressure ranges.......ain't hard to conclude the outcomes of those studies.

Here's one:

http://www.chestjournal.org/cgi/content/full/131/5/1393

Den

[RipVW]

Yep, APAP, properly managed, is DEFINITELY better, in my view. I dread the day my APAP fails, which will require me to temporarily use my old CPAP backup machine. My APAP adjusts nightly depending on my pressure needs, and I believe those changes enable me to keep my VERY low AHI.

[dsm]

Ozij - The 'subjective' feeling I mentioned was not something I read, just something I put into the question because what I was asking about was having read that Cpap alone (in studies) is apparently superior in the long run in terms of health consequences (tested by MD's) rather than how patient's may feel at any given time - but again that part is assumed, imagining that MD's were not concerned (in that study) about patient's responses vs their lab results. In other words should we all just be using Cpap (regardless of anything else) based on what MD's say is a better long term result taking into account all or any 'connected' medical conditions.

Julie,

My approach is simple - dump CPAP machines & make em all Bilevels

Then if someone wants the best & most expensive version, sell em Bilevel Autos.

St raight CPAP is the dumbed down least complicated technology but as we all
know has many unpleasant side effects related to getting started on the therapy
and to managing complications like mask leaks, aerophagia, compliance!.

All the more sophisticated variations of CPAP were and are designed to try to
make the CPAP experience more tolerable.

Should we all just revert to CPAP, absolutely not , but those of us who take
control of our therapy and experiment a bit & read what others have discovered,
are sure in the best boat. MD's from their perspective may well argue that Autos
and Bilevels & Servo Ventilators are all complications & make their work harder.
I think that some professionals don't like having to work too hard for their big fees.

I can sure think of a few I know


DSM

[ZIFF]

.

[Hose_Head]

Wufman wrote:

This is REALLY one of those "it depends" questions. If a person has too low of a minimum pressure, they're going to have far too many events taking place if and until the pressure is able to get up there where it needs to be. If a person's sleeping is bothered by the pressure changes, then that's another reason to stick with the straight pressure. There are going to be SOME events get through either way.......APAP can't respond fast enough to get them......CPAP pressure may not be high enough to clear them all.

I can concur with this comment. My Dr prescribed me for 12 and 5 cm H2O on my auto. With that, I found that my AHI was hovering around 3.5 or worse. My data showed that my 90% pressure was around 9, with times where my auto-pap would "chase" events all the way up to 12. After reading the experiences of others in the forum, I reset my pressures to 12 and 7 (a very minor change in my opinion). The result has been reduced AHI to just over 1, with 90% pressure of 8.1 cm H2O, and my machine never goes above 9 cm H2O. There's not much advantage to my use of an auto with these settings, but I'm happy with the results. I'd probably get similar results in straight CPAP with pressure of 8.

For the record, I'm using an M Series Auto with humidifer, Aflex =2, no ramp and an Activa mask.