APAP vs. CPAP

avi123 wrote: I don't think that -SWS was fair by posting the above links to ComplexSAS (which may require ASV machine), and to the BiLevel, in this conversation, b/c the topic is APAP vs. CPAP.

Whenever it appears that -SWS was not "fair" in what he posted, it is worth rereading his posts and links more carefully and examining the context, since, in my opinion, he is one of the most insightful and considerate posters posting on the Internet.

And now, if I may, here are some personal reactions to your recent posts in this thread:

avi123 wrote:There are definite advantages to APAPs that many pyhysicians and CPAPers don't know about.

And disadvantages. No one knows everything. But each modality has specific advantages and disadvantages for particular individuals. That is why blanket statements about forms of PAP therapy are rarely of much use, IMO.

avi123 wrote: It could be because most sleep clinics don't do APAP titrations,

The marketers of APAPs market them as not requiring any titration at all. The idea of titrating an APAP is mostly unique to this board, as I understand it. Setting a range that considers the titrated pressure is a concept understood by some docs and techs and RRTs, but that is not exactly 'doing an APAP titration.' Usually when pros speak of 'APAP titrations,' they mean using an APAP over several days/weeks to find a single pressure that will address most events and doing that instead of, or occasionally in conjunction with, a lab titration. But I don't think they mean finding the right range of pressures for APAP use.

avi123 wrote:and a physician rather not take the responsibilty.

Docs take full responsibility for diagnosing and prescribing. They do not generally take responsibility for that which falls outside their job description.

avi123 wrote:Also, there several underlying medical conditions such as COPD, Heart problems, and Central Sleep Apnea syndrome, whereby APAPs should be avoided.

Perhaps the better wording would be "may be contraindicated." In some cases, people with those conditions benefit greatly from certain forms of APAP, depending.

As for patents, they are rarely a basis for judging present medical views of the different forms of PAP therapy. That isn't what patents are for. Patents are for the lawyers, not the docs.

DannyCPAP wrote:what is the difference between these machines and how it is decided which one to prescribe?

Hi Danny,

They have found that the auto adjusting APAP is useful to tritrate - actually modestly outperforming the in lab "one night" way of doing things in a recent study (see the Journal Sleep July). I am not supprised since we do not sleep the same nor is our body the same is it was another night.

Since APAP never gets AHI as low as CPAP can my way of doing things is to use CPAP and monitor it very regularly and adjust my lifestyle as much as I can to keep the AHI low and the breathing instability low as well. With CPAP my body can get used to a single pressure. APAP will always permit some AHI through the gate and controls breathing instability by keeping the pressure as low as possible as much as possible (although I suppose when you go to high pressure you tickle that dragons tail indeed!).

In the future I hope we see such things as an APAP analyzing the breathing audio to determine oncoming AHI or breathing instability intervening with changes in overall pressure, breathing phase based pressure, and enhansed rebreathing space adjustments. For now I guess we do the best we have with what we got,

jnk, I don't know why your above post (to my attention) reminds me of this from Qoheleth (by NIV):



2 “Meaningless! Meaningless!”
says the Teacher.
“Utterly meaningless!
Everything is meaningless.”


3 What do people gain from all their labors
at which they toil under the sun?
4 Generations come and generations go,
but the earth remains forever.
5 The sun rises and the sun sets,
and hurries back to where it rises.
6 The wind blows to the south
and turns to the north;
round and round it goes,
ever returning on its course.
7 All streams flow into the sea,
yet the sea is never full.
To the place the streams come from,
there they return again.
8 All things are wearisome,
more than one can say.
The eye never has enough of seeing,
nor the ear its fill of hearing.
9 What has been will be again,
what has been done will be done again;
there is nothing new under the sun.
10 Is there anything of which one can say,
“Look! This is something new”?
It was here already, long ago;
it was here before our time.
11 No one remembers the former generations,
and even those yet to come
will not be remembered
by those who follow them.

OldLincoln wrote:sws said there is a white paper posted that reports compliance is equal between APAP and CPAP. That must be recent as the studies I read a few years ago reported CPAP compliance at 50% and APAP compliance at 70%.

When my doc hesitated to script me an APAP I asked him why he would script anyone a solution that is only 50% successful when there is a solution proven to be 70% successful. Of course I had tried the CPAP for some time and couldn't take the bloating. But he did start thinking about it.

I haven't yet seen the 50%/70% compliance study, OldLincoln. Thanks for mentioning it. If I can find that study, or the other studies, I'll link to them in this thread.

avi123 wrote:

-SWS wrote:

-tim wrote: For most cpap needs, apap is easlier to adjust to.

There's a white paper kicking around somewhere on this message board. That particular study concluded there was no signifiant difference in patient compliance between CPAP use and APAP use. But I think we can question any methodology that runs APAP machines wide open, at 4cm-to-20cm. Intuitively, I think that above statement may be true. However, as epidemiology and empirical evidence go, I'm not aware of proof. I do know some people fare better on CPAP, others fare better on APAP, while others seem to do equally fine on either machine type. This message board has a long history of claiming APAP is superior to CPAP. So far researchers seem to have difficulty proving that...

I suspect anyone who recieves good control of obstructive SDB at low, fixed pressures around say 7cm or less will probably not see increased benefits from APAP. That said, I think it's nice to have an APAP machine, since it can run either CPAP mode or APAP mode. Patients can then decide if one of those two modes lends an advantage relative to their own sleep and physiology nuances.

-tim wrote: But there are reasons for pure CPAP mode (which tends to lead to VPAP in a few years).

I haven't heard or read about that tendency. Do you mind my asking on what you based that statement about tendency? Here we can see a statement suggesting that CompSAS patients tend to find APAP mode more destabilizing to central breathing than CPAP mode:

CPAP therapy may be more or less effective in individual patients, but automatic CPAP machines should be avoided.

http://www.chestnet.org/accp/pccsu/comp ... a?page=0,3

Similarly, some patients find spontaneous BiLevel/VPAP mode to be more destabilizing to central breathing than CPAP mode:
http://journal.publications.chestnet.or ... id=1083869

I haven't stumbled across any conclusive evidence that pure CPAP mode tends to lead to a need for BiLevel/VPAP in a few years. Our message board documents plenty of patients in the U.S. who presumably need BiLevel from the very beginning----but must first prove failure on CPAP for the sake of satisfying insurance requirements. However, that particular trend seems based more on inane insurance bureaucracy than physiologic progression itself.

Comment,

I don't think that -SWS was fair by posting the above links to ComplexSAS (which may require ASV machine), and to the BiLevel, in this conversation, b/c the topic is APAP vs. CPAP.

The links I presented were not intended to serve toward an APAP -vs- CPAP comparison, AVI. They were trend/epidemiology statements relative to -tim's comment that a CPAP-modality requirement will lead to BiLevel use in a few years. I have yet to hear about that trend. If that type of progression is described in literature, I would like to read about it.

Avi, that was nice of you to volunteer as this thread's referee of thread relevance.

-SWS,

1) as to the relevancy of of this thread, I wonder to what? i know one thing and that is that I had to pay from my pockets $580 [re-edit to $850] for a new S9 Autoset's flow generator section while being on Medicare insurance. Was it relevant for me? Very much so. This APAP changed my treatment entirely for the better, even if it has to do with Drs Colin Sullivan and Michael Berthon Jones some dozens of patents embodied in this APAP machine. As to jnk pooh poohing these patents by posting: "As for patents, they are rarely a basis for judging present medical views of the different forms of PAP therapy. That isn't what patents are for. Patents are for the lawyers, not the docs." Well, as a holder of some 15 patents in the semiconductors production field, I know it that jnk's statement on it is real bull.

2) could this be the "white paper": viewtopic.php?f=1&t=46429&start=0&st=0& ... ow#p416819

avi123 wrote: . . . i know one thing . . .

I don't doubt that.

avi123 wrote: . . . Was it relevant for me? Very much so. This APAP changed my treatment entirely for the better, . . . .

A tool put to good use is a beautiful thing and makes for a wonderful anecdote.

avi123 wrote: . . . has to do with Drs Colin Sullivan and Michael Berthon Jones some dozens of patents embodied in this APAP machine. . . .

The fact is, though, that the machine would work just fine if there were NO patents involved. Patents had to be made in order for business to be assured they could make money manufacturing the machines. That is the concern of the manufacturers and lawyers, NOT the sleep docs who write the Rx.

Sometimes old patents give clues as to how machines do what they do, but sometimes not. I believe that the business patents and the resulting hidden, proprietary nature of the algorithms are two reasons many docs are not on board with the whole APAP thing. It smacks of unfounded claims of businesses selling directly to patients while hiding info from docs. Companies are less than forthcoming with how their machines work and refuse to make clear which patients would benefit most from their particular approach, as opposed to another company's approach, protected by its particular patents. Patents tend to get in the way of medical practice, in that sense, as a necessary evil for the business end of things.

Docs especially don't like playing experiemental try-and-see with therapies that should be publicly explained to clarify which end of which bell curve a certain algorithm is aimed at--who specifically benefit from which approach. In my opinion, business and law aside, the best thing medically for patients would be for ResMed and the other manufacturers to let go of their patents so that the medical end of things would take a little more precedence over the business side of things. The companies could then compete on other aspects of their machines instead of patented approaches to medical efficacy.

avi123 wrote: . . . As to jnk pooh poohing these patents by posting: "As for patents, they are rarely a basis for judging present medical views of the different forms of PAP therapy. That isn't what patents are for. Patents are for the lawyers, not the docs." Well, as a holder of some 15 patents in the semiconductors production field, I know it that jnk's statement on it is real bull. . . .

I'm known for that here. I'm the bull guy.

I'm sure all the doctors are very proud of your semiconductor patents and use them to choose which semiconductor therapy is best for their patients all the time. Good for you!

I like APAPs; I use an autobilevel, myself. But I believe that some patients who are sensitive to pressure changes during the night, and who remain sensitive to that over time, would feel better in the mornings if they found one pressure that worked for them and then they stuck with that.

Below are three APAP -vs- CPAP papers I found using the Google Scholar search engine:

http://content.karger.com/ProdukteDB/pr ... tNr=233072

http://www.ncbi.nlm.nih.gov/pubmed/17148931

http://www.journalsleep.org/Articles/300208.pdf (this link is a PDF file)

AVI, that's not the study I had in mind. That discussion you linked to refers to a bench study comparing various APAPs. Close, though! Thanks for looking.

More from 'the bull boy,' me:

To me, the CPAP vs. APAP studies have it all wrong. The question that should be studied is this: Is there any documented proof in the compliance figures that CPAP results in higher compliance rates than APAP for uncomplicated OSA? If no scientific study has proven the advantages of denying patients APAPs, then it makes no sense to deny such a common and cheap comfort feature for use for such a serious condition--especially a feature that has the added practical potential to save a fortune in lab-titration studies and to provide added information to docs, RTs, and patients alike.

I can't prove that a swivel-rocker-recliner makes me any more likely to sit down in my living room than a large rock would--because, when I'm tired, I'm going to sit down either way. In that sense, both types of chair are equal as a place to set down my oversized butt. But I sure as heck know which chair I prefer to use in my living room, studies be darned--especially if the rock costs basically about the same as the recliner.

Same with APAP.

jnk wrote: The question that should be studied is this: Is there any documented proof in the compliance figures that CPAP results in higher compliance rates than APAP for uncomplicated OSA?

Which patients would you exclude? I think most of the APAP studies tend NOT to select for patients who present a prominent central component. There are other patients who don't present a prominent central component, but find fixed pressure less disturbing than APAP pressure changes.

One selection-bias risk in designing a study methodology is selecting for patients who do better with APAP mode. When you deselect patients who fare better on CPAP rather than APAP, then you end up without comparative epidemiology. However, a study designed with APAP-favorable selection bias at least validates that there are some patients who fare better with APAP. But case-studies/anecdotes alone would serve that non-epidemiologic premise without incurring hefty re$earch funds, staff, and other resources.

I would think the task of designing APAP-favorable outcomes in methodology is not hard. But the methodology itself might receive epidemiology rejection in peer review. Additionally, researchers with no conflicts of interest try hard to avoid selection bias. Manufacturers arguably incur selection bias without even trying----based on a paradigm that embraces and promotes their products. So if one were looking for pro-APAP studies, PAP manufacturer web sites might be a good place to look for white-paper citations... If one doesn't find blockbuster pro-APAP citations at the manufacturer web sites, then I suppose we have to ask why that is.

-SWS wrote: . . . Which patients would you exclude? . . .

I would preselect for

jnk wrote: . . . uncomplicated OSA . . .

As you know, I was being facetious as the bull guy, but being so to attempt to make the point.

Also, to me, it is easy to confusingly entertwine discussions about (1) studies of constantly varying pressure all night every night vs. fixed pressure all night every night (which, as I understand it, is mostly what the scientific studies of APAP vs. CPAP are about), and, on the other hand, (2) the choice between, and desirability of, two machines--one being a CPAP that can auto-titrate when needed (commonly called an APAP) and the other being a CPAP that lacks that ability.

Discussing studies of the modalities of treatment used all night every night is to me a different question than discussing the usefulness of having a machine with an added capability that costs very little to add that doesn't require constant use of the feature. In other words, having a machine that is capable of occasionally running in auto-titrating mode is not the same thing as forcing a patient to always use auto-titrating mode. So studies about long-term treatment with fixed or varying pressure are not the end-all of discussions about the usefulness of having the feature available on the machines we buy.

So, to me, it is useful to note the difference between having an APAP and using it in APAP mode full-time. Adding a feature to a machine, such as the ability to auto-titrate, and doing so without subtracting any features, couldn't possibly damage the usefulness of the machine. That is my point. Or at least the one I think I'm making at the moment. I tend to ramble sometimes, don't I?

No study can prove that having the feature available damages the usefulness of the machine.

I don't think.

But then, I ain't no science dude. I'm just the bull guy. I like my job.

(I'm in a good mood today, so it is OK to rip the above to shreds, if that moves the discussion along. I can handle it this time. )

Hi, the following could be the "white paper" that -SWS is thinking about:

wiki/index.php/AutoPAP

I am wondering who wrote this?

I like the section APAP myths, reminding me of
"The Myth of the Income Portfolio",
written by Harold Evensky, CFP.

As to the debate of APAP vs CPAP, I am annoyed that I have not paid attention to my S9 Autoset manufacturing date of 2009, when I bought it from my DME at the beg. of 2012. It is protected by patents only to patent # 7,537,010. So I am missing other patents, for example # 7,730,886 dated June 8, 2010.

avi123 wrote: . . . I am wondering who wrote this? . . .

Some of it is by Mile High Sleeper and some by sleepinginseatle, it looks like.

Good stuff. Gives both sides. Says it better than I could. I should just shut up and point to that from now on, eh?

I made the argument somewhere above that the retail cost of APAPs should drop to that of CPAPs if all they made were APAPs on the basis that if a steady single pressure was warranted they could always set the APAP to CPAP mode, but not reversed. The basis is that the mfg supply chain is simpler as well as the distribution line. I realize some do better on CPAP and if I remember right, centrals are better handled with a steady pressure.

reading this over it sounds like a circular argument in that if all they made were APAP there won't be a CPAP price. What I meant was the CPAP price if they still made them. That's the Medicare argument of a single price for either.

OldLincoln wrote:I made the argument somewhere above that the retail cost of APAPs should drop to that of CPAPs if all they made were APAPs on the basis that if a steady single pressure was warranted they could always set the APAP to CPAP mode, but not reversed. The basis is that the mfg supply chain is simpler as well as the distribution line. I realize some do better on CPAP and if I remember right, centrals are better handled with a steady pressure.

reading this over it sounds like a circular argument in that if all they made were APAP there won't be a CPAP price. What I meant was the CPAP price if they still made them. That's the Medicare argument of a single price for either.

Comment,

It's not only a question of price. A study published in 2008 about APAPs concluded that:

In conclusion, titration remains, surprisingly, not evidence based almost 25 years after the first description of CPAP. Predicted formulas do not agree with each other, manual titration is still an art, and APAP seems to fail so frequently that it may be unreliable. Promises of lower pressures with APAP devices are not fulfilled: the device used in this study yielded the highest fixed pressures. The promise of higher compliance has been almost impossible to prove, the majority of studies showing equivalent results between fixed CPAP and APAP treatments. Physicians relying only on APAP devices for titration should remain extremely cautious, and react rapidly in cases of low adherence or compliance in the initial months of treatment. Marrone and coworkers10 should be commended for their very detailed study, questioning many widely accepted assumptions and calling for better studies of the titration process.

Excerpt,

After 10 years, the concept of APAP has been extensively applied, and every company constructing and selling CPAP machines has its own APAP device, working on some proprietary algorithm. Many patients with a diagnosis of obstructive sleep apnea are “titrated” using APAP devices, and then sent home with a fixed CPAP machine working at P95 pressure levels. Many patients even get APAP devices for long-term treatment. The use of APAP devices for diagnostic purposes has not yet convinced the medical community, but efforts are still being made.