CPAP vs APAP vs BiPAP (poll)

[jlk]

. . . the low number of newer studies surrounding APAP vs CPAP . . .

What's to study?

APAP can solve some problems and can make therapy more comfortable for some. Anecdotal is good enough to prove that without studies. Insurance in the U.S. doesn't care which you get here, since CPAP and APAP are the same insurance code anyway, meaning insurance never even finds out which you have, as I understand it.

Some studies were designed to see if an APAP set wide open, 4 cm to 2O cm, could treat as well as CPAP. The answer is: 'Yeah, usually close enough for most people.' That answer to that question, though, doesn't much matter to many here, since many of us raise the minimum on our APAPs to within a cm or two of what is needed to prevent apneas anyway. That one or two cm lower can make all the difference for comfort, yet allow treatment virtually as effective as using straight CPAP one or two cm higher. No scientific study is gonna care about patient comfort and preference, though. Which is a shame, given the dismal compliance rates with PAP therapy.

Other studies were designed to see if APAP is an advancement as a form of treatment over CPAP, as far as, for example, dramatically increasing compliance and preventing more events from occurring. The answer to that was: 'Nah, not really.' So some research docs then said: 'Eh, why bother?--CPAP does the job, so who needs APAP?' They considered APAP a failure since it wasn't the Holy Grail of treatment it was advertised to be at first. Of course, the negative feelings about APAP were mostly held by scientists who were not personally using PAP therapy of any kind. So who cares what they think? Docs who actually practice are, or should be, interested in what helps individual patients.

As best I can tell, the consensus around here, with a few notable exceptions, is that you get APAP so you can figure out over time whether you, as in YOU PERSONALLY, do better in APAP or CPAP mode. That way, even if you end up usually using CPAP mode, you still have APAP mode available for money-saving mini-home-titrations any time you or your doc or RRT want. In that sense, it is a no-brainer. Again, no study is gonna prove that.

Many have found they end up using straight CPAP mode most of the time once they are used to treatment. But they are still glad to have APAP capability at their fingertips to use at any time they need to. Running an APAP in CPAP mode is not in any way a failure of APAP. But it IS a testimony to the fact that no one has yet discovered anything that comes close to beating, in any substantial way, plain ole CPAP for effective treatment of OSA. That's why one's opinion of APAP often hinges on whether one considers APAP (1) 'an added feature that is included on some CPAP machines' or one considers APAP (2) 'an at-one-time-intended replacement for CPAP as a whole that failed to become that.' Two people with differing perspectives on that can go around and around without ever understanding the other's point of view, since they are actually discussing completely different concepts when using the same word: APAP.

In my opinion.

My sentiments, exactly. Well written. john

[Muse-Inc]

One thing that hasn't been posted yet regarding an APAP, namely, for those of us plagued by congestion, an APAP is able to change pressure in response to how congested (smaller) our airways become.

[jonquiljo]

One thing that hasn't been posted yet regarding an APAP, namely, for those of us plagued by congestion, an APAP is able to change pressure in response to how congested (smaller) our airways become.

Most of my problem is upper airway and congestion. While I use inhaled steroids, some nights are better than others. APAP works well and delivers what I need depending on how I am breathing and how (what position) I am sleeping. But I took a while to titrate up a lower limit to get to that point. When I started at 4-20 it was not very helpful. Now my AHI is 0.1 to 0.4 pretty much every night.

[DoriC]

This might be of interest as it just happened recently. We discovered early on that Mike was very sensitive to pressure changes with Apap which was causing arousals and leaks so aftera few months of experimenting and guidance here we settled on straight pressure of 12cms, titration was 13cm but he could never tolerate it. That solved the problem and he slept on Cpap for over a year. I experimented with Apap again about 6months ago and he did well at 10.5-13 with the same good results(90% 11-12),AHI always under 2. Just before Xmas he began to exhibit daytime sleepiness and other pre-cpap symptoms again but with no change in data results. I changed his pressure back to Cpap at 12cms last week and he seems better now. So that was important information for me to know. Apap is invaluable for these in-home titrations to make sure you're on track and to monitor any changes. I'm glad I have an Apap even if I rarely use it.

[Jayjonbeach]

This might be of interest as it just happened recently. We discovered early on that Mike was very sensitive to pressure changes with Apap which was causing arousals and leaks so aftera few months of experimenting and guidance here we settled on straight pressure of 12cms, titration was 13cm but he could never tolerate it. That solved the problem and he slept on Cpap for over a year. I experimented with Apap again about 6months ago and he did well at 10.5-13 with the same good results(90% 11-12),AHI always under 2. Just before Xmas he began to exhibit daytime sleepiness and other pre-cpap symptoms again but with no change in data results. I changed his pressure back to Cpap at 12cms last week and he seems better now. So that was important information for me to know. Apap is invaluable for these in-home titrations to make sure you're on track and to monitor any changes. I'm glad I have an Apap even if I rarely use it.

Very curious Dori and it seems to beg a question that has been on my mind. I wonder if certain people need to CHANGE their therapy ever so often to get better results. Right now I have been on CPAP for 2 months (after APAP for 2 months) and it seems I am getting progressiely more tired to the point that it hardly seems worth the trouble to hook up the machine. I really need to switch back to APAP or maybe even VPAP not sure but my titrated pressure or 11 - 12 roughly is not cutting it on CPAP AND like you mention my numbers are still showing good, I just dont feel good.

[tschultz]

From everything I have gathered it seems that APAP is best used over a narrow range, closely matched to what you would use for CPAP, this permits minor changes due to congestion, position, or other factors. For some however the pressure changes due cause arousal and for these straight CPAP is preferred, I suspect these same people may have problems with machines using exhalation relief where pressure is reduced slightly during exhale. I see in many cases people run straight CPAP mode, monitoring data and then periodically may run APAP mode to determine if the optimal setting for CPAP should be "tweaked".

Having spent my first night with the ResMed S9 with EPR on full, I can see the advantage as compared to straight CPAP thinking back to my sleep study for CPAP titration where it was more difficult to exhale. I can also see however where it may be distracting/irritating for some. I can only imagine the impact of BiPAP with a greater pressure difference but am sure that too has its downside for some people.

[DoriC]

tschultz, You bring up a good point. We also found out pretty quickly that flex was incompatible with Mike's breathing pattern. He complained that the machine was "rushing" him to breathe before he had completely exhaled, so I was able to observe that his inhale is rather short but he has a longer,deeper exhale. (I spent a lot of time hovering over him while he slept as you can see!) We turned flex off and that problem was solved. I fought a good battle with the DME for the auto with all the bells and whistles only to find that he does best with straight cpap,no ramp, no flex,no humidity(just passover)! Go figure!

[rested gal]

We also found out pretty quickly that flex was incompatible with Mike's breathing pattern. He complained that the machine was "rushing" him to breathe before he had completely exhaled, so I was able to observe that his inhale is rather short but he has a longer,deeper exhale. (I spent a lot of time hovering over him while he slept as you can see!) We turned flex off and that problem was solved.

Wouldn't have mattered even if he had had a very short duration of breathing out. C-Flex is always going to bring back in the regular pressure before an exhalation is finished. Short or long exhalation, that's going to happen with C-Flex because that's the way Respironics' C-Flex is deliberately designed to work.

ResMed's EPR, on the other hand, like what tschultz is using, doesn't do that. EPR keeps the pressure down even after the exhalation is finished unless the exhalation goes on and on and on much longer than most people would ever breathe out...or longer than anyone would pause after exhaling before they started to inhale. EPR keeps it down until the person starts to breathe in again....unless the person doesn't start breathing in again within a certain number of seconds from the time they started exhaling.

You bring up a good point, though, Dori. Some people don't do well with C-Flex turned on, although many find it makes treatment more comfortable. For those who don't do well with it, it definitely can make it feel like the machine is pushing them to breathe in before they are finished breathing out.

Mike is so fortunate that you took (and always will) an interest in making his therapy as comfortable and effective as possible for him!

Cflex 1-3 Levels - topic started by jucs
January 2, 2010
viewtopic.php?p=436272#p436272

Although that topic was about C-Flex in a Respironics machine, my replies in that thread also talk about EPR used by ResMed machines. C-Flex and EPR are both features to give some relief from pressure when a person is breathing out. But they go about it in very different ways from each other.

[robysue]

ResMed's EPR, on the other hand, like what tschultz is using, doesn't do that. EPR keeps the pressure down even after the exhalation is finished unless the exhalation goes on and on and on much longer than most people would ever breathe out...or longer than anyone would pause after exhaling before they started to inhale. EPR keeps it down until the person starts to breathe in again....unless the person doesn't start breathing in again within a certain number of seconds from the time they started exhaling.

I know that's what the ResMed literature says.

But that's sure not the way my S9 AutoSet felt when I was using it in straight CPAP at 9cm with EPR = 3 and when I was using the S9 in APAP mode running in a tight range of 7--8cm with EPR = 2. The whole time I was using the S9, I felt like it was rushing me to inhale before I was ready by forcing additional air down my throat during the latter part of my exhale. (In APAP at 7--8cm, the rushed breathing feeling was worse with EPR set to 3 than EPR set to 2; in CPAP at 9cm I simply could not exhale with EPR set to 2.)

And I feel I can finish my entire exhale with my BiPAP set at 8/6 with Bi-Flex turned OFF. It is a great relief.

[rested gal]

Back in this thread:
viewtopic.php?p=552899#p552899

In retrospect, what I noticed with EPR was that while the pressure drops at the START of the exhale, it also INCREASES during the SECOND half of the exhale phase of each breath. And that increase in pressure while I was still exhaling tickled the back of my throat during every single breath! Really, really bad. Drove me bananas. And I couldn't explain it.

I have absolutely no doubt you sensed that, robysue. However, unlike C-Flex/A-Flex, Resmed's EPR is not designed to increase pressure during exhalation. Rather, Resmed's EPR is designed to increase pressure when positive flow (inhalation) is detected---in the same way that Resmed BiLevel/VPAP does. So I'm thinking when that throat-tickling happened to you, either your breathing pattern fooled EPR to prematurely trigger to inhale pressure, or those pressure increases that tickled your throat were the central-apnea sensing FOT signals.

BTW, excessive, brief leak spikes can prematurely trigger IPAP---as they look like the start of positive/machine-outbound flow to a sensor. Also, expiratory pauses with a brief inhale "hitch" or false start---before true inspiration---can prematurely trigger IPAP. Anyway, the EPR=3 diagram below helps us to see that EPR is designed to commence the rise to inhale pressure when positive patient flow gets started after that post-expiratory pause. Again, if the post-expiratory pause is long, then FOT detection oscillations might kick in and "tickle".
http://www.internetage.ws/cpapdata/resm ... ochure.pdf
https://www.cpap.com/DisplayNewsletter/ ... ue-19.html

Like -SWS, I have no doubt that you felt pressure increase, Robysue. Most likely from one or more of the causes -SWS described perfectly.

That's why it's good that different brands have different ways of going about what they do -- and different models of machines within a brand -- and all of them can do straight CPAP if that works best. Can take some trial and error to find what works best for any given individual.

Glad you've found the machine and operating mode that works best for you, Robysue! Had to be frustrating "getting there", but it's paying off for you now.

[jnk]

I think it can help how EPR feels for some if, in CPAP mode anyway, the EPR Inhale is set to Medium instead of Fast. I'm not sure that adjustment is available in Auto mode in the S9 Autoset, though. I forget.

True bilevel probably feels different from simulated bilevel, so I assume Robysue's statements are more about how bilevel feels compared to nonbilevel than about how ResMed feels compared to Respironics. She can only compare what she has experienced, as far as how it feels, I assume, which makes her statements comparing two very different kinds of machines seem to say things I don't think she intends to be saying. Then again, I may be misunderstanding things myself.

The whole "flex" thing gets VERY confusing to me, since it seems to mean something completely different in a Respironics bilevel as compared to a Respironics CPAP/APAP. Biflex, as I understand it, sort of rounds the edges of the bilevel pressure curve, whereas the CPAP versions of "flex" are about actual exhale pressure relief at the start of exhale. Right? Or am I confused on that?

All I know is that for me, any time comfort-setting discussions mix with bilevel-vs-CPAP discussions, the waters get pretty muddy rather quickly, since, to my way of thinking, ResMed is actually trying to simulate bilevel with one of its comfort settings (EPR). I'm not saying it is a good thing or a bad thing, I'm just saying it is confusing to find a way to discuss it with clarity sometimes. I guess the plus side of ResMed's EPR is that it allows CPAPers to experience something close to (though not quite the same as) bilevel. But then the minus side could be that EPR may be more likely to impact the effectiveness of a person's therapy, since delivered pressure during exhale is affected for a longer duration, compared to the flex approach.

That is my conclusion based on my assumptions as a lay person, anyway.

Very interesting discussion from all, I think.

[robysue]

True bilevel probably feels different from simulated bilevel, so I assume Robysue's statements are more about how a bilevel feels compared to nonbilevel than about how ResMed feels compared to Respironics.

This is indeed the point to my post(s): There is a REAL noticeable difference between how a real bi-level machine works and a regular old CPAP/APAP with exhale relief works; and that difference does have implications in how some users (including me) will perceive how the TYPES of machines feel---even at LOW pressures. It doesn't matter what you call the exhale relief and it doesn't matter what the fine details of the exhale relief algorithm are, the fact remains: a CPAP/APAP with exhale relief is not the same as a real bi-level---even at low pressures and even when the difference between IPAP and EPAP is modest, as in my case.

Would I have prefered a ResMed S9 AutoSet running at 7--8 cm with EPR = 2 over a PR System One Auto running at 7--8 cm with A-Flex = 2? Would I have done any better on a PR System One Auto with A-Flex than my failure with the ResMed S9 AutoSet?

I have no idea if I would have liked the PR S1 Auto any better or worse having not used it. Given the particular kinds of problems I had with CPAP/APAP, I seriously doubt they were tied to the S9 and it's EPR algorithm. My guess is I would have had the same kinds of failures with the PR S1 Auto as well. And this was never the point of my post any way.

I do know that there is a very real difference between the way the S9 AutoSet running at 8 cm with EPR = 2 feels compared to the PR System One BiPAP running at 8/6 with Bi-Flex turned OFF. And I think the difference has to be attributed to the fact that the S9 AutoSet is NOT a true bi-level machine. No matter how that EPR algorithm works, with the set pressure = 8cm, EPR = 2, and the implication being that EPR makes the temporary relief pressure go down to 6cm on (or through) exhale, my personal experience is that the rise back up to 8cm is both qualitatively and quantitatively very different than a real bi-level machine's change in pressure from 6cm on exhale to 8cm on inhale. And such an observation shouldn't be a shocking surprise: After all, the S9 AutoSet is NOT a true bi-level machine and it shouldn't (in all fairness) be compared to one.

[-SWS]

Above we can see Resmed's graphical representation of EPR set at 3cm pressure relief. It transitions as Resmed BiLevel transitions. I drew some colorful lines in that diagram that we can use for reference.

C-Flex and A-Flex are back up to full inspiratory pressure BEFORE that vertical blue line occurs. We can see that Resmed's EPR/VPAP barely BEGINS inhale pressure's rise where I drew that vertical red line. If Resmed's transition is uncomfortable to Robysue, then perhaps she subjectively prefers that the inhale-pressure transition would instead begin where that green vertical line happens to be---or perhaps her breathing pattern tricks the EPR machine into triggering prematurely as I had previously wondered.


Alternately, I had previously mentioned that long expiratory pauses can commence the FOT central-apnea detection oscillations. Below we can see that any non-apneic pause longer than 4 seconds---but right after expiration----can do just that:



Aside from the ability to suspend amidst SDB events, EPR IS true BiLevel, robysue. However, it switches to inhale according to Resmed's trigger criteria and not Respironics'.

[Muse-Inc]

...

Thanks for the charts..I thought this was how it worked. To few posting here now know about he "fast" vs "medium" ResMed settings and how it affects the 'feel' of the delivered pressure.

ResMed is ideal for my particular native breathing patterns. If they'd started me on Respironics machines that increase pressure before exhalation stops (I naturally pause after exhaling), it would have triggered my suffocation phobia (can't breath in and out, can't breathe in and out panic tear off mask hyperventilate heat flush pulse racing) in a huge way and likely made me one of the really, really challenged to acclimate to CPAP therapy.

Shame that the newly diagnosed can't trial each of the machines to find the one that most closely matches their own breathing, esp those of us who are already hypersensitive; IMHO, if they did that, it'd likely increase compliance.

[robysue]

C-Flex and A-Flex are back up to full inspiratory pressure BEFORE that vertical blue line occurs. We can see that Resmed's EPR/VPAP barely BEGINS inhale pressure's rise where I drew that vertical red line. If Resmed's transition is uncomfortable to Robysue, then perhaps she subjectively prefers that the inhale-pressure transition would instead begin where that green vertical line happens to be---or perhaps her breathing pattern tricks the EPR machine into triggering prematurely as I had previously wondered.

You nailed it -SWS: I strongly prefer for the inhale-pressure transition to start where that green vertical line happens to be. Any early than that and I still feel like I'm NOT done with my exhale and the machine is rushing me to start breathing in!

And the comment about that vertical blue line? That's exactly why I so quickly turned Bi-Flex OFF. I can't stand that tiny little increase in pressure back up to the EPAP pressure either.