Resmed VPAP Adapt SV - for Central Sleep Apnea

-SWS wrote:

Resmed ASV Patent Description wrote:In some subjects, the period of unstable breathing immediately after sleep onset could be eliminated by asking the subject to remain awake for 20 minutes after applying the mask and before going to sleeps in order to minimize overbreathing immediately prior to sleep onset.

A couple thoughts from my perspective...
In their testing, was this one night only? Or repetitive nights, same person/same machine/same mask, like you would have at home? We know there is some adjustment process going during first 15 minutes or so after LC is run, which isn't noticeable on subsequent uses; and most people would not run LC nightly at home, though they may in a lab/study situation.

I pulled out my box of masks (they long outgrew the top dresser drawer ), and there is a noticeable difference in how it feels during the learn patient phase (LPP) with any mask that is not listed as compatible. As many times as I've tried, I cannot detect a difference in LPP and normal functioning with Vista, Activa, UMFF, UMnasal, but its safe to assume there is something happening even if its not redially apparent. Nothing has come close to how LLP felt when I tried it with the Swift, and I probably wouldn't have noticed the slight difference with non-compatible mask that are able to pass LC on their own if I hadn't experienced the Swift's wild LLP. When I restart with the same mask without running LC, the LPP period is much less; I even noted that with the Swift. So is their recommendation relevant to real world use or lab use? Or a little of both- needing to stay awake during LLP if you've run LC?

Thinking real world application and not having the study in front of me to critique, another thought is if the 20 minute pre-sleep application could have a calming affect & aid in putting the person in a better frame of mind for sleeping then if they didn't have a 20 minute 'meditation' period? (how active can you be on a 6 foot leash attached to the machine and a mask on your face?) What's about the worst thing you can do if you notice you're having onset centrals?-panic, because then you'll be fully awake and have to transition again and again. Could a 20 minute 'meditation' help lower severity of sleep onset/stage I transition events on its own? Was a control run using a non-ASV BiPAP or even CPAP for 20 minutes prior to sleep to see if there were any changes? Even 20 minutes on a non-ASV machine then switching to ASV for sleeping?

Another thought is how does correction of sleep overall play in & repayment of 'sleep debt'?. I know in the past, I had noticeable periodic breathing (PB) as I would get close to falling asleep, which we know continued throughout the night. Remember how I use to say it wasn't worth it to fall asleep without my BiPAP ST because non-treatment sleep basically equaled negative sleep time, leaving me feeling worse then if I hadn't slept at all? Now, even without my Adapt, I can take a short nap or even sleep through the night (not on purpose...its just I fall asleep much faster then I was use to), with out severe PB. When I fall asleep now, I stay asleep instead of waking up constantly; its even easier to fall back to sleep on those rare occasions I do wake up during the night now. I may have some very mild PB now, or it may just be normal variations in breathing with transition into sleep- I don't have a good concept of what 'normal' is since I never really experienced it before. The only time I notice a significant increase in pre-sleep PB recently is when I'm extremely tired & exhausted or related to my allergies (when I was off my allergy meds for testing or if I had a significant allergic reaction close to bed time). Putting aside the allergy issues, I think it is significant that use of the Adapt has affected my breathing & sleep even when I'm not using it. They were not kidding when they gave it the marketing tag line of "Simply Amazing" in my experience.

-SWS wrote: Well, you can't find unicorns if you're looking for a stampede. Similarly you can't find central hypopneas if you're looking only above the frank threshold of central cascade (a.k.a. "the stampede").

So that was my problem...I always wonder why I couldn't get the license plate on the truck that ran me over at night, but it wasn't a truck at all...it was a stampede of unicorns!

Lubman wrote:My CSDB has no Stage IV and virtually no Stage III or REM sleep stages.

Do you mean you had no stage III/IV sleep or no signs of CSDB in stage III/IV? Was it 2 separate nights of PSG or a split night? Was there improvement in sleep stages with Adapt+EERS?

If the Adapt algorithm was not quite the answer for me, without EERS.
Why the ability of the ResMed algorithm to cope with my arousals better
by adding CO2 under the MD controlled conditions of EERS?

One thing to consider with EERS is there haven't been any long term studies of how well it works in the real world. Its one thing to control it a lab, where strapping on a mask a little tighter for a night or two is more acceptable then wearing that same mask as tightly at home. I hope we see the real world aspects addressed in future research, including longer term studies. One leak and you've lost all the benefits and it almost seems like you could be worse off if your CO2 levels are bouncing around in a wider range.

What was causing the arousals? Is the EERS treating a symptom of something else or actually attacking the root cause? Did they test you with EERS on other types of machines or only with Adapt? Could have the EERS+some other xPAP have helped as much, if not more? If it was a split night study, would of you had less events towards morning anyways? Mine always went down, since centrals don't occur during REM generally and by nature, we tend to have more REM in the second half the night. Just some thoughts that come to mind...

a) why the machine only recommends certain masks, because the feedback loop from the pressure sensor tubing, has been "corrected" or "compensated" for only a few mask models.

Its not just that the mask can pass LC on its own, but the algorithm has the masks' vent projected leak rate at every pressure, which is part of its calculations. Using a mask that's similar to one of the listed ResMed masks and that can pass LC may work for the most part, but there is always the chance it won't. Kind of like when you go to England...they may speak English, as do we (sort of), but things still get lost in translation occasionally. Over time, it may change as firm ware updates become available. One thing I wish ResMed would address is if there are any significant firmware updates, if they will make it easy for our machines to be updated, since the manual states it doesn't need any general/preventative servicing for 5 years.

b) And with a well fitted mask, and a patient in the lateral position (where leaks seem more likely to occur with a moderately well fitted mask that was adjusted to a sitting or supline oriented person), would be more critical to proper machine operation.

That recommendation for sleeping on your side still seems odd in relation to central events or CSDB, since they are by nature not positional as obstructive events tend to be. It would be interesting to know the reasoning behind them recommending that.

It's as if the ASV solution works when the environment is as close to ideal as possible. E.g., the mask volume is known, the vent holes are placed for the proper washout (or controlled washout) of CO2, and it doesn't leak or the leak rate is constant where the machine can compensate or partially compensate for the leak

The constraints of the Adapt are not for everyone, that's for sure, especially compared to most other xPAPs that can use any mask, any hose, etc. The benefits far outweigh the limitations in mask for me. It is one of the few times were the 'machine fit with person' is more critical then having the most comfortable mask possible.

CQ

Thank you for the comments from my last post.

Lubman wrote:
My CSDB has no Stage IV and virtually no Stage III or REM sleep stages.

Do you mean you had no stage III/IV sleep or no signs of CSDB in stage III/IV? Was it 2 separate nights of PSG or a split night? Was there improvement in sleep stages with Adapt+EERS?

I mean I don't generally have any Stage III, Stage IV or REM sleep stages in most of my PSG's. In a quick review of past studies I have never had any REM sleep recorded except for a brief few minutes in the last ASV based study.

You make a good point, EERS with some other device may have also been effective. I did not have a multi night test - simply a split night study, and much of it on ASV due to the sharp drop in OX Sat when not on any treatment.

Lubman

Resmed ASV Patent Description wrote:
In some subjects, the period of unstable breathing immediately after sleep onset could be eliminated by asking the subject to remain awake for 20 minutes after applying the mask and before going to sleeps in order to minimize overbreathing immediately prior to sleep onset.

I didn't think the idea was for a patient to remain awake for 20 minutes after the first initiation of ASV therapy. ResMed recommended that a patients BP was to be taken in a supine position. Then they were fitted with a full face mask. Then therapy was started and BP was checked again in 5 minutes. After 20 minutes BP was taken again. Therapy was stopped and again in 5 minutes BP was taken. If anyone had systolic below 80 then the MD was told to watch the patient and consider discontinuing the treatment.

After that I have never heard of the keep patient awake comment.

Some of the initial literature said that one should wait 40 minutes for CSA or any vocal cord closures caused by hypocapnia to be resolved. After the 40 minutes EEP could be increased.

Christine thanks for your intro and info on Friday. Sorry it took so long to respond. I've snipped from your message and commented in bold.

I'm glad you joined us Bella...and for everyone else, Bella & I got to know each other on a non-sleep related board a couple years ago and then she got DXed with CSA. Talk about strange coincidences.

And yes, in answer to your PM, we need to find out if the Adapt is available in Canada yet...or even the Respironics ASV, which was just approved in the US & isn't on the market yet.

According to the Respironics (US) announcement for its “BiPAP autoSV”, it was launched in Europe and Canada prior to US release, but I couldn't find anything on ResMed either.

My first PSG stated that - only 1 minute of deep slow wave sleep was noted and no REM sleep or stage 3 or 4 sleep. I just noticed that in my first study that my events were severely elevated at the beginning of the study, and in the second study I didn’t have any REM sleep until I was asleep for almost 5 hours (practically the whole study time). I’ve been waking up a lot in the early part of the night, but sleeping pretty soundly at the back end. I wonder if that means that my settings aren’t as effective anymore and I’m reverting to pre-bipap behaviour. I think I’m treading water too Christine.

Did the DME you obtained your Synchrony from also carry ResMed machines?

I’m not sure. I got mine through a provincial program and I don’t know if they carry all brands. But the DME who was the go-between seems to carry mostly Respironics machines (according to their website) and the RT told me that the supply a lot of the equipment to the provincial pool.

I want to call them and ask about a machine like yours. I’ll just keep saying to myself “ResMed VPAP Adapt SV (US name) or the AutoSet CS2”. But, in addition to being tired from a variety of things, I’m shy and a procrastinator.

RG – thanks for the link and DSM – thanks for your input too. I’ve been following this thread, and while I have to admit that some of the techie stuff has been way over my head, it sounds like the ResMed machine is more effective. Christine has made it sound better than “the best thing since sliced bread”.

A last question – the type of mask used seems to be pretty important. I got an F&P 432 FF mask a few months ago and I love it. It actually seals! No leaks even at a pressure of 14. I read your recent message about mask types and I wonder if its specs match the UMFF if it might work ok too.

Thanks everyone - and if I'm not posting I am indeed reading!

Bella wrote: I’ve been waking up a lot in the early part of the night, but sleeping pretty soundly at the back end. I wonder if that means that my settings aren’t as effective anymore and I’m reverting to pre-bipap behaviour.

Looking back at all my PSGs, I can tell the difference when they let me sleep as long as possible or not affected how much Stage 3/4 & REM I had (they let me sleep 10 hours for my first one). The first part of the night was always the roughest for me for years, pre-BiPAP & with BiPAP ST. Getting to sleep and staying asleep isn't easy when you keep having central events that pull you out of sleep and have to restart the transitioning process all over, again & again. When they did the split night study last fall, it really showed how bad it was without BiPAP ST...and why I had such good compliance, since 'sleeping' without it wasn't much of an option (even if sleeping with it wasn't that great of sleep either).

I remember feeling if only I could get to the second half of the night, where I slept more soundly, without 2-3 hours or more of bouncing in and out of fairly light sleep, it would be so much better. I have to tell you, I don't miss it at all. I don't miss that early morning sleep being so hard that if I was awakened from it, being so out of it. It use to feel like my body just shut down, out of shear exhaustion from the lack of quality, restorative sleep. Those couple hours couldn't make up for an entire nights sleep, but they did get me by...if only barely. I don't know if you ever have a night were do get to sleep fairly easily and stay asleep now, but I use to have one every 7-10 days or so. I could never figure out what I did differently to sleep so much better, other then exhaustion. I didn't have more energy the day after, in fact, that would usually be the start of a day were I slept 16-18+ hours in a 24 hour period.

Its not that everything is perfect now by any means, I still have days were I'm tired or nights were its harder to fall sleep and my sleep still gets disrupted because of my other medical problems at times. But now the ups & down seem to be closer to what most people would consider normal. Sleep is no longer such a big part of my life, wondering every night if I'll get to sleep and stay asleep or will I be half awake all night, which left me feeling half asleep all day.

Bella wrote: RG – thanks for the link and DSM – thanks for your input too. I’ve been following this thread, and while I have to admit that some of the techie stuff has been way over my head, it sounds like the ResMed machine is more effective. Christine has made it sound better than “the best thing since sliced bread”.

The Adapt is great, and knowing how similar our medical situations are overall, I can't imagine you not doing better with it then BiPAP ST. Its a wonderful machine for those of use who have severe central disorders, but I don't know how effective it would be is someone only has minimal centrals or none at all.

I think its time to set up an appointment with your sleep doctor to see what is available to you and what steps you'll need to take to get a trial with an Adapt. The good thing is, at least in the US, its classified the same as BiPAP ST, so I would think the same program would still cover it that paid for your Synchrony.

Bella wrote: A last question – the type of mask used seems to be pretty important. I got an F&P 432 FF mask a few months ago and I love it. It actually seals! No leaks even at a pressure of 14. I read your recent message about mask types and I wonder if its specs match the UMFF if it might work ok too.

You might be surprise how well the ResMed masks work for you with the Adapt. You could always try the F&P FFM and see how it feels, but I would recommend using one of the listed masks if you can. The F&P FFM is not as likely to have issues like the Swift did, but now that I'm aware of the machine learning patient process that runs anytime the Learn Circuit has been done, I can feel a difference when I use other brands mask. I tried a Respironics ComfortFull FFM the other day, which fits me better then the ResMed UMFF, but I haven't tried for a full night yet. I had used some other nasal masks early on that passed LC fine, but I don't know if I'll be using them much in the future now.

Lubman wrote:

Resmed ASV Patent Description wrote:
In some subjects, the period of unstable breathing immediately after sleep onset could be eliminated by asking the subject to remain awake for 20 minutes after applying the mask and before going to sleeps in order to minimize overbreathing immediately prior to sleep onset.

I didn't think the idea was for a patient to remain awake for 20 minutes after the first initiation of ASV therapy. ResMed recommended that a patients BP was to be taken in a supine position.

Resmed's above recommendation to "remain awake for 20 minutes after applying the mask" is an excerpt from the 2003 U.S. patent description. It's the very last paragraph and sentence of text on that patent description.

However, I have absolutely no clue about any of the underlying details that went into that recommendation. My assumption is that Resmed suggests experimentally applying the mask with ASV pressure therapy engaged versus off. However, Resmed does clearly state in their recommendation above that a patient should remain awake for twenty minutes after applying the mask (if attempting this transitional experiment). But if this suggestion in the patent description isn't embodied in current field practices or manuals, then perhaps the advice is no longer considered valid or prudent.

In my opinion the advice may hint at underlying homeostatic transition (if not entirely anxiety-based transition) even more than machine-based or algorithmic adaptation. Yet this transitional machine-induced overbreathing tendency may actually be a combination of those same two interrelated factors: patient over-reacting to machine pressure, and machine adaptation phase thus initially dramatically overshooting and undershooting (even more than usual as it calculates a ventilatory fix).

I entirely agree that Resmed is talking about a unique subset of ASV patients with this advice.

In some subjects, the period of unstable breathing immediately after sleep onset could be eliminated by asking the subject to remain awake for 20 minutes after applying the mask and before going to sleep in order to minimize overbreathing immediately prior to sleep onset.

Since the discussion immediately preceding that line is referring to the acute appearance of significant hypocapnia:

In most subjects, transcutaneous PCO2 fell by approximately 5-10 mmHg due to a period of hyperventilation in the first minutes of awake breathing. This resulted in some instability of the upper airway and residual Cheyne-Stokes breathing for the first 20-40 minutes of sleep.

it seems pretty clear to me that they're referring to an inappropriate entry of the Auto CS into ASV Mode, which, of the terms that I have used to describe this (Patient Asynchrony and runaway), "runaway" seems most appropriate.

Lubman wrote:After that I have never heard of the keep patient awake comment.

Maybe not in so many words, but back on September 2, 2006, we said here that

I'm sticking with runaways as the chief cause of ASV failure, and that arousals and awakenings cause/contribute to them. Usually we think of respiratory events causing disturbances, but in this case, I'm thinking that Adapt SV has a dog of a time trying to adjust to very light NREM sleep transition state (Wake/Stage 1). The physiological changes that occur between Wake and Stage 1 are huge, including such factors as baseline minute ventilation, the loss of airway control and central apnea threshold. Large changes in minute ventilation can (maybe "will") result in a runaway (however long or brief).

and there's no real good way to work

Y'know, every now and then this thing has a runaway that could make things worse before they get better.

into the sales pitch.
SAG

[quote="christinequilts
The first part of the night was always the roughest for me for years, pre-BiPAP & with BiPAP ST. Getting to sleep and staying asleep isn't easy when you keep having central events that pull you out of sleep and have to restart the transitioning process all over, again & again. When they did the split night study last fall, it really showed how bad it was without BiPAP ST...and why I had such good compliance, since 'sleeping' without it wasn't much of an option (even if sleeping with it wasn't that great of sleep either).

I remember feeling if only I could get to the second half of the night, where I slept more soundly, without 2-3 hours or more of bouncing in and out of fairly light sleep, it would be so much better. I have to tell you, I don't miss it at all. I don't miss that early morning sleep being so hard that if I was awakened from it, being so out of it. It use to feel like my body just shut down, out of shear exhaustion from the lack of quality, restorative sleep. Those couple hours couldn't make up for an entire nights sleep, but they did get me by...if only barely. I don't know if you ever have a night were do get to sleep fairly easily and stay asleep now, but I use to have one every 7-10 days or so. I could never figure out what I did differently to sleep so much better, other then exhaustion. I didn't have more energy the day after, in fact, that would usually be the start of a day were I slept 16-18+ hours in a 24 hour period.

Bingo - that's how I feel. The other day I either slept through my alarm, or woke and went right back to sleep and my husband had to come and wake me. Every week, as I get closer to the end of the work week, I get more tired. I've cut back to four days now.

You might be surprise how well the ResMed masks work for you with the Adapt. You could always try the F&P FFM and see how it feels, but I would recommend using one of the listed masks if you can. The F&P FFM is not as likely to have issues like the Swift did, but now that I'm aware of the machine learning patient process that runs anytime the Learn Circuit has been done, I can feel a difference when I use other brands mask. I tried a Respironics ComfortFull FFM the other day, which fits me better then the ResMed UMFF, but I haven't tried for a full night yet. I had used some other nasal masks early on that passed LC fine, but I don't know if I'll be using them much in the future now.

When I first was starting up I tried all sorts of masks at the DME. I did try the UMFF and almost bought it. And then the RT had my try tossing and turning and sleeping on my side (which I don't do) and I felt that the cross-piece on the forehead dug in. I got the Comfortfull and I have had so much problems with leakage. I tried moleskin, tightening, loosening the straps etc. After about a month I went to the Swift, and when after a number of months when it started to irritate me I went back to the Comfortfull. It behaved for a couple of weeks and then for who know what reason, the "elephant trumpeting" started again. That's when I got the F&P432 and it seems to seal well around my slightly out of line jaw.

Bella

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CPAPopedia Keywords Contained In This Post (Click For Definition): respironics, resmed, bipap, swift[/quote]

StillAnotherGuest wrote:it seems pretty clear to me that they're referring to an inappropriate entry of the Auto CS into ASV Mode.

Yes, I agree this is very obviously a case of patient-and-machine asynchrony. But this is also a case of two-way maladaptation.

Think of two oncoming strangers awkwardly passing each other in a shopping aisle. They ineptly fail to sidestep each other again and again, as they simultaneously jockey back and forth. Finally, after ten maladaptive attempts, they both laugh in embarrassment before correctly sidestepping each other. SAG, can you tell me precisely which of those two strangers initiated the maladaptive process at an "inappropriate" moment? Both? Neither? The first shopper? The second shopper?

I can't say in my own mind that the ASV algorithm clearly entered ASV mode at an inappropriate time. Rather, I think as soon as the mask is applied the ASV machine enters what Resmed calls "adaptation mode" in all cases. And this two-way response and counter-response type negotiation clearly becomes a two-way maladaptation process.

Just because the patient's overbreathing entails hypocapnia, does not pin down the two-way maladaptation process to inappropriately timed ASV mode. Yes, acute hyperventilation entails hypocapnia. But that alone is not sufficient basis to pin down this two-way maladaptation to inappropriately-timed ASV mode. The hypocapnia clearly results from hyperventilation. And hyperventilation is clearly a case of overventilation. But ventilation and quite possibly over-ventilation in this case is a combined effort. Which maladaptive shopper initially compensated incorrectly? Which ventilatory contributor initially maladaptively over-ventilated here? Was the patient maladaptively overbreathing in response to the machine? Was the machine maladaptively over-ventilating in response to the patient? Or did they both simultaneously contribute to a two-way maladaptation just as those awkward shoppers did?

You can hyperventilate down at the grocery store and have significant hypocapnia. Alternately, some of these patients find themselves on ASV because their own physiology tends to maladapt to traditional xPAP platforms. Hypocapnia alone is not sufficient basis to determine that the ASV machine entered ASV mode at an inappropriate time in my opinion. Rather the ASV machine immediately enters adaptation mode in all cases. I'm still sticking with my original opinion on this one (not to say that I'm guaranteed to be right ).



Theoretical Thought for the Day: At one or multiple points in evolutionary history various functionally-rigid and neurologically-based homeostasis processes were likely augmented by neurologically-based adaptive plasticity. Greater adaptive flexibility theoretically entails significantly enhanced chances for individual and thus genetic survival. This theory attributes a functionally-rigid and lower-order homeostasis as being the evolutionary basis for a more functionally flexible set of problem-solving circuitry: neural adaptive plasticity. Here survival-based problems presented to central physiology are the immediate and extended-term problems being neurologically solved. Since higher intelligence is also all about neurologically-based problem solving, intelligence itself may also have its evolutionary roots in lower-order homeostasis (perhaps even cellular). Problem solving itself may be attributed to immediate and recurring survival of threats, subsequent genetic propagation, and thus species survival and even evolution.

However, personality is also based in neurology. And personality just may be a case of socially-driven adaptive problem solving as well. Personality affects not only our chances of collaboratively surviving within our social species, but personality also affects our chances of propagating our DNA to subsequent generations of our species. As with higher intelligence, socially-adaptive personality may even have its evolutionary roots in lower-order homeostasis.



But back to machine-triggered central maladaptation in general. I think there is a caveat of attempting to reduce machine-triggered central maladaptation to overly-narrow blood-gas-related considerations---as if machine-induced maladaptation were universal in pathology and solely related to basic ventilation and overventilation issues. But I've always been a strange thinker. .

-SWS wrote:SAG, can you tell me precisely which of those two strangers initiated the maladaptive process at an "inappropriate" moment? Both? Neither? The first shopper? The second shopper?

Sure. It was initiated by the former (the patient) and perpetuated by the latter (the machine).

Here is an example of this phenomenon, a patient-generated "runaway" at the introduction of AdaptSV:



This is a patient whose baseline minute ventilation (MV) should be about 5 L/min. A brief period of hyperpnea at application of AdaptSV establishes a Target greater than need, or about 7.5 L/min. While Target is rapidly increased based on MV (otherwise it couldn't attack a central apnea, it has to do so within a couple of breaths), the decay of the curve is very gradual as the machine reduces Target based on 90% of recent ventilation (and which is machine-generated MV. The patient has to sit there, being "pushed' by the machine, waiting for the successive 90% of MV Targets to drop back to his own MV, whereupon he can take over again). In this case, the process takes about 10 minutes.

While you're down at the market, can you grab a bag of cotton balls for me? Pay you when you get back, I'm out of diffuser pads.

Hey, it could have been worse.
SAG

a patient-generated "runaway" at the introduction of AdaptSV:

So let me see if I have this right:
I start using the ASV at the beginning of the night, and it is doing the "learn patient" , and it is not letting me breathe as slowly as I normally would, which is what I have called "uncomfortable." I can feel the IPAP starting up before I am finished with the exhale. And what I have done is wait through this, it takes about 20 min I think....Which sounds like what I am supposed to do...
I had been thinking that was the expiratory end pressure I was feeling, and thought it was normal. But actually it was the forced backup rate kicking in. The EEP does not function until it is in ASV mode in response to problem breathing patterns if they occur during sleep.
Now, if I am right so far, the next piece goes: If it is doing this backup inappriopriately for me, forcing more frequent breaths, wouldn't my MV be reduced? If so, that would have an effect on the algorithm seemingly opposite from your example of a runaway, so it is not a runaway situation.
That would be more when I wake in the middle of the night with the machine doing a clear runaway - much larger volumes being moved and I think a higher pressure also involved.
Getting back to what I would call in VPAP III bipap terminology a too short IPAP MAX during the learn patient, and here's the main question: the consensus here is that is occurring due to the use of the Swift, and/or the nonvented EERS configuration with the Swift.
Do I have this right?

I still have yet to experiment and report back on Vista vs Swift (both nonvented/EERS setup) - will do soon.

frequenseeker

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StillAnotherGuest wrote:Sure. It was initiated by the former (the patient) and perpetuated by the latter (the machine).

My rhetorical question really went toward those two shoppers to demonstrate an underlying point: the maladaptation is two way and thus simultaneously perpetuated by both.

If any patient is inclined to physiologically maladapt to pressure-based xPAP therapy, then I'm not at all surprised to hear that this patient took the first maladaptive step. In a simultaneous and two-way perpetuated maladaptation scenario, the nature of the problem is not at all defined by who took the first step. Rather the nature of the problem is defined by a short-term impasse being simultaneous and two-way perpetuated. Eventually one or both players adapt to transcend that two-way perpetuation. And even that last statement doesn't define the salient nature of the two-way maladaptation problem: it defines the nature of the resolution.

Hey, even those two maladaptive shoppers entailed a temporally-based first step that was not likely simultaneous. But they both simultaneously perpetuated the problem until one or both maladaptive shoppers finally reached that resolution.

I wouldn't buy any cotton balls with all those little venturis.

My brother is going into BI tomorrow for a sleep study with the Respironics vs ResMed ASV. There has been extensive discussion here about the technical differences between the two. Some of the ideas and information has shifted back and forth.. I would like to pass along the benefit of your conclusions to BI, but it is a bit confusing to me to pick through the posts.
I am wondering, could someone put together a summary of the conclusions here? Today?

Thanks and sorry for the short notice,
frequenseeker