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SWS,

As with RG, good post & well put. With the more we are all learning, I too believe the dominant concern of the APAP algorithm designers was the problem of inducing more problems than they were trying to fix if raising pressure to quickly & by too much when an individual OSA block is in progress.

The biggest concern I could read into the patents was that they didn't always know what the real cause of the block was and even an educated guess (by the algorithm) wasn't good enough to justify raising CMS during the block.

Raising pressure on someone with a central may have been the #1 concern.

DSM

PS Car rally was an excellent event - the holders have announced the next one as a drive from Albury NSW to Albany in WA - for us that is Sydney to Albury to Albany which one way about 3,000 miles (approx 4,800 kms). But with my talented wife as chauffeur we can do it

Seriously, my wife likes driving & of the 1,900 kms to Barossa & the 1,600 kms back, she drove over 90% of it.

I'll try to set up some pics of the countryside & some of the neatest looking country pubs in a photo gallery & will post a link. I had forgotten how flat much of inland Australia is

D

This discussion is very interesting. Thanks for participating.

Clearly I had apneas (very many) before cpap treatment and still have apneas (very few) with appropriate cpap treatment.

Without treatment, I had a fair amount of apneas which were circa 90 seconds. With treatment the longest apneas are circa 20 seconds.

It is no surprise that appropriate cpap treatment reduced the number of apneas. But did it reduce the length of apneas? If so, how?

-SWS wrote:That's only my opinion, guys. So please be kind or entertaining or both as you disagree with me!

You know better, -SWS. Begging for mercy is not acceptable practice here. Not here! Maybe on the ASAA forum ..., where rules ensure fair play. No wait, what happened there ... that display yesterday ... was most assuredly not fair. Just downright pitiful, IMHO. Nuff said?

-SWS wrote:But I honestly don't think the cautious pressure response relates to the cork theory.

Go ahead and make fun of my pet theory, will ya? Never mind my feelings. Hehehe, I'll bet folks remember it though ...

To summarize: According to the patent, Respironics APAP machines don't clear apneas. The intent is to be pre-emptive and prevent future apneas. Once an apnea has occurred, the machine simply waits it out, at least according to the patent.

-SWS wrote:Before going any further, I'd like to mention that the "Auto-CPAP Control Layer" contains that borrowed and significantly modified functionality from the old HealthDyne patent you cited, Bill. Interesting that in 1993 it was the heart of an APAP algorithm. Here it's the lowest-priority control layer toward determining an effective yet lowest possible "pressure holding pattern". Going from "heart of the algorithm" to eighth place on the priority list speaks of some very significant algorithmic evolution over the years IMHO.

Geez, -SWS, are you a spokesperson for Respironics? Maybe I'm just not easily impressed, or maybe I'm just simple-minded (or maybe a combination of the two). Priority layers seems like a bit of a misnomer, in my opinion. Apnea/Hypopnea layer priority is right there at the bottom in priority with the APAP layer. What's the highest priority layer? The ON/OFF layer!

From highest priority to lowest priority:
On/Off layer
Ramp layer
Flow Limitation layer
Snore layer
Large Leak layer,
Apnea/Hypopnea layer
Variable Breathing layer
APAP layer

Basically, the APAP layer still runs the machine. The priority layers may wrest control from the APAP layer, but most also pass back new parameters, such as new pressure levels, to the APAP layer for continued operation.

-SWS wrote: ... I couldn't wait for you to discover that paired A+A or H+H requirement. I was chuckling like a mischievous child as I was waiting for you to read that part.

You sand-bagger! I'm sensing a set up.

-SWS wrote:I think we all agree (and have agreed for some time) that an APAP doesn't just "pop up and readily shoot an apnea blockage down".

Great! Universal agreement ..., at least since I cited the patents.

-SWS wrote:That's only my opinion, guys. So please be kind or entertaining or both as you disagree with me! But I honestly don't think the cautious pressure response relates to the cork theory. Rather, I think it relates to pressure-related homeostatic issues that have always been present in a very significant portion of the SDB population. The patent descriptions thus all cite significant concerns about: 1) central apnea induction and 2) inadequate means of central apnea differentiation.

But I have yet to see a single patent description cite any concerns whatsoever about cork-style tongue blockages. .

Sure, go ahead and have fun at my expense. You, who just begged for mercy ... I'll still bet ya folks remember it ...

Regards,
Bill

Bill raised an interesting issue that I don't believe has been fully explored or explained here or elsewhere.

When sleepers experience an OSA block, there is a major effort by the lungs to suck in air - this effort is blocked by the collapse of the the airway through the back of the throat.

For some people, depending of throat & neck structure, the more the lungs try to suck the tighter the block gets (maybe not quite a cork in a bottle ? - but close ) - depending on the nature of the actual block, adding pressure at the external side of the block may well compound the block - but for some other people, again depending on throat structure, the added pressure may be able to pry the block open.

Is this a real scenario ?

Thus far I think it is but am willing to be convinced otherwise. Issue I see is that if this scenario is true then how would an Auto algorithm determine which type of person to apply the pressure raising approach on ?

DSM

(SWS, - my turn to chuckle )

dsm wrote:even an educated guess (by the algorithm) wasn't good enough to justify raising CMS during the block.

I've lost track of who is looking at which patent where... LOL!

For quite some years now, hasn't the REMstar Auto's algorithm raised pressure cautiously (those three pressure increments it uses to see if the airflow will improve) in the face of an apnea -- during the block?

rooster wrote:This discussion is very interesting. Thanks for participating.

You're welcome.

After analyzing patents on the cpaptalk message board for a couple of days we finally arrived at the truth of the matter friends, and we all agreed that APAP can't stop no apnea once its already done started. And while all this analyzin' was goin on we all had to get in the red VW microbus to go to that other message board over there to remedy a situation which had developed. So we all collected our wits and prepared our arguments and we all headed over there.

Now friends, there was only one or two things that Mike coulda done to us, and the first was he could have given us a medal for being so brave and honest on the forum, which wasn't very likely, and we didn't expect it, and the other thing was he could have bawled us out and told us never to be caught posting garbage on his message board again, which is what we expected, but when we got to the message board there was a third possibility that we hadn't even counted upon, and we was immediately arrested. Handcuffed. And I said "Mike, I don't think I can retract my postings with these handcuffs on." He said, "Shut up, kid. Get in the back of the patrol car." (Oops, wrong thread ... )

Regards,
Bill

NightHawkeye wrote:we all agreed that APAP can't stop no apnea once its already done started

Who is the "we" that agreed on that?

rested gal wrote:

dsm wrote:even an educated guess (by the algorithm) wasn't good enough to justify raising CMS during the block.

I've lost track of who is looking at which patent where... LOL!

For quite some years now, hasn't the REMstar Auto's algorithm raised pressure cautiously (those three pressure increments it uses to see if the airflow will improve) in the face of an apnea -- during the block?

RG,

That is part of the trap we were falling in to in looking at this in the early days. The time taken to do the 3 raises is way longer than any apnea lasts. I think in fact, that the time taken to just do the 1st pressure increment (IIRC 0.5 CMS ? or 1 CMS ?) is way longer than any normal apnea lasts. IIRC it is approx 10 secs + 10 sec wait = 20 secs & the average apnea IIRC is something like 10-15 secs (am guessing what this average is until I can dig up the data).

As we have already discussed, the technology has been there to do fast increases for quite a while. The Respironics airvalve may be the fastest adjusting device that has been used to change pressure in xPAP machines (it is used in Bipaps) & has been with us for several years now.

DSM

rested gal wrote:

NightHawkeye wrote:we all agreed that APAP can't stop no apnea once its already done started

Who is the "we" that agreed on that?

You don't agree, RG? Would you please explain your theory.

dsm wrote:I'll try to set up some pics of the countryside & some of the neatest looking country pubs in a photo gallery & will post a link.

Doug, I genuinely look forward to those pictures! Thanks in advance!

dsm wrote:Bill raised an interesting issue that I don't believe has been fully explored or explained here or elsewhere.

When sleepers experience an OSA block, there is a major effort by the lungs to suck in air - this effort is blocked by the collapse of the the airway through the back of the throat.

For some people, depending of throat & neck structure, the more the lungs try to suck the tighter the block gets (maybe not quite a cork in a bottle ? - but close Smile ) - depending on the nature of the actual block, adding pressure at the external side of the block may well compound the block - but for some other people, again depending on throat structure, the added pressure may be able to pry the block open.

Is this a real scenario ?

Let's look at that cork-theory on two bases: 1) static pressure, and 2) increasing pressure. The cork theory loses credence on all counts of static pressure since fixed pressure prescriptions anywhere between 4 or 5cm and 30 cm do not exacerbate this problem--rather they tend to fix the problem. Let's look at the transient pressure case. ASV treats cases of mixed and complex apnea, both having obstructive components. Obstructive apneic stenting exclusively via EEP does not always occur. On a regular basis across the patient population, the ASV very quickly cycles a PS increase no less than 3 cm (often plenty more). When this happens in the midst of even complete obstruction, we do not incur a cork or even super-cork problem---as strange or charmed as it may sound in physics.

rooster wrote:It is no surprise that appropriate cpap treatment reduced the number of apneas. But did it reduce the length of apneas? If so, how?

Rooster, aside from Bill's spot-on red microbus theory and his "your welcome" about your apneas, another possibility comes to mind. With CPAP pressure during an apnea your own neuromuscular effort is essentially "pressure assisted". With that pressure assistance, you require less neuromuscular effort and therefore less time to clear those residual apneas. Me thinks there are plenty of other biophysics factors at play that can conceivably influence apnea duration as well. But I don't claim to be any kind of expert, and therein lies a few dozen or hundred threads.

NightHawkeye wrote:You know better, -SWS. Begging for mercy is not acceptable practice here. Not here! Maybe on the ASAA forum ..., where rules ensure fair play. No wait, what happened there ... that display yesterday ... was most assuredly not fair. Just downright pitiful, IMHO. Nuff said?

Bill, you know perfectly well what I think of your rebellious attitude. It works very well for me. Honestly it does. It's because of spirited independent thinkers with great humor that I am here. And honestly I think you have every right to hop a red microbus and espouse your views over there. However, I also think ASAA has every right to close their doors to any red microbus convoys. And anyone here has the right to complain and protest to high heaven about that. I think both sets of rights are extremely important.

NightHawkeye wrote:Once an apnea has occurred, the machine simply waits it out, at least according to the patent.

I better not assume what others here think. But you and I seem to be in agreement that the algorithm very heavily leverages proactive pressure. We also know a very first apnea or hypopnea is cautiously discarded by the algorithm. But I disagree with you about what happens with that second apnea. If it's a moderate-to-long apnea (as quite a few are), the Remstar will begin slowly raising pressure during that second apnea rather than maintain a vigilant "hands-off/stand-back-and-let-it-clear" policy that your interpretive quote above claims.

I absolutely agree the first apnea is cautiously discarded. And I also agree that any second apnea will rarely be cleared by a slow 1cm increase. I just think all those concerns have to do with avoiding central induction. Regardless, Respironics allows up to three such pressure increases in response to apnea and/or hypopnea events before a non-responsive NR flag is set. To say that the routine is proactive of subsequent events is a true statement. To say that it is direct pressure response to detected apnea events is also a true statement. To say that Remstar sometimes raises pressure while that second apnea is happening is true as well. I'm not sure how much of this part of the discussion between you and I are wrapped up in semantics, though.

If you and I are in disagreement here, is it about concepts or semantics. Or perhaps we are in agreement? Dunno to be honest.

NightHawkeye wrote:Geez, -SWS, are you a spokesperson for Respironics? Maybe I'm just not easily impressed, or maybe I'm just simple-minded (or maybe a combination of the two). Priority layers seems like a bit of a misnomer, in my opinion. Apnea/Hypopnea layer priority is right there at the bottom in priority with the APAP layer. What's the highest priority layer? The ON/OFF layer!

From highest priority to lowest priority:
On/Off layer
Ramp layer
Flow Limitation layer
Snore layer
Large Leak layer,
Apnea/Hypopnea layer
Variable Breathing layer
APAP layer

Basically, the APAP layer still runs the machine. The priority layers may wrest control from the APAP layer, but most also pass back new parameters, such as new pressure levels, to the APAP layer for continued operation.

LOL! You are very good, Bill!!! You almost had me fooled into running out to trade a thoroughly modern Remstar Auto for a functionally near-equivalent 1993 Healthdyne machine! Let alone a 1993 machine that's missing all those higher apnea-relevant control-layers I have outlined in blue above.

Man has that bottom-rung APAP layer become functionally demoted in more than a decade or what? That APAP layer physically hosts the impeller, which is why literally everybody else on that list is allowed to run complete and unchallenged impeller-seizing roughshod over it. That APAP layer doesn't even get to vote on when or how it must relinquish control to everybody on that list as your post implies. Rather, that decision is made by Request Processor 106 on Figure 2.

Now there's a definition of centrally functional preeminence almost completely relinquished over the years if I ever saw one! But in 1993 it had central preeminence because all that blue functionality simply wasn't there! It earned preeminence by default!

Well, to answer your question, Bill, I'm not a spokesperson for Respironics. But now I must in turn ask: Geeze, NightHawkeye, are you a spokesperson for retired Healthdyne equipment?

Cheers! .

Alright, -SWS. Don't start puttin my foot in my mouth for me. I've learned how to do that well enough all by myself, thank you.

-SWS wrote:Let's look at that cork-theory on two bases: 1) static pressure, and 2) increasing pressure. The cork theory loses credence on all counts of static pressure since fixed pressure prescriptions anywhere between 4 or 5cm and 30 cm do not exacerbate this problem--rather they tend to fix the problem.

OK. Almost believable. CPAP works, right? Well, yeah, except when it doesn't ... But, hey, like I keep saying, I'm not an expert on this subject ... For that matter, I'm no expert at my own workplace either ...

-SWS wrote:Let's look at the transient pressure case. ASV treats cases of mixed and complex apnea, both having obstructive components. Obstructive apneic stenting exclusively via EEP does not always occur. On a regular basis across the patient population, the ASV very quickly cycles a PS increase no less than 3 cm (often plenty more). When this happens in the midst of even complete obstruction, we do not incur a cork or even super-cork problem---as strange or charmed as it may sound in physics.

Are you talkin to me, -SWS? Cuz I sure ain't pickin up on the acronyms. Did I mention I'm no expert ...

-SWS wrote: ... aside from Bill's spot-on red microbus theory and "your welcome" about your apneas

Hey, you took that out of context ... deliberately, I'd wager.

-SWS wrote:But I don't claim to be any kind of expert, and therein lies a few dozen or hundred threads.

Damn!!! You still need to splain the acronyms. You used 'em, you get to splain 'em.

-SWS wrote: I better not assume what others here think. But you and I seem to be in agreement that the algorithm very heavily leverages proactive pressure. We also know that first apnea or hypopnea is cautiously discarded by the algorithm. But I disagree with you about what happens with that second apnea. If it's a moderate-to-long apnea (as quite a few are), the Remstar will begin slowly raising pressure during that second apnea rather than maintain a vigilant "hands-off/stand-back-and-let-it-clear" policy that your interpretive quote above claims.

Say what??? How can you disagree with me? I never stated an opinion on what happens with that 2nd apnea. The only thing I pulled out of the patent was that the 2nd apnea has to occur before the A/H layer will even request control.

-SWS wrote:I absolutely agree the first apnea is cautiously discarded. And I also agree that any second apnea will rarely be cleared by a slow 1cm increase. I just think all those concerns have to do with avoiding central induction. Regardless, Respironics allows up to three such pressure increases in response to apnea and/or hypopnea events before a non-responsive NR flag is set. To say that it is proactive of subsequent events is a true statement. To say that it is direct pressure response to detected apnea events is also a true statement. To say that Remstar sometimes raises pressure while that second apnea is happening is true as well. I'm not sure how much of this part of the discussion between you and I are wrapped up in semantics, though.

I'm not arguing with ya!

-SWS wrote:Or perhaps we are in agreement? Dunno to be honest.

Haven't been arguing with ya.

-SWS wrote:LOL! You are very good, Bill!!! You almost had me fooled into running out to trade a thoroughly modern Remstar Auto for a functionally near-equivalent 1993 Healthdyne machine! Let alone a 1993 machine that's missing all that blue functionality

Yeah, all that blue light sounds like a real bummer.

-SWS wrote:Man has that bottom-rung APAP layer become functionally demoted in more than a decade or what? That APAP layer physically hosts the impeller, which is why literally everybody else on that list is allowed to run complete and unchallenged impeller-seizing roughshod over it. That APAP layer doesn't even get to vote on when or how it must relinquish control to everybody on that list as your post implies. Rather, that decision is made by Request Processor 106 on Figure 2.

OK. I'm convinced. I see your point. With all those other layers requesting control all the time, it's probably never used anyway. What a waste of memory to even have that damned APAP layer anymore. They should take the damn thing out for crying out loud.

-SWS wrote:NightHawkeye, are you a spokesperson for retired Healthdyne equipment?[/b]

Not unless they used to make radios.

Regards,
Bill

Bill, sorry!!!!! I regularly have difficulty gauging the correct level of humorous repartee. I have clearly done it again and I honestly didn't mean to. I thought I was being entertaining.

I will go through the acronyms tomorrow, though! Then you can see what you agree or disagree with!

Just took my melatonin...

Hmmm,

Let me revisit an old party trick but modified to make it easier to follow.

1) Boil an egg & peel it
2) Get an old glass milk bottle (large opening type)
3) Heat the bottle up with hot water then empty it
4) While still hot put the egg onto the bottle mouth
5) place the still warm bottle in a saucepan of water

What happens to the boiled egg ?

****************

a) the vacuum in the bottle could represent the breath-in effort
b) the egg could sort of represent the back of the tongue
c) the egg jammed in the bottle mouth could represent an apnea

I am not sure applying external pressure even if we anchor the egg (as the tongue is anchored), is going to clear that type of block

Only an arousal & change of body position seem likely to clear it. Also sleeping on our backs when we have OSA isn't the best for us.

DSM

-SWS wrote:Bill, sorry!!!!!

No apologies necessary. I'm not offended. I enjoyed reading and responding to your post.

-SWS wrote:Just took my melatonin...

Night, night ...

Doug, I'll trade more views on that one tomorrow as well! In the meantime, what about the missing parameter of airway elasticity (subject to inflation) in that rigid bottle analogy? What happens to that egg once even the slightest, teeniest breech in the vacuum occurs? Well, of course, it doesn't occur in your model because the neck of the bottle is rigid. But the vacuum is completely lost once the very slightest breech occurs for any reason whatsoever.

More of my silliness tomorrow...