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SWS,

Here is a modification to the SV design that should eliminate your worry.

Add FOT capability to the SV and just at the beginning of each inspiration cycle and before deciding if the sleeper will hit the target flow, FOT the airway & analyze the signal to determine if the airway is open to a tracked target. If yes then proceed with the mid-point decision process & act according to flow target being met.

so

1) Fot the airway early in the inspiration cycle (needs to be a very short burst)

2) If the airway splinting based on feedback from FOT meets a tracked target then allow the PS action to be evaluated as normal.

There - a free modification - just put my name on the patent as a contributor

DSM

(I am sure there are even other quick ways to confirm the level of splint)

dsm wrote:Now here is the other side of your hypothetical ...

Your hypothetical raises the issue of "is the average person capable of being trusted with setting up an SV class machine & not wreaking havoc with their airway / health" ?

Then substitute Bilevel for SV
Then substitute Auto Cpap,
Then Cpap

I'll wait for you to answer my hypothetical be fore I comment on it

Well, there is a medically proper screening question to cover this situation, Doug: "Does your VCR flash 12:00?" If the answer is yes they cannot be trusted to set up any of those machines.

Truth be told I have a hard time telling what's technically easy and what's technically challenging for the typical "non technical" person. I think I've spent too many years thinking technically. And my memory's just poor enough that I can't remember what it's like to think in a non-technical manner about technical things. Many people have a great knack for that but I do not.

What's the correct answer to your hypothetical, Doug? Can the typical person set up an SV machine? Or can the typical person self-titrate themselves at home using an SV machine?

Will the 12:00 VCR screening question come in handy for the DIY SV crowd?
.

dsm wrote:BUT, give that person a Bilevel titration and set the SV as per Respironics instructions, then set IpapMAX to 20 and then the SV will work as well as a Bilevel but tidy up any residual OSA

Curious about this one, Doug. Are you getting a significantly lower residual AHI with BiPAP AutoSV compared to the other low-AHI xPAP modalities you used (but still left you feeling tired)?

I know you got your AHI pretty low with those other modalities but still didn't feel rested. So what do you think might be getting tidied up with BiPAP AutoSV in your case? Irregular breathing (respiratory controller issues) or outstanding obstructions (now with a significantly lower residual AHI)?

-SWS wrote:

dsm wrote:BUT, give that person a Bilevel titration and set the SV as per Respironics instructions, then set IpapMAX to 20 and then the SV will work as well as a Bilevel but tidy up any residual OSA

Curious about this one, Doug. Are you getting a significantly lower residual AHI with BiPAP AutoSV compared to the other low-AHI xPAP modalities you used (but still left you feeling tired)?

I know you got your AHI pretty low with those other modalities but still didn't feel rested. So what do you think might be getting tidied up in your case? Irregular breathing (respiratory controller issues) or outstanding obstructions (now with a significantly lower residual AHI)?

-SWS wrote:Clinical acceptability is getting it under 5 with nothing more than fixed pressure. And normalcy is getting it down below 3, last I checked. That's the purpose of any OSA titration: to eliminate as many obstructive events as possible.

(I'ld love to have your source for that! Many of us have been sensing this 3 vs. 5 difference!)

dsm wrote: Please note I agree that the PS mechanism was not specifically designed to address residual OSA but to provide servo ventilation for irregular breathing. BUT that mechanism does address residual OSA (excluding an incidental air-flow block (by way of a zero airflow obstrauctive apnea - but no cpap of any sort can clear such an incidental zero-flow apnea).

-SWS wrote:If adaptive SV were a better OSA-treatment platform the two SV manufacturers would have incentive to jointly corner the OSA treatment market (the lion's share of the SDB treatment market).

If better therapy for everyone were the aim of the machine makers and the insurance companies, an AHI of 5 would not be considered clinically acceptable, split night studies would be considered malpractice (see the info about their inablilty to discover positional apnea), and bare bones cpaps without any data cpapability (or compliance only data capability) would no longer be produced.

Autos were often touted as autotitrating machines - "no need for a costly titration, set them at 4-20 and send the patient home". Many of us have discovered that sales pitch is humbug when you want to sleep well.

As I understand it, dsm is saying that once properly titrated i.e. most events solved by the Rxed pressure /pressures, the residuals - which will be lighter given the proper titration - may be better treated by the SV mechanism. I don't see what's wrong with that statement.

It's time that we the users put an end to the manufacturer induced cofusion of auto-titration (find out the pressure that will keep you from having events 90-95% of the time) and responsive pressure(supply the right pressure range to have a person sleeping quitely all night every night. They are not the same.. An automatic machine set wide to do a nightly titration study is not good - regardless of its mechanism. A machine given a limited, but flexible response range may give a person better therapy - but that range has to discoverd by a titration process - either manual by a techinician, or mechanical, by an auto titrating machine.

I want to repeat: titration and therapy are not the same thing. If I understand it correctly for a person on basic therapeutic pressure taking care of their obstructive events, an SV may be just the additional support needed to take of the residuals that come and go.

O.

-SWS wrote:

dsm wrote:BUT, give that person a Bilevel titration and set the SV as per Respironics instructions, then set IpapMAX to 20 and then the SV will work as well as a Bilevel but tidy up any residual OSA

Curious about this one, Doug. Are you getting a significantly lower residual AHI with BiPAP AutoSV compared to the other low-AHI xPAP modalities you used (but still left you feeling tired)?

I know you got your AHI pretty low with those other modalities but still didn't feel rested. So what do you think might be getting tidied up with BiPAP AutoSV in your case? Irregular breathing (respiratory controller issues) or outstanding obstructions (now with a significantly lower residual AHI)?

SWS,

Just added the Bipap Auto SV machine to the menu at the link - it actually has me down to a very low AHI.

On the surface it might provide good results but the reason I put it aside (it was new) was that original problem I complained of where the Ipap / Epap switching was so frustrating I put all the Bipaps (incl Bipap S/T & Pro II) aside.

The Bipap SV has the most tolerant cycling I have experienced from a Bipap - even better than my dear old PB330. On a par to the Vpap IIIs, better than my experience with the Vpap Adapt.

DSM

PS I am going to do another test with the Vpap Adapt & will set MinPS to 4.6 & leave EEP at 10 & try it again. 1st time I tried it I baulked at the feeling (plus had strong nasal congestion at the time).

-SWS wrote:

dsm wrote:BUT, give that person a Bilevel titration and set the SV as per Respironics instructions, then set IpapMAX to 20 and then the SV will work as well as a Bilevel but tidy up any residual OSA

Curious about this one, Doug. Are you getting a significantly lower residual AHI with BiPAP AutoSV compared to the other low-AHI xPAP modalities you used (but still left you feeling tired)?

I know you got your AHI pretty low with those other modalities but still didn't feel rested. So what do you think might be getting tidied up with BiPAP AutoSV in your case? Irregular breathing (respiratory controller issues) or outstanding obstructions (now with a significantly lower residual AHI)?

ozij wrote:Autos were often touted as autotitrating machines - "no need for a costly titration, set them at 4-20 and send the patient home". Many of us have discovered that sales pitch is humbug when you want to sleep well.

Well, here we have the manufacturers trying to increase sales with the aid of smoke-and-mirrors claims. They wish APAPs could do that. APAPs couldn't. But the smoke-and-mirrors marketing claims presumably lead to increased sales.

ozij wrote:If better therapy for everyone were the aim of the machine makers and the insurance companies..

And here we have insurance companies who want cheaper boxes out the door.

But if Adapt SV really produced better therapy for purely obstructive etiologies wouldn't there at least be some supporting medical studies to that effect? At least one? That modality has been around for a decade-and-a-half, and I can't find a single medical study or official manufacturer statement supporting that position. And if there were supporting medical studies to that effect don't you think the xPAP manufacturers would trump their APAP smoke-and-mirrors claims with the concrete SV evidence of medical studies? Manufacturers are notorious for placing flattering medical studies on their own web sites.

None claiming that SV is a better treatment for pure OSA seem to be around, ozij. Yes, I realize and even hope you will search Google Scholar. I'm hoping to find one single study to back up that kind of "tidy up superiority" claim regarding obstructions.

There seem to be plenty of studies that claim respiratory controller issues get nicely tidied up, however.

ozij wrote:I'ld love to have your source for that! Many of us have been sensing this 3 vs. 5 difference

Here. Three and under is quite normal here. Most patients here do not claim to notice much of a difference between 3 and 5. Interestingly, the ones who do notice a difference REALLY notice a difference!

What a mystery. Alpha-wave intrusions and/or excessive CAP for those who really notice that difference? Irregular breathing patterns for some? A or H as a response to some unknown stimulus in pathophysiology?

ozij wrote:As I understand it, dsm is saying that once properly titrated i.e. most events solved by the Rxed pressure /pressures, the residuals - which will be lighter given the proper titration - may be better treated by the SV mechanism. I don't see what's wrong with that statement.

It's a definite maybe. But what else might be getting "tidied up" for a guy who's wife claims he breathes way too slowly? Could it be the respiratory controller is getting compensated since that's what the machine design was optimized to do and since that's what the medical studies about SV tend to support?

And those chest pains of Banned and mask-ripping sleep sessions that Banned fixed with his ASV. Might those also be "tidied up" vanilla obstructive events as well. Wacky me. I'm thinking if there's a machine that compensates respiratory controller gain by design, and if a person feels a lot better on that machine---then they may have had "tidied up" respiratory controller issues for lack of medical studies supporting anything else---especially when the other modalities failed daytime efficacy.

My humor aside, yes, I truly think it's possible to inadvertently address obstructions with a design that has been optimized to address respiratory controller gain problems. And for a great Aussie friend of mine who has set off both wife and BiLevel low-volume alarms in the past...

dsm wrote:If asked to take a stab at what it is I'd say the positional apneas.

Doug, I think you could very well be right. It could be positional apneas getting addressed... one way or the other:

1) positional apneas being very quickly eliminated with a sudden IPAP max pressure burst, or

2) postional apneas having triggered periodic or irregular breathing, which now gets addressed for the first time using Servo Ventilation

Ooops! Sorry, Doug. I fixed those.

Great line of discussion IMO! Just to reiterate, yes I think it's possible you're tidying up obstructive events nicely. And I think you're exploring and supporting that position beautifully.

-SWS wrote:But if Adapt SV really produced better therapy for purely obstructive etiologies wouldn't there at least be some supporting medical studies to that effect? At least one?

It's no so long ago that about 15% of those diagnosed with OSA (about 30% the supposedly non-compliant, naughty, naughty, patients , to borrow a term from dsm....) were discovered to be having complex sleep apnea, and I'm wondering how many of us are really "purely obstructive". I'm not at all implying Servo Ventilation is the right therapy for the main obstructive component in a person's breathing.

-SWS wrote: What a mystery. Alpha-wave intrusions and/or excessive CAP for those who really notice that difference? Irregular breathing patterns for some? A or H as a response to some unknown stimulus in pathophysiology?

Exactly. Considering the amount of time people spend in PSG's with cpap, and the quailty of their sleep there, I think we have no way of knowing what those residual events occuring at home really are - it's almost like trying to prove the light is really off in closed fridge, by opening the door.

How are we to know how a a normal respiratory controller functions for people who

1. have obstrucitve events
2. are forced to spend much of their time at higher than normal pressure in order to avoid the airway collapse

?

O.

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SWS wrote:what else might be getting "tidied up" for a guy who's wife claims he breathes way too slowly? Could it be the respiratory controller is getting compensated since that's what the machine design was optimized to do and since that's what the medical studies about SV tend to support?

That makes sense to me.

SWS wrote:I'm thinking if there's a machine that compensates respiratory controller gain by design, and if a person feels a lot better on that machine---then they may have had "tidied up" respiratory controller issues

Exactly!

ozij wrote:I'm wondering how many of us are really "purely obstructive". I'm not at all implying Servo Ventilation is the right therapy for the main obstructive component in a person's breathing.

Exactly. In my opinion Adaptive Servo Ventilators are not the ideal treatment machines for purely obstructive Sleep Disordered Breathing. I do think the majority of SDB people are, indeed, plain vanilla OSA'ers. But there probably is a very significant number who have (at least at times) more complicated SDB that could respond to SV treatment.

ozij wrote:Considering the amount of time people spend in PSG's with cpap, and the quailty of their sleep there, I think we have no way of knowing what those residual events occuring at home really are

Good point -- especially when so many sleep labs nowadays use split studies instead of a full night for diagnostics and a separate full night for a careful titration.

On a slightly different note... on the one hand, those more complicated cases are even more likely to drop through the cracks now that Medicare's approval of portable home studies is a fait accompli. On the other hand, perhaps more people who would never agree to go to a sleep lab but will agree to a test at home in their own bed with no one "watching", will finally be tested for OSA.

For the vast majority with plain OSA, conventional cpap/bilevel/autopap would suit them much better than an SV machine, imho. As -SWS has pointed out so well, Adaptive Servo Ventilators were designed for a very specific purpose -- to deal with periodic breathing issues. They were not designed to "automatically shoot down MOST obstructive events in purely obstructive patients."

SWS wrote:If adaptive SV were a better OSA-treatment platform the two SV manufacturers would have incentive to jointly corner the OSA treatment market (the lion's share of the SDB treatment market).

Right. They would be trumpeting that to the high heavens instead of marketing those particular machines for a very specific purpose.

The closest that either of those two SV manufacturers has come to dealing with combo OSA/periodic breathing disorders where the obstructives need EPAP set higher than 10 to prevent obstructive apneas is the Respironics BiPAP Auto SV. Respironics had to play catch-up when resmed developed their original CS2 adaptive servo ventilator targeting congestive heart failure patients with Cheyne-Stokes Respiration. Now resmed is trying to play catch-up by upping the rather low EPAP limit they designed into their VPAP ASV.

Both manufacturers keep making improvements in all their machines -- not just the adaptive servo ventilators. Maybe someday there will be a magic bullet one-size-fits-all machine to treat whatever form of SDB it sees. But at present, for the vast majority out there with plain OSA (I know, ozij...that refrigerator light... loved that! ) adaptive servo ventilation would not give them as effective treatment for obstructive sleep apnea as cpap/bilevel/autopaps can. Just my non-medical opinion, of course!

Very interesting thread this is.

RG

Have we been reading the same thread

DSM

SWS,

Interesting last night.

I was aware at one point of waking (an arousal - not at all sure of the cause) possibly just a matter of rolling over onto my back, then 'puff' a burst of pressure & I immediately thought aha - a PS boost - why ? - I am familiar enough with the machine to know it decided I was not going to reach my peak-flow & boosted.

But in a couple more arousals I wondered if the same would happen but it didn't.

So I can say that apart from positional apneas, there was what might be termed a post arousal central & the machine reacted to it.

I personally find the way the machine handles pressure to be very very plesant.

DSM

(I was sleeping a bit lighter because had to get up at 4am to catch a flight oseas - am at airport now )