Resmed VPAP Adapt SV - for Central Sleep Apnea

General Discussion on any topic relating to CPAP and/or Sleep Apnea.
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rested gal
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Post by rested gal » Tue Jul 25, 2006 1:04 am

Snoredog wrote:SWS wrote:
Cheyne Stokes is probably one of the easiest central-apnea breathing patterns to algorithmically recognize.
How is that? I thought that central apnea and central Hypopnea were difficult to spot on a PSG from the other thread?
my note -- The "other thread" is this one: Jun 28, 2006 subject: APNEA -v- HYPOPNEA

As a breathing pattern, Cheyne Stokes respiration is absolutely unmistakable to an observer. I can well imagine a machine design able to recognize the distinctive Cheyne Stokes cycle of increasingly deeper breaths followed by steadily diminishing shallower breaths, cessation; then starting all over again with increasingly deep breaths. It's a repetitive, predictable, pattern very obvious to the onlooker.

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medicalglossary.org

An abnormal pattern of breathing characterized by alternating periods of apnea and deep, rapid breathing. The cycle begins with slow, shallow breaths that gradually increase in depth and rate and is then followed by a period of apnea. The period of apnea can last 5 to 30 seconds, then the cycle repeats every 45 seconds to 3 minutes.
___________________________

mywhatever.com

Cheyne-Stokes respirations refer to a rhythmic change in respirations wherein breathing becomes shallower and shallower variably with a slowing in respiratory rate that culminates usually in complete cessation of breathing for several seconds to more than a minute. This is followed by progressively stronger respirations that become exaggerated and quite deep. This pattern is thought to result from abnormal brainstem responses to CO2 levels in the blood - initially undercompensating and then overcompensating.

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Dec 30, 2004 Subject: Cheyne Stokes Respiration

I think -SWS's comments about the CS 2 machine, as well as the discussion in the Apnea v Hypopnea thread is fascinating.

The earliest mentions of the CS 2 machine that I recall seeing were by a poster nicknamed "HH" on the TAS message board. I'm sure -SWS and Snoredog and ozij all remember HH's thoughtful posts fondly:

A search turned up other topics where the CS2 was mentioned, but unfortunately I can't find HH's original announcement of that machine peeking up over the horizon.

Sep 05 2004 subject: ResMed AutoSet CS2

Sep 23 2004 subject: Autopaps and CSA events

Jan 25, 2005 subject: AutoPAP and BiPAP combined topic started by WillSucceed - "Do any of you know of a machine that has autopap features (adjusts pressure as needed in response to flow limitations, etc.,) AND also has the ability to deliver a back-up rate for those people who have central apneas and need the machine to kick-in with a rate when a central occurs?"

Jul 22 2005 subject: Central Apnea/Cheyne Stokes - I'm scared topic started by Happycpaper - "I just came from my Pulmonary Specialist (sleep Doctor) and he told me that the sleep study revealed that I had Cheyne Stokes breathing, that is related to Chronic Heart Failure."

Reply by "HH": There is actually some good news on the way - it just depends on how long the FDA takes in letting it arrive.

ResMed has developed an AutoSet CS for your situation and it addresses Cheyne Stokes breathing. Information on it can be found at resmed.com.au under Clinicians.

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Post by dsm » Tue Jul 25, 2006 2:59 am

-SWS wrote:Me getting guested in the middle of an edit above.

The AutoSet CS and AutoSet CS2 context-of-use is what makes the algorithm designer's job even easier. In the AutoSet CS case, the machine was only given to CSR patients. In the AutoSet CS2 case, the CSR treatment modality is selected from the LCD panel. Once a CSR patient gets an AutoSet CS or CS2, the algorithm knows precisely what type of breathing pattern to recognize and therapeutically treat based on that context-of-use. Then the clear pattern of periodic breathing and central apneas commence as being much less algorithmically challenging than certain non-CSR SDB conditions that can be highly variable and/or highly random regarding patterns. The periodicity of CSR make for very predictable patterns of necessary ventilation. The algorithm thus proatively anticipates the next "well-timed" CSR event, versus largely having to resort to being spontaneously interpretive and thus highly reactive.



SWS
This and your earlier descriptions work for me. The CS2 docs talk of maintaining 90% repetition of the patients previous pattern sampled over a particular pre period.

After our clarifications of just what the dual-impeller blower does in the CS2 unit & looking at the very simplified diagram showing breathing with and without CS2 activated, it seems they are able to detect a declining good pattern of respiration & use the blower to gently push and pull the patient via the air circuit, into maintaining a good pattern. They seem to be able to do this with pinpoint precision in control of the airflow. Having the sensor at the mask aids them in identifying leaks vs declining breathing.

Also re detection of Apnea vs Hypop & the various forms of Hypop - if I were an xPAP machine & knowing what sensors I had & how I could interpret them, I would consider any Apnea is going to be preceded by the usual pre-symptoms such as vibrating air (pre-snoring) then the obvious serious snoring air vibrations. If I were sensing them then detected a flow-limitation within a close proximity, I would flag it as an Apnea then go into my 'Dealing with Apnea' patterns. The difficult pattern is if the sleeper changes position and that causes a sudden blockage of the air way. If the limitation was sudden & sharp I might consider it an Apnea, if there were a clear pattern of preceding flo-limitations without the side symptoms of vibrating air, I would lean to Hypop & if then a flow limitation occurred I would consider it a probable central.

But we all know that the average current machine (AUTO) is not super good at accurately pinpointing these differences when combined with mask leaks. And, that even if they (AUTOs) do detect what they think is a general hypop or a clear central hypop, they can't do a thing about it other than in the case of Bilevels, to flip between IPAP & EPAP in the hope this will trigger resumed spontaneous breathing.

The CS2 seems to be geared to understanding the normal breathing of the user & to 'gently' (as compared to what could be called the 'ham fisted' conventional approach of today's other xPAPs) manipulate the airflow to sustain a pattern with a 90% minimum target. It seems that the machine's algorithms are very well thought out & these algorithms have the technology in the low mass high-inertia dual impeller blower, to provide highly accurate therapy. Better hardware technology was needed to match the algorithms. The issue then being keeping the cost down so that the resulting advances can be translated into a conventional AUTO at a reasonable cost.

This type of machine should benefit just about everyone. It should at last provide us with an AUTO that is truly capable of stopping even the quickest Apnea event from occurring & preventing subsequent ones. Many of the debates & some heated arguments that have taken place here in the recent past relate to just how effective current AUTOs really are at what is implied in what they can do vs what they are technically capable of allowing for their current technology..

If Resmed could put the CS2 type technology into a moderately priced AUTO they could reshape the whole xPAP market & set a new level for effectiveness & compliance.

Again I wonder if their efforts at killing the eBay market for used xPAPs is a pre-emptive strike in advance of introducing new CS2 based models of their machines.

The thought is also in my mind that if they did hit the market with such a machine, the only selling effort would be the mask fit as the machine should do the rest ? who needs a sleep study to tell you to go buy a self adjusting all seeing all adapting supapap

Hmmmmm

DSM

Yes I like that - The new competition killing ' SupaPap'

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rested gal
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Post by rested gal » Tue Jul 25, 2006 6:48 am

dsm wrote:This type of machine should benefit just about everyone.
That's what I thought, too, dsm, when I first started reading about the CS 2 in HH's posts on the TAS board in 2004.

It's easy to get enthusiastic about such breakthrough technology in the AutoSet CS 2.

For now it sounds like the algorithms and technology in the CS 2 are aimed very specifically at correcting CSR (Cheyne Stokes Respiration) as well as dealing with obstructive apneas in one class of patients - those with Congestive Heart Failure. That's not to say there might be not be other people who could benefit from that particular machine.

As one of the doctors who was interviewed in the ResMedica newsletter put it, a varying level of pressure support can be "annoying". Not to mention the very important issue of using a leakproof FF mask and/or absolutely controlling mouth air leaks if not using a FF mask, with a machine where sensing the air flow accurately is absolutely critical to the performance.

http://resmed.com.au/Newsletters/Static ... 0911r1.pdf

Adaptive servo-ventilation in patients
with periodic breathing during sleep

Dr.Winfried Randerath

excerpt from page 7:

Although the results were favourable, a number of
problems were observed in the introductory phase
of the treatment, and with long-term use. For
example, it was found that some patients repeatedly
interrupted treatment during the night. Particularly
those who have dyspnea or frequent nocturia,
tended to have some problems using the AutoSet
CS. The software for the device requires therapy
phases lasting 3 minutes in order to acquire sufficient
data for optimal pressure adjustment between one
breath and the next. So frequent removal of the mask
during the night impairs effectiveness of adaptive
servo-ventilation. As a result, this form of therapy
requires the patient to have a better understanding of
the treatment than is the case with CPAP therapy, for
example. Another disadvantage with protracted use
is that the complex algorithm used for the device is
intolerant of large leaks and so most patients are
ideally treated with Mirage Full Face masks.These are
only available in three sizes, and in some some
instances, we were unable to find appropriate tightfitting
masks. In such cases, the only options are either
to tolerate a significant leak or to refrain from using
this form of therapy.
The introductory phase required considerable time
input from the staff providing medical care. In addition
to the important factor of mask optimization, patients
needed to be trained in the operating principle of
adaptive servo-ventilation, so that they would not find
the varying level of pressure support annoying.


I recall a post by someone (I'll try to find it sometime) who did get the CS 2 about a year ago and found it unusable due to the pressure changes. I don't know whether he bought it on his own, or if he had the kind of "patient training" and "better understanding of the treatment than is the case with CPAP therapy" mentioned by Dr. Randerath. Don't know whether the man was even a CHF patient who would need that particular machine.

It sounds like the CS 2's technology is much more intolerant of leaks than are current APAPs. Given the many ways leaks can occur with mouth or mask, I can envision a much more 'ham fisted' feeling of treatment delivery from a CS 2 than from conventional autopaps. Perhaps that was what was happening to the man who wrote of not getting along at all with a CS 2.

Of course, if a person has Cheyne Stokes Respiration and is suffering from Congestive Heart Failure, they would/should do whatever it takes to use the CS 2 machine. It's a true breakthrough machine for them -- extending life and improving quality of life in a noticeable enough way to keep them sticking with it. Hopefully the person setting them up would be extremely well trained at getting it right and dealing with mask issues.

I realize you're not saying the CS 2 is the all-things-to-all-people xpap machine right now, dsm. I agree that the technology is quite unique...a real breakthrough for the very specific group of Congestive Heart Failure and Cheyne Stokes Respiration patients it's designed to treat.

It's interesting to speculate on what might be developed from the CS 2 technology that could benefit more and more patients in general. I just wanted to mention a few things in case a "regular OSA sufferer" out there who has the means to buy whatever machine he wants, but who doesn't fall into the CHF/CSR group gets the impression that the super machine is already here.

It's certainly a lifesaver for a select population who absolutely need it. It would probably be very annoying treatment delivery for those who don't need such a machine.

-SWS
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Post by -SWS » Tue Jul 25, 2006 8:35 am

Rested Gal, thanks so much for straightening out the easily recognizable "waxing and waning" patterns of Cheyne Stokes respiration. I recall having read many times over the years what an easily recognizable pattern CSR is to observe. Snoredog, CSR and its own unique algorithmic recognition criteria is easy to confuse with recent discussions we've had about CSDB and it's own unique research-oriented recognition challenges (discussed in the Apnea -v- Hypopnea thread). And, of course, CSR and CSDB are two very different hypocapnic SDB conditions. Periodic breathing in non-CSR patients would be yet another pattern rich waveform for algorithmic recognition, which AutoSet CS2 undoubtedly works with as well.

Cheyne Stokes Respiration was undoubtedly an excellent "first choice" pattern for the original AutoSet CS algorithm to work with. As such, the AutoSet CS originally targeted only Cheyne Stokes Respiration.

By contrast the sequel machine, the AutoSet CS2, is now marketed to treat central apneas in all its forms, and I can't tell you how surprised I was to read that just a couple days ago. As Rested Gal well points out, the AutoSet CS2 is not currently marketed to treat all sleep disordered breathing (SDB) conditions----only "central apnea in all its forms". And I should also point out that the jury is still out, so to speak, regarding the efficacy the AutoSet CS2 algorithm presently manages to achieve with respect to non-CSR central apnea disorders. In general, ASV or "adaptive-servo ventilation" has great SDB therapeutic potential in my honest opinion. DSM seems to echo that optimism as well. However, the AutoSet CS2 is just not currently equipped (within the design constraints of the algorithm) to treat non-central-apnea SDB. And in the vast majority of SDB cases, subtle xPAP ventilatory "overshoot" is a non-issue. In other words, subtle xPAP ventilatory "overshoot", which adaptive-servo ventilation very nicely addresses, is entirely irrelevant to most of us.

I think there is admittedly a general human-nature trend to over-generalize the concepts and discussions regarding comparatively rare CSR and CSDB sleep disorders---very likely in part because those discussions are so extraordinarily fascinating. We must avoid the temptation to over apply any rare SDB cases when drawing conclusions about our much more etiologically "common" SDB conditions. Similarly, we must also avoid over-generalizing the principles of any one rare hypocapnic etiology (CSR) with yet another rare hypocapnic etiology (CSDB). Yet drawing correct similarities and key associations can be very helpful in general. These are all very complex topics, indeed.

This really has been a fascinating thread and I have been learning much along the way, thanks in a very large part to the contributors in this thread. Thanks to a wonderful round-table discussion, I think we're really starting to get an idea of what the AutoSet CS2 is all about, and how it rather uniquely accomplishes its ventilatory-related technical objectives.


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Post by dsm » Tue Jul 25, 2006 2:58 pm

RG SWS,

I am playing with VPAP IIIs at the mot - I have a VPAP III & will soon have a VPAP III S/T.

I am comparing it on night by night trials with a new Bipap S/T (gray model).

The 1st thing I notice with the VPAP III is that it seems to do adjustments to breathing patterns that in some way mimic some of what id described in the CS 2 documentation.

The blower was noisy last night (funnily it didn't seem to be on earlier nights ?)
When I 1st go to bed, the machine seems to flip from IPAP 2 EPAP 2 early (I am on 15/8 & f/f mask) this was a complaint I had with the Bipap S/T. BUT, unlike the Bipap S/T which seems to do the early flipping all night, the VPAP III, withing about 5 mins, seems to extend out to match my preferred breathing. Eventually it seems to be in synch (in fact they write about their inSynch feature & for me it really does work.

The Bipap S/T is supposed to do this synching but it doesn't seem anywhere near as effective as the VPAP III. The Bipap S/T blower is noisier but because these Bipaps use an air valve to change air pressure, the constant speed of the blower seems easy to adjust to vs the up & down 'whine' or 'hum' of the VPAP III.


It will be interesting to ompare the VPAP III S/T to the Bipap S/T (perhaps a fairer comparison).


I also had this Whine hum issue with an S7 Spirit AUTO but no problem with the fixed pressure mode of the otherwise identical S7 Elite.

Re the CS2. I believe the last problem to be solved in current AUTO designs is the speed with which they will be able to preempt SDB of any sort.

The CS 2 can deal with Centrals, this was one important bit missing from current AUTOs, also the new high-performance blower may be what can make a difference in preempting all Apneas. Ir reality it is too late to try & clear a serious Apnea once the lungs pull the throat shut. The best most AUTOs will achieve is to be ready with higher CMS for the next one. Perhaps a CS2 type blower & enhanced AUTO algorithm will do the trick & get there before the throat closes ?.

Interesting stuff & thanks RG for the other perspective. Helps dampen the potential for 'over enthusiasm' we sometimes exhibit when new technology appears

DSM

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Post by dsm » Tue Jul 25, 2006 3:16 pm

An interesting development for me.

When I began using the VPAP III some nights ago I had negotiated with my wife to use the spare bedroom until I got used to this machine.

I was also quietly wondering what comments she might eventually make allowing that this is a straight Bilevel vs the S/T model (still on its way).

Last night my wife resumed sleeping in the main bedroom with me & I believed I had a very good night with the VPAP III.

This morning at breakfast & without any prompting she asked me if this machine had breathing control, I asked why she asked, she said just tell me if it does or doesn't, I then informed her it doesn't. She then said well you kept me awake much of the night when you would just stop breathing & the machine would whine. She asked me to revert back to the previous machine (PB330 with A/C).

For myself, I don't feel any different (as far as I can tell) from sleeping with the PB330 with A/C. So I am a bit puzzled by this. I was wondering if this would be an issue, well it showed up straight away. I don't quite know what the situation is, it sounds somewhat like Centrals of some sort (my heart is in great shape - did a full stress ECG l18 months back & I don't have high blood pressure).

I am now looking forward to getting the VPAP III S/T to try.

DSM
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Post by christinequilts » Tue Jul 25, 2006 4:16 pm

Well, as RG & SWS probably already guessed, I am very anxious to get my hands on the new ResMed machine. My only concern is my bad history with ResMed VPAP ST (both II & III's)- they have never figured out why I don't do as well with them as I do with Respironics Synchrony or its older relative, BiPAP STD...or even the Quantum PSV I used for my first months trial (Note to dsm- you would have fun playing with all the function on that machine:wink:). I still think my problem with VPAPs had to do with my centrals not responding all that well to start with, with only going from 65 centrals per hour to 30+ on my first titration, and maybe VPAPs even do that. Thankfully my numbers have improved over time, as my body adjusted to BiPAP ST, but it would be interesting to see if the new machine does any better & if by some chance, correcting more of the centrals might help with the severe Alpha Wave Intrusion.


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Post by rested gal » Tue Jul 25, 2006 4:35 pm

christine, I thought of you immediately when I read the marketing statement about the AdaptServo:

"adaptive-servo ventilation:

*
treats complex sleep apnea syndrome and central sleep apnea
*
normalizes breathing, completely suppressing CSA
"

Hope you get to try one!

Guest

Post by Guest » Tue Jul 25, 2006 5:18 pm

[quote="christinequilts"]Well, as RG & SWS probably already guessed, I am very anxious to get my hands on the new ResMed machine. My only concern is my bad history with ResMed VPAP ST (both II & III's)- they have never figured out why I don't do as well with them as I do with Respironics Synchrony or its older relative, BiPAP STD...or even the Quantum PSV I used for my first months trial (Note to dsm- you would have fun playing with all the function on that machine:wink:). I still think my problem with VPAPs had to do with my centrals not responding all that well to start with, with only going from 65 centrals per hour to 30+ on my first titration, and maybe VPAPs even do that. Thankfully my numbers have improved over time, as my body adjusted to BiPAP ST, but it would be interesting to see if the new machine does any better & if by some chance, correcting more of the centrals might help with the severe Alpha Wave Intrusion.


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dsm
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Post by dsm » Tue Jul 25, 2006 5:19 pm

Above *is* me guested

DSM
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Beatrice

Post by Beatrice » Tue Jul 25, 2006 8:38 pm

dsm wrote:This morning at breakfast & without any prompting she asked me if this machine had breathing control, I asked why she asked, she said just tell me if it does or doesn't, I then informed her it doesn't. She then said well you kept me awake much of the night when you would just stop breathing & the machine would whine. She asked me to revert back to the previous machine (PB330 with A/C).
I wonder if this could be happening to me too but I live alone and don't have anyone to tell me. How can I find out if I am stopping breathing at night and the machine is just whining and not doing me any good? Does that mean you have central sleep apnoea? Is there any other way to find out for certain besides having someone watch me breathing whilst I am asleep?

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dsm
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Post by dsm » Tue Jul 25, 2006 9:45 pm

Beatrice,

I am going back to talk to my breathing disorders specialist. I think I have enough input to discuss with him what I should do to get to the bottom of this.

I am not coming to any firm conclusions yet as to be honest, whilst it looks like centrals may be involved in my case, I don't have enough supporting data to state it as a fact. As astute as I believe my wife's observations are I would not bet my life on them but in the absense of other input she is the best I have

The typical Cheyne Stokes pattern doesn't seem to fit with me being basically healthy - no known heart problems & none in family. Never had any respiratory / lung problems other than the current GERD/Apnea related & classic symptoms.

My symptoms do seem to be mostly at start of nights sleep and prior to waking. This has been discussed here before. Some think these symptoms are not any real issue. I tend to agree if oxygen desats aren't also occuring.

DSM

#2 PS - part of what is frustrating with many Bilevel S/T machines is that most current models don't have detailed nightly data recording, whereas many straight Bilevels (No S/T) do

D
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Beatrice

Post by Beatrice » Tue Jul 25, 2006 11:26 pm

Is the only way to know if I am having the central apnoeas going to require revisiting the hospital and wiring up overnight?

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Post by dsm » Wed Jul 26, 2006 12:37 am

As a postscript to today (after what happened at breakfast as posted above) I can say I have had a good day, no sleepiness & have maintained a general feeling of alertness. A 'good' day.

But I have booked to see my original respiratory specialist (just need to also obtain a 'referral' from my GP).

I like the VPAP III so will be disappointed to be switching back to the PB330. I might do some further nights with the Bipap S/T (gray model) even though I tried it for 3 nights (2 with full face mask) & gave up.

Having used the VPAP III though, I will do some readjusting of the PB330. The VPAP III is so easy to set up compared to the PB330 which has adjustments for so many different functions (Rise Time, Ipap sensitivity, Epap sensitivity, predicted mask leak rate, IPAP cms, EPAP cms, Ratio of IPAP to EPAP, Fallback BPM - then it has a wide range of pressure & flow alarms & levels (but I turn them all off)). A bit like trying to prepare to fly a jet aircraft.

Cheers

DSM

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StillAnotherGuest

ASV by CS-2

Post by StillAnotherGuest » Wed Jul 26, 2006 5:25 am

Hmmm, seems interesting, but I'm really wondering how popular it's going to get.

Right, the CS-2 originally had a target group that was comprised of CSR secondary to CHF. However, with improved treatment of congestive heart failure (CHF), particularly the widespread use of ACE Inhibitors, the incidence of CSR is now greatly reduced. Or, put differently, patients with CSR are more likely suffering from uncontrolled CHF. Like what would happen with inadequate care. Or if they're non-compliant with medications. And if somebody's non-compliant with medications, what chance is there of having them use a CPAP mask?

And trust me, when many members of the medical community hear CSR, they think uncontrolled CHF.

So now comes the shift in attention to idiopathic CSR. One wonders if it's because of changing market projections, but it would seem as though ASV would work in theory if the mechanism is the same (and that mechanism must almost certainly have to be circulatory delay. If it's controller gain, then no matter what BiLevel you use, you will only make the problem exponentially worse). If it is an issue with circulatory time, then (and quite counterintuitively), using 2 different pressure algorithms with CS-2, you can (probably) avoid the feedback gain that perpetuates periodic breathing when using traditional BiLevel S/T intervention by attenuating the effect of hypercapnia (yeah, I know, hypocapnia is the trigger, but it's the hypercapnia that perpetuates the havoc, cause eventually you have to breath again). If phase lag = 180 degrees, the response to hypercapnia increases feedback (and ultimately, controller) gain, creating LG ~1. Thus, effective ventilation through apneic periods may correct that other inadequacy of BiLevel S/T ventilation, namely, insufficient ventilation during periods of central apnea.

What will be interesting to follow will be if ASV will become front-line treatment for CSBD before enhanced CO2 systems. That's going to be a steep learning curve, because if the central component of CSBD is largely iatrogenic (and if it's discovered during aggressive pressure titrations, then it is), getting people to recognize when effective management of obstruction has occurred is going to be tough.

And you're also going to have to make sure all the obstructive apneas are taken care of by 10 cmH2O if you're going to use a CS-2. Although that should happen in most cases.

While the concept of CSBD is fun, it is clear to me that CSBD is not a "new" phenotype at all (the role of hypocapnia and use of enhanced CO2 to treat it has been around for like 20 years), just the coincidental occurence of (1) a tendency toward periodic breathing; (2) some degree of obstructive SDB; and (3) inappropriate use of pressure therapy.

To reiterate, keep in mind that these pressure therapies are only treating the problem symptomatically. If the underlying central component is due to untreated or uncontrolled CHF, and you have an EF <40%, then this whole approach is not the best way to go about doing things. While controlling the apneas and desaturations associated with CSR will offer some benefit, and maybe a lot, you have to optimize the other facets of CHF treatment first.

I would also take exception to the line about "to treat CSA in all its forms." For anyone whose CA is post-arousal in nature (which so far is everybody in this thread except christinequilts) this technology would be at the least a monumental waste of money. And at at the most...hmmm, I'm not sure what "at the most" would be. If the CA was purely as a result of controller gain (overly aggressive pressure titration)(and you can do that in normals)(and by normal that means phase lag=0) then even this machine would begin to generate periodic breathing.

However, if you're referring to the recent article in one of the sleep journals about the use of ASV in idiopathic CSR, let me point out that (1) it's still CSR, and (2) that small group all had significant baseline bradycardia.

See? It's always circulatory delay!
SAG

PS to Beatrice - Absolutely you need PSG to diagnose and treat these issues.