Resmed VPAP Adapt SV - for Central Sleep Apnea

[dsm]

YAG,

A question,

"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. "

Why would the OSA events need to be taken care of by 10 cms ? - (why 10 in particular ?)

Is that related to existing technologies ability to 'manage' OSAs ?

Tks

DSM

[Chriton]

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.

I gather if one is experiencing typical post-arousal CA, which are viewed as normal hysiologic events, the use of a machine capable of generating periodic breathing is unnecessary. Is it fair to say, while unnecessary, it's use would provide the ultimate treatment wherein even common post-arousal CA would be addressed?

[rested gal]

YAG,

A question,

"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. "

Why would the OSA events need to be taken care of by 10 cms ? - (why 10 in particular ?)

Is that related to existing technologies ability to 'manage' OSAs ?

Tks

DSM

Not to jump in when the question is directed to YAG...but this might explain it little.

It's my understanding (limited at best!) that it is related to a design choice by ResMed which they call the "A10 algorithm". "10" as the maximum pressure for their auto-titrating machines to use when sensing an apnea. That cap of 10 is based on two premises by ResMed:

A: the majority of patients' obstructive apneas can be corrected with 10 cm H20 or less pressure.

and...

B: that 10 cm H20 usually will not cause pressure induced centrals.

So.... 10 cm H20 is the built-in safety cap ResMed chooses to put on the maximum amount of pressure their autopaps can use against what they sense as an apnea. 10 cm and no more.

Why no more? Because the cessation (or near cessation) of air flow from the person might be due to a central apnea instead of an obstructive apnea. If it's a central apnea (throat already open, brain not sending signal to "breathe") then using more, and more, and more pressure to try to open an already open throat would be useless.

For the same statistical reasons, Puritan Bennett autopaps also have "10" cm built in as the most amount of pressure their autopaps will use against an apnea. However PB autopaps have an "Advanced Settings" menu where the "Maximum Pressure for Command on Apnea" can be changed to higher or lower than the factory default of 10.

I don't know if the AdaptServo has a similar "advanced" setting that provides a way to change ResMed's A10 algorithm's built-in maximum of pressure (10 cm H20) to be used against obstructive apneas.

Look for -SWS's posts in past topics. A few examples:

viewtopic.php?t=2422
Page 3

Guest, Resmed has published the A10 algorithm as specifically holding a pressure response "command on apnea" at 10 cm or less to avoid what they term "runaway central apneas" (which specifically refer to pressure-induced occurences). The other AutoPAP manufacturer's also take great care (expressed in great detail in their patent descriptions) to avoid the pressure-induction of cental apneas as well. However, none of these manufacturers give us patient-based probabilities or statistics relative to the pressure induction of central apneas. Yet, if the rate was not significant across the SDB patient population, why would all of the manufacturers devote so much development cost and effort toward avoidance of pressure-induced central apneas?



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About the "Max pressure command on apnea" advanced setting in PB 420E autopaps:
viewtopic.php?t=817
Page 2

That third adjustable parameter is really best thought of as an AutoPAP pressure-response "safety limit" or "safety cap" to help in the avoidance of pressure induced central apneas (which can easily escalate in some patients, manifesting in a condition referred to as "runaway" central apneas). This "command on apnea" setting is defaulted at 10 cm on the 420e. That 10 cm default limt has very sound statistical basis across the apneic patient population with respect to air pressures at which central apneas are known to manifest in significant numbers.



_________________________

viewtopic.php?t=1483
bottom of Page 2

The RemStar/Encore NR apnea category will log primarily central apneas, but any apnea that did not respond to those three pressure increments will be logged as NR---exactly as you described.

The 420e strives to avoid pressure-inducing central apneas with these two techniques: 1) cardiac-oscillation detection algorithmically equates to either maintaining pressure or backing down, and 2) the adjustable "command on apnea" setting imposes an upper pressure limit with which any apnea may be treated.

[dsm]

RG,

Thanks for stepping in, that was info I had not read before (I had been through some patent applications discussion how Respironics responded to detected Apnea vs Central). I interpreted their agorithm as being capable of free-ranging to 8 cms then limiting further rises to max 3 cms thus a total of 11 cms before they would revers the increases.

I also had save quotes from Resmed representative about how their machine (of the day) would stop increasing pressure if an Apnea with a full flow-limitation had been detected. This approach stated that they regarded it as too late to adress the Apnea with increased pressure but would wait for this one to clear then up pressure in anticipation of a next one.

Thanks

DSM

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CPAPopedia Keywords Contained In This Post (Click For Definition): respironics, resmed

[-SWS]

DSM, Respironics will free-range up to 8 cm, then limit direct apnea pressure responses to exactly three pressure increments thereafter. Thus if an apnea occurs at say 14 cm, a three-increment limit translates to as much pressure as 17 cm (less may be required). Resmed will directly respond to an apnea, but will limit that response to 10 cm. It will leverage apnea treatment as much as possible by preemptively responding to snore and flow limitations as if they were indicative precursors to likely apneas. Resmed poses no pressure limit in direct response to snores or flow limitations, however. Here are some nifty quotes from Respironics and Resmed, respectively:

"The REMstar Auto algorithm looks for apnea’s that are non-responsive to treatment which could indicate that these are central events. At any pressure 8 cm H2O or higher we will make three pressure increases in response to a sustained string of events. If there is no improvement after the third increase, indicated by the persistence of events, the pressure is dropped 2 cm and a constant pressure is held for several minutes. If there is snoring noted during this period of constant pressure, which would indicate obstruction, we will increase pressure and reset the non-responsive treatment, thus allowing for three more pressure increases. Apneas can potentially be treated up to the device's maximum pressure setting (20 cm H2O)."

The above text is taken from the following cpaptalk.com interview:
viewArticle/Respironics-Remstar-Auto-Pr ... rview.html

"The A10 algorithm increases pressure in response to Flow Limitation, Snore, and Apnea up to 10cm H2O. Above 10cm H2O, pressure response to Flow Limitation and Snore continues, but there is no response to Apnea. AutoSet Spirit and AutoSet T do not differentiate between obstructive and central apneas. Increasing pressures above 10cm H2O in response to apnea can lead to "runaway" central apneas."

The above text is taken from the following talkaboutsleep.com interview:
http://www.talkaboutsleep.com/sleep-dis ... itchat.htm

Hope this helps!

[-SWS]

SAG, interesting comments. After I finish with a batch of client-based work over the next several days I'd like to go through some of your comments in detail. However, the one comment that I'd like to bring out is the comment about AutoSet CS2 not being able to treat all forms of central apneas. There may be some truth to that. Then again...

One of two very profound outcomes are inevitable regarding those sweeping Resmed central apnea claims: 1) they will prove to be unfounded, in which case Resmed will receive incalculable medical and corporate credibility damage, or 2) adaptive-servo will prove to correct those central apneas after all, in which case old-model respiratory and neurological analyses of central apnea will have to be seriously augmented regarding the very "front-end" of central apnea's physiologic model of dysregulation.

I personally suspect the latter of those two possibilities is the case. Resmed knows perfectly well how central apnea patients do or do not respond to adaptive servo when it is coupled with the correct mathematical modeling. I can't picture Resmed observing that adaptive servo fails all but CSR, then making corporate self-destructive claims to the contrary (even if Resmed's corporate practices show a clear pattern of methodically trying to kill off Internet-based vendor sales).

The ensuing data will tell if Resmed must suffer incalculable credibility damage or if the medical world will have to revisit when, how, and why dysregulative central apneas occur. The medical world freely admits they don't understand the intricate relationships key chemoreceptors play in dysregulated central or autonomic breathing. I'm throwing my cards in with autonomic breathing's adaptive neural plasticity as actually being rudimentary and maladaptive under certain physiologic instances. And that is not an issue of respiratory controller gain as much as it may very well be an issue of autonomic breathing's adaptive neural plasticity assigning a rather "maladaptive" priority gain to various chemoreceptor signals such as stretch receptors in the case of CSDB. I'll eventually expand that theory in the Apnea -v- Hypopnea thread.

[-SWS]

Christine, I've only thought about you a dozen times since this thread started. Lo and behold you show up. It is so good to hear from you! I too hope you get to try an AutoSet CS2! .

[StillAnotherGuest]

Not to jump in when the question is directed to YAG...but this might explain it little.

It's my understanding (limited at best!) that it is related to a design choice by ResMed which they call the "A10 algorithm". "10" as the maximum pressure for their auto-titrating machines to use when sensing an apnea. That cap of 10 is based on two premises by ResMed:

A: the majority of patients' obstructive apneas can be corrected with 10 cm H20 or less pressure.

and...

B: that 10 cm H20 usually will not cause pressure induced centrals.

So.... 10 cm H20 is the built-in safety cap ResMed chooses to put on the maximum amount of pressure their autopaps can use against what they sense as an apnea. 10 cm and no more.

Why no more? Because the cessation (or near cessation) of air flow from the person might be due to a central apnea instead of an obstructive apnea. If it's a central apnea (throat already open, brain not sending signal to "breathe") then using more, and more, and more pressure to try to open an already open throat would be useless.

For the same statistical reasons, Puritan Bennett autopaps also have "10" cm built in as the most amount of pressure their autopaps will use against an apnea. However PB autopaps have an "Advanced Settings" menu where the "Maximum Pressure for Command on Apnea" can be changed to higher or lower than the factory default of 10.

I don't know if the AdaptServo has a similar "advanced" setting that provides a way to change ResMed's A10 algorithm's built-in maximum of pressure (10 cm H20) to be used against obstructive apneas.

Look for -SWS's posts in past topics. A few examples:

viewtopic.php?t=2422
Page 3

Guest, Resmed has published the A10 algorithm as specifically holding a pressure response "command on apnea" at 10 cm or less to avoid what they term "runaway central apneas" (which specifically refer to pressure-induced occurences). The other AutoPAP manufacturer's also take great care (expressed in great detail in their patent descriptions) to avoid the pressure-induction of cental apneas as well. However, none of these manufacturers give us patient-based probabilities or statistics relative to the pressure induction of central apneas. Yet, if the rate was not significant across the SDB patient population, why would all of the manufacturers devote so much development cost and effort toward avoidance of pressure-induced central apneas?



___________________________

About the "Max pressure command on apnea" advanced setting in PB 420E autopaps:
viewtopic.php?t=817
Page 2

That third adjustable parameter is really best thought of as an AutoPAP pressure-response "safety limit" or "safety cap" to help in the avoidance of pressure induced central apneas (which can easily escalate in some patients, manifesting in a condition referred to as "runaway" central apneas). This "command on apnea" setting is defaulted at 10 cm on the 420e. That 10 cm default limt has very sound statistical basis across the apneic patient population with respect to air pressures at which central apneas are known to manifest in significant numbers.



_________________________

viewtopic.php?t=1483
bottom of Page 2

The RemStar/Encore NR apnea category will log primarily central apneas, but any apnea that did not respond to those three pressure increments will be logged as NR---exactly as you described.

The 420e strives to avoid pressure-inducing central apneas with these two techniques: 1) cardiac-oscillation detection algorithmically equates to either maintaining pressure or backing down, and 2) the adjustable "command on apnea" setting imposes an upper pressure limit with which any apnea may be treated.

Hmmm, that's a much better answer than mine.

All I got is, "Cause that's as high as it goes."

The End Expiratory Pressure (EEP)(why they don't standardize everything and just call it EPAP is beyond me) in the CS-2 ASV Mode has a range of 4 to 10 cmC2O, but then that becomes fixed. Obstructive events are addressed by adjusting baseline EEP. It then addresses central events by rapidly increasing PSmin up to PSmax (if necessary) until volume targets are met. Situations where more baseline pressure is needed to address obstructive events may therefore be a problem. But as noted, not a lot of CHF or CSBD patients need more than 10 cnH2O CPAP/EPAP/EEP to control obstructive events. If they're only hypopneas, maybe they'll be taken care of by the BiLevel nature of the machine (but that's ordering off the menu).

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.

I gather if one is experiencing typical post-arousal CA, which are viewed as normal hysiologic events, the use of a machine capable of generating periodic breathing is unnecessary. Is it fair to say, while unnecessary, it's use would provide the ultimate treatment wherein even common post-arousal CA would be addressed?

I going with absolutely not. Post-arousal CA is the body's response to achieve homeostasis following a event (usually brief hyperventilation). Trying to ventilate through that period prevents that from occurring.

Besides, post-arousal CAs are benign. The problem was the event that precipitated it. The patient is usually back to sleep by CA termination, and often in the middle of it. Unless something else disturbs that transition.
SAG

[SM-Guest]

SWS,

Many thanks - each time you restate something I understand it a little bit more

This is an interesting thread.

Cheers

DSM

PS - I sat down with wife last night to go over why she thought I had been stopping breathing in the previous night while on the VPAP III. As I had said, I felt great all day & felt I had had a good night's sleep.

Remembering that it was this condition prior to me taking up Apnea, that alarmed her most & prompted me to go to a respiratory specialist & then do a sleep study etc:

6 or so months into therapy I began to feel a reversion of good results & felt I was sliding back to pre therapy tiredness. I had been on straight cpap for the 1st month, then a mix of autos & straight cpap for 5 or so months.

1st 3 months were a 'high'. Then a slow decline set in.

Getting back to wifes observations. At the time I felt I was really going backward (about 5 months in) Wife began telling me I was reverting to stopping breathing & that the she could hear the machine straining & air leaking & me just there not breathing. I was aware of this slowing breathing and stopping. I didn't know if it was a problem or not. So got a PO & also was given the chance to obtain a PB330 Bilevel with Assist/Control (Timed).

Once I started using the PB330 - back came the wakefulness & good feelings.

So on tuesday night the 1st night wife was present when I was using the VPAP III (which has no timed control) and wife had said next morning you weren't breathing & the machine was whining, I was puzzled because I felt the sleep & day went very well.

Last night I explained to her that unlike the PB330 which has no distinct engine noise, the VPAP III does have a noticable hum/whine that goes up & down. When it is up (to her the machine straining) I am breathing in (IPAP) when it goes down I am breathing out (EPAP). Because this machine is new to her & its sounds so different, I am satisfied she was mis-interpreting my breathing on this occasion (she was right pre cpap therapy & she was right while I was on straight cpap, but this time I think she was wrong). She did agree that when she heard the high hum, she thought I was not breathing & this disturbed her sleep. I am satisfied I had a normal nights sleep & that the VPAP III was only guilty of making strange (to her) noises that she subsequently misinterpreted. The proof to me on this is that if I slow & stop breathing with the VPAP III, it stays in EPAP mode & thus when she was hearing a high hum, it was in IPAP mode & it would only be in that mode because I was breathing in ok.

But to avoid her getting disrupted sleep (week nights) I will stick to the PB330 that she is comfortable with (& does fine for me anyway) but come the week-end back out comes the VPAP III.

Also I spent last evening trying to work with the Bipap S/T Gray model & one Bipap Pro 2 to see if I can come up with better adjustments to eliminate the early flipping. After 3 hours of trying every combination of rise-time, Ipap duration setting, etc:, I gave up in frustration. Even the old 'boxy' Bipap S/T works better than these 2 'new' models. I tried different masks even a nasal pillows mask but the frustrating early flipping just kept happening.

I would love to have a respironics rep explain the AUTO-TRAK feature in detail, I might be able to help then re-work the algorithm.

DSM

[dsm]

One comment I meant to include in the above post (but being guested I was unable to add), is that with the Bipap S/T (gray) & the Bipap Pro 2s (2 of them), they all work ok when I have my f/f mask on but breath thru my mouth !. I am sure there is something in this, my belief is the AUTO-TRAK regards me nose breathing as inadequate airflow or a leak.

The moment I start breathing thru my nose the early flipping starts. Sometimes it can be as quickly as 1/2 way thru a breath.

I do have a bit of difficulty breathing thru my nose but don't believe it is that big an issue that it would affect how one brand of Bilevel works.

To add perspective, I have tried all these Bilevels & it is only the 3 new Respironics Bipaps that are affected

1 ) PB330 A/C works great - any type of mask - lets me breath thru nose easliy
2 ) Healthdyne BiLevel (as for 1 - a delightful Bilevel - very fine sensitivity)
3 ) PB 320 (old clunker predates PB330) as for 1, works ok, noisy as a 727
4 ) Respironics Bipap S/T 1st model - works fine - noisy as a 707 (very)
5 ) VPAP III - works fine like 1 - I like it - wife disturbed by its bi-level hum
6 ) Bipap Pro 2 (1 hour on the clock) flips early always has - 2 nights use (& gave up)
7 ) Bipap Pro 2 (1600 hours on the clock) flips early always has - 1 night use
8 ) Bipap S/T (newest Gray model) flips early always has - 3 nights use

The only commonality is the AUTO-TRAK on 6, 7 & 8.

DSM

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CPAPopedia Keywords Contained In This Post (Click For Definition): respironics, bipap, auto

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CPAPopedia Keywords Contained In This Post (Click For Definition): respironics, bipap, auto

[Guest]

See? It's always circulatory delay!

Always?

[Guest]

I would love to have a respironics rep explain the AUTO-TRAK feature in detail, I might be able to help then re-work the algorithm.
DSM

It is probably not worth your time and effort unless they agree with your belief the algorithm needs to be re-worked. Have you tried contacting them? Nothing ventured nothing gained.

[Guest]

I would love to have a respironics rep explain the AUTO-TRAK feature in detail, I might be able to help then re-work the algorithm.
DSM

It is probably not worth your time and effort unless they agree with your belief the algorithm needs to be re-worked. Have you tried contacting them? Nothing ventured nothing gained.

[DSM-Guest]

dang, can't correct typo in prior post. Was supposed to say I sure *won't* be buying yet another one of those model Bipaps just to prove yet again what is clearly a problem. I know exactly how another one will behave.

I doo however believe the Bipap AUTO uses different algorithms. I do plan to get one of them at some point & evaluate it.

DSM

[Chriton]

I ran across this in another thread and it seems apropos here as well. It is part of this post viewtopic.php?p=97023#97023

you cannot take any one person's response to an APAP algorithm and conclusively generalize that single person's response across an entire apneic patient population. The laws of probability across an extremely physiologically diverse human population simply don't work that way. That statement is true of BiLevel algorithms as well, IMO.

What one person describes as "clearly a problem" with a particular machine or algorithm is their opinion based upon their experience and cannot be assumed to be a problem for everyone else.