S9 Reviews

General Discussion on any topic relating to CPAP and/or Sleep Apnea.
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ozij
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Re: S9 Reviews

Post by ozij » Mon Mar 08, 2010 7:13 am

jnk wrote:I would like to know what definition this machine uses for scoring a hypopnea.
So would I.

I assume that now that they are identifing central apneas, they changed their approach to hypopneas -- both in recording and in responding.

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jnk
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Re: S9 Reviews

Post by jnk » Mon Mar 08, 2010 7:42 am

ozij wrote:
jnk wrote:I would like to know what definition this machine uses for scoring a hypopnea.
So would I.

I assume that now that they are identifing central apneas, they changed their approach to hypopneas -- both in recording and in responding.
This is all I have been able to find. But without a clear definition of how they now establish baseline, it doesn't say much.
"Hypopnea -- A hypopnea is an episode of shallow breathing during sleep. A hypopnea is scored when there is a reduction in breathing by 50% of baseline breathing with partial upper airway obstruction for 10 seconds or more. The event is scored after 10 seconds of the hypopnea."-- http://www.resmed.com.sg/us/assets/docu ... er_eng.pdf
I always liked the high estimated HI in ResMeds. It gave more information for trending and tweaking. 0.0 estimated events is useless for, uh, "zeroing" in on the most effective pressure(s), in my opinion.

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ozij
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Re: S9 Reviews

Post by ozij » Mon Mar 08, 2010 8:24 am

To the best of my understanding, the A10 algorithm (which is used up to and including the s8 II series) did not use obstruction indicators in hypopneas, this is the Autoset's definition (my emphasis):
Autoset clinician's manual wrote:A hypopnea is defined as a 50 to 75% drop in ventilation. A hypopnea is scored
if the 8-second moving average ventilation drops below 50%, but not below
25%, of the recent average for 10 consecutive seconds. In order to avoid falsely
responding to central hypopneas, the AutoSet algorithm does not respond to
hypopneas but rather to the associated snore or flow limitation
The S9 definition you found, jeff, hints (in my mind) that this time around Resmed's enhanced algorithm can distinguish the presence of a partial obstruction during the hypopnea. The A10 seems to have been incapable of that. If indeed the new algorithm has an improved ability to detect obstructions, the could explain the smaller number of hypopneas reported.

I felt I could never know if ResMed hypopneas were of central origin or obstructive -- and consequently, the decision if they should be responded to -- and how they should be responded to -- was never very clear.

According to the second video on the right side here -- http://www.s9morecomfort.com/s9morecomf ... toset.html, thanks to the FOT obstruction identification, the autoset can start responding to an anpea the minute the obstruction is identified and the 10 second threshold is crossed.

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jnk
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Re: (UT?) S9 Reviews

Post by jnk » Mon Mar 08, 2010 8:58 am

ozij wrote:To the best of my understanding, the A10 algorithm (which is used up to and including the s8 II series) did not use obstruction indicators in hypopneas, this is the Autoset's definition (my emphasis):
Autoset clinician's manual wrote:A hypopnea is defined as a 50 to 75% drop in ventilation. A hypopnea is scored
if the 8-second moving average ventilation drops below 50%, but not below
25%, of the recent average for 10 consecutive seconds. In order to avoid falsely
responding to central hypopneas, the AutoSet algorithm does not respond to
hypopneas but rather to the associated snore or flow limitation
The S9 definition you found, jeff, hints (in my mind) that this time around Resmed's enhanced algorithm can distinguish the presence of a partial obstruction during the hypopnea. The A10 seems to have been incapable of that. If indeed the new algorithm has an improved ability to detect obstructions, the could explain the smaller number of hypopneas reported.

I felt I could never know if ResMed hypopneas were of central origin or obstructive -- and consequently, the decision if they should be responded to -- and how they should be responded to -- was never very clear.

According to the second video on the right side here -- http://www.s9morecomfort.com/s9morecomf ... toset.html, thanks to the FOT obstruction identification, the autoset can start responding to an anpea the minute the obstruction is identified and the 10 second threshold is crossed.
I assume the only way an hypopnea can be recognized as obstructive is if the algorithm can recognize the flattening of the flow curve of the flow limitation as it morphs into a hypopnea. (I'm probably not saying that very well.) I don't think FOT could discern the difference.

It also seems to me that the machine waits until breathing has resumed after an obstructive apnea before raising pressure to prevent another apnea. So it doesn't exactly attack an apnea in progress. That assumption is based partly on the lowest video on that page that shows breathing resuming before pressure increases.

But I could be wrong with both of those assumptions.

Interesting stuff.

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ozij
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Re: S9 Reviews

Post by ozij » Mon Mar 08, 2010 10:05 am

Yes, I see what you mean about the bottom most video.

The second one on the right side, in min 01:00 describes the FOT and says (about 01:20) "The algorithm compares this pressure to its flow response: if the airway is closed, there will be little or no response and fluctuations is mask pressure will be barely diminished. The algorithm will then increase treatment pressure in proprtion to the severity of the event" I took that to mean "while the event is taking place". However, you may quite right in maintaining that it starts after the event ends; Even the A10 responds in proportion to events lengths - I misinterpreted the "then".

Concerning hypopneas:
Is it unreasonable to assume the aforementioned flow and fluctuation parameters will still exists in a partial way when the airway is partially obstructed? I don't know enough physics for this, but I'm just thinking that a partially obstructed airway will cause some diminishment in in mask pressure fluctuation -- though not as much as an open one.

Of course, as could be as wrong about these things as you could....
And then we're both looking at stuff that is 50%, if not more, publicity.

O.

_________________
Mask: AirFit™ P10 Nasal Pillow CPAP Mask with Headgear
Additional Comments: Machine: Resmed AirSense10 for Her with Climateline heated hose ; alternating masks.
And now here is my secret, a very simple secret; it is only with the heart that one can see rightly, what is essential is invisible to the eye.
Antoine de Saint-Exupery

Good advice is compromised by missing data
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jnk
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Re: S9 Reviews

Post by jnk » Mon Mar 08, 2010 10:55 am

ozij wrote:Yes, I see what you mean about the bottom most video.

The second one on the right side, in min 01:00 describes the FOT and says (about 01:20) "The algorithm compares this pressure to its flow response: if the airway is closed, there will be little or no response and fluctuations is mask pressure will be barely diminished. The algorithm will then increase treatment pressure in proprtion to the severity of the event" I took that to mean "while the event is taking place". However, you may quite right in maintaining that it starts after the event ends; Even the A10 responds in proportion to events lengths - I misinterpreted the "then".

Concerning hypopneas:
Is it unreasonable to assume the aforementioned flow and fluctuation parameters will still exists in a partial way when the airway is partially obstructed? I don't know enough physics for this, but I'm just thinking that a partially obstructed airway will cause some diminishment in in mask pressure fluctuation -- though not as much as an open one.

Of course, as could be as wrong about these things as you could....
And then we're both looking at stuff that is 50%, if not more, publicity.

O.
To my way of thinking, there has always been a big difference between the words "responds to," "treats," and "attacks during." To me, a machine can be said to "respond to" something when it changes what it does some time afterward based on the fact that something happened. Similarly, if there are fewer of something when using a treatment, then the treatment "treats" that something. I think those two ways of describing a machine's operation are OFTEN misread as "attacks during." But that is nothing more than my impression, based on advertising literature, as well as my brief experience as a not-so-skillful copy editor trying to deal with words meant to fudge understanding for reasons of purposeful ambiguity.

I am not a big believer in FOT for home use yet. Maybe it will prove itself. But it hasn't for me yet. I think it might be great for a lab experiment with a known tube and mask and patient. But in the real world with the different characteristics of, say, nasal pillows versus a DreamWeaver all-cloth mask, I can't see how sensors could make heads or tails out of oscillations much of the time. That opinion of mine is not based on knowledge or understanding of any details of the application or the science--just a common-sense (or lack thereof) attempt to "get" the concept for myself. And I keep coming back to the fact that sleep labs don't use it. They use belts.

On the other hand, I think ResMed has some history in recognizing inspiratory flow limitations from the flattening of flow curves. If an algorithm responds to the flattening of a flow limitation, than it will change what it does when a hypopnea with indications of obstruction takes place (even if technically it is not responding to the hypopnea itself), because it is "responding" to the indications of obstruction, the flattening of the curve, or the obstrtuctive limitation of the flow. (Although, I may misunderstand ALL of that.) It is just that recently I have been very surprised at seeing ResMeds now giving a higher AI than HI in some of the charts being posted from S9's on this board. Looks to me like the definitions for scoring must have changed quite a bit. It would be good to know how the machine is scoring itself. And to my mind, it would be fallacy for users to jump to the conclusion that a machine is giving particularly great treatment if that judgment is based on nothing more than how the machine chooses to score its own effectiveness. To me, home-machine scores are estimates to be used for trending only. But I still want to know as much as I can about how the estimates are arrived at.

Edit: Fixed a particularly bad verb-agreement problem in the sentence before the mention of editing.
Last edited by jnk on Tue Mar 09, 2010 10:02 am, edited 1 time in total.

CPAPPRO13

Re: S9 Reviews

Post by CPAPPRO13 » Mon Mar 08, 2010 1:57 pm

50% reduction in flow for at least 10 seconds

jnk
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Re: S9 Reviews

Post by jnk » Mon Mar 08, 2010 2:09 pm

jnk wrote: . . . without a clear definition of how they now establish baseline, it doesn't say much.
"Hypopnea -- A hypopnea is an episode of shallow breathing during sleep. A hypopnea is scored when there is a reduction in breathing by 50% of baseline breathing with partial upper airway obstruction for 10 seconds or more. The event is scored after 10 seconds of the hypopnea."-- http://www.resmed.com.sg/us/assets/docu ... er_eng.pdf
The S8 scored a lot of hypopneas. Seems as if the S9 does not. My question is, What changed? And why?

CPAPPRO13

Re: S9 Reviews

Post by CPAPPRO13 » Mon Mar 08, 2010 2:12 pm

The s8 would count hypopneas after transient arousal. The s9 does not which keeps the AHI more inline with AASM standards.

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ozij
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Re: S9 Reviews

Post by ozij » Mon Mar 08, 2010 2:35 pm

And I keep coming back to the fact that sleep labs don't use it. They use belts.
No auto uses belts.
All auto algorithm designers have to figure out how to refrain from raising pressure when a person has just stopped breathing, but their airway is open.

All of them.

If identifying an oper airway is based on flow (does it or does it not) and fluctuation (is it or is it not) I don't see why the mask type should cause problems. It's a state difference between Sata A and State B -- on the same mask.

But if they do -- you can alway try to stick to ResMed masks.
O.

_________________
Mask: AirFit™ P10 Nasal Pillow CPAP Mask with Headgear
Additional Comments: Machine: Resmed AirSense10 for Her with Climateline heated hose ; alternating masks.
And now here is my secret, a very simple secret; it is only with the heart that one can see rightly, what is essential is invisible to the eye.
Antoine de Saint-Exupery

Good advice is compromised by missing data
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jnk
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Re: S9 Reviews

Post by jnk » Mon Mar 08, 2010 2:36 pm

CPAPPRO13 wrote:The s8 would count hypopneas after transient arousal. The s9 does not which keeps the AHI more inline with AASM standards.


No.

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dsm
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Re: S9 Reviews

Post by dsm » Mon Mar 08, 2010 2:51 pm

jnk wrote:
ozij wrote:Yes, I see what you mean about the bottom most video.

The second one on the right side, in min 01:00 describes the FOT and says (about 01:20) "The algorithm compares this pressure to its flow response: if the airway is closed, there will be little or no response and fluctuations is mask pressure will be barely diminished. The algorithm will then increase treatment pressure in proprtion to the severity of the event" I took that to mean "while the event is taking place". However, you may quite right in maintaining that it starts after the event ends; Even the A10 responds in proportion to events lengths - I misinterpreted the "then".

Concerning hypopneas:
Is it unreasonable to assume the aforementioned flow and fluctuation parameters will still exists in a partial way when the airway is partially obstructed? I don't know enough physics for this, but I'm just thinking that a partially obstructed airway will cause some diminishment in in mask pressure fluctuation -- though not as much as an open one.

Of course, as could be as wrong about these things as you could....
And then we're both looking at stuff that is 50%, if not more, publicity.

O.
To my way of thinking, there has always been a big difference between the words "responds to," "treats," and "attacks during." To me, a machine can be said to "respond to" something when it changes what it does some time afterward based on the fact that something happened. Similarly, if there are fewer of something when using a treatment, then the treatment "treats" that something. I think those two ways of describing a machine's operation is OFTEN misread as "attacks during." But that is nothing more than my impression, based on advertising literature, as well as my brief experience as a not-so-skillful copy editor trying to deal with words meant to fudge understanding for reasons of purposeful ambiguity.

I am not a big believer in FOT for home use yet. Maybe it will prove itself. But it hasn't for me yet. I think it might be great for a lab experiment with a known tube and mask and patient. But in the real world with the different characteristics of, say, nasal pillows versus a DreamWeaver all-cloth mask, I can't see how sensors could make heads or tails out of oscillations much of the time. That opinion of mine is not based on knowledge or understanding of any details of the application or the science--just a common-sense (or lack thereof) attempt to "get" the concept for myself. And I keep coming back to the fact that sleep labs don't use it. They use belts.

On the other hand, I think ResMed has some history in recognizing inspiratory flow limitations from the flattening of flow curves. If an algorithm responds to the flattening of a flow limitation, than it will change what it does when a hypopnea with indications of obstruction takes place (even if technically it is not responding to the hypopnea itself), because it is "responding" to the indications of obstruction, the flattening of the curve, or the obstrtuctive limitation of the flow. (Although, I may misunderstand ALL of that.) It is just that recently I have been very surprised at seeing ResMeds now giving a higher AI than HI in some of the charts being posted from S9's on this board. Looks to me like the definitions for scoring must have changed quite a bit. It would be good to know how the machine is scoring itself. And to my mind, it would be fallacy for users to jump to the conclusion that a machine is giving particularly great treatment if that judgment is based on nothing more than how the machine chooses to score its own effectiveness. To me, home-machine scores are estimates to be used for trending only. But I still want to know as much as I can about how the estimates are arrived at.
Ozij & jnk,

Just to add another 0.2 c worth of evaluation - what I am seeing & hearing from the videos is that the response to obstructive apneas can be interpreted 2 ways.

1) In one of the earlier videos they state (assuming the words were chosen specifically) "the patient must arouse and restore the upper airway tone to begin breathing normally again" - assuming each word was carefully selected, then the word 'must' tells us that the arousal must happen in order 'to restore the upper airway tone" - this then seems to signal the end of the OSA event.

2) As soon as an hypopnea (or zero flow) is detected, the machine appears to allow 5 secs to pass, then the machine commences a 4 Hz FOT burst for 10 secs - the machine looks at the flow curve of the flow & if the airway is open it will see a particular flow curve ve a quite different flow curve if the airway is heavily restricted (hypopnea) or blocked (zero flow apnea).

One interpretation is ...
If the patient recovers (has an arousal) before 15 secs have passed then the patient will have cleared the event and the machine resumes normal operation (probably turns off FOT & FOT response sampling before the normal 10 secs of FOT pulse have elapsed). If after 15 secs the patient hasn't resumed normal breathing (OSA event) then the machine responds with increased pressure & begins another 5 sec period of sampling the flow curve (and if obstruction detected, sends another 10 secs of FOT etc: etc: )

There appears to be no reason why the machine shouldn't increase pressure during an overly long OSA event. Previously that was a no-no because of the harm done if the patient was a central sufferer & adding pressure tended to create more centrals.

DSM

#2 Just saw DreamDivers charts & they appear to confirm 2 above plus the 15 secs duration (5 secs wait then 10 secs FOT)
viewtopic/t49956/Using-the-S9-Autoset-w ... iated.html
Last edited by dsm on Mon Mar 08, 2010 3:20 pm, edited 1 time in total.
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jnk
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Re: S9 Reviews

Post by jnk » Mon Mar 08, 2010 3:00 pm

ozij wrote:
And I keep coming back to the fact that sleep labs don't use it. They use belts.
No auto uses belts.
So they use something with less ability to differentiate. I am wondering how much less ability to differentiate, in practice. Will they do anything to prove to the public and doctors how well their application of the technique works in the real world? Or is everyone just supposed to swallow their claims, like so much highly-pressurized air? Until then, I'm trying to prevent my developing advertising aerophagia!
ozij wrote: All auto algorithm designers have to figure out how to refrain from raising pressure when a person has just stopped breathing, but their airway is open.

All of them.
I think they have to figure out a way to decide whether to raise pressure after the apnea is over in order to figure out whether that would help prevent another apnea or not. Yes. A10 seemed to have a good approach to me.
ozij wrote:If identifying an oper airway is based on flow (does it or does it not) and fluctuation (is it or is it not) I don't see why the mask type should cause problems. It's a state difference between Sata A and State B -- on the same mask.
Yes. Fluctuation is my concern. If the machine attempts to assess the state of the airway based on the magnitude of the reactions to the pressure oscillations it generates (which may be a statement that reflects my misunderstanding of how it does what it does), then it seems to me that different masks could react differently to those oscillations as far as absorbing them or magnifying them. Some masks would, I assume, tend to inflate and deflate in response to the oscillations, for example. The flow stops either way, open or closed airway. So it has to be about sensing differences in how the pressure vibrations, or fluctuations, affect the machine's sensors, and I am wondering how different masks would affect that. My mind is not very scientific, though. So I guess it all works. At this point, for me, until I understand it better, this latest advancement in technology seems indistinguishable from magic. I can be slow that way.
ozij wrote:But if they do -- you can alway try to stick to ResMed masks.
O.
Well, that would depend on price, for me. I want to be convinced of the technology. I want to believe. Truly I do.

ResMed, help me have more faith!

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dsm
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Re: S9 Reviews

Post by dsm » Mon Mar 08, 2010 6:30 pm

jnk wrote:
ozij wrote:
And I keep coming back to the fact that sleep labs don't use it. They use belts.
No auto uses belts.
So they use something with less ability to differentiate. I am wondering how much less ability to differentiate, in practice. Will they do anything to prove to the public and doctors how well their application of the technique works in the real world? Or is everyone just supposed to swallow their claims, like so much highly-pressurized air? Until then, I'm trying to prevent my developing advertising aerophagia!
ozij wrote: All auto algorithm designers have to figure out how to refrain from raising pressure when a person has just stopped breathing, but their airway is open.

All of them.
I think they have to figure out a way to decide whether to raise pressure after the apnea is over in order to figure out whether that would help prevent another apnea or not. Yes. A10 seemed to have a good approach to me.
ozij wrote:If identifying an oper airway is based on flow (does it or does it not) and fluctuation (is it or is it not) I don't see why the mask type should cause problems. It's a state difference between Sata A and State B -- on the same mask.
Yes. Fluctuation is my concern. If the machine attempts to assess the state of the airway based on the magnitude of the reactions to the pressure oscillations it generates (which may be a statement that reflects my misunderstanding of how it does what it does), then it seems to me that different masks could react differently to those oscillations as far as absorbing them or magnifying them. Some masks would, I assume, tend to inflate and deflate in response to the oscillations, for example. The flow stops either way, open or closed airway. So it has to be about sensing differences in how the pressure vibrations, or fluctuations, affect the machine's sensors, and I am wondering how different masks would affect that. My mind is not very scientific, though. So I guess it all works. At this point, for me, until I understand it better, this latest advancement in technology seems indistinguishable from magic. I can be slow that way.
ozij wrote:But if they do -- you can alway try to stick to ResMed masks.
O.
Well, that would depend on price, for me. I want to be convinced of the technology. I want to believe. Truly I do.

ResMed, help me have more faith!
JNK

I am going to be blunt & say that DreamDiver's reality far exceeds your comments and theory about a machine you don't have & haven't tried.
I am amused at the extent of the critical analysis of the S9 by someone who is in reality describing a phantom and who has no need to buy
the new machine anyway. But keep it coming. It is insightful in other ways



DSM
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jnk
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Re: S9 Reviews

Post by jnk » Mon Mar 08, 2010 7:03 pm

dsm wrote:JNK

I am going to be blunt & say that DreamDiver's reality far exceeds your comments and theory about a machine you don't have & haven't tried.
I am amused at the extent of the critical analysis of the S9 by someone who is in reality describing a phantom and who has no need to buy
the new machine anyway. But keep it coming. It is insightful in other ways



DSM
Cool. So if we're being blunt, I'll just say that I have no idea what you are talking about or how it relates even remotely to my post.

But it was nice hearing from you.



jeff