POLL: Typical AHI for ResMed Users

[carbonman]

If I understand correctly, and please correct if not.....

does not my S8 data show exactly what you guys are talking about.
I have never had the S8 respond like the Mseries does.
This would be due to the 10cm(h2o implied) rule????

Isn't the response difference what we see in this Mseries data??



It is my hypothisis...or carbothisis, that this is why I am sleeping better and
FEELING better since I started using the S8. Less probing or pre-emptive searching and
less disturbances due to radical pressure changes.

[billbolton]

ResMed assumes that apneas above 10 are central, and will not respond to them.

This has been done to death here numerous times already... that is NOT the case at all!

[ozij]

ResMed assumes that apneas above 10 are central, and will not respond to them.

This has been done to death here numerous times already...

How very true.

And how very wrong to say that is not the case at all.... I assume Michael Brethon-Jones who invented the Autoset algorithm knows what he is talking about.

http://www.resmed.com/au/assets/documen ... 0906r1.pdf

On the other hand, the vast majority of obstructive apneas are already well controlled by 10 cmH2O, and we are only fine tuning using snoring and flattening. So it is a pretty good bet that if the pressure is already above 10 cmH2O, any apneas are most likely central, and you should leave them alone (except in patients with central apneas due to heart failure). But if the pressure is below 10 cmH2O, most apneas will be obstructive and you should put the
pressure up. There’s nothing magical about 10 cmH2O, it’s just a good place to put the line in the sand

(my emphasis).

[ozij]

If I understand correctly, and please correct if not.....

does not my S8 data show exactly what you guys are talking about.
I have never had the S8 respond like the Mseries does.
This would be due to the 10cm(h2o implied) rule????

The ResScan graph condenses the distance between 7 and 14 cms so much that I can't see what is happening to the pressure in response to your events. It doesn't show your snores, or flow limitation -- so its very difficult to tell what it is and what it is not responding to in your breathing.

The most important thing is that the ResMed algorithm is giving you (I quote, loosely) "the best therapy ever" -- which means you belong to the large group that algorithm is good for. Even excellent for.

No algorithm is good for 100% of the population. None.

Howerver, the issue of this thread is the residual HI reported by ResMed, in contrast to Respironics, not the response to Apneas, and I really would not like it to move to another A10 discussion.

jeff (jnk) has reminded us that ResMed makes a big effort to pre-empt events, and uses a logic different from Respironics'.

In the context of the original topic -- ResMed's higher report of residual H's, Muff*'s following statements, with all their "may"s (all added emphasis mine), make sense to me:

In summary:

Variable Breathing may be a reliable marker of poor sleep quality.

The exclusionary capability of the Variable Breathing Mode may make the Respironics algorithm more accurate in determining SDB events over the entire sleep period in that wake events may be ignored.

Intractable HI in ResMed A10 results may, in some patients, be a result of wake phenomena. In these cases, while an arbitrary "correction factor" may be applied, the first thing that should be examined is Sleep Efficiency.

Extraordinary high ResMed HI, however, should not be summarily dismissed under any circumstances.

Extraordinary high ResMed HI, however, should not be summarily dismissed under any circumstances.

The last last part seems obvious to me. While the first thing that one would think if using ResMed would be that the residual events are undertreated obstructive events, I would move that to #4 on the list, given the aforementioned aggressive nature of the A10 HI algorithm (and assuming you're using relatively free-range parameters). If it works, then there won't be any residual events.

#2 would be that the events have a central flavor, and if one is fortunate to have access to Respironics HI, and it is significantly lower, then the Respironics algorithm has discarded them under it's central criteria;

#3 would be that there is fixed obstruction, a subject that has been effectively covered in the past, most notably in the GK420E IFL1 threads with mountainwoman, rested gal, and somebody else who seems to escape me at the moment.

Muffy

O.

[billbolton]

And how very wrong to say that is not the case at all....

The current Resmed APAP algorithm implemented in S8 flow generators is not the same as that in use, over 7 years ago, when the article you quote was published.

Again, this has been discussed here many times!

[ozij]

And how very wrong to say that is not the case at all....

The current Resmed APAP algorithm implemented in S8 flow generators is not the same as that in use, over 7 years ago, when the article you quote was published.

Again, this has been discussed here many times!

Really? You must know something Resmed does not. An as usual, you do not share your sources.

posting.php?mode=quote&f=1&p=257367

On April 6 2008 I coincidentally ran into the following, from Sept. 2005.

viewtopic.php?p=37380#37380

Posted: Wed Sep 07, 2005 10:35 pm Post subject: ResMed S8 Vantage EPR

I called ResMed to see if they could give me some information regarding this new device but, as it is not yet launched, their answer was "nyet."

Specifically, I wanted to know:
1) Is the algorithm running this machine is the same as that which runs the Spirit?
2) Can the Expiratory Pressure Relief be disabled if the user finds it to be unhelpful?
3) Can the machine can be set to function in straight CPAP mode if desired?
4) Does the machine record/provide data for software analysis?

Two days later a reply was received:
viewtopic.php?p=37575#37575

Posted: Fri Sep 09, 2005 12:55 am Post subject: ResMed replys

Following answers came to me from ResMed Worldwide HQ in Sydney.
*******************************************************

I would be most grateful if someone could answer these particular questions
for me ...

1) Is the algorithm running this machine is the same as that which runs the
Spirit?

>>Same. It's the hardware only that is different.<<

2) Does the S8 offer a feature called Expiratory Pressure Relief ?

>>YES<<

3) If yes, can the Expiratory Pressure Relief be disabled if the user finds
it to be unhelpful?

>>YES, ERP is only available in CPAP mode and can be disabled if not required.<<

4) Can the S8 Autoset machine can be set to function in straight CPAP mode
if desired?

>>YES<<

5) Does the S8 Autoset machine record/provide data for software analysis?
(I have seen that the S8s can use a datacard that appears slightly larger
than a memstick, what information is put on the datacard & can I buy that software and the required reader to analyse the data)

>>YES, up to 180 sessions of usage, pressure, leak and events data as well as 5 nights of detailed data (Night Profile). The software and datacard already can be purchased from ResMed.<<

Cheers

DSM

UPDATE# corrected typo in ans to Q5 (typo was in the reply as sent)

I suggest you supply reliable links, Bill, instead of making faces. I am always happy to learn from reliable sources, and have done my best to find them and share them.


I will only return to this subject when I see a link to a ResMed document, showing the change in the A10 algorithm.

If you want have the final word by making another unsupported erroneous statement Bill, go ahead and do it. Readers can think for themselves.
O.

[jnk]

Can anyone here explain the following to me (from the article Muffy linked to earlier in the thread)? Is this implying that all the units have the same basic line in the sand that ResMed keeps getting picked on for having? (Colorization is mine.)

"Apnea. All devices exhibited pressure response to the change from normal to apneic breathing (Figure 1). The SleepStyle 220 (Fisher & Paykel), Sandman (Covidien), and S8 units (ResMed) rapidly responded to the apnea pattern, achieving the 10 cm H2O default apnea cap programmed for these units within 5 minutes of the apnea pattern starting; the REMstar unit achieved 10 cm H2O within 10 minutes. The SleepStyle 200, Sandman, and S8 units all increased pressure above 10 cm H2O, suggesting a pressure response to other nonapneic events present in the signal."
--http://www.rtmagazine.com/issues/articl ... -08_05.asp

[carbonman]

The ResScan graph condenses the distance between 7 and 14 cms so much that I can't see what is happening to the pressure in response to your events. It doesn't show your snores, or flow limitation -- so its very difficult to tell what it is and what it is not responding to in your breathing.

One of the draw backs to ResScan and a positive for EncorePro.
However, if you look at the statistics page the pressure never changes
more that 1.4cm. That is very typical for most nights.

Once again, my point, there are not radical pressure changes in response to any kind of event.

The most important thing is that the ResMed algorithm is giving you (I quote, loosely) "the best therapy ever" -- which means you belong to the large group that algorithm is good for. Even excellent for.

Yes, it is good for me.

However, the issue of this thread is the residual HI reported by ResMed, in contrast to Respironics, not the response to Apneas.

Point taken, I thought I was talking about HI reported.

In that light, the avg. AI and HI and AHI for the 532 hours/61days I have been using the S8:
AI 0.1 HI 2.8 AHI 2.9
These are the reported numbers.
Even before divide by 2, I am pleased w/numbers like this.
Divide by 2..........I'll take those numbers any night, w/any machine.

Be kind.

[ozij]

Can anyone here explain the following to me (from the article Muffy linked to earlier in the thread)? Is this implying that all the units have the same basic line in the sand that ResMed keeps getting picked on for having? (Colorization is mine.)

Resmed does not get picked on. It has been stated time and again -- by "-SWS" for instance -- that all algorithms have a line in the sand.
Epidemiological data shows that apneas appearing above 10 are frequently central apneas -- the kind that will not respond to a raise in pressure. Therefore, all companies set up rules for handling apneas that appear above a certain pressure.

Puritan Bennet's Sandman lets the user move the line in the sand upward or downwards -- the default is 10. (On my machine it is presently 8.5, because that's the way I set it). On the graph, you can see the Sandman frozen at 10 cm/H2O.

Respironics' Remstar has it's NR algorithm, that kicks in, in the APAP, as follows: "Above 8 cm/H2O pressure, the pressure increase for sustained apneas/hypopneas is limited to 3 cm/H2O above the pressure setting at the onset of the apnea/hypopnea sequence". Note that "The pressure 3 cmH2O above the Onset Pressure is called the NRAH Threshold". (Non Resonsive Apnea Hypopnea threshold) If apnea onset is at 15, Respironics' maximal non-responsive apnea hypopnea threshold (i.e. line in the sand) will be 18. (The lowest pressure for the NR algorithm to kick in, in the Auto Bipap is 10, for IPAP).
Respironics' NRAH algorithm on the Remstar and M-Series is actually an "un oh, we goofed" policy, since once a series of apneas is defined as "non-responsive" the algorithm drops its pressure, and waits -- the drop is clearly visible in the graph which shows Respironic handling a series of inherently non-responsive apneas, starting at the minimum pressure. The events generated by machine, are not responding to its therapy, so after reaching the NRAH (at 11)the Respironics drops it pressure,to 9 as it is meant to do.

Resmed's S8 line in the sand is drawn once and for all and nothing moves it. Resmed's policy is to make sure there will never be pressure applied to apneas without precursors, if those apnea appear above 10. The apnea delivered by the mechanical device (again and again) does have some flow limitations and the Resmed is hovering about 10 and a bit more -- again, as expected, since the flow limitations drive it up, the apnea itself does not.

All three machines have good results in treating the majority of people. There are outliers in the population for all three - and when they have problems on one of the algorithms, we analyse them.

Now, can someone please explain why any time the ResMed A10 gets mentioned, a number of Resmed users get so defensive that they ignore the fact that creating an auto algorithm is a complex issue? The only member who ever blatantly picked on the Resmed in rude words has been dead for 9 months -- it really is time to stop treating the issue a if it were a bone for dogs to fight about. If we try hard, most of us do have a capacity to behaving like rational human beings.

I'll repeat: All automatic machines have rules about handling apneas when the pressure goes above 10 cms/H2O. They do it differently, and they all fail a small group of patients.

Resmed has the A10 rule in its Autoset algorithm - and algorithm invented years ago, which was good enough for them to carry it on to the S8 and the S8 II series. Their improvemnents for the S8 II have to with adding Easy-Breathe. Resprionics' older series machine (Remstar and M Series) had the NRAH -- they clearly found it insufficient when they created the new PR algorithm - since they now attempt to identify central apnea with the forced oscillation technique. Sandman machines still let the user decide where to place the line in the sand.

If we don't discuss the algorithm differences and their implications, we will be doing a disservice to all machine users, and to our forum.


O.

[billbolton]

ResMed assumes that apneas above 10 are central, and will not respond to them.

Resmed's policy is to make sure there will never be pressure applied to apneas without precursors, if those apnea appear above 10.

[ozij]

The ResScan graph condenses the distance between 7 and 14 cms so much that I can't see what is happening to the pressure in response to your events. It doesn't show your snores, or flow limitation -- so its very difficult to tell what it is and what it is not responding to in your breathing.

One of the draw backs to ResScan and a positive for EncorePro.
However, if you look at the statistics page the pressure never changes
more that 1.4cm. That is very typical for most nights.

Once again, my point, there are not radical pressure changes in response to any kind of event.

A very good point, showing how the Resmed is giving you great theapy with its approach to your flow limitations and snores - the very things it considers precursors to apneas, and responds to at any level.

Be kind

I do hope that's one of your general philosophical statements, and not a reaction to how you experienced my response....

O.

[carbonman]

Thank you for your response.

Be kind

and not a reaction to how you experienced my response....O.

Correctly perceived.
I'm just a pup.
I'm willing to push the envelope
but respectful of the boundaries.

[jnk]

O.,

I don't mean to be paranoid about it. I just find it ironic that if ALL APAPs now have a "10 cm H2O default apnea cap," as the article seems to state, still the times that cap most often gets mentioned around here is in connection with warning people off the one brand that actually exceeded the cap in that test (even approaching 11.5 cm, ResMed apparently finding precursors in that signal no other brand did) and pushing people toward the brand that responded with the least pressure! Am I the only one that finds that absolutely hilarious?

But I tend to find humor in odd places. Like, for example, carbonman, the author of the "2x4" and "you-might-be-braindead" threads, saying something like "be kind" to you. Now THAT'S irony. I can say that because you are two of my favorite posters and I consider you both two of the kindest people I know. And I mean that. (I saw what he meant, that he was expressing respect, but I found humor in it anyway. I'm bad that way.)

Very educational post, ozij. Thanks!

jeff

[-SWS]

Carbonman, thanks for submitting those charts. I agree that the Respironics pressure probes may what doesn't suit you. By contrast your Resmed pressure response more closely approaches CPAP therapy at right around 12 cm. One interesting experiment thus might be to compare your residual AHI and subjective assessment using A10 with that of a few experimental fixed pressures between 11 cm and 13 cm.

I don't mean to be paranoid about it. I just find it ironic that if ALL APAPs now have a "10 cm H2O default apnea cap," as the article seems to state

Jeff, despite the poor way that article's author worded that, all APAPs do not have a "10 cm H2O default apnea cap".

still the times that cap most often gets mentioned around here is in connection with warning people off the one brand that actually exceeded the capin that test (even approaching 11.5 cm, ResMed apparently finding precursors in that signal no other brand did) and pushing people toward the brand that responded with the least pressure! Am I the only one that finds that absolutely hilarious?

I personally find it entirely disappointing that the Resmed Defensive Knee Dancers repeatedly interject that same reproach in threads like this---where people are NOT engaged in that particular behavior.

Where are the Defensive Knee Dancers for the other brands? By comparison they rarely show with those same defensive "sports-team fandom" behavioral dynamics. Complain about Respironics NRAH logic---as it directly pressure-responds to apneas above 10 cm----and soccer-cup rivalry dynamics tend not to occur. Complain about PB/Tyco's IFL1 trigger over-responding for some patients, and again those same team-fandom psychological dynamics tend not to occur.

Talk about apnea as a Resmed control-logic "trigger event" above and below 10 cm, and the Resmed Knee Dancing Troupe shows up to displace that apnea "trigger event" discussion with reproach about overall preemptive apnea treatment above 10 cm. Every other algorithm is allowed to have frank discussion about strengths, weaknesses, and control-logic nuances without that brand's loyally over-defensive knee dancers showing up to argumentatively suppress or redirect that discussion.

From my perspective, good Resmed control-logic discussions get repeatedly displaced by overall preemptive discussion of how well Resmed preempts apneas above 10 cm using precursor signals. Here's an interesting possibility: How about saving the reproach and conversational redirection for those threads in which verbal A10 infractions actually DO occur, guys? That way people who want to talk about the control logic nuances of all the algorithms won't have to repeatedly receive reproach and harping about what happened in past threads when they want to rationally describe apneas as a control-logic trigger event both above and below 10cm.

Alternately, we can continue to have one and only one control-logic taboo subject on this message board----that taboo "trigger event" subject the Resmed Knee Dancers continue to displace with reminders of just how well the snore and flow-limitation control-logic triggers work for A10 above 10cm...

[jnk]

. . . I personally find it entirely disappointing that the Resmed Defensive Knee Dancers repeatedly interject that same reproach in threads like this---where people are NOT engaged in that particular behavior.

Where are the Defensive Knee Dancers for the other brands? By comparison they rarely show with those same defensive "sports-team fandom" behavioral dynamics. Complain about Respironics NRAH logic---as it directly pressure-responds to apneas above 10 cm----and soccer-cup rivalry dynamics tend not to occur. Complain about PB/Tyco's IFL1 trigger over-responding for some patients, and again those same team-fandom psychological dynamics tend not to occur.

Talk about apnea as a Resmed control-logic "trigger event" above and below 10 cm, and the Resmed Knee Dancing Troupe shows up to displace that apnea "trigger event" discussion with reproach about overall preemptive apnea treatment above 10 cm. Every other algorithm is allowed to have frank discussion about strengths, weaknesses, and control-logic nuances without that brand's loyally over-defensive knee dancers showing up to argumentatively suppress or redirect that discussion.

From my perspective, good Resmed control-logic discussions get repeatedly displaced by overall preemptive discussion of how well Resmed preempts apneas above 10 cm using precursor signals. Here's an interesting possibility: How about saving the reproach and conversational redirection for those threads in which verbal A10 infractions actually DO occur, guys? That way people who want to talk about the control logic nuances of all the algorithms won't have to repeatedly receive reproach and harping about what happened in past threads when they want to rationally describe apneas as a control-logic trigger event both above and below 10cm.

Alternately, we can continue to have one and only one control-logic taboo subject on this message board----that taboo "trigger event" subject the Resmed Knee Dancers continue to displace with reminders of just how well the snore and flow-limitation control-logic triggers work for A10 above 10cm...

Sorry, -SWS. Point taken. It won't happen again. I've been misbehaving all week. I think it has something to do with 9-11 approaching.

I am still trying to understand the chart, though. If I understand what it shows (and I realize I likely do not), it looks to me like apneas were "faked" to those machines for 30 minutes straight to see what they would do. And it looks to me like they all acted pretty much the same, didn't they? Which I take as good, myself. Of ALL the brands. It looks to me like once they hit around the 10 cm mark, in that chart, they all stopped raising pressure even though the apneas continued for another 20 or 25 minutes. Whatever the algorithms say, that looks like what they did with the fake apneas. But I may be misreading the chart somehow.

So am I understanding what I'm being taught in that they all would have acted very differently if they had been set at 11 cm as their minimum then had fake apneas thrown at them? Some would have raised higher while others would not?

Please forgive me, -SWS. My friend fishhead once gave me a coffee mug that said "#1 Jerk" on it as a gift. I earned it. I still have it. He still loves me though.

On my best behavior now.

jeff