ResScan UnderReporting or SmartLink OverReporting or ?

[ozij]

I wonder if anyone has ever done a sleep study using these machines and compared the manually scored AHI to the machine-generated one (assuming that the flow rate measurement on them is accurate enough for PSG)? This would seem to me to be the best way to calibrate the algorithm.

The studies have been attempted, and were referenced by me previously in this thread, see my posts on the first pages. As Bill Bolton noted in the beginnig of this thread, there have been many discussions of the way these machine report and respond. These kinds of studies are done constantly -- both in vivo and in vitro - and the worth of both types of studies has been discussed as well.

Since this thread is really about "oh how terrible those money grubbing companies are" - or possibly about "oh how useless a machine's AHI data" and not about understanding the true differences between machines, I am not at all surprised that the following points have not been addressed in the reported, fixed pressure comparison:

• Which pressure was chosen for the reported comparison - there is a large discrepancy in the pressures arrived at in auto mode by those machines - so how was the comparison pressure decided upon?
  

  Sep 27/28 - 4.0 (IP)
  Sep 28/29 - 8.0 (IP)
  Sep 29/30 - 9.1 (S9)
  Sep 30/Oct 01 - 8.9 (S9)
  Oct 02/03 - 9.9 (S9)
  Oct 03/04 - 9.6 (S9)
  Oct 04/05 - 7.5 (IP)
  Oct 05/06 - 7.5 (IP)
  Oct 06/07 - 7.0 (IP)
  Oct 07/08 - 6.5 (IP)
  Oct 08/09 - 7.0 (IP)
  Oct 09/10 - 9.9 (S9)
  Oct 10/11 - 10.2 (S9)
  Oct 11/12 - 9.6 (S9)

  Note the original AHI discrepancy
  And compare the AHI difference reported, at an unknown fixed pressure:
  

  Oct 14/15 - AHI 0.2 (ResMed S9 AutoSet w/ResScan 3.11)
  Oct 15/16 - AHI 2.98 (DeVilbill IntelliPAP w/SmartLink 2.1)
  Oct 16/17 - AHI 3.47 (IntelliPAP)
  Oct 17/18 - AHI 0.5 (S9)

  This is the same AHI difference reported originally, viewtopic/t56345/viewtopic.php?p=528190#p528190[u] despite the fact the the pressure of one machine had been changed for this comparison[/u]. Intriguing, and thought provoking, to say the least. It implies that for the OP's breathing pattern, pressure does not affect the AHI reported by one of these machines. We don't know which, and reverse comparison was not tried either. A singular lack of curiousity.
• We are never shown comparative charts of what the sofware reports for the same time period. Another indication of what this thread is really about.
• Information about the manometer used as a standard for calibrating the machines' pressure before running this comparison. Wouldn't you expect a person who repeatedly points out the importance of standards to make sure he uses one when running his own "experiment". And don't tell me a data inclined sceptic of AHI has suddenly become a believer of reported pressure.
• Information about the level of pressure relief (Flex, EPR)used on either machine for the comparison; unlike the older DeVilbiss firmware, the newer one has a Flex option.
• Information about the settings used on the DeVilbiss to define events - these can be changed by the user.

The following is true for anyone reading this thread and wondering about the true value of the data reported by machines:

• The machine to use is the machine that helps you feel better. (Yes, I realise some people can't use the way they feel. And I realise that for some of us life can very very tough, furstrating and disappointing).
• The best way to decide which machine gives you the better therapy is to try it. FWIW, I rented a DeVilbiss before I tried a ResMed. I stopped using using the DeVilbiss before the trial period was over. But that is only me, Emilia is having a great time using a DeVilbiss. You can learn from her experience as much as you can learn from mine.
• If you have a machine that does not at all change the reported AHI no matter what pressure it is at then you can't use its data to improve your therapy.
• If you have many machines all of which do not at all change the reported AHI not matter what the pressure, then you are an exception, and you may have a tougher time otimizing your therapy.

[jonquiljo]

A singular lack of curiousity.

Whoa! Wait a minute! What's with all the emotion here? What I am seeing in your post is a lot of anger. Anger at what?

In no instance has DHC said that this is information that he/she was preparing for peer reviewed publication. Your critique would be harsh even if it was presented for a peer reviewed journal. All DHC was doing is trying to present is anecdotal data that would raise a lot of questions in any open minded person. It has been presented in a friendly and curious way - if anything, others (including myself) have been making statements as to it's possible meaning, not DHC.

Quite honestly I see no reason for rebuttal of your statements here - because you are criticizing data presented way beyond it's original intent. In fact all I see DHC saying about this at all is that they wondered why there was no standard for the reporting metrics of these machines. That is a good question - even without the data - that is - unless you have a vested interest in any of this! After almost 8000 posts, I would expect that you of all people would cut someone some room for a courteous discussion.

DHC has done nothing wrong! Stop acting as if he/she is trying to make this into more than it is. What I see is an honest and reasonable attempt to make sense out of what we see and talk about every day. This is a self-help board, not the National Academy of Sciences. Why you insist in acting as if it is - goes way too far .....

[ozij]

This is a self-help board, not the National Academy of Sciences. Why you insist in acting as if it is - goes way too far .....

<snip>
The following is true for anyone reading this thread and wondering about the true value of the data reported by machines:

• The machine to use is the machine that helps you feel better. (Yes, I realise some people can't use the way they feel. And I realise that for some of us life can very very tough, furstrating and disappointing).
• The best way to decide which machine gives you the better therapy is to try it. FWIW, I rented a DeVilbiss before I tried a ResMed. I stopped using using the DeVilbiss before the trial period was over. But that is only me, Emilia is having a great time using a DeVilbiss. You can learn from her experience as much as you can learn from mine.
• If you have a machine that does not at all change the reported AHI no matter what pressure it is at then you can't use its data to improve your therapy.
• If you have many machines all of which do not at all change the reported AHI not matter what the pressure, then you are an exception, and you may have a tougher time otimizing your therapy.

[jnk]

Personally, I would consider it a mistake ever to confuse Ozij's directness with "anger."

This stuff matters.

[DHC]

I wonder if anyone has ever done a sleep study using these machines and compared the manually scored AHI to the machine-generated one (assuming that the flow rate measurement on them is accurate enough for PSG)? This would seem to me to be the best way to calibrate the algorithm.

The studies have been attempted, and were referenced by me previously in this thread, see my posts on the first pages. As Bill Bolton noted in the beginnig of this thread, there have been many discussions of the way these machine report and respond. These kinds of studies are done constantly -- both in vivo and in vitro - and the worth of both types of studies has been discussed as well.

Since this thread is really about "oh how terrible those money grubbing companies are" - or possibly about "oh how useless a machine's AHI data" and not about understanding the true differences between machines, I am not at all surprised that the following points have not been addressed in the reported, fixed pressure comparison:

• Which pressure was chosen for the reported comparison - there is a large discrepancy in the pressures arrived at in auto mode by those machines - so how was the comparison pressure decided upon?
  

  Sep 27/28 - 4.0 (IP)
  Sep 28/29 - 8.0 (IP)
  Sep 29/30 - 9.1 (S9)
  Sep 30/Oct 01 - 8.9 (S9)
  Oct 02/03 - 9.9 (S9)
  Oct 03/04 - 9.6 (S9)
  Oct 04/05 - 7.5 (IP)
  Oct 05/06 - 7.5 (IP)
  Oct 06/07 - 7.0 (IP)
  Oct 07/08 - 6.5 (IP)
  Oct 08/09 - 7.0 (IP)
  Oct 09/10 - 9.9 (S9)
  Oct 10/11 - 10.2 (S9)
  Oct 11/12 - 9.6 (S9)

  Note the original AHI discrepancy
  And compare the AHI difference reported, at an unknown fixed pressure:
  

  Oct 14/15 - AHI 0.2 (ResMed S9 AutoSet w/ResScan 3.11)
  Oct 15/16 - AHI 2.98 (DeVilbill IntelliPAP w/SmartLink 2.1)
  Oct 16/17 - AHI 3.47 (IntelliPAP)
  Oct 17/18 - AHI 0.5 (S9)

  This is the same AHI difference reported originally, viewtopic/t56345/viewtopic.php?p=528190#p528190[u] despite the fact the the pressure of one machine had been changed for this comparison[/u]. Intriguing, and thought provoking, to say the least. It implies that for the OP's breathing pattern, pressure does not affect the AHI reported by one of these machines. We don't know which, and reverse comparison was not tried either. A singular lack of curiousity.
• We are never shown comparative charts of what the sofware reports for the same time period. Another indication of what this thread is really about.
• Information about the manometer used as a standard for calibrating the machines' pressure before running this comparison. Wouldn't you expect a person who repeatedly points out the importance of standards to make sure he uses one when running his own "experiment". And don't tell me a data inclined sceptic of AHI has suddenly become a believer of reported pressure.
• Information about the level of pressure relief (Flex, EPR)used on either machine for the comparison; unlike the older DeVilbiss firmware, the newer one has a Flex option.
• Information about the settings used on the DeVilbiss to define events - these can be changed by the user.

The following is true for anyone reading this thread and wondering about the true value of the data reported by machines:

• The machine to use is the machine that helps you feel better. (Yes, I realise some people can't use the way they feel. And I realise that for some of us life can very very tough, furstrating and disappointing).
• The best way to decide which machine gives you the better therapy is to try it. FWIW, I rented a DeVilbiss before I tried a ResMed. I stopped using using the DeVilbiss before the trial period was over. But that is only me, Emilia is having a great time using a DeVilbiss. You can learn from her experience as much as you can learn from mine.
• If you have a machine that does not at all change the reported AHI no matter what pressure it is at then you can't use its data to improve your therapy.
• If you have many machines all of which do not at all change the reported AHI not matter what the pressure, then you are an exception, and you may have a tougher time otimizing your therapy.

And yet another ad hominem disparagement - only this time, the author is so anxious to disparage, it has obviously damaged her reading skills. OK then - here we go:

>>Since this thread is really about "oh how terrible those money grubbing companies are" - or possibly about "oh how useless a machine's AHI data" and not about understanding the true differences between machines<<

BS. Pure and unadulterated BS. My questions were sincere - the data reported accurate - and my mind open. That you interpret this topic as you describe speaks FAR more about YOUR lack of an open mind, than it does about the sincerity of the questions and the genuine interest I have in understanding the issues raised. But then again - in your earlier ad hominen disparagement, you had assigned my motive for raising this topic as one of wanting to be "superior" - or some such nonsense. (earlier response found here -- viewtopic.php?f=1&t=56345&st=0&sk=t&sd= ... 45#p529267)

>>Which pressure was chosen for the reported comparison<<

You must have missed this part of my message; "Both machines were configured to be straight CPAP supplying 9cmH2O with a 10 minute ramp that starts at 4cmH2O." (found here -- viewtopic.php?f=1&t=56345&st=0&sk=t&sd= ... 60#p530302)

>>Note the original AHI discrepancy
And compare the AHI difference reported, at an unknown fixed pressure<<

There was nothing unknown about it. It was, as stated upthread - 9cmH2O.

>>so how was the comparison pressure decided upon?<<

jdm2857 made this suggestion; "Maybe you should try straight CPAP (at your typical 90- or 95-centile pressure) on both machines to factor out the effects of the auto algorithm. You'll get a much better picture of the machines' event detection abilities." (found here -- viewtopic.php?f=1&t=56345&st=0&sk=t&sd=a#p528334).

Considering jdm2857' suggestion (yours ozij, was notably absent), I chose a fixed pressure of 9.0cmH2O.

Would you have suggested something different? If so - why did you NOT make the suggestion? I requested, numerous times, for suggestions as to how to proceed. What were yours?

>>We are never shown comparative charts of what the sofware reports for the same time period. Another indication of what this thread is really about.<<

All you needed to do was ask. Apparently (and again) you missed my comment; "Is there any other data from ResScan and/or SmartLink that might be helpful? I can post some graphs if you can point me to the ones that should be posted." (found here -- viewtopic.php?f=1&t=56345&st=0&sk=t&sd=a#p528333) Notably, this comment was from the very same post containing the table of reported pressures you quoted. Is it that you 'missed' it intentionally ozij?

Once again - what graphs would you like to see?

>>Information about the manometer used as a standard for calibrating the machines' pressure before running this comparison. Wouldn't you expect a person who repeatedly points out the importance of standards to make sure he uses one when running his own "experiment". And don't tell me a data inclined sceptic of AHI has suddenly become a believer of reported pressure.<<

True enough - I did not spend the money to purchase a manometer. Both machines are new - purchased within the past 3 months. I will take it on faith that DeVilbiss and ResMed have sufficient quality control that their machines are within 'spec.'

Let me ask you though - based on the data presented, do you have any suspicion that one (or both) of the machines suffer a calibration problem?

>>Information about the level of pressure relief (Flex, EPR)used on either machine for the comparison; unlike the older DeVilbiss firmware, the newer one has a Flex option.<<

As before, all you needed to do was ask. Reference again to my comment - now with emphasis added (maybe it will help your reading); "Is there any other data from ResScan and/or SmartLink that might be helpful? I can post some graphs if you can point me to the ones that should be posted." (found here -- viewtopic.php?f=1&t=56345&st=0&sk=t&sd=a#p528333)

Both the DeVilbiss and the ResMed are using DEFAULT parameters for EPR and SmartFlex. Those are an EPR value of 2 for the ResMed - and an IRnd setting of 3 and ERnd setting of 3 for the DeVilbiss. All settings are at the midpoint within the range of available settings.

>>Information about the settings used on the DeVilbiss to define events - these can be changed by the user.<<

And one more time - just to be sure you see it this time (and assuming reading for comprehension is within your grasp) - "Is there any other data from ResScan and/or SmartLink that might be helpful? I can post some graphs if you can point me to the ones that should be posted." (found here -- viewtopic.php?f=1&t=56345&st=0&sk=t&sd=a#p528333)

Further, I addressed the question of DeVilbiss settings many times in the topic. Had I changed the defaults, I would have specified that. I mentioned the possibility of changing them - but have not.

>>(Yes, I realise some people can't use the way they feel. And I realise that for some of us life can very very tough, furstrating and disappointing).<<

Your mocking innuendo is noted ozij.

Do you feel that is in any way making a constructive contribution to this topic?

Are you capable of making a contribution to THIS topic? Others have told me privately how "loving" you are - and others here in this forum surely have been the beneficiaries of your more gentle nature. You are none of that in this topic. You have been dismissive, intemperate, accusatory, and now mocking. If you have nothing of positive value to contribute - what is YOUR purpose here?

I remain interested in understanding the disparity in the reported metrics from two different manufacturer's devices. There is nothing more. The fact of the disparity naturally raises questions. In seeking answers to those questions, and in the absence of anything definitive, some amount of speculation is likely.

What is it ozij, exactly, that has touched a nerve with you? Is it the speculations? Is it the lack of scientific rigor in presenting my data? What? I am genuinely curious.

[cwied]

True enough - I did not spend the money to purchase a manometer. Both machines are new - purchased within the past 3 months. I will take it on faith that DeVilbiss and ResMed have sufficient quality control that their machines are within 'spec.'

I don't know what 'spec' is here. It may not be as precise as you think. Do you have any references on how accurate the output pressure is supposed to be? If its +/- .5 cm H20 you could have as much as a 1cm difference here.

More importantly:

Both the DeVilbiss and the ResMed are using DEFAULT parameters for EPR and SmartFlex. Those are an EPR value of 2 for the ResMed - and an IRnd setting of 3 and ERnd setting of 3 for the DeVilbiss. All settings are at the midpoint within the range of available settings.

This seems to be a significant variable. I've seen references that imply that EPR can impact therapy efficacy. Not only that, but other quotes lead me to believe that there is a significant proprietary algorithmic variance in determining the switch from inspiration to expiration. I think that this is another variable that should be eliminated if you want to compare the scoring algorithms.

[DHC]

True enough - I did not spend the money to purchase a manometer. Both machines are new - purchased within the past 3 months. I will take it on faith that DeVilbiss and ResMed have sufficient quality control that their machines are within 'spec.'

I don't know what 'spec' is here. It may not be as precise as you think. Do you have any references on how accurate the output pressure is supposed to be? If its +/- .5 cm H20 you could have as much as a 1cm difference here.

More importantly:

Both the DeVilbiss and the ResMed are using DEFAULT parameters for EPR and SmartFlex. Those are an EPR value of 2 for the ResMed - and an IRnd setting of 3 and ERnd setting of 3 for the DeVilbiss. All settings are at the midpoint within the range of available settings.

This seems to be a significant variable. I've seen references that imply that EPR can impact therapy efficacy. Not only that, but other quotes lead me to believe that there is a significant proprietary algorithmic variance in determining the switch from inspiration to expiration. I think that this is another variable that should be eliminated if you want to compare the scoring algorithms.

Thanks for the suggestions, I am happy to try other settings to see if they affect the outputs.

I'll next eliminate EPR and SmartFlex from the equation and record the results.

>>I don't know what 'spec' is here. It may not be as precise as you think. Do you have any references on how accurate the output pressure is supposed to be? If its +/- .5 cm H20 you could have as much as a 1cm difference here.<<

Fair enough. I really was not intending to claim any precision - only that the machines are new and therefore likely to be within spec - whatever that spec may be. Looks like you were pretty accurate with your suggested tolerances. From the ResMed S9 Clinician's Manual - "Pressure Measurement Tolerance is +/- 0.5 cmH2O +/- 4 % of the measured reading." And from the DeVilbiss DV54 User Guide - "Pressure Accuracy +/- 1.0 cmH2O."

So you are correct - even within specification, if one machine were at max tolerance on the high side and the other is at max tolerance on the low side, that could account for a 1.5 cmH2O difference in the reported metrics.

In terms of the manometer - I am not going to that expense. What I *will* do is - sometime in the next couple of weeks I plan to meet with a new sleep doc. When I do, I will ask if they will allow me to use their manometer to insure both devices are outputting correctly.

Thanks again.

[ozij]

>>Which pressure was chosen for the reported comparison<<

You must have missed this part of my message; "Both machines were configured to be straight CPAP supplying 9cmH2O with a 10 minute ramp that starts at 4cmH2O." (found here -- viewtopic.php?f=1&t=56345&st=0&sk=t&sd=a&start=60#p530302)

Yes, I did miss that, I apologize.

That means your AHI on the DeVilbiss is not affected by higher pressure. Which I find very intriguing -- I would certainly expect your AHI to drop with higher pressure.

Which brings up some points worth checking:

• When do the apneas occur? And what do you see on the ResMed chart during that time?
• Do you know the DeVilbiss approach counting apneas during ramp? (And how many times a night did you use ramp (thas is, turn the machine on and off during the night) if at all).

I know ResMed considers ramp time "settling time" and does not use data about events that happend during ramp. If I remember correctly -- and I may be wrong about that -- Devilbiss does count the events in ramp in the reported AHI - but then, I trialed an older version of the firmware in any case. You should find that info in your manual.

As before, all you needed to do was ask. Reference again to my comment - now with emphasis added (maybe it will help your reading); "Is there any other data from ResScan and/or SmartLink that might be helpful? I can post some graphs if you can point me to the ones that should be posted." (found here -- viewtopic.php?f=1&t=56345&st=0&sk=t&sd=a#p528333)

I think that is up to you to figure out. At this point, (see above) I would like to see the ramp time in both charts, and the Resmed charts for those times when DeVilbiss reported apneas.

I am also wondering what the result would be when you run both machines at the DeVilbiss' 95% pressure. (By the way, is it really 95% and not 90%? My PB 420E let me change the cutoff point, I know Respironics is hard coded at 90% and ResMed at 95% -- I don't remember DeVilbiss').

True enough - I did not spend the money to purchase a manometer. Both machines are new - purchased within the past 3 months. I will take it on faith that DeVilbiss and ResMed have sufficient quality control that their machines are within 'spec.'

I don't know what 'spec' is here. It may not be as precise as you think. Do you have any references on how accurate the output pressure is supposed to be? If its +/- .5 cm H20 you could have as much as a 1cm difference here.

More importantly:

Both the DeVilbiss and the ResMed are using DEFAULT parameters for EPR and SmartFlex. Those are an EPR value of 2 for the ResMed - and an IRnd setting of 3 and ERnd setting of 3 for the DeVilbiss. All settings are at the midpoint within the range of available settings.

This seems to be a significant variable. I've seen references that imply that EPR can impact therapy efficacy. Not only that, but other quotes lead me to believe that there is a significant proprietary algorithmic variance in determining the switch from inspiration to expiration. I think that this is another variable that should be eliminated if you want to compare the scoring algorithms.

I agree with both points.

>>(Yes, I realise some people can't use the way they feel. And I realise that for some of us life can very very tough, furstrating and disappointing).<<

Your mocking innuendo is noted ozij.

I am not mocking anyone or anything in this sentence, I am stating a sad fact of life - life can be very cruel to some people - I was thinkigy of LoQ, for instance, who mentioned in another thread that she had enough other medical conditions to make it impossilble for her to gauge cpap progress by the way she feels - I think that is very tough. However, that is the exception, and I stand by my statement of the rule that the "the machine you should choose is the machine that makes you feel better".

[jnk]

. . . In terms of the manometer - I am not going to that expense. What I *will* do is - sometime in the next couple of weeks I plan to meet with a new sleep doc. When I do, I will ask if they will allow me to use their manometer to insure both devices are outputting correctly . . .

Sounds reasonable. But I will take the opportunity to put in a shameless plug for the hosts, anyway:

https://www.cpap.com/cpap-machine/fishe ... amber.html

[jonquiljo]

Sounds reasonable. But I will take the opportunity to put in a shameless plug for the hosts, anyway:

https://www.cpap.com/cpap-machine/fishe ... amber.html

That's not shameless at all. I certainly would like one ..... Thanks.

[DHC]

>>Which pressure was chosen for the reported comparison<<

You must have missed this part of my message; "Both machines were configured to be straight CPAP supplying 9cmH2O with a 10 minute ramp that starts at 4cmH2O." (found here -- viewtopic.php?f=1&t=56345&st=0&sk=t&sd=a&start=60#p530302)

Yes, I did miss that, I apologize.

That means your AHI on the DeVilbiss is not affected by higher pressure. Which I find very intriguing -- I would certainly expect your AHI to drop with higher pressure.

Which brings up some points worth checking:

• When do the apneas occur? And what do you see on the ResMed chart during that time?
• Do you know the DeVilbiss approach counting apneas during ramp? (And how many times a night did you use ramp (thas is, turn the machine on and off during the night) if at all).

I know ResMed considers ramp time "settling time" and does not use data about events that happend during ramp. If I remember correctly -- and I may be wrong about that -- Devilbiss does count the events in ramp in the reported AHI - but then, I trialed an older version of the firmware in any case. You should find that info in your manual.

As before, all you needed to do was ask. Reference again to my comment - now with emphasis added (maybe it will help your reading); "Is there any other data from ResScan and/or SmartLink that might be helpful? I can post some graphs if you can point me to the ones that should be posted." (found here -- viewtopic.php?f=1&t=56345&st=0&sk=t&sd=a#p528333)

I think that is up to you to figure out. At this point, (see above) I would like to see the ramp time in both charts, and the Resmed charts for those times when DeVilbiss reported apneas.

I am also wondering what the result would be when you run both machines at the DeVilbiss' 95% pressure. (By the way, is it really 95% and not 90%? My PB 420E let me change the cutoff point, I know Respironics is hard coded at 90% and ResMed at 95% -- I don't remember DeVilbiss').

True enough - I did not spend the money to purchase a manometer. Both machines are new - purchased within the past 3 months. I will take it on faith that DeVilbiss and ResMed have sufficient quality control that their machines are within 'spec.'

I don't know what 'spec' is here. It may not be as precise as you think. Do you have any references on how accurate the output pressure is supposed to be? If its +/- .5 cm H20 you could have as much as a 1cm difference here.

More importantly:

Both the DeVilbiss and the ResMed are using DEFAULT parameters for EPR and SmartFlex. Those are an EPR value of 2 for the ResMed - and an IRnd setting of 3 and ERnd setting of 3 for the DeVilbiss. All settings are at the midpoint within the range of available settings.

This seems to be a significant variable. I've seen references that imply that EPR can impact therapy efficacy. Not only that, but other quotes lead me to believe that there is a significant proprietary algorithmic variance in determining the switch from inspiration to expiration. I think that this is another variable that should be eliminated if you want to compare the scoring algorithms.

I agree with both points.

>>(Yes, I realise some people can't use the way they feel. And I realise that for some of us life can very very tough, furstrating and disappointing).<<

Your mocking innuendo is noted ozij.

I am not mocking anyone or anything in this sentence, I am stating a sad fact of life - life can be very cruel to some people - I was thinkigy of LoQ, for instance, who mentioned in another thread that she had enough other medical conditions to make it impossilble for her to gauge cpap progress by the way she feels - I think that is very tough. However, that is the exception, and I stand by my statement of the rule that the "the machine you should choose is the machine that makes you feel better".

>>Yes, I did miss that, I apologize.<<

Apology accepted. Thank you.

>>That means your AHI on the DeVilbiss is not affected by higher pressure. Which I find very intriguing -- I would certainly expect your AHI to drop with higher pressure.<<

I agree, it is curious.

>>When do the apneas occur? And what do you see on the ResMed chart during that time?<<

Here are some charts from the IntelliPAP:

First are the charts from setting a range from 6.0 cmH2O to 10.0 cmH2O:

October 07/08:
and


October 08/09:
and


Then to those graphs when using straight CPAP at 9.0 cm H2O:

October 15/16:


October 16/17:


And some from the S9:

Starting with those while on a range of pressures - the same range as above - 6.0 cmH2O to 10.0 cmH20"

October 09/10:
and


October 10/11:
and


And then after changing to a fixed pressure of 9.0 cmH2O:

October 14/15:
and


October 17/18:
and


This represents a sampling of the available graphs - not all of the graphs available for any single night, and not for all nights. If there are other metrics or other nights that might be helpful for me to post, just let me know.

>>Do you know the DeVilbiss approach counting apneas during ramp? (And how many times a night did you use ramp (thas is, turn the machine on and off during the night) if at all).<<

I can see that it has not recorded any events during the ramp ("delay" in DeVilbiss vernacular). Same for the S9 - no events recorded during the ramp-up.

The ramp/delay setting has been used for ALL nights. It is set for 10 minutes starting at 4 cmH2O. In terms of interruptions during the night (that might reset the ramp-up), there have been none, and the IntelliPAP is set to not use a "Split Night Delay."

>>I am also wondering what the result would be when you run both machines at the DeVilbiss' 95% pressure. (By the way, is it really 95% and not 90%? My PB 420E let me change the cutoff point, I know Respironics is hard coded at 90% and ResMed at 95% -- I don't remember DeVilbiss').<<

Yes, I was careful to select the 95th Percentile Pressure from the DeVilbiss reports. They list the 95th Percentile, the 90th Percentile, the Average, Median, and Max. The ResMed reports indicate Median, 95th Percentile, and Maximum - so I picked the 95th Percentile figures from each of the IntelliPAP and S9 reports as a direct comparison.

My interpretation of an approximate mean of the 95th Percentile for the IntelliPAP only would be 7.0 cmH2O. Would you agree? If so, I will use that value for a few nights and record the results.

Re: EPR and SmartFlex. I plan to turn off both those features and see if it produces any change in the results. Will probably wait till AFTER the change to the fixed pressure of 7.0 as I would like to know which settings are responsible for any changes in the reported metrics.

Re: Specification Tolerances. I hope to be allowed to use a manometer soon to confirm the reported pressures for both machines. Will report the results if/when I get them. Otherwise, there seems to be as much as 1.5 cmH2O potential disparity due solely to tolerances.

>>I would like to see the ramp time in both charts, and the Resmed charts for those times when DeVilbiss reported apneas.<<

The charts above contain the ramp/delay information. I am not sure I understand what you mean by "the Resmed charts for those times when DeVilbiss reported apneas." I think you mean to first establish a pattern of events reported by the IntelliPAP - should a pattern exist. Then look at the same proximate timeframes on the S9 charts to see how the S9 responded to the same sorts of events. Is that correct? If so, I confess to not being able to detect a discernible pattern of events in the IntelliPAP reports. Do you see any?

[ozij]

Thank you for providing the additonal info, DHC.

It's clearly not a ramp issue.

My interpretation of an approximate mean of the 95th Percentile for the IntelliPAP only would be 7.0 cmH2O. Would you agree? If so, I will use that value for a few nights and record the results.

I agree. But do it only if you don't feel that pressure is too low for comfort.

I think you mean to first establish a pattern of events reported by the IntelliPAP - should a pattern exist. Then look at the same proximate timeframes on the S9 charts to see how the S9 responded to the same sorts of events. Is that correct? If so, I confess to not being able to detect a discernible pattern of events in the IntelliPAP reports. Do you see any?

Sorry, bad lack of concentration on my part. I am so used to running comparisons of my SPO2 with my ResScan reports that I used that type of comparison thinking for your therapy charts - as though they were concurrent. The machines aren't running concurrently... no wonder you didn't understand me...

I'll respond to the data in more detail tomorrow. Off to bed now.

[john5757]

Looking just the pressure charts and it looks like to me that the ResMed is responding more to events with a pressure change than the IntelliPAP. The charts that are shown here shows the IntelliPAP is barely making any pressure changes while the ResMed is showing much higher pressure changes. I did try the IntelliPAP for a month but I feel at the time that the ResMed and the Sandman gave me better therapy. It strikes me, that 95th Percentile for the IntelliPAP at 7.0 cmH2O would be very low for me and the I would think that the ResMed 95th Percentile would be higher and closer to your needs. Thas is just my opinion after five years on CPAP and four AutoCap that I have tried.
There are other variables like how fa

[john5757]

Looking just the pressure charts and it looks like to me that the ResMed is responding more to events with a pressure change than the IntelliPAP. The charts that are shown here shows the IntelliPAP is barely making any pressure changes while the ResMed is showing much higher pressure changes. I did try the IntelliPAP for a month but I feel at the time that the ResMed and the Sandman gave me better therapy. It strikes me, that 95th Percentile for the IntelliPAP at 7.0 cmH2O would be very low for me and the I would think that the ResMed 95th Percentile would be higher and closer to your needs. Thas is just my opinion after five years on CPAP and four AutoCap that I have tried.
There are other variables like how fast the machine responses to events and how fast it goes down to baseline pressure effects the quality of sleep as well.

[DHC]

Looking just the pressure charts and it looks like to me that the ResMed is responding more to events with a pressure change than the IntelliPAP. The charts that are shown here shows the IntelliPAP is barely making any pressure changes while the ResMed is showing much higher pressure changes. I did try the IntelliPAP for a month but I feel at the time that the ResMed and the Sandman gave me better therapy. It strikes me, that 95th Percentile for the IntelliPAP at 7.0 cmH2O would be very low for me and the I would think that the ResMed 95th Percentile would be higher and closer to your needs. Thas is just my opinion after five years on CPAP and four AutoCap that I have tried.
There are other variables like how fast the machine responses to events and how fast it goes down to baseline pressure effects the quality of sleep as well.

Yes - I believe your comments are directed at the auto features. When using a static fixed pressure, auto responses from the devices are removed from the algorithm.

Soon after I posted those charts, I recognized that I may have set the S9 range differently from the IntelliPAP range. I *thought* had set both ranges to be 6 cmH2O to 10 cmH2O - but it now looks like I had allowed the S9 a higher maximum limit of 12 cmH2O. While it never reached that limit, the fact of the IntelliPAP being set to a max of 10 while the S9 was free to go beyond that, I believe, renders the comparison invalid. I need to re-do those.

Insofar as what appears to be a more aggressive response by the S9, I notice that I am sensitive to fairly small increases in pressure. Likely it is because I try to keep my mask as loose as possible for a comfortable fit while still maintaining a good seal with minimal leaks. A 2 cmH2O increase definitely affects the sealing of the mask, and with leaks comes frequent 'arousals' to fix the mask and I do not sleep well. I seem to recall the DeVilbiss materials stating their algorithm makes no more than 1.0 cmH2O/minute increase in pressure, and no more than 0.1 cmH2O/minute decrease in pressure. I am not aware of the corresponding ResMed rate of change limitations - if any.

Re: The proposed 7.0 cmH2O fixed pressure for comparison. My original sleep study showed an AHI of 39/hour - all hypopneas. With titration at 7.0 cmH2O the AHI dropped to 2/hour - and that was the original CPAP prescription - almost a year ago. Since then I had 3-level ACDF (spine fusion surgery - access through the front of the neck) and it forced me to use the CPAP machine that I was almost entirely non-compliant with prior to the surgery. Since the surgery (July) I have been 100 % compliant. Point being - the sleep study basis is now different - although I *do* seem to do OK at lower pressures - witness the IntelliPAP charts and results previously posted.

Thank you for your comments. I need to do a bit more work to get something even close to a direct comparison of the devices it seems, but I'll keep at it.