EPR: just a comfort feature or affects AHI

-SWS · Post by **-SWS** » Thu Mar 31, 2011 8:25 pm

billbolton wrote: So, the answer to my question is?

Exactly 12 posts ago:

NotMuffy wrote: these apnea times were calculated by ResScan and identified as CAs.

robysue wrote:those graphs for both the Patient Flow and the Mask Pressure that are clearly NOT being generated by ResScan?

http://www.google.com/search?q=EDFbrows ... =firefox-a

FigeFaislange wrote: thanks

welcome!

-SWS · Post by **-SWS** » Thu Mar 31, 2011 9:14 pm

NotMuffy wrote:
-SWS wrote:Looking at NotMuffy's patient flow graph above:
-Exhalation ends a little after t=7 seconds
-FOT pulsation or "FOT scout" begins in the flow signal a little after t=11 seconds (4 seconds after exhalation according to Resmed spec)
-FOT pulsation continues right up until around t=29 seconds---which is the very peak of that first inhalation immediately after the above apnea

Now looking at NotMuffy's mask pressure graph above:
-EPR is in effect when the apnea begins
-EPR stays in effect the duration of the apnea
-Therefore EPR does not suspend in the middle of a detected apnea
BTW, these apnea times were calculated by ResScan and identified as CAs.

It seems as though EPR _________ suspended during FOT.

Now we need to "fill in the blank". "IMHO", I don't believe FOT can be suspended without sending in a flow profile that will inevitably make any event identified as a central. Thus, it "can't be" suspended.

Thanks again for the above graph and analysis, NotMuffy.

Above we can see that EPR is not suspended during the central apnea. I think it's technically possible to suspend EPR during FOT and not create a central-apnea false positive: apply context-sensitive "notch filtering" to eliminate the FOT frequency. But I don't think Resmed has a compelling design reason to do that. Little would be accomplished for the apnea that is already "water over the dam" so to speak. And if the event is a central apnea, the slow static pressure increase could actually worsen the central dysregulation.

...And what does jnk think at this point? He's been calling 'em well IMO. So what think ye, Mr. Jeff?

-SWS · Post by **-SWS** » Thu Mar 31, 2011 9:23 pm

BernieRay wrote:From last night (APAP 10-13, EPR=3):

18 second central:

11 second obstructive:

Based on this, it certainly appears to confirm that EPR is continuous throughout FOT and FOT appears to operate near the min allowed pressure including EPR (10-3=7). It also looks like ResScan displays the pressure graph based on therapy pressure from the PLD file instead of mask pressure from the BRP file, explaining why EPR doesn't show in ResScan. Are those conclusions correct, or did I miss something?

Great and thanks, BernieRay...

Just to comment that the EPR pressure drop occurs at the mask despite any contrary pressure data in the files... The premise of EPR is to provide that comfortable pressure drop beyond the mask and all the way into the airway.

jnk · Post by **jnk** » Thu Mar 31, 2011 9:33 pm

-SWS wrote:...And what does jnk think at this point? He's been calling 'em well IMO. So what think ye, Mr. Jeff?

I'm still trying to soak it all in. I learn a lot from these discussions, but it takes me a while to process it in my head. I do know what I feel, though, which is gratitude that I found this board where these discussions can occur in this way, for the lay patient like me. Thank you very much, my friend, for what you discuss here and how you discuss it.

I have mixed feelings about ResMed. I like their machines. I like the approach of the S8 II AutoSet enough to make it my next machine if they are still around when I'm in the market. But I am still curious about the S9. And hearing you and Dave and ozij talk about the claims and the results and the implications helps me weigh it.

Funny thing is, given the nature of my OSA, it probably doesn't amount to a hill of beans what machine I use--I could probably get decent enough therapy on any of them of any brand, since I am not having any problems with my therapy and even felt I did well enough on that M series I tried, for that matter.

FOT would not likely give me, personally, much useful information. But I do very much like the idea of suspending EPR, and my autobilevel doesn't do that, obviously. Maybe it was silly of me to push for bilevel like I did at my titration, since if I had not, I might have ended up with an S8 AutoSet.

How is it going for you with your S9, and in general, if you don't mind my asking?

-SWS · Post by **-SWS** » Thu Mar 31, 2011 9:38 pm

jnk wrote:How is it going for you with your S9, and in general, if you don't mind my asking?

I think my basic SDB is easy to treat. So on that basis SDB treatment is going very well for me with S9. The EPR works very well for me and the ultra-low noise generated by that machine is a treat compared to my older-generation machines. Despite the excellent SDB treatment I receive, my sleep is fairly deteriorated thanks to chronic pain. I can't blame that on S9.

jnk · Post by **jnk** » Thu Mar 31, 2011 9:47 pm

-SWS wrote:
jnk wrote:How is it going for you with your S9, and in general, if you don't mind my asking?
I think my basic SDB is easy to treat. So on that basis SDB treatment is going very well for me with S9. The EPR works very well for me and the ultra-low noise generated by that machine is a treat compared to my older-generation machines. Despite the excellent SDB treatment I receive, my sleep is fairly deteriorated thanks to chronic pain. I can't blame that on S9.

My heart goes out to you on the pain.

Has mask choice made any difference, all in all?

Your posts through the years have surely alleviated a lot of other people's difficulties. I wish there was more that could be done to help yours.

ozij · Post by **ozij** » Thu Mar 31, 2011 9:54 pm

Otter wrote:
ozij wrote:When it showed S8 data, ResScan used to show 2 pressure lines, the bottom line was for average pressure which included EPR -- and I could see it rise towards the upper "therapy" (i.e. inhale) pressure after events. For some reason, they stopped that presentaton in the S9.
Was it with the S9 or with one of the Rescan revisions?
It's the machine, not the ResScan version.

And is the S9 still logging the data so that we can see it when Jedimark's software is ready?

I don't know....

BernieRay · Post by **BernieRay** » Fri Apr 01, 2011 3:46 am

Robysue, I used EDFBrowser, like someone earlier provide a link for.

ozij wrote:
Otter wrote:
ozij wrote:When it showed S8 data, ResScan used to show 2 pressure lines, the bottom line was for average pressure which included EPR -- and I could see it rise towards the upper "therapy" (i.e. inhale) pressure after events. For some reason, they stopped that presentaton in the S9.
Was it with the S9 or with one of the Rescan revisions?
It's the machine, not the ResScan version.

And is the S9 still logging the data so that we can see it when Jedimark's software is ready?
I don't know....

I'm fairly certain it is. There's at least 3, if not 4, pressures being logged in the EDF files.I want to say I remember seeing both lines with either 3.11 or 3.12, but I'm not certain.

NotMuffy · Post by **NotMuffy** » Fri Apr 01, 2011 5:59 am

BernieRay wrote:Robysue, I used EDFBrowser, like someone earlier provide a link for.

ozij wrote:
Otter wrote:
ozij wrote:When it showed S8 data, ResScan used to show 2 pressure lines, the bottom line was for average pressure which included EPR -- and I could see it rise towards the upper "therapy" (i.e. inhale) pressure after events. For some reason, they stopped that presentaton in the S9.
Was it with the S9 or with one of the Rescan revisions?
It's the machine, not the ResScan version.

And is the S9 still logging the data so that we can see it when Jedimark's software is ready?
I don't know....
I'm fairly certain it is. There's at least 3, if not 4, pressures being logged in the EDF files.I want to say I remember seeing both lines with either 3.11 or 3.12, but I'm not certain.

I think you're right. It's probably "Exp Press", and represents "Therapy Pres" minus current EPR. Also, given the frequency of the signal update, it looks like a machine (calcuated) value rather than a measured one.

BernieRay · Post by **BernieRay** » Fri Apr 01, 2011 7:30 am

NotMuffy wrote:
BernieRay wrote:Robysue, I used EDFBrowser, like someone earlier provide a link for.

ozij wrote:
Otter wrote:
ozij wrote:When it showed S8 data, ResScan used to show 2 pressure lines, the bottom line was for average pressure which included EPR -- and I could see it rise towards the upper "therapy" (i.e. inhale) pressure after events. For some reason, they stopped that presentaton in the S9.
Was it with the S9 or with one of the Rescan revisions?
It's the machine, not the ResScan version.

And is the S9 still logging the data so that we can see it when Jedimark's software is ready?
I don't know....
I'm fairly certain it is. There's at least 3, if not 4, pressures being logged in the EDF files.I want to say I remember seeing both lines with either 3.11 or 3.12, but I'm not certain.
I think you're right. It's probably "Exp Press", and represents "Therapy Pres" minus current EPR. Also, given the frequency of the signal update, it looks like a machine (calcuated) value rather than a measured one.

Either that, or it's the mask pressure from the PLD file. I'll post some new EDFBrowsers charts showing all pressures from both the BRP and PLD file, as well as flow and events when I get home. I've already got them created, but I can't host them at the moment.

-SWS · Post by **-SWS** » Fri Apr 01, 2011 8:27 am

jnk wrote: Has mask choice made any difference, all in all?

I think masks with smaller trigeminal contact area are probably less aggravating. So the last few months I have been using an Activa LT nasal mask instead of my usual FFM. But so far I can't sleep with Nasal Air unfortunately. Thanks for suggesting!

BernieRay wrote: I'll post some new EDFBrowsers charts showing all pressures from both the BRP and PLD file, as well as flow and events when I get home. I've already got them created, but I can't host them at the moment.

Thanks in advance! That EDFbrowser looks sure looks useful, and the $0.00 price is right... I think I'll give it a try this weekend.

BernieRay · Post by **BernieRay** » Fri Apr 01, 2011 8:44 am

-SWS wrote:
BernieRay wrote: I'll post some new EDFBrowsers charts showing all pressures from both the BRP and PLD file, as well as flow and events when I get home. I've already got them created, but I can't host them at the moment.
Thanks in advance! That EDFbrowser looks sure looks useful, and the $0.00 price is right... I think I'll give it a try this weekend.

It definitely is a nice companion tool for ResScan. Using it, if you aren't familiar with such tools, isn't straightforward, but it didn't take me too much time to figure things out. If I get time, I may post some simple instructions on how I created these charts. No promises, but I'll try.

BernieRay · Post by **BernieRay** » Fri Apr 01, 2011 3:57 pm

Here are the new graphs. The top 2 traces come from the BRP file. The other 3 are from the PLD file. Event annotations came from the EVE file after I used EDFBrowser to convert a copy of it to a continuous format.

18s central:

11s obstructive:

Otter · Post by **Otter** » Fri Apr 01, 2011 7:30 pm

Thanks. What was the EPR setting that night?

BernieRay · Post by **BernieRay** » Fri Apr 01, 2011 7:34 pm

BernieRay wrote:From last night (APAP 10-13, EPR=3):

EPR: just a comfort feature or affects AHI

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