EPR: just a comfort feature or affects AHI

Thanks, RG!

billbolton wrote:

-SWS wrote: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

The question of how would the machine know that an apnea (as distinct from something else, possibly undefined) was in progress, purely from data that can be determined from the air circuit, would appear to be germane here?

If the machine was unable to definitely score an apnea, then it would have no cause to cease EPR.

Did the machine formally score an event, and if so what class of event did it score it as?

Cheers,

Bill

The patient flow is approximately 0 lps from t=7 seconds until that little bump right around t=24 seconds. Zero flow for that many consecutive seconds is an apnea by Resmed's definition. But we need to subtract FOT squiggles---which are not patient flow. Then there's a little patient flow registered at around t=24 seconds---and that flow magnitude is still low enough and short enough that the apnea is sustained by definition until that first tall inhalation hump.

Thank you, RG. My apologies for not having been clearer: it was sleepydave's image on apneasupport.org that I couldn't get. The above is on photobucket, and I did see it.

I've found a solution to bypass imageshack's nonsense -- but I prefer a boycott...

O.

ahhh. ok. I should have paid more attention to the difference between the words "imageshack" and "photobucket."

-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.

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?

I can't see your images, Bernie. I don't live in the State, and imageshack is discriminating between US users and others.

They're on PhotoBucket now, ozij. Thanks for letting me know.

And I can see them . Thank you.

"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 ERF doesn't show in ResScan. Are those conclusions correct, or did I miss something?"

I take it you mean EPR and not ERF there? Or what is ERF?

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.

Central (open airway) apneas indicate "no need to raise the pressure" - if your pressure changes after them, that's due to flow limitations -- those jagged breaths.

Yeah, that was a typo I corrected to EPR whilst you were posting. You'd think I could type after a good night of rest.

I started CPAP about 3 months ago and i had the EPR setting set at 2. I set it at 3 last night and my AHI report was .03. Since i started i was always at 0.0 or sometimes 0.1 (pressure=6). Going back to a setting of 2 from now on....

thanks

jfm741 wrote:I started CPAP about 3 months ago and i had the EPR setting set at 2. I set it at 3 last night and my AHI report was .03. Since i started i was always at 0.0 or sometimes 0.1 (pressure=6). Going back to a setting of 2 from now on....

While I would never suggest not trying to lower AHI, I wouldn't be worried about any differences below 1. (I stay below that, but I wouldn't too be concerned until it got to 5.0.) If it were me, I'd simply find which EPR setting I felt better with and not worry about a 0.2-0.3 difference. I used a non-data capable CPAP for 13+ years and did just fine.

Just my 2 cents...

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

Basic curiosity question here for BernieRay:

How are you creating those graphs for both the Patient Flow and the Mask Pressure that are clearly NOT being generated by ResScan?

-SWS wrote:The patient flow is approximately 0 lps from t=7 seconds until that little bump right around t=24 seconds....

The question is what did the machine, a rule-drive computer, score (and by implication, report) the event as, not what you, a human observer, scored the event as

So, the answer to my question is?

Cheers,

Bill