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Sleepyhead - adjusting 90% Pressure Calculation
#1
My xPAP doc office (they have changed back and forth between APAP and CPAP modes) only wants/acknowledges a "95%" for the "Pressure" Calculation.

Pretty much they "blew me off" on my complaints about pressure since "your software isn't calculating it right"....

I'm hypoxic (drop from 95% to 85% or so [blood O2]) -- for 20-30 minutes since I'm struggling to breathe at start (yes, Ramp is off) -- When in APAP mode they have it set to 5 to 15. When in CPAP mode they hard-set to 14 and I seem to start off worse, at 4.

The frustrating thing is I can go to bed nearly ready to fall asleep, and almost always I'm wide awake fighting the low pressure -- sucking air, hypoxic, etc.

I can fake snoring, or hold my breath -- if I'm desperate -- and it will adjust up more rapidly. But that screws with my AHI calculations and events.

...and I'm getting blasted/leaking at top end (or on CPAP 14 as currently set) - but my Apnea's aren't signficant prior to the top end (above about 12) - I can't tolerate tightening down the mask to prevent leaks at the "really high blast"... but I don't leak much at all at a slightly lower top-end.

I see where I can adjust using File/Preferences/CPAP - the "Upper Percentile" = 95%

But that doesn't seem to adjust the "Statistics Page" -- still reads "90% Pressure Calculation" and I assume still calculates at 90% -- even if I "rebuild CPAP data"

Otherwise, about 1.5 months into CPAP/APAP --- not really feeling any significant difference -- struggling some days to maintain compliance -- find myself checking my watch when I wake up "how much longer until I'm past 4 hours" -- but it's getting better. Been known to watch TV in the morning with the mask on just to "get a few more minutes in" to make compliance.

Learned ~not~ to turn off my machine if I take off the mask -- otherwise I have to go back to 4 and wait 20-30 minutes again so I can breathe well.

Before CPAP -- AHI 99. With CPAP/APAP -- below 3 on Average.

SleepyHead v1.0.0-beta-2 - cb213cc OpenGL

...Chuck
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#2
What I get out of that is: Sounds like they have you at 14 in CPAP mode with Ramp *ON* -- check it -- it wouldn't start at 4 if ramp were OFF.
And, your *xPAP doc office* needs to go back to school on statistics. The difference between the 90th and 95th percentile pressure is small.
BTW -- what was your 90% pressure when on Auto?

And, what do you mean by:
Quote:but my Apnea's aren't significant prior to the top end (above about 12)
?

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#3
(11-16-2016, 07:49 AM)justMongo Wrote: What I get out of that is: Sounds like they have you at 14 in CPAP mode with Ramp *ON* -- check it -- it wouldn't start at 4 if ramp were OFF.

Darn it. I had it ramp-off for APAP and just ~assumed~ it was off when they changed to CPAP mode -- nope, it was on "auto" -- let's see how tonight goes!!!

I was going to say it seemed to ramp-up only when I fake-snored or actually was able to go to sleep. Guess that's what "auto" does on CPAP.

(11-16-2016, 07:49 AM)justMongo Wrote: And, your *xPAP doc office* needs to go back to school on statistics. The difference between the 90th and 95th percentile pressure is small.
BTW -- what was your 90% pressure when on Auto?

Generally was 14.5 to 15 (APAP was 5-15) -- some nights 13.5 or so.

Upon first followup, just was switched to CPAP at solid 14.

Amen re "go back to class on statistics" -- I tried to discuss it with the "nurse" who did the follow-up appointment after 30 days. She seemed to be just focused on a "Script" to follow -- instead of an intelligent patient (am an Engineer) who brought graphs, etc to show what was going on. Was dismissed and brought out the Resmed "in the sky" report which has no detail on it, just a 95% calculation.

(11-16-2016, 07:49 AM)justMongo Wrote: And, what do you mean by:
Quote:but my Apnea's aren't significant prior to the top end (above about 12)
?

I mean, I have little apneas once it cranks up to about 10 or higher. And at 12 still few -- so having it continue to go up to 14 or beyond doesn't seem to linearly change anything significantly -- as I was told, below 5 AHI was the goal.

What I am trying to say is "Blasting me at 14" or more isn't really making the AHI significantly less -- and I'm already below 5.

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#4
Another part of the problem may be that SleepyHead had the 90% hard coded in the label, regardless of the value used in the calculation - at least in version 0.9.8. I had worked on a patch for that and now can't recall if I submitted it, let alone had it accepted. (It was a bit fussy...) I _think_ the desired percentile is used for the calculation and the label is unchanged, but I haven't checked recently. My life has been a bit chaotic the last few months.
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#5
The SleepyHead calculation statistics can be configuredj in File/Preferences/CPAP. The Calculaton preferences can show any desired upper percentile, and the middle calculations can be set to Median or Average. The Maximum calculations are 100% by default, but I have mine set to 99% to get a more meaningful number.

The dismissive attitude by your doctor is pretty insulting. Once you have been at this for a while, you will know best what is comfortable and works well for you. It's a blend of data and how you feel, and only you can know. Ramp is fine for starting out, but the default ramp starting at 4 cm and lasting 45 minutes is crazy. I don't use it, and sounds like that is your preference as well. When a machine has run "wide-open" for a while, I usually advise people to set the minimum APAP pressure equal to the average pressure. That usually feels pretty comfortable, and is high enough for the machine to increase pressure to stop obstructive events when they occur. CPAP pressure does work better for some, and for others, it is just a lot of unnecessary pressure. It is set high enough to stop obstructive events in worst case sleep stage and body position, so most of us don't need that all the time.

One last thing. Your machine has EPR (exhale pressure relief) of up to -3 cm during exhale. It is like bilevel. Having a different inhale and exhale pressure (IPAP/EPAP) improves ventilation volume in most people. If you are not using it, give it a try.
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#6
I will add a comment that an AHI of < 5 is considered treated (sometimes referred to as normal). However, that might not leave you feeling the greatest. I can really feel the effect the next day of anything over a 2. Everyone is different. So if you are still not feeling it, that may be part of an explanation.
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#7
I have the ramp activated only 5 minutes, almost always at that time the dream takes over me, because of that the initial snoring that I had disappeared, thanks to your advice to raise the minimum to 8 cmh2o
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