better one? or better two?oscar chart comparisons

[zonker]

i'm composing this offline in hope that i can spell check it and make sure i'm crafting sentences that will make sense to all. this is a daunting task, but want to make sure i get the point across.

this is likely to be a long post. so for those of you with less patience for nattering, i'll give you the shorter version. i'm going to post two sets of oscar charts. one will be three taken from my philips machine and the other from my resmed. they are a bit different and i just wanted to show you all. now on with the long boring blah-blah-blah.

on jan 4th this year, i decided to send my resmed airsense 10 autoset for her to acbio for repair. it had been making a strange sound, sort of like a mooing or moaning sound when operating. i also thought that it wasn't quite doing it's job as over a period of many months, no matter how much i increase my pressure, ahi stayed relatively the same. i finally got to the point where i had basically turned it into a regular straight pressure cpap, with the min pressure at 20 and the max pressure at 20. and the ahi STILL remained the same.

fortunately, like all smart cpaptalk.com forum members, i have a backup machine. so while this was away, i had the opportunity to use my old philips remstar auto system one. i had put this one aside a few years ago. it had stopped doing auto on/auto off. and i'd read SO much about the "for her". plus, i happened to have some spare cash. so i put all these excuses together and bought it, regulating the philips to backup duty.

i set it up to have a min of 18 and a max of 20. this is what i had settled back to with the resmed after the experimenting of higher pressure. i also set it up so that it didn't have flex, same as the "for her" not having epr turned on. it took a couple of nights to get used to it. the algorithm was just different enough that i had to get my breathing rhythm in sync with the machine. but that was minor and soon in hand.

what i found even after the first night of using the system one is my low ahi. except for on outlier night of 0.67, the entire month of january saw ahi's of 0 to .22! i haven't felt this good in a very long time. the resmed had me near this level winter of 2019 into spring of 2020. that tapered off and ahi's climbed from spring until i decided to send it in for repair.

so i finally got my resmed back from acbio feb 4th and plug it in to give it a go that night, cuz i'm anxious to see how my newly fixed machine would go!

it was a disappointment. again, with everything on the machine set as before, i got an ahi of .78, 7.6 and .45. this is comparable to the ahi i was getting before i sent the furshlugginer thing away for repair!

i think it interesting that the remed also shows the bulk of ahi made up of hypopneas, same as philips. but many more hypopneas in the resmed.

take a look first at the philips data for feb 1, 2 and 3-

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[zonker]

and here is the resmed data for feb 4, 5, and 6-

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is it possible that i slept differently those nights? yeah, anything is possible, i suppose. but i'm a bit skeptical when i see just how quickly and consistently my ahi plummeted on the philips and how quickly it shot up on the resmed.

do i feel any different on either machine? am i suddenly all WOW! on the philips and so horrible on the resmed? not really. but i think psychologically i feel better on a machine that shows me with a regular low ahi, that's for sure.

i've made up my mind that the philips is now my main machine and the resmed is regulated to backup status. i'm just posting this in case anyone cares to comment.

[Dog Slobber]

but i think psychologically i feel better on a machine that shows me with a regular low ahi, that's for sure.

This is the most important statement in the two posts.

And with the two sets of numbers both under 1, sleeping better because of a greater comfort level should be a priority.

Having said that, I believe the difference between the ResMed and the Respironics machines isn't necessarily that you are experiencing *more* hypopneas on the ResMed. Instead the difference between the two devices is the accuracy of them to detect an Hypopnea.

You are giving them both the same ability and accuracy to detect events. And that may not be true.

This study is a little old, from the RemStar/S8 days, but it compares CPAP devices ability to accurately detect events.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3767059/

When comparing ResMed and Respironics algorithms, almost always ResMed are considered to be more responsive. One explanation for their responsiveness is in their event accuracy. Respironics won't respond to triggers that they can't measure.

You're pushing 18-20 centimetres of pressure, there is nothing different about Respironics pressure compared to ResMeds pressure, whereby it will prevent your from experiencing hypopneas. 18cm is 18cm.

So the difference between the two is likely a difference in ability to detect apneas.

Now which one is *more* accurate.

What do you prefer?
To be experiencing hypopneas that are not being detected and reading 0.0 in the morning.
or
To be measuring hyopneas that may (or may not) be there and reading 0.45 in the morning.

[Miss Emerita]

DS has a really interesting and informative perspective on this! A few other thoughts.

Given that we can see a flow limitation graph for the ResMed machine, and that it's pretty active, have you considered setting your minimum to 19 and using EPR of 1, just to see what happens? The FLs seem to be the main driver for your pressure changes, which are not effective in addressing the FLs.

Also, which mode are you using on the ResMed machine?

[zonker]

but i think psychologically i feel better on a machine that shows me with a regular low ahi, that's for sure.

This is the most important statement in the two posts.



And with the two sets of numbers both under 1, sleeping better because of a greater comfort level should be a priority.

yup. a part of my brain realizes that under 1 for an ahi, without regard to the specific number, is pretty much equal. but the dumb part of my brain wants that lower number, cuz lower iz more betterer. so just knowing that oscar is going to report a lower ahi, with event numbers to prove it, is very gratifying.

Having said that, I believe the difference between the ResMed and the Respironics machines isn't necessarily that you are experiencing *more* hypopneas on the ResMed. Instead the difference between the two devices is the accuracy of them to detect an Hypopnea.

and here's where my lovely dream unravels a bit.

You are giving them both the same ability and accuracy to detect events. And that may not be true.

most certainly. my "argument" is, if i drive down the street in my 2014 subaru and i see a speed limit sign of 35 mph, i glance at my speedometer to make sure i'm at 35 mph. if i borrow my friend's 2014 f150 pickup truck and drive that same route, i expect things to be equal and not have to rely on any mental gymnastics to calculate what the speedometer says and thus make adjustments.
but by reading the study you linked, i begin to see that there is NOT an over riding set of rules that says that resmed and philips HAVE to adhere to the same calibration.

This study is a little old, from the RemStar/S8 days, but it compares CPAP devices ability to accurately detect events.



https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3767059/

this is certainly a thought provoking and eye opening article. it's not that this is strictly new info. both pugsy and palerider (and other, i'm sure.)have said similar things regarding the algorithms of the brands being different. it's just not anything i ever dwelled on before having it in black and white before my eyes.

from the article:
"In this study of home-based PAP efficacy, as measured by the S8 APAP device, the PAP-scored HI was on average more than double the manual-scored HI."

or in nonscientific terms, WOW!! that's some difference.

further:
"Given the importance of PAP efficacy data in tracking treatment progress, it is important to recognize that this particular APAP device may overscore hypopneas. The most likely causes of this discrepancy are (a) the use of a proprietary algorithm and (b) the use of desaturations in manual hypopnea scoring."

and:
"One previous study that used the S8 device also found relatively good apnea measurement but an overscoring of hypopneas [16]. That study found that the PAP HI was 3.3 times higher than the manual HI, and the resulting AHI was just over two times greater. "

all good stuff. but, in the end...

What do you prefer?

honestly?

i prefer not to have to think about it.

[zonker]

DS has a really interesting and informative perspective on this! A few other thoughts.

Given that we can see a flow limitation graph for the ResMed machine, and that it's pretty active, have you considered setting your minimum to 19 and using EPR of 1, just to see what happens? The FLs seem to be the main driver for your pressure changes, which are not effective in addressing the FLs.

Also, which mode are you using on the ResMed machine?

it's unlikely that i'll do that, tbh. i'm going to stay with the system one, for the time being. when it too breaks down and no longer functions, i'll setup the "for her" and go from there. i hope that the death of my system one is far in the future. and i hope you are here to help me out with it then!

oh! i don't remember which mode i was in on the "for her". sorry.

[Pugsy]

That old S8 algorithm and hyponeas always being higher really isn't something we can use today.
Some people had higher hyponea count with S8 machines and some didn't. The algorithm underwent a total redo with the release of the S9 machine's way of doing anything.
The S8 models didn't offer us any way to examine anything up close (like flow rate or flow limitations) to have any hope of doing anything but making WAGs.

Apples and oranges comparison. Pretty much useless now.

The brain is a powerful tool...sometimes works to our advantage and sometimes it doesn't.

Did you ever think to look to see if the slightly higher hyponea count on the ResMed was a false positive arousal/awake flag?

[elsueno]

x

[Dog Slobber]

I recognize that the S8/RemStar algorithms are old and compared to modern devices it is an apples to oranges comparison.

But the point was, and still is, our devices still do have discrepancies between apnea detection. While pretty darn accurate, they aren't 100% accurate. There will be detection differences between manufactures, and that very well could explain the difference between two devices.

We know that our machines are no substitute for abilities of polysomnography equipment used in sleep studies. So why would we think they should report identically?

Seems like a better explanation that he's actually experiencing more events, even though they are both pushing the same pressures, and he is consistently experience higher AHI on one, but not the other.

[elsueno]

x

[zonker]

Did you ever think to look to see if the slightly higher hyponea count on the ResMed was a false positive arousal/awake flag?

i'm not entirely sure. was going to look at my previous thread, which i'd saved the link to. unfortunately, that link has the dreaded redirects error!

can't remember if you'd given me that advice there.

if you'd like to, please tell me again. i'm still fairly certain i'm just going to stay with the system one. but if you and miss e have things for me to experiment with, i might set the for her back up and have a go.\

[Pugsy]

Doesn't matter to me which machine you use but just because the ResMed flags an event doesn't mean it was a real asleep event.

Here's an example of mine from not long ago. 3 events...OAs...but I wasn't asleep during any of them.

Have you ever looked to see if the more than you want hyponeas flagged by the ResMed are real asleep events?
That's all I am asking.

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[zonker]

Have you ever looked to see if the more than you want hyponeas flagged by the ResMed are real asleep events?

no.

[palerider]

yup. a part of my brain realizes that under 1 for an ahi, without regard to the specific number, is pretty much equal. but the dumb part of my brain wants that lower number, cuz lower iz more betterer. so just knowing that oscar is going to report a lower ahi, with event numbers to prove it, is very gratifying.

Ah, the dreaded 'chasing zero' diminishing returns activity

[zonker]

yup. a part of my brain realizes that under 1 for an ahi, without regard to the specific number, is pretty much equal. but the dumb part of my brain wants that lower number, cuz lower iz more betterer. so just knowing that oscar is going to report a lower ahi, with event numbers to prove it, is very gratifying.

Ah, the dreaded 'chasing zero' diminishing returns activity

meh. not so much CHASING as "strolling leisurely" towards zero.