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Check the IFL1 (Inspiratory Flow Limitation 1) on that one SAG. It's probably on - when it should be off for this person - who has many runs of inspiratory flow lmitations -- which apparently are his (her?) normal breathing pattern and therefore can't be corrected by further pressure.

Edited addition: The IFL1 parameter instructs the PB to raise pressure in response to inspriatory flow limitation RUNs - so it does. [end of edit]

Note the way the pressure dips when the runs disappear, both at the begining and after the first hour.
O.

StillAnotherGuest wrote: Wha?

OK, whadya do with them other 3 apneas?

SAG

Ask not what I did with them apneas (I'm a well know witch in my close circle...) ask rather what Silverlining did with them.

Them 3 apneas are the ones the have an apnea/CA beneath them. The session of rested gal's has but one honest apnea, just where the pressure starts rising for the first time.

We have a "something or other aka mixed apnea or jabberwock" before that real apnea, another one at the height of a leak (when all that CA drama starts) and a third one during that apnea/CA drama.

Those only get calculated into the "apnea/CA" number.

O.

If the "this one" is the same guy as (click here to go to) "that one", the "that one" picture link seems to be broken.

SAG wrote:In all fairness to APAP algorithms the world 'round, it might be more appropriate to call this a design "limitation". The point of this one and RG's is that if you're trying to do diagnostics with single-channel data acquisition, there is a percentage of patients where major underlying disease states will be missed.

Are there PSG-scored apneas and hypopneas in that particular epoch the 420e missed?

I see pressure increases based on what the 420e thinks are flow runs (which are, interestingly, not always scorable flow limitations--by design).

Were people ever discussing the possibility of a flat earth?" I thought the issue was whether the earth can be considered spherical with so much pole-flattening and equatorial bulge.

Proposal: let's revisit loonlvr's case in a separate thread. In this thread I would like to revisit signal processing issues during Laura's 420e session during the PSG.

rested gal wrote:If the "this one" is the same guy as (click here to go to) "that one", the "that one" picture link seems to be broken.

AHA! Cause I knew you would try to peek at the answer, you PLM Vixen, you!

OK, that and the image server I used to use had issues.

Right, IFL1 was on, and never had a chance to see if turning it off would have made a difference. But that patient had CompSAS, and to have 420E even indirectly suggesting FL Runs was extremely misleading.

Omigod! Oregon lost! I can't believe that everything that needed to fall into place has actually happened!!

SAG

[quote="StillAnotherGuest]Right, IFL1 was on, and never had a chance to see if turning it off would have made a difference. But that patient had CompSAS, and to have 420E even indirectly suggesting FL Runs was extremely misleading.[/quote]

Why?
And what would it have been OK for the 420E to record in this case? And also, to repeat -SWS's question - what did the PSG show for that time period?

O.

ozij wrote:

StillAnotherGuest wrote:Right, IFL1 was on, and never had a chance to see if turning it off would have made a difference. But that patient had CompSAS, and to have 420E even indirectly suggesting FL Runs was extremely misleading.

Why?
And what would it have been OK for the 420E to record in this case? And also, to repeat -SWS's question - what did the PSG show for that time period?

This patient had severe CompSAS composed of obstructive, central and testbook mixed apneas that failed to improve with CPAP or BiPAP, but responded very nicely to ASV. And although this wasn't a direct comparison of NPSG against sleepware, events persisted throughout unstable NREM on NPSG (including titration), yet the sleepware reported few to no Apneas, ApneaCAs or Hypopneas during sessions that ran through the whole pressure range. The long-term cumulative AHI was absurdly low.

There was a significant central component, yet this was not reflected in any 420E data. Reporting out FL Runs sends one in an entirely different direction (obstructive, whether it's fixed or not) than you need to be heading.

SAG

OK, killing time till the game starts:

ozij wrote:Note the way the pressure dips when the runs disappear, both at the begining and after the first hour.

Good point there, o. But was the patient awake or asleep at that time?

ozij wrote:Check the IFL1 (Inspiratory Flow Limitation 1) on that one SAG. It's probably on - when it should be off for this person - who has many runs of inspiratory flow lmitations -- which apparently are his (her?) normal breathing pattern and therefore can't be corrected by further pressure.

And this really speaks to the heart of the matter, the real danger of falling into the NFI (No Further Improvement - we must be done here) rut.

If 10% of people have PLMs, and 15% of sleep lab patients have CompSAS, and God knows how many patients have some other sleep-wake disorder, how do you know that single channel data-acquisition tells you everything you need to know?

Here's the summary of FL Runs.

Which are benign, which are spurious, and which are malevolent?







So, a la roadside signs back in the day, when there also were "Danger, Brontosaurus Crossing" signs:

You can't fix a problem

If you don't what it is.

If you wing them dials around

Till you get the result you want

It's not necessarily

The result that you need.

Burma Shave.

And Boomer Sooner!!

SAG

SAG,
I did say apparently, and I was only pointing to the fact the under these conditions - the pressuer goes on and on on withoug beign able to make a dent in these flow limitations.

In my lexicon, "apparently" means "this it what it looks like here without further checking". Is that an incorrect use of the word?

If 10% of people have PLMs, and 15% of sleep lab patients have CompSAS, and God knows how many patients have some other sleep-wake disorder, how do you know that single channel data-acquisition tells you everything you need to know?

No of course not. Did you show all the data for that person? You showed a weird 420E snippet, and based on the I said - this is an IFL1 going wild, turn it off. Well, that's what I meant you to understand in what I said....

O.

Whoops!! Clearly I have generated a misunderstanding of the pronoun "you", being interpreted as "You" ("o") vs the more generic object, being "y'all".

I will repaint my roadside signs accordingly:

One can't fix a problem

If one don't what it is.

If one wings them dials around

Till one gets the result one wants

It's not necessarily

The result that one needs.

Hmmm. Seems to be a little choppy, I'll work on it.

But I do like the flow of

how do one know that single channel data-acquisition tell one everything one need to know?

Cause one never knows, do one.

SAG

Speakin' of flow....

Here are some more road signs from back in my day...updated:

If the pressure runs away

Turn off FL One

If the pressure still goes wild

Somethin' must be done

POLY WAVE