wildly jagged flow rate curves -- do you see this in your data?

[Geer1]

Doctor will not do anything and can't see this data without your SD card data and even with that probably won't look at it.

At current settings you don't have this issue so why so worked up about it? Just keep using 4+ PS and nothing to worry about.

[cathyf]

The A10 that my insurance paid for 7 years ago has close to 20K hours on it, and Apria has ordered an AirSense 11 for me and their estimate is that I should have it in another 10 days - 2 weeks. And I have to figure out how to deal with the new machine, and with Dr SelfImportant, and with the insurance company.

I figure that if I'm going to be a patient then I have to give these people the benefit of the doubt and at least try the treatments that they prescribe and collect data before I decide to go dial-winging it on my own. And then when I do go off on my own I feel that I need to have all my ducks in a row and be able to explain why I'm doing what I'm doing.


I'm predicting that when the A11 comes, I'm going to use it with the prescribed settings and it's going to be pretty much a sh*tshow. The flow rate will show the fluttering pattern sometimes, and the sustained flow limits, and clusters of events. Then I'm going to go dial-winging and use everything I know and everything that I can learn and make my best shot at making the machine work -- and  maybe it will work? Maybe the ForHer algorithm with EPR=3 will work as well as the vauto with PS=3? But it probably won't -- the autoset algorithm on the A11 will be as worthless to me as the autoset algorithm on the A10. And the ForHer algorithm won't be any better. Dr SelfImportant will tell me the exact same thing about the sh*tshow that he says about the autoset 10 sh*tshow -- which is that my AHI is less than 5 and I'm mentally ill for wanting them to treat me any differently.

At that point I'm going to return the A11 to Apria before the end of the year and use my vauto.

[cathyf]

Ok, I found a journal article which looks very on-topic!

   https://erj.ersjournals.com/content/50/3...f_ipsecsha


I kind of chuckled at the pictures, though -- if I'm following, their characterization of "severe" looks like my "calmer periods between the peak craziness"!

[2SleepBetta]

I scanned the piece you linked about epiglottic collapse.

First, a few immediate observations about the piece:

-It's not clear any test subject had any marked dips below zero-axis between full exhalations, as you so often exhibit.

-The pathological curves do not share the early Ti-time spike/peak that is so prominent in the NED examples and in significant runs you have of those that evolve, within a Ti, to the scooped pattern. 

-One of my recently linked items above also shows differences various airway orientations make on the waveforms--there are positioning signatures, to some extent, in differing wave shapes.


In my opinion, worth all you paid for it:

-You may have more than one troubling collapse site with compounding effects.

-You have extensively (sufficiently for AB?)  documented the range of waveform aberration and their persistence.

-You have good reason to document your case for MDs and DMEs as you seek a VAuto, not another Autoset, from them.

-It could be a fool's errand, but I believe similar efforts of yours, and of all those here (there is lots of expertise-not in me) you can engage fruitfully. Look at changes/transitions into, if not changes out of (maybe, do that later), your various aberrant waveform patterns. 

As you know, I harp on needs for zoomed (2 min. x  3/4 to 1 in. amplitude). Researchers studying these things and looking for results and answers, will pick out single waveform specimens, ones most representative of significant runs of deformities vs experimental dosages. The research literature, beginning with bio mathematician Tero Aittokallio in Finland, have, little by little and more and more, related waveform shapes to airway mechanical and airflow qualities.

The simple degenerate sigh waveform I posted above, was my first stumbling real effort to relate mask pressure mis?- timing to waveform with its clear single drop below 0-axis between exhalations . It seemed that the slight waveform-pressure timing error(?) in a few waves repeated. 

As you and pholynyk (re pressure) have pointed out, (1) observed mask leak needs to be coherent with FR and FL to reach conclusions, (2) variable mask pressure modulating a co-varying leak flow rate and volume is all we at AB have to work with, (3) chest-strap info would be a great help. I would add that, given the mandatory, high-enough collar, it would be most helpful to know when you are supine or lateral.

You have also raised the  possibility that inflation and sudden deflation of cheeks might explain your sub-zero within-Ti peaks. Intuitively, that's appealing, but it would surprise me the effect could be that large, even be repeated (correct?) within a single complete Te' s bounds. Accordingly, need for the strap; maybe close inspection of FR wave and pressure wave+ would suggest something.

[Geer1]

As S2B states your breath waveforms bounce into negative flow rate not just a level of restriction/obstruction. I still think this is is muscle related and will only truly know by recording yourself during it but not a whole lot of point in that unless say you get this same issue with the Autoset 11 and then record and show the video to doctor saying this is why the Autoset is not good enough.

No way this is air in cheeks. At some points it is irregular but at others it gets into a bit of a rhythm and pulse less than a second. Try to imagine what that would look like if it was your cheeks moving. It wouldn't be air escaping into mouth, it would have to be cheek tremors or something along those lines.

Oscar data won't get doctor to change any of his minds on this. Your only luck if trying to convince doctor you need a vauto is more obvious proof of an issue like video recording.

[cathyf]

Found an even more interesting article by the same University of Queensland researchers 
Especially good is after you read through it find the link to the supplementary pages— lots of interesting figures 

These guys sound like us!

https://erj.ersjournals.com/content/54/1/1802262
[url=https://erj.ersjournals.com/content/54/1/1802262][/url]Quantifying the magnitude of pharyngeal obstruction during sleep using airflow shape

[SarcasticDave94]

To be honest, I've not kept up with your journey, mostly because of my own PAP therapy battles. This thread recently mentioned you're getting an 11 series and running what's prescribed. If you know you've got a pressure set that negates your Apnea and sleep woes at least somewhat, and that it's going to be better than Dr. McQuack's random, oft ill-concieved cobble, keep that pressure set which works. The only real item regarding compliance is "Is the patient using the PAP for 4 hours nightly?" I don't even think whether it's successful comes into consideration, excepting the compliance face to face where you declare your therapy is helpful.

Hope all plays out well.

[2SleepBetta]

Thats a great find re wave shapes, Cathy, thanks. Add this related one to the tool box: Flow-Identified Site of Collapse During Drug-Induced Sleep Endoscopy (chestnet.org)

[cathyf]

Aha! I think that I know what's causing it! I set the vauto trigger to VeryHigh, and this is sleeping without a collar...

Here's the whole night --
   https://www.dropbox.com/s/96gw3qsfbkxfht...t.png?dl=0


Here's a zoom of the first episode:
  https://www.dropbox.com/s/12tat8pvh0b3wd...9.pdf?dl=0

I'm also more convinced that it's positional, because every shift looks like it's accompanied by movement...

I also will say that the VeryHigh trigger is pretty unpleasant to breathe against in every position, at least for me. It's like it puts the vauto into what feels like a resonance frequency with my airway...

I think that this also looks like the autoset EPR is doing pressure support with a VeryHigh trigger, and that's why it doesn't work nearly as well as the vauto at default settings for me, even at PS=3 on the vauto.

(Have I said before how utterly astonishing it is to me that the ResMed engineering is such an "idiot savant" combination of brilliant and stupid engineering? It's like they have no overarching theory of what they are doing that translates into a design.)

[cathyf]

Dave -- you posted this on tired4life's thread http://www.apneaboard.com/forums/Thread-...#pid419383

Getting the assist from EPR that Gideon mentions will be helpful. Also take special note of difficulty in staying synchronized in inhale to exhale patterns and timing with your PAP. If that becomes an issue, the BPAP VAuto or higher level machines with timing controls may be valuable.

And I didn't want to hijack t4l's thread so I'm asking over here.

What do you mean by "difficulty in staying synchronized in inhale to exhale patterns and timing" ?

This thing that I'm talking about where my flow rate curve gets wildly jagged -- I would also describe it as the PAP can't stay synchronized to inhale and exhale. When it is going on the PAP gets utterly bewildered by whether I'm inhaling or exhaling and reports a ridiculous respiration rate. In my case I believe that it's positional, and it happens in a position that's impossible when using a cervical collar, because I'm pretty sure that I've never seen it when wearing a cervical collar. I can now produce/prevent this reproducibly.


Jagged breathing possible:
-- NOT wearing cervical collar
AND any of the following four scenarios:

1. autoset with no EPR
   
2. autoset with any EPR (the mask pressure curve is a strong visual indication of just how confused the machine is)
   
3. vauto with PS=0
   
4. vauto with PS=4 AND trigger set to VeryHigh
   

Jagged breathing has never happened in any of these scenarios:

1. autoset WITH cervical collar, EPR or no EPR, OR
   
2. vauto WITH cervical collar, any settings, OR
   
3. vauto withOUT cervical collar, PS=4, trigger set to medium (which is the default.)
   

I've got quite a few nights on the vauto with the combination of no collar, PS=4, trigger medium. I definitely get into some short clusters of positional apnea without the collar, but never the wild jaggy breathing.

My working hypothesis is that there is some position that I can get into without the collar, and frequently do get into without the collar, and this position sets up some resonance frequency in the geometry of my airway. Then EPR/PS "damps" the resonance -- but only when the trigger sensitivity on the pressure support is set to the vauto default of medium. I'm pretty sure that the Autoset's EPR, which doesn't have a trigger sensitivity that you can set, is running with the equivalent of the vauto's VeryHigh trigger. With the VeryHigh trigger, the pressure support oscillates at very high speed (which I can see in the mask pressure curve) and it can't damp the nasty oscillations.

(For the world's most famous example of a catastrophic resonance, see the Tacoma Narrows Bridge failure. https://www.youtube.com/watch?v=mXTSnZgrfxM )