New sleep study coming... some questions about moving to bi-level

I'm having good (really good) numbers with 15cm and EPR 2... some nights zero AHI even. Humidity/hose manual at max.

I use Oscar and O2Ring religiously. Looking at my waveforms I'm still seeing weird flow limits, like 'scooping' or devil horns, on top of my breaths for much of the night. I'm attributing these to flow limitations that the machine is not catching (AS 10 Autoset with 2015 firmware) or is incapable of correcting. Here's an unlisted video:

https://www.youtube.com/watch?v=JO1TwKB8Sn4

It's been 14 years since my first study (AHI over 100 and a 10cm prescription) and it's time for a new one anyway. I have self-titrated up to here. I have access to an Aircurve 10 vAuto.

I talked to my provider and the one split-night study insurance is paying for won't cover bi-level titration... and the doctor won't prescribe bi-level unless the study comes back with improvement needed... at which time I will have to come in for a separate bi-level titration.

Somehow I got it into my head that labs can titrate for both in one study. Is this just not a thing, during a split night? Is it normal to go back in? I'm guessing that a bi-level would be better treatment for me, just trying to cut to the chase. I've had other nights where the pressure never got over 16cm.

That ain't a hypopnea. That's palatal prolapse (OK the machine don't know palatal prolapse, so you can't blame it).

What does "flow rate set to dynamic" mean?

Can you put the Mask Pressure graph right under the Flow Rate?

vandownbytheriver wrote: ↑

Wed Feb 07, 2024 3:35 pm

Somehow I got it into my head that labs can titrate for both in one study. Is this just not a thing, during a split night?

Well, they absolutely could do everything in one night, and frequently do.

At least used to anyway. The current Treatment of Adult Obstructive Sleep Apnea with Positive Airway Pressure: An American Academy of Sleep Medicine Clinical Practice Guideline (2019) is not real big on slapping everybody on BiPAP. You need to get the coverage document from the insurer, the sleep center's titration protocol, and the specific order of the physician.

Rubicon, is the palatal prolapse mainly on the left-most part of the flow rate that the video shows? Do the "devil horn" shapes at the tops of inhalations further to the right look like flow limitations?

To the OP: it's certainly technically feasible to do a one-night titration with emulation of several kinds of machines, but your insurance isn't going to pay for it. And it sounds as though your doctor will in any case not prescribe a different machine for you simply on the basis of changes in your flow-rate trace.

So a couple of questions: Do you feel rested during the day? Why is your EPR set at 2 rather than 3? And if you have access to a bilevel machine, do you feel like experimenting with it?

Miss Emerita wrote: ↑

Wed Feb 07, 2024 4:48 pm

Rubicon, is the palatal prolapse mainly on the left-most part of the flow rate that the video shows?

Yup. The exhalation stops abruptly.

Do the "devil horn" shapes at the tops of inhalations further to the right look like flow limitations?

Also yup, but IMO you have to look at what the machine is doing when in any type of bilevel mode to make sure the waveform isn't a product of the machine (probably not, but the waveform was fine (except for PP), then clearly an arousal, perhaps even to wake, then wicked FL with higher pressure?) Need more info.

Thanks!

Rubicon wrote: ↑

Wed Feb 07, 2024 4:28 pm

That ain't a hypopnea. That's palatal prolapse (OK the machine don't know palatal prolapse, so you can't blame it).

Not what I wanted to hear, obviously... resection? Ouch! Saw an ENT, showed him the graphs, he said 'tongue' and said let's see what happens with the new study.

What does "flow rate set to dynamic" mean?

In Oscar you can double-click the Y axis to free it from accommodating the highest reading of the night... that way when you zoom in, the graph is filled by the waveform. When you change zoom the graph expands... watch the axis gnomon on the left, the max/min will change. I did it to help the crappy phone video with resolution, hope I didn't confuse anyone.

Can you put the Mask Pressure graph right under the Flow Rate?

Easy to do... turns out I have a barely used login to Google Photos... used it nine years ago and forgot until I searched for a hosting service. Here's a link showing the event, I think this is what you wanted to see.

https://photos.app.goo.gl/Y5swdNSzTV2aWuZr7

Note I have dynamic turned on for both Flow and Mask Pressure. Thanks for your help btw.

vandownbytheriver wrote: ↑

Thu Feb 08, 2024 1:12 am

In Oscar you can double-click the Y axis to free it from accommodating the highest reading of the night...

Got it.

hope I didn't confuse anyone.

Nah, I'm probably the only one who never clicked that button.

So are your "horns" you or the machine?

And are you awake or asleep (cause if you're awake analysis would be an exercise in futility).

Anyway:

I wouldn't make any major life decisions based on 16 breaths when there are 5184 other breaths that need a look-see, so you could load that file to SleepHQ for a better assessment;

An issue with SleepHQ is that you can't view Mask Pressure so to see something like above you'd have to upload the Oscar file to Dropbox or similar to be reviewed;

Find a night or make a night with EPR off. IMO your FLs might be a result of an arousal F/B resuscitative breathing, with EPR needing another split second to equilibrate. You'd need to similarly micro-analyze Pressure.

That's all I got...

Rubicon wrote: ↑

Thu Feb 08, 2024 5:09 am

That's all I got...

Valid points... thanks. EPR is trying very hard, over a very short time... and it's having to guess... and it's set to one-size-fits-all algorithm and tuning. Bi-level would have much better tunings available.

So we'll go with straight 15cm with APAP up to 20cm for tonight. Thanks again Rubicon.

Vandownbythe river, I'm still curious about your answers to these three questions:

Do you feel rested during the day? Why is your EPR set at 2 rather than 3? And if you have access to a bilevel machine, do you feel like experimenting with it?

Miss Emerita wrote: ↑

Thu Feb 08, 2024 12:58 pm

Vandownbythe river, I'm still curious about your answers to these three questions:
Do you feel rested during the day?

Sometimes better, sometimes worse... like today I was nodding off. Sometimes when I wake I just want to go back to bed... get up and pee, fill the tank, and sleep another three hours. I've been doing that about twice a week lately.

Why is your EPR set at 2 rather than 3?

Trying to wean myself... going to try going down 1cm with no EPR tonight. As Rubicon wrote, EPR is kind of a hack... there's no tuning to it, it's just one algorithm. Lanky Jason hates it, he'd much rather titrate using bi-level... if EPR is all he has to work with, he'll use it. Now that I look at the horns on my waveforms I'm seeing that I might be fighting EPR. I'll post back tomorrow with tonight's results.

And if you have access to a bilevel machine, do you feel like experimenting with it?

I tried that and had a bad night... quit after four hours. Not sure how to set the thing. PS has me confused I guess. Big changes are not helpful I've found! Fighting a position-dependent OA that appears to be tongue-related... supine is bad, but on left side not much better. On my right side is definitely best... but I have to switch sides for comfort. Even though I'm on full-face mouth taping seems to help... prevents jaw-drop, or at least lessens it. I ordered and paid for a Knightsbridge from the manufacturer... ended up cancelling that order, they are just too screwed up what with all the copyright/takeover/etc. I did find the chinstrap I wanted at another supplier and it should be on the way soon. I do have an overbite, maybe a boil-n-bite would help? Anyway...

I have a new sleep study tomorrow night... I'll talk to the tech and see if they're amenable to recommending bi-level settings informally... probably not, eh? The company wants to study a whole separate night for bi-level titration. I've been on CPAP for 14 years by now... but I'm going to have to do four hours of torture before going on the hose... *that's* not going to be fun.

Thanks for your interest.

This is an interesting Uncle Nick video about Resmed EPR...

https://www.youtube.com/watch?v=GaXA0ZIWj1Y

Evidently not a good algorithm... Lowenstein has the good one!

vandownbytheriver wrote: ↑

Thu Feb 08, 2024 10:48 pm

This is an interesting Uncle Nick video about Resmed EPR...

https://www.youtube.com/watch?v=GaXA0ZIWj1Y

Evidently not a good algorithm...

Meh.

I'm glad "Uncle Nick" has finally caught up after 18 years, but the problem with the EPR algorithm was exposed by our very own, and world famous, poster, deltadave, before EPR even hit the market.

On September 11, 2005, he posted:

My point still remains that if EPR is carried throughout the expiratory cycle to the point of inspiration, then the only possible trigger could be negative inspiratory pressure at a now-subtherapeutic level. This would mean that the only time the patient would see his prescribed pressure would be during the inspiratory phase. A whole new EPAP has been established, and call it BiPAP, Bilevel, or whatever, but by definition, it's not CPAP. And if you aren't at therapeutic CPAP level prior to inspiration, some people are going to have an issue with that.

For example, let's say your CPAP is set at 15 cmH2O. You put your EPR at 3 cmH2O. If negative inspiratory pressure is the trigger for resumption of CPAP level, that's another 1-2 cmH2O anyway, so at the critical point where the OSA occurs, you're only at 10-11 cmH2O.

viewtopic/t4514/ResMed-S8-Vantage-EPR.html?start=15

vandownbytheriver wrote: ↑

Thu Feb 08, 2024 8:38 pm

Now that I look at the horns on my waveforms I'm seeing that I might be fighting EPR.

Now that WHO looked at your waveforms?

And are you awake or asleep (cause if you're awake analysis would be an exercise in futility)...

I wouldn't make any major life decisions based on 16 breaths when there are 5184 other breaths that need a look-see, so you could load that file to SleepHQ for a better assessment;

If all 5200 breaths looked like that, then you can make a case for "fighting" EPR. And you were "fighting" your BiPAP fiddlement (but since I have NFI what you were doing there could/was probably a parameters issue).

However:

Fighting is a function of wake.
Fighting is a function of wake.
Fighting is a function of wake.

Unless, of course, the parameters are set to FUBAR.

OK in this brief snippet:



I would guess "fighting" but I would also guess "wake" (at least EEG > alpha but we ain't got one of those).

Bottom green circle shows IPAP ~16.8 cmH2O, but top green circle show that a pressure of 18.2 cmH2O was generated-- 1.4 cmH2O above set pressure.

Now if you equate 1.4 cmH2O with fighting like you'd associate fighting in an Ali-Frazier event, then unnh-uh.