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Lots of Flow Limitations -- What's Going On?
#1
Lots of Flow Limitations -- What's Going On?
I think I have a flow limitation problem, but I need expert help to understand what's going on, whether it really is a problem, and how to fix it if it is a problem.

Here's last night, which is fairly typical for me -- low AHI but lots of flow limitations all night long:

[attachment=11243]

Here's a close-up of a typical stretch of breaths:

[attachment=11244]

Should I be concerned and adjust my settings to address the flow limitations, or leave well enough alone?  My AHI is almost always between 1.5-2.5; it's sometimes lower, like last night, and sometimes higher, but it's virtually always under 5.  I've been using my APAP faithfully ever since I was diagnosed almost 4 years ago.  My sleep doctor thinks I'm doing great, and I feel good.

I've changed my pressure and EPR settings here and there to see what that would do, but as far as I can tell there has been no impact one way or the other on flow limitations or breath patterns.

Experts out there: can you give me your thoughts?

Thanks,
AndyB
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#2
RE: Lots of Flow Limitations -- What's Going On?
As you said lots of flow limitations, but with good numbers.
With good numbers I do recommend that changes be based more on how you feel, and not the numbers.

I'm going to suggest setting EPR to 3 to help knock down those Flow Limitations.  Pressure Support is what is used to treat Flow Limitations on a BiLevel and EPR is very similar to PS.  We should also increase your pressures by 1 to maintain the same therapeutic value.  As with any change in settings, try, evaluate, then modify if necessary.
Make sure that your flag for RERA is set on (drop down on the lower left of the graphs).  The close up you provided is almost a classic example of a RERA, the only thing missing is the arousal at the end.

Here is a good chart showing a RERA with the arousal at the end.
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#3
RE: Lots of Flow Limitations -- What's Going On?
Fred -- thank you very much for your fast and helpful response.  I will do as you suggest, and report back after a few days of treatment with the adjusted settings.

RERA flag is on -- guess my machine didn't count it as an event worth recording.

By the way, I don't see a chart attached to your message -- am I missing something?

Thanks,
AndyB
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#4
RE: Lots of Flow Limitations -- What's Going On?
Thyis

http://www.apneaboard.com/wiki/index.php...erapy#RERA
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#5
RE: Lots of Flow Limitations -- What's Going On?
Fred -- here's an RERA from 2 nights ago that my machine flagged.  I assume what happened here is the "classic" RERA breath pattern you referenced and is shown in the Wiki example, yes? Just trying to read the chart better . . . 

[attachment=11247]
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#6
RE: Lots of Flow Limitations -- What's Going On?
Pretty classic, The question is how often do you have something similar on the nights but not as severe on the arousal. Note That RERAs are scored by noting a drop in the flow rate (think hypopnea like) over a fairly brief period of time (Minutes) BUT if you have the drop for a longer period of time before the arousal a RERA Event will not be scored because the machine assumes that the reduced "level, is your new normal and therefore you are NOT experiencing a reduction. RERAs need to be manually checked for this reason especially if you see long stretches of Flow Restrictions as I see in your charts.
FYI it is always good to have the zero redline on the FlowRate shart, it separates the inhale from the exhale. (Inhale above)
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#7
RE: Lots of Flow Limitations -- What's Going On?
Thanks for your continued help Fred.

I have numerous (really almost constant) flow limitations every night, but usually very few or no RERA events are flagged.  Here are 3 recent nights that are typical:

[attachment=11263]

[attachment=11262]

[attachment=11264]

And here is a representative close up of a high flow limitation that was not flagged as an RERA.

[attachment=11265]

This is very interesting stuff -- thanks for sharing your expertise.

AndyB
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#8
RE: Lots of Flow Limitations -- What's Going On?
In addition to the charts above, here's another typical example of a high flow limitation that didn't trigger an RERA event, and also was not followed by a significant arousal, as seems normally to be the case for me (i.e., no arousal).  Mysterious . . . (at least to me).

[attachment=11266]
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#9
RE: Lots of Flow Limitations -- What's Going On?
Andy, I agree with Fred. You clearly have persistent flow limitations and with your current tool, the Airsense 10 Autoset, you are limited to 3 cm of pressure support (EPR). You should definitely set the EPR to 3, but the ideal answer for you may be the higher pressure support from a bilevel machine like the Aircurve 10 Vauto. Insurance is unlikely to agree, but here are a couple wiki articles that show bilevel is generally more effective. At least you have the Autoset which is much better than other alternatives.
http://www.apneaboard.com/wiki/index.php..._and_BiPAP
http://www.apneaboard.com/wiki/index.php...Limitation
Sleeprider
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#10
RE: Lots of Flow Limitations -- What's Going On?
(04-09-2019, 07:10 PM)Sleeprider Wrote: Andy, I agree with Fred. You clearly have persistent flow limitations and with your current tool, the Airsense 10 Autoset, you are limited to 3 cm of pressure support (EPR).  You should definitely set the EPR to 3, but the ideal answer for you may be the higher pressure support from a bilevel machine like the Aircurve 10 Vauto. Insurance is unlikely to agree, but here are a couple wiki articles that show bilevel is generally more effective.  At least you have the Autoset which is much better than other alternatives.
http://www.apneaboard.com/wiki/index.php..._and_BiPAP
http://www.apneaboard.com/wiki/index.php...Limitation

Fred and Sleeprider -- I am very grateful for your generosity of spirit and expert advice.  I'm amazed at the knowledge you both possess, and by your willingness to share it with the lucky folks like me who have found this incredible community.  THANK YOU!

AndyB
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