Hitting Max Pressure With Controlled AHI Question

General Discussion on any topic relating to CPAP and/or Sleep Apnea.
Franko39
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Hitting Max Pressure With Controlled AHI Question

Post by Franko39 » Fri Aug 23, 2024 11:49 am

Hi everyone,

Thanks again for the helpful tips for a beginner. It's been a good 8 months of therapy and I think I've finally started to get a handle on things. My leak rates have lowered a lot (thanks to the F30i mask) and I'm able to sleep through the night with the CPAP on most nights. Most nights on therapy, I'm hitting an AHI score between 2-3. I was diagnosed with mild OSA and an AHI of 10 untreated.

In reviewing my OSCAR data, I'm seeing a trend that I am hitting the ceiling of my pressure range (6-10.6) for a 2-4 hours/night on average. Would you recommended increasing the max pressure as such?

I've heard mixed things about pushing too hard on the pressure due to CAs, etc. Since my AHI is pretty good as-is and I'm sleeping well, I'm not sure how necessary it is to further raise the max pressure to reduce the time spent where the machine is "capping out".

TIA!

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zonker
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Re: Hitting Max Pressure With Controlled AHI Question

Post by zonker » Fri Aug 23, 2024 11:55 am

Franko39 wrote:
Fri Aug 23, 2024 11:49 am


I've heard mixed things about pushing too hard on the pressure due to CAs, etc. Since my AHI is pretty good as-is and I'm sleeping well, I'm not sure how necessary it is to further raise the max pressure to reduce the time spent where the machine is "capping out".

TIA!
and you're going to no doubt hear from people in two camps here. i've always left my pressure at the max figuring while I don't ALWAYS need it, it's handy just in case I do. i haven't had any ca's since my first few months of therapy. or at least, not so many as to be concerned about.
people say i'm self absorbed.
but that's enough about them.
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Miss Emerita
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Re: Hitting Max Pressure With Controlled AHI Question

Post by Miss Emerita » Fri Aug 23, 2024 12:01 pm

Good idea from Zonker! I'd be curious to see a recent and typical Oscar chart, if you could post one.
Oscar software is available at https://www.sleepfiles.com/OSCAR/

Franko39
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Re: Hitting Max Pressure With Controlled AHI Question

Post by Franko39 » Fri Aug 23, 2024 12:34 pm

You bet! Please see attached for a recent night. This is a good example of a typical night for me - some occasional minor leaks (likely from tossing and turning), some time spent hitting the max pressure ceiling, the odd false "CA" from arousal.

Any inputs would be much appreciated!
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Pugsy
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Re: Hitting Max Pressure With Controlled AHI Question

Post by Pugsy » Fri Aug 23, 2024 2:02 pm

Have you ever tried a having a little more max pressure available?

If you did...what happened? If not...maybe try it.

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Franko39
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Re: Hitting Max Pressure With Controlled AHI Question

Post by Franko39 » Tue Aug 27, 2024 11:44 am

Pugsy wrote:
Fri Aug 23, 2024 2:02 pm
Have you ever tried a having a little more max pressure available?

If you did...what happened? If not...maybe try it.
I'll try that tonight and see what happens!

Another user on another forum had suggested that my issue might be with flow limits and had advised against increasing the max pressure. Just wanted to get a second opinion as to how bad my flow limitations really are - here is my OSCAR chart from last night for reference.

Again, much appreciated!
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chunkyfrog
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Re: Hitting Max Pressure With Controlled AHI Question

Post by chunkyfrog » Tue Aug 27, 2024 12:01 pm

Leaving the max at its highest woke me up too often;
so I sleep better with nice, comfy brackets.
Like side rails on my lily pad. :mrgreen:

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Pugsy
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Re: Hitting Max Pressure With Controlled AHI Question

Post by Pugsy » Tue Aug 27, 2024 2:38 pm

Are you having any nasal congestion during the night?
If not.....try increasing your EPR to 3 and see what those flow limitations look like with more pressure support maybe helping out.
If you are having much nasal congestion we have a different discussion.

Though your flow limitations aren't horrible. I have seen much worse.

Here's really, really horrible.

Image


Here's what my own FLs look like.....pretty much non existent.

Image

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Franko39
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Re: Hitting Max Pressure With Controlled AHI Question

Post by Franko39 » Tue Aug 27, 2024 4:31 pm

Pugsy wrote:
Tue Aug 27, 2024 2:38 pm
Are you having any nasal congestion during the night?
If not.....try increasing your EPR to 3 and see what those flow limitations look like with more pressure support maybe helping out.
If you are having much nasal congestion we have a different discussion.

Though your flow limitations aren't horrible. I have seen much worse.
I've been having nasal congestion and some loss of smell, yes. I tried increasing EPR to 3 recently, but my CAs went up significantly (AHI up to 4-5), without a huge drop in the flow limit changes. Please see attached image for my experiment with EPR at 3.
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Pugsy
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Re: Hitting Max Pressure With Controlled AHI Question

Post by Pugsy » Tue Aug 27, 2024 5:14 pm

Were you for sure sound asleep when those centrals/CAs were flagged?
Do you know how to tell the difference between asleep and awake/arousal breathing?

If EPR is for sure the cause of more centrals (I am not so sure just yet) then you can try increasing the minimum pressure just a little bit and see if it helps reduce the FLs.

You might want to read this topic and look at the examples I posted.
viewtopic.php?f=1&t=187767&p=1451526#p1451526

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Franko39
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Re: Hitting Max Pressure With Controlled AHI Question

Post by Franko39 » Tue Aug 27, 2024 5:21 pm

Pugsy wrote:
Tue Aug 27, 2024 5:14 pm
Were you for sure sound asleep when those centrals/CAs were flagged?
Do you know how to tell the difference between asleep and awake/arousal breathing?

If EPR is for sure the cause of more centrals (I am not so sure just yet) then you can try increasing the minimum pressure just a little bit and see if it helps reduce the FLs.

You might want to read this topic and look at the examples I posted.
viewtopic.php?f=1&t=187767&p=1451526#p1451526
I ran my "CA" events by some other forum members (I think you also provided me some assistance) and was assured that my events weren't "true" CA events. Moreso events related to arousal.

However, it's weird that I had so few of these events normally, but developed so many when I set EPR to 3 (I also felt more tired after the EPR 3 experiment).

Thanks for the additional tips. I'm going to try increasing my max pressure from 10.6 to around 11.2 to see if there's any difference in the FLs (I've set my EPR back to 1, after the trial at 3). I've just finally got the hang of things after months of struggling with different masks, leaks, etc, so I just want to tread carefully with my tweaks.

Thanks again for the tips - I'll report back soon.

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Dog Slobber
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Re: Hitting Max Pressure With Controlled AHI Question

Post by Dog Slobber » Tue Aug 27, 2024 6:03 pm

Franko39 wrote:
Fri Aug 23, 2024 11:49 am

I've heard mixed things about pushing too hard on the pressure due to CAs, etc.
CPAP induced Centrals because of high pressures only affects a small percent of the population.

There's nothing in your charts that suggests it's a problem for you.

Avoiding trying higher pressures because a small percentages of the population may be impacted, is like avoiding trying lobster, crab and shrimp because a small percentage of the population are allergic to shellfish.

I'd also suggest that you increase your minimum pressure.

Looking at the timing, frequencies, flow limitations, and abruptness of your pressure increases, your a candidate for more significant OAs during REM. And since your pressure has too far to go to treat your REM OA it's responding hard and late.

I'm betting, if you increase your minimum. it will flatten your trace and reducing the need to go as high.

Set your pressure to 8 or 9 and see if the high end flattens out.

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ozij
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Re: Hitting Max Pressure With Controlled AHI Question

Post by ozij » Tue Aug 27, 2024 9:31 pm

Franko39 wrote:
Fri Aug 23, 2024 11:49 am
Since my AHI is pretty good as-is and I'm sleeping well, I'm not sure how necessary it is to further raise the max pressure to reduce the time spent where the machine is "capping out".
You're sleeping well
Your flow limitation only appear every now and then, causing the machine to raise its pressure. And then the pressure drops. Even at the very top, you're not really "stuck at the top".

I'm not sure you have to make any changes, but if any, I would try raising the minimal pressure just a bit. Take the cursor, point it at each time the flow limitations start and check the pressure. Maybe, if you keep the machine from going there, flow limitations won't even start.

Higher EPR can induce CA's because it causes easier clearance of CO2, and too low a level of CO2 delays our inhalation, our brain simply waits for CO2 to accumulate because that's what tells the brain inhalation is needed.

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Franko39
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Re: Hitting Max Pressure With Controlled AHI Question

Post by Franko39 » Fri Aug 30, 2024 10:20 am

Thanks for the feedback everyone. I tried raising the pressure range to 7.0-11.2 (from 6.0-10.6) - attached are my OSCAR graphs. There doesn't appear to be much change in anything overall. The flow limits may even be worse at this setting, from a quick glance. Thoughts on how to proceed?
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zonker
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Re: Hitting Max Pressure With Controlled AHI Question

Post by zonker » Fri Aug 30, 2024 12:01 pm

Franko39 wrote:
Fri Aug 30, 2024 10:20 am
Thoughts on how to proceed?
patience. much patience. my suggestion is to leave this for a few days and see how it goes.
people say i'm self absorbed.
but that's enough about them.
Oscar-Win
https://www.apneaboard.com/OSCAR/OSCAR-1.5.1-Win64.exe
Oscar-Mac
https://www.apneaboard.com/OSCAR/OSCAR-1.5.1.dmg