[Pressure] OA without Flow Limitation?

[SeePak]

lessgroggy

If you can provide the Tidal Volume on the chart it will help understand each event.

You will see how flow drops and how low it goes.

Your inhalation time goes up during the OA so for sure you had something going on there.

How is your sleep and rest?

Are you tired during the day?

Flow Limitation is somewhat controversial as you can find a lot of discussion around it on the web and here on this website.

Depending on the algorithm that each manufacturer uses, different machine reaction occurs.

I have been on CPAP for 35+ yrs, and only now becoming aware of FL.

Your interest at this stage is good, but don't get too hung up on it if you have good sleep and good numbers.

Your chart and numbers look real good, you seem to have a very mild sleep apnea condition.
Low pressure is taking care of your OA events which is awesome.
You may see your Tidal Volume go up while increasing your pressures.
This will lead to better FL numbers, and possibly better sleep.

I do admire your interest in this, just that others with far more experience and knowledge scratch their heads with FL as well!

Hope this helps?

[lessgroggy]

I managed to figure it out, I think. I noticed that my peak pressures were flattened out and unable to prevent the OAs, so I eyeballed what the peak might be if unrestricted and increased my max pressure to 10.6. But I never even needed to come close to that. What really made the difference was 

1) Increasing my min pressure to 6.8 with EPR 1
2) using AutoSet with Standard mode not "AutoSet for Her" because according to SleepHQ Nick on YouTube "AutoSet for Her" algorithm gradually ratchets up the minimum pressure and then keeps it high rather than going back down when not needed, which I believe was causing me unnecessary central apnea events.

My machine had been reporting an average pressure of 5.8 in some of my first nights when I was using pressure range from around 5 - 12, and the Sleep HQ Nick on YouTube had suggested setting the minimum pressure to around your average. By golly, he was right. 5.4 min not high enough for me to stop the OAs but 6.8 min plus EPR 1 (for functional minimum of 5.8), seems to be my number to prevent the OAs. 

With a higher minimum pressure, now my max pressure needed by the machine to stop OAs in progress was only 7.86, whereas previously even 8.4 max was not really high enough to stop an OA from forming when it started to form because my min pressure was too low.

Last night I had zero events. 
95 percentile Flow limit has dropped to 0.01
99.5 percentile flow limit to 0.08!

Interestingly, median tidal volumes didn't change much from when I had EPR off.

I am having minimal chest discomfort now using the EPR. Really relieved to have no CAs this time.

Even though I'm short on sleep overall today for other reasons, I am feeling better. I had only felt a tiny bit better since starting APAP but now I'm hopeful I'll consistently experience good sleep and be at the top of my game instead of feeling kinda tired all the time from multiple RERAs and Hypopneas if not several OAs.
I'm going to stick with these new settings for a while and see what happens.

Thanks all for your comments. Even if I didn't agree with them they helped me to scrutinize my graphs and chase down different concepts and think through what was happening better so that I could figure out my problem.

[SeePak]

groggy

glad you are on your way!

Yes, min. needed to be higher, yours was very low.
I would like to see how you got there with a few charts.

post some results so we can see your progress .

It could be very helpful for others at some time.

[lessgroggy]

I've added notes in the attached screenshots to describe my reasoning process.
   
   

[lessgroggy]

the rest of the screenshots since I'm limited to 3 per post.
   
   
   

[SeePak]

very nice, gonna need time to digest this.

One thing i will say, is that so far for me, APAP will use all the pressure i give for max. !
Possibly i really need it, not sure yet?

You may also find , in time, that certain anatomical/chemical things happen in your system and pressure will shoot up, maybe not really even necessary, causing unforeseen events.
So suggestion in WIKI is to clamp the max. to avoid this, once you know your max pressure faithfully.

Know what i mean?

[SeePak]

very impressive how you lowered the flow limits!

I have not been able to get that effect with higher pressures, though i am still <0.1 and around 0.06

I do not use EPR at this time, i may check it out in the future again.

I have been using VCOM, and it has enabled me, with higher pressures and full face mask , to get rid of almost all CA events.

That was my greatest issue, i can have >100 CA events, rapid fire in some nights.

so far so good with the new setup.

Here's link to my post about this , with a link that talks about effect of LEAKS on therapy.

https://www.apneaboard.com/forums/Thread...#pid542474

[SeePak]

@lessgroggy

Oscar WIKI pages have great info. on Therapy Optimization using APAP(which you appear to be doing well) and also on most other matters, including Flow Limitation which i include link below with highlighted area. ( good luck with the Resmed algorithm interpretation, as WIKI says " will leave your head spinning!)

https://www.apneaboard.com/wiki/index.ph...pinning%2C

Just found Optimizing page, link below

https://www.apneaboard.com/wiki/index.ph...ng_therapy