How to tell if CPAP is helping?

Yes I do have a lot of nasal congestion/cold symptoms right now! I think it's clearing up, so hopefully the next few nights will be better

DayDreamBeliever wrote: ↑

Mon Sep 05, 2022 2:21 pm

You would do well to understand what a "flow limitation" is and how it is determined. The machine manufacturer's have not made that simple and easy to understand.
At it's core the "flow limitations" that are reported are deviations from the theoretical perfect inhalation flow curve. These deviations are classed, with class 1 being the optimal inhalation curve. Unfortunately, these deviations from class one maybe caused by factors other than actual semi-obstructions in the airway.

DayDreamBeliever wrote: ↑

Mon Sep 05, 2022 1:37 pm

@Rubicon - it's a timezone thing, I'm in GMT+2. I guess sleephq could offer the option of selecting either the original or the viewer's timezone

you can adjust the time zone on your end if it’s not correct but not what others see.

Mine is always off by an hour and I think near the share option in upper right I can select change time settings or some such. It was always having me going to bed an hour earlier but I just added 3600 (seconds). If you need to go opposite way put in -3600. Give it a few to recalibrate.

hth

dataq1 wrote: ↑

Mon Sep 05, 2022 3:21 pm

Unfortunately, these deviations from class one maybe caused by factors other than actual semi-obstructions in the airway.

I discovered that today when I tried meditation breathing with my mask on after I woke up this morning. Slow breathing set off a series of pressure hikes which I was not expecting! See here https://sleephq.com/public/2f685dd0-532 ... e8c61c0b76 the last 30 mins or so.

Often if I can't fall asleep after waking up in the middle of the night I do this meditation breathing. What can I do to stop the machine going wild over it?

Any particular good source to learn more about flow limitations? Google gives me lots of academic stuff, which I'm not afraid of, but not sure what practical use it is?

lynninnj wrote: ↑

Mon Sep 05, 2022 8:00 pm

you can adjust the time zone on your end if it’s not correct but not what others see.

Thanks, I took a look at that. The times are correct for me. But when sleephq presents them to you, it uses your timezone, not mine. So I think it's a sleephq thing.

DayDreamBeliever wrote: ↑

Tue Sep 06, 2022 6:22 am

Often if I can't fall asleep after waking up in the middle of the night I do this meditation breathing. What can I do to stop the machine going wild over it?

About all you can do is limit the max pressure or change to fixed pressure.
The machine only measures air flow and doesn't have any way to know that you aren't asleep when your awake breathing appears to be flow limited for whatever reason.

See if this helps you understand Flow Limitations a bit better.
Remember they are talking about FLs in the airway itself and not in the nasal cavity where flow restrictions can be from swollen nasal mucosa.
https://www.youtube.com/watch?v=-gie2dhqP2c

http://freecpapadvice.com/sleepyhead-free-software

Also watch the videos here. While they mainly talk about flagging for central apneas/Clear Airway the premise is the same and not limited to centrals.
Our awake breathing is irregular when compared to asleep breathing and since these machines only measure air flow and they expect asleep breathing then they respond to what they sense. The machine doesn't know that your meditation breathing is what you are doing on purpose. It only knows that it isn't what it expects to sense and so it increases the pressure trying to fix what it thinks is a flow limitation problem which normally if you were asleep is what is needed to hold the airway open.

Rubicon wrote: ↑

Mon Sep 05, 2022 2:27 pm

Hi @Rubicon
I'm not sure what I should be taking away from this snapshot? I see CAs to which the machine is not responding (as it should not). These are right at the end of the capture (I think, assuming your timezone is somewhere in the USA), and I understand that CAs are common when waking up.
So how should I interpret them? Are they a cause for concern? And anyway I understand that APAP can't handle CA issues?
Thanks

@Pugsy - thanks so much, I'll check them out

DayDreamBeliever wrote: ↑

Tue Sep 06, 2022 6:46 am

I'm not sure what I should be taking away from this snapshot?

Oh right, forgot. It actually had more to do with the obstructives above in that the event-identifying pressure pulses (FOT) were not visible. AFAIK that is never suspended regardless of the pressure but was searching for that. Seems to me SleepHQ is not as flexible in getting clarity in waveforms as ResScan or Oscar.

DayDreamBeliever wrote: ↑

Mon Sep 05, 2022 2:07 pm

is it correct that flow limitations are airway restrictions on the spectrum after OA and Hypopneas? And they aren't included in the AHI number? And they are a feature of UARS?

There are some definitions involved.
Obstructive Apnea = airway completely blocked for 10 seconds with flow rate <10% of 5-minute moving average.
Hypopnea = airway partially blocked for 10 seconds with flow rate <50% of the baseline 5-minute moving average.
Flow Limitation = any condition which impairs the flow of air through the respiratory tract. So if you have the beginnings of an OA or H, but don't hit the 10 second threshold required to earn a flagged event, it remains a flow limitation. FLs are not included in the AHI number because they don't meet the definition of apnea or hypopnea.

Are FLs a feature of UARS? I don't know the answer to that.

clownbell wrote: ↑

Tue Sep 06, 2022 2:21 pm

Are FLs a feature of UARS? I don't know the answer to that.

The general consensus is that FLs don't/aren't used to indicate UARS... definitively...anyway.
If it did then we wouldn't need an in lab sleep study with the Pes device to make a definitive diagnosis of UARS.
I do know that a lot of RERAs are more likely to help out with the diagnosis than FLs being flagged would be a help.