Flow Rate Pattern Question

[crazybuffalo]

Hi. I've had what I think is relative success since I started CPAP in 2017, especially after I turned off APAP and am using CPAP. Of course I see things as I look at my Oscar data that Resmed doesn't catch which are probably events, but even so they are relatively few in number. 

I think it's working for me, but I don't know what I don't know.  That said, I've never been able to work out why my flow rate looks like it does, and what the implications of it are. The VA techs all have only looked at the AHI and that's about it and don't care about anything else (other than my comfort, and they have been very good about getting me a mask that allows that).  Right now I'm using what is by far the most comfortable setup I've ever used, which is the F&P Nova Micro, sometimes mouth taped, sometimes not.

The zoomed-in pattern in the screenshot (from last night) has been consistent since I started using CPAP in 2017.  Specifically, I'm referring to (a) the flatness on the center line, right before the rise, and (b) the flattish top. 

I've had the impression from research that the flattish top (b) is an obstruction. I tried increasing the pressure from 9 to 11 and it hasn't changed the flattness one bit. Should I go higher?

As for (a), I have no idea what it means.

Any help interpreting these is welcomed.

[jdougc]

Those are flow limitations, you need to use EPR to deal with them.
[attachment=78494]

Try EPR or 2 or 3 and see how you feel.
Your ramp is too low for an adult, it need to be at least 7cm, maybe a bit higher with EPR turned on.
You may experience CAs when using EPR, but they should diminish over time.

[crazybuffalo]

Thanks, I'll try that. A question though: if there were flow limitations, wouldn't those show up on the "flow limit" graph? I went through a few nights worth of charts where the flow rate pattern matched, but saw very few if any flow limitations, and those that did appear resulted in very obvious flow rate differences and OAs and Hs. 

Last time I had EPR set, I ended up with some nasty headaches in the morning, but i can't directly associate the headaches with EPR...would an incorrect EPR setting cause CO2 issues leading to headaches?

Thanks again for your input.

[jdougc]

Any changes take time for our bodies to get used to.
Using EPR can lead to increased CAs for a time, which should diminish.

I had to increase my pressure when I used EPR as ResMed doesn't recover very fast from exhalation when using EPR, maybe that is why you had a headache?
ResMed is terrible at scoring low limitations, as you saw when you scrolled through your flow rate chart.

Finally, I have to ask, are you sleeping well?
If the answer is yes then ignore anything I commented and enjoy your success!
Many people sleep right through these flow limitations.

[crazybuffalo]

Thanks for the insight.

Re sleeping well: I guess?? That's why I said "I don't know what I don't know" in my first post. At times I feel rested in the morning, sometimes I don't. At times I feel sleepy in the afternoon, at times I don't. I mostly seem to fall asleep within 5 minutes of bed, except when I don't. I often wake up at around 3am, and sometimes I fall back asleep right away and sometimes I'm up for the day.

What I can say for certain is that if I don't wear the mask I ALWAYS wake myself up choking, particularly early in the night. I also know my AHIs went down when I went from APAP to CPAP and I did feel better overall. So I know it's doing something beneficial, but I always wonder (given the paragraph just prior): is it doing the best it can?


I'll change the pressure to 13 and start with EPR of 2, and go from there.