Need Help with ASV Settings

What is the difference between flow rate vs flow limit? I'm new to interpreting sleep data. I only looked at AHI in the past. Does sleep limit data tell me anything of value or is it just data for data's sake? I'm struggling with mask leaks at the moment and notice a correlation between the leaks and the high flow limit number (1.00).

Underdog wrote: ↑

Sat Nov 15, 2025 9:21 pm

What is the difference between flow rate vs flow limit?

1. This question and some of your other questions were answered in your post from 20 months ago ( viewtopic/t187994/Help-for-the-clueless ... YwJGwwJGgw ). It's a good idea to reread that post.

2. It's good that you know how to use OSCAR, but please use SleepHQ for discussions here. You have used it in the past. It allows members to zoom in on your charts.

3. Which mask are you using? Have you found your model on YouTube and watched two or three videos on fitting and adjusting?

4. Are you tossing and turning often?

5. What was your original diagnosis? Did you ever ask why the doctor prescribed an ASV machine?

Thanks.. This old post was helpful. I will reset from baseline and go from there. Not sure what mask I have. Is there a model number printed on it? I have continued to gain weight. With CPAP my AHI was higher, and I had difficulty adjusting (felt like an inflated balloon). I'm hoping the ASV will be a better experience. So far, so good, but time will tell.

Here is my recent ASV experence:
https://sleephq.com/public/3c65e9c4-61a ... 4980a31d91

Here was my recent CPAP experience that seemed less favorable:
https://sleephq.com/public/a3b4a026-863 ... 20d6054db9

Re: Help for the clueless
Post by Respirator99 » Fri Mar 15, 2024 12:45 am

Obviously the leaks are the main concern right now, and other factors really only come into play once the leaks are under control.

You can ignore the flow limitations - Resmed ASV machines report limitations differently from other types. From the Apnea Board wiki:

Flow limitation is a common characteristic of pressure support induced inspiration. When you don't make the spontaneous effort to breathe, the ASV pressure support does ensure a volume of air is inspired; however as the lung fills, resistance increases, and this gives the appearance of flow limitation. This is not upper airway resistance, but a function of resistance in the lung itself. We see this on nearly every individual that has posted close-ups of the respiratory flow wave during ASV and ST non-invasive ventilation intervention. We don't try to treat this form of flow limitation, but rather accept that it is a common result of non-invasive ventilation.


Assuming your central apnea was in fact bad enough to warrant an ASV, then your settings are a long way off what is normally regarded as optimal. For a start, you're not making use of the ASVAuto mode. Secondly, Resmed recommend that PSmax be not less than 15 (you have 10). Once your leaks are sorted, I'd suggest the following settings to establish a new baseline, and adjust from there:

Min epap 7.0
Max epap 15.0

Ps min 3.0
Ps max 15.0

Min ipap 10.0
Max ipap 30.0

Underdog wrote: ↑

Sun Nov 16, 2025 3:46 pm

Not sure what mask I have. Is there a model number printed on it?

you can check here and see which mask you have-
https://www.cpap.com/
then see the pull down menu for CPAP masks.

Underdog wrote: ↑

Sun Nov 16, 2025 3:46 pm

Here is my recent ASV experence:
https://sleephq.com/public/3c65e9c4-61a ... 4980a31d91

Scroll to the top of this thread and click on the Edit icon (pencil). Change the subject line to "Need Help with ASV Settings".

Big help. This mask is a Phillips Respironic Comfort Gel Blue (large).
My leaks are near my eyes, and I can push on the mask and stop the leaks. However, tightening the straps to stop the leak results in too much painful pressure on the top bridge of my nose and forehead. A larger-sized head, but a narrow beak-like face, and a larger, narrower nose.

I found this guidance on YouTube
https://www.youtube.com/watch?v=v4Sgqn9eZaE

Here are the results with ASV "auto" reset to baseline:
Personally, I would prefer less air volume. I tried a few adjustments to the mask, but the leaks seem about the same. I may order a new gel and see if that helps.
https://sleephq.com/public/2534991a-659 ... 94a337d2b4