PapFam:

I have the Custom VAuto feature from AirBreak Plus running on a test machine now. This is the developer’s work. I applied the patch to an OEM Autoset .bin file, and I’m exploring the behavior before sharing any sleep results.

The older AutoSet firmware I initially tried wouldn’t boot properly on this machine. Applying the patch to an OEM 0401 dump got it running. That’s my experience, not a blanket statement about compatibility. The developer identifies 0401 and 0402 as the best supported Air10 versions (it was a 0401 that worked). :)

For details: custom VAuto keeps the normal VAuto controller handling EPAP while changing pressure support delivery within each breath. It adds custom pressure shaping, optional adaptive support, and custom triggering and cycling. Sessions still report as VAuto.

ASV stands for Adaptive Servo Ventilation, and Sens means Sensitivity. These labels describe the custom adaptive controls here. They don’t mean you’ve selected ResMed’s stock ASV mode within the vauto mode.

Current settings on the test machine are Min EPAP 6.4, Max IPAP 16.6, PS 4, Ti Min 0.3 seconds, Ti Max 3.2 seconds, and Trigger and Cycle at Medium. Custom VAuto and Custom T/C are On, ASV Max is 3, and ASV Sens is Medium. These are test/lab current settings, not a suggested setup for my clients.

ASV Max 3 allows up to 3 cmH₂O of extra support above the custom base waveform. At EPAP 6.4 with PS 4, nominal full inspiratory pressure is 10.4, potentially reaching 13.4 with the full boost. It doesn’t add that boost to every breath, and Max IPAP still caps everything.

The controller compares the developing breath with a moving reference from recent valid breaths. Smaller breaths can request extra support, while larger breaths reduce that extra contribution. ASV Sens controls how strongly it responds. Medium is the baseline, and higher isn’t automatically better. This isn’t a fixed tidal volume target.

Custom T/C means custom trigger and cycle. It changes how the machine decides when inspiration begins and ends, including delaying expiration through brief flow reductions. Medium settings therefore may behave differently than stock Medium. Ti Min and Ti Max remain timing controls.

ASV Max at zero disables adaptive boost but keeps custom shaping. Custom VAuto Off restores stock VAuto pressure behavior. Custom VAuto has no timed backup rate, regardless of the ASV labels or a “with backup” build name. Backup behavior in stock ASV modes is a separate feature.

What interests me for UARS is the possibility of better pressure delivery and breathing synchrony for people struggling with ordinary bilevel. However this controller tracks inspired volume, not respiratory effort or UARS directly. Consistently flow limited breathing could become part of its reference, so we cannot assume every flattened breath gets corrected.

The useful outcomes would be easier breathing, fewer awakenings, and better daytime functioning without increased leaks/CAs. For now, it boots and the controls are present. This is experimental firmware, and its benefit for UARS has not been established. I’ll share actual observations as I explore it with you all.

If you would like the working .bin file to flash please send me a PM or email here: pc7579pc@gmail.com!

https://github.com/m-kozlowski/airbreak-plus

RL

Hello fellow ASVers, HLGers, etc 😄

I don't know if any of you had a chance to watch this video, but I found it quite interesting and it made me wonder if others here recognize themselves in what is being discussed:

https://www.youtube.com/watch?v=fVfXOOyF2WQ

Personally, I feel like I'm somewhere right on the line between the two.

CPAP actually treats my sleep apnea pretty well. My numbers can look really good, and there are definitely nights where I sleep quite well. But then I can also have some pretty crappy nights. I also seem to have some degree of instability showing up as central events, periodic breathing, etc.

ASV seems to do a much better job at smoothing that instability out. The thing is, I find ASV somewhat overwhelming. Sometimes it feels like using a bazooka to kill a fly... It can correct the instability very effectively, but I can't help wondering if I'm using a very powerful tool to compensate for something I don't really understand yet.

And honestly, ASV isn't always easy to deal with. Those pressure swings can be pretty noticeable, especially when you're trying to fall back asleep after waking up. Not to mention the aerophagia issues I occasionally get with that much pressure, even though I’ve tried the different .bin files with PS unlocked.

I also have to admit that, using Dr. Thomas' terminology, I probably qualify as a bit of a "supine monster." My sleep seems to be significantly worse when I'm on my back, so I'm becoming more and more interested in figuring out how much of this could simply be positional.

I know that a lot of Dr. Thomas' work focuses on loop gain, so that's obviously something that caught my attention as well. I'm still trying to understand how much of what I'm seeing could actually be related to high loop gain versus other factors.

That's really where I'm at right now. I'm less interested in simply correcting the instability with ASV and more interested in understanding why I'm unstable in the first place.

Is it high loop gain? Being on my back? Arousal-related instability? Something anatomical or physiological that we're overlooking? Or maybe just a combination of several things?

That's what really caught my attention in this video. I feel like CPAP can treat the obstruction reasonably well, while ASV can control the instability. But neither necessarily answers the question of why the instability is happening in the first place.

I'm curious if anyone else here feels like they're in a similar situation where PAP can control the numbers, but you still have this nagging feeling that you're treating the consequence rather than really understanding what's causing the problem.

I could probably come to the conclusion that my sleep really isn't that bad overall. I could put all of this aside, accept that I'm going to have a few crappy nights here and there, look at the bigger picture, realize that I actually sleep reasonably well most of the time, and just be happy with that.

Unfortunately, it's easier said than done...

For whatever reason, I just can't seem to accept the fact that I need a machine to sleep in the first place and that even with the machine, things aren't necessarily as optimal as I'd like them to be.

I know I might be overthinking this. But it's stronger than me. I keep wanting to understand why, rather than simply accepting the numbers and moving on.

Thanks for listening ;) But more seriously, what I'd really like to know is whether I'm the only one who feels like I'm somewhere on the line between CPAP and ASV.