Trying to determine lowest effective ASV settings

[Utah Desert Rat]

I could use some expert eyes on this!

I started using a ResMed AirCurve 10 ASV about three weeks ago for (according to my sleep doc) "severe central sleep apnea which is most likely a sequelae of chronic methadone use to treat Willis Ekbom syndrome". I've attached a screenshot of (what I assume is) the meat-and-potatoes part of the sleep lab report, so you can see what I'm dealing with.

The first few days were brutal; historically I've had esophageal sensitivities (probably weak valve), which made the peak pressures pretty unbearable -- to the point where I couldn't eat anymore. The sleep lab tech lowered the pressures a couple of times, which made it somewhat better. The interesting thing is that the more he lowered the pressures, the lower my AHI went. It went from averaging 2.5 to under 0.5!

Yesterday I decided to try something myself: I used the clinical settings to set the pressures to the absolute lowest the machine would go (they were pretty close to that already...). Again, last night my AHI was a spectacular 0.43 -- and I was almost completely comfortable. Being a suspicious sort, however, I'm wondering what sort of new problems those bottomed-out settings might create, so I'd love it if any of you chart gurus might take a look at last night's Oscar data and tell me if there's anything I need to be concerned with at these settings.

I omitted a couple of graphs I thought might not be useful and compressed the others a little because my laptop screen is rather small. The second screenshot shows all the machine settings.

Thanks for any input!

[SarcasticDave94]

You have the ASV pressure pared to the minimum now. And it's handcuffed. You can see by the pressure chart, it hits your Max IPAP frequently it appears. But this OSCAR chart has only 0.43 AHI. Excellent. Leak rate Max is excellent.

The only thing is flow limits, and on ASV I overlook them. You have a small amount of Hypopnea, meaning your body is signaling for higher EPAP Min. The pegging of the pressure chart means probably EPAP or PS, or both, needs increased.

Since EPAP records 4 across the board, min, median, 95%, Max, you're likely running ASV Auto mode but with EPAP Min and Max at 4.

OK what's wrong with the therapy?

I just don't see much anywhere where your settings can go lower without compromised therapy.

[Utah Desert Rat]

OK what's wrong with the therapy?

I just don't see much anywhere where your settings can go lower without compromised therapy.

From the point of view of how I feel, nothing is wrong with the therapy! I've been able to sleep quite well at the very low pressures and wake up rested for the first time in years. I can easily get used to the small amounts of pressure the machine generates at these bottomed-out settings, and going from an AHI of 38.7 centrals to 0.4 certainly seems like an excellent result all around. I'm happy with the settings, but I'm a patient. As far as I know, I could be slowly oxygen-starving myself at settings the manufacturer never thought a clinician would use!  

Would there be some medical reason you know of for raising the EPAP Min -- other than just to get rid of those last couple of hypopneas? That's the kind of thing I'm trying to find out.

[SarcasticDave94]

With this OSCAR chart, there's not a thing required to be changed at all. So data says changes aren't needed.

With your issues with higher pressure, and stating you're gaining well rested state, leave it run as is.

Done. For now, I say. Give yourself 2 weeks or at the very least 1 more week. Show us 3 standard OSCAR and tell us critically how you're doing. IF you're able to tolerate it, we can slide EPAP MIN/MAX up slightly, what I call fractionally. ResMed's like these 10's can edit pressures between whole to whole, but also with 0.2 fractional steps between. Example EPAP Max. is 4.0 now. You have 4.2, 4.4, 4.6 and 4.8 before the next whole number 5.0. See what I mean? I would have you try smallest fractional step 0.2 to your EPAP Max 4.0 and make it 4.2. Then try that 3-5 days and see if you think it's OK. Then we bump it again up 0.2. Just to get you fine tuned.

That's all I would do, is be willing to TRY it later.

[Utah Desert Rat]

I would have you try smallest fractional step 0.2 to your EPAP Max 4.0 and make it 4.2. Then try that 3-5 days and see if you think it's OK. Then we bump it again up 0.2. Just to get you fine tuned.

That's all I would do, is be willing to TRY it later.

I’m willing to try all SORTS of stuff, given how astronomically well this therapy has worked so far!
So, sure, I’ll do what you suggest. 

I’m curious, tho... (that’s the former research scientist here!), why up the EPAP max at all? 

Again, thanks for the learned responses!!

[S. Manz]

If you get a great sleep which includes deep and REM phases and your AHI is at an awesome 0.43, who cares how low  the ASV settings are. Yes you are handcuffing the capabilities of your ASV which is a bit like putting a Governor on your Corvette and set it to max out at 60mph, but if that setting provides effective therapy, I would not worry about how low it is.
My suggestion is to continue setting the minimum pressures for a few nights and then maybe try higher settings at say, 1 CMH2O at a time and see how it all goes.
In fact I will be doing the same with my ASV therapy.

[SarcasticDave94]

A reason I'd mention on increasing EPAP Max is if you encounter increased obstructions and need more EPAP power to keep the airway from closing.

[Utah Desert Rat]

Wow!! And the machine settings are the same as last posted!

This therapy has been nothing short of miraculous. I never feel like I'm at all sleep-deprived anymore, and this is unheard of, for me. Even when I get maybe 4 hours sleep (still getting used to the machine), I feel rested in the a.m. I should also note that I love my ResMed F30 mask, it fits my face very comfortably. However it does leave a couple of lines under my nose (which I don't need!), so I'm trying to figure out the Bleep. If I can make my stiff/arthritic fingers push those things together tightly enough, life will be perfect!

In answer to Dave's note about obstructions: I've never really had a problem with obstructive apneas -- very few, if ever -- so I would guess EPAP power is less important in my situation?

[SarcasticDave94]

You have to have enough EPAP to at least give you base therapy pressures. You're not gonna get better than 0 AHI. They don't issue -1.2 AHI. So if you're good with it let it be and run, build a nice little trend of sleeping well.

[SonofBiPAPuser]

I have a dumb question here.  I am just trying to learn.

I thought I read that the ASV machine doesn’t record central apneas & hypopneas, as it ramps up the pressures to eliminate them.  So if the pressure limits are set too low, I was wondering if it might not be able to ramp up pressure and eliminate, but still would not record them?  And, if so, would the reported AHI be misleading?

I guess it is theoretical in this case since Utah Desert Rat reports sleeping wonderfully and waking up well-rested.  I am just trying to learn so I understand better, in case my father ends up with an ASV machine (which I think he needs).