ASV producing elevated AHI

[JustHitSnooze]

First time new member but longtime user admirer of Apnea Board. 
As an RPsgT and former RT of course I’m titrating myself because sleep studies cost too much to get a one time shot to get my pressure right. 
Why is my AHI steadily increasing while on fixed epap on ASV. My AHI is higher than my initial diagnosis but unfortunately AirView doesn’t show centrals if using ASV. 
Epap at 4.4cmH2O PS 0-5 using F40 ffm with 1lpm leak, AHI hovers between 8-13.
When I set epap to 4.2 AHI hovers around 6. 
Tried using AutoASV set epap 4-5, PS 0-5 but AHI jumped to 18-21. 
Ahi from sleep study was 11. Majority were centrals with only 2 obstructive. 
Any ideas as to why the increasing AHI whenever the set epap is higher. What should I try to adjust?

[Jay51]

Welcome to ApneaBoard.  Visit us when you can.  

I have an S9 Adapt ASV (single, static EPAP setting), and have tried most of the ventilators on the market currently.

I can't explain your situation.  The only possibly thing could be that with the 4-5 EPAP range, when it drops down to 4.0, that is when problems are occurring.  It takes some time to get back to 4.2 and above after it bottoms out at 4.0

From my experience, using a soft cervical collar with my ASV (and OSCAR's) reduced my AHI.  

4.2 seems to be the best results, so if me, I would stick with that.  No idea why your AHI jumps when you go up to 4.4 EPAP.  Do you even have any guesses on this?

Some members here are experts with ASV.  Some members have looked at thousands of OSCAR charts also.  So you might get the answer that you are looking for here.

[JustHitSnooze]

Thanks for the cervical collar tip. I’ve been trying pillow tricks to hold my chin up but not thrust my head too far back. It’s been hit or miss. 
Can’t explain the increasing AHI as I use higher epap settings. I’ve tried using Airsense 11 AutoCpap 4-15 no epr but my pressure kept maxing out at 15. Changed to 4-18 and pressure average was maxed out again. One significant increase was CAI was 16. Evidently I gave myself more central apnea. 
Switched to Aircurve 11 VAuto with worse results. 
The pressures maxing out concerned me as I am 5’-9” and 135 soaking wet. 
With the ASV epap at 4.2 and PS 0-5 my inspiration is averaging 8. 
According to the manufacturers experts that I spoke with who helped design the algorithm, Airview doesn’t show central apnea index because you shouldn’t have any while on ASV. That struck me kinda funny. Although rare to see a perfect zero for any events, I have seen it on some of my patients that I service. 
Getting Oscar is a whole other thread for this guy. Old MacBook. Nuff said!

[SarcasticDave94]

You'll want OSCAR, our free report tool to work on your computer. With OSCAR and loading sleep data that's on the SD card put into the ASV the night before, we then can see what's going on.

It's likely your pressure set is too low. I myself when on ASV from 2017-'19 I almost always used ASV Auto mode, EPAP 7-12, PS 3-15, giving IPAP 10-27. Averaged 0-3 AHI most of those 2 years.

You'll notice you can edit EPAP and PS, but not directly with IPAP, but manipulating the first 2 will indirectly change IPAP as EPAP plus PS equals IPAP.

With edits and seeing OSCAR data to assist it can become better than this.

[JustHitSnooze]

Thanks for the breakdown. I was an avid user of Sleepyhead but I hate buying new computers. With iOS 10.10 I can’t get Oscar to work. Time to face the fact that Apple wants me to buy more stuff. 
Just curious though, you said you were on an ASV for what looked like 2 years or so. 
May I ask why the switch to the VAuto? About 80% of my sleep study events were centrals. 
And if you happen to know where to get an older version of Oscar for iOS 10.10 (highest update capable) I’d love to load my SD card data. At least until I decide on a hand me down computer from my kids.

[SarcasticDave94]

I was using ASV, doing well... But COPD/Asthma got in the way of the ASV causing breath sync to skew. And ResMed ASV has auto timing controls only, no manual settings for this. I was told by the current of that time RT to get a ventilator, but doc didn't agree.

July 2019, I had pneumonia with some lung scarring, then in September 2019 bout of bronchitis, both contributed to ASV no longer working with me.

New sleep study plus PFT (pulmonary function test showed minimal COPD negative effect, hence no ventilator, despite still being listed as COPD GOLD 3.

Trying VAuto to see what it does after being off therapy 4 years and poor sleep.

[JustHitSnooze]

Have you heard of the AVAPS? Non-invasive hybrid ventilation where you set a target final volume and it addresses the osa component by adjusting expiratory pressures. Supposed to help with hypoventilation caused by neuromuscular disease. 
I’ve only played with this technology once. It’s pretty similar to a trilogy I think.

[SarcasticDave94]

Yep, definitely. That's what I'm actually trying to get, AVAPS that is.

ResMed ST-A that's the same footprint as VAuto, AutoSet, ASV, has ResMed's version of AVAPS called iVAPS. As does the full vent Astral.

I've borrowed an ST-A from someone a while ago and it worked well. It might have been an earlier ResMed 10 series because EPAP was static. I think newer ST-A has added an EPAP range much like ASV Auto. Anyway the ST-A has the full complement of Auto and manual timing controls.