[Treatment] ASV settings for treatment of complex sleep apnea

[JoeyWallaby]

Thank you.

[jaswilliams]

I agree with the others I see nothing else to change for now is the ASV beneficial ? How do you feel ?

[JoeyWallaby]

Feeling better than I was on any of the other machines, more energy during the day, actually starting to feel refreshed in the morning 

I'm surprised I can tolerate such a high PS when I'm asleep, well, I guess it makes sense... since the pressure increases would really only be compensating for a more collapsed/narrowed airway or to treat CAs.

[slowriter]

I realize it's still early to draw strong conclusions, but what do you think has changed in the objective data that would explain better subjective outcomes?

I was looking back at your earlier thread, and I wasn't seeing the problem in your wave forms, etc.

I've read a lot of Krakow's stuff advocating ASV for treating UARS, but I never exactly understood why, or under what conditions it makes sense, so I'm partially using your specific case to try to figure this out.

I also suspect someone like me would not benefit from ASV, so I want to understand that as well.

[Geer1]

I've read a lot of Krakow's stuff advocating ASV for treating UARS, but I never exactly understood why, or under what conditions it makes sense, so I'm partially using your specific case to try to figure this out.

The problem in UARS is the arousals. The arousals at least in some theories are caused by a slow steady increase in CO2 due to continuous minor flow limitation which makes sense to me. As the analogy goes it is like breathing through a straw and if you try that it may take a while but eventually you start to feel the effects.

ASV differs from APAP and bilevel in that it compensates flow limitations in order to maintain a minimum minute vent. You can see that in JoeyWallaby's results where it supplies enough extra pressure to not only bring his breathing back to the same rate prior to the flow limitation but to actually influence a larger breath/breaths to make up for the flow limited breath. This would at least in theory provide some advantages for UARS. 

I imagine the right EPAP and PS settings with auto bilevel are effective for lots of people with RERA issues but I could see ASV being advantageous in more difficult situations(especially if flow limitations fluctuate like say are obviously worse during rem sleep).

[JoeyWallaby]

Which waveforms are you referring to, when you say you can't see any problems in them? In my old thread, if look at the CPAP charts with anything from EPR off to EPR 3, you can see my breathing is clearly flow limited. While it isn't severe, more like mild-moderate, you can see a massive improvement in moving to BiLevel. The problem was that with BiLevel, I was having significant CAs despite everything I tried, so moving to ASV has treated the flow limitation and also the CA 

CPAP flow limitation
http://www.apneaboard.com/forums/Thread-...#pid320050

BiLevel CAs
http://www.apneaboard.com/forums/Thread-...#pid323577

[slowriter]

Yes, I was referring to on the bilevel.

So bilevel did, in your view, treat the FL, and you moved to ASV because of the CAs?

[JoeyWallaby]

Correct.

[slowriter]

So to answer my own question, we might say, as a general rule, ASV may be worth trying for those with substantial FL-induced arousals (UARS, etc.), and who either:

1. suffer from treatment-emergent central apnea, even at standard bilevel PS ranges (4-6), or
   
2. require very high (greater than 6) and/or variable PS that would otherwise almost inevitably lead to central apneas
   

[sheepless]

tangentially related, for the sake of discussion, I'll add that asv brought my ahi down to about 0.3 but wasn't able to compensate for my non-passive periodic leg movement induced flow limitations. pressure support can't be limited enough to avoid rapidly swinging ps; I didn't realize until trying vauto how much it was disturbing me, even though I was unaware of it. currently running vauto with ps 5 ps and with relatively low ipap to avoid the beating I was taking with asv. result is higher ahi (still under about 3) but feeling better than ever in 3 years of pap'n.

however, I will say that if the results are accurate, the efficacy of the asv to get the lowest possible ahi can't be denied.