BrianinTN wrote:justinjustin wrote:I have ComplexSA / UARS, but the xPAP doesn't help and in fact makes things worse. It's so counterintuitive, especially when I've spent years controlling for other factors like sleep patterns, hormones, etc, etc, etc,
I should clarify that ASV performs like a champ by the numbers.
The sleep patterns and hygiene part is a real chicken-and-egg game here. I can't get any good habits going while on the ASV. And I'm having my sleep disturbed by a sea of hypopneas when I'm not on xPAP. So unless I can figure out some way to reconcile the two, I'm going to be a long-term non-complier. And that sucks...but it's also why I
desperately would like some theory on why I feel worse on ASV/BiPAP/CPAP than when I don't. I feel like an answer to that might at least start pointing me toward a solution.
OK, speech over. /gets off soap box
I hear you, my AHI is 0.2 - 2 on ASV. But here's something *very* interesting I found on another board:
http://www.apneaboard.com/forums/Thread ... ion?page=3
Perhaps the algorithm is causing you arousals and it needs to be less aggressive? The explanation below makes a lot of sense to me in my own case at least as I used Resmed S9, although I see you're on PR....
"Resmed's algorithm is far more aggressive than the PR algorithm in treating FLs. And that can contribute to some people complaining that the AutoSet has a tendency to have the pressure "run away."
Quote:
I'm pretty sure that ResMed sees these patterns as being disruptive to sleep even in the absence of what would technically be called events.
Yes, there is some evidence that FL can be disruptive to some people's sleep. In fact the whole problem that folks with UARS have is that the flow limitations tend to trigger EEG arousals well before a clinical H can be scored.
And so it's all well and good to try to eliminate the FL. But---and this is an important but: Some people find those rather rapid and significant increases in pressure more disturbing to their sleep than the FL themselves. Sharp increases in pressure can and do wake some people up. And if you're prone to aerophagia all that extra pressure to eliminate the last of the FL can increase the aerophagia, which can increase the arousals, and lead to even more swallowing. Sharp significant increases in pressure can also lead to additional problems with mask leaks and also under some circumstances trigger mouth breathing in a person who otherwise breathes exclusively through their nose. And those things can cause problems with both the quality of the therapy and the quality of the sleep. And finally there's the fact that about 10% of PAPers do have some problems with pressure induced centrals.
So when a CPAP maker is designing an auto algorithm, how they decide to respond to FL is almost by definition a series of compromises. You want to increase the pressure (at least some) and see if that helps stabilize the shape of the inhalations, but you don't want the pressure increase to be so rapid and so great as to cause as many problems as it solves for the vast majority of users.
I think that's part of why PR has taken a very different route in dealing with FL. The PR machines do respond to FL by increasing the pressure by 1 cm and then they wait for about a minute, if I recall correctly. If the breathing stabilizes in that minute, there's no further increase. If more FL are detected, the machine raises the pressure another 1cm and waits another minute. It's slower to respond, but that means the pressure increase by itself is less likely to wake up or arouse the user. And PR also attempts to proactively find the best pressure even before the inhalations in the wave flow have become ragged enough to trigger a FL flag. And that proactive "search" algorithm also prevents the PR System One from lowering the pressure too far, too quickly."