(03-19-2015, 01:10 PM)eseedhouse Wrote:
(03-18-2015, 08:36 PM)TyroneShoes Wrote: Technically he is right because APAPs raise pressure based on an event (OA, FL) or series of events. So yes, it does not prevent the original event when pressure had not been yet raised
I don't think this is correct, at least in the case of my ResMed machine. It also keeps track of flow limitations and raises pressure in response to them. Thus the pressure is likely to start going up well before any actual apnea event.
Well, I think you are right, but I think we are both right, because that is very close to what I actually said, in context. My Autoset acts (REacts
in response, actually) probably in the exact same manner as yours does, something I am quite familiar with. You might have noticed that I mentioned FL as an example directly in my post, which you quoted. And maybe you did not notice that, or some other things that I also covered.
But APAP does not raise pressure to prevent a FL; it raises pressure reactively
to a FL. And just like how it reacts to a OA event, it does nothing about that event other than REACT to it by changing pressure after the fact
to help the odds of preventing successive events.
I am defining "event" here as anything not kosher with the regular, normal pattern of healthy respiration, and not just restricting it to OA/CA/H events that are long enough or severe enough to be flaggable. So a FL is an event also, if you follow that logic, even though it is not flagged as an apnea. I am also including "undefined" apneas as well as the user-flagged events from SleepyHead, also events that APAP might REACT to.
APAP does not have a crystal ball, and can't predict actual events and fix them directly, only raise pressure in response to them in hopes of preventing future events that it also can't predict
. By the time an OA event is long enough to be recognized as such and flagged accordingly, it is essentially already over. The boat has sailed. Without a time machine function, no xPAP technology can go back and prevent an event, because it does not know about it until it is over, and you can only REACT to something that is over. PROactivity is not an option.
So APAP is indeed reactive (doc's correct about that), as well as preventative (doc's incorrect about that), but only preventative regarding successive events. The term you used above, "in response" refers to a reactive process, by definition.