Morbius wrote: ↑Thu Feb 24, 2022 8:12 am
So let me ask you something.....
I'm not sure to whom you are addressing your question.
But as the person who initiated this thread I'll respond for myself.
For the past 21 years I have been using Phillips Respironics Apap machines. Late last year I was introduced to the Resmed Autoset. In the past I've used Sleepyhead, and more recently Oscar.
Comparing reports, (Sleepyhead/Oscar on the Dreamstation (and it's predecessors) with Resmed Autoset 11 on Oscar, was a Resmed function that I had never seen before entitled "Flow Limitations".
At least for my reports, it was clear that the Resmed machine reacted to changes in this quantified or graded changes in the evaluation of 0-1.0 of Flow Limitations.
What I initially thought was odd was that there seemed to be no analogous (flow limitation) evaluation of the flowrate-time curve on either past or present Respironics devices.
When I inquired on this forum about Resmed's algorithm to evaluate and grade this flowrate-time behaviour on a 0-1 scale, IIRC the response was something like, Resmed doesn't really explain (except in very broad terms in their patent disclosures) how they arrive at grading, and specifically how they might arrive at a grade scale of 0-1 (least to most severe)
Another response was that flow limitations (and it's subsequent grading) was somehow similar to breathing through a straw. However the problem with that explanation was that breathing through a straw (it seemed to me) would impact the effort required to inhale
and exhale somewhat equally, but would not necessarily impact the morphology of inhalation/exhalation curves. (for clarity sake, by morphology I'm referring to the shape, rather that the amplitude. But it seems one of the basis for Resmed's establishing a "grade" for flow limitation is actually distortion of the ideal (parabolic) inhalation curve.
That's what initiated this discussion (for me):
1) Seeking a better understanding of what Resmed calls a flow limitation and,
2) As Resmed considers the characterization of the flowrate-time curve to be vital in continuously adjusting pressures, why would Respironics (seemingly) ignore that characterization.