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Flow Limitation Index
#1
Its my understanding that APAPs respond to flow limitations by increasing pressure, but why do APAPs score a flow limitation index?  I'm curious as to what is an acceptable or good flow limitation index and what might be considered unacceptable or poor.  In other words, what is considered high or what is considered low?  I have observed that on some nights I'll have a positive FL index and a RERA index of 0.  Then on other nights, I'll have a FL index of 0, but a positive RERA index.  Can my machine confuse the two?
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#2
In general, this is the sequence of events as the airway closes more and more.

All good->Snore->Flow Limitation->RERA->Hypopnea->obstructive Apnea

The machine has algorithms to look at your breathing waveform and slot it in these buckets. So it's not rare to see it slot some RERA but no FL.

A FL event in itself will not disturb your sleep architecture or reduce your spo2. I won't worry about them. The APAP algorithm does take it into account and proactively raise pressure to 'stay ahead' of any AHI event that may be coming down the waveform. Resmed raises it more aggressively than respironics.
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#3
(03-08-2017, 01:31 AM)AshSF Wrote: All good->Snore->Flow Limitation->RERA->Hypopnea->obstructive Apnea

Thanks for the flow chart (pardon the pun). That really makes sense when you put it in writing. Have been wondering the relationship of Snore/Flow Limitation/RERA.
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#4
(03-08-2017, 01:31 AM)AshSF Wrote: ->Snore->Flow Limitation->RERA->Hypopnea->obstructive Apnea

Do all of those count toward AHI?  Such that AHI is the avg of the sum of each of those per hour?

So what we're trying to do, via xPAP, is to decrease as many of those as possible?  If we can't get rid of all of those, is it best to decrease the more severe ones (ie: OAs) and let some of the less severe (ie: snore, FL) stick aroune?

Where does a CA land in that "flow" (haha)?  Or is it a thing of its own, since it's a brain thing rather than a physical obstruction?
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#5
A link from the Beginners Guide to SH explains in depth the relationship of flow limitations,
Rera's and apnea, and how they are scored.

http://www.apneaboard.com/wiki/index.php...Rate_graph
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