Flow limitation questions (ResMed S9 Autoset)

kaiasgram wrote:Thanks so much for these examples. Thanks to both you and Pugsy. I generally have a pretty ugly-looking waveform even though I have very few OSAs or Hypops -- very few. But I might be skating the edge of events and/or having RERAs that continue to affect my sleep. Trying not to be obsessive but since our S9's don't flag RERAs or FL 'events' for us, I'm wanting to look a little more closely at whatever clues those graphs might hold to see if I could tweak my pressures or EPR a bit more and improve my therapy. Thanks again guys.

Improving the therapy is the reason for the season. If you have a hard time seeing the "chair" in your waveforms, take a small swig of dark rum, wait about 5 minutes then squint your eyes and it'll jump right out at you. The sleep tech that last wired me up for my titration study was all over me about the wonderful medicinal properties of marijuana, once he found out I work in pharmacuetical R&D. I was wondering why his eyes were bloodshot. He said he had been surfing all day, but he wasn't sunburned. So I suppose some sort of chemical assistance helps them to tweeze the signal out of their data.

Dragging up an old thread, because it's related to what I'm asking...

Has anyone observed a flow limitation peak of over or even close to 1.0?

Would S9 users benefit from Flow limitation peaks to be flagged as events in SleepyHead?

The S9 can have these events flagged basically the same way Vibratory Snore flags are generated from the snore graph on PR System One. (By marking flags when a peak cross a certain threshold)

On that matter, it can easily have Vibratory Snore flags too if you enough of you want it.

jedimark wrote:Has anyone observed a flow limitation peak of over or even close to 1.0?

Sure:

jedimark wrote:Would S9 users benefit from Flow limitation peaks to be flagged as events in SleepyHead?

Well, "IMHO", I would say no, because interpretation is based on looking at the overall trend.

TS, if you wanted to identify discrete events with FL properties, that might be added in addition to the trend line. These discrete events would be the equivalent of RERAs seen in in other algorithms (of course, you would also need to add start, and more important, stop criteria for the RERA).

TS2, 1.0 is useful to identify/discount artifact. IOWs, if say the upper limit was 0.4, artifact would have the same value/significance of clinically relevant FL (at least visually).

mollete wrote: Well, "IMHO", I would say no, because interpretation is based on looking at the overall trend.

TS, if you wanted to identify discrete events with FL properties, that might be added in addition to the trend line. These discrete events would be the equivalent of RERAs seen in in other algorithms (of course, you would also need to add start, and more important, stop criteria for the RERA).

TS2, 1.0 may be useful to identify/discount artifact. IOWs, if say the upper limit was 0.4, artifact would have the same value/significance of clinically relevant FL (at least visually).

I'm not suggesting removing the graph, it's very useful on it's own, but adding flags as a complement to show in the overlays over the flow waveform.

From what I understand, RERA is basically any period of sub-hypopnea "respiratory effort" that is accompanied by awakening, or at least a disturbance of sleep... which aren't really flag-able on any of our machines without reasonably reliable sleep staging data-source (meaning PRS1 RERA events are slightly bogus, at least according to the definition). Where a Flow Limitation is a dampening of flow waveform peak, showing a marked reduction in tidal volume compared with a running average.. ?

Significant Flow Limitation events could be flagged like periods of Periodic breathing on the PRS1, showing a span of when the marked condition starts/stop?