Tidal volume and Flow limitations

[Morbius]

And the FL channel is probably wrong too. Although since it's just a summary of a bunch of things I guess that's academic. "Something significant is happening there" is all you need to know.

[AmSleepnBetta]

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Cause it looks to me like the little stutter prior to inhalation is contaminating true I-time.

Did not notice that. A good eye and fair point, seeing the cursor is on a cardio peak. Fortunately, the view shows much wider divergence later driving I/E higher so my main point there survives overall.
I don't recall just now whether there was a reason to select that particular time--doubt it. Probably just accepted the location I landed on for the example. I got the cursor location's I and E read out as shown
in boxes at left. Those readings for cursor location cursor have always checked out.

[AmSleepnBetta]

. . .. Cause if I understand you correctly (although reread above) in the area where you identify conflict duty cycle actually remains constant, and all you got is a guy breathing slowly and deeply, as you might find in SWS.

Yes, for many with UARS and such, "breathing slowly and deeply between arousals".

It looks to me like I: and E:time are also presented as a 5-breath moving average, so now you've got the same problem (or worse) that you have with tidal volume.

Yep, those blasted averages, a time to love them and a time to hate them. To get breath by breath TV, I and E values I have integrated flow rate data to get rough TVs, then filtered almost all the cardio out as mini-breaths (forget the value now, about 0.025 L, I think) and then taken the filtered TV start and end times for I and E times . 'Did that some. But need to resume my abandoned intial interpolations once done to find zero-axis crossing points for data (few data hit the axis).TV is not sensitive to that, but I and E time is and results without interpolation have been useful but far more spikey than seen in I and E now.

Oh, by the way, I had read the report and shared (last September?) those two excellent "among and within" graphs of waves you posted. I had seen the other batch of curves too, but thanks for thinking of me.

Yes, I think it is "Starling" but in my post I just stuck collapse on the end (to deal with the diminishing flow extreme.

[Morbius]

Cause if I understand you correctly (although reread above) in the area where you identify conflict duty cycle actually remains constant, and all you got is a guy breathing slowly and deeply, as you might find in SWS.

Yes, for many with UARS and such, "breathing slowly and deeply between arousals".

No.

[Morbius]

Oh, by the way, I had read the report and shared (last September?) those two excellent "among and within" graphs of waves you posted. I had seen the other batch of curves too, but thanks for thinking of me.

Yeah but when you posted

Real NED is when an increase in muscular efforts to draw an inspiration will not increase airflow into lungs.

I knew you didn't understand it.

[Morbius]

Yes, I think it is "Starling" but ...

Probably still don't.

[Morbius]

So let me ask you something.

What do you intend to do with this massive influx of new information?

Bring it back to the other place to impress your little friends?

Those pesky inquiring minds again!

[dataq1]

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.

[palerider]

breathing through a straw (it seemed to me) would impact the effort required to inhale and exhale somewhat equally,

Why ever would you think a ridiculous thing like that?

Oh, hah, sorry, I expected you to think, sorry, my bad.

[Morbius]

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.

Well I must apologize, I thought I covered every point in this discussion. Sorry I missed this.

TTBOMK Respironics considers the characterization of the flowrate-time curve to be exactly as vital as ResMed does in continuously adjusting (although I would say "monitoring") pressures.

[Morbius]

in continuously adjusting (although I would say "monitoring") pressures.

Or maybe "selectively adjusting".

[Morbius]

Or maybe "selectively adjusting".

Cause just because it sees a change in a FL criterion it doesn't mean it's going to necessarily send the pressure through the roof.

[Pugsy]

Respironics machines only flag FLs in auto adjusting pressure modes and they flag them like they would an apnea event up on the events graph...BUT ONLY IF the mode is auto adjusting.

In fixed mode the Respironics machines don't record FLs at all. Doesn't mean they didn't happen....just means they didn't get recorded or flagged. Don't know why Respironics decided that FLs weren't worth reporting in fixed mode unless maybe since in fixed mode the pressure can't change so the FLs weren't worth flagging. That's a question you would have to take up with Respironics.

If you never saw FL flagged on your Respironics machine's SleepyHead/OSCAR reports perhaps you were using the machine in fixed pressure mode?????

dataq1 wrote: ↑

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.

[Morbius]

In fixed mode the Respironics machines don't record FLs at all. Doesn't mean they didn't happen....just means they didn't get recorded or flagged. Don't know why Respironics decided that FLs weren't worth reporting in fixed mode unless maybe since in fixed mode the pressure can't change so the FLs weren't worth flagging. That's a question you would have to take up with Respironics.

Gonna throw out a WAG here, but I think it has something to do with the complexity of the algorithm. IIRC RC looks at peak, roundness, flatness and skewness of waveforms; then if it's getting better, staying the same or getting worse; then over short-term and long-term; then compiling these values into a "vote" and the machine responds. If it's not in Auto Mode there's' no reason to report all that stuff. If it is in Auto Mode the end result isn't too meaningful for an end user.

So why are are FLs reported at all? And so sporadically? Perhaps only to identify them if they occur during Pther which is a holding period but for why IDK.

Alternative WAGs welcome.

[Pugsy]

In fixed mode the Respironics machines don't record FLs at all. Doesn't mean they didn't happen....just means they didn't get recorded or flagged. Don't know why Respironics decided that FLs weren't worth reporting in fixed mode unless maybe since in fixed mode the pressure can't change so the FLs weren't worth flagging. That's a question you would have to take up with Respironics.

Gonna throw out a WAG here, but I think it has something to do with the complexity of the algorithm. IIRC RC looks at peak, roundness, flatness and skewness of waveforms; then if it's getting better, staying the same or getting worse; then over short-term and long-term; then compiling these values into a "vote" and the machine responds. If it's not in Auto Mode there's' no reason to report all that stuff. If it is in Auto Mode the end result isn't too meaningful for an end user.

So why are are FLs reported at all? And so sporadically? Perhaps only to identify them if they occur during Pther which is a holding period but for why IDK.

Alternative WAGs welcome.

I don't have a WAG to offer. I always thought that Respironics decision to not even flag FLs in fixed mode was kinda stupid way of doing things IMHO After all it might be nice to know at least that something is occurring (and not being addressed) that if the mode was auto the machine might try to go killing with more pressure.
In theory anyway...a person could have a boatload of FLs and not know it and might be having some issues related to those FLs and in fixed mode....no clue as to what might be causing the issues if they were FL related.

I guess they decided that since they can't do anything about them in fixed mode that it would be best to stick the head in the sand and pretend nothing is going on. That's going to really help someone....not.