Tidal volume and Flow limitations

[Morbius]

1) All I, an unknowing novice, write about sleep should be taken with a cup of salt and will, I hope, be challenged with constructive criticism.

OK.

Everything under "Post-OA RR&TV relationship:" is wrong.

[Morbius]

For that matter, I would also take all that text under the graphs and edit to:

0330. Rolled on back. Therapy is less gooder.

[Morbius]

For that matter, I would also take all that text under the graphs and edit to:

0330. Rolled on back. Therapy is less gooder.

OTOH, if I were to renege on my promises of

Now, my responses will not be quite as thorough as yours because

1. Using something like WordPad prevents post loss but I ain't doing that.
2. Signing up for an image host allows posting of images, but I ain't doing that.
3. Long drawn-out posts provide-- well I don't know what they provide. So I ain't doing that.

and post



I would be like "WTF happened after 0330?" I mean, yeah, there is instability; yet, there seems to be a certain stability to the instability i.e., a pattern. This is especially noted in I: and E:times. Why is that? Prolonged wake? CAP (although by definition, this would require total absence of REM)(OTOH there doesn't look like there's a REM period in there either)? CompSAS because of the increased pressures?

There's those inquiring minds again!

[Morbius]

CompSAS because of the increased pressures?

And that's a very aggressive attack we're talking about here.

[Morbius]

CompSAS because of the increased pressures?

And that's a very aggressive attack we're talking about here.

Perhaps explaining the prolonged duty cycle, i.e., the lung's elasticity has been compromised.

[AmSleepnBetta]

Thank you for that remainder, Morbius, and BTW, did PR assign you a mission here, where his embarrassing early-thread dicta (e.g., "there is no connection between flow limitations and tidal volume") are being read too widely?

Wellll, let's talk about that a little. Cause actually, in many of the examples of flow limitation you and daquill have posted, no reduction in tidal volume occurs. And indeed, that's the whole purpose of increasing duty cycle, namely preserving tidal volume.

That said, you do have one example where there is tidal volume reduction in the face of severe flow limitation, but frankly, that flow limitation is so severe I would score that as a hypopnea (at the least).

Again, thank you for confirming my opening header and main purpose and point made in notes for the 7 hour graphic. I stated it showed duty cycle defending TV against FL. And of course, my overall respiratory defense maintained TV against the effect of FL. In the 7 hour view you can see the upper envelope of blue TVd indicators reflect loss of OSCAR TV's due-to/along-with rises of RR as the post or image notes explained. The 7 hour mass of FL, no, cannot be correlated at that scale, but correlation is obvious in 52 minute and 2 minute views.

First, what a reach for PR's benefit! Aint't buying it if you say some remote FL you or he find, driven by wave shape alone, say, is going to prove his case that there is no connection between FL and TV.

The most charitable thing I can write is get your glasses checked to see TV reductions. And, no not all reductions: I am going to show only those marked accordingly, maybe a few extra. Go do equivalent legitimate work somewhere to present evidence and prove me wrong.

List of dates and times will follow when penciled notes are spreadsheeted maybe tomorrow. It will list significant (lagging) rolling average TV lows OSCAR presents and my high data rate TVd (TV drops). That done, I'll ignore further pettifogging, but will answer this rubbish one more time.

For readers and a bit for Morbius:

Five factors here:

--small rises and falls of TV at compressed vertical scales used look insignificant;

--rolling averages of TV lag real time reductions of TV;

--local high I/E ratios, duty cycles and respiratory rates show TV being maintained against FL when the respiratory system is capable--again, thank you very much for reinforcing that main thrust of my work breathing in the 7-hour view and typing later posts showing it here, Morbius;

--a FL flag may entail only a small drop (if any) in TV if driven primarily by wave shape, duty cycle or respiratory rate . A small image up-thread shows Resmed contributors to FL flags from? NIH? (My first graphic with notes--page 1?--in this thread contrasts TV drops with FL, both descending along the same axis. Those yellow and rust drops and the red and rust drops from the axis are plots from raw Resmed data generated by the Resmed Autoset device of another person. (Read it with good glasses, Morbius. There aren't many perfect matches of Resmed FL with TV drops anywhere for reasons stated and as graphed in yellow as mentioned..)

--if one could suck hard continuously on a 1/4 inch straw at a steady rate, flow restricted/limited as that would be, there would be no drop in flow rate or tidal volume , but flow rate and volume of air would be vastly flow limited and reduced compared to doing that with a 1/2 inch straw--a kind of small airway UARS analogy.

[Morbius]

Thank you for that remainder, Morbius, and BTW, did PR assign you a mission here, where his embarrassing early-thread dicta (e.g., "there is no connection between flow limitations and tidal volume") are being read too widely?

Wellll, let's talk about that a little. Cause actually, in many of the examples of flow limitation you and daquill have posted, no reduction in tidal volume occurs. And indeed, that's the whole purpose of increasing duty cycle, namely preserving tidal volume.

That said, you do have one example where there is tidal volume reduction in the face of severe flow limitation, but frankly, that flow limitation is so severe I would score that as a hypopnea (at the least).

Again, thank you for confirming my opening header and main purpose and point made in notes for the 7 hour graphic. I stated it showed duty cycle defending TV against FL. And of course, my overall respiratory defense maintained TV against the effect of FL. In the 7 hour view you can see the upper envelope of blue TVd indicators reflect loss of OSCAR TV's due-to/along-with rises of RR as the post or image notes explained. The 7 hour mass of FL, no, cannot be correlated at that scale, but correlation is obvious in 52 minute and 2 minute views.

First, what a reach for PR's benefit! Aint't buying it if you say some remote FL you or he find, driven by wave shape alone, say, is going to prove his case that there is no connection between FL and TV.

The most charitable thing I can write is get your glasses checked to see TV reductions. And, no not all reductions: I am going to show only those marked accordingly, maybe a few extra. Go do equivalent legitimate work somewhere to present evidence and prove me wrong.

List of dates and times will follow when penciled notes are spreadsheeted maybe tomorrow. It will list significant (lagging) rolling average TV lows OSCAR presents and my high data rate TVd (TV drops). That done, I'll ignore further pettifogging, but will answer this rubbish one more time.

For readers and a bit for Morbius:

Five factors here:

--small rises and falls of TV at compressed vertical scales used look insignificant;

--rolling averages of TV lag real time reductions of TV;

--local high I/E ratios, duty cycles and respiratory rates show TV being maintained against FL when the respiratory system is capable--again, thank you very much for reinforcing that main thrust of my work breathing in the 7-hour view and typing later posts showing it here, Morbius;

--a FL flag may entail only a small drop (if any) in TV if driven primarily by wave shape, duty cycle or respiratory rate . A small image up-thread shows Resmed contributors to FL flags from? NIH? (My first graphic with notes--page 1?--in this thread contrasts TV drops with FL, both descending along the same axis. Those yellow and rust drops and the red and rust drops from the axis are plots from raw Resmed data generated by the Resmed Autoset device of another person. (Read it with good glasses, Morbius. There aren't many perfect matches of Resmed FL with TV drops anywhere for reasons stated and as graphed in yellow as mentioned..)

--if one could suck hard continuously on a 1/4 inch straw at a steady rate, flow restricted/limited as that would be, there would be no drop in flow rate or tidal volume , but flow rate and volume of air would be vastly flow limited and reduced compared to doing that with a 1/2 inch straw--a kind of small airway UARS analogy.

Please get a better translator. I have NFI what you're talking about.

[Morbius]

But while you're looking for that:

Five factors here:

--small rises and falls of TV at compressed vertical scales used look insignificant; Thank you Captain Obvious

--rolling averages of TV lag real time reductions of TV; Thank you again Captain Obvious

--local high I/E ratios, duty cycles and respiratory rates show TV being maintained against FL when the respiratory system is capable-- So you're simultaneously rejecting and accepting palerider's contention?

--a FL flag may entail only a small drop (if any) in TV if driven primarily by wave shape, duty cycle or respiratory rate This is either completely irrelevant or a haphazard collection of unrelated terminology.

--if one could suck hard continuously on a 1/4 inch straw at a steady rate, flow restricted/limited as that would be, there would be no drop in flow rate or tidal volume , but flow rate and volume of air would be vastly flow limited and reduced compared to doing that with a 1/2 inch straw--a kind of small airway UARS analogy. Once again, thank you Captain Obvious

[Morbius]

And BTW, you should untie the knot in your panties from this tirade

First, what a reach for PR's benefit! Aint't buying it if you say some remote FL you or he find, driven by wave shape alone, say, is going to prove his case that there is no connection between FL and TV.

The most charitable thing I can write is get your glasses checked to see TV reductions. And, no not all reductions: I am going to show only those marked accordingly, maybe a few extra. Go do equivalent legitimate work somewhere to present evidence and prove me wrong.

Because in actuality I didn't say palerider was right, nor did I say he was wrong. Specifically, I said,

... in many of the examples of flow limitation you and daquill have posted, no reduction in tidal volume occurs. And indeed, that's the whole purpose of increasing duty cycle, namely preserving tidal volume.

That said, you do have one example where there is tidal volume reduction in the face of severe flow limitation, but frankly, that flow limitation is so severe I would score that as a hypopnea (at the least).

But if you're asking me for my opinion (based on "Go do equivalent legitimate work somewhere") I need to respond with another "Well duh!" as FLs progress in severity through hypopnea and eventually to apnea, Vt eventually falls to -0-.

Duh.

That said, I wouldn't be putting a lot of stock in the accuracy of Vt measurements as they are extrapolated from the flow waveform. With about 30 L/M blowing by there (depending on what you're running) the margin of error is tremendous.

AAMOF if you ask ResMed it's +/-20%.

[Morbius]

The image shows a large Resmed Autoset FL flag of severity 0.79 and its relation to (a) actual tidal volume drop, my novel breath by breath drop basis (TVd), (b) usual Resmed moving average TV, (c) breathing work done as shown in the duty cycle ratio dC=Ti/(Ti+Te) and (d) all the other most relevant curves OSCAR presents showing Resmed sleep data from air flow.

The main takeaway--beyond whatever interrelationships the image may help one understand better--is highlighted as item "b" and explained some as matching item "B" in the text box below "b". Box "b" values are readouts from Insp. and Exp. Time curves where the green cursor intersects the two curves (Insp. curve above Exp. Curve) where the curves diverge and are most apart in the view. The same can be done by anyone having certain Resmed devices that report or make data available to OSCAR for showing inspiratory and expiratory times. The method can be used to assess sleep work done to fight flow limitation (whether flagged by FL or shown as any form of apnea or neither).

The single relevant research I've seen determined that normal sleepers, as tested, had a duty cycle ratio ("dC", I call them) of about 0.42 and sleepers with severe upper airway obstruction (UAO) had a ratio of about 0.53. As mentioned elsewhere, a Resmed patent application noted, however, that the ratio is about 0.3 for sleeping state and 0.4 for wake state.

Explanation of the TVd (in L) and dC ratio graphs:

Actual values were multiplied by 100 to enable use of the Somnopose import feature of OSCAR. (For example, a tidal volume of 0.5 would otherwise barely register in graph structure built for a range of 0 to 180, similarly for a duty cycle below 1.0).

TVd: bars or spikes upward show loss of tidal volume to flow limitation of any kind while spikes downward show the extra tidal volume over the baseline tidal volume of 0.5 for larger breaths. In a sense that is logically backward, but done that way to make FL flags be more easily compared to TVd, both increasing upward.

dC: The gray bar across the graph was intended to make it easier to estimate bar height; bottom edge agreeing with the first (lowest, 1/4 window height tic) tic mark at left, top edge agreeing with next to top (highest 3/4 height tic) tic mark at left. Anything between 1/4 and 3/4 could be visually estimated more easily from those edges.

I suggest taking notice of the relative timings, durations and magnitudes of all the curves' signals because those are typical of what I see in such analyses.

Yeah I read that already.

Is there supposed to be an answer to anything in there?

Otherwise, and from a practical point of view, it can all be boiled down to

As FLs progress in severity through hypopnea and eventually to apnea, Vt eventually falls to -0-.

And as previously noted, IMO that event should have been scored as a hypopnea rather than a RERA. Let me get your cartoon as apparently you're too MF lazy to get it..

[Morbius]

The thing that seems to have gotten lost here is that there is no connection between flow limitations and tidal volume.

TV reduction is a hypopnea, which is separate and distinct from a flow limitation. It would perhaps be more meaningful if the term were "flow rate limitation", not simply FL.

So, what we have are FRL and FVL, Flow Rate Limitations (typically called FL) and Flow Volume Limitation (called hypopnea).

This is what ASB should have challenged, as all scoring (machine algorithms, AASM, Morbius the Right Wing Second Amendment Fanatic) is done on the flow channel.

IMO there is a 50% reduction in flow during this event.

Now, you can argue "50% of what"?

If we take ASB's "novel" VT drop (IDK if it's actually "novel" or not, but whatever) and flow limitation identification it would appear that the ResMed algorithm is a little confused as to what a "normal" breath (or baseline) should be. Consequently the 50% target is just missed and the event is scored as RERA.

Do we care? The machine responded and seemingly quite aggressively so probably not.

[Morbius]

As an aside, if the algorithm was using VT to score respiratory events (and again the margin of error there is enormous, so it wouldn't) it should have actually scored that event as an apnea!

[Morbius]

Oh damn.

Once any SAG character hits 1000 posts he is forced to disappear.

Oh well, been fun, you kids take care!

[zonker]

Oh damn.

Once any SAG character hits 1000 posts he is forced to disappear.

Oh well, been fun, you kids take care!

could someone explain this to me?

[Pugsy]

Oh damn.

Once any SAG character hits 1000 posts he is forced to disappear.

Oh well, been fun, you kids take care!

could someone explain this to me?

His way of saying "bye".