420E Run Question ???

[NightHawkeye]

Recently, I have been successful at narrowing the APAP range. That has, not surprisingly, resulted in lower AHI and better sleep quality. However, the somewhat higher overall pressure has resulted in a greater number of "Runs", which according to the SilverLining book is a form of flow limitation.

When I used a wider range of 5.5 - 12 cm, the "Runs" coincided with higher pressure, but when the machine was operating at reduced pressure there were generally no "Runs". That seemed to make sense.

However, a quite different pattern of near-constant "Runs" has been apparent over the past couple of weeks with the APAP range set to 8.0 - 10.5 cm, as can be seen in data for the past couple of nights.



For comparison, the following chart shows the results when the APAP range was set much wider. In this chart the "Runs" coincide with times of increased pressure.



So I'm left wondering what the implications, if any, of this pattern of near-constant "Runs" might be. My first inclination has been that they are related to nasal congestion, but my charts have consistently shown some "Central Apneas" and I'm left wondering if the increased pressure isn't simply triggering the "Runs" in a similar way to the way increased pressure triggers central apnea.

Anybody else see something like this in their own data?

Regards,
Bill
P.S. The CA event at the end of the night in the first chart was apparently "real" as it is what woke me up.

[Snoredog]

they need to use your graphs in the Silverlining manual.

way too many flow runs for me, the question is HOW do you feel with those settings?

When you partially squeeze off a apnea or hypopnea what is left is Flow Limitation and LOTS of them. Still appears to be a struggle to breathe,

if you drew a line across your Initial pressure at 7.0cm you would take care of a lot of those, 8.0 even better but you are probably using that range for your aerophagia.

My suggestion would be:

Increase Initial pressure to 7.0cm and disable IFL1. Then it won't respond so agressively to stand alone FL's. Those "blocks" of pressure would turn into peaks and valleys on the pressure front.

By disabling FL1 you get an overall lower pressure, that in itself might help your aerophagia.

AHI is not everything, FL's are not included in that calculation, they are calculated in the other screen. But you have nearly a solid blue line of Flow Limited Runs, looks like nearly every breath is a FL.

What does your Cycle state show?

[ozij]

I always have many runs - I think they are the result of congestion. My usual cycle state is about 70% normal, and I can never get rid of the flow limitations.
My best ever has been 85%, and yes, the "no runs" part of my data has lower pressures. I don't think your flow limitation are triggered by the pressure, you machine is dropping the pressure when it can, rasing it when necessary. My guess is that having more runs now is a either congestion related, or a coincidence.

O.

[Snoredog]

Do you have IFL1 disabled in the above graphs?

It looks like it is enabled to me based upon the pressure trends shown.

Make NO other changes other than unchecking that IFL1 box and I bet you get a totally different looking report with half as many FL Runs. My report used to look like that with IFL1 enabled.

I too would get a CA early in the morning just before waking (think that was what woke me also).

[NightHawkeye]

they need to use your graphs in the Silverlining manual.

way too many flow runs for me, the question is HOW do you feel with those settings?

LOL. At least you didn't say my sleep looked like a trainwreck, Snoredog. Actually, I feel pretty good. Still don't get enough sleep. Averaging about six hours now without too many awakenings. On a really good night, maybe seven hours.

Increase Initial pressure to 7.0cm and disable IFL1.

You're right on both counts, Snoredog. I disabled IFL1 the first night or two I had the machine. IFL1 ON just didn't work for me.

AHI is not everything, FL's are not included in that calculation, they are calculated in the other screen. But you have nearly a solid blue line of Flow Limited Runs, looks like nearly every breath is a FL.

What does your Cycle state show?

The Cycle state tends toward "Normal" which would seem to be in contradiction to the constant "Runs".

I always have many runs - I think they are the result of congestion. My usual cycle state is about 70% normal, and I can never get rid of the flow limitations. My best ever has been 85%, and yes, the "no runs" part of my data has lower pressures.

Oh good! I'm not the only one with this kind of data. (That's a relief.)

I'm gonna go with congestion as the likely explanation, then. I'm aware of congestion even now. I'll take the "Runs" as another indicator that I have work to do minimizing congestion. An issue I've been experiencing related to congestion is my eustachian tube has been getting plugged frequently at the higher pressure settings. That's one of the primary problems which wakes me up these days.

Thanks for all the comments.

Regards,
Bill

[-SWS]

Bill, please let us know if you spot any more patterns with respect to excessive 420e flow runs.

As an unrelated side note, I have poorly functioning Eustachian tubes according to my ENT. My Eustachian tubes more often than not clog when I have nasal congestion. And yet, I don't have to have any nasal congestion to suffer clogged Eustachian tubes. Also, I don't seem to score significant FL runs on the 420e with any combination of ear or nose congestion!

I half expect that a correlation may one day show up between excessive FL runs on the 420e and excessive cyclic alternating pattern (CAP) in the sleep lab. Right now medicine seems to be at the very preliminary stages of attempting to decode and understand sleep-related CAP activity.

[ozij]

Bill,
Did you ever compare your flow limitation runs no. (or index) with what you got on the Respironics, when you used both machines at about the same time of the year?

I have always found it amazing that people like Rested Gal and myself have about 30% flow limited breath per night. And that doesn't seem to change much, no matter what the pressure.

On the other hand, despite Respironics' anouncement that in the auto algorithm Once flow limitation is observed, the algorithm increases the pressure in response to the flow limitation., it doesn't seem to run wild for those people who can't tolerate PB's flow limitation response. So what is going on here?

Supposing the PB is perfectionist, and tends to identify far more breaths as flow limited - by definition - than does a Respironics?

Heres how PB defines (and identifies) events:

Event Descriptions
When is apnea said to have occurred?
An apnea event occurs when there is no airflow for a time equal to at least 10 seconds plus 5/8 of an average breath period.
When is central apnea said to have occurred?
A central apnea event occurs when cardiac oscillations can be detected during an apnea event. The cardiac oscillations indicate an open airway, which is not an obstructed situation.
When is hypopnea said to have occurred?
A hypopnea event occurs when there is a period of at least 10 seconds where hypopneic breathing occurs. Hypopneic breathing is considered to be a reduction in breathing peak airflow by at least 40% when compared to the average of the preceding eight breaths, but not enough reduction to be considered an apnea. A hypopnea event is terminated when the patient delivers 2 consecutive non-hypopneic breaths.
When is snoring said to have occurred?
A snoring event is declared by the microcontroller when there has been an acoustical vibration for at least 7% of the average breath period time of the three preceding breath cycles and if the time between snoring doesn’t exceed 120% of the average breath period.
When is flow limitation said to have occurred?
Flow limitation events are determined from breath wave shapes. Flow limited breaths occur when the patient’s throat partially closes (thus reducing airflow) during the middle stage of inhalation.

Flow limitations in the PB are apparently derived when your breathing is be compared to something absolute. They were very specific about the other parameters, not so here. Either its as simple as they show in the manual, or else, maybe its a half baked idea?

Not so Respironics. For Respironics, a flow limitation" is relative to your breathing pattern (my emphasis:.

The flow limitation algorithm analyzes the inspiratory airflow waveform. It looks for relative changes in the roundness, flatness, peak, or shape ("skewness") of the inspiratory portion of the airflow waveform. These changes are observed both over a short period of time (groups of 4 breaths) and over a long period of time (several minutes). Statistical measures are used to help minimize false event detection while allowing the device to be sensitive to even small changes. For example, a change needs to be observed in at least two of the measures before a response is initiated.

I bumped the poll up because I was thinking of this...

And why would PB need to distinguish a "flow limited hypopnea" from and "amplitude decrease" hypopnea? And having done that, why refrain from responding to amplitude decrease hypopneas when the IFL1 (don't respond to flow limited runs[/b)] is off? What's wrong with responding to an amplitude decrease hypopnea -- which is actually what a hypopnea is defined as - when told not respond to flow limitation runs? That's ridiculous! This is beginning to feel more and more like a "this is a feature not a bug" situation to me.

And while I'm venting my frustration: Has anyone found a difference in response for IFL2 (the one that's supposed to control response to amplitude decrease hypopneas?) My machine couldn't care less if its on or off - I swear some in PB had some wires crossed along the way!

OK. Venting finished.


O.

[Snoredog]

Bill,
Did you ever compare your flow limitation runs no. (or index) with what you got on the Respironics, when you used both machines at about the same time of the year?

I have always found it amazing that people like Rested Gal and myself have about 30% flow limited breath per night. And that doesn't seem to change much, no matter what the pressure.

On the other hand, despite Respironics' anouncement that in the auto algorithm Once flow limitation is observed, the algorithm increases the pressure in response to the flow limitation., it doesn't seem to run wild for those people who can't tolerate PB's flow limitation response. So what is going on here?

Supposing the PB is perfectionist, and tends to identify far more breaths as flow limited - by definition - than does a Respironics?

Heres how PB defines (and identifies) events:

Event Descriptions
When is apnea said to have occurred?
An apnea event occurs when there is no airflow for a time equal to at least 10 seconds plus 5/8 of an average breath period.
When is central apnea said to have occurred?
A central apnea event occurs when cardiac oscillations can be detected during an apnea event. The cardiac oscillations indicate an open airway, which is not an obstructed situation.
When is hypopnea said to have occurred?
A hypopnea event occurs when there is a period of at least 10 seconds where hypopneic breathing occurs. Hypopneic breathing is considered to be a reduction in breathing peak airflow by at least 40% when compared to the average of the preceding eight breaths, but not enough reduction to be considered an apnea. A hypopnea event is terminated when the patient delivers 2 consecutive non-hypopneic breaths.
When is snoring said to have occurred?
A snoring event is declared by the microcontroller when there has been an acoustical vibration for at least 7% of the average breath period time of the three preceding breath cycles and if the time between snoring doesn’t exceed 120% of the average breath period.
When is flow limitation said to have occurred?
Flow limitation events are determined from breath wave shapes. Flow limited breaths occur when the patient’s throat partially closes (thus reducing airflow) during the middle stage of inhalation.

Flow limitations in the PB are apparently derived when your breathing is be compared to something absolute. They were very specific about the other parameters, not so here. Either its as simple as they show in the manual, or else, maybe its a half baked idea?

Not so Respironics. For Respironics, a flow limitation" is relative to your breathing pattern (my emphasis:.

The flow limitation algorithm analyzes the inspiratory airflow waveform. It looks for relative changes in the roundness, flatness, peak, or shape ("skewness") of the inspiratory portion of the airflow waveform. These changes are observed both over a short period of time (groups of 4 breaths) and over a long period of time (several minutes). Statistical measures are used to help minimize false event detection while allowing the device to be sensitive to even small changes. For example, a change needs to be observed in at least two of the measures before a response is initiated.

I bumped the poll up because I was thinking of this...

And why would PB need to distinguish a "flow limited hypopnea" from and "amplitude decrease" hypopnea? And having done that, why refrain from responding to amplitude decrease hypopneas when the IFL1 (don't respond to flow limited runs[/b)] is off? What's wrong with responding to an amplitude decrease hypopnea -- which is actually what a hypopnea is defined as - when told not respond to flow limitation runs? That's ridiculous! This is beginning to feel more and more like a "this is a feature not a bug" situation to me.

And while I'm venting my frustration: Has anyone found a difference in response for IFL2 (the one that's supposed to control response to amplitude decrease hypopneas?) My machine couldn't care less if its on or off - I swear some in PB had some wires crossed along the way!

OK. Venting finished.


O.

[NightHawkeye]

Do you have IFL1 disabled in the above graphs?

It looks like it is enabled to me based upon the pressure trends shown.

IFL1 is truly OFF. The machine display says 0, and the software settings display for the past 96 hours of data is as shown below:



Now, IFL2 is ON, but not IFL1. According to the SilverLining manual:
IFL1 - Command on Flow Limitation Run
IFL2 - Command on Flow Limitation Run combined with an amplitude decrease

I really wasn't even aware of IFL2 until recently. (Doesn't mean I didn't inadvertently change it earlier though. )

Careful reading too much into the older 418"A" manual, it is a totally different animal to the 418"P".

The 418"P" and the 420E are functionally identical but the 418A is not.

Nevertheless, the 420E manual has the same exact definitions which ozij quoted. Additionally, the 420E manual states:

The GoodKnight Evolution uses the same event detection technology as does the GoodKnight 418A.

In Bill's case it appears he has IFL1 checked (based upon my view of the pressure response seen). That is why FL runs correspond with pressure increases on his graph.

LOL. Well, despite appearances IFL1 is unchecked and definitely OFF. Hmm, the mystery deepens ... Here's last night's data (along with the night before) which seems different mainly in that the machine went up to maximum pressure and stayed there for a while. There was a short period without flow-limitation "Runs" as well.

Bill,
Did you ever compare your flow limitation runs no. (or index) with what you got on the Respironics, when you used both machines at about the same time of the year?

I have always found it amazing that people like Rested Gal and myself have about 30% flow limited breath per night. And that doesn't seem to change much, no matter what the pressure.

Well, the data is so different I never did a direct comparison before, Ozij. I do, however, have data from one year ago from the Remstar:



Somehow, the machine came up with an FLI of 1.1 above. In some of the other charts I looked at briefly, the FLI was simply 0. Obviously, there's a difference between how Respironics and PB calculate flow limitation. It also appears that my own breathing pattern doesn't seem to fit either one particularly well.

Regards,
Bill

[-SWS]

Bill, is your 420e set to increase pressure with 0.5 cm increments or 1.0 cm increments instead? You might want to experimentally set your pressure increments to 0.5 cm if your machine is not already set that way.

Also, consider setting your initial pressure equal to your minimum pressure (yup---"hobble" the 420e's pressure attack pattern). If your excessive flow runs diminish after those two experiments, then this thread is going to get extremely interesting.

[-SWS]

And why would PB need to distinguish a "flow limited hypopnea" from and "amplitude decrease" hypopnea?

Because a "flow limited hypopnea" has high statistical probability of being a nice, safe, epidemiologically "pressure-increase-friendly" obstructive hypopnea.

By contrast an "amplitude decrease hypopnea" (remiss of those FL wave-shape nuances that are characteristic of obstruction) shows no sure signs of being obstructive versus central. That type of hypopnea stands a much better chance of being either a benign or SDB-related central hypopnea. APAP manufacturers generally do not want to increase pressure on either of those two central hypopnea types.

A "flow limited hypopnea" by the 420e's definition meets both amplitude and shape criteria by embodying: 1) a time-based amplitude decrease (hence "hypopnea"), and 2) a flow-limited or obstructive wave shape (hence this is specifically an "obstructive hypopnea"). That dual criteria is controlled by the 420e's IFL2 parameter---with IFL2 as an on/off trigger or on/off response-switch specifically for those highly-probable obstructive hypopneas.


In summary: turn IFL2 off and the 420e won't trigger on any hypopneas; leave IFL2 on and the 420e will trigger specifically on hypopneas that are safely accompanied by an obstruction-differentiating FL wave shape (referred to here as "flow limited hypopneas").

[NightHawkeye]

Bill, is your 420e set to increase pressure with 0.5 cm increments or 1.0 cm increments instead?

Can you change that? I've been under the impression that it's been set to 0.5 cm increments because I've made pressure adjustments at 0.5 cm points. Looking at the data charts though it appears the machine is changing in increments finer than 0.5 cm, more like 0.25 cm. Does that make sense?

Also, consider setting your initial pressure equal to your minimum pressure (yup---"hobble" the 420e's pressure attack pattern). If your excessive flow runs diminish after those two experiments, then this thread is going to get extremely interesting.

OK, in the interest of science, of course ... FWIW, After spending four hours outside doing yard work, I was congested most of the day. Only in the past hour being inside with well-filtered air has my congestion diminished. Since I know I'm congested during the day a lot, it's easy for me to jump to the conclusion that the runs are related to congestion. That thought gets me wondering whether I ought to see an ENT about it. It's been on my short list of things to do for quite a while now.

In summary: turn IFL2 off and the 420e won't trigger on any hypopneas; leave IFL2 on and the 420e will trigger specifically on hypopneas that are safely accompanied by an obstruction-differentiating FL wave shape (referred to here as "flow limited hypopneas").

I sure am glad you took the time to explain that, -SWS. I spent a few minutes carefully reading and re-reading the words in the manual without getting a clue about the implications.

In my case it seems obvious enough that the flow-limited hypopneas are triggering much of the pressure increases, but not the flow-limited "runs", per se. (Looking back at the charts now though, I wonder what sense any of this makes.) Anyway, something's triggering the pressure increases. Which brings me back to the starting point of whether the "runs" might not be "central" related ...,

Regards,
Bill (who realizes he has become incoherent, and is going to bed ... )

[ozij]

Thaks for checking, Bill. I had noticed that major difference in Respironics FL as opposed to PBs elsewhere as well.

If you point your crossbar tool at the exact point where all flow limitation runs disappear, I think you'll see that's where the pressure dropped. And the machine didn't drop the pressure before that because you were leaking rather badly.

And yes (thank you...), I went to the 418/A + P SilverLining manual because that is what the 420E told me to do. My quote comes from page 37, "Detection of Respiratory Events" under the main chapter "Displaying real time data capture for 418/P"

And why would PB need to distinguish a "flow limited hypopnea" from and "amplitude decrease" hypopnea?

Because a "flow limited hypopnea" has high statistical probability of being a nice, safe, epidemiologically "pressure-increase-friendly" obstructive hypopnea.

By contrast an "amplitude decrease hypopnea" (remiss of those FL wave shape nuances that are characteristic of obstruction) shows no sure signs of being obstructive versus central. That type of hypopnea may be either a benign or pathological central hypopnea, and APAP manufacturers generally do not want to increase pressure on either of these central hypopnea types.

A "flow limited hypopnea" by the 420e's definition meets both amplitude and shape criteria by embodying: 1) a time-based amplitude decrease (hence "hypopnea"), and 2) a flow-limited or obstructive wave shape (hence this is specifically an "obstructive hypopnea"). That dual criteria is controlled by the 420e's IFL2 parameter---with IFL2 as an on/off trigger or on/off response-switch for those highly-probable obstructive hypopneas.


In summary: turn IFL2 off and the 420e won't trigger on any hypopneas; leave IFL2 on and the 420e will trigger specifically on hypopneas that are safely accompanied by an obstruction-differentiating FL wave shape (referred to here as "flow limited hypopneas").

[-SWS]

Bill, is your 420e set to increase pressure with 0.5 cm increments or 1.0 cm increments instead?

Can you change that?

My mistake, Bill. You can definitely change APAP pressure increments on the old Resmed AutoSets (and maybe the new ones as well). I don't have a 420e set up right now. But I think you're right about the 0.5 cm hard-coding on that model.

Which brings me back to the starting point of whether the "runs" might not be "central" related ...,

That's essentially what I'm wondering as well. Or perhaps I'm wondering about a slightly modified version of that same premise. Okay. I'm thinking about your aerophagia and your occasional frank central events... I'm also going back to your very first post about those mysterious cardiac episodes...

I'm specifically wondering whether your FL runs are slight albeit defensive airway closures. And if they are physiologically-defensive closures (as opposed to allergy congestion) are they defensive in response to the 420e's pressure changes?

That was why I was wondering about an experiment in which you severely restrict your 420e's pressure swings. Like you, I'm wondering whether those FL runs might be aggravated by the 420e's pressure swings.

And I'm still wondering whether your somewhat unique etiology makes you a good candidate for excessive cyclic alternating pattern (CAP). Also wondering about an alternate or even complementary possibility of a very slight CompSA/CSDB tendency. Please forgive my wondering out loud, Bill. I honestly don't mean to be rude.

[ozij]

Recently, I have been successful at narrowing the APAP range. That has, not surprisingly, resulted in lower AHI and better sleep quality. However, the somewhat higher overall pressure has resulted in a greater number of "Runs", which according to the SilverLining book is a form of flow limitation

That was why I was wondering about an experiment in which you severely restrict your 420e's pressure swings. Like you, I'm wondering whether those FL runs might be aggravated by the 420e's pressure swings.

Bill setup has the machine rushing up quickly from minimum to almost maximum and going down rather slowly (disregard the post-leak correction) . -SWS's suggestion would having it going up slowly, and rushing down. You can use SL3 to chose .5 or 1 for the increment, its not hard coded.

How about a lower humidifier temp, now that the ambient air is (presumably) not as dried up by winter heating?
O.