Flow limitation: when are they considered significant?

musculus wrote:I have reviewed my sleep study data sec by sec and most of my microarousals were caused by flow limitations.

Are you able to upload the study for review to more closely examine this phenomenon?

TIA.

tan wrote:

Wulfman... wrote:

tan wrote:

Morbius wrote:

Wulfman... wrote:Could be caused by congestion, sleep position, or other possibilities on random nights.

Or artifact (like movement after arousal).

And chasing sleep fragmentation with pressure may not be the best approach.

Unless such fragmentation is caused by flow limitation?

Is there a reliable way at home to understand what causes what? I guess only statistical approach. Accumulate data with different pressures for several nights. Right?

Well, the flow limitations elicit a response of increased air pressure from the machine. It COULD be the pressure changes are disturbing (fragmenting) your sleep.


Den

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Which means that if the pressure does not raise in response to FL (fixed), then there will be no arousal? This argument fails based on the experiences shared by UARSers.

Besides, according to this study "Auto-CPAP therapy for obstructive sleep apnea: induction of microarousals by automatic variations of CPAP pressure?", it caused micro-arousal only for small portion of subjects.

From my perspective, that's a generalization you're making......based on OTHER peoples' experiences.


Den

.

Wulfman... wrote:

tan wrote:

Wulfman... wrote:

tan wrote:

Morbius wrote: Or artifact (like movement after arousal).

And chasing sleep fragmentation with pressure may not be the best approach.

Unless such fragmentation is caused by flow limitation?

Is there a reliable way at home to understand what causes what? I guess only statistical approach. Accumulate data with different pressures for several nights. Right?

Well, the flow limitations elicit a response of increased air pressure from the machine. It COULD be the pressure changes are disturbing (fragmenting) your sleep.


Den

.

Which means that if the pressure does not raise in response to FL (fixed), then there will be no arousal? This argument fails based on the experiences shared by UARSers.

Besides, according to this study "Auto-CPAP therapy for obstructive sleep apnea: induction of microarousals by automatic variations of CPAP pressure?", it caused micro-arousal only for small portion of subjects.

From my perspective, that's a generalization you're making......based on OTHER peoples' experiences.

Isn't what you are doing, as one of our esteemed members pointed out? But I am also speaking from my experience. If I generalize, then so do you.

Let's apply some logic here then, shall we?

If you have a person with a low AHI, 1 (untreated), and moderate RDI, 30 (untreated), for instance, then per your argument, there will no necessity for xPAP at all, right? Indeed, flow limitations never materialize into full fledged apneas/hypopneas, they are therefore not worth pursuing. Since AHI is low, xPAP is not needed. Am I missing anything?

tan wrote:Isn't what you are doing, as one of our esteemed members pointed out? But I am also speaking from my experience. If I generalize, then so do you.

Let's apply some logic here then, shall we?

If you have a person with a low AHI, 1 (untreated), and moderate RDI, 30 (untreated), for instance, then per your argument, there will no necessity for xPAP at all, right? Indeed, flow limitations never materialize into full fledged apneas/hypopneas, they are therefore not worth pursuing. Since AHI is low, xPAP is not needed. Am I missing anything?

This esteemed member? I'll "buy" what he's selling.

Morbius wrote: Or artifact (like movement after arousal).

And chasing sleep fragmentation with pressure may not be the best approach.

If increased pressure doesn't reduce/subdue them, and IF they're a REAL problem, then other avenues need to be explored.


Den

.

Wulfman... wrote:

tan wrote:Isn't what you are doing, as one of our esteemed members pointed out? But I am also speaking from my experience. If I generalize, then so do you.

Let's apply some logic here then, shall we?

If you have a person with a low AHI, 1 (untreated), and moderate RDI, 30 (untreated), for instance, then per your argument, there will no necessity for xPAP at all, right? Indeed, flow limitations never materialize into full fledged apneas/hypopneas, they are therefore not worth pursuing. Since AHI is low, xPAP is not needed. Am I missing anything?

This esteemed member? I'll "buy" what he's selling.

No, the other one: you are making statements driven by your bias that you cannot prove.

Morbius wrote: Or artifact (like movement after arousal).

And chasing sleep fragmentation with pressure may not be the best approach.

If increased pressure doesn't reduce/subdue them, and IF they're a REAL problem, then other avenues need to be explored.

Well, it is not only my impression that whenever you call for straight pressure in various topics, you always refuse to consider FLs at all, as if you know that the increased pressure doesn't reduce/subdue them and they are not a real problem. You don't know that, yet you rule them out at once.

tan wrote:

Wulfman... wrote:

tan wrote:Isn't what you are doing, as one of our esteemed members pointed out? But I am also speaking from my experience. If I generalize, then so do you.

Let's apply some logic here then, shall we?

If you have a person with a low AHI, 1 (untreated), and moderate RDI, 30 (untreated), for instance, then per your argument, there will no necessity for xPAP at all, right? Indeed, flow limitations never materialize into full fledged apneas/hypopneas, they are therefore not worth pursuing. Since AHI is low, xPAP is not needed. Am I missing anything?

This esteemed member? I'll "buy" what he's selling.

No, the other one: you are making statements driven by your bias that you cannot prove.

Morbius wrote: Or artifact (like movement after arousal).

And chasing sleep fragmentation with pressure may not be the best approach.

If increased pressure doesn't reduce/subdue them, and IF they're a REAL problem, then other avenues need to be explored.

Well, it is not only my impression that whenever you call for straight pressure in various topics, you always refuse to consider FLs at all, as if you know that the increased pressure doesn't reduce/subdue them and they are not a real problem. You don't know that, yet you rule them out at once.

And, you don't know that they ARE.

viewtopic.php?f=1&t=36217&st=0&sk=t&sd= ... limitation

http://www.atsjournals.org/doi/full/10. ... QKLiI72QwA


Den

.

tan wrote:Let's apply some logic here then, shall we?

If you have a person with a low AHI, 1 (untreated), and moderate RDI, 30 (untreated), for instance, then per your argument, there will no necessity for xPAP at all, right? Indeed, flow limitations never materialize into full fledged apneas/hypopneas, they are therefore not worth pursuing. Since AHI is low, xPAP is not needed. Am I missing anything?

Yes, everything.

In your example, by definition, the FLs are creating an SBD problem (RERAs).

In this thread, the speculations are based on "Oh look! A blip on the FL Graph! It's the Apocalypse!"

Morbius wrote: "Oh look! A blip on the FL Graph! It's the Apocalypse!"

Which, BTW, is an unconfirmed blip.

I mean, you guys can't simultaneously say, "Well, if the DME, physician, therapist, sleep study, WalMart cashier, Punxsutawney Phil, etc. says it's midnight, go outside and check for yourself", but then turn around and claim the machine algorithm is the Gospel.

The biggest reason being all the UARS talk is based on spontaneous breathing. Once you get on a machine you have to account for machine-generated flow (i.e., you have the ability to engineer waveforms with a machine (make shark-fins, square waves, origami, etc.).

Morbius wrote:

tan wrote:Let's apply some logic here then, shall we?

If you have a person with a low AHI, 1 (untreated), and moderate RDI, 30 (untreated), for instance, then per your argument, there will no necessity for xPAP at all, right? Indeed, flow limitations never materialize into full fledged apneas/hypopneas, they are therefore not worth pursuing. Since AHI is low, xPAP is not needed. Am I missing anything?

Yes, everything.

In your example, by definition, the FLs are creating an SBD problem (RERAs).

In this thread, the speculations are based on "Oh look! A blip on the FL Graph! It's the Apocalypse!"

Sure, it is nothing but speculation. That is what this thread is about. When looking at a ragged FL chart for a person with low AHI who still experience symptoms of daily sleepiness, I call it a UARS suspect rather than making a definitive conclusion. Is it baseless? Should I zoom in on the flowrate chart in order to examine the waveform instead? Or it doesn't make sense to do at all because machine-generated pressure distorts the true picture a lot?

You earlier referred to an excerpt from April 2005 discussion and then followed that sometimes FLs cannot be subdued even with pressure maxing out. As you can see from my very first post of this thread, while chasing FLs, my machine never maxed out at 20 in my particular case. Also, higher initial pressure looks to take care of most of the flow limitations, and if there are any pressure rises associated with FL, such rises are minimal. Does it mean the machine's response is adequately to FLs?

Morbius wrote:

musculus wrote:I have reviewed my sleep study data sec by sec and most of my microarousals were caused by flow limitations.

Are you able to upload the study for review to more closely examine this phenomenon?

TIA.

Here comes a screen shot. row PTAF is the airflow.

A short description of my problem: I have trouble going from N2 to N3 because of arousals caused by flow limitations.

And another screenshot:

Chest and abdomen movements suggest the arousals are RERAs

Applicable? Cessation of PLM associated with elimination of FL
http://journal.publications.chestnet.or ... ID=1206613

musculus wrote:Chest and abdomen movements suggest the arousals are RERAs

Yeah, I'm really not seeing that there. Looks more like sleep stage instability (given the time) with some CAP stuff:

http://www.aastweb.org/resources/a2zzz/ ... khardt.pdf