definition of flow limitation

[jnk]

They give us access to the information. If they have a paper for docs on how to use the information, it will eventually show up on the Internet. I am unaware of any such paper.

As to how medically to use FL info from home-treatment machines, docs don't agree. That's not where they get diagnostic info, anyway. There are docs who will treat arousals from events that are less than hypopneas. Those docs are on the cutting edge and not part of the mainstream yet, in my opinion.

I don't blame any patients for getting any info for trying to improve how they feel. But I don't blame companies for allowing their home machines to provide data that can be used as any doc, or patient, sees fit, as far as that goes.

To me, the only understanding needed for home-machine reported data is that you get it as low as you can but not lower. You try things. Many things. But only if your sleep is bad. And FLs don't prove sleep is bad. If someone leans toward UARS, anything that helps stabilize the airway is useful for keeping it stable. What accomplishes that is different for each user.

ResMed's full-data machines report the data, and ResMed has allowed ResScan out of the bag where anyone can get to it, along with instructions on how to use it. I applaud that. I don't trust ResMed any more than any other company, but I appreciate their efforts to give info to patients. I hate it that the S9s don't report as much info from the screen as the S8s did. I miss that. But the info allowed from the SD card helps to make up for that inconvenience, I guess.

I don't think ResMed is any more knowledgeable than anyone else when it comes to the meaning of the FL data their machines report, though. ResMed allows the data to be seen. That is enough for me. I don't look to the machine manufacturer to tell me how to use that info for choices involving overall treatment decisions. But hey, that's just me.

That said, I hope all patients get what they need to make their treatment as good as it can be. Just remember that perfectly normal, healthy, non-SDB people don't breathe perfectly either. All humans have apneas, hypopneas, and flow limitations. Those are events that can be tracked and noted but not diseases in and of themselves unless there is proof they are fitting a pattern of regularly, unduly disturbing the sleep of a particular patient.

In my opinion. Which ain't any more valuable than anyone else's, of course.

[avi123]

Papit if you have got this machine, then, IMO, if it set correctly, it should have treated all of your Flow Limitations and we should not see any FL events left over in the graph. Al those spikes in your FL graph should have gone. Am I correct?




The following taken from the same source show how the machine does it:








Notice the wording in this explanation:

In ASVAuto mode, the EPAP also responds to flow limitation, snore
and obstructive apneas on the next breath, in proportion to the
severity of the event.

It also means that if you set the EPAP correctly it would eliminate any tracings in the FL graph data. You would see it empty. In such a case don't try to show FL graph at LOW SPEED, as I mentioned to you before, b/c there will be none. Which is GOOD!

[jnk]

. . . should have treated all of your Flow Limitations . . .

In my opinion, for many patients, immediately bludgeoning every minor FL over the head would be highly unlikely to improve sleep. FLs are often something for the machine to react to, to respond to, sure. But many patients will never have perfectly shaped flow curves no matter what they do. So a report of some FLs is not an indication of failed treatment.

Improving the shape of a flow curve is a nice thing to do when possible. But there are comfort reasons for not trying to make every breath absolutely perfect. There is a law of diminishing returns that can easily get flipped to negative returns. It would defeat the purpose of sleep-improvement machines to destroy sleep in an attempt to make breathing perfect.

For some people, using a treatment pressure that is a few cm above what gets rid of hypopneas and apneas can be a good thing:

4.2.2.6 “Exploration” of CPAP above the pressure at which control of abnormalities in respiratory parameters is achieved should not exceed 5 cm H2O (Consensus).
This recommendation is based on consensus agreement by the PAP Titration Task Force. CPAP exploration does have utility; upper airway resistance can be four times normal despite selection of a pressure that eliminates apneas and hypopneas, and this residual high airway resistance can lead to repetitive arousals and insomnia. Reduction of this resistance has been demonstrated by increasing pressure until esophageal pressure swings (if measured) or the shape of the inspiratory flow limitation curve are normalized, or by increasing pressure by 2 cm H2O but no higher than by 5 cm H2O.--http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2335396/

However, making an APAP algorithm that rides 5 cm higher than what many need to normalize sleep could destroy the sleep of the people who do not need that extra 5 cm of pressure to get good sleep.

In my opinion as nothing more than a patient.

[jnk]

. . . It also means that if you set the EPAP correctly it would eliminate any tracings in the FL graph data. . . .

As I understand it, that could be true for some people. But I do not believe it to be true for all. Many would be unable to tolerate the high pressure necessary to accomplish that goal, even if possibly worthwhile for some individuals.

So if you let the machine choose your EPAP, it is going to do so based on the largest part of the bell curve of the target population--not based on an individual need for pressures higher than what is needed to eliminate most significant obstructive events for most people.

And that is true even in the context of the ResMed S9 VPAP Adapt.

Maybe one day auto-titrating machines will be customizable to the point that you can push a button on the machine that says "keep EPAP/IPAP/CPAP 2 cm above what you think I need according to your algorithm." And maybe one day autos will be able to sense indications of impending flow limitations. I do not believe that day has yet arrived.

I wish -SWS were here to explain all this better.

[avi123]

jnk, are you using this machine to state this:

And that is true even in the context of the ResMed S9 VPAP Adapt.

I am looking for a response from Papit, or from those who are using this machine.

Your postings with too many "can"; "maybe"; "most likely", "possibly", etc., can't convince me, while Pepit and others are waiting.

[jnk]

jnk, are you using this machine to state this:

And that is true even in the context of the ResMed S9 VPAP Adapt.

I am looking for a response from Papit, or from those who are using this machine.

Your postings have to many "can"; "maybe"; "most likely", "possibly", etc., to convince me

1. Your postings don't have enough of such words to convince me, since, in my opinion you can maybe most likely possibly often tend to state your own opinion as verified facts that need no qualifications whatsoever.
2. I would never attempt to convince you of anything, trust me. I have repeatedly seen the futility of others' attempts to convince you of anything that runs contrary to your opinions.
3. I apologize for cluttering up your thread. Oh. Wait. Nevermind.

I'm just glad there's someone on this board older and grumpier and more opinionated than me today.

[avi123]

Jeff, why don't you summon -SWS in here to solve this issue of FL? Papit and others are anxious to find out about it. Do you actually expect Papit's Doctor to solve this FL problem for him? We need to know if the ResMed S9 VPAP Adapt is capable to eliminate FL. Yes or no.

I'm just glad there's someone on this board older and grumpier and more opinionated than me today. are you also referring to Iran, Hisbolla, and Syria
saying that they will attack Israel if the U. S. will bomb the chemical storage in Syria? Do I need to be less grumpy b/c of it?

[jnk]

* sticks fingers in own ears *

La la la. I can't hear you. I'm not listening. La la la.

[Papit]

Papit, can you show a section of your Flow Limitation graph in LOW SPEED?

Sure thing, but it's ugly. I'm posting below five 1-minute scale images taken at different times, some when strong FL's occurred and some when they did not occur at all. Lots of nice rounded tops are seen in the flow, not too many "chair" shapes, but plenty of wave form irregularity all over the place. Notice too the very frequent rapid gyrations in both Pressure and Flow in the 5-hour graphs. At the bottom is the Statistics page for the sleep session (0.1 AI, 1.1 AHI). Have a "ball," avi ! Most people's Flow that I've seen posted here settle down for sustained periods, but not mine.

[avi123]

* sticks fingers in own ears *

La la la. I can't hear you. I'm not listening. La la la.

If you played it on your guitar it might have sounded like this:

https://www.youtube.com/watch?v=HYzx556Rp5Q

who knows?

[avi123]

Papit, if in 5 hours you got only these for FL then it looks NOT BAD, I think,(for Jeff).




If I compare your FL graph to my 10 hours graph then I see that your FL amplitudes are much higher but its frequency is much less.



Who knows if playing with your EPAP pressure could lower the FL on the S9 VPAP Adapt?




P.s. if you're a Selnik then we might be related.

[avi123]

Papit, on what mode was the S9 VPAP Adapt set when you took the above graphs?

From the following two graphs I can see that you had about 30 FL events during the 5 hours.

Your respiration rate counts to about 12 per min which is normal.

Many of the respiration waves have flat tops (not sinusoidal), manifesting FL.

Do you have any anatomical malformation in your nose or mouth to cause this FL, such as deviated septum, large tonsils?

The nasal pillows mask could also cause FL. Do you have another type of mask for a trial?





I am wondering if you change the VPAP reporting by doing this:


Here are instructions (edited) for adding the Flow Limitation graph to your Detailed Graphs and Reports. I'm looking for users of the ResMed S9 VPAP Adapt and Respironics BiPAP Auto SV to see how common (because of a software artifact) or how patient-specific (therefore varying) are the occurrence of frequent and strong graphed FL spikes. My FL graph during the 18 months I used cpap and apap showed relatively few, very weak flow limitation 'events'. On my new ASV, S9 Vpap Adapt, the graph shows tons of strong and medium ones. Are you seeing the same on your S9 Adapt or BiPAP Auto SV machine? How about when you were using a cpap or apap?

To view your Flow Limitation graph, open your patient account in ResScan as usual and then select the REPORT menu. Then click the CUSTOMIZE tab. Expand the Detailed Graphs by clicking the “ (+) ” next to it on the right side of the page (under Report Layout). Then do the same on the left side of the page (under Available Items). Now select Flow Limitation and click “Add”. And then click OK.
---- OR ----
To view your Flow Limitation graph in SleepyHead, open SH, click the File menu and select Preferences. Then select the Graphs tab, check the box next to “Flow Limit” in both the upper “Daily Graphs” list and further below in the “Overview Graphs” list. Then click OK and you will have added the Flow Limitation graph to the other graphs you can see.

[Papit]

Avi, see my replies embedded below:

Papit, on what mode was the S9 VPAP Adapt set when you took the above graphs? [Regular ASV mode, not the AutoASV mode]
From the following two graphs I can see that you had about 30 FL events during the 5 hours. [Yep, actually more are seen when I zoom in on the bold spikes. And most are strong/maximum height. During the preceding year with the S9 AutoSet, I hardly had any flow limitations and those I had were very weak.
Your respiration rate counts to about 12 per min which is normal.
Many of the respiration waves have flat tops (not sinusoidal), manifesting FL.
Do you have any anatomical malformation in your nose or mouth to cause this FL, such as deviated septum, large tonsils? [I think my septum is ok. My tonsils were removed as a child. An ENT saw nothing. My lungs recently tested good. No emphazima or asthma. No allergies either.]
The nasal pillows mask could also cause FL. Do you have another type of mask for a trial? [Good idea. I'll try a FFM tonight and let you know tomorrow.] Thanks.

[avi123]

Papit, check this thread:

viewtopic/t62947/Help-Clueless-about-Fl ... tions.html

Notice there this FL graph from S9 VPAP Adapt:

[avi123]

You could check Resmed's method of reporting FL in the graph:

http://www.sumobrain.com/patents/wipo/A ... 8040A1.pdf

see illustrations in the back