pressure response on Airsense 11

dataq1 wrote: ↑

Wed Oct 20, 2021 7:35 pm

As a starting point can you answer a question I raised earlier, specifically, what are the units (Yaxis) of the the graph of Flow Limitation as reported by Resmed? (OSCAR's explanation of the Y axis of the Flow Limitations graph is "severity graded 0-1.0" )

I DID answer the question.

palerider wrote: ↑

Wed Oct 20, 2021 10:41 pm

I DID answer the question.

Sorry, I can not find your answer. Can you just restate the units of the Y axis on the flow limitation graph?

The other thing I don’t understand is: Why is the no similar graph (flow limitation versus time) on my Dreamstation Oscar report?

dataq1 wrote: ↑

Thu Oct 21, 2021 6:30 am

Sorry, I can not find your answer. Can you just restate the units of the Y axis on the flow limitation graph?

His answer:

palerider wrote: ↑

Tue Oct 19, 2021 11:25 pm

If you look at Resmed's software, the FL chart goes from 'rounded' at the bottom to 'flattened' at the top.

The numbers are just because that's what the graphing engine in Oscar shows.

Further reading on OSCAR FL chart.

http://www.apneaboard.com/wiki/index.ph ... imitations

Specifically on the y scale info

Resmed graphs flow limitations on a scale of 0 to 1

Philips flags flow limitations as events.

More info on FL in general and how they are measured.

http://www.apneaboard.com/wiki/index.ph ... limitation

http://www.apneaboard.com/wiki/index.ph ... _and_BiPAP

dataq1 wrote: ↑

Thu Oct 21, 2021 6:30 am

The other thing I don’t understand is: Why is the no similar graph (flow limitation versus time) on my Dreamstation Oscar report?

Because Philips Respironics machines don't report as much data.

dataq1 wrote: ↑

Thu Oct 21, 2021 6:30 am

palerider wrote: ↑

Wed Oct 20, 2021 10:41 pm

I DID answer the question.

Sorry, I can not find your answer. Can you just restate the units of the Y axis on the flow limitation graph?

No, this is turning out to be a waste of time.

palerider wrote: ↑

Thu Oct 21, 2021 12:20 pm

dataq1 wrote: ↑

Thu Oct 21, 2021 6:30 am

palerider wrote: ↑

Wed Oct 20, 2021 10:41 pm

I DID answer the question.

Sorry, I can not find your answer. Can you just restate the units of the Y axis on the flow limitation graph?

No, this is turning out to be a waste of time.

Many thanks for your gracious help.

GrumpyHere wrote: ↑

Thu Oct 21, 2021 7:18 am

Thank you so much, your post was extremely helpful. I'll spend some time studying the information you provided.

Pugsy wrote: ↑

Tue Oct 19, 2021 10:18 pm

ResMed has never really explained in much detail the whole flow limitation thing.
So I can't answer your questions. Sorry.
About all I have is this video.
https://www.youtube.com/watch?v=-gie2dhqP2c

In general snores and Flow Limitations are considered early signs of an impending airway collapse and the ResMed algorithm is designed to try to prevent the collapses so it is fairly aggressive in response to flow limitations but ResMed never really gave us the particulars in the algorithm....probably hidden in the patent somewhere but I am not going to go digging through the patents.

I am so sorry that you are having a difficult time composing and typing, perhaps one of the other board members can respond. But your reply here and articles that you pointed to have been pretty clear and succinct.

From the OSCAR article (and the Resmed video) the expectation for optimal sleep is a flowrate versus time graph that is sinusoidal smooth trace: while a flow limitation may present distortion such as: (You know all this already - but for completeness I've included it for others)

Now here is my flowrate v. time curve (observed with 5 cm pressure: I'd classify this as a flow limtation example, and in fact Resmed classifies it that way as well (because their/my flow limitation graph increases and initiates an incremental increase in pressure.

But here's the thing: I am sitting fully upright in a chair, fully awake and have no sense of distress (neither do I have any nasal congestion and of course no snoring).

So what is happening , because there is no reason to think that my airway is collapsing (no gravitation effect and BTW my weight is 210# BMI= 29) ????

dataq1 wrote: ↑

Fri Oct 22, 2021 4:13 pm

I'd classify this as a flow limtation example, and in fact Resmed classifies it that way as well (because their/my flow limitation graph increases and initiates an incremental increase in pressure.

But here's the thing: I am sitting fully upright in a chair, fully awake and have no sense of distress (neither do I have any nasal congestion and of course no snoring).

Sorry, I have no idea what is going on with your breaths. Above my pay grade.
Obviously not what we would usually consider normal morphology but while the machine might think it is "abnormal"....maybe for you it isn't abnormal since you were awake and all that. Maybe it is normal for you.
I know there is always a range of "normal" for pretty much everything.

Maybe a discussion with a doctor who really knows all the ins and outs with these breaths is in order if it bugs you.

These machines aren't perfect....nothing ever is and there are a lot of YMMV stickers out there.

Pugsy wrote: ↑

Fri Oct 22, 2021 6:17 pm

Sorry, I have no idea what is going on with your breaths. Above my pay grade.

And obviously above my pay grade as well !
But it leads me to wonder, suppose that my DME had outfitted me with a Respironics machine rather than the Resmed. I believe that the Deamstation makes no attempt at evaluating the shape of the flow rate v. time curve so doesn't produce a flow limitation "grade" that is used to incrementally increase the pressure. Am I correct in that understanding ????

I can try discussing this with my sleep doctor, however, based on comments he has made in the past, I'm unsure that would be useful as he does not seem to have a grasp on (nor perhaps an inclination) to do much besides write a CPAP therapy script. (Maybe I should ask him for the full report on the home sleep study)

Maybe my next step is to call my DME and ask if the Dr. had specified Resmed in his script. Then I can go back to the sleep Dr and ask for a reason (if he did specify Resmed) .

dataq1 wrote: ↑

Fri Oct 22, 2021 8:58 pm

I believe that the Deamstation makes no attempt at evaluating the shape of the flow rate v. time curve so doesn't produce a flow limitation "grade" that is used to incrementally increase the pressure. Am I correct in that understanding ????

Respironics machines have always done something with the FLs but again we aren't ever really told any in depth specifics as to how or why
BUT
Respironics machines will actually flag FLs and they show up on the events graph and you can easily see the actual breath that gets the flag.
So while flagged as a separate category of event...they aren't part of the AHI.

So ResMed does one thing with FL reporting (the graph thing) and Respironics does another thing (individual flagging). They both address what they think they are seeing though. They both will try to kill FLs and for me that's enough to know.

I have used both brands of machines over the years but I have never had much FL flagging show up from either brand so I really haven't dug deep into either. I don't expend a lot of energy on stuff that I don't see very often.