S9 Flow Limitation Graph -- Questions

[SleepingUgly]

Anyone have any clue how to interpret the S9 Flow Limitation Graph? How can I tell how extreme my FLs were each day? Wish there was a numerical index like on the PR System 1...

[idamtnboy]

Anyone have any clue how to interpret the S9 Flow Limitation Graph? How can I tell how extreme my FLs were each day? Wish there was a numerical index like on the PR System 1...

Check out this thread. Maybe you'll find your answer there. viewtopic/t57594/viewtopic.php?f=1&t=57 ... 72#p540472
There actually is a variable number for FL in the data, but I haven't tried to intrepret its meaning as shown in Resscan.

[SleepingUgly]

Anyone have any clue how to interpret the S9 Flow Limitation Graph? How can I tell how extreme my FLs were each day? Wish there was a numerical index like on the PR System 1...

Check out this thread. Maybe you'll find your answer there. viewtopic/t57594/viewtopic.php?f=1&t=57 ... 72#p540472
There actually is a variable number for FL in the data, but I haven't tried to intrepret its meaning as shown in Resscan.

I saw that thread after I posted. Ooops. What do you mean there is a number? Where do you see it?

[idamtnboy]

Anyone have any clue how to interpret the S9 Flow Limitation Graph? How can I tell how extreme my FLs were each day? Wish there was a numerical index like on the PR System 1...

Check out this thread. Maybe you'll find your answer there. viewtopic/t57594/viewtopic.php?f=1&t=57 ... 72#p540472
There actually is a variable number for FL in the data, but I haven't tried to intrepret its meaning as shown in Resscan.

I saw that thread after I posted. Ooops. What do you mean there is a number? Where do you see it?

Mouse over the graph line. The value at that point is shown in a little pop up box.

[SleepingUgly]

Mouse over the graph line. The value at that point is shown in a little pop up box.

Yeah, I don't know what that number tells me.

[jerainey]

Thanks idamtnboy. Now that I see a number I'm happy. I guess it's the ol' retired engineer in me. When I looked at a 0.17 Flow Limitation I could see clearly what ResScan was seeing in my flow trace that produced the FL. The inspiring portion for the matching point had a dip and a rise much different from the normal pattern. No tendency toward an apnea, however. I can now lay to rest my concerns over FL and figure out something else to worry about; like learning enough about doing Windows on my Fusion iMac app to show you the wave form that I found thanks to your help.

[idamtnboy]

Mouse over the graph line. The value at that point is shown in a little pop up box.

Yeah, I don't know what that number tells me.

Best I can figure out is 1 is wide open airway, and 0 is a partially closed airway. How partially, Resmed doesn't say. Here again is what's in their lit.
"Flow Limitation - Flow Limitation is a measure of partial upper airway obstruction. This measure is based on the shape of the inspiratory flow–time curve. A flat shape suggests upper airway obstruction."

I think it's intended to give the reviewer an idea about how much the person's airway is closing down during the inhalation process. Is Flow Limitation a Resmed only term, or a medical community term, I do not know. The best thing I can suggest at this point is to look at the flow graph at the same time as a FL line goes away from full open, or 1, and see if you can tell a difference from when the FL is 1.

The inspiratory flow–time curve is the flow graph when you inhale. The flow graph shows how fast air is moving into or out of your lungs, measured 25 times a second. Think about how you breathe. For a moment you have no air moving in or out. Then you start to breathe. Air starts moving in faster and faster, and then it peaks, and then slower and slower until your lung is full. Air is moving slow at the start and end of the inhale phase. That's the zero line on the flow graph. Then the process is repeated as you exhale. When you look at the flow graph all of the line above zero shows how fast air is moving in. All of the line below zero shows how fast air is moving out. Contrary to what one may be inclined to think the rising line from the bottom below zero to the top above zero is not the inhale segment of the graph and the falling line is not the exhale segment. I'm an engineer and I still had to stop and think hard about this to get it clear in my mind!

Does this help you out any more?

[NotMuffy]

Best I can figure out is 1 is wide open airway, and 0 is a partially closed airway.

Well I must admit to being completely flummoxed (17 matches)(whoops! 18!).

While everyone on the planet (including, for that matter, Michael Berthon-Jones) says that's the case (although in practice a "wide-open airway" should have a value of about 0.3), ResScan says the higher the value, the worse the flow limitation.

NM

[SleepingUgly]

While everyone on the planet (including, for that matter, Michael Berthon-Jones) says that's the case (although in practice a "wide-open airway" should have a value of about 0.3), ResScan says the higher the value, the worse the flow limitation.

Everyone says what's the case?

Bottom line, how can I tell how severe my flow limitations are?

[idamtnboy]

ResScan says the higher the value, the worse the flow limitation.

No, it's the other way. 1.0 is wide open, 0, or close to it, is closed. The graph in ver 3.11 is upside down with open at the top. They flipped it in ver 12.

Bottom line, how can I tell how severe my flow limitations are?

Quite possibly, you can't. I think the best you can decipher from the numbers and the graph is the fact that your airway is more restricted when the graph line is close to the flat symbol than it is when it is closer to the hump symbol. When I look at my graphs I really do not see a definable correlation between the FL number and either the flow graph or the event graph. At this point I have no idea what it's value is for diagnostic purposes. I just looked at several of my graphs. It appears that every time I had an OSA, which isn't very often, the FL number is 1.0 meaning the upper airway passage was wide open. So, as a practical matter what does the FL number tell me? Nothing!

[SleepingUgly]

No, it's the other way. 1.0 is wide open, 0, or close to it, is closed. The graph in ver 3.11 is upside down with open at the top. They flipped it in ver 12.

Which way is it in version 3.10, which is what I have?

[NotMuffy]

ResScan says the higher the value, the worse the flow limitation.

No, it's the other way. 1.0 is wide open, 0, or close to it, is closed. The graph in ver 3.11 is upside down with open at the top. They flipped it in ver 12.

I believe it is a combination of factors. If you take a pre-S9 machine and read the DL in 3.12, you'll see the old parameter "Flattening Index", and "normal" is at the top, so "Flow Limitation" seems to be more a function of machine vs software.

[NotMuffy]

They flipped it in ver 12.

I don't think they "flipped it"-- I think they just screwed it up.

[idamtnboy]

No, it's the other way. 1.0 is wide open, 0, or close to it, is closed. The graph in ver 3.11 is upside down with open at the top. They flipped it in ver 12.

Which way is it in version 3.10, which is what I have?

Don't know since I've never seen or used 3.10, but I would guess the same as in 11. The hump, or beehive, shape symbol is at the top which is the fully open symbol. The value is 1.0. Fully closed, the flat symbol, with value of 0.0, I think, is at the bottom. In any case look at the symbols at the left edge of the graph. The symbols mean the same in 11 and 12. It's just that they swapped which way the graph is drawn.

[SleepingUgly]

But when I run my mouse cursor over those scribbles, it could say 1.00 whether I'm above the top line at the "beehive" or 3 lines below that top line... In fact, I don't see a spot that makes my cursor say 0.