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[How to] To Marnid2014: How to Interpret your Leak Data
#1
To Marnid2014: How to Interpret your Leak Data
Marnid,

You sent me a zip file with the data from your S9 Elite. Just to help any other readers of this thread:

Your machine is an S9 Elite set to 8cm with EPR = 2. You are using a ramp that is 30 minutes long. You've been worried about leaks and have posted in this thread and this thread about your on-going adventures with leaks and with trying to get some meaningful help out of your DME and Resmed. You've also not been able to post any graphs of your daily leak data for us to see what's going on. And you're not sure what to look for anyway.

I'm starting this thread as a How To thread because I think it may serve as a decent tutorial for others about how to interpret leak graphs on an S9 machine.

To catch folks up: Marnid did post this image of the long term summary data from SleepyHead:
[Image: attachment.php?aid=781]
Marnid's long term leak numbers are:
  • Median Leak Rate = 4.04 L/min
  • 95% Leak Rate = 23.11 L/min
In this thread I explained that these leak numbers were not as bad as Marnid was afraid they were, but I also said that looking at the detailed leak rate data for some typical nights would be very useful for determining just how "bad" Marnid's leak problem actually is.

I've now loaded the data Marnid sent to me into SleepyHead and I have data for the last 5 days. In order to keep the posts themselves to reasonable lengths, what I want to do is create a post for each of the days and discuss that day by itself. And then I'll write some kind of a "concluding" post.
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#2
RE: To Marnid2014: How to Interpret your Leak Data
Ok, here we go with Marnid's data from 3-27:
[Image: Marni-3-27_zpsbd738df2.jpeg]
Let's start with the numbers in the left side bar:
  • Median Leak rate = 6.00
    95% Leak rate = 27.60
So for 50% of the night Marnid's leak rate was AT or BELOW 6.0 L/min, which is pretty good for someone fighting mouth leaking/breathing problems.

And for 95% of the night, Marnid's leak rate was AT or BELOW 27.6 L/min. That does mean that for 5% of the night Marnid's leak rate was AT or ABOVE 27.6 L/min, which is indeed large enough to be an Official Large Leak in Resmed-land.

So the numbers say we know that Marnid spent at least 5% of the night with leaks LARGE enough for the Resmed to have some problems compensating for the leaks. When we look at the leak line itself, we see that there are three areas circled in blue where the leak is clearly above the 24 L/min line for some time. There's also a leak that I forgot to circle where the leak is right at 24 L/min that occurs between 21:15 and 21:30.

Are leaks circled in blue mouth breathing? Maybe, maybe not. The leak rate is jumping UP and DOWN pretty rapidly. If this is mouth breathing, Marnid must be opening and closing her lips rather rapidly (he's taping her mouth, so we know the mouth is not gaping wide open). But it's also possible that she's moving moving around in some kind of a restless fashion that is jostling the mask back and forth. All of these leaks are LARGE enough to have a potential effect on therapy, but individually, the leaks are pretty short lived. The cluster of the leaks, however, is long enough to be a potential problem. A big question for Marnid on these leaks is: Did these leaks wake you up? Do you remember being restless during this part of the night?

The leaks that are not circled that occur between 20:15 and 21:30 are relatively LARGE and stable---they stay large for a long period of time. If Marnid hadn't said she's taping her mouth, I'd guess these are mouth breathing leaks. (Marnid: Did you tape on this night??) The first of these leaks, although it's long, is NOT large enough to really get worried about---the machine can compensate for leaks below 24 L/min and that first mouth leak is below that. The second one? It's potentially a problem.

But overall: The total time that Marnid spent in or very near Large Leak territory on this night was no more than 1.5 hours as I eyeball it. And the machine was running for just over 8.5 hours. So Marnid spent about 17.6% of the night in Large Leak territory. It's clear that Mr. Green Smiley showed up the next morning.

Now: Is 17.6% of the night in Large Leak territory enough to worry about? Maybe, maybe not. If those leaks are waking Marnid up, then she needs to worry about them. If she's not feeling particularly rested in the morning, she needs to worry about them. But in these cases, she needs to worry about them not so much because there is some leaking going on, but rather because the leaking may be the reason she's not sleeping particularly well. In other words, she needs to worry about the leaks in the larger context of how to make the mask and machine feel more comfortable at this point in her therapy.
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#3
RE: To Marnid2014: How to Interpret your Leak Data
Onto the night of 3-28. Here's the detailed data:
[Image: Marni-3-28_zps882da046.jpeg]
Again, let's start with the numbers:
  • Median Leak rate = 8.4
  • 95% Leak rate = 31.20
On this night, it's still clear that for at least 50% of the night, the leaks are under control since the median leak rate is 8.4. But the 95% leak rate = 31.2 by itself doesn't really tell the real story of how bad this night is.

Again a question for Marnid: Were you taping on this night?

There's one very short-lived leak (in RED) that's above 24 L/min. That leak (in the grand scheme of things) is not very important. But the leaks I've circled in BLUE are significant. They're both LARGE and (collectively) LONG. Except for the leaks at the very end of the night, they also look pretty much like mouth breathing leaks.

To Marnid: If you did tape this night, is it possible that you managed to get your lips open even if your jaw didn't drop open and then started breathing through the open lips?

Let's continue looking at those large leaks in the later half of the night: Much of the time between 0:30 and 3:30 is in Large Leak territory. During that three hour period, the leaks are AT or ABOVE 24 L/min for probably around a total of 120 minutes (2 hours) of that 3 hour time frame. So it is possible that the 5 events that are scored during this time maybe misclassified as CAs AND it's possible that the machine may have failed to score some events that happened during this time. The only way to check that out is to zoom in on the wave flow to see how ragged the breathing actually is.

The leaks at the very end of the night may or may not be mouth breathing. Again, if this is mouth breathing, Marnid's mouth is opening and shutting on a pretty regular basis. Or it could be tossing and turning jostling the mask.

The total time in Large Leaks on this night is pretty close to 2.5 to 3 hours as I eyeball it. And the machine was run for just over 9 hours. In other words, this is a night where (potentially) Mr Red Frowny may have shown up in the morning, since Mr. Frowny shows up when you spend 30% or more of the night with a Leak Rate AT or ABOVE 24 L/min, and 30% of 9:05 is 2:43, or just a bit less than 2.75 hours. So if the total Large Leak time is closer to 2.5 hours, Mr. Green Smiley showed up, but he just barely showed up. If the total Large Leak time is closer to 3 hours, then Mr Red Frowny should have showed up.

In other words, this is a good example of how bad the leaks have to be in order for the whole night to (barely) meet the criteria of a "Bad Night" in terms of the Resmed Engineers definition of "Bad Night".

If we zoom in on the wave flow and look at the individual breaths, it's also possible to find a specific example of how an official Large Leak can cause problems with the accuracy of the AHI data. Here's a super close up of the wave flow at around 3:06, when the leak rate is in the middle of one of those large leaks that we observed earlier:
[Image: Marni-3-28-closeup1_zpsc552080e.jpeg]
That part of the wave flow that I've circled in Red appears to be longer than 10 seconds, and hence it should have been flagged as an apnea. (As an aside, there's also a SH problem with drawing the 0 line in the wave flow correctly. This is a known problem for the unstable version of SH on the Mac; the problem is not that the wave flow is incorrect; the problem is that the graph is translated down too far relative to the horizontal 0.0 L/min line.)
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#4
RE: To Marnid2014: How to Interpret your Leak Data
And now we'll look at 3-29:
[Image: Marni-3-29_zps65e725ea.jpeg]
Again we start with the numbers:
  • Median Leak rate = 10.80
  • 95% leak rate = 37.20
The median leak rate is not as good as the previous two nights. And the 95% leak rate is also worse. Let's look at the leak line now: There are four distinct periods where the leaks are clearly above 24 L/min. The one I circled in Blue is likely mouth breathing or leaking. The red ones might be, but it's less clear. Again, if they're mouth leaks, the mouth is opening and closing pretty frequently.

The last set of leaks last for the last 1.5 hours of the night, but the leaks are NOT consistently above 24 L/min. To get a good estimate of the Total Large Leak time requires zooming in and scrolling through the whole night. When I do that I get a Total Large Leak time of about 150 minutes, or 2.5 hours. Since the machine was run for about 8.5 hours, the percent of time spent in Large Leak territory is about 2.5/8.5 = 29%, so again this right around the cutoff line between where Mr. Red Frowny shows up and where Mr. Green Smiley shows up.

Looking at the wave flow during some of the high leak periods shows other potential problems the machine has in tracking the AHI data. Here's a place where there are several possibly "missed" hypopneas:
[Image: Marni-3-29-closeup3_zpscfd8f4a6.jpeg]
Also notice that the size of the inhalations and exhalations is rather small, and that may be because the machine is simply having trouble detecting the actual airflow into/out of the lungs. And that itself makes it more difficult for the machine to determine when a hypopnea or apnea occurs


Total time in large leaks appears to be about
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#5
RE: To Marnid2014: How to Interpret your Leak Data
And onto 3-30:
[Image: Marni-3-30_zpsa866d8c4.jpeg]
The numbers don't seem all that much different from the previous nights:
  • Median leak = 8.4 L/min
  • 95% Leak = 30.00 L/min
But visually this night seems a bit better: There is only one prolonged period of leaking above 24 L/min plus some minor peaks of leaking above 24 L/min now and then. The LONG and LARGE leaks circled in Blue appear to be some prolonged mouth leaking.

The total time in Large Leaks on this night seems to be about 135 minutes, or 2.25 hours and the run time is 8.78 hours (8:47 is 8.78 hours since 47 minutes = .78 hours). So the percentage of time in Large Leak on this night is about 25.7%.

So the problem on this night is the one very long prolonged period of Large Leaks.
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#6
RE: To Marnid2014: How to Interpret your Leak Data
Finally we arrive at 3-31:
[Image: Marni-3-31_zps94ad622f.jpeg]
The numbers are:
  • Median 0.0 L/min (YEA!!)
  • 95% 20.4 L/min (YEA!!)
  • Maximum 24.0 L/Min (YEA!!)
These numbers indicate that the amount of time in Large Leak was very small: You were leaking AT or ABOVE 24 L/min for no more than 5% of the night, and since the Maximum leak rate is 24.0, you were NOT leaking ABOVE 24 L/min during the night for any measurable amount of time.

If you look at the leak line for this night there are a few places where the leak line pokes above 24 L/min. There's still some evidence of potential mouth leaks/breathing off and on, but none of them are LARGE enough to really matter.

If you can get your leak line to look like THIS one on MOST nights, then you can safely conclude that your leaks are sufficiently under control that you don't need to worry about them unless they're waking you up or clearly disrupting your sleep.
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#7
RE: To Marnid2014: How to Interpret your Leak Data
Final conclusion:

To Marnid: There is some evidence that you have some mouth leaking or mouth breathing going on. The taping may be bringing it under control---that last night looks much better than the previous four nights. But even on the worst of the four nights you are right at the edge of where Resmed declares that Large Leaks are both LONG enough and LARGE enough to be a real problem.

In other words, while there's a lot of room for improvement in terms of leaks, your leaks are NOT total disasters either. On even your worst nights, your leaks are well controlled for over 50% of the night and are decently under control for somewhere around 70-80% of the night. That means that on your worst nights, you are flirting with nasty leaks in terms of what Resmed defines as "nasty leaks". The downside of that is obvious: Sometimes your leaks probably ARE both long enough and large enough to adversely affect your therapy. But the upside of this is this: You need some MODEST improvements in your leaks to get your leaks into a range where they really are acceptable in terms of therapy.

So what to do?

Well the first thing is to think about this: What (if anything) was different about the night of March 31? If you did something different on 3-31, then it's worth repeating the experiment.

You say you've been taping---how many nights have you taped? If you taped on all these nights, then it could be that you're finally figuring out how to tape effectively. Like everything else with PAP, taping takes practice to get it right.

Or it could be that with the tape, your mouth and lips are finally beginning to stay more snuggly shut when you're asleep and that when air gets into your mouth, it's no longer causing you to open your lips enough cause really Large Leaks.

What to do next? Watch those leak lines for a while. If you start seeing a lot more lines that look like the one from 3-27 and (especially) 3-31 and fewer of the ones that look like 3-28 and 3-29, then you know the leaks are trending in the correct direction. On the other hand if you start to see a lot of nights like 3-28 and 3-29, then you know that you're going to need to work on the leaks more diligently.

In other words, it's worth seeing if your leaks start to settle down in the next week or so. But if you continue to have nights with multiple periods of prolonged leaking at or above the 24 L/min level in the next couple of weeks, then it may be time to be thinking about whether you need a chinstrap instead of or in addition to the taping. Or whether you need to consider a full face mask.

Good luck with nailing down how to minimize the leaking.
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#8
RE: To Marnid2014: How to Interpret your Leak Data
First, THANK YOU, I hope this will help others to read their stats as well. I know that it's so hard to interpret this data and I thank you again for doing this, hopefully this will answer questions for people.

The last night, you read 3/31, I went back to my old mask, the Swift FX for her. I taped very well and slept good. I was trying to use the P10 the other nights, so it looks as if that might not be the mask for me, even though I like it. I can deal with the FX.

They gave me a new mask and I used it last night, I was up most of the night as it was hitting my eyes and very uncomfortable. It was the nano. It is way too big for me and this morning my numbers look similar to the worse ones you have mentioned, so I believe that is certainly not the mask for me. I have tried the full face and am too claustrophobic to wear it. I claw at it at night, and even during the sleep study.

One question I have for you, if you can. In February, my pressure was down to 6, and looking at the numbers and the same FX mask that I was wearing on 3/31, I can see those leaks are VERY small for the period of Feb 13 through 26th, and then after they raised my pressure for an experiment, my leak rate went up and stay's up while experimenting with new masks.

I see, unless I am missing something that the less pressure caused me to have less leaking and better AHI while wearing the same FX mask that I wore again on 3/31. Can you comment? I was thinking of asking my DME to lower my pressure to 6 again with wearing the same mask, the FX that I was wearing then and see if the same results can be duplicated. My doctor has given permission to use the numbers from 6 to 12 for pressure. What do you think? Could any of this be due to too much pressure???? Would you try going back to 6 if you were me?

I would lower it myself but my DME won't allow it. I am not sure if I should just go for it and do it on my own, I hate the fact that they charge for each visit to medicare, I don't want to be part of the problem of health care costs sky rocketing just for a simple change that has already been ok'd by my doctor.
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#9
RE: To Marnid2014: How to Interpret your Leak Data
(04-02-2014, 09:00 AM)Marnid2014 Wrote: First, THANK YOU, I hope this will help others to read their stats as well. I know that it's so hard to interpret this data and I thank you again for doing this, hopefully this will answer questions for people.

The last night, you read 3/31, I went back to my old mask, the Swift FX for her. I taped very well and slept good. I was trying to use the P10 the other nights, so it looks as if that might not be the mask for me, even though I like it. I can deal with the FX.
It does look like the Swift FX may be a better mask for you than the AirFit P10. Perhaps it's because the FX has adjustable headstraps. I'm trialling the AirFit as well, but the Swift FX has been my go to mask for 3 1/2 years. It's a good mask.

Quote:They gave me a new mask and I used it last night, I was up most of the night as it was hitting my eyes and very uncomfortable. It was the nano.
What cushion size???

Quote: I have tried the full face and am too claustrophobic to wear it. I claw at it at night, and even during the sleep study.
This is a good reason to try to make the Swift FX work.

Quote:One question I have for you, if you can. In February, my pressure was down to 6, and looking at the numbers and the same FX mask that I was wearing on 3/31, I can see those leaks are VERY small for the period of Feb 13 through 26th, and then after they raised my pressure for an experiment, my leak rate went up and stay's up while experimenting with new masks.

I see, unless I am missing something that the less pressure caused me to have less leaking and better AHI while wearing the same FX mask that I wore again on 3/31. Can you comment?
In general all masks are easier to seal at lower pressures than higher ones. There's just less air trying to blow the mask off your face to contend with.

And that brings up an interesting idea: Are you fitting your mask at the beginning of the ramp with your low starting ramp pressure? And then as the pressure builds up, you start to have problems? You might try turning the ramp OFF to fit the mask while you're awake, but lying down in your normal sleep position. See if you need to tighten the straps a wee bit or whether the mask seems to be more sensitive to jostling. If so, then you know you need to work on figuring out a way to fit the mask at full pressure and then turn the ramp on if need be. (This is easy on a System One, but I'm not sure how to do it on an S9)

Quote:I was thinking of asking my DME to lower my pressure to 6 again with wearing the same mask, the FX that I was wearing then and see if the same results can be duplicated. My doctor has given permission to use the numbers from 6 to 12 for pressure. What do you think? Could any of this be due to too much pressure???? Would you try going back to 6 if you were me?
What did the AHI look like at 6cm??

Quote:I would lower it myself but my DME won't allow it. I am not sure if I should just go for it and do it on my own, I hate the fact that they charge for each visit to medicare, I don't want to be part of the problem of health care costs sky rocketing just for a simple change that has already been ok'd by my doctor.
Me? Since the doc has given you permission to play with the pressure a bit, I'd just do it and not bother with the DME. Yeah, if you have to return the card for a Medicare compliance check you'll get a thorough lashing with a wet noodle, but nothing else.

Here's an idea:
Reset the pressure at 6cm for a WEEK and see what happens if you use the FX and taping. Look at both LEAKS and AHI.

If the AHI remains under 5.0 at 6cm AND the leaks are under control, you have your answer.

If the AHI creeps up too high, but the leaks are under control, then bump the pressure up by 0.5cm and leave it there a week. Again track both Leaks and AHI.

Keep repeating this process until you manage to find a pressure where: (1) The AHI is below 5.0 for the entire week and (2) the leaks are no worse than they were on 3-31. Once you have that pressure identified, stick with it for at least a month to evaluate how you're feeling. And once you have that pressure identified if you want to start experimenting with the AirFit P10 mask again, you may have a better trained mouth and things might go a bit better---if you can find a position for the straps that keeps the pillows properly in place with that small head of yours.
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#10
RE: To Marnid2014: How to Interpret your Leak Data
Here are those numbers


These are all using the FX for her and pressure 6. When they upped the pressure, my leaks increased.

2/13 PRESSURE 6
MIN 0.00
MED 1.20
95% 4.80
MAX 10.80
AHI 1.47

2/14
MIN 0.00
MED 1.20
95% 10.80
MAX 13.20
AHI 1.21

2/15
MIN 0.00
MED 1.20
95% 4.80
MAX 13.20
AHI 0.36

2/16
MIN 0.00
MED 1.20
95% 7.20
MAX 9.60
AHI 0.78

2/17
MIN 0.00
MED 1.20
95% 7.20
MAX 10.80
AHI 0.95

2/18
MIN 0.00
MED 2.40
95% 8.40
MAX 9.60
AHI 0.72

2/19
MIN 0.00
MED 1.20
95% 10.80
MAX 14.40
AHI 0.81

2/20
MIN 0.00
MED 1.20
95% 10.80
MAX 13.20
AHI 0.72


2/21
MIN 0.00
MED 1.20
95% 12.00
MAX 16.80
AHI 1.98

2/22
MIN 0.00
MED 4.80
95% 20.40
MAX 25.20
AHI 0.20

This all continues pretty much the same, goes up a little and down, however I was getting pneumonia and my sleep time was less for awhile.

Then they changed my pressure to 8 and everything went up from there.



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