Please Help Me Interpret my Stats

[MJS_]

Since I am too early in my CPAP journey to know what I need, knowing how far my results deviate from what is normal may help me make informed decisions.

I don't understand how.

Then again, I don't *need* to understand how you think it's going to help you.

If I were to learn that my flow restriction stats were about 1 standard deviation above the mean for my gender and age group (i.e., above average but not extreme) and that the health consequences associated with this level of flow restriction were mild, I might increase my Min/Max pressures by a small amount. OTOH, if I learned that my flow restrictions stats were 2+ standard deviations above the mean (i.e., extremely elevated) and the health risks were severe, I would increase my Min/Max pressure by greater amounts.

[palerider]

Since I am too early in my CPAP journey to know what I need, knowing how far my results deviate from what is normal may help me make informed decisions.

I don't understand how.

Then again, I don't *need* to understand how you think it's going to help you.

If I were to learn that my flow restriction stats were about 1 standard deviation above the mean for my gender and age group (i.e., above average but not extreme) and that the health consequences associated with this level of flow restriction were mild, I might increase my Min/Max pressures by a small amount. OTOH, if I learned that my flow restrictions stats were 2+ standard deviations above the mean (i.e., extremely elevated) and the health risks were severe, I would increase my Min/Max pressure by greater amounts.

Alternatively, you just increase your min pressure until your pressure chart is relatively smooth and breathing issues aren't waking you up at night.

Statistics have nothing to do with that.

[ozij]

I'd still like to learn how far (or how many SD's for those who are math professors ) my Flow Limitation statistics are from the average,

Which does you absolutely nothing to help you optimize your therapy.

A couple points.... Diagnostic tests in the fields of psychology and medicine (including sleep disorders) generally rely on the concept of how much an individual's results vary from the mean, median, or "normal" range. Also, pretty much any medical or physical intervention that alters how our bodies function has the potential for negative side effects. It is possible that increasing CPAP air pressure until all flow limitations are eliminated could have negative side effects that outweigh the benefits.

You need youwhat YOU need....

Since I am too early in my CPAP journey to know what I need, knowing how far my results deviate from what is normal may help me make informed decisions.

@MJS
Your are confusing descriptive statistics, which describe populations, with the need to focus on a single case - you own. From the point of view of descriptive statistics, the probability of a single case is zero. That is, you with you singular needs do not even exist as far as descriptive statistics are concerned.sp

What you have to discover in order to optimize your therapy is how your singular body responds to the specific machine settings.

Some of us can, and should raise pressure enough to make flow limitations disappear, other's cannot and should not. The "others" are a minority, but the only way of learning where you sit in the distribution is by trial and error, on your single case.

The information you need for your informed decision is what happens to you when you make changes in your setting.

What we are telling you is: Look at you own results.

You results show the following:
Flow limitations are driving your machines as high as you're letting it go.
Flow limitation are pushing your machine away for the minimum within an extremely short time - no need for you to be there at all. Though, since the machine is responding so quickly it doesn't really matter if your minimum is 5 or more

If I were to learn that my flow restriction stats were about 1 standard deviation above the mean for my gender and age group (i.e., above average but not extreme) and that the health consequences associated with this level of flow restriction were mild, I might increase my Min/Max pressures by a small amount. OTOH, if I learned that my flow restrictions stats were 2+ standard deviations above the mean (i.e., extremely elevated) and the health risks were severe, I would increase my Min/Max pressure by greater amounts.

No.
The speed at which you change your pressure settings depends on how your body adapts to the change.
If you were training to be a weightlifter, and learned you were starting at 2 STD below where you want to be, you would not (should not) choose heavier weights to train with just because your are so far away from your target weight.

Forget the population and focus on your own results, and how you feel in response to changes you make.

[MJS_]

Alternatively, you just increase your min pressure until your pressure chart is relatively smooth and breathing issues aren't waking you up at night.

Statistics have nothing to do with that.

That would be good advice if...

1) breathing issues were waking me up at night. To the best of my knowledge, they have not. Even when my apnea was more severe and untreated, I would rarely wake up after fully falling asleep except to urinate due to BPH [I'd also feel okay in the morning, but then become overwhelmingly sleepy 8 or 10 or 12 hours later.]

2) My flow limitations with CPAP are caused by my MIN pressure setting being too low, not my MAX pressure setting.

3) My degree of flow limitations pose a significant risk to my health. [I do not know whether they do.]

4) There is little to no chance that raising my pressure until the flow limitations disappear cause side effects that outweigh the benefit. [I do not know whether this is true.]

[palerider]

1) breathing issues were waking me up at night. To the best of my knowledge, they have not.

If people *remembered* being waked up several hundred times in the span of a nights sleep, there'd be much less need for sleep tests to find out if people had sleep apnea.

2) My flow limitations with CPAP are caused by my MIN pressure setting being too low, not my MAX pressure setting.[/quote]
I don't think I said anything about MAX settings, so why bring it up? for the vast majority of people, the MAX setting should be left at whatever the machine's maximum possible is.

3) My degree of flow limitations pose a significant risk to my health. [I do not know whether they do.]

What is "significant"? do you ignore things that are only partially 'significant'?

4) There is little to no chance that raising my pressure until the flow limitations disappear cause side effects that outweigh the benefit. [I do not know whether this is true.]

One should look at *YOUR* data, not my data, not ozij's data, not Robysue's data to see answers.

[MJS_]

@MJS
Your are confusing descriptive statistics, which describe populations, with the need to focus on a single case - you own. From the point of view of descriptive statistics, the probability of a single case is zero. That is, you with you singular needs do not even exist as far as descriptive statistics are concerned.sp

Actually, statistics CAN describe a single case. I'd like to compare the statistics which describe a single case (me) with statistics that describe a population to which I belong. This is a standard method of medical and psychological diagnosis which can help inform treatment decisions.

Some of us can, and should raise pressure enough to make flow limitations disappear, other's cannot and should not.

I suspected this might be the case, but I did not know. When I don't know stuff, I like to proceed cautiously.

The "others" are a minority, but the only way of learning where you sit in the distribution is by trial and error, on your single case.

I am well versed in the scientific principles of experimentation to test hypotheses. In order to attribute an observed change to your hypothesized cause, other potential explanations need to be ruled out via experimental design (e.g., random assignment to an experimental or control groups in which confounding variables are equalized) or in this case, a quasi-experimental design in which a baseline level of therapy efficacy is measured while keeping all relevant variables constant before changing the one variable (e.g., Max air pressure) that you hypothesize will cause improvement. It is very common for people to mistakenly attribute observed changes to their suspected cause while failing to consider alternative explanations.

Currently, I am in the process of adjusting to new face masks, new CPAP machine, new air hose temperature, new humidity settings, new ramp settings, new EPR settings, new pressure settings, etc. Therefore, this is not a good time for me to attempt to draw conclusions based on trial and error. At such times, it can be helpful to utilize generalized knowledge and statistical comparisons to relevant populations to inform treatment decisions.

It is quite possible that you and others have generalized knowledge about this field that I lack, and if I knew what you all knew then I would not hesitate to follow your advice to jack up my Min air pressure or Max air pressure or both. However, I've become very wary of "common knowledge" in the medical field which is often be based more on profit incentives or traditional beliefs or trendy narratives than on science. Therefore, I often will explore the reasoning and evidence behind a recommendation rather than just blindly following it.

[ozij]

@MJS
Your are confusing descriptive statistics, which describe populations, with the need to focus on a single case - you own. From the point of view of descriptive statistics, the probability of a single case is zero. That is, you with you singular needs do not even exist as far as descriptive statistics are concerned.sp

Actually, statistics CAN describe a single case. I'd like to compare the statistics which describe a single case (me) with statistics that describe a population to which I belong. This is a standard method of medical and psychological diagnosis which can help inform treatment decisions.

Some of us can, and should raise pressure enough to make flow limitations disappear, other's cannot and should not.

I suspected this might be the case, but I did not know. When I don't know stuff, I like to proceed cautiously.

The "others" are a minority, but the only way of learning where you sit in the distribution is by trial and error, on your single case.

I am well versed in the scientific principles of experimentation to test hypotheses.

So am I.

In order to attribute an observed change to your hypothesized cause, other potential explanations need to be ruled out via experimental design (e.g., random assignment to an experimental or control groups in which confounding variables are equalized) or in this case, a quasi-experimental design in which a baseline level of therapy efficacy is measured while keeping all relevant variables constant before changing the one variable (e.g.,[/ Max air pressure) that you hypothesize will cause improvement. It is very common for people to mistakenly attribute observed changes to their suspected cause while failing to consider alternative explanations.
Currently, I am in the process of adjusting to new face masks, new CPAP machine, new air hose temperature, new humidity settings, new ramp settings, new EPR settings, new pressure settings, etc. Therefore, this is not a good time for me to attempt to draw conclusions based on trial and error. At such times, it can be helpful to utilize generalized knowledge and statistical comparisons to relevant populations to inform treatment decisions.

It is quite possible that you and others have generalized knowledge about this field that I lack, and if I knew what you all knew then I would not hesitate to follow your advice to jack up my Min air pressure or Max air pressure or both. However, I've become very wary of "common knowledge" in the medical field which is often be based more on profit incentives or traditional beliefs or trendy narratives than on science. Therefore, I often will explore the reasoning and evidence behind a recommendation rather than just blindly following it.

You clearly have no need of advice from me. I'm sure you can use Goole, and Google Scholar to find any generalized knowledge and do your own statistical comparisons to relevant populations to inform your treatment decisions.

Wishing you much success.

[MJS_]

I just loaded the data from the nap that I took a little while ago (I slept about 45 minutes) to check out my new face mask. I also did increase my pressure settings after reading robysue's post, though not yet by as much as she(?) said may be required. The summary stats show no OA's or H's, and the Flow limitation statistics were: Med 0.00, 95% 0.14, and 99.5% 0.24 which are less than yesterday's Med 0.03, 95% 0.21, and 99.5% 0.31 Are today's Flow Limit. numbers still well above average and a cause for concern? What would be considered acceptable numbers in the absence of OA's or H's occurring?

I like my new ResMed F20 mask, which is much quieter than the Philips Respironics Dreamware mask when they are not leaking (due to air not flowing next to my ears). I also suspect the F20 would be more comfortable and less leak prone if I had gotten the Medium size mask instead of the large. [The sleep tech who measured my face commented that I was between a medium and a large size for the F20. Since I clearly needed the large size in the Dreamware mask, he recommended the large size F20.] The top of the large mask presses against my forehead between my eyebrows and it tended to leak air from area of the cheeks. I'm hoping a slightly shorter and narrower mask will do the trick.

[robysue1]

Thanks again! I suppose it makes sense that I'm having "flow limitations" since my (perhaps ill-advised) goal has been to approach the minimum air pressure needed to prevent OAs. If Hs and OAs are not occurring, then is it common or widely accepted knowledge (among apnea experts) that the air pressure should be increased to eliminate flow limitations? How harmful are air flow limitations in the absence of Hs and OAs?

As palerider has pointed out, flow limitations can be thought of as "hypopnea wannabes" in the sense that it is difficult to get enough air through a partially compromised airway. What I mean by this is that flow limitations can indicate the airway is as a real risk of collapsing. And in that case, more pressure helps smooth out the flow limitation by doing a better job of preemptively preventing the airway from collapsing enough for an H or an OA to be scored.

Having said that, I also want to add that for some people flow limitations get scored because of other reasons. Some people find that severe congestion (which is NOT part of sleep disordered breathing) can cause the machine to score a lot of flow limitations. Some people with deviated septums find that their machines seem to score lots of flow limitations regardless of how high they set the pressure; so the assumption is that the deviated septum may be distorting the shapes of the inhalations in the flow rate curve, and all the pressure in the world isn't going to fix a deviated septum. For a small number of PAPers, restless SWJ breathing can get unstable enough to cause some flow limitations to be scored; for some of these folks, more pressure can lead to more flow limitations, even though that's counterintuitive.

So around here the general consensus seems to be: If you have a lot of flow limitations and you want to experiment, try more pressure to see if the flow limitations start to smooth out. If they get better with more pressure, then that's a good bet that the flow limitations scored by the machine are, in fact, examples where the breathing is becoming unstable specifically because the airway is starting to collapse. If there's no improvement in the flow limitations AND if you're feeling good when you wake up AND your AHI is nice and low, then that can be evidence that your flow limitations might not be tied to an airway that is threatening to collapse, and if you want to cap the max pressure to limit the machine's ability to increase pressure up and up and up in response to the flow limitations, that probably won't compromise the efficacy of your therapy.

Also around here, the general consensus seems to be: If (you are NOT yet feeling good when you wake up OR if you are still dealing with excess daytime sleepiness) AND your AHI is well under 5 AND there's a lot of activity in the Flow Limitation graph, then there's a pretty good chance that your flow limitations are real---i.e. they probably are being scored when your airway is still threatening to collapse and that compromised airway may be disrupting your sleep even though the disruptions are not rising to full-fledged RERAs, Hs, and OAs. And since you're not feeling good on waking or you're still dealing with a lot of daytime sleepiness, it's well worth experimenting with allowing the machine to go where it wants to go in terms of increasing the pressure---as long as you're not dealing with aerophagia.

In my case, I don't typically have a whole lot of flow limitations and I do have a high risk of aerophagia. So I do cap my max IPAP at 9cm to prevent the aerophagia. In the past I have experimented (on a PR machine, not a Resmed) with increasing the max IPAP to as high as 12 or 13cm. And every time, the machine would find at least one point during the night where there were just enough flow limitations being scored to make the pressure go up to the max. But the overall number of flow limitations never went down, the aerophagia raised its ugly head, and I felt worse in the morning. So in my case, I've concluded that one of two things is going on: Either the flow limitations are not caused by an unstable airway OR the flow limitations are real, but I have to make a working compromise between being able to get a good night's sleep (with no aerophagia) and the pressure needed to "fix" the last remaining flow limitations.

What is the normal range for the Flow Limitation summary statistics (median, 95%, 99.5%)?

Nobody knows. I'm serious about that: Nobody knows whether the summary statistics have any real meaning in terms of clinical significance. And nobody knows what a "normal" range for those summary statistics would be.

While Oscar reports the Flow Limitation data numerically, the versions of ResScan that I'm familiar with (from many years ago) had a vertical axis with no numbers on it. Instead, the vertical scale on the Flow Limitation graph consisted of three images: One was a stylized shape of an inhalation with a fully open airway---a nice round hump. At the other end was a stylized shape of a very badly flow limited breath---it looked like a table-top with legs. In the middle was a stylized shape of a possibly flow limited breath that was more angular than the "fully open airway" icon and less like a table-top than the one used to indicate a severely flow limited breath. We do know enough about the flow limitation graphs to know that when the Flow Limitation graph is at 0.0 in Oscar, the Flow Limitation graph in ResScan was at the icon for the stylized shape of an inhalation with a fully open airway. Likewise, when the Flow Limitation graph is near 1.0 in Oscar, it was near the icon for the stylized shape of a very badly flow limited breath.

Since ResScan didn't report numbers on those old Flow Limitation graphs, ResScan never reported summary statistics on for the flow limitation graph. And hence I doubt that even Resmed's engineers have any ideas of what a typical PAPer's median, 95%, 99.5% flow limitation statistics would look like.

Wild ass-guessing would say that if the 95% flow limitation number is 0, you had very few or no breaths with any flow limitation that could be detected by the Resmed software. Wild-ass guessing would also say that if your median flow limitation is above 0.25 (first WAG) or 0.5 (second WAG), then you've probably got some problems with residual flow limitations. And you might just feel better if you increased the pressure enough to smooth those flow limitations out---particularly if you are NOT feeling well when you get up in the morning OR if you are still dealing with an unacceptable level of sleepiness in the daytime or early evening.

Complicating the interpretation of Resmed's flow limitation data even further is this: PR machines score flow limitations in an entirely different fashion: They are scored more like OAs and Hs---i.e. there are "tick marks" with a time duration; so they are scored for specific short stretches of breathing, but PR does not attempt to quantify the "severity" of the flow limitation by assigning it a number between 0 and 1. On a PR machine, OSCAR can display a Flow Limitation Index = (# of FL)/(Run Time), which is gives the average number of flow limitation ticks for each hour the machine is run. How high is an acceptable FLI on a PR machine? Nobody knows. Should the FLI be added to the RDI? Nobody knows.

[robysue1]

I just loaded the data from the nap that I took a little while ago (I slept about 45 minutes) to check out my new face mask. I also did increase my pressure settings after reading robysue's post, though not yet by as much as she(?) said may be required. The summary stats show no OA's or H's, and the Flow limitation statistics were: Med 0.00, 95% 0.14, and 99.5% 0.24 which are less than yesterday's Med 0.03, 95% 0.21, and 99.5% 0.31 Are today's Flow Limit. numbers still well above average and a cause for concern? What would be considered acceptable numbers in the absence of OA's or H's occurring?

I'd have to see the actual data, not the statistics. And for figuring out whether the pressure increase is doing some good or not, I'd like to see at least a couple of nights of data. And know the all-important subjective data of how you felt on waking and whether you were happy enough with your energy level during the day.

(And yes, I'm a she: Robysue is affectionate for Robin Sue. It's a family nickname.)

[robysue1]

Useful analogy! I'd still like to learn how far (or how many SD's for those who are math professors ) my Flow Limitation statistics are from the average, but I suppose I'll start inching my Min/Max air pressures up now.

As I said in an earlier post:

Nobody knows anything about the average, mean, mode, 95% values for what is reported in the Oscar Flow Limitation graph for Resmed machines.

And because the average, mean, and mode are not known, there's no way to compute a SD for this data.

And Resmed's own software package (ResScan) doesn't even slap numbers on its Flow Limitation graph. So it's not clear the numbers in Oscar have any clinical significance other than demonstrating where to look in the flow rate graph for the most distorted looking inhalations.

[Miss Emerita]

I’d describe your flow limitation graph as very busy. One change in settings that may help is to set your EPR to 3. You might want to raise your minimum a little to compensate.

[robysue1]

Alternatively, you just increase your min pressure until your pressure chart is relatively smooth and breathing issues aren't waking you up at night.

Statistics have nothing to do with that.

That would be good advice if...

1) breathing issues were waking me up at night. To the best of my knowledge, they have not. Even when my apnea was more severe and untreated, I would rarely wake up after fully falling asleep except to urinate due to BPH [I'd also feel okay in the morning, but then become overwhelmingly sleepy 8 or 10 or 12 hours later.]

2) My flow limitations with CPAP are caused by my MIN pressure setting being too low, not my MAX pressure setting.

3) My degree of flow limitations pose a significant risk to my health. [I do not know whether they do.]

4) There is little to no chance that raising my pressure until the flow limitations disappear cause side effects that outweigh the benefit. [I do not know whether this is true.]

Here's my two cents about each of the issues you bring up:

Issue #1: Are you still becoming overwhelmingly sleepy 8 or 10 or 12 hours after you wake up? If so, then chances are the flow limitations are still causing your sleep to be less than fully refreshing and your sleep quality could be improved with a judicious increase in pressure to smooth out the flow limitations. And you won't know until you try using a bit more pressure.

Issue #2: Yes, your flow limitations are caused by your MIN pressure being too low. But your MAX pressure is also set so low that the machine cannot increase the pressure up to where the machine thinks the pressure level needs to go. In other words, your pressure graph is hugging the MAX pressure while significant numbers of flow limitations are still occurring. That means the machine's hands have been tied: It would increase the pressure further if it could. But since MAX pressure has already been reached, it just has to sit there and not do anything to try to get rid of the flow limitations. If you are interested in smoothing out the flow rate and eliminating the flow limitations, you will need to increase the min pressure up to 78-8cm and you will need to increase the max pressure as well. How much? Palerider and others would say just set MAX pressure = 20 and MIN pressure = 7.6 and see where the machine wants to go. A more cautious approach (from a stomach that has dealt with aerophagia) would be to increase MIN pressure to 7.6cm and increase MAX pressure to 10cm and see if you're still hitting the max pressure all night long.

Issue #3: Flow limitations are the mildest end of sleep disordered breathing. You are still not breathing completely normally at night even though you are using your CPAP. You might wake up feeling more refreshed and more rested and have enough energy to more easily get through your whole day if there were fewer flow limitations. And the better your body feels on wake and the more energy you have during the whole day, the better the quality of the sleep. And the better the quality of the sleep, the more restorative it is and the better it is for your long term health.

Issue #4: Your AirSense is just blowing air at your upper airway. The most likely adverse side affect of "too much pressure" is a bad case of aerophagia. As someone who has suffered from pretty severe aerophagia, I don't poo-poo that at all. But the thing about aerophagia is that IF you increase the pressure and it triggers a bad case of aerophagia, it's easy enough to lower the pressure back down to a level where you didn't get aerophagia and then increase the pressure much more slowly. Resmed machines allow you to increase pressure in 0.2cm increments. Significant sudden pressure increases can also wake people up. So if you chose to run with a pressure range of 7.6-20 and you suddenly found yourself waking up a lot with the pressure at levels of above 13cm, then it's possible you're one of those people who are sensitive to sudden significant pressure increases. In that case, you can start tightening the range with both a higher min pressure and higher max pressure than you are currently using to see if those flow limitations start to smooth out. The most serious potential side affect of "too much pressure" would be machine-induced central apneas. This is typically only a risk if the pressure stays above 10cm for long periods of time and it typically is a problem for less than 10% of PAPers. And of the 10% if PAPers who are unlucky enough to develop problems with machine-induce central apneas, most of them find the centrals disappear all by themselves after a few weeks of therapy at the appropriate pressure setting. Because you have the data and you know how to look at it in Oscar, it's easy to keep an eye on the centrals. And if they start to increase, you can again lower the pressure back down to the point where they were only occurring very randomly. The upshot of this is that you won't know whether the trade off between (more pressure + less flow limitations) is better, worse, or about the same as (less pressure + more flow limitations) until you experiment with increasing the min and max pressures enough to see if your flow limitations respond to an increase in pressure.

[TheBigTenor]

Palerider,

Quick question. It's been a good year since I've interacted, but I've always wondered about using Oscar software, this question. I know you folks who ask for certain categories in a particular sequence and then zoom in or screenshot this or that, in order to help read our Oscar reports.

Is there anyone in this forum that we can simply send our raw data to that is a sleep analysis that can interpret our readings without us having to manipulate our"overview" or "daily view" in Oscar?

I'd be willing to pay someone to read my Oscar reports to help me figure out WTH is going on to help adjust my settings if I could simply send them my report without having to "tweak, adjust and manipulate" a screenshot to upload here in the forum.

Sorry, to hijack this post, but I'm coming back on board due to some issues and I am curious if there is a licensed sleep analysis person who performs these duties for a fee? I have no issues paying someone qualified to interpret my reports if I can just send the raw data.

[robysue1]

Is there anyone in this forum that we can simply send our raw data to that is a sleep analysis that can interpret our readings without us having to manipulate our"overview" or "daily view" in Oscar?

There is now a site called SleepHQ (url https://home.sleephq.com/ ) that allows you to upload your data and then link to a specific day's data in a cpaptalk.com post. Anybody who clicks on the link can then zoom in on the data as far as they want, as well as scroll through the data.

SleepHQ has two levels of membership: A free level that restricts how many days data are kept on the site and that allows no real access to the SleepHQ forums and a monthly subscription model that you can try for free for 2 weeks. We typically recommend the free membership rather than the monthly subscription.

I'd be willing to pay someone to read my Oscar reports to help me figure out WTH is going on to help adjust my settings if I could simply send them my report without having to "tweak, adjust and manipulate" a screenshot to upload here in the forum.

I'd strongly suggest that you do the following:

1) Upload your data to SleepHQ

2) Create your own (new) thread over here at cpaptalk.com and link to the SleepHQ data in your post. Be sure to give us the relevant information about what problems you are dealing with are. If you have an old thread that gives useful background information, searching for that thread and linking to it will also be useful.

Sorry, to hijack this post, but I'm coming back on board due to some issues and I am curious if there is a licensed sleep analysis person who performs these duties for a fee? I have no issues paying someone qualified to interpret my reports if I can just send the raw data.

Rubicon helps those that he wants to help and he helps them for free.

Uncle Nicko (at SleepHQ) will take your money and do an analysis---if you subscribe to SleepHQ. But a lot of folks around here, including Rubicon, PaleRider, and myself disagree with a lot of what Uncle Nicko says.