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OSCAR - Flow Limitations
#1
OSCAR - Flow Limitations
       




I've noticed lately that the flow limitations chart and the left hand column don't match up. For example, the chart has a max FL of .66 but when you look at the left hand column and the overview tab is says max FL is .20. Is that a bug or am I missing something?
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#2
RE: OSCAR - Flow Limitations
The numbers at the top left of each chart are based on the time period of the chart. The tool-tip data is for the single day, and it agrees with the Daily data. There are several days earlier in the chart which had a higher flow limitation max, so if you mouse over the tall ones, I'm sure you will find the max value in the top left.
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#3
RE: OSCAR - Flow Limitations
The left hand value in oscar is a 95% value and not a maximum value
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#4
RE: OSCAR - Flow Limitations
max in oscar is said to be 99% in daily tab. maybe 100% on statistics page?
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#5
RE: OSCAR - Flow Limitations
I think I didn’t explain it right. My actual max in the daily FL chart is .66. But in the left side column it says under MAX it says .20. And in the overview charts when I mouse over it it says PEAK, which I’m assuming is another way of saying MAX of .20. The left side column and overview is less than a third of my actual max. I realized it cause I was going over my charts looking at how I’ve progressed and the left side column and overview does not coincide. At far as flow limitations are concerned. I haven’t noticed any others. My focus was FL. 

Bonjour what’s your take on this? Am I right and this is a bug or am I not understanding how to interpret OSCAR?
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#6
RE: OSCAR - Flow Limitations
(12-02-2019, 12:02 PM)Osiris357 Wrote: I think I didn’t explain it right. My actual max in the daily FL chart is .66. But in the left side column it says under MAX it says .20. And in the overview charts when I mouse over it it says PEAK, which I’m assuming is another way of saying MAX of .20. The left side column and overview is less than a third of my actual max. I realized it cause I was going over my charts looking at how I’ve progressed and the left side column and overview does not coincide. At far as flow limitations are concerned. I haven’t noticed any others. My focus was FL. 

Bonjour what’s your take on this? Am I right and this is a bug or am I not understanding how to interpret OSCAR?

What version are you actually using?
SH had in many places not used actual Maxes, typically 95%.  At OSCAR we feel that this kind of interpretation is incorrect.  We are performing a deep dive into displayed statistics for that reason.  
The OSCAR team will correct any and all incorrect calculations that we find.

We know that this was done because frequently the max was a single datapoint, frequently at startup, a spike which has no practical meaning. A 95% value removes these but they MUST be called what they are. I do know that many have been corrected though not in the released version, (our latest internal testing version is testing-4).  We are a few weeks from initiating a new release cycle,  That means internal testing for the next release.  No promises on date.
Fred Bonjour - Project Manager and Lead Tester for OSCAR - Open Source CPAP Analysis Reporter 
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#7
RE: OSCAR - Flow Limitations
it is reporting 99% as max, not the actual max. it drops the top 1% of flow limitations (based on time spent in flow limitation or time machine was used?) and uses the remaining "max" as the number displayed.
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#8
RE: OSCAR - Flow Limitations
(12-02-2019, 12:20 PM)bonjour Wrote:
(12-02-2019, 12:02 PM)Osiris357 Wrote: I think I didn’t explain it right. My actual max in the daily FL chart is .66. But in the left side column it says under MAX it says .20. And in the overview charts when I mouse over it it says PEAK, which I’m assuming is another way of saying MAX of .20. The left side column and overview is less than a third of my actual max. I realized it cause I was going over my charts looking at how I’ve progressed and the left side column and overview does not coincide. At far as flow limitations are concerned. I haven’t noticed any others. My focus was FL. 

Bonjour what’s your take on this? Am I right and this is a bug or am I not understanding how to interpret OSCAR?

What version are you actually using?
SH had in many places not used actual Maxes, typically 95%.  At OSCAR we feel that this kind of interpretation is incorrect.  We are performing a deep dive into displayed statistics for that reason.  
The OSCAR team will correct any and all incorrect calculations that we find.

We know that this was done because frequently the max was a single datapoint, frequently at startup, a spike which has no practical meaning. A 95% value removes these but they MUST be called what they are. I do know that many have been corrected though not in the released version, (our latest internal testing version is testing-4).  We are a few weeks from initiating a new release cycle,  That means internal testing for the next release.  No promises on date.

I see and I’m using v1.0.1-r-1....I was just about to ask when the next version is going to be released. Am I using an older version?
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#9
RE: OSCAR - Flow Limitations
(12-02-2019, 12:02 PM)Osiris357 Wrote: I think I didn’t explain it right. My actual max in the daily FL chart is .66. But in the left side column it says under MAX it says .20. And in the overview charts when I mouse over it it says PEAK, which I’m assuming is another way of saying MAX of .20. The left side column and overview is less than a third of my actual max. I realized it cause I was going over my charts looking at how I’ve progressed and the left side column and overview does not coincide. At far as flow limitations are concerned. I haven’t noticed any others. My focus was FL. 

Bonjour what’s your take on this? Am I right and this is a bug or am I not understanding how to interpret OSCAR?

I'm not Bonjour (and I see he's already replied).

I think I understood your explanation, and I could see some of the same in my own charts. I didn't look at the Overview tab though, just the statistics summary in the middle of the left sidebar. On your graph (and on mine) there seem to be points on the Flow Limitation graph that are higher than the Flow Limitation Max in the Statistics sidebar.

I found an easier way to show what I believe to be the same effect is to go to the Flow Limitation graph and ask it to plot a dotted line corresponding to the Peak Flow Limit. When I do this, I find the level of the dotted line matches the Max value in the Statistics sidebar, and that the graph has points above the dotted line. Try it on your graph. 

If I greatly expand the timescale of the Flow Limitation graph, it looks to me rather like the AHI graph, in that it seems to be a plot of a rolling average of values over some time period, an hour for AHI, clearly much less for FL.

While the AHI graph seems to computed within Oscar, based on events provided by ResMed (in our case), the Flow Limitation graph gets its raw data from ResMed via SD Card, and the data seems to be correctly plotted.

I have not yet discovered where in Oscar the statistics calculations are done, so I won't comment on bug possibilities.

I also don't know enough about what ResScan displays, but it does occur to me that if I intended to write what some might describe as a "better, improved ResScan", then I would probably consider if I might ever want to make my efforts be "bug compatible".

The SD Card data shows Flow limitation to be data sampled every 2 seconds, with no units, with values in the range 0 to 100. I guess I need to read up on what these data values actually are, and how they are computed(either by ResMed, or maybe there's a standard).So far I've seen an NIH article that says it's a double derivative of flow rate, but so far I'm only in the introduction.
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#10
RE: OSCAR - Flow Limitations
(12-02-2019, 01:52 PM)mjphyi Wrote:
(12-02-2019, 12:02 PM)Osiris357 Wrote: I think I didn’t explain it right. My actual max in the daily FL chart is .66. But in the left side column it says under MAX it says .20. And in the overview charts when I mouse over it it says PEAK, which I’m assuming is another way of saying MAX of .20. The left side column and overview is less than a third of my actual max. I realized it cause I was going over my charts looking at how I’ve progressed and the left side column and overview does not coincide. At far as flow limitations are concerned. I haven’t noticed any others. My focus was FL. 

Bonjour what’s your take on this? Am I right and this is a bug or am I not understanding how to interpret OSCAR?

I'm not Bonjour (and I see he's already replied).

I think I understood your explanation, and I could see some of the same in my own charts. I didn't look at the Overview tab though, just the statistics summary in the middle of the left sidebar. On your graph (and on mine) there seem to be points on the Flow Limitation graph that are higher than the Flow Limitation Max in the Statistics sidebar.

I found an easier way to show what I believe to be the same effect is to go to the Flow Limitation graph and ask it to plot a dotted line corresponding to the Peak Flow Limit. When I do this, I find the level of the dotted line matches the Max value in the Statistics sidebar, and that the graph has points above the dotted line. Try it on your graph. 

If I greatly expand the timescale of the Flow Limitation graph, it looks to me rather like the AHI graph, in that it seems to be a plot of a rolling average of values over some time period, an hour for AHI, clearly much less for FL.

While the AHI graph seems to computed within Oscar, based on events provided by ResMed (in our case), the Flow Limitation graph gets its raw data from ResMed via SD Card, and the data seems to be correctly plotted.

I have not yet discovered where in Oscar the statistics calculations are done, so I won't comment on bug possibilities.

I also don't know enough about what ResScan displays, but it does occur to me that if I intended to write what some might describe as a "better, improved ResScan", then I would probably consider if I might ever want to make my efforts be "bug compatible".

The SD Card data shows Flow limitation to be data sampled every 2 seconds, with no units, with values in the range 0 to 100. I guess I need to read up on what these data values actually are, and how they are computed(either by ResMed, or maybe there's a standard).So far I've seen an NIH article that says it's a double derivative of flow rate, but so far I'm only in the introduction.
Yes that is exactly what I was trying to say. I used to have that line on FL chart but it didn't look accurate at all so I turned it off
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