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Did Dreamstation or OSCAR fail to flag or misclassify abnormal breathing events
#11
RE: Did Dreamstation or OSCAR fail to flag or misclassify abnormal breathing events
Because that example is NOT flat.  
There have not been any medical studies that I have seen talking about consecutive almost events and the effect of those, ( I feel that they are obvious ).  There is also no study talking about the effect of 9-second apnea events, just as an event that lasts 45 seconds counts the same as a 10-second event.  Especially when your event count is down and you are still having issues YOU need to look at the detailed zoomed view because I'll guaranty you that your doctor will not.

Thank you and good luck,  I'm out  of here.
Fred Bonjour - Project Manager and Lead Tester for OSCAR - Open Source CPAP Analysis Reporter

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#12
RE: Did Dreamstation or OSCAR fail to flag or misclassify abnormal breathing events
ChinaMan Wrote:How can you defend not flagging a flat flow rate line for at least like 15s while flagging other isolated flow rate graphs as FL? Come one, it's not rocket science.

We don't defend it. Just for the record I'll state it again Oscar does not interpret the data to flag events. It reports what is told it by the machine. If the machine doesn't flag a 15 second event then Oscar won't report it, simple as that. So your beef isn't with Oscar, it's with Philips.

FYI all the manufacturers keep their data formats secret. ResScan at least uses a standard EDF file format but without publishing the "key" to what data is encoded in each file. Philips uses a variety of proprietary formats, where a reading or event on one machine is reported differently from the same event on another machine.  The Oscar developers have done a major re-write of the Philips parsers to improve consistency and accuracy, and this will be included in the next release. However that won't change the fact that Oscar still relies on data provided by the machine.

ChinaMan Wrote:I did call Philips customer service asking for explanation, the Philips technician hinted there was something wrong with OSCAR, that I should use Philips's software to look at the data.

This sounds like a very good idea. You can download the Philips software (Encore) from our private files & links forum http://www.apneaboard.com/forums/Forum-P...-and-Links  If I recall correctly there are two versions of Encore: Pro and Basic. Basic is much easier to use but does not have all the bells & whistles of the Pro version (which apparently is a mongrel to use). Why don't you try your same SD car in Encore and compare the output. I for one would be interested in hearing of any discrepancies.
#13
RE: Did Dreamstation or OSCAR fail to flag or misclassify abnormal breathing events
(10-31-2019, 07:43 PM)DeepBreathing Wrote:
ChinaMan Wrote:How can you defend not flagging a flat flow rate line for at least like 15s while flagging other isolated flow rate graphs as FL? Come one, it's not rocket science.

We don't defend it. Just for the record I'll state it again Oscar does not interpret the data to flag events. It reports what is told it by the machine. If the machine doesn't flag a 15 second event then Oscar won't report it, simple as that. So your beef isn't with Oscar, it's with Philips.

FYI all the manufacturers keep their data formats secret. ResScan at least uses a standard EDF file format but without publishing the "key" to what data is encoded in each file. Philips uses a variety of proprietary formats, where a reading or event on one machine is reported differently from the same event on another machine.  The Oscar developers have done a major re-write of the Philips parsers to improve consistency and accuracy, and this will be included in the next release. However that won't change the fact that Oscar still relies on data provided by the machine.

ChinaMan Wrote:I did call Philips customer service asking for explanation, the Philips technician hinted there was something wrong with OSCAR, that I should use Philips's software to look at the data.

This sounds like a very good idea. You can download the Philips software (Encore) from our private files & links forum http://www.apneaboard.com/forums/Forum-P...-and-Links  If I recall correctly there are two versions of Encore: Pro and Basic. Basic is much easier to use but does not have all the bells & whistles of the Pro version (which apparently is a mongrel to use). Why don't you try your same SD car in Encore and compare the output. I for one would be interested in hearing of any discrepancies.

I was saying that a Flow Rate graph suddenly indicates 0 or near 0 flow rate for like 20s, the the event was not flagged; while another apparently "normal" flow rate graph was flagged as FL, then either Philips or OSCAR has major things to explain, because it might actively mislead patients. And again as I said, I called Philips, was told that it doesn't support OSCAR, so it can't tell me why.
#14
RE: Did Dreamstation or OSCAR fail to flag or misclassify abnormal breathing events
It could be that Philips wouldn't like to admit the machine didn't get something right. OSCAR is a Reporting tool as in its name. As was mentioned, you don't have to use OSCAR.
Dave

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INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEBSITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.






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#15
RE: Did Dreamstation or OSCAR fail to flag or misclassify abnormal breathing events
(10-31-2019, 09:07 PM)SarcasticDave94 Wrote: It could be that Philips wouldn't like to admit the machine didn't get something right. OSCAR is a Reporting tool as in its name. As was mentioned, you don't have to use OSCAR.

Philips simply said it didn't know OSCAR, so it can't tell whether I was getting accurate results.

Look at this graph, the flow rate was at or near 0 for like 20s, but was not even flagged as Flow Limitation: http://www.apneaboard.com/forums/attachm...?aid=16657
#16
RE: Did Dreamstation or OSCAR fail to flag or misclassify abnormal breathing events
OSCAR reports flags from your machine data. You can try Encore as was suggested. Compare results between the 2 reporting tools as suggested. Decide which you want to put your trust in after that.
Dave

OSCAR
Standard OSCAR Chart Order
Mask Primer
Dealing With A DME
Soft Cervical Collar Wiki
INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEBSITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
#17
RE: Did Dreamstation or OSCAR fail to flag or misclassify abnormal breathing events
I find that IMHO that PR does a very poor job of flagging flow limitations. If ANY FL events are flagged a detailed examination should be considered. In THIS example NOTHING meets the 10 second requirement.
Fred Bonjour - Project Manager and Lead Tester for OSCAR - Open Source CPAP Analysis Reporter

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#18
RE: Did Dreamstation or OSCAR fail to flag or misclassify abnormal breathing events
(10-31-2019, 09:31 PM)bonjour Wrote: I find that IMHO that PR does a very poor job of flagging flow limitations.  If ANY FL events are flagged a detailed examination should be considered.  In THIS example  NOTHING meets the 10 second requirement.

If that's the fault of PR, then it also does extremely poor job in classifying everything in terms of lengths or characteristics of abnormal breathing events.

E.g., it says the CA ended right there, but the flow rate was still near or at zero for at least another 12s after the alleged CA end: http://www.apneaboard.com/forums/attachm...?aid=16653 ;

      And after the H ends, there was at least a flat flow rate graph for another 16s: http://www.apneaboard.com/forums/attachm...?aid=16655;

     Also, after the FL end, there was at least 11s of flow rate near or at 0: http://www.apneaboard.com/forums/attachm...?aid=16654


If it's indeed PR's fault, then it seriously underestimates the AHI; the true AHI might be much higher.
#19
RE: Did Dreamstation or OSCAR fail to flag or misclassify abnormal breathing events
Despite the fact that that is a bad segment of abnormal breathing, what is it that you are not understanding about the fact the NOTHING in that example meets a 10 second requirement to be officially called an event?  THERE IS NO RULE THAT STATES THAT MULTIPLE EVENTS LASTING LESS THAN 10 SECONDS BUT TOTALING MORE 10 SECONDS IS AN EVENT!!!

Should there be?  That is an entirely different discussion.  Get a study group to document and prove that and get the AASM to state that.  and yes, it does seem that it should be common sense.
Fred Bonjour - Project Manager and Lead Tester for OSCAR - Open Source CPAP Analysis Reporter

Download OSCAR
New to Apnea? Helpful tips to ensure success
Soft Cervical Collar
Mask Primer
Dealing with a DME
Organize Charts
Optimizing Therapy
#20
RE: Did Dreamstation or OSCAR fail to flag or misclassify abnormal breathing events
(10-31-2019, 10:26 PM)bonjour Wrote: Despite the fact that that is a bad segment of abnormal breathing, what is it that you are not understanding about the fact the NOTHING in that example meets a 10 second requirement to be officially called an event?  THERE IS NO RULE THAT STATES THAT MULTIPLE EVENTS LASTING LESS THAN 10 SECONDS BUT TOTALING MORE 10 SECONDS IS AN EVENT!!!

Should there be?  That is an entirely different discussion.  Get a study group to document and prove that and get the AASM to state that.  and yes, it does seem that it should be common sense.

Then why numerous events were flagged despite the graphs say they last less than 10s? 

E.g., the attached first graph shows a FL lasting 6s; the second attached graph shows a OA lasting 8s(although I think it lasted more than 8s).






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