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Did Dreamstation or OSCAR fail to flag or misclassify abnormal breathing events
#1
Did Dreamstation or OSCAR fail to flag or misclassify abnormal breathing events
Last night, there were many abnormal Flow rate graphs, but either the Dreamstation or OSCAR failed to flag or misclassified the events.

E.g., in the first attached graph, the flow rate was near or at 0 even for at least another 13s after the 26s CA event flagged by the machine, but the graph indicates the CA event was over; in the second graph, the flow rate was near or at 0 for at least for another 26s, but the event was flagged as a single 14s FL event; in the third graph, there was at least another 9s 0 flow rate after the 16s H event.

And there were many patently abnormal flow rate graphs, but they were not flagged as any events.

How can I trust either AHI OR RDI of the Dream Station or OSCAR?


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#2
RE: Did Dreamstation or OSCAR fail to flag or misclassify abnormal breathing events
(10-31-2019, 03:25 PM)ChinaMan Wrote: Last night, there were many abnormal Flow rate graphs, but either the Dreamstation or OSCAR failed to flag or misclassified the events.

E.g., in the first attached graph, the flow rate was near or at 0 even for at least another 13s after the 26s CA event flagged by the machine, but the graph indicates the CA event was over; in the second graph, the flow rate was near or at 0 for at least for another 26s, but the event was flagged as a single 14s FL event; in the third graph, there was at least another 9s 0 flow rate after the 16s H event.

And there were many patently abnormal flow rate graphs, but they were not flagged as any events.

How can I trust either AHI OR RDI of the Dream Station or OSCAR?

I just called Respironics customer service asking for explanation, was told that Philips doesn't support OSCAR so she didn't know what I was talking about.

Does OSCAR have serious problem or Dreamstation have problem?
#3
RE: Did Dreamstation or OSCAR fail to flag or misclassify abnormal breathing events
And look at this attached flow rate graph, the flow rate dropped to near ZERO for at least 22s, but OSCAR didn't even flag the event as flow limitation.


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#4
RE: Did Dreamstation or OSCAR fail to flag or misclassify abnormal breathing events
you might get a quicker response from the oscar folks by posting in the software forum. from what I read, displaying data from some machines is a work in progress in oscar.



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#5
RE: Did Dreamstation or OSCAR fail to flag or misclassify abnormal breathing events
ChinaMan, OSCAR doesn't flag events, it is your CPAP that does.  Based on the graph you posted, it appears that your lack of flow lasted for about 5 seconds before some activity was detected.   Of course I've been known to be wrong before, just ask my wife.
Crimson Nape
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#6
RE: Did Dreamstation or OSCAR fail to flag or misclassify abnormal breathing events
Hi Chinaman, 

1)  Often events you see in the waveform have just not gone on long enough to get scored as an Official Flagged Event.

2) Generally OSCAR does a pretty good job of displaying whatever data is sent by the XPAP machine so could just as the vendor how they score or do not score their events and never need to mention OSCAR. 

3) The two links below include an intro into how OSCAR scores and / or presents data from the machines.  

4) The short of it for me..  In part because of cases like you posted above I learned what most of the rest of the charts in OSCAR work and look across the Pressure, Resp Rate Minute Vent, Leak Rate, and Flow Limit charts to tell me what is really happening when you see that waveform.  



WillSleep


http://www.apneaboard.com/wiki/index.php...OSCAR_Help


http://www.apneaboard.com/wiki/index.php...rpretation

INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
#7
RE: Did Dreamstation or OSCAR fail to flag or misclassify abnormal breathing events
I will add that the series of events that you posted the graph of IS significant if there are enough of them. (one 'event' is rarely significant by itself)
Fred Bonjour - Project Manager and Lead Tester for OSCAR - Open Source CPAP Analysis Reporter 
OSCAR

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#8
RE: Did Dreamstation or OSCAR fail to flag or misclassify abnormal breathing events
(10-31-2019, 04:53 PM)bonjour Wrote: I will add that the series of events that you posted the graph of IS significant if there are enough of them.  (one 'event' is rarely significant by itself)

The machine did flag isolated events. And the failures to flag and misclassifications were patently false and inexcusable. Let's admit they are serious bugs, which may explain when AHIs are low why some people still don't feel good––Because many abnormal breathing events were not flagged or misflagged.
#9
RE: Did Dreamstation or OSCAR fail to flag or misclassify abnormal breathing events
Contact the medical community and lobby for a change to the algorithms used to detect events. OSCAR reports what the machine detects, and that follows the current medical standard.

You can do some of that yourself. In Preferences/CPAP there is a section for Custom CPAP User Event Flagging. As stated "Custom flagging is an experimental method of selecting events missed by the machine" You can define the flow restriction and the event duration.
Fred Bonjour - Project Manager and Lead Tester for OSCAR - Open Source CPAP Analysis Reporter 
OSCAR

Download OSCAR
New to Apnea? Helpful tips to ensure success
Soft Cervical Collar
Mask Primer
Dealing with a DME
Organize Charts
Attaching Charts

INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
#10
RE: Did Dreamstation or OSCAR fail to flag or misclassify abnormal breathing events
(10-31-2019, 06:58 PM)bonjour Wrote: Contact the medical community and lobby for a change to the algorithms used to detect events.  OSCAR reports what the machine detects, and that follows the current medical standard.

You can do some of that yourself.  In Preferences/CPAP there is a section for Custom CPAP User Event Flagging.  As stated "Custom flagging is an experimental method of selecting events missed by the machine"  You can define the flow restriction and the event duration.

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.

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.



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