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OA or CA from graph without flags
#1
Without the flags in Sleepyhead, is there any to differentiate between an OA and a CA based on the graphs?I thought that I had it doped out but my theory does not seem to hold. I thought that the mask pressure squiggles from the FOT might be sharper for OA and less distinct for CA. Does not seem like that holds up.

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PaytonA

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#2
(11-13-2014, 10:21 PM)PaytonA Wrote: Without the flags in Sleepyhead, is there any to differentiate between an OA and a CA based on the graphs?I thought that I had it doped out but my theory does not seem to hold. I thought that the mask pressure squiggles from the FOT might be sharper for OA and less distinct for CA. Does not seem like that holds up.

Hi PaytoA,

Zooming in on the Flow (not the High Rate Pressure), I would expect the FOT to cause less Flow during obstructive apnea events than during CA events. Temporarily changing the vertical scale on the Flow to -20 to +20 Liter/minute may be helpful to see this.

I don't know what other indication there would be to differentiate CA from OA.

However, if there is rapidly-varying Leak, this can cause false CA flags. If the machine does not sense the end of inhalation or exhalation within 10 seconds, it would score an apnea, and, occasionally, constantly increasing or decreasing Leak will make the Flow look always positive or always negative for over 10 seconds, resulting in a CA or in an Unknown type apnea being scored.



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#3
Normally, I can see flow limitation before an OA scored but not always, some OA can just occur without any warning

CA not associated with flow limitation or pressure increase
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