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OA or CA from graph without flags
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PaytonA Online
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Machine: ResMed S9 VPAP Auto
Mask Type: Full face mask
Mask Make & Model: Resmed Mirage Quattro
Humidifier: H5i(distilled-top up)
CPAP Pressure: VAuto MinE14.0 MaxI 20.6 PS4.0
CPAP Software: ResScan SleepyHead

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Sex: Male
Location: Orange County,California

Post: #1
OA or CA from graph without flags
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
11-13-2014 10:21 PM
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vsheline Offline

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Machine: S9 VPAP Adapt (USA Model# 36007, not better 36037 or 36067)
Mask Type: Full face mask
Mask Make & Model: F10 or SimPlus w/ 2Liners. MirageQuatro & Gecko gel pad
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Other Comments: Marfan Syndrome, chronic bradycardia, occasional Cheyne-Stokes Respiration

Sex: Male
Location: California, USA

Post: #2
RE: OA or CA from graph without flags
(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.

Membership in the Advisory Member group should not be understood as in any way implying medical expertise or qualification for advising Sleep Apnea patients concerning their treatment. The Advisory Member group provides advice and suggestions to Apnea Board administrators and staff on matters concerning Apnea Board operation and administrative policies - not on matters concerning treatment for Sleep Apnea. I think it is now too late to change the name of the group but I think Voting Member group would perhaps have been a more descriptive name for the group.
(This post was last modified: 11-13-2014 11:05 PM by vsheline.)
11-13-2014 10:49 PM
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zonk Offline

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Post: #3
RE: OA or CA from graph without flags
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
(This post was last modified: 11-13-2014 11:04 PM by zonk.)
11-13-2014 11:01 PM
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