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Flow increase before the event ?
#1
Flow increase before the event ?
Hi,
I'm new to OSCAR and chart reading.

My AHI was diagnosed by my Pneumologist at 11. She said it consists mostly of flow restrictions.

I've been using a ResMed AirSense 11 AutoSet with a Simplus F&P (full face) mask for a week now.
Right now we are trying a low pressure (4 cmH20) because I have aerophagia when using the machine. At 4cm I can tolerate 8 hours of CPAP but not at 9 cm.

According to OSCAR and the ResMed data, last night my AHI was 3.77. 
However when I add in Custom Event Flagging based on Flow Restrictions > 50%, I can see that I have as many UFs as CA. 
Since UFs are not included in the AHI, the AHI only gives a partial view of the situation.
When I zoom in to see what is going on around the CA and UF events, most of the time I find that 20 seconds prior to the start of the Event there was an increase in the Flow Rate, the Tidal Volume and the Minute Vent.
I would have expected the Flow Rate to increase AFTER the event, not BEFORE, but as I said I'm new to this ;-) 
What do you make of this ? 

Thanks...

V.


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#2
RE: Flow increase before the event ?
4 is low for most adults. I’m surprised you can sleep with the pressure so low. You shouldn’t be surprised to have flow limits at 4.

A flow increase before an event can signify an arousal. You wake up, roll around while holding your breath, and then settle back in to sleep. That’s what I see in my data at times. You can also see this during REM transition which is what might be going on in one of your screen captures where pattern is undulating and wavy before the event.
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#3
RE: Flow increase before the event ?
That flow increase is an arousal, likely with you tossing to reposition yourself and holding your breath as you do as indicated by the logged, but likely false, central apnea.
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