Airsense 10 CA vs OA

[DaveD]

Can the Airsense 10 reliably tell the difference between CA and OA events?

I'm a couple weeks into this, and I'm seeing a split between OA and CA events. Last night showed AHI of 21, with CA at 18 and OA at 2. I am running APAP 6/8 at the moment with a Fitlife Total Face XL mask.

The doctor set up the machine for CPAP 10, with very poor results (worst night was 49). I bumped it to 12, got better results, but lots of noisy leaks so very little sleep. Per advice from some members of this board, I have ordered a size L mask. I'm stuck with the Total Face because of previous DCR surgery. I'm running 6/8 at the moment, sort of treading water until the new mask arrives.

It looks like the machine sends out a test signal when an apnea is detected. A series of pressure pulses are generated, and the amplitude of the resultant air flow determines whether the airway is blocked. Makes perfect sense. I'm wondering whether the XL Total Face mask if fooling the machine - when these pulses are being sent, the mask "bounces" quite a bit, which increases the airflow from the test pressure pulses, much like a couple of lungs would. The machine has no setting for a Total Face mask, only full face. I have looked at the Flow Rate graph, and I can't seem much difference in the test signal amplitude preceding the OA vs CA markers.

I have an appointment with my doctor on 2/1, and I will discuss this with him then, since I can't seem to get a call back. While he seems competent, I doubt if he took Fluid Dynamics in med school.

I tried to attach a zip of my SD card, but failed due to size limitations, nor could I post a link. Not sure how to get around this.....

Any thoughts would be greatly appreciated.

[OpalRose]

You can post attachments.
http://www.apneaboard.com/forums/misc.ph...elp&hid=19

Your doctor perscribed 10 CPAP, so your APAP setting should be 2cm below that and 2 above, with a range of 8 to 12.

Post a couple nights, include events graphs, pressure and leak graph, and flow limitation graph.
Also include the detailed information to the left.

[DaveD]

Will do, thanks.

[DaveD]

Your doctor perscribed 10 CPAP, so your APAP setting should be 2cm below that and 2 above, with a range of 8 to 12.

OpalRose - I am running 6/8 at the moment due to mask leaks, seems OK at 8, not so good at 10 - I had to really cinch down the Total Face mask to stop the leaks. I will be getting a new mask in a day or so, and will set to 8/12. Thanks.

[eseedhouse]

Can the Airsense 10 reliably tell the difference between CA and OA events?

Yes, pretty well though of course it's not a lab instrument. When it detects that your breathing has stopped it sends out pulses of air at around 4 Hz (IIRR). If the airway is closed it can detect these waves reflected back. If it is open they are absorbed deeper in your respiratory track so very little is reflected.

[Pete]

Can the Airsense 10 reliably tell the difference between CA and OA events?

Of course the short answer is no. But the long one is maybe. I had a similar situation on a S9 CPAP machine. I had numerous CA events. My sleep specialist said they were not Central Apneas, but about six months and another sleep study later I convinced her they were, in fact Central Apneas.

It took a VPAP ASV machine and a nasal mask to bring them under control. Full face masks triggered many more CA's in my case. Even with the greater leaks and lower pressures with a nasal mask it got my central apneas under control and now I have no OSA events at all...

[eseedhouse]

The machine can only say that you stopped breathing and your airway was open. That doesn't prove that it was a true "central" apnea, which originates in your brain and which the machine knows nothing about. So it's "Clear Airway" that is reported, not "Central Apnea", but it's a pretty good chance that they are actually centrals. You can only prove this unambiguously with EEG leads stuck to your head, and I don't think I'd want a CPAP machine that made me do that every night...

[Dreams of Green]

Can the Airsense 10 reliably tell the difference between CA and OA events? I'm a couple weeks into this, and I'm seeing a split between OA and CA events. Last night showed AHI of 21, with CA at 18 and OA at 2. I am running APAP 6/8 at the moment with a Fitlife Total Face XL mask.

I think the issue is less whether it can tell the difference between them, and more that it's very common for events reported as CA events not to be real CA events, but rather sleep/awake events. It's possible those CA's aren't real and nothing to worry about.

If you can post your graphs they may give some clues.

[PaytonA]

You can get sleep/wake OAs too. Yes, the CPAP can not yet tell if you are asleep or awake. You make a good SWAG at the events that should be ignored.

Best Regards,

PaytonA

[Inspired]

Can the Airsense 10 reliably tell the difference between CA and OA events? I'm a couple weeks into this, and I'm seeing a split between OA and CA events. Last night showed AHI of 21, with CA at 18 and OA at 2. I am running APAP 6/8 at the moment with a Fitlife Total Face XL mask.

I think the issue is less whether it can tell the difference between them, and more that it's very common for events reported as CA events not to be real CA events, but rather sleep/awake events. It's possible those CA's aren't real and nothing to worry about.

If you can post your graphs they may give some clues.

What are some of the "clues" in the graphs, to help distinguish CA vs sleep/awake events?
Thanks for sharing with all the newbies like me.