Newbie-almost 2 months along, managing ok, (sorta), but CA questions.

Hello, I'm a "veteran" of a whole 2 months of CPAP use; started off looking at lots of YouTube videos, also ended up at the SleepHQ site, but didn't care for the 'Paid" model. Even so, after a disastrous first day, (almost threw the machine in the trash!), I got into the "clinical" settings menu and started tweaking things, allowing me (thankfully) to start to live with it.

I look at the Resmed "My Air" results every morning, it's kinda "basic" but better than nothing, But looking at the OSCAR results is a whole 'nother level! Very confusing (so far), will need to get some "hand-holding" to learn how to read it.

But, what prompted me to join here today and make my first post is something that has me very concerned, specifically regarding CA events.

When I was looking at the comprehensive SleepHQ results during the "trial" period, I first noticed a large number of CA events (very few Apneas, more Hypopneas) and wondered if using a CPAP machine was effective for CA events, considering they're "brain" triggered, not airway obstructions. AND, if I have FEW apneas, then using a CPAP machine might not be the best thing!

My initial AHI result from the "Home" sleep study was 25. Now, using the machine, I've had a few sub 5 event nights, but they've sorta been all over the place between 5 and 10, with a couple spiking up to 13 events.

But here's the strange one (to me, anyway):

Last night, I was awakened at 3 a.m. (wife had set an alarm wrong), she went right back to sleep, but I spent the next half hour unable to fall back asleep, till I took the mask off and shut the machine off.

When I first awoke, I checked the screen and it said 5 "events" for the previous 3 hours - That's an hourly "average", correct? . But then, after not falling asleep at all for the next half hour, I looked at the screen and it said 9 events!

How did I accumulate 4 more "events" if I wasn't even asleep??? And looking later at the OSCAR data, it said that during that same half hour period, there were 17 CA events! (Again, not even asleep during that time)

I've been under the impression that the machine only senses (and reports) Apneas/events during SLEEP, so I'm a bit confused.

If anyone has any thoughts on this, I'd appreciate hearing them.

Lastly, if anyone is able to help me decipher all the OSCAR data so far, I'd appreciate that as well. I just need to be pointed to a help page to explain how to upload and post the results.

Regards, Larry

LBGEE wrote: ↑

Mon Jul 14, 2025 2:49 pm

I've been under the impression that the machine only senses (and reports) Apneas/events during SLEEP, so I'm a bit confused.

These machines can NOT even tell if you are asleep or awake. They have zero way to know if anything it flags is awake/arousal related or sleep related. Where did you get the idea the machine could tell if you were asleep or not?

See this thread.

viewtopic.php?f=1&t=187767&p=1451526#p1451526

LBGEE wrote: ↑

Mon Jul 14, 2025 2:49 pm

When I first awoke, I checked the screen and it said 5 "events" for the previous 3 hours - That's an hourly "average", correct? . But then, after not falling asleep at all for the next half hour, I looked at the screen and it said 9 events!

How did I accumulate 4 more "events" if I wasn't even asleep???

The machine can only measure air flow (your breathing) and the normal irregular breathing can and will confuse the machine into issuing a flag on some irregular breathing. The machine is easily fooled....I do it fairly regularly when I am bored.

See all these CAs/centrals??? I was playing around holding my breath just to see what happened. I NEVER went to sleep until after that second and larger cluster of centrals you see. I had a visit from the insomnia monster that night. None of them were real and they don't matter at all except that I had some trouble falling asleep.

Hello, and thank you for your reply, I appreciate your comments.

To answer your question:

Where did you get the idea the machine could tell if you were asleep or not?

I got that "idea" from Resmed, where it shows information regarding the machine I'm using (Airset 10 Autoset), as copied below:

Key features
Detects sleep onset. AutoRamp™ with sleep onset detection starts by delivering low pressure for greater comfort. Then, after detecting that you’ve fallen asleep, it gradually increases the pressure to the prescribed level.

https://shop.resmed.com.au/products/air ... 8549450050

LBGEE wrote: ↑

Tue Jul 15, 2025 11:30 am

I got that "idea" from Resmed, where it shows information regarding the machine I'm using (Airset 10 Autoset), as copied below:

Key features
Detects sleep onset. AutoRamp™ with sleep onset detection starts by delivering low pressure for greater comfort. Then, after detecting that you’ve fallen asleep, it gradually increases the pressure to the prescribed level.

https://shop.resmed.com.au/products/air ... 8549450050

Ahh...I was wondering if you had stumbled across autoramp promises.

Find me where ResMed says that if it flags a central apnea then you MUST be asleep and never makes mistakes.

Once autoramp is out of the picture (either after the 30 minutes or the machine thinks you are asleep" then we have to rely on the regular auto adjusting and flagging algorithms.

Ok, Thank you.

Here is the OSCAR report for the night I had what seemed like a lot of CA events when I was awake, from approx. 3 to 3 a.m. at which point I took off the mask.
And below it is the following night, where I had an unusually long usage of the CPAP, due to only getting about 4 hours sleep the night before. It seems like they show that I have very few OA events as well.

Any comments on the data would be appreciated. Thank you.

I'll second the point that the machine has no idea whether you're awake or asleep: it's a CPAP, not an EEG. All it can do is guess, based on your breathing. Mine is a cheaper one, that doesn't even try.

But I'm clueless about CA-flagged events. I can generate an "apnea" with every breath for as long as I feel like, but I've never seen a single "clear airway" event. I can stop breathing for the ten-seconds-plus that it takes to count as an "apnea", keeping my mouth open the whole time (or anything else I feel like trying), and it never says "clear airway".

Three things.
1, Having CA's show up right after starting pap therapy is quite common. The cause? You are now having air shoved into your lungs. Your lungs collect O2 and blow off Co2. So with all that air, You are lowering your Co2 levels much more than prior to pap therapy.

2, When asleep your brain only uses a chemical sensor to measure the Co2 level in your blood. If the Co2 level is below a certain range. The brain sees this and says to the lungs, take a break guys until the Co2 returns to the normal range. Bam! you just had a low Co2 Clear Airway event and is not dangerous. And yes, Our brain uses the Co2 level to trigger breathing, not the oxygen level.

3, Those areas of high CA's right after you hit the pillow or are waking up are called SWJ (Sleep Wake Junk) our brain has two levels when it comes to breathing. During our waking hours. Our breathing is both automatic (subconscious brain) and manual control, like when we hold our breathing in swimming. Sleep breathing is 100% subconscious brain controlled. SWJ is quite simply a very sloppy handing off between the two.

Hello Super7Pilot,
Thank you for the information regarding CA events.

So I guess you're saying I shouldn't be concerned about them right now? What about the seeming lack of OA events? I don't show very many.

My initial home sleep study showed an AHI index of 25, so I guess I'm on the right track reducing my events closer to the "under 5" target, which I've only hit 3 or 4 times over 60 days. Most of the time I'm in the 6 to 9 range.

Not sure why the variation, but perhaps it's because I use a Nasal cushion type mask and I always have some degree of nasal congestion. Some nights are worse than others. Perhaps there's a "cause and effect".

Thank you.

LBGEE, we should always strive to get rid of all apnea’s. But CA’s occupy an area of therapy that is the polar opposite in treatment. The higher pressure sometimes needed to treat OA’s, H’s along with using higher EPR to tamp down flow limitations. Will set up the conditions for bringing CA’s front and center.

One thing we can do is to close the gap between the ‘set’ minimum pressure and the actual pressure needed for apnea control. A sharp increase in pressure can cause your brain to wake up and go into the SWJ zone. Which can bring on CA’s.

I would suggest you set your minimum pressure to your median pressure. If we can limit the big pressure increase from too low a pressure. It will help to prevent awakenings from big pressure increases and hopefully avoid SWJ.