Question about types of apneas (sleepyhead data)

[Ayleone]

So I have been looking through my past 4 weeks of usage (since I started CPAP in other words) in Sleepyhead, and I noticed something interesting.

I was diagnosed with Obstructive Sleep Apnea, and when looking through my data I see that nearly every night I have more "clear airway" apneas than any other. An average night would be 25% hypopnea, 25% obstructive, and 50% clear airway. Now upon looking online, I found "clear airway" means Central. I also found some forum posts where it was said that Central apneas should have shown up in a sleep study, and also that they can just mean you're awake.

Does anyone have more info? Should I be telling my Dr. these findings?

[Pugsy]

How many Clear Airway events are you seeing over the entire night and how many hours are we talking about?
50% of 10 isn't anything to worry about over 6 hours.
50% of 50 over 4 hours might be worth looking at.

Some central occurrence is normal...as in with sleep onset centrals.
Also the machines often will flag by mistake some awake/semi awake breathing irregularities by mistake and most often they get flagged as centrals. So if people are seeing groupings of centrals close to awake times...maybe they aren't real centrals.

[robysue]

An average night would be 25% hypopnea, 25% obstructive, and 50% clear airway. Now upon looking online, I found "clear airway" means Central.

What is the total AHI? And what is the CAI? If both are less than 5.0, then you really don't need to over react to your machine scoring some "centrals". But if the CAI all by itself is way above 5.0 and the CAs are being scored during times when you are pretty sure you were sound asleep, then there may indeed be something going on that you need to inform the sleep doc about.

I also found some forum posts where it was said that Central apneas should have shown up in a sleep study, and also that they can just mean you're awake.

If you had a serious problem with Central Sleep Apnea as a primary condition, the central apneas would have shown up on your diagnostic sleep study. And you might have been put on a different machine right from the start of your PAP therapy.

If your machine is simply scoring a few run of the mill "sleep transition centrals" each night, then you may have had some on your sleep studies, but they may not have been scored because an occasional sleep transition central is not considered to be part of sleep disturbed breathing because they occur as you are falling asleep and the control of breathing is being handed off from your voluntary nervous system to your autonomous nervous system.

If you are spending long periods of time awake or semi-wake breathing with the mask on, then your machine may be mis-scoring normal wake breathing patterns as CAs: When we're awake our breathing patterns are much less regular than when we are asleep. And we do things like hold our breath for several seconds when concentrating on something without always realizing it---even something as simple as turning over in bed when we have a six foot hose attached to our nose. If similar wake breathing patterns happened during your diagnostic and titration sleep studies, they would not have been scored since the EEG would have indicated you were indeed awake when the "apnea" happened.

But finally: A small minority of new PAPers do develop problems with central apneas after starting PAP therapy. Sometimes this problem emerges immediately on the titration study and the CAs show up on that test's results, but not the diagnostic test's results. Sometimes this problem doesn't emerge until the new PAPer is trying to use the PAP at home each night. This kind of central apnea often occurs only when the pressure reaches a certain threshold (the threshold can vary from person to person), and they are commonly referred to as "pressure induced central apneas." A lot of the time, the problem with pressure induced central apneas will resolve itself over the first few weeks of PAP therapy, and hence many sleep docs will encourage the new PAPer to just keep trying for a few weeks before "doing anything" about the pressure induced centrals. For a very small number of PAPers, the problem with pressure induced centrals does NOT resolve with time, and these folks usually wind up with a diagnosis of Complex Sleep Apnea. If the number of CAs remains clinically significant over a long period of time while on PAP therapy, the doctor will probably wind up switching the machine from a CPAP/APAP or bi-level machine to an ASV machine since the ASV machines can "trigger inhalations" and prevent the long chains of CAs from developing in the first place.

[Ayleone]

Ok, here's attempting to show 2 different nights...

[robysue]

Ayleone,

Your data looks really, really good. And the number of CAs scored by your machine is small enough where you really don't need to worry about them: On the first night you had 2 CAs scored in 9.55 hours of usage; on the second night you had 7 CAs scored in 9.5 of usage. That's less than one per hour on average, and you really don't need to worry about them.

Concentrate on learning how to sleep well with the machine and making sure you're good and comfortable in bed.

[Pugsy]

Ditto to what Robysue has said. Not enough centrals to worry about even if every single one of them was the real deal.

[Ayleone]

Thank you for the helpful information, that makes me feel better! I love all the information available here; knowing more about things makes them...less scary.

[Sleeper Agent]

Thank you for the helpful information, that makes me feel better! I love all the information available here; knowing more about things makes them...less scary.

AHI 1.26 is pretty much "optimal". If I could maintain that number, I would consider my treatment a success. Good job!

[Nick Danger]

Yeah - many of the people on the forum would consider killing (okay - I'm being figurative and hyperbolic here) to have those kinds of low numbers.

Congrats on really successful therapy!!