(09-23-2013, 02:53 PM)mdh235 Wrote: Central Apneas. I think it means your airway is clear, but you've stopped breathing for over 10 seconds.

Usually happens to me before I fall asleep and after I wake up but leave the machine on. I just ignore those.

(09-24-2013, 02:21 AM)archangle Wrote:

(09-23-2013, 02:53 PM)mdh235 Wrote: Central Apneas. I think it means your airway is clear, but you've stopped breathing for over 10 seconds.

Usually happens to me before I fall asleep and after I wake up but leave the machine on. I just ignore those.

Central apnea means you aren't trying to breathe. Generally, it's detected by a "chest effort belt" that sees your chest is trying to move.

The CPAP machine can't see this, so some of them send pulses of pressure down the hose and tries to tell if your airway is open. If you're not breathing and your airway is open, it assumes you are having a central apnea, but calls it a "clear airway" apnea.

Sometimes, you will be having a central apnea, but will also have a closed airway. The machine will call this an obstructive apnea, even though an in-lab sleep test would say "central."

Also, it's a bit tricky to tell whether the airway is open from the other end of the hose.

In general, I assume if it says "Clear Airway," it is a true central apnea. I assume that sometimes the machine may miss some centrals and classify them as "obstructive," but it's probably fairly accurate.

BTW, many older machine do not distinguish central from obstructive. Detecting central/clear airway is a newer feature. The data capable Philips Respironics PRS1 and ResMed S9 machines seem to do a pretty good job.

Healthy people may show centrals or obstructive "apneas" while still awake or between sleep and wakefulness. These aren't meaningful unless they're really bad or frequent.

(09-23-2013, 08:53 AM)Smitharbie Wrote: Can someone tell me what Clear Airway events are on Sleepyhead? It lists the Central Apneas, the Obstructive Apneas, and the Clear Airway events on the statistics,

(09-26-2013, 09:52 PM)Sleepster Wrote: It does!? I see only CA (clear airway, or sometimes also called central apneas) and OA.

OA means your airway is obstructed during an apnea, CA means your airway is not obstructed during an apnea.

(09-26-2013, 10:43 PM)Sleepster Wrote: Yes. I don't see the separate Central Apneas and Clear Airway apnea events mentioned by the OP.

(09-27-2013, 10:09 AM)Sleepster Wrote: What I'm saying is that SH does not report two separate types of apneas, one called clear airway and the other called central apnea.

It reports the OA index, the CA index, and the hypopnea index. The AHI is the sum of these three indices.