Interpreting central events

Interesting discussion. From the experience of the community, can a CPAP pressure set slightly too high result in both CA's and Cheyne-Stokes breathing?

Thanks,

PAJerry wrote:Interesting discussion. From the experience of the community, can a CPAP pressure set slightly too high result in both CA's and Cheyne-Stokes breathing?

Yes, in a small percentage of CPAP users it can. When this happen we normally would see the incidence of centrals occur at a steady rate throughout the night which is not what we see on this report. So I am not so sure that is what we see going on here. Also the pressure doesn't have to be an extremely high pressure...just for a certain person the pressure can induce centrals. Sometimes they go away..sometimes not and a different machine might be in order.

Something happened starting at 4 AM for the OP here. We don't know what. The report is not typical for pressure induced centrals though. I mentioned my last thought about it as a way out on the limb idea if nothing else could explain it. The one hard fast rule that I have learned about cpap therapy is that there are no hard fast rules.

An occasional episode of CSR can be entirely normal along with its perhaps a handful of centrals. I see it from time to time myself. It is when they take over the night that we worry. While the 4 AM ugly hour or so sure looks like it could be CSR, it certainly doesn't take over the night. If it did the suggestion would be simply notify the doctor. This one is more puzzling as to what is happening to cause this response.

Thanks, Pugsy. Good heavens, there is a lot to learn.

birdie22 wrote:Hi,

archangle wrote:What is your CPAP pressure?

How long do the "Central apnea" events last?

My CPAP pressure is set to 10.

Central events typically last for 1 to few hours (see my post above). Each event lasts around 18 seconds, on average.

Thank you

Well, at least the centrals don't last very long. If they were lasting 40 seconds or so, it would be a lot more worrying.

There's a theory that CPAP causes centrals because your lungs are full of air and your blood has good enough O2/CO2 concentrations that you don't really need to breath for a while. Try this experiment. Inhale deeply and then hold your breath for 20 seconds or so. See how badly you feel you need to take a breath. Now, take a deep breath, blow as much air as you can out, then hold your breath for 20 seconds.

That doesn't mean your short centrals are "OK," but I'd sure be more concerned about long duration centrals. I'd hate to see someone panic about having a high count of machine scored "centrals" without really looking at it. Be sure someone really looks at your data before doing something like putting you on a bilevel or ASV machine.

The older definition of "central apnea" required you to stop breathing for 10 seconds AND have a drop in blood O2 concentration or an EEG "arousal." Lots of people are forgetting to mention the O2/EEG requirement these days. I suspect that profit motive may have a lot to do with this change in usage of the term. Your CPAP machine can not detect a "real" central apnea conclusively. If you stop breathing for a long enough time, you can be pretty sure your O2 level dropped. If it's only 20 seconds, maybe, maybe not.

Pugsy wrote:Is this report typical for you? Have you had reports for all night that look like the first half or do you always have this many centrals or more?

This is not always like that. When central events happen, they are usually a little bit less crowded. But few times, this is even worse.
And yes, there are few nights that look like the first half, but they are minority.

Pugsy wrote:Do you normally sleep on your back? Is it possible that sleeping on your back is a factor in the wild half of the night?

As far as I know, I don't sleep on my back.
My sleep is usually not very deep during these hours and I can remember flipping from one side to the other.

Pugsy wrote:If you consistently have long periods of time where these many centrals are present and you cannot isolate a causative factor and you can't reduce them...you may need to discuss a different type of machine.

Thank you very much for advice Pugsy. It is very much appreciated. I will definitely talk to my doctor, and I'm considering lowering the pressure a bit.

You had the home study didn't you? You know it is possible that if you had been in a regular sleep lab with tech in attendance some of those centrals might not have been scored as centrals because tech would have immediate access to your EEG to see if you were really asleep. If you weren't asleep or even partially awake tech would have evaluated thoracic effort and EEG before scoring. I would sure keep the doctor in the loop as your reports as they are now are really unusual and we don't know why.

Since the centrals tend to cluster, this may be a result of the transition between wakefulness and sleep (and back). Central apneas tend occur during such transitions.