Can Clear Airway Apnea not be Central Apnea?

[tomko44]

I just started using my Bi-PAP machine 11 days ago and most of my Apneas are "Clear Airway" per Restronics. I have no detectable snore, but I know that at times my mouth is opening slightly. I think that that is being detected as Clear Airway. Is that possible? Thanks!

[trish6hundred]

Hi tomko44, First, Welcome! to the forum.! I don't know the answer to your question but just keep checkin' back and someone will be able to help you, just hang in there. I do have a suggestion for you though, if you find yourself mouth-breathing, you might want to try a chinstrap to help with that. Best of luck to you with your CPAP therapy

[tomko44]

Hi tomko44, First, Welcome! to the forum.! I don't know the answer to your question but just keep checkin' back and someone will be able to help you, just hang in there. I do have a suggestion for you though, if you find yourself mouth-breathing, you might want to try a chinstrap to help with that. Best of luck to you with your CPAP therapy

I tried one that was in expensive and it slips too much. I just found one that attaches to my headgear and will give that a try. If not, I may have to switch to a full mask instead of a nasal mask.

[Sleepster]

Hello tomko44!

I also started getting a lot of CA's when I switched to a BiPAP. Recently there was an article posted here describing some research results that indicated that this does occur in lots of other folks, too.

The solution for me was to lower the pressure. This was done by my doctor, so I'd advise you to let your doctor know what's going on, too. The solution for you may be different. Also, you'll want to wait a few days and see if it goes down by itself.

There is, strictly speaking, a difference between a clear-airway apnea and a true central apnea. Your CPAP machine uses a flow meter to determine when you've stopped breathing. It then sends pressure pulses down your airway in an attempt to determine if it's obstructed or clear. If obstructive, it scores an OA. If clear, it scores a CA.

(A true central apnea is characterized by a lack of effort to breathe, something a mere CPAP machine can't determine, but the jargon is to refer to these CA's as central apneas anyway, even though the the term clear-airway apnea is probably a better characterization. None of this is really relevant to this discussion, anyway, unless you were diagnosed with central apnea or mixed apnea. If you were diagnosed with simple obstructive apnea, then these CA's you're experiencing are called CPAP-induced central apneas. The thinking is that the extra pressure from the CPAP machine loads your lungs with oxygen, which in turn raises your blood oxygen level, which in turn causes your brain to tell your lungs to stop breathing. Hence, lowering the pressure usually fixes the problem. But lowering the pressure can cause an increase in OA's, so sometimes it's a balancing act.)

I doubt that your mouth-leaking is the cause of your elevated CA index, but it's easy enough to figure out. Look at the CA's and see if they coincide with periods of time when the leak rate is too high. I doubt the machine would score a CA in these cases, but I really don't know. Hopefully your new chinstrap will stay put and stop the mouth-leaking. Then you'll have one less variable to worry about.

Another thing you can do is zoom in on the Flowrate graph and see just how long these CA's last. They have to last for at least 10 seconds to count. If they don't last much longer than 10 seconds they're far less damaging than if they last significantly longer.

What is your AHI? Your OA, CA, and hypopnea indices?

Were you on a CPAP before the BiPAP? If so, what was your pressure and your AHI?

What's the reason they put you on a BiPAP rather than a CPAP?

[zonk]

Whats the AHI, leak and most importantly how you feel?
Did your titrations shows any centrals?
It is not uncommon to have some apnea events flagged as we,re trying to fall sleep as the machine cannot tell if we,re awake or sleep and those events would not be flagged in a sleep lab situation.
IMO we need to get a decent and uninterrupted sleep before we can start worrying about anything else.

[zonk]

Recently there was an article posted here describing some research results that indicated that this does occur in lots of other folks, too.

http://www.apneaboard.com/forums/Thread-...ring-Sleep

[tomko44]

Hello tomko44!

I also started getting a lot of CA's when I switched to a BiPAP. Recently there was an article posted here describing some research results that indicated that this does occur in lots of other folks, too.

The solution for me was to lower the pressure. This was done by my doctor, so I'd advise you to let your doctor know what's going on, too. The solution for you may be different. Also, you'll want to wait a few days and see if it goes down by itself.

There is, strictly speaking, a difference between a clear-airway apnea and a true central apnea. Your CPAP machine uses a flow meter to determine when you've stopped breathing. It then sends pressure pulses down your airway in an attempt to determine if it's obstructed or clear. If obstructive, it scores an OA. If clear, it scores a CA.

(A true central apnea is characterized by a lack of effort to breathe, something a mere CPAP machine can't determine, but the jargon is to refer to these CA's as central apneas anyway, even though the the term clear-airway apnea is probably a better characterization. None of this is really relevant to this discussion, anyway, unless you were diagnosed with central apnea or mixed apnea. If you were diagnosed with simple obstructive apnea, then these CA's you're experiencing are called CPAP-induced central apneas. The thinking is that the extra pressure from the CPAP machine loads your lungs with oxygen, which in turn raises your blood oxygen level, which in turn causes your brain to tell your lungs to stop breathing. Hence, lowering the pressure usually fixes the problem. But lowering the pressure can cause an increase in OA's, so sometimes it's a balancing act.)

I doubt that your mouth-leaking is the cause of your elevated CA index, but it's easy enough to figure out. Look at the CA's and see if they coincide with periods of time when the leak rate is too high. I doubt the machine would score a CA in these cases, but I really don't know. Hopefully your new chinstrap will stay put and stop the mouth-leaking. Then you'll have one less variable to worry about.

Another thing you can do is zoom in on the Flowrate graph and see just how long these CA's last. They have to last for at least 10 seconds to count. If they don't last much longer than 10 seconds they're far less damaging than if they last significantly longer.

What is your AHI? Your OA, CA, and hypopnea indices?

Were you on a CPAP before the BiPAP? If so, what was your pressure and your AHI?

What's the reason they put you on a BiPAP rather than a CPAP?

Here is what I have from Sleepyhead for lat night:

Hyponea .29
Obstructive 1.45
Clear Airway 3.62
PB/SCR .51%

The Hyponeas seem to always coincide with the CA

Just started 11 days ago and they put me on Max pressure on the BiPAP (25/21). I am using the Mirage FX and I know it is technically not rated for 25.

I was told in my sleep study my AHI was 109.

[PaulaO2]

With a pressure that high, I would not be surprised if you are having central apnea events. Don't docs believe in slowly introducing higher pressures?!?

Since you have been only using it for 11 days, I suggest you contact the sleep doc.

[zonk]

Just started 11 days ago and they put me on Max pressure on the BiPAP (25/21).

This is very high pressure and its going take some time finding the right mask. Its essential to find a mask that is comfortable to wear and keep all night with less leak as possible - large leaks can affect sleep architecture and the accuracy of data. If one mask don,t work for you - keep trying and returning back to DME within 30 days as its allowed by manufacturers.
I think you need to start a new thread what mask works for high pressure so folk on high pressure can help with their suggestion.

[JJJ]

I think you need to start a new thread what mask works for high pressure so folk on high pressure can help with their suggestion.

It would be great if there was a list of all masks and their pressure ratings.