Please help define "Clear Airway apnea"

Hi,

I have finally gotten my Mac pro fixed and sleepy head loaded. I've got a few questions that I can't seem to find any info on;

What is a clear airway (apnea?) Sorry I do not have the computer in front of me for the exact term but it is the CA in the event summary.

Is this a Central?

How does it differ from a hypo?

Thanks in advance!

Day_Dreamer wrote:Hi,

I have finally gotten my Mac pro fixed and sleepy head loaded. I've got a few questions that I can't seem to find any info on;

What is a clear airway (apnea?) Sorry I do not have the computer in front of me for the exact term but it is the CA in the event summary.

Is this a Central?

How does it differ from a hypo?

Thanks in advance!

Clear airway event = airway is open but no breathing. A clear airway event can be a true central apnea (if you're actually asleep), or could just be a pause in breathing (from turning over, yawning, transitioning from sleep to wake, etc.) so not a true central apnea. Hypopnea does involve partial airway obstruction, and Obstructive is complete airway obstruction.

The so-called Clear Airway Apnea is the condition in which the patient stops breathing but the airway remains open.
If this happens in a sleep lab, the instrumentation will allow for detecting respiratory effort. In the lack of respiratory effort, the event is a central apnea. Without the respiratory effort information, the CPAP machine can't determine it to be one, so it is labeled CA.

Some (and maybe most) CPAP machines create pressure pulses to help distinguish between obstructive events (airway is closed) and clear airway events (airway is open). "Brick" machines that don't produce efficacy data likely don't.

Day_Dreamer wrote:Hi,

I have finally gotten my Mac pro fixed and sleepy head loaded. I've got a few questions that I can't seem to find any info on;

What is a clear airway (apnea?) Sorry I do not have the computer in front of me for the exact term but it is the CA in the event summary.

Is this a Central?

Yep. It means your airway is open, and you're capable of breathing, but you don't. It's a crossed signal between your brain and your respiratory system.

How does it differ from a hypo?

Thanks in advance!

A hypopnea is recorded when your breathing is shallow, so it would indicate a partially open airway.

Hope that helps.

As always

thanks everyone!!!

Day_Dreamer wrote:Hi,

I have finally gotten my Mac pro fixed and sleepy head loaded. I've got a few questions that I can't seem to find any info on;

What is a clear airway (apnea?) Sorry I do not have the computer in front of me for the exact term but it is the CA in the event summary.

Is this a Central?

How does it differ from a hypo?

Thanks in advance!

for this, and other questions, there's a wiki that will be very helpful.

palerider wrote:[
for this, and other questions, there's a wiki that will be very helpful.

.

Hi Pale rider could you please provide my a link to that?

Yesterday when I knew the proper term, I searched Wiki, Searched the forum, checked the CPAP definitions, searched yahoo. I was sick yesterday with 101 temp, so maybe my brain was not working correctly

Thanks

Day_Dreamer wrote:

palerider wrote:[
for this, and other questions, there's a wiki that will be very helpful.

.

Hi Pale rider could you please provide my a link to that?

Yesterday when I knew the proper term, I searched Wiki, Searched the forum, checked the CPAP definitions, searched yahoo. I was sick yesterday with 101 temp, so maybe my brain was not working correctly

Thanks

funny, had a 101 fever monday... *lol*

I apologize, I thought that was in the wiki, but I can't find it either. a good discussion of centrals is in that other wiki on that other board, but nothing that I saw equating CA with centrals.

sleepyhead's own wiki may come in handy too: http://sleepyhead.sourceforge.net/wiki/ ... e=Glossary

mine you, I'm not trying to discourage your asking questions, just trying to point out resources so you can find answers without having to wait for someone to respond

[/quote]

I'm not trying to discourage your asking questions, just trying to point out resources so you can find answers without having to wait for someone to respond [/quote]


Thanks

I think the distinction that JDS74 pointed out is an important one: we really have no way of knowing whether clear airway events detected by our machines are truly centrals. This is something I did not fully appreciate when I started out with CPAP -- sometimes for a variety of reasons we might have a pause in breathing. Without a PSG there's just no way to know whether these are true centrals caused by a lack of a signal from our brain stems or are a result of arousals, movement, etc. If we wrongly assume that these are all centrals, we might make unnecessary changes to our therapy trying to resolve them when they are nothing more than sleep-wake junk.

A "central" apnea means your body is not trying to breathe. It's measured in an in-lab sleep study by a "chest effort" belt that sees that your body is trying to inflate your lungs.

A "clear airway" indication means the CPAP machine thinks your airway has not closed off. It attempts to determine this by various means, but it's not 100% accurate.

Sometimes you may have a closed off airway, but are not trying to breathe. This is a central apnea, but the CPAP machine will not see a clear airway apnea.

I think you can pretty safely assume a clear airway apnea is a central apnea, but you can't assume all central apneas show up as clear airway apneas.

In the end, I don't think the difference matters that much. Even if you have a central apnea, but it doesn't show up as a clear airway apnea, it still shows up as an apnea. Centrals aren't necessarily more harmful than obstructives, they're just harder to eliminate. You don't need to worry about the difference that much unless you have enough apneas to be a problem and you can't figure out how to eliminate them.

archangle wrote:In the end, I don't think the difference matters that much. Even if you have a central apnea, but it doesn't show up as a clear airway apnea, it still shows up as an apnea. Centrals aren't necessarily more harmful than obstructives, they're just harder to eliminate. You don't need to worry about the difference that much unless you have enough apneas to be a problem and you can't figure out how to eliminate them.

The real issue is, in my opinion, exactly the opposite of the one you seem to be addressing. It's not that centrals are being missed, but that things are being falsely flagged as centrals when they may in fact be pauses in breathing due to arousals, movement, etc rather than central nervous system issues. If one assumes that all clear airway events are centrals, he may falsely believe that he has a complex apnea problem or pressure-induced centrals when the real issue is sleep hygiene or medication or any of a number of things that can affect sleep and cause CA's that are not CNS-related.

The Latinist wrote:

archangle wrote:In, he may falsely believe that he has a complex apnea problem or pressure-induced centrals when the real issue is sleep hygiene or medication or any of a number of things that can affect sleep and cause CA's that are not CNS-related.

yes

I recently adjusted my pressure to combat pressure induced Centrals. After loading Sleepy head, I can now see these events occur also at lower pressure 7-8 range and as such are probably not true CA's

The Latinist wrote:

archangle wrote:In the end, I don't think the difference matters that much. Even if you have a central apnea, but it doesn't show up as a clear airway apnea, it still shows up as an apnea. Centrals aren't necessarily more harmful than obstructives, they're just harder to eliminate. You don't need to worry about the difference that much unless you have enough apneas to be a problem and you can't figure out how to eliminate them.

The real issue is, in my opinion, exactly the opposite of the one you seem to be addressing. It's not that centrals are being missed, but that things are being falsely flagged as centrals when they may in fact be pauses in breathing due to arousals, movement, etc rather than central nervous system issues. If one assumes that all clear airway events are centrals, he may falsely believe that he has a complex apnea problem or pressure-induced centrals when the real issue is sleep hygiene or medication or any of a number of things that can affect sleep and cause CA's that are not CNS-related.

a cecessation of breathing, when no respiratory effort is put forth is the definition of a central... there's no, to my knowledge, distinction between doing it because of a co2 imbalance or whatever, or simply just not breathing, or holding your breath. unless one is tossing and turning in one's sleep such that fitting a fan blade to ones feet could cool the room, there won't be enough 'movement induced clear airway apneas' if you will, to matter.

The Latinist wrote: The real issue is, in my opinion, exactly the opposite of the one you seem to be addressing. It's not that centrals are being missed, but that things are being falsely flagged as centrals when they may in fact be pauses in breathing due to arousals, movement, etc rather than central nervous system issues. If one assumes that all clear airway events are centrals, he may falsely believe that he has a complex apnea problem or pressure-induced centrals when the real issue is sleep hygiene or medication or any of a number of things that can affect sleep and cause CA's that are not CNS-related.

If you have an apnea, and no respiratory effort, it's a "central apnea," by definition, no matter what the cause. Presumably, if your airway is clear, and you're not breathing there is no respiratory effort.

If you are not asleep, it's not an "apnea," whether it's central or obstructive. The CPAP machine cannot tell you're awake, so it will score "false" apneas when you're awake. Let's call that a "wake apnea." Whether it calls it central or obstructive doesn't seem to me to matter a lot. You really shouldn't be having a lot of "wake apneas, " but it's a good idea to look at your airflow waveforms and see how long the "apneas" are. Presumably "wake apneas" don't tend to last too long.

CPAP probably doesn't have much effect on "wake apneas," either.

For your heath, the number, duration, and severity of the apneas is probably what matters. Central vs. obstructive mostly matters in terms of figuring out how to eliminate the apneas.