Need explanation about central apnea index

[kvck]

Hi everyone,

I have been using my Resmed S9 for almost 9 months. My average pressure is around 6.2, average leakege is 3 liters, average sleep duration is 8 hours. Total apnea index is 0.3, AI is 0.2 and CAI is 0.2. As a sidenote, my ERP is 2.

However, in the last days, I noticed an increase of CAI to 0.4-0.6 range but not higher than this range. My other parameters are still around the 9-month average.

I wonder if someone could explain me when CAI is a concern (a threshold?) and could tell me how my level is. Thanks for the replies.

I almost every day wake up at around 4am to 6am and stay awake around 5 minutes, then go back to sleep. I wonder if there could be any correlation between CAI and my sleep disturbances, which are most of the time happen at the end of REMs.

[Dog Slobber]

Centrals in the 0.4-0.6 range are not a concern. A little volatility over a few days are not a concern either.

[ChicagoGranny]

happen at the end of REM

How do you know you have been in REM?

[kvck]

happen at the end of REM

How do you know you have been in REM?

I am using Garmin watch, which seems to be pretty precise. I see the REMs along with awakes via the watch.

[kvck]

Centrals in the 0.4-0.6 range are not a concern. A little volatility over a few days are not a concern either.

Though low, could they still result with awakes? I am trying to figure out what cause the awakes in the morning.

[Dog Slobber]

Centrals in the 0.4-0.6 range are not a concern. A little volatility over a few days are not a concern either.

Though low, could they still result with awakes? I am trying to figure out what cause the awakes in the morning.

I would guess they are more likely because of awakes.

[Pugsy]

It's normal to have a few centrals during the night.
Like it is normal to have a central apnea when transitioning from awake to asleep...also called sleep onset centrals.
It is also normal to wake up after REM stage sleep cycle is completed....entirely normal. Most of the time we aren't awake long enough to formulate a memory of the awakening but sometimes we don't roll over and go right back to sleep.

So a few wake ups during the night are normal and not necessarily caused by anything that is cpap or apnea related.
Google "sleep stages" and look at the normal hypnograms for various sleep stages and there's always a wake up after REM.

What basis does the Garmin device use to establish sleep stage???? Any electrodes to the face or head to measure EEG brain waves???? If not it doesn't have any way to actually know if you are asleep or not...much less sleep stages.
It might make educated guesses but it can't collect real data needed for confirmation without EEG leads.

http://freecpapadvice.com/sleepyhead-free-software
Using OSCAR software (based off SleepyHead) you can actually look at the flow rate and figure out if your centrals are real asleep centrals or arousal/awake centrals. If you aren't asleep they simply don't matter.
OSCAR https://www.sleepfiles.com/OSCAR/
http://www.apneaboard.com/wiki/index.ph ... stallation
http://www.apneaboard.com/wiki/index.ph ... rpretation

All that said...even if every single one of your Centrals were asleep centrals you aren't having enough of them to worry about. I suspect that a few of your centrals got flagged AFTER and arousal though and thus reflect the awake breathing false positive pause in breathing and not the cause of the awakening.

[palerider]

I wonder if someone could explain me when CAI is a concern (a threshold?) and could tell me how my level is. Thanks for the replies.

The only time that centrals are a concern is when you're having so many that your oxygen levels start dropping, and the only way you can find that out is if you're wearing an oximeter.

[kvck]

Centrals in the 0.4-0.6 range are not a concern. A little volatility over a few days are not a concern either.

Though low, could they still result with awakes? I am trying to figure out what cause the awakes in the morning.

I would guess they are more likely because of awakes.

I got your point now. Thanka for your reply.

[ChicagoGranny]

I almost every day wake up at around 4am to 6am and stay awake around 5 minutes,

If that is your only complaint, you should consider yourself blessed. It's perfectly normal to awaken several times during the night and fall back to sleep in a short time. Five minutes is good.

I am using Garmin watch, which seems to be pretty precise. I see the REMs along with awakes via the watch.

Gramps and I used several FitBit models. Their algorithm to guesstimate sleep stages by wrist motion is a wild guess. Apple Watch refuses to include sleep stages because they know, like Pugsy said, EEG readings are needed to determine sleep stages.

What you are seeing as Centrals, may just be what is slangily known as SWJ or Sleep-Wake-Junk. They are not really Centrals. The machine does a poor job of classifying events when we are awake of slipping in and out of sleep.

If you are using OSCAR, clicking on the Events tab will bring up a list of Centrals including their length. Yours are probably of short duration. If you see any 20+ seconds long, it could be a problem.

[kvck]

It's normal to have a few centrals during the night.
Like it is normal to have a central apnea when transitioning from awake to asleep...also called sleep onset centrals.
It is also normal to wake up after REM stage sleep cycle is completed....entirely normal. Most of the time we aren't awake long enough to formulate a memory of the awakening but sometimes we don't roll over and go right back to sleep.

So a few wake ups during the night are normal and not necessarily caused by anything that is cpap or apnea related.
Google "sleep stages" and look at the normal hypnograms for various sleep stages and there's always a wake up after REM.

What basis does the Garmin device use to establish sleep stage???? Any electrodes to the face or head to measure EEG brain waves???? If not it doesn't have any way to actually know if you are asleep or not...much less sleep stages.
It might make educated guesses but it can't collect real data needed for confirmation without EEG leads.

http://freecpapadvice.com/sleepyhead-free-software
Using OSCAR software (based off SleepyHead) you can actually look at the flow rate and figure out if your centrals are real asleep centrals or arousal/awake centrals. If you aren't asleep they simply don't matter.
OSCAR https://www.sleepfiles.com/OSCAR/
http://www.apneaboard.com/wiki/index.ph ... stallation
http://www.apneaboard.com/wiki/index.ph ... rpretation

All that said...even if every single one of your Centrals were asleep centrals you aren't having enough of them to worry about. I suspect that a few of your centrals got flagged AFTER and arousal though and thus reflect the awake breathing false positive pause in breathing and not the cause of the awakening.

Thanks for the detailed answer. I will check Oscar. About Garmin, I actually don't know the method or how it works but what I am trying to solve is my regular sleep disturbance. The watch may be not a good indicator but what I noticed and correlated that when I wake up, I look at the watch, then in the morning I look at Garmin and see the same time of REM ends as per the watch. Trying to make sense on this correlation.

However, apart from that I got the whole point about the mechanism of CAs. Thanks again.

[kvck]

I almost every day wake up at around 4am to 6am and stay awake around 5 minutes,

If that is your only complaint, you should consider yourself blessed. It's perfectly normal to awaken several times during the night and fall back to sleep in a short time. Five minutes is good.

I am using Garmin watch, which seems to be pretty precise. I see the REMs along with awakes via the watch.

Gramps and I used several FitBit models. Their algorithm to guesstimate sleep stages by wrist motion is a wild guess. Apple Watch refuses to include sleep stages because they know, like Pugsy said, EEG readings are needed to determine sleep stages.

What you are seeing as Centrals, may just be what is slangily known as SWJ or Sleep-Wake-Junk. They are not really Centrals. The machine does a poor job of classifying events when we are awake of slipping in and out of sleep.

If you are using OSCAR, clicking on the Events tab will bring up a list of Centrals including their length. Yours are probably of short duration. If you see any 20+ seconds long, it could be a problem.

It is clear now. Wow, it is such an info tsunami appreciated. I will check Oscar and use Garmin for only to count steps

[palerider]

Thanks for the detailed answer. I will check Oscar. About Garmin, I actually don't know the method or how it works but what I am trying to solve is my regular sleep disturbance.

"regular sleep disturbance" is not something you should be trying to fix, since as mentioned, they're completely normal.

The only thing that's possibly somewhat abnormal is remembering the waking between sleep stages.

looking for info between sleep stages can provide you much more information.

https://www.verywellhealth.com/the-four ... ep-2795920

[ChicagoGranny]

It is clear now.

If you have a dead horse you want beaten, you've come to the right place.

[zonker]

It is clear now.

If you have a dead horse you want beaten, you've come to the right place.

thanks! i've been holding on to this one for seven months.