What affects the central apneas ?

[schuss]

Hello,
 
I am treated by PPC for apneas, and if this treatment decreases properly obstructive apneas, it does not correct the central apneas. I have noted that often these central apneas are due to the pressure of the PPC (see my post “[CPAP] Central-versus-obstructive")
Then, the question is for me to understand what affects these central apneas.
Because, without changing the settings of the PPC, I see changes in the rate of one night to the other. For example I have 14 central apneas per hour on average one night, and another night 2 central apneas per hour.
I also noticed that my central apneas are not distributed throughout the night, but still grouped at the end of the night, what makes that the calculated average is not really significant. So for an average calculated of 9.6 on a night, there was actually 30 central apneas in 25 minutes at the end of the night (for a total of 9 minutes apnea).
Do you have any idea what causes these variations? Is it possible that my device does not correctly detect central apneas? (It's an Resmed AirSense 10 Autoset)
 
Thanks to anyone who answers my question

[Hojo]

I'm with ya on trying to figure it out, I have no real reason to have CA, yet I have them.

[Beej]

Your body is in a dynamic state, constantly reacting to, and accommodating numerous factors, such as sleep, activity, diet, stress, illness, chronic medical conditions, etc. It is not surprising that it fluctuates night to night. Anything which reduces your brain's ability to function - ex sedative drugs or alcohol - will make it more difficult to respond to triggers to breathe.

The machine only identifies "clear airway", as it does not have all the electronic monitoring which properly classifies them. And a CPAP is the wrong machine to manage those; those are treated with an Adapto Servo Ventilater (ASV).

Some of the data towards the end of a sleep period may be sleep-wake junk, ie not actually events.

[SarcasticDave94]

First thing is that your current machine does not have the capability to detect central apnea, at least as I understand it. Your SleepyHead chart likely labels these as CA as in clear airway. Typically that can mean centrals but it doesn't always directly mean any clear airway is a central apnea event. If you're really dealing with Central Apneas, neither the CPAP or the BiPAP is the best tool to address centrals. That job would be an ASV machine like mine. The ASV I have has 4 settings to control both my obstructive and central apneas. It has to run a pressure high enough to keep obstructives away just like all other xPAP devices. It also has to keep pressures low enough so as to not induce a central. Going by my settings on the sidebar, my ASV has a base pressure of 9 which is called EPAP Min. EPAP has a range I set to go from 9 to max of 13. It then has Pressure Support I have as another range of 3-12. The algorithm in the ASV modifies mask pressure anywhere from as low as 9 EPAP for an exhale and up to 25 IPAP. EPAP 9-13 PLUS PS of 3-12 Equals IPAP of 12-25. Mine never gets to 25 IPAP at least not yet. My avg max is 19.2.

The rather amazing thing about an ASV is in the algorithm. I set its parameters, on a ResMed anyway, Min/Max EPAP (exhale pressure) and Min/Max PS (pressure support). As I alluded to above, the ASV takes those parameters as the orders to provide whatever it takes to minimize apneas, both obstructive and central, on a per-breath analysis. Like the Police song "Every Breath You Take" ASV is watching me.

[Doza]

I'm still trying to figure it out, too. Significant proportions of most nights' data are CAs in my charts.
I'm presuming it's nothing to worry about at this early stage (week 3) and they don't seem to marry up with other things like pressure, snores or leaks consistently.
I figure if nobody's responding to my charts in my one thread, then it must be ok.

[Apnea Infant]

Your body is in a dynamic state, constantly reacting to, and accommodating numerous factors, such as sleep, activity, diet, stress, illness, chronic medical conditions, etc. It is not surprising that it fluctuates night to night. Anything which reduces your brain's ability to function - ex sedative drugs or alcohol - will make it more difficult to respond to triggers to breathe.

The machine only identifies "clear airway", as it does not have all the electronic monitoring which properly classifies them. And a CPAP   is the wrong machine to manage those; those are treated with an Adapto Servo Ventilater (ASV).

Some of the data towards the end of a sleep period may be sleep-wake junk, ie not actually events.

Well said, Beej. 

Hello Schuss
 
I had a lot more centrals when I started therapy 6 months ago. I was concerned, the same as most of us are, due to the reasons possibly for them. Knowing your brain is not telling you to breath when your airway is clear appears frightening on the face of it. I still have some centrals but I do not believe they  are worth losing any sleep over.

However, was advised by the many wise and experienced here that pressure induced centrals at the start of CPAP therapy are not uncommon for most of us. It is indeed the case for me along with aerophagia, another nasty unwanted side effect. Also was informed here that most Sleep Professionals start us off with CPAP or APAP before moving onto BiLevels or ASV therapy, to treat central apnea if we really need it. You can read Half Asleep's journey to try to qualify for it.

I was advised to reduce EPR to as low as I could tolerate it as there is a belief that this causes centrals. I started with EPR at 3, slowly reduced to 2, then 1 and as of 3 nights ago, I turned it off. Sleep rider advised about 4-5 months ago (when I was at 16.8-14 cm H2O, EPR 3) that he saw my target as 11 cmH2O with no EPR. As ever, he is bang on the money!! Thank you SR. I am still recording AHI below 1 on this pressure. I took the changes real slow as I could not tolerate violent changes due to having to work 5 full days per week. Waiting for CPAP therapy had made me a zombie at work for 1.5 years at least, maybe more.

Hopefully you will discover what suits you sooner with the help on this forum.

The best to you......

AI

[SarcasticDave94]

I will throw this out for you, stealing a line from bonjour, "How do you feel after a nights sleep on CPAP?" If rested, even not adding to tiredness can count for now, you're likely dealing with newness to therapy CA situation lots of CPAP users have had to deal with. If you feel more tired after a nights sleep and use of CPAP, it is possible investigating into centrals and an ASV machine are actions to be considered. Consult with your sleep doctor about it, and keep posting here if we can assist in your success.

Dave

[schuss]

Thanks Beej for your response.
But about ASV, what do you think of the information found in the following links:
onlinecjc.ca/article/S0828-282X%2815%2901258-1/abstract
nejm.org/doi/full/10.1056/NEJMoa1506459
(It's because of this, that I'm looking for the factors impacting the central apneas, to avoid ASV)

[tmoody]

If you don't have systolic heart failure that article isn't especially relevant to your situation. Central apnea is still not well understood.

In my own case, I can document a fairly clear correlation between anxiety and CAs. When I'm under a lot of stress, the number of CAs each night goes up--even with ASV therapy. More than one or two alcoholic drinks is likely to increase them, not surprisingly since alcohol is a central nervous system depressant.

[Sleep2Snore]

If you read Resmeds info on what they define as a Central Apnea is a clear airway with no breathing taking place.
So in effect, the machine thinks you have a clear airway (How it does this I have no idea) but that is what it says on the European Clinicians Manual.  So in effect it is saying you have a clear airway, but you have either stopped breathing for a few seconds or you have died!
It also say the machine takes no action to try to get you to breath.  Very helpful if you stop breathing a lot during the night.

It explains it in every manual.
This is a fro her machine, but just some software changes for adjusting pressures etc.
In this case page six.
https://www.respshop.com/manuals/ResMed-...%20her.pdf