What is going on with all these centrals?

[CPAPforever]

I have lost 40 pounds and trying to get my BiPAP settings better. Was doing ok until last night. AHI=5.3 with all events CENTRAL. No obstructive events. I did reduce snoring significantly for the first time. My settings the previous night was 22/17 with pressure support of 4. I changed pressure support to 5 and IPAP to 23 and WHAM. Multiple central apneas. So I trade snoring for central apneas. Not good. Will set PS back to 4. My AHI with settings 22/17 PS=4 have been under 1.0 for over a year but with significant snoring. Never could get an adjustment that stopped snoring without introducing centrals.

I have attached what my typical nights have been with 22/17 PS=4 setting to compare.

[Pugsy]

Sometimes the PS setting (depending on the person and the setting) can cause the carbon dioxide levels in the blood to get out of whack. Higher PS causes too much carbon dioxide to wash out of the blood so the blood levels don't get high enough to cause the brain to send the breathe signal to its human. Carbon dioxide level in the blood is what drives the breathe signalling.

PS of 5 caused too much wash out of the carbon dioxide....so your brain didn't tell your body to breathe so you didn't and you get a truck load of centrals.
I have a friend who experiences the exact same thing but with a PS of 4 and with a PS of 3 rarely a central.
I have another friend who uses PS of 6 and has no centrals to speak of.

Another one of the many YMMV things that come with any cpap use.

So now you know you can't use PS of 5. You might get by with 4.5...dunno but if it were me I would be happy with 4 and leave PS alone.

If you want to address snoring more...a little more minimum EPAP is a safer choice for you.

[Miss Emerita]

Your machine allows you to raise the PS by just .02 cmH20 at a time, so give that a try. Stay at each new setting for at least a week. If you suddenly get a bunch of CAs, back down and stay there longer. At 4.8, I was getting a CAI of around 1 to 2 -- not horrible, so I stuck with it to keep flow limitations from messing with my sleep cycles. After two months, the CAI dropped to around .5 or lower. So it can take time.

[CPAPforever]

New settings last night: 17.6/23 ps=4 AHI=0.6. A much better night. I selected 17.6 for EPAP because previous report showed 95% of time I was at 17.8. 2 central events, 1 unknown, 0 obstructive. Snoring back (I was up 2AM to 4AM so not snorefree zone. Oh, well. I've have always had snoring with CPAP/BiPAP. Possible I cannot eliminate that. At least I don't have bed partner to disturb. Probably keep settings here. As I lose more weight, will monitor regularly to see if anything needs adjusting.

[Pugsy]

You need to understand what a 95% number actually is.

It is NOT where you were at for 95% of the time.

It is where you were AT OR BELOW for 95% of the time. The "or below" part of the definition is critical and people often don't understand it or even know aboutt.
95% numbers are easily skewed to the high side by a relatively short period of time at higher numbers. While it sometimes ends up being an effective baseline pressure for some people....for most people it is not necessarily a good base minimum to be using. It means using a lot more pressure all the time than might actually be needed.

[CPAPforever]

Thanks, got it. So 95% of the time I was from that number down to EPAP minimum. Maybe I need to drop EPAP min down more. The first report with all the centrals had median EPAP at 16.8. So I am bottoming out with EPAP min at 17. Probably should reduce EPAP min.

With lots of weight loss, can your sleep apnea still be bad due to saggy, loose tissue around throat and in mouth? I lost 40 pounds and then had Vertical Sleeve Gastrectomy last week so my weight will be dropping a lot over next few months.

[Pugsy]

Yes, while people sometimes find the OSA reduces with weight loss or sometimes pressure needs reduce. It's not something that is a guarantee because those airway tissues can also become saggier and floppier. I know of people needing more pressure.

You could probably safely reduce your EPAP minimum some but how much I don't know without working up to what you need..
My thought is if it were me I might try 15 and see what happens. I like nice round numbers.
It doesn't really hurt anything for you to use a higher than you might technically need minimum as long as you don't have any aerophagia issues and you are comfortable. I just didn't want you to think you just HAD to use that minimum because you didn't quite understand what the 95% number meant. Your choice and you get to play around with it as you wish. Now that you understand it a bit more it will just be better all the way around.

[chunkyfrog]

@cpapforever; what an adorable dog!

[palerider]

Thanks, got it. So 95% of the time I was from that number down to EPAP minimum. Maybe I need to drop EPAP min down more. The first report with all the centrals had median EPAP at 16.8. So I am bottoming out with EPAP min at 17. Probably should reduce EPAP min.

With lots of weight loss, can your sleep apnea still be bad due to saggy, loose tissue around throat and in mouth? I lost 40 pounds and then had Vertical Sleeve Gastrectomy last week so my weight will be dropping a lot over next few months.

Paying any attention, at all, to the statistical numbers is a road to nowhere.

What you need to do is look at the pressure curve throughout the night.