Increased pressure = increased AHI

kaiasgram wrote: And from what you're saying, raising the pressure would not do anything to stop the "centrals." Correct?

Correct.
The function of pressure is to maintain an open airway and prevent the collapse of the airway soft tissues which is why pressure is used to prevent obstructive sleep apnea events.

When we have a "central" be it the real deal or an awake central or a turn over in bed central...the airway is already fully open. There is no collapse of the airway tissues. Increasing pressure cannot make something more open than it already is.
If you used straight cpap pressure of 20...it would do nothing to prevent centrals from happening be they real or not.

Now people who have a predominance of the real deal centrals and get prescribed the ASV type of machines will get a burst of pressure to help ventilate or jump start the breathing mechanism. That is a totally different situation and the pressure delivery is different. Totally different discussion, machine, method of delivery and diagnosis.

Sorry for being a hog. The first 3 pics are from the 17th (pressure 15) and the second 5 pics are from the 28th (pressure 16).

I shouldn't be complaining with good numbers but my sleep has been really poor for a while now. Hopefully there is something obvious here.

Elle, The flow limitations are quite pronounced...at least it appears to me.
Wonder if this is a UARS type of situation?
If it were me I would be thinking of the minimum pressure and not the maximum pressure needing a little upward push to see if it helped reduced the flow limitations on the off chance that those flow limitations are possibly causing some little mini arousals and thus affecting sleep quality.

Hi Pugsy, I have trouble understanding "flow limitations". Here was something I thought was interesting from last night. Not sure why nothing showed on "flow" until morning?

Flow limitations are minor reductions in air flow that don't meet criteria for apnea or hyponea.
I have no idea what happened on your flow graph. That is weird.

I don't know that flow limitations are the cause of you not feeling as good as the numbers show but it is worth investigating.
Compare your flow limitations graph to mine and you will see why I say it is pretty ragged looking.

Wow, that is a huge difference. I will have to look back to see if it has been this way all along. Thanks Pugsy. I think I mentioned this before about how we kind of go through phases of good sleep and bad whether we are cpap users or not so I am not sure whether this is what is happening. I think I am noticing poorer sleep since the increase in pressure but maybe I just wasn't paying attention. Thanks again for your help.

Elle,

I agree with Pugsy. It looks like when your max was set to 15, you had good control of the events, but there was still some flow limitation going on, and that was what was causing the machine to max out for long periods of time.

Now my best guess is that the RT thinks increasing the max pressure is the way to even out your flow wave and eliminate the worst of those flow limitations. But if the increase in pressure is bothering you, it may be a wash and you might be better off moving the pressure back down to 15. And if you aren't feeling well in the morning, try seeing what a modest 1cm increase in the minimum pressure does to help those flow limitations.

There's also a lot of "ups and downs" in the wave flow for the night you had the max pressure set to 16, but I don't see the wave flow for the night with max pressure set to 15.

All those "ups and downs" in the wave flow for June 28 may be an indication that you were pretty restless during this night. Restlessness might be the cause of the increase in AHI as well. How soundly do you think you slept compared to normal? Much more restless? A bit more restless? About the same? A bit more soundly? A lot more soundly?

Boy Robysue, I am so impressed with how much you and Pugsy are able to understand this stuff. I have been on cpap for 6 years but only decided to try to learn about it when I acquired the S9 last December. It just might be too late for learning though (memory problems). It is fascinating to me to hear that restlessness will disrupt flow but it makes sense. I had never considered that.

I have been more restless lately and maybe I will just continue with the 16 pressure for a while longer to see if it is anxiety related and nothing to do with cpap. In general I sleep great with the occasional crappy night but it seems like more of those recently.

More info to cram into this pea brain. Hopefully one day it will click.