Is a Sudden Large Change in AHI Independent of Mask Type

[ChicagoGranny]

This is not a complete answer. I am trying to understand whether that 40 minutes wrecked your statistic for the night while the rest of the night was good.

I had events throughout the night, but there was a large cluster immediately preceding the worst period of AHI I've ever had in therapy. Between 1:15 a.m. and 1:45 a.m., I had a 29 events out of a total of 64 for the entire night. Between 1:40 a.m. and 2:15 a.m. my AHI was flat lined at 21 and then it began to recede. Not sure this is what you need.

Using the math to back into it, you must have used the machine 9.6 hours. Subtracting that problematic period (cluster of events), you used it 9.1 hours and had 35 (64 - 29) events. So for those 9.1 hours, your AHI was 3.6 - not too bad, but could still use improvement.

During that half-hour cluster, what did the leak line look like?

BTW, many of us set the maximum pressure to 20. That gives the machine room to work when our bodies need more pressure, and the machine will not raise the pressure unless it senses the need.

my AHI was flat lined at 21

Most of the regulars here don't pay much attention to the AHI line. I never turn it on in my SH charts. It's an index that requires interpretation - not easy to discuss. Best to just look at what events are occurring, at what time and what the leak line looks like.

[ChicagoGranny]

Comfortably Numb

Here is a good way to organize your charts - https://sleep.tnet.com/resources/sleepyhead/shorganize

[Comfortably Numb]

I had a much better result last night. Following the advice of Julie and others, I changed all of my settings back to what I was using with my N20. I then decided to focus on the one issue that I suspected to be the problem = pressure. With my machine set at full face and an EPR of 2, I changed the minimum pressure to 7 and the maximum to 12 (original setting with N20 had been 5-9).

My overall AHI was 0.93 (it was as high as 4 for a 30 minute period); I had a total of 5 events, only one of which was obstructive (0.13); I had 0 large leaks; my snore rate was near 0; and my maximum pressure hovered just below 12 (it doesn't appear to want any more). It seems at this point that my full face mask needed more pressure than did my nasal mask in order to produce similar results. The good news is that my large leaks have disappeared dramatically since switching to full face. I've seen where this is not usually the case with others. However, I believe that nearly all of my leakage with the N20 was from the mouth and the F20 has corrected that.

I'm going to stay at 7-12 for awhile and hopefully all will be settled. Thanks to everyone for your input!

[Comfortably Numb]

As I continue on using the full face mask with my new pressure settings (7-12), my AHI has come down to about 2.0 (it was usually less than 1.0 with nasal mask), I have virtually no leak rate at all, and I am sleeping "better" than with the nasal mask. A matter if interest is that my CA's have doubled with the full face mask and increased pressure. In the past, they were rarely present on the pie chart but now they occupy around 1/3 of the pie.

The only place that I can find my CA information on SleepyHead other than the pie chart is on the Statistics page under Clear Airways Index. It seems that CA's use to appear on my Event Flags graph but now I only see LL, OA, H, and RE. Have I accidentally done something to this graph to eliminate CA's from the Event Flags or are they not reported there as events? thanks

[Pugsy]

A matter if interest is that my CA's have doubled with the full face mask and increased pressure. In the past, they were rarely present on the pie chart but now they occupy around 1/3 of the pie.

The pie chart is a whole pie...guess what the pie chart would like like if you only had one central apnea the entire night...it would be entirely central/CA. Now what would the pie chart look like if you had 30 centrals over the entire night and nothing else...it would still be all central.

1/3 of something doesn't mean anything until you know the "something"....are we talking 1/3 of 3 or 1/3 of 30 or what????

The only place that I can find my CA information on SleepyHead other than the pie chart is on the Statistics page under Clear Airways Index. It seems that CA's use to appear on my Event Flags graph but now I only see LL, OA, H, and RE. Have I accidentally done something to this graph to eliminate CA's from the Event Flags or are they not reported there as events? thanks

You might have inadvertently turned off central/CA flagging in SleepHead reporting.
Look down at the bottom left side of all the graphs where the little menu with an arrow and says Flags is...click on it to expand the menu and make sure that CA is green and not red. Click on it to change the color.

If still not showing up try creating a new user profile in SleepyHead and importing all the SD card contents again and see if it shows up. If you had one....it should show up on the events graph.
Remember SleepyHead is Beta software and with Beta software it's a given that whacko things happen and we don't understand it.
Right now all my letters and words are gone on my OverView graphs...have no idea why they are gone and don't remember doing anything to them. No time to sort it out though and it's not a critical need...but just sharing with you that sometimes SH acts up and we don't have a clue why.

[Comfortably Numb]

You might have inadvertently turned off central/CA flagging in SleepHead reporting.
Look down at the bottom left side of all the graphs where the little menu with an arrow and says Flags is...click on it to expand the menu and make sure that CA is green and not red. Click on it to change the color.

You nailed it Pugsy, as usual. Somehow I had turned it off. I like your 1/3 analogy. What I meant to report is that I have evolved from a point where few if any CA slices of the pie appeared to a point where 1/3 of the pie is CA's. The numbers aren't high, but something has caused them to suddenly appear. My guess is increased pressure. Still nothing to worry about. Just an observation. thanks

[Pugsy]

My guess is increased pressure.

Might be the pressure but I tend to doubt it. You didn't really increase your pressure all that much and in most situations if you have centrals brought on by 11 cm of pressure 9 cm would also likely be doing it. It wouldn't be impossible for there to be a threshold where above it you have centrals brought on by pressure and below it you don't...but the odds are fairly slim against it especially since you aren't reporting large numbers. I would need to see some reports before offering up much in the way of WAGs (wild ass guesses) and at this point I don't see the need.

At this stage I would just sit back and watch things and give the body a chance to adjust to the new things you have tried.
They might be real centrals or they might be some awake breathing getting flagged by mistake. We could spend a lot of time and do a lot of hard work trying to figure out exactly what they are but the end result no matter what they might be would be to say "give the body some time to adjust to the new mask and new pressure and then see what is left over that needs evaluation".
I don't know about you but I am not too keen on doing massive work to figure out if a half a dozen centrals through the entire night are "real" or not unless there was some sort of pressing need and at this point there doesn't seem to be one.
And remember...it is normal to have a handful of real centrals and it doesn't mean anything bad is going on or that anything needs to be done about them anyway.

There is a lot of truth to the "give it time" thing. I learned that myself when I changed machines once and had to come up with some new settings. I picked something that worked well "some of the time" and not so well other parts of the time and I stayed at that same setting for 6 weeks and resisted urges to change something because last night's report wasn't what I wanted ...but the night before report was what I wanted...so which one did I want to believe.

At any rate after 6 weeks my AHI dropped a full 50% without changing a darn thing...from the 3 to 4 range to consistently below 2.0 without ever changing a thing. I would have a good night and then a bad night and then maybe 2 good nights in a row then maybe a bad night for a couple of nights but over the 6 weeks I saw a trend developing where I had more good nights than bad and by the end of the 6 weeks the "bad" nights were very rare.