Why did my AHI shoot way up?

[dk2011]

Notice the AHI graph below.  Notice the difference between my first 6 hr 42 mins compared to the last 2 hr 40 minutes last night!

The first 6 hr 42 mins last night was looking great and was at an average AHI around 2!

Then I remember waking up, and going back to sleep.  Then my AHI shot up to over 20 at one point dragging my night's average AHI to 6.06.  I think I had switched to sleeping on my side if I remember right.

Can somebody help me figure out what happened and why?

I'm still new guys and learning as much as I can. Thanks in advance for help!

UPDATE:  I just realized I changed the Flex setting from "1" the first part of the night to "3" when I was briefly awake.  Why would the Flex setting cause such drastic problems?  It sounds like I need to turn off Flex completely then?

[Gideon]

If I'm reading your charts correctly I don't think you were asleep between 6:15 and 7:45, at least you were tossing and turning.  (Note the difference in your flow chart and your tidal volume between that interval and your first session.)

Also of note is that your pressure was notably lower during the second session.

This is looking at 1 chart but I think you would do a bit better by setting your range to 8-12 vs your current 6-12.  This will allow your PR machine to react quicker to reach therapeutic pressures when obstructive events occur.

Also you had a marked increase in CA events in the second session, this could correlate with a bunch of toss and turns as we all tend to hold our breath when we toss and turn and this breath holding is frequently misinterpreted as CA events.  CPAPs will not increase pressure when CA events are detected.


Fred

[Ron AKA]

Notice the AHI graph below.  Notice the difference between my first 6 hr 42 mins compared to the last 2 hr 40 minutes last night!

The first 6 hr 42 mins last night was looking great and was at an average AHI around 2!

Then I remember waking up, and going back to sleep.  Then my AHI shot up to over 20 at one point dragging my night's average AHI to 6.06.  I think I had switched to sleeping on my side if I remember right.

Can somebody help me figure out what happened and why?

I'm still new guys and learning as much as I can. Thanks in advance for help!

UPDATE:  I just realized I changed the Flex setting from "1" the first part of the night to "3" when I was briefly awake.  Why would the Flex setting cause such drastic problems?  It sounds like I need to turn off Flex completely then?

The big difference I see is that the second half had lower pressures. Your pressure and EPAP pressure readings suggest you did not make an change to the Flex program. The differential (between the red and green trace) seems to be the same. There does appear to be a beginning Ramp used in the second half of the night, but not the first.

Suggestions:
For now I would leave the Flex at 3. You could consider increasing your minimum pressure from 6 to 8, and the maximum from 12 to 13. If you want to use Ramp there is a Ramp initial set pressure that you can set. If you revise your minimum to 8, I would suggest 6 as your ramp pressure start. If you leave minimum at 6 and keep the ramp, you could set the ramp initial pressure at 5.