What makes your curves disappear while the machine is clearly on?

[Crimson Nape]

Correct, I was saying that this option is inactive in the menu if you try to activate it while having an FFM declared. It only becomes available when you have one of the other masks declared. . . . At least on my S9 model. The accompanying manual states that this option is for the nasal and pillow mask.

[Sleepster]

Correct, I was saying that this option is inactive in the menu if you try to activate it while having an FFM declared.   It only becomes available when you have one of the other masks declared.   .  .  . At least on my S9 model.   The accompanying manual states that this option is for the nasal and pillow mask.

Hmmm... Doesn't seem to be true for my S9 VPAP Auto. I played with the settings and checked the manual.

[Crimson Nape]

Mine is the S9 Autoset.

[cathyf]

I see three issues
1, the Gap, turn smartstart off and see if that fixes it, It is remotely possible that the SD card wasn't firmly seated and vibrated out of and back into position.
2, the drop in flow rate to mee it looks positional.  There are mild arousal elements in your flowrate as well
3, your flow limits are high

1. I've never seen a gap like that before (and it didn't happen last night.) If it's not reproducible, no reason to believe the "change something and repeat" applies. The SD card vibrating out and back in makes lots of sense, though -- looking at the rest of the data it really looks like nothing happened except that data didn't get logged? Except why would the machine start a new session? And MyAir says 4 mask on/off events. (Myair which I hate with the heat of 1000 suns largely because of its obnoxious judgement that starting a new sleep session is a therapy failure.)

2. I'm having a lot of trouble figuring out the drops in flow rate and whether it's real or an artifact of leaks. One thing that I will say is that my breathing is noticeably shallower while wearing the cervical collar -- it stays very tightly between +15 and -15 with the collar, while without the collar it's more like +25 to -25.

3. For all going-on-7-years I've been on CPAP, "no flow limits" means "awake" and "asleep" means pretty much continuous significant flow limits. The only time that the machine doesn't calculate flow limits while I'm asleep is if I'm having an apnea or if the flow rate curve is so turbulent that the machine can't make out a shape at all. The cervical collar eliminates the chin tucking which creates the bursts of ridiculous flow limits, but the background of "asleep=flowLimit" is still there.