I've decided to post notes about the Belsomra (suvorexant) trial under a new thread with the name of the drug in its title to make it easier for future forum members to find using the search tools.
Night 1
The detailed instructions for Belsomra (suvorexant) say to take it about 30 minutes before going to bed. So I did that last night: Took the Belsomra about 30 minutes before I went to bed at around 1:45ish. And then didn't fall asleep right away because I wasn't particularly sleepy when I actually climbed in bed. I had put a timer on when I took the Belsomra for fear that I would get wrapped up in something, and I did need that timer to remind me to GO TO BED, so I'd gotten too wrapped up in the reading I was doing last night before bed. The reading was NOT on the computer, but it was something that was not "boring". So I need to work on choice of reading material. I also think that waiting the full 30 minutes may be a bit too long for me since I did (briefly) get sleepy about 10-15 minutes after taking the Belsomra. I also know I need to be much more draconian in saying, "Time to shut the computer down" at night----I didn't do that until about 12:55 last night.
But even though I didn't immediately fall asleep, the BiPap didn't bother me too much. Although I did get uncomfortable when the PR BiPAP Auto started its first "Hunt and peck" pressure increase for the night, and I turned Kaa OFF and back ON at that point, which was about 10 minutes after I first turned the machine on. And while I didn't fall asleep immediately after getting into bed, it didn't take me an exceptionally long to fall asleep, even with that early OFF/ON cycle for the machine. Subjectively I'd say it took a total of around 25-30 minutes to fall asleep. The SleepyHead data indicates that I was definitely sound asleep within 20-25 minutes of first turning Kaa on and about about 10-15 minutes after turning Kaa on for the second time at the beginning of the night. I felt a bit weird during this time, but the weirdness wasn't a bad kind of weirdness per se. Rather it's like I could feel the conscious (wake) side of my brain fighting back against the Belsomra by doing its darndest to keep thinking. There were some pretty strange daydream-type thoughts going through my mind. And my body felt very relaxed---spookily relaxed in fact---in a way that Ambien does NOT do for me.
Woke up this morning at around 8:45 this morning. Felt pretty decent and made the conscious decision to NOT repeat yesterday morning's mistake (written about in this thread: viewtopic/t105102/Sometimes-its-just-no ... sleep.html) I also had a really bad taste in my mouth when I woke up. Don't know if that's from the Belsomra or from allergies causing me to sleep with my mouth slighty open. (The leak line is pretty normal, but my tongue does a pretty good job of staying up on the top of my mouth even when my mouth opens up.) I was still very sleepy when I out of bed and I was a bit uncoordinated when walking down the stairs, but nothing alarming. Hubby had my first cup of coffee ready for me, and I perked up pretty well over breakfast and decided to get on cpaptalk. I'm not feeling particulary sleepy right now, but I'm also aware that I'm still waking up.
And what happened between falling asleep and waking up?
The data indicates that I clearly woke up 4 times, which is fewer than my worst nights on Ambien, but about the same as my best nights on Ambien; I can clearly remember 1 wake and I sort of remember 1-2 other wake(s). (I normally remember 2-3 of my far more numerous wakes.) At the first wake I was uncomfortable enough with Kaa to get up and go to the bathroom; the other wake(s) I remember are only vaguely remembered, and I can't pin point which ones they are.
The really good news is that I had a PAP session that lasted 2:27 in the middle of the night! This was the second session for the night, and it's somewhat unusal for my second session to be the longest of the night. The last time I had a session that was over 2 hours long was a week ago on April 6; that one lasted 2:10.
And last night I had two other single sessions that were pretty long for me as well: The first session after I got to sleep lasted 1:12, the third session for the night lasted 1:34. After that third session I had a 27 minute session followed by a 54 minute session separated by a very short wake.
The AHI for the night is 1.60. There were 4 Hs and 7 OAs scored during the night, with 4 of the OAs occuring about 10 minutes before I turned the machine OFF and back ON at around 5:46 this morning. Don't know what happened here. Maybe REM? Maybe some post arousal SWJ since there's a big breath right before the first apnea is scored? At any rate, it's not enough to worry about. Here's a picture of that cluster close up:

Overall? I think it last night is a promising beginning. We shall see what happens as my trial continues.