I went through my second, follow-up sleep study last night. I do, indeed, have a "nice, juicy" case of sleep apnea. While this session was very similar to the first (electrode hookups, etc) the major difference now was the use of a CPAC.
The CPAC is a mask-like device worn under the nose, similar to a Scuba breather, and attached to a small pump device. The whole thing straps to the head and is actually not that uncomfortable once you get used to it.
The pump draws air from the room, moves it through a humidifier to moisten it, and into the tube to the nose. The pressure creates a continuous airflow through the nose, because when I go into deep sleep the air intake gets way too low and not enough oxygen makes it into my lungs. This breather alleviates the problem. One interesting side-effect is that I can't open my mouth because the inrushing air will rush out the mouth - which is an interesting sensation to say the least.
The pressure is not so great that it's hard to deal with - you can breathe in and out through the nose normally. But it's still an odd sensation that will take getting used to.
So, I wore it all last night. I didn't sleep nearly as well as I had last week and woke up several times during the night. In fact, they said I only had one session of truly deep sleep because my mouth would open slightly and the air pressure change would wake me up. So I get to wear a chin strap to hold my mouth closed.
I should be receiving the mask sometime this week, and they'll set it up for me at home.