CPAP vs O2, surgery and fog

I just had my appendix removed via laproscopy (not fun), and noticed something when I awoke from anesthesia.
No cognitive fog or headache. (everywhere else hurt of course, especially the chopped area.)
I have only had around 6 totally fog free days since starting CPAP back around Feb/March (2011)

The fog came back next sleep of course. But i'm very interested in finding out what can lift this fog on a more regular basis.

I seriously doubt the anesthetic had anything to do with this time, as while drugs can lessen my headaches, they tend to make me even more fuzzy.. Seems more likely to me it was the intubation and O2. (I know the only "100% certain" cure for OSA is a tracheotomy, and that last op was the closest I ever want to get to that.)

Has anyone else noticed a similar fog reduction awakening after surgery or receiving extra o2?

I know this indicates something in my treatment needs adjusting, but I'm wondering if supplemental oxygen may help in my case..?

I'll have a proper chat to my GP once i'm mobile and semi-functioning again.

Yeah, you can easily have an overnight pulse ox done which will show if you're desaturating during the night. Lots of people buy their own pulse oximeters and keep track of their O2 on a regular basis.
Do you check your AHI regularly? Are you getting good treatment- sounds like your treatment is not optimal if you're still feeling groggy in the mornings.
Keep us posted on what your GP says. I wish you a speedy recovery.