I'm sure that you are past the "is it necessary" point, so I'll skip that. And I have never had to face surgery with PD so I can't comment directly. I will, however, tell you what I would do in these circumstances.

First I would search this forum for "anesthetics". That should turn up an article I posted a couple of years ago about the different options for PWP by a world class anesthesiologist. Make sure everyone has a copy well in advance.

Second, I would be sure that everyone on all shifts knew just how essential it was that my med schedule be followed and that fiteen minutes delay can be more than inconvenient. Also, I'd get my doc to note on my chart that I was in charge of my meds and could take extras if needed. And I'd have an advocate on hand to enforce it.

Third, as you suspect, the stress is the big thing. Both physical and emotional. I would get my doctor to prescribe anti-anxiety medication but under my control. If I didn't want it then that should be my decision.

Finally, and I am speaking from experience here, I would find myself a psychologist who was also a hypnotherapist and I would work with him or her so much that I would be the coolest and most relaxed patient ever. Don't underestimate the good that this could do. The last time I had an MRI I dreaded it because of my claustrophobia. I know a bit about hypnosis and made myself a tape assuring me not only that I would chill through the whole thing but that my time sense would be altered so that it would seem to be no more than five minutes. The thirty or so minutes flew by and really did seem to be five.

-rick