Just make sure you notify the hospital at every opportunity (at the pre-op, and when talking to the anaesthetist and surgeon on the day).
I've had several ops and procedures in the last few years. If they're worried about a hypo, they'll just give you some glucogen.
As others have said, its more likely that your BG will be high due to stress and any inflammation.
Try to relax as much as you can (I appreciate it's difficult): do whatever you can to take your mind off the op e.g. Read, listen to music, watch tv, meditate (if that's your thing).
All the best
@Saeeda