Former RN here. If you are having anesthesia, you should not use pot before at least a day or so, before your surgery - especially if you smoke it. Smoking anything in any way is bad before having anesthesia. And, pot can alter your BP and HR, which increases your risks during surgery.

When you get home, follow their discharge instructions, and when you are not using Vocodin (or something like it) you can resume your usual activities.