It would not be allowed in my hospital. Anything that uses resistance heat is not allowed in patient areas (unless of course it is hospital grade equipment), due to the possibility of oxygen leaks. Also use of tobacco products is prohibited there, due to the recent court ruling with the FDA then it would be considered a tobacco product. Also the charging equipment would need to be UL listed, if there isn't a UL tag or stamp then it would not be allowed to be plugged into the hospital power supply (all electrical equipment must be inspected by maintence before being plugged in). That said be sure to talk to your doctor about your vaping at least a day or two before your surgery, as there may be side effects or contraindications for anesthesia (I'm just now learning about anesthesia so I can't tell you for sure). Also if Vaping isn't allowed then the doctor can perscribe you an appropriate nicotine patch. Knowing how much you typically vape and the nicotine content of you juice will give them a better idea (than with smokers) on which patch to perscribe. Do not Vape while you are on the patch. If they tell you that you cannot Vape don't "stealth" vape. Actually knowing some of the side effects of vaping I'd say it isn't a great Idea untill you have good strong bowel sounds, as vaping can lead to diarrhea causing material that is in the process of digestion to loosen and move before peristalsis returns (which is not a good thing). Now there are no studies that I know of to prove or disprove that, but it is a possibility, and until more studies are done I would recommend against it, especially considering the surgery you are about to have.
All that said talk to your surgeon about it, be sure to mention that diarrhea seems to be a known side effect of vaping in some people, and see what he/she has to say about it. I am by no means an expert, or a medical professional.