I had to go to the hospital the other day but didn't vape. I guess I need to test my boundaries, but this particular hospital is very anti-smoking. You have to be at least 1500 ft. away from the hospital even to smoke. Maybe one day. 
And it frightens me that our health can be entrusted with these ....... It's one thing to BE ignorant, but to willfully stay that way makes you pretty worthless.
Wife in hospital for a week. Most nurses and doctors were curious about it but didn't say not to use it and were surprised when I told them I quit within 1 week of starting with e-cigs and haven't smoked for over 2 years. Even the respiratory therapist didn't have a problem with it. I think that some of the alebuterol (sp)treatments may have PG in them. I know that intravenous drugs use PG. One nurse came in and said "Oh baby it smells good in here! Smells like chocolate!" lol
I was at the hospital visiting my mom when a nurse came in to check on her and "caught me" vaping. She was all like, "you can't smoke in here, sir." I attempted to explain that I wouldn't dare smoke in the hospital and that it was a harmless vapor that she was seeing me exhale. Then she said "Well, that's not allowed in here." So naturally I said, "why not?" and she said something to the effect of: because we wouldn't want it messing with the o2 machines. So I pretty much threw in the towel with that conversation and continued to pass the PV back and forth with mom, stealthy at that point.[/QUOTE
When you get this argument, it's time to pull out the real facts for the nurses and tell them it's the exact same stuff they pump in through the HVAC system to purify the air in the hospital... That should silence any nay-sayers.
Another tip I picked up for stealth vaping is to hold my breathe for a few seconds after the inhale, as almost no vapor comes out on the exhale.