We had tonsils out with our boy and he was put to sleep. The first part when they put them out and wheel them away was fine.
The waking up part is a bit crazy. My little boy was pretty crazy. He was trying to pull his IV out and kicking and screaming for about 10 min until he got fully oriented.
When they wheeled him up to the room, he was pretty ticked off that they wanted him to get into the bed as bedtime is a bit of a battle. That sounded like punishment to him. What we ended up doing was getting a red wagon wheeled to the room and put it next to the bed and he just sat in there with the IV poles next to him.
The only other thing I'd mention is that his potty training regressed and returned after the pain meds were done.
Best wishes.