Every vet will have its own procedure but I have always found the areas where cats are cared for, very warm indeed............and i feel the cold!
I would not imagine and have not seen heat pads or the such, usually stainless steel cages, with a litter tray and food, if allowed to eat, blanket.
Everything should be very clean and every animal has its own notes and some will be waiting for ops, some will be post ops, some nearly ready to go home.
If its a big vets then cats and dogs maybe in different areas.
Pre op no eating for the patient for a number of hours, depending on age put on IV fluids.