I know this is an older thread, but good for everyone.
I know my small animal vet tranqs them lightly, and then masks them with sevo. They have a great monitoring system complete with a warming jacket and warm water bed under the table to prevent temp drops. The great thing about the sevo and even iso I believe is they are awake within seconds of taking off the mask. They recover quicker from the anesthesia.
There are debates about it, but there are debates about everything in the veterinary field I guess
I know the sevo is much easier on them internally, and mine (and most small animal vets around here) won't cut any small dogs or cats any other way.
Great thread Crystal.