[Ponyup]

I don't know if I'm much help, but when I used to work at the vet office. They did put a tube down the throught of a small dog (like 20lbs) for a hernia surgery, but did not for a neuter and when they declawed a cat I had to hold an oxygen mask over it's little face. When my cat got spayed (i stayed and watched) they did not use a tube or oxygen mask and she was fine. The surgery took at most 10 minutes. Logan does a reverse sneezing thing, but only when excited. He had no problem with his neuter. I would imagine yours won't either because they should be asleep therefore relaxed. My understand of reverse sneezing is that it's almost like asmetha (sp?) since your vet knows he has this problems I would imagine they would let you know if there could be any complications.