Hello, and thank you very much for the replies. I set nodigests, so
yesterday I was able to review them and then talk things over with the
tech/anesthesiologist (the procedures were scheduled for shortly after
8:30 am this morning). Briefly put, the conversation revealed that they
were more flexible than I thought, and didn't have a problem with a
lesser fast. The main concern seemed to be a large, one-sitting intake
after midnight... particularly if it were close to the T-4/T-6 hr
range. What actually transpired was he ate a good meal some hours
before T-12, ate a 6-kibble snack around T-9, ate a 5-kibble snack
at T-6.5, then had nothing after that. The final hour or so he was
irritable, but otherwise the schedule seemed to satisfy him. The
lump was removed and declared a benign tumor not worth testing.
Unfortunately, after numerous attempts at different sites all they had
was maybe 1/3rd of the blood volume they wanted, but they said they
would ping the lab and try to make the most of it. My guy is home and
quietly recovering in a single level cage. He's sleepy but alert/bright
at times... not at all adverse to food or water but I'm pacing him...
shakes/favors his foot due to the removal and staples... otherwise
fine.

This was a somewhat frustrating experience in that I didn't expect
to encounter 6-8 hr differences in recommended fasting times for a
generally healthy ferret. When you add to that the fact that "no food
or water after X" could translate into no food or water for X plus 4,
6, or more hours depending on when the ferret last visited the bowls,
and then in some cases even more hours depending on when the procedure
is actually done, you could end up with some ferrets hitting the mask
4-6 hours after last consumption and others hitting the mask lets say
12-17 hours after last consumption. To an untrained very cautious
parent such as myself, that kind of delta seems large in the absence
of something requiring special attention.

A few comments meant to address some things in the replies...

The blood test just seemed like a good idea given his age and some
recently frequent, larger, dilute pees. The vet suggested the urine
concentration test, I threw out the idea of also doing some blood
work. WRT to the limited blood for testing, they said they would give
priority to kidney function tests.

Grapedfert is simply short for graped ferret as in one with grape tail.
I love the smell of grape tail in the morning :-) My guy has probably
had a half dozen grapes during his lifetime and given that I don't buy
them for myself any more he probably won't have another. He has never
had an interest in raisins <shrug>.

If there is some consensus amongst the most experienced and active
ferret vets regarding fasting protocols, and if some number of them
coauthored/cosigned a publically available paper, said would be a
valuable educational tool.

[Moderator's note: Setting onself to "nodigests" is not usually an
option on the FML -- the request is normally ignored by the server.
It takes some time for the server to sync everything up in the case
of new subscriptions and in this case "nodigests" evidently held for
a few hours -- perhaps for the good. BIG]

[Posted in FML 5652]