Hi fellow Bee-L list subscribers:
I suppose that I wont do any harm this time by posting and answer to Tom's
question to the list since it might be of general information to those who are
not acquanted with medical or veterinary practice.
CO2 does have anesthetic properties. The effect depends on concentration and
conditions for administration.  I seriously doubt that one could use CO2
regualarly in the handling of bees, especially Africanized bees in the open.
However, it could have positive applications though limited if what one wants
is to "tame" down aggressive bees in a confined environment.
Although I hardly use anything when working my bees, personally I prefer good
old smoke.
Best regards.
Dr. Rodriguez