spaying and neutering my kitties-- anesthetic

Well, Bonnie and Clyde, the two adorable kittens we adopted a month and a half ago are now apparently old enough to get fixed (so sayeth the shelter-- even though they are only 12 weeks). We have a voucher to do it at the shelter where we adopted them. I am very worried though about the anesthetic. I have read all kinds of crazy stuff on the internet about how dangerous it is for some kitties. I will just be devestated if anything happens to either of them. Now obviously, we are going to get them fixed-- there is no alternative. I just wondered if anyone could put my mind to ease about the safety of this procedure. Also, these guys were shelter kitties-- do you think they will think we are abandoning them there? They are like our babies and I don't want them to feel afraid at all. Thanks!

It is not possible to test for an 'allergy' to an anesthetic drug. The preoperative testing is to check the liver, kidneys, blood sugar and protein levels, etc. and to rule out anemia and make sure the white blood cell count is normal prior to surgery, to minimize risks. This is important in any age cat, as congenital liver and kidney problems do occur, and can't be detected by physical examination alone.

Normal results do not guarantee that there might not be an anesthetic problem, but greatly reduces the risk. (Assuming they have already been tested for FeLV/FIV and intestinal parasites..which should ALWAYS be done first.) No one can ever *promise* you that they won't have complications, and you don't want anyone to do that anyway..because it seems like that's exactly when complications are going to happen. (Murphy's Law)