My miniature daschund has been having trouble with choking for about a month now. When she eats she starts shaking and choking on food and a really thick clear mucus. I have had her to 2 vets and neither one gave me an answer. One vet did blood tests and said they came out perfect. So this just started about a month ago. Do you have any ideas what could be causing these attacks?

I would keep working with the vets.

Rothes, I agree with labman. If I were you I would stay on top of the vets backs and I wouldn't let them dismiss my concerns. If you don't feel they are doing the right thing by your dog, then find another vet. You are very right to be as concerned as you are. Your doxie is having a health issue and they must find an answer. Did either vet talk to you about megaesaphogus? Please take a look at this link in which I have responded to another poster about their dog regurgitating water. https://www.askmehelpdesk.com/dogs/why-does-dog-regurgitate-when-drinking-water-145633.html
I think if megaesaphogus hasn't been discussed, you need to bring it up. Do an internet search on it and gather as much information as you can so that you will be able to have a thorough discussion on the subject with the vet. Please let us know how what the outcome is. I do hope this problem is something that isn't serious and easily remedied.