I don't know what to say except that I have never heard of a viewing pulse from the jugular vein Oh dear.

Did the vet tap her chest for any fluid?? How old is he/she? They will spin down the fluids in a centrifuge in the lab and record the results. You should hear from them ASAP

Believe it or not 400 bucks for an ultrasound and dianostics is very very cheap. Owners spead over a grand for procedures at the local hospital here.

Oh dear.