I dont think the meal itself killed her by itself. Stress from regurge could of contributed but i think the culprit is the resp. The fact your vet isnt a herp vet leads me to think they didnt first do a culture before treatment of the resp. What kind of antibiotics did you give her? Injections? If injections whete were you injecting? Resp can get in deep in the lungs and if its not caught soon into it the infection can be irreversible.