Scientists researched flexible endoscopy in awake dogs to determine if the instrument is effective, safe and tolerated in dogs with swallowing problems. Note the study used large and giant breed dogs.
Source: American Journal of Veterinary Research, March 2016. Page 294-299. (direct link unavailable)
Conclusions and Clinical Relevance: FEES appeared to be a feasible diagnostic tool for use in large- and giant-breed dogs. Studies are warranted in dogs with oropharyngeal dysphagia to determine whether FEES can be tolerated and whether it can augment videofluoroscopy findings. (Am J Vet Res 2016: 77:294-299)