External abdominal pressure radiography versus survey radiography for the diagnosis of hiatal hernia in brachycephalic dogs

Hiatal hernia (HH) is a common disorder in brachycephalic dogs with upper airway obstruction. The breathing effort results in an exaggerated transdiaphragmatic pressure gradient during inspiration that can displace the gastroesophageal junction causing gastroesophageal reflux. The diagnosis is challenging because the HH usually occurs intermittently and is often missed on survey radiography. In this retrospective study, the application of external abdominal pressure to mimic the transdiaphragmatic pressure gradient during radiographic screening for HH was evaluated in 146 dogs. Hiatal hernia was diagnosed with external abdominal pressure radiographs in 6.8% (10/146 dogs), whereas it was diagnosed via survey radiography in only 2% (3 dogs). In conclusion, the radiographic diagnosis of HH in brachycephalic dogs can be improved by performing external abdominal pressure radiographs.