The respiratory & gi tract share overlapping mechanisms required for breathing & swallowing. The prevalence of gi disease in brachycephalic dogs presenting for respiratory signs is as high as 97% (Poncet 2005 l/2006; Kaye 2018; Freiche & German 2021).

The most common signs are regurgitation, vomiting & dysphagia (Roedler 2013; Freiche & German 2021).

Congenital/acquired hiatal hernia (HH), frequently represents an additional finding for BOAS. HH is defined as prolapse of abdominal organs through the oesophageal hiatus into the mediastinum & is exacerbated in brachycephalic dogs by an abnormal intrathoracic & intra-oesophageal pressure (Reeve 2017; Broux 2018)

Herniation of the stomach leads to chronic regurgitation & predisposes to oesophagitis, GDV & aspiration pneumonia (Mayhew et al. 2021).

Oesophageal motility disorders are common in brachycephalic dogs, & include prolonged oesophageal transit time (Reeve et al. 2017), & prolonged secondary peristaltic waves (Eivers et al. 2019). These variations predispose to gastroesophageal reflux disease (Poncet 2005 2006; Reeve et al. 2017; Kaye 2018; Eivers 2019).

GERD is defined as the pathological reflux of gastric or duodenal contents with resultant oesophagitis, oesophageal ulceration, & in some cases oesophageal strictures (Freiche & German 2021).

The pathophysiology is multifactorial. Incompetence of the lower oesophageal sphincter (LES), obesity & increased abdominal pressure are major contributors (Mönkemüller 2012; Kempf 2014).

Signs of GERD include lip smacking, ptyalism, extension of head & neck while swallowing, retching, vomiting, regurgitation, grass ingestion, surface licking, dysphagia, nocturnal restlessness, & anorexia (Poncet et al. 2005, 2006; Reeve et al. 2017; Eivers 2019).

We have an ethical responsibility to prevent & minimise the negative health & welfare impacts of extreme brachycephaly as the affected animals do not enjoy all the 5 freedoms of animal welfare under human control (freedom from hunger & thirst, discomfort, pain, injury & disease, fear & distress, & to express normal behavior