LAUSR

Abstract Background Salivary bile acids are used to diagnose extraesophageal reflux (EER) and to evaluate the risk of reflux aspiration that is associated with respiratory diseases in dogs. Objectives To study total bile acid (TBA) concentrations in saliva and in bronchoalveolar lavage fluid (BALF) to investigate EER and reflux aspiration in dogs with respiratory diseases and in healthy dogs. Animals Thirty‐one West Highland White Terriers (WHWTs) with idiopathic pulmonary fibrosis (IPF), 12 dogs with inflammatory airway disease (IAD), 6 dogs with recurrent pneumonia (RP), 26 brachycephalic dogs (BD), 27 healthy WHWTs (HW), 52 healthy dogs (HD). All privately‐owned dogs. Methods Saliva and BALF were collected from dogs in each group. Results Salivary TBA concentrations were higher in IPF (median 0.1692 μM, interquartile range [IQR] 0.1115‐0.2925 μM, Cohen's d 3.4, 95% confidence interval [CI] 2.2‐4.0, P < .001) and BD (0.0256 μM, IQR 0.0086‐0.0417 μM, d 0.5, CI −0.1 to 1.1, P = .003) compared to HD (0 μM, IQR not quantifiable [n.q.]‐0.0131 μM). Bronchoalveolar lavage fluid TBA concentrations were higher in IPF (0.0117 μM, IQR 0.0048‐0.0361 μM, d 0.5, CI 0‐1.1, P < .001) compared to HD (0 μM, IQR n.q.‐0.0074 μM). Conclusion and Clinical Importance Extraesophageal reflux and reflux aspiration occur in healthy dogs and those with respiratory diseases.