Incidence, clinical signs, and videofluoroscopic swallow study abnormalities associated with airway penetration and aspiration in 100 dogs

BACKGROUND: Videofluoroscopic swallow studies (VFSS) utilizing penetration‐aspiration (P‐A) scoring assesses airway protection in people. On VFSS, penetration (ingesta or secretions immediately cranial to the vocal folds) and aspiration (material caudal to the vocal folds) are associated with increased risk of lung injury in people. Penetration‐aspiration (P‐A) scoring has been validated in animal models, but the incidence of P‐A, clinical signs (CS), and dysphagic disorders associated with P‐A in dogs are unknown. OBJECTIVES: Using VFSS, identify the incidence of P‐A, compare CS between dogs with and without P‐A, and identify predisposing dysphagic abnormalities for P‐A. ANIMALS: One hundred client‐owned dogs. METHODS: Sequential VFSS and associated medical records from dogs presenting to the veterinary teaching hospitals at Auburn University (n = 53) and the University of Missouri (n = 47) were retrospectively reviewed. Statistical comparisons were made using Mann‐Whitney tests, one‐way analysis of variance (ANOVA) on ranks, multiple linear regression, and Spearman rank order correlation (P < .05). RESULTS: On VFSS, the incidence of pathologic P‐A was 39%. No significant differences in CS were found between dogs with or without P‐A (P > .05), with 14/39 dogs with P‐A presenting without respiratory CS. Pharyngeal (P < .001) and esophageal (P = .009), but not oral‐preparatory (P = .2) dysphagia was more common with P‐A. Pharyngeal weakness (P < .001) and esophago‐oropharyngeal reflux (EOR; P = .05) were independent predictors of P‐A and were moderately and weakly positively correlated with P‐A score respectively (P < .001, r = 0.489; P = .04, r = 0.201). CONCLUSIONS: Penetration‐aspiration occurs in dogs in the absence of respiratory CS (i.e., occult P‐A). Dogs with pharyngeal weakness and EOR should be considered at risk for P‐A.