Characterization of Brachycephalic Obstructive Airway Syndrome in Cats Using Barometric Whole-Body Plethysmography

Abstract

Brachycephalic cat breeds refer to cats with a short-nosed or flat-faced conformation, which can be associated with variable severity of upper airway obstruction (UAO) known as brachycephalic obstructive airway syndrome (BOAS). These structural abnormalities may restrict airflow through the upper airway and reduce effective ventilation. This study evaluated whether barometric whole-body plethysmography (BWBP), a non-invasive test that records breathing signals while a cat rests in a chamber after an adaptation period in a quiet environment, can be used clinically to identify and grade UAO severity in brachycephalic cats. Forty-three client-owned cats were enrolled, classified as having highgrade UAO (clinically evident effects on clinical signs or physical examination findings) or low-grade UAO (no clinically evident problems), and compared with healthy nonbrachycephalic control cats. Both brachycephalic groups had lower minute ventilation than non-brachycephalic controls, suggesting impaired ventilation. Cats with high-grade UAO also showed additional evidence of limited inspiratory flow and increased upper airway resistance. These results suggest that brachycephalic conformation in cats is associated with functional impairment of ventilation. This study demonstrates that brachycephalic conformation has physiological impacts and should be recognized as a welfare concern in cats. Additionally, BWBP’s ability to detect these changes highlights its value as a diagnostic and grading tool for assessing UAO in cats.