Airway testing linked to lung inflammation in cats

Abstract

OBJECTIVES: To retrospectively assess the relationship between bronchoalveolar lavage fluid analysis and lung function parameters as assessed by means of barometric whole body plethysmography and airway responsiveness testing in cats with chronic bronchial disease and to evaluate the potential application of barometric whole body plethysmography and airway responsiveness testing to distinguish between eosinophilic and non-eosinophilic bronchitis. METHODS: Twelve cats presented for chronic bronchial disease with complete bronchoalveolar lavage fluid and barometric whole body plethysmography data were identified. Cats were retrospectively assigned to eosinophilic bronchitis or non-eosinophilic bronchitis groups on the basis of bronchoalveolar lavage fluid eosinophil percentage (threshold 17%). Airway responsiveness was quantified by calculating the concentration of carbachol-inducing bronchoconstriction (C-Penh-300), defined as a 300% increase of basal enhanced pause (Penh). RESULTS: Log Penh was significantly higher and C-Penh-300 significantly lower in eosinophilic bronchitis cats compared to non-eosinophilic bronchitis cats (P=0·031 and P=0·032, respectively). Bronchoalveolar lavage fluid eosinophil percentage was moderately correlated with log Penh (P=0·012, r=0·70) and showed a weak inverse correlation with C-Penh-300 (P=0·047, r=-0·58). CLINICAL SIGNIFICANCE: This study provides supportive evidence of a correlation between airway eosinophilic inflammation and plethysmographic measures of bronchoconstriction and airway responsiveness. Further investigation of the use of barometric whole body plethysmography to differentiate between forms of chronic bronchial disease in cats is indicated.