Introduction

Brachycephalic obstructive airway syndrome (BOAS) develops in a proportion of short-muzzled dogs, who suffer respiratory problems as a result of skull malformation. Current diagnostic methods for BOAS are subjective due to the wide range in type and severity of its clinical signs. Unrestrained whole-body barometric plethysmography (WBBP) is a method for quantitative measurement of ventilation, providing objective parameters to assess respiratory function.

Objectives

Here we investigate the ability of WBBP measurements to distinguish, in French bulldogs, absence/minimal BOAS from moderate/severe BOAS.

Methods

Forty-two French bulldogs and twenty non-brachycephalic controls underwent a 30–minute WBBP test while unsedated and at rest. A clinical grading system for BOAS was used to grade each dog. Statistical analyses including quadratic discriminant analysis (QDA) were used to derive the best classifier for use of WBBP as a clinical test.

Results

Whole-body barometric plethysmography flow waveform characteristics were significantly different between non-brachycephalic controls, absence/minimal BOAS French bulldogs, and moderate/severe BOAS French bulldogs. Compared to non-brachycephalic controls, French bulldogs display a significantly lower expiratory time/inspiratory time (Te/Ti) and higher peak expiratory flow rate/peak inspiratory flow rate (PEF/PIF). Means and variance of PEF/PIF and minute ventilation/body weight (MV/BW) were shown to be sensitive indicators of moderate/severe BOAS. Quadratic discriminant analysis clearly discriminates absent/minimal BOAS from moderate/severe BOAS, with the sensitivity, specificity, and classification accuracy at 95.45%, 100%, and 97.62%, respectively.

Conclusion

The application of advanced computational techniques to WBBP carries significant promise as a clinical diagnostic tool for objective BOAS diagnosis, treatment planning, patient follow-up, and breeding selection.