2017 ACVIM Forum Research Abstract Program

Small breeds and cats with LLT have an excellent prognosis for survival to discharge; the prognosis in large dogs is more guarded. There are limited non-invasive methods available to evaluate lung mechanics. We hypothesized that inspiratory to expiratory change in lung area as assessed by fluoroscopy would result in reproducible measures that could be used for future evaluation of lung function and mechanics in dogs with respiratory disease. Forty-four conscious, unsedated dogs with no evidence of respiratory disease were minimally restrained in sternal recumbency. Tidal respiration was recorded fluoroscopically for 10 respiratory cycles, and maximal inspiratory and expiratory images from 3 respiratory cycles were evaluated. The number of pixels in the entire thoracic cavity was measured for both inspiration and expiration, and the average percent change in thoracic dimension was determined for each dog. This process was repeated using a hemithorax measurement that excluded the mediastinum and cardiac silhouette. Reference ranges with 95% confidence were computed using a non-parametric percentile distribution. Median percent change in thoracic dimension for the total thorax measurement was 12.5% (confidence interval of 8.91-23.97%). Median percent change for the hemithorax measurement (20.8%) was significantly different (P < 0.001) with a larger confidence interval of 14.32-37.61%, rendering it more responsive to lung area changes. Neither measurement technique was correlated with age, sex, thoracic conformation, BCS, or breed but varied with body weight above and below 10 kg. In conclusion, fluoroscopy provides a noninvasive and reliable measure of lung area changes during respiration in small and large dogs. Further investigations of lung area changes are required in dogs with respiratory disease to assess its utility in detecting dysfunction. Environmental tobacco smoke (ETS) exposure in more common in children from lower socioeconomic classes. ETS exposure has been linked with a variety of health risks. Urine cotinine may be used to estimate ETS exposure. The purpose of this study is to evaluate the rate of ETS exposure in dogs and cats from different socioeconomic classes in Massachusetts.