BedeniceD, Bar-YishayE, IngenitoEP, et al. Evaluation of headout constant volume body plethysmography for measurement of specific airway resistance in conscious, sedated sheep. Am J Vet Res2004;65:1259–1264.
BedeniceDBar-YishayEIngenitoEP, et al. Evaluation of headout constant volume body plethysmography for measurement of specific airway resistance in conscious, sedated sheep. Am J Vet Res2004;65:1259–1264.)| false
Objective—To evaluate the effects of obesity on pulmonary function in healthy adult dogs.
Animals—36 Retrievers without cardiopulmonary disease.
Procedures—Dogs were assigned to 1 of 3 groups on the basis of body condition score (1 through 9): nonobese (score, 4.5 to 5.5), moderately obese (score, 6.0 to 6.5), and markedly obese (score, 7.0 to 9.0). Pulmonary function tests performed in conscious dogs included spirometry and measurement of inspiratory and expiratory airway resistance (Raw) and specific Raw (sRaw) during normal breathing and during hyperpnea via head-out whole-body plethysmography. Functional residual capacity (FRC; measured by use of helium dilution), diffusion capacity of lungs for carbon monoxide (DLCO), and arterial blood gas variables (PaO2, PaCO2, and alveolar-arterial gradient) were assessed.
Results—During normal breathing, body condition score did not influence airway function, DLCO, or arterial blood gas variables. During hyperpnea, expiratory sRaw was significantly greater in markedly obese dogs than nonobese dogs and Raw was significantly greater in markedly obese dogs, compared with nonobese and moderately obese dogs. Although not significantly different, markedly obese dogs had a somewhat lower FRC, compared with other dogs.
Conclusions and Clinical Relevance—In dogs, obesity appeared to cause airflow limitation during the expiratory phase of breathing, but this was only evident during hyperpnea. This suggests that flow limitation is dynamic and likely occurs in the distal (rather than proximal) portions of the airways. Further studies are warranted to localize the flow-limited segment and understand whether obesity is linked to exercise intolerance via airway dys-function in dogs.
Dr. Bach's present address is Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706.
Dr. Chan's present address is Department of Veterinary Clinical Sciences, The Royal Veterinary College, University of London, North Mymms, Hertfordshire, AL9 7TA, England.
Dr. Lofgren was a fourth-year veterinary student at the time of the study.
Supported by Nestlé Purina PetCare, St Louis, Mo.
Presented in part at the 22nd Annual Symposium of the Veterinary Comparative Respiratory Society, Montreal, 2004.