Department of Clinical Studies, New Bolton Centre, University of Pennsylvania, 382 West Street Road, Kennett Square, Pennsylvania 19348, USA.
Correlations between exercising arterial blood gas values, tracheal wash findings and upper respiratory tract abnormalities in horses presented for poor performance
Article first published online: 10 JUN 2010
© 2006 EVJ Ltd
Equine Veterinary Journal
Special Issue: Proceedings of the 7th International Conference of Equine Exercise Physiology
Volume 38, Issue S36, pages 523–528, August 2006
How to Cite
DURANDO, M. M., MARTIN, B. B., DAVIDSON, E. J. and BIRKS, E. K. (2006), Correlations between exercising arterial blood gas values, tracheal wash findings and upper respiratory tract abnormalities in horses presented for poor performance. Equine Veterinary Journal, 38: 523–528. doi: 10.1111/j.2042-3306.2006.tb05598.x
- Issue published online: 10 JUN 2010
- Article first published online: 10 JUN 2010
- tracheal wash;
- poor performance;
Reasons for performing study: There are limited data on the correlations between arterial blood gas (ABG) values, tracheal wash (TW) cytology and upper respiratory tract (URT) abnormalities.
Objectives: To identify horses with abnormal exercising ABG, and compare the proportions of horses with abnormal ABG and TW cytology, mucus or URT dysfunction with those with normal ABG results and abnormal TW cytology, mucus or URT dysfunction.
Methods: Medical records of 813 horses presenting to the treadmill facility that had a complete treadmill examination, including ABG analysis, TW and URT endoscopy were selected. Diagnoses, ABG results, TW cytology and URT endoscopy were compared.
Results: Two hundred and eleven horses met the study criteria of a complete treadmill examination and could have ABG evaluated. There were no significant differences in the age distribution of horses having normal and abnormal ABG or upper respiratory tract (URT) examinations. There was a significantly higher percentage of geldings with abnormal ABG analysis. In the horses with abnormal URT examinations, there were no differences in the proportion of horses having mucus vs. no mucus. However, in the horses with normal URT, there were a higher percentage of horses with visible mucus in the group with abnormal ABG analysis. The majority of horses had abnormal TW cytology and evidence of prior EIPH, with no differences in proportions between the groups.
Conclusions: Because such a large percentage of horses had evidence of inflammation and/or evidence of prior EIPH on TW cytology, it was not possible to determine the effect of these findings on gas exchange. Mucus was present in a larger percentage of cases with abnormal ABG analysis and normal URT examinations, suggesting that the presence of mucus may affect gas exchange. Standardbreds may be more likely to have abnormal gas exchange than Thoroughbreds. A larger number of horses is needed to determine the significance of these findings.
Potential relevance: Abnormal TW cytology and endoscopic visualised mucus may contribute to impairment of gas exchange, but they do not specifically predict abnormal ABG analysis.