Dynamic obstructions of the equine upper respiratory tract. Part 1: observations during high-speed treadmill endoscopy of 600 Thoroughbred racehorses

dc.contributor.authorLane, J.
dc.contributor.authorBladon, B.
dc.contributor.authorLittle, D.
dc.contributor.authorNaylor, J.
dc.contributor.authorFranklin, S.
dc.date.issued2006
dc.description.abstractReasons for performing study and objective: To review the prevalence of single and complex forms of dynamic airway obstructions within a large group of Thoroughbred horses in training referred for investigation of poor performance. Methods: Video-endoscopic recordings of the upper respiratory tract made during a standardised treadmill exercise test of 600 Thoroughbred racehorses were reviewed and analysed in real time and slow motion to identify dynamic collapse by the tissues bordering onto the pharyngeal and laryngeal airways. Results: Dynamic collapse within the nasopharynx or larynx was confirmed in 471 of the 600 horses. Dorsal displacement of the soft palate (DDSP; 50%) and palatal instability (33%) were the disorders most frequently identified. It was concluded that deglutition is not a significant event in the triggering of DDSP. Complex forms of dynamic collapse were present in 30% of the horses with upper respiratory tract obstructions. A significant influence of age on the prevalence of DDSP and dynamic laryngeal collapse was identified. There was an increased risk of DDSP in younger horses, and of laryngeal collapse in older horses. No association with gender or format of racing was identified. Conclusions and potential relevance: Palatal instability and DDSP comprised the most frequently encountered forms of dynamic collapse within the upper respiratory tract of the Thoroughbred racehorses in this study and are probably expressions of the same nasopharyngeal malfunction. Complex obstructions, i.e. where more than one structure collapses into the airway, occur frequently and therefore treatments that address solitary disorders may often be unsuccessful. Younger horses were found to be at greater risk of sustaining DDSP while older horses seemed more at risk to vocal cord collapse but not to collapse of the arytenoid cartilage itself.
dc.description.statementofresponsibilityJ. G. Lane, B. Bladon, D. R. M. Little, J. R. J. Naylor and S. H. Franklin
dc.identifier.citationEquine Veterinary Journal, 2006; 38(5):393-399
dc.identifier.doi10.2746/042516406778400583
dc.identifier.issn0425-1644
dc.identifier.issn0425-1644
dc.identifier.orcidFranklin, S. [0000-0002-6761-5371]
dc.identifier.urihttp://hdl.handle.net/2440/68639
dc.language.isoen
dc.publisherEquine Veterinary Journal Ltd
dc.rightsCopyright status unknown
dc.source.urihttps://doi.org/10.2746/042516406778400583
dc.subjecthorse
dc.subjectracing
dc.subjectdynamic airway obstruction
dc.subjecttreadmill
dc.subjectendoscopy
dc.titleDynamic obstructions of the equine upper respiratory tract. Part 1: observations during high-speed treadmill endoscopy of 600 Thoroughbred racehorses
dc.typeJournal article
pubs.publication-statusPublished

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