Dynamic obstructions of the equine upper respiratory tract. Part 1: observations during high-speed treadmill endoscopy of 600 Thoroughbred racehorses.
Abstract: 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: 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.
Publication Date: 2006-09-22 PubMed ID: 16986598DOI: 10.2746/042516406778400583Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research investigated the occurrence and nature of dynamic airway obstructions in Thoroughbred racehorses, particularly those experiencing poor performance, using treadmill exercise testing and video endoscopic recordings. It found that dynamic collapse of the upper respiratory tract was common and often complex, with palatal instability and dorsal displacement of the soft palate the most frequently identified disorders.
Methodology
- The study reviewed video-endoscopic recordings of the upper respiratory tracts of 600 Thoroughbred racehorses during a standardized treadmill exercise test.
- These recordings were analyzed in real time and slow motion to spot any dynamic collapses by the tissues adjacent to the pharyngeal and laryngeal airways.
Findings
- 471 out of the 600 horses exhibited dynamic collapse within the nasopharynx or larynx.
- The most frequently identified disorders were palatal instability (33%) and dorsal displacement of the soft palate (DDSP; 50%).
- The research concluded that deglutition (swallowing process) doesn’t significantly trigger DDSP.
- 30% of horses with upper respiratory tract obstructions showed complex forms of dynamic collapse where more than one structure collapses into the airway.
- The prevalence of DDSP and dynamic laryngeal collapse was significantly influenced by age. Younger horses were more prone to DDSP, while older horses were more likely to experience laryngeal collapse.
- There was no identified association with the gender or racing format of the horses.
Conclusions
- Palatal instability and DDSP were the most common forms of dynamic collapse within the upper respiratory tract of the Thoroughbred racehorses in the study. These conditions are likely indicating the same nasopharyngeal malfunction.
- Complex obstructions that involve multiple structures collapsing into the airway frequently occur, which means treatments addressing solitary disorders may often be unsuccessful.
- Younger horses were found to be more at risk of DDSP, while older horses were more vulnerable to laryngeal collapse—but not the collapse of the arytenoid cartilage itself.
Cite This Article
APA
Lane JG, Bladon B, Little DR, Naylor JR, Franklin SH.
(2006).
Dynamic obstructions of the equine upper respiratory tract. Part 1: observations during high-speed treadmill endoscopy of 600 Thoroughbred racehorses.
Equine Vet J, 38(5), 393-399.
https://doi.org/10.2746/042516406778400583 Publication
Researcher Affiliations
- Department of Clinical Veterinary Science, University of Bristol, Langford, UK.
MeSH Terms
- Age Factors
- Airway Obstruction / diagnosis
- Airway Obstruction / epidemiology
- Airway Obstruction / etiology
- Airway Obstruction / veterinary
- Animals
- Arytenoid Cartilage / physiopathology
- Endoscopy / methods
- Endoscopy / veterinary
- Exercise Test / veterinary
- Female
- Horse Diseases / diagnosis
- Horse Diseases / epidemiology
- Horse Diseases / etiology
- Horses
- Larynx / abnormalities
- Larynx / physiopathology
- Male
- Nasopharynx / abnormalities
- Nasopharynx / physiopathology
- Palate, Soft / abnormalities
- Palate, Soft / physiopathology
- Physical Conditioning, Animal
- Prevalence
- Respiratory System Abnormalities / diagnosis
- Respiratory System Abnormalities / epidemiology
- Respiratory System Abnormalities / physiopathology
- Respiratory System Abnormalities / veterinary
- Retrospective Studies
- Video Recording
Citations
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