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Equine veterinary journal2006; 38(5); 401-407; doi: 10.2746/042516406778400619

Dynamic obstructions of the equine upper respiratory tract. Part 2: comparison of endoscopic findings at rest and during high-speed treadmill exercise of 600 Thoroughbred racehorses.

Abstract: The reliability of diagnoses of obstructive conditions of the upper respiratory tract (URT) based on examinations performed at rest vs. at exercise is controversial. Objective: To compare diagnosis of URT by endoscopy at rest with that achieved during high-speed treadmill exercise (HSTE). Objective: Endoscopy of URT at rest, when performed in isolation from other simpler techniques is unreliable in the prediction of dynamic respiratory obstructions. Methods: Endoscopic findings of 600 Thoroughbred racehorses during quiet breathing were compared with findings during high-speed treadmill exercise. Other parameters were also assessed for their specificity in diagnosis. Results: Endoscopy of the resting horse showed low sensitivity (0.15) in the diagnosis of dorsal displacement of the soft palate (DDSP) and palatal instability (PI). When endoscopy and reported noises were taken together there was still a 35% misdiagnosis rate. Although there was significant association between resting laryngeal function score (LFS) and dynamic vocal cord and/or arytenoid cartilage collapse at exercise, 19% of horses with a grade 4/5 LFS were able to attain and maintain full abduction during exercise and 7% of those with 'normal' grades 1 or 2 LFS at rest showed dynamic laryngeal collapse when exerted. Sensitivity of the diagnostic model was greatly increased (80%) when a history of inspiratory noise and palpable intrinsic muscle atrophy were included. Conclusions: Endoscopy of the upper respiratory tract of static horses is unreliable in the diagnosis of dynamic obstructions of the URT and should not be used in isolation in surgical decision-making or in the assessment of horses at the time of sale.
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Publication Date: 2006-09-22 PubMed ID: 16986599DOI: 10.2746/042516406778400619Google Scholar: Lookup
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  • Comparative Study
  • Journal Article
  • Research Support
  • Non-U.S. Gov't

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research study investigates the validity of endoscopic evaluation of the upper respiratory tract (URT) in horses while at rest, as compared to during high-speed treadmill exercise (HSTE). The study finds that resting endoscopy alone may not be reliable for diagnosing dynamic obstructions of the URT in horses, and suggests inclusion of other diagnostic factors for accurate assessment.

Research Methodology

  • The study conducted endoscopic examination of 600 Thoroughbred racehorses while they were at rest and compared these findings with results obtained during high-speed treadmill exercise.
  • The horses’ breathing patterns were examined under two distinct conditions to ascertain if resting endoscopy could accurately predict dynamic respiratory obstructions.
  • The study also evaluated other parameters including reported noises, laryngeal function score (LFS) at rest, and the horses’ ability to maintain normal laryngeal function during exercise.

Key Findings

  • Resting endoscopy showed low sensitivity in diagnosing conditions such as dorsal displacement of the soft palate (DDSP) and palatal instability (PI), with a sensitivity score of just 0.15.
  • When results of the resting endoscopy were combined with reported noises, there was still a 35% misdiagnosis rate.
  • The diagnostic model’s sensitivity significantly increased (80%) when a history of inspiratory noise and evidence of palpable intrinsic muscle atrophy were included.

Conclusion

  • The research concludes that endoscopy of horses while at rest is an unreliable method for diagnosing dynamic obstructions of the URT.
  • The study warns against the use of resting endoscopy as a sole diagnostic tool to inform surgical decisions or evaluate horses for sale.
  • It suggests the inclusion of factors such as a history of inspiratory noise and palpable intrinsic muscle atrophy to improve diagnostic accuracy.

Cite This Article

APA
Lane JG, Bladon B, Little DR, Naylor JR, Franklin SH. (2006). Dynamic obstructions of the equine upper respiratory tract. Part 2: comparison of endoscopic findings at rest and during high-speed treadmill exercise of 600 Thoroughbred racehorses. Equine Vet J, 38(5), 401-407. https://doi.org/10.2746/042516406778400619

Publication

Equine veterinary journal
ISSN: 0425-1644
NlmUniqueID: 0173320
Country: United States
Language: English
Volume: 38
Issue: 5
Pages: 401-407

Researcher Affiliations

Lane, J G
  • Department of Clinical Veterinary Science, University of Bristol, Langford, UK.
Bladon, B
    Little, D R M
      Naylor, J R J
        Franklin, S H

          MeSH Terms

          • Age Factors
          • Airway Obstruction / diagnosis
          • Airway Obstruction / etiology
          • Airway Obstruction / veterinary
          • Animals
          • Arytenoid Cartilage / physiopathology
          • Diagnosis, Differential
          • Endoscopy / methods
          • Endoscopy / veterinary
          • Exercise Test / veterinary
          • Female
          • Horse Diseases / diagnosis
          • Horse Diseases / etiology
          • Horses
          • Larynx / abnormalities
          • Larynx / physiopathology
          • Male
          • Nasopharynx / abnormalities
          • Nasopharynx / physiopathology
          • Palate, Soft / abnormalities
          • Palate, Soft / physiopathology
          • Physical Conditioning, Animal / physiology
          • Respiratory Sounds / diagnosis
          • Respiratory Sounds / physiopathology
          • Respiratory Sounds / veterinary
          • Respiratory System Abnormalities / diagnosis
          • Respiratory System Abnormalities / physiopathology
          • Respiratory System Abnormalities / veterinary
          • Rest / physiology
          • Retrospective Studies
          • Sensitivity and Specificity
          • Severity of Illness Index
          • Video Recording

          Citations

          This article has been cited 9 times.
          1. McGivney CL, McGivney BA, Farries G, Gough KF, Han H, Holtby AR, MacHugh DE, Katz LM, Hill EW. A genome-wide association study for recurrent laryngeal neuropathy in the Thoroughbred horse identifies a candidate gene that regulates myelin structure. Equine Vet J 2025 Jul;57(4):943-952.
            doi: 10.1111/evj.14461pubmed: 39791379google scholar: lookup
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            doi: 10.1002/vms3.70018pubmed: 39285763google scholar: lookup
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            doi: 10.3390/ani12121563pubmed: 35739899google scholar: lookup
          4. Ahern BJ, Sole A, de Klerk K, Hogg LR, Vallance SA, Bertin FR, Franklin SH. Evaluation of postsale endoscopy as a predictor of future racing performance in an Australian thoroughbred yearling population. Aust Vet J 2022 Jun;100(6):254-260.
            doi: 10.1111/avj.13155pubmed: 35191021google scholar: lookup
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            doi: 10.3389/fphys.2019.01333pubmed: 31736771google scholar: lookup
          6. Butler D, Valenchon M, Annan R, Whay HR, Mullan S. Living the 'Best Life' or 'One Size Fits All'-Stakeholder Perceptions of Racehorse Welfare. Animals (Basel) 2019 Mar 31;9(4).
            doi: 10.3390/ani9040134pubmed: 30935137google scholar: lookup
          7. Cercone M, Hokanson CM, Olsen E, Ducharme NG, Mitchell LM, Piercy RJ, Cheetham J. Asymmetric recurrent laryngeal nerve conduction velocities and dorsal cricoarytenoid muscle electromyographic characteristics in clinically normal horses. Sci Rep 2019 Feb 25;9(1):2713.
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          8. Jean D, Picandet V, Céleste C, Macieira S, Cesarini C, Morisset S, Rossier Y, Marcoux M. Palatal sclerotherapy for the treatment of intermittent dorsal displacement of the soft palate in 51 standardbred racehorses. Can Vet J 2011 Nov;52(11):1203-8.
            pubmed: 22547840
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            doi: 10.1186/2046-0481-62-5-334pubmed: 21851734google scholar: lookup
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