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Equine veterinary journal2019; 52(3); 428-434; doi: 10.1111/evj.13189

Radiographic tracheal lumen to vertebral ratios in the normal American Miniature Horse.

Abstract: Tracheal collapse in horses is reportedly uncommon; however, American Miniature Horses are more commonly affected. There is no description of the tracheal luminal diameter of American Miniature Horses, making early detection of tracheal luminal narrowing difficult. Objective: To 1) describe radiographic tracheal luminal diameter in clinically normal American Miniature Horses, 2) report the prevalence of subclinical tracheal collapse in a population of American Miniature Horses, and 3) use tracheal videofluoroscopy to quantify variation in tracheal luminal diameter throughout the respiratory cycle in horses with no clinical respiratory disease. Methods: Descriptive observational reference interval study. Methods: Thirty-four American Miniature Horses with no reported history of respiratory illness were recruited. Lateral cervical and thoracic radiographs were obtained in unsedated standing horses. Dynamic fluoroscopic images were obtained of the cervical and thoracic trachea throughout the respiratory cycle. Horses were then sedated as needed and tracheoscopy was performed. Twenty-nine horses were categorised as normal, and five horses were categorised as subclinically affected based on 25% or greater tracheal narrowing using tracheoscopy for visual assessment. Radiographic tracheal lumen to vertebral body measurements were obtained throughout the cervical and thoracic trachea. Maximum and minimum fluoroscopic tracheal diameter at each site throughout the respiratory cycle was recorded. Results: A mean, median, 95% confidence interval and bootstrapped 95% reference interval of radiographic tracheal diameter to vertebral body ratios were generated in normal horses. The prevalence of subclinical tracheal collapse in this population of American Miniature Horses is 14.7%. Conclusions: Bootstrapped reference range was generated from 29 horses. Conclusions: Radiographic tracheal measurements and ratios of the tracheal diameter to vertebral body in the normal American Miniature Horse are described herein and can be used as a guideline when screening for tracheal disease in American Miniature Horses. The prevalence of subclinical tracheal collapse in American Miniature Horses may be higher than previously reported.
Publication Date: 2019-11-08 PubMed ID: 31596505DOI: 10.1111/evj.13189Google Scholar: Lookup
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  • Journal Article

Summary

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This research examines the tracheal luminal diameter in American Miniature Horses and its implications in diagnosing tracheal diseases. The study also estimated the occurrence of subclinical tracheal collapse in this horse breed.

Research Objectives

The purpose of this study was three-fold:

  • To describe the tracheal luminal diameter in clinically healthy American Miniature Horses.
  • To determine the prevalence of unnoticed tracheal collapse in American Miniature Horses.
  • To measure the variation in tracheal luminal diameter through the horses’ respiratory cycle using tracheal videofluoroscopy.

Methodology

The research was a descriptive observational reference interval study involving 34 American Miniature Horses with no history of respiratory illness. The horses underwent lateral cervical and thoracic radiographs without sedation, dynamic fluoroscopic images of the cervical and thoracic trachea through their respiratory cycle, and tracheoscopy with sedation as necessary.

The tracheoscopies categorised the horses into two groups: normal (29 horses) and subclinically affected (5 horses). The subclinical categorisation was based on tracheal narrowing greater than 25%.

Measurements included radiographic tracheal lumen to vertebral body ratios from the cervical and thoracic trachea, as well as maximum and minimum fluoroscopic tracheal diameters at each site throughout the respiratory cycle.

Findings

The study generated statistical data (mean, median, 95% confidence interval, and bootstrapped 95% reference interval) about tracheal diameter to vertebral body ratios in healthy horses. The prevalence of subclinical tracheal collapse in this population was found to be around 14.7%.

This study’s findings offer detailed tracheal measurements and ratios of the tracheal diameter to vertebral body in healthy American Miniature Horses. Additionally, the research suggests that the prevalence of subclinical tracheal collapse in American Miniature Horses might be higher than the previous understanding.

In conclusion, these radiographic measurements and ratios are extremely valuable and can provide a guideline for early screening of tracheal diseases in American Miniature Horses.

Cite This Article

APA
Every LJ, Hostnik ET, Hostnik LD, Yardley J, Shore-Khirallah AT, Thompson A, Linn SC. (2019). Radiographic tracheal lumen to vertebral ratios in the normal American Miniature Horse. Equine Vet J, 52(3), 428-434. https://doi.org/10.1111/evj.13189

Publication

ISSN: 2042-3306
NlmUniqueID: 0173320
Country: United States
Language: English
Volume: 52
Issue: 3
Pages: 428-434

Researcher Affiliations

Every, L J
  • Department of Veterinary Clinical Sciences, The Ohio State University, Columbus, Ohio, USA.
Hostnik, E T
  • Department of Veterinary Clinical Sciences, The Ohio State University, Columbus, Ohio, USA.
Hostnik, L D
  • Department of Veterinary Clinical Sciences, The Ohio State University, Columbus, Ohio, USA.
Yardley, J
  • Department of Veterinary Clinical Sciences, The Ohio State University, Columbus, Ohio, USA.
Shore-Khirallah, A T
  • Department of Veterinary Clinical Sciences, The Ohio State University, Columbus, Ohio, USA.
  • Fallon Animal Clinic, Lunenburg, Massachusetts, USA.
Thompson, A
  • Department of Veterinary Clinical Sciences, The Ohio State University, Columbus, Ohio, USA.
  • Lake Equine Associates, Northfield, Ohio, USA.
Linn, S C
  • Department of Veterinary Clinical Sciences, The Ohio State University, Columbus, Ohio, USA.

MeSH Terms

  • Animals
  • Horse Diseases / diagnostic imaging
  • Horses
  • Neck
  • Radiography
  • Spine
  • Trachea
  • Tracheal Diseases / veterinary
  • United States

Grant Funding

  • Ohio State University Equine Research
  • Ohio State Racing Commission

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Citations

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