title: Dynamic respiratory videoendoscopy in ridden sport horses: effect of head flexion, riding and airway inflammation in 129 cases.
abstract: BACKGROUND
  Dynamic upper airway obstruction (UAO) is a cause of respiratory noise and sometimes poor performance in sport horses. Riding, head flexion and airway inflammation may impact upper respiratory tract stability during exercise.
  
  
  OBJECTIVE
  To evaluate upper airway mechanical behaviour in ridden sport horses using overground endoscopy and the effect of head flexion, rider intervention and underlying airway inflammation on the pharynx and larynx.
  
  
  METHODS
  Resting and exercising videoendoscopic recordings during ridden exercise were obtained in 129 sport horses referred mainly for respiratory noise, poor performance or routine evaluation. The rider modified poll flexion and way of riding during the test and associated changes in UAO were recorded. Presence of upper and lower airway inflammation was also assessed.
  
  
  RESULTS
  Dynamic UAO was diagnosed in 91% (64/70) of the horses referred for respiratory noise and in 71% (29/41) of horses referred for poor performance. Pharyngeal instability was the most frequently diagnosed problem. However, differences were observed between dressage horses and showjumpers. Rider interaction and head flexion exacerbated upper airway instability and promoted the occurrence of complex UAO. Both lower airway inflammation and pharyngeal lymphoid hyperplasia were associated with pharyngeal instability, but not with any other UAO.
  
  
  CONCLUSIONS
  Rider intervention during ridden exercise (i.e. the various movements a horse might be asked to perform) influences upper airway morphology and function and, in cases of upper airway dynamic obstruction, can contribute to increasing laryngeal and/or pharyngeal instability in sport horses.
  
  
  CONCLUSIONS
  As these are changes that would not usually be seen with treadmill videoendoscopy, ridden videoendoscopy should be the preferred method for evaluation of the upper airway in sport horses.
authors.affiliation: Equine Sports Medicine Practice, Brussels, Belgium. Emmanuelle.vanerck@skynet.be
authors.forename: E
authors.initials: E
authors.lastname: Van Erck
mesh_terms: D000818:Animals; D004724:Endoscopy / Q000662:veterinary*; D005260:Female; D006734:Horse Diseases / Q000209:etiology / Q000473:pathology*; D006736:Horses; D007249:Inflammation / Q000473:pathology / Q000662:veterinary*; D008297:Male; D012137:Respiratory System / Q000473:pathology*; D012140:Respiratory Tract Diseases / Q000473:pathology / Q000662:veterinary*; D014741:Video Recording / Q000379:methods*