Comparison of dynamic and resting endoscopy of the upper portion of the respiratory tract in 57Thoroughbred yearlings

Abstract

Dynamic overground endoscopic examination could be considered a suitable means of assessing URT function in TB yearlings and may provide additional pertinent information to that obtained during standard resting examination.

Update on Diseases and Treatment of the Pharynx

“…This is supported by reports of increased prevalence of DDSP following URT infections. 13,14 Laryngeal/hyoid position The relative positions of the larynx and hyoid apparatus is another speculated cause of DDSP supported by reports demonstrating a more ventrally located basihyoid bone in horses with DDSP as determined ultrasonographically, and horses with persistent DDSP have a more caudally located larynx than those with less severe, intermittent DDSP. 6,21 Furthermore, increased head and neck flexion increases the incidence of DDSP by a combination of increased negative pressures in the airway and caudal retraction of the larynx.…”

“…This has been demonstrated in several publications where either intermittent DDSP or poor performance was associated with an abnormal appearance of the epiglottis. [14][15][16] However, other authors suggest that the abnormal-appearing epiglottis is a result and not a cause of DDSP. 5 This is further highlighted by the fact that horses with experimentally induced epiglottic retroversion fail to develop DDSP.…”

“…In general, observation of DDSP at rest is a fairly reliable positive predictive test but a very poor negative predictive test for DDSP. 14,26 In all cases the gold standard diagnostic modality is videoendoscopy while exercising, which can be performed using a high-speed treadmill or dynamic over-theground endoscopy. It has been shown that DDSP occurs most commonly during, or at the end of, strenuous exercise.…”

Respiratory Disease

“…[2][3][4][5] Variables such as lack of standardization of the exercise tests, shorter training distances, and an inability to re-create racing conditions have been proposed.…”

Evaluation of poor performance in racehorses using a high-speed treadmill

“…Evaluation of equine athletes often requires additional special diagnostic methods including exercise testing because findings in resting horses may be unremarkable or equivocal. Several studies have documented that, in particular, dynamic upper respiratory tract obstructions cannot be diagnosed accurately during resting endoscopic examination and that endoscopy during exercise is required to make a definitive diagnosis (Lane et al 2006;Allen and Franklin 2010;Garret et al 2011;Kelly et al 2013). Exercise testing can be performed on a high-speed treadmill or in the field using overground endoscopy.…”