Impact of pharyngeal endoscopic tip placement and water flushing interval on upper respiratory tract disorders in horses undergoing overground endoscopy.
Authors: McGivney C L, Sweeney J, Gough K F, Hill E W, Katz L M
Journal: Equine veterinary journal
Summary
# Editorial Summary: Endoscopic technique and upper respiratory tract assessment during overground endoscopy Accurate diagnosis of exercise-induced upper respiratory tract (URT) disorders relies heavily on reliable endoscopic methodology, yet the technical variables affecting image quality and diagnostic interpretation during overground endoscopy (OGE) remain poorly characterised. McGivney and colleagues investigated whether two key procedural factors—the rostral versus caudal positioning of the endoscope tip within the pharynx and the interval between automated water flushes (ranging from continuous flushing to no flushing)—influenced the grading of four common URT conditions in 200 horses performing at exercise. The researchers found that endoscope tip position significantly affected palatal dysfunction grading, with 63% of horses diagnosed when the scope was positioned rostrally compared to 45% when positioned caudally; whilst water flushing intervals showed no direct effect on disorder grading, exercise velocity appeared to interact with both positioning and flushing to modulate the severity grading of medial deviation of the aryepiglottic folds. These findings highlight that diagnostic consistency during OGE is vulnerable to subtle variations in technique, particularly for palatal assessment, and that practitioners should standardise their endoscope positioning protocol to improve reproducibility and reduce the risk of misgrading severity, though the authors acknowledge that sample size limitations prevent definitive conclusions about all potential interactions between variables and specific pathologies.
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Practical Takeaways
- •Standardize endoscope tip position (rostral or caudal in pharynx) when performing overground endoscopy to ensure consistent and comparable palatal dysfunction assessment between examinations
- •Water flushing intervals from 60–240 seconds do not meaningfully change diagnostic findings, allowing flexibility in protocol based on clinical preference
- •Account for exercise velocity when interpreting medial aryepiglottic fold findings, as this variable interacts with both endoscope position and flushing protocol to affect grading
Key Findings
- •Endoscope tip position in the pharynx significantly affected palatal dysfunction grading (P=0.002), with 63% diagnosed in rostral position versus 45% in caudal position
- •Water flushing interval (60–240 seconds) was not directly associated with changes in upper respiratory tract disorder grading
- •Exercise velocity interacted with endoscope position and flushing interval to influence medial deviation of the aryepiglottic folds grading
- •Endoscope positioning had no significant direct effect on arytenoid asymmetry or vocal fold collapse severity