Impact of pharyngeal endoscopic tip placement and water flushing interval on upper respiratory tract disorders in horses undergoing overground endoscopy.

The study explores the correlation between the positioning of an endoscopic tip in the horse’s pharynx and the frequency of water flushing with the results of an overground endoscopic examination. Four key upper respiratory tract disorders in horses were considered. The findings suggest the endoscope’s position does influence the grading of palatal dysfunction but doesn’t seem to impact other conditions directly. Flushing interval did not show a direct effect on disorder grading.

Research Design and Methodology

• The research employed a randomized balanced 2X5 factorial design. A total of 200 horses undergoing Overground Endoscopy (OGE) were enlisted for the study.
• The horses were divided into 10 groups with each having 20 members. Each group was assigned a different automated endoscopic Flushing Interval (FI) – no flushing, 60 seconds, 120 seconds, 180 seconds, and 240 seconds.
• The endoscope tip was positioned either rostrally (position A) or caudally (position B) in the horse’s pharynx.
• The endoscopic videos were analyzed and all upper respiratory tract abnormalities were recorded and graded using published scales.

Results of the Research

• The position of the endoscope tip within the pharynx was found to have a significant impact on palatal dysfunction (PD) grading. Specifically, 63 out of 100 horses diagnosed with PD were in position A while 45 out of 100 were in position B.
• However, no major direct associations were found between the other upper respiratory tract diseases and the position of the endoscope tip. Still, interactions between exercise velocity and endoscope position did seem to have an effect on medial deviation of the aryepiglottic folds (MDAF) grade.
• The frequency of water flushing was not directly associated with alterations in disorder grading. However, interactions between exercise velocity and FI seemed to have an impact on MDAF grade.

Conclusions of the Research

• The research concluded that the position of the endoscope within the pharynx does appear to influence the grading of PD during OGE examinations.
• Exercise velocity may also affect the grading of MDAF through interactions both with the endoscope’s position and the flushing interval.
• The study acknowledged its limitations, including potential sample bias as not all test conditions were evaluated on the same horse. Also, the sample size was not big enough to conclusively explore the relationship between all factors and disorder grading.