Inspiratory muscle training for the treatment of dynamic upper airway collapse in racehorses: A preliminary investigation.

This research is focused on exploring the use of inspiratory muscle training (IMT) as a non-surgical intervention for treating upper airway collapse (UAC) in racehorses during exercise. The initial results indicate that IMT might improve the stability of the upper airway, however, more research is required due to the small sample size of this preliminary investigation.

Objective of the Study

• The study aimed to evaluate the feasibility of introducing IMT for racehorses, a treatment usually employed for human athletes with exercise-induced laryngeal obstruction.
• The research also sought to document and analyze the exercising endoscopy findings before and after the application of IMT in racehorses diagnosed with dynamic UAC.

Methodology

• Horses participating in the study were subjected to IMT, while wearing a mask with a connected threshold-valve. This valve imposed a load during inhalation, promoting an exercise stimulus intended to strengthen the upper airway muscles.
• The training routine involved a session each day, five to six days a week over a ten-week span.
• The endoscopy recordings obtained pre and post IMT were evaluated using an established grading system as well as a subjective pairwise analysis. The results were compiled keeping the evaluators uninformed to avoid bias.

Findings

• Out of 17 horses that finished the IMT protocol, complete details were accessible for 10 horses.
• Analysis of these 10 entries showed improvements in multiple parameters, such as vocal fold collapse, palatal instability, and intermittent dorsal displacement of the soft palate in several horses post-IMT.
• Comparative subjective analysis also suggested better overall airway function in some horses, post-IMT.

Limitations and Future Research

• The study is preliminary, with the main limitation being the small number of horses that could be examined and the lack of a control population.
• Further research is essential to assess the ultimate impact of IMT on the strength of upper airway muscles in horses and to validate its efficacy in preventing and treating UAC.