Clearing the airway
For years, equine veterinarians Jim Chiapetta, DVM, JD, and Ed Blach, DVM, MS, MBA, were intrigued by a common phenomenon in horses—the nostrils' tendency to collapse during heavy inspiration brought on by strenuous work or exercise. Aware that some human athletes were promoting the use of nasal strips to open airways and increase respiration, the duo developed nasal strips for working horses to similarly improve their performance.
The goal was simple: open the airway to enhance airflow.
Since the equine nasal strips were developed more than 10 years ago, a growing body of research has examined their effectiveness. Susan Holcombe, VMD, MS, PhD, DACVS, DACVECC; Edward Robinson, BVetMed, PhD; and colleagues at Michigan State University examined nasal passages using videoendoscopy (in one horse) and noted that the nasal strip did open the airway.1 They also carefully measured airway pressures, but they did not quantify exercise-induced pulmonary hemorrhage—bleeding in the lungs—either via endoscopy or bronchoalveolar lavage (BAL).
Nonetheless, their findings revealed a significant effect on airway mechanics during maximal exercise.1 Peak tracheal inspiratory pressure and inspiratory airway resistance were reduced when horses wore the nasal strips while exercising at speeds at and above those that yielded their maximal heart rates. Analysis of these results suggests that the nasal strip increases the diameter of the nasal passage and stability of the soft tissue structures in the nose.
This conclusion was supported by results of endoscopic examination of the nasal valve in one of the horses, which revealed that the strip tented the skin over the nasal valve, pulled the dorsal conchal fold laterally and increased the cross-sectional area of the dorsal meatus, resulting in decreased airway resistance during inspiration. The team concluded that "the nasal strip probably decreases the amount of work required for respiratory muscles in horses during intense exercise and may reduce the energy required for breathing in these horses."1 This was an observation that was substantiated using rigorous laboratory science.