What is the scientific justification for the use of nasal strips on racehorses? Preliminary studies performed at Kansas State University (KSU) showed that the Band-Aid-like products, which are marketed by CNS Inc., make breathing easier for equine athletes during strenuous exercise, writes Stephanie L. Church in The Horse.
"The horse is a phenomenal athlete," said Dr. Howard Erickson, a professor of physiology at KSU. During exercise, according to Erickson, "a horse's cardiac output is up to 300 liters per minute; that is 1 1/2 50-gallon oil drums."
When that much blood has to circulate and exchange quickly through the lungs and all the tiny vessels of the respiratory system, the pressures on the vessels are much higher than in other species. Capillaries break, causing exercise-induced pulmonary hemorrhage. This problem is characterized by pulmonary hypertension, edema (collection of fluid) in the gas exchange region of the lung, rupture of the pulmonary capillaries, intra-alveolar hemorrhage, and the presence of blood in the airways.
The nasal strip, which is sold under the commercial name FLAIR, is about the size of an index card. Placed 1 1/2 inches above a horse's nostrils, it contains three springs that provide reinforcement for the unsupported, loose tissue on the sides of the nose. This nasal tissue, unsupported, can impede the intake of air; 50% of total pulmonary resistance results from the nasal passages during quiet breathing and exercise in the horse.
At KSU, the strips were evaluated in seven geldings--six Thoroughbreds and one Quarter Horse. Each horse completed two runs on a treadmill, one with a nasal strip and one without (control), in random order. Results were obtained by counting the number of red blood cells present in bronchial lavage fluid after the run.
"The two horses with the most severe hemorrhage (initially) had the largest reduction (of red blood cells in their lavage fluid)," said Erickson. The number of red blood cells was reduced, on average, by more than 30% with the strip, and the two most aerobically fit horses had a reduction in oxygen consumption (and carbon dioxide production).
KSU plans to study the FLAIR strips next with an ultrasonic flow meter. The equipment will be able to monitor air flow from each nostril and calculate the resistance of the flow, esophageal pressure, and pressure swings as they relate to respiration/stride frequency.
One potential problem with the strips is they could come loose and flap in the breeze, disturbing the horse or surrounding horses in a competitive situation. But according to Erickson, that scenario is not likely to occur often because the adhesive is strong.