The Dynamic Endoscope Explained

In order for a racehorse to successfully speed down the track, a jumper to navigate a quick and clear round, or a dressage horse to perform a picture-perfect test, the horse must have a healthy respiratory system.

Regardless of discipline or level of training, it is key to ensure a horse is breathing properly for its overall wellbeing. 

If a horse is having respiratory problems, there are several ways that a veterinarian can investigate the issue. One of the most effective tools is a dynamic endoscope, a video recording device that can be worn by the horse during exercise to observe the respiratory system while they are active.

Respiratory Specialist, Dr. David Priest of Palm Beach Equine Clinic (PBEC), focuses on upper airway diagnosis and surgery for equine athletes and often uses a dynamic endoscope to evaluate his patients.

The equine respiratory system is responsible for bringing large amounts of oxygen in and out of the lungs, where it is then used to fuel complex bodily processes. It comprises two sections, the upper and lower airways. The upper airway begins with the nostrils and extends through the larynx and into the trachea. The lower airway is made up of the lungs, which rest behind the shoulder, extend up the back, and reach toward the end of the ribcage. 

“Even a small decrease in lung capacity or impingement on airflow can have dramatic effects on overall health and performance,” described Dr. Priest. “Problems affecting the upper and lower airways may overlap but can include coughing or odd noises, exercise intolerance, nasal discharge, or labored breathing at rest.”

During exercise, the amount of air moved in and out of the horse increases proportionately to how hard the horse is working. The more demanding the work, the more oxygen must be used. A horse at rest inhales approximately 3.5 liters of air per second (L/s), and increases exponentially to 70 L/s at maximum exertion, according to Dr. Priest.

“If a horse is showing signs of difficulties in its respiratory health, veterinarians may use radiography or ultrasound to image the lungs,” explained Dr. Priest. “Going beyond greyscale images [such as radiographs], the veterinarian may also evaluate the upper respiratory tract through the use of an endoscope. An endoscope is a medical device with a small lens on the end that can be inserted through the horse’s nostril to view the horse’s pharynx.”

If a horse is having trouble breathing only while working, it is necessary for a veterinarian to be able to evaluate them while they are active. To perform that assessment, a dynamic endoscope is used. This allows veterinarians to examine the horse’s pharynx, epiglottis, and trachea in motion. The dynamic endoscope will detect throat abnormalities and provide more information on respiratory issues or problems that are not seen when the horse is resting. 

“The soft tissue structures of the horse’s upper airway experience a significant amount of force when the horse is exercising,” remarked Dr. Priest. “There is also a significant difference in resting and exercising forces, and this causes the upper airway tissues to appear anatomically normal at rest, even if they are functioning abnormally during exercise.”

A dynamic endoscope is often used with horses that have recurrent laryngeal neuropathy, commonly known as “roaring.” Recurrent laryngeal neuropathy restricts the amount of air able to reach the lungs through the horse’s upper respiratory system. This is a useful tool to diagnose the problem and also to evaluate the effectiveness of the surgery.

Respiratory difficulties during exercise can have a significant negative impact on a horse’s health and performance. A dynamic endoscope is a valuable and informative tool in Equine Sports Medicine. Once the issue is identified, there are several treatment or surgical options to address specific respiratory illness. If your horse is making an abnormal noise during exercise, or if you suspect breathing problems, contact your veterinarian to make sure your horse is performing at its best.

Visit equineclinic.com for more information on the equine respiratory system and the use of a dynamic endoscope.