June 2021

In today’s VETgirl online veterinary continuing education blog, Dr. Kathryn M. Slaughter-Mehfoud, DVM, MPH reviews how to perform an equine emergency tracheostomy in the field. If you are about to see a horse with an upper airway obstruction, a temporary tracheostomy must be performed immediately. She is currently an equine surgical resident at University of Illinois.

How to Perform an Equine Emergency Tracheostomy in the Field

By Kathryn M. Slaughter-Mehfoud, DVM, MPH

The hysterical phone call from an owner yelling “My horse can’t breathe!” always gets the practitioner’s adrenaline and truck racing to the emergency. Upper respiratory obstruction is life-threatening to the horse and a temporary tracheostomy must be performed expediently.

Upon arriving at the emergency, quickly confirm the horse is in respiratory distress and in need of a temporary airway. If you’re lucky, you’ll be able to create a temporary tracheostomy while the horse is standing. Place the horse in stocks, if stocks are available and your assessment concludes it is unlikely the patient will collapse. If you think the horse has complete upper airway obstruction and is on the verge of collapse, perform the procedure in a safe area, such as level grass without nearby objects. Sedate the horse intravenously with a short-term alpha-2 adrenergic receptor agonist, such as xylazine. If your assessment of the patient determines you have time to aseptically prepare the surgical site, strict asepsis protocols should be followed. Aseptic preparation of the surgical site is commonly not performed if the patient’s upper airway is completely obstructed and collapse is imminent. Likewise, if you have time to aseptically prepare the surgical site, you have time to inject local anesthesia into the subcutaneous tissues and underlying paired sternothyrohyoideus muscles.

The surgical approach is made on the ventral midline at the junction of the proximal and middle thirds of the cervical trachea. The proximal and middle third junction is optimal for placement because the trachea is most superficial in this region. An approximately 10-cm incision is made down to the paired sternothyrohyoideus muscles. These paired muscle bellies are separated and, if available, a self-retaining retractor inserted between the muscles to expand your field of view. Palpation between the muscle bellies reveals the trachea, which is distinguishable by its fibrocartilaginous rings. Using a #10 scalpel blade, a transverse incision is made between two identifiable tracheal rings. It is important the incision not be greater than 50% of the circumference of the trachea. Once the tracheal incision has been made, insert the tracheostomy tube into the tracheal lumen, and BREATHE! Whew! This quick, sometimes daunting, but frequently rewarding procedure can make the veterinarian hold their breath until they hear the deep, thankful breath of a horse which can now adequately breathe.

Unfortunately, luck isn’t always on your side and you may have to perform a temporary tracheostomy with the horse in lateral recumbency. In some situations, the horse is so frantic and the situation is so dangerous, you may have to wait for the horse to collapse in order to safely perform a temporary tracheostomy. This procedure is more challenging to perform in lateral recumbency for multiple reasons. With a horse in lateral recumbency, the trachea shifts within the neck and doesn’t maintain a consistent vertical location. Also, expediency is mandatory as mere additional seconds without oxygenation can produce a fatal outcome. In addition, safety to the veterinarian and owner/handlers is significantly impaired. Recumbent horses can spontaneously kick or attempt to anxiously stand. If available, a skilled, trained assistant is useful to help extend the neck while maintaining a safe working environment.

The most common tracheostomy tubes are self-retaining metal tubes and cuffed silicone tubes. Self-retaining metal tubes are preferred because they don’t require suture and don’t easily dislodge. Silicone tubes are placed in horses with thick neck musculature, such as Draft breeds, because they extend further caudally into the neck. The smaller self-retaining metal tubes are commonly too small for Draft breeds, but in an emergency will suffice until a silicone tube can be inserted or upper airway obstruction is resolved. Silicone tubes are more easily dislodged and require their flanges to be connected and tied with umbilical tape around the horse’s neck. If you don’t have access to a tracheostomy tube, get creative! Life-threatening emergencies require ambition and creativity. Cut the end of a nasogastric tube, cut the tip off a large syringe case, or cut a portion of garden hose and insert it into the airway. Alive horses are the best horses! Once an airway is established, an appropriate tracheostomy tube can be placed later.

The most common complication with tracheostomy tubes is mucoid blockage within the tube. To mitigate mucoid blockage, tracheostomy tubes and the surgical site should be cleaned twice daily. Post-operative complications are reduced with aseptic technique and delicate soft tissue handling, which is often not feasible in a horse with almost complete upper airway obstruction. Broad-spectrum antimicrobials are also strongly recommended due to likely contamination from the emergency nature of the procedure. Tracheostomy tubes must be routinely evaluated for dislodgement, which is more common with silicone tubes and deadly.

After the upper airway obstruction has been appropriately treated, the tracheostomy tube is removed. The horse should be closely monitored for recurrence of upper airway obstruction. The surgical site is cleaned daily and healed by second intention. This isn’t a procedure to treat permanent upper airway obstruction. If the horse has permanent upper airway obstruction, a permanent tracheostomy is recommended for good surgical candidates.

The ideal permanent tracheostomy is performed on a calm, sedated horse which is standing in stocks with aseptic technique, regional anesthesia, and a beautiful 10 cm incision. However, it is likely you will have to perform this procedure in the dirt, no sedation, lacking regional anesthesia, with the creation of a 20 cm incision. Being adaptable to the situation is imperative.

  2. Jon Schwiesow says:

    Very good article, Never did this procedure before, but considered doing this on a strangles patient. Fortunately she recovered before getting a tube. After this article, I would be more likely to try.

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