“Respiratory emergencies can result in panic from all parties, because it turns out … breathing is important,” began Jamie Kopper, DVM, PhD, Dipl. ACVIM, ACVECC, at the 2021 Veterinary Meeting and Expo held virtually and in Orlando, Florida.
With little time to act, Kopper said veterinarians called upon to help horses struggling to breathe must arrive organized, prepared, and confident.
Locate the Blockage
The first step for providing the patient with relief in is locating the blockage. “There’s only one question to ask yourself at this stage: Is the problem coming from the upper or the lower respiratory tract?” said Kopper, who’s a large animal internist and criticalist at Iowa State University, in Ames.
Causes of upper-respiratory blockages can include rattlesnake bites resulting in occlusion of the nostrils due to swelling, laryngeal masses, retropharyngeal lymph node enlargement (i.e., Streptococcus equi equi infection), Kopper said.
“If you determine the origin is in the upper respiratory tract, that’s all you need to know to pull out your tracheotomy kit (to create an opening in the trachea, or windpipe, to permit breathing),” she said. “This isn’t the time to find out if the obstruction is in the pharynx, larynx, or nasal passage. It’s time to bypass all of it and create a new point of entrance for air.”
Tracheotomy Kit and Tips
Kopper recommends keeping a dedicated tracheotomy kit in the vet truck to avoid scrambling for supplies when time is scarce. The kit should include:
- Cordless clippers;
- Pre-made scrub;
- Needles and syringes;
- Local anesthetic;
- Exam and sterile gloves;
- Scalpel blade; and
- Tracheal retainer (a 60-cc syringe with the tip cut off will do in a pinch).
To ensure a successful tracheotomy, Kopper shared the following tips:
- Positioning: Aim for the junction between the proximal and middle third of the neck, taking care to avoid the jugular vein and carotid artery.
- Procedure: Using a scalpel blade, dissect through the (anesthetized) skin, sternothyroid muscle, and annular ligament between two tracheal rings to gain access to the tracheal lumen. Do not cut through the tracheal rings themselves.
- Timing: For the veterinarian wondering if he or she might be jumping the gun by opening the trachea, Kopper’s answer is simple: “If you have to ask yourself whether or not a tracheotomy is warranted, the answer is always ‘yes!’” She emphasized the importance of having the trachea open before the horse begins to suffocate and panic. “If that happens, for your own safety, you need to step away and wait for the animal to lose consciousness and drop to the ground before resuming your work,” she said. It’s important to remember that, when it comes to tracheotomies, an hour too early is better than a minute too late.
Dealing With Lower Respiratory Tract Blockages
Moving on to the lower respiratory tract, Kopper identified pleural pneumonia (infection of the lung lining), acute exacerbation of equine asthma, and penetrating trauma to the thorax (chest area) as common causes of respiratory blockages.
Acute crisis management of these cases can include bronchodilation in the asthmatic patient and ventral thoracocentesis (a chest tap to get fluid for laboratory analysis if necessary) in a horse with pleural pneumonia. Thoracentesis has both diagnostic and therapeutic purposes, as it relieves fluid accumulation and provides a sample to send out for cytology, lactate, and glucose.
In the case of penetrating thoracic trauma, the veterinarian might perform thoracocentesis in the dorsal (lower) thorax to relieve air accumulation. This is necessary if the foreign object is creating a one-way valve into the thorax, trapping air inside. In severe cases, a thoracotomy (creating an opening in the chest wall) might even be necessary.
“Whether you find air or fluid in the thorax–or anything else that doesn’t belong there–the best thing you can do for the horse is to get it out,” Kopper said.