Patients with mild tears and no more than moderate dyspnea can be treated with conservative medical management2,3 consisting of cage rest and possible oxygen supplementation. Resolution of clinical signs can range from 2 days to 5 weeks.2 Sedative administration may help prevent vocalization.4 Potential sedatives for such cases include butorphanol (0.2-0.4 mg/kg IV), midazolam (0.25 mg/kg IV), acepromazine (0.01-0.03 mg/kg IV or IM), buprenorphine (0.01-0.02 mg/kg IV), and opioid–tranquilizer combinations.
All cats with severe respiratory compromise should be treated surgically.4 Immediate surgery is required in patients with severe dyspnea, open-mouth breathing despite oxygen treatment, or worsening subcutaneous emphysema.4
If possible, in patients with a tracheal tear confirmed before anesthesia, the ventral cervical area and the right thoracic wall should be clipped; this allows for a shorter preparation time while the patient is anesthetized. The surgeon should be present during intubation in case a tension pneumothorax develops and emergent surgery is needed. The anesthetic plan should include a smooth IV induction technique and intubation with an endotracheal tube lumen that is smaller than normal to avoid interference on the trachea during surgery. However, the endotracheal tube should still be long enough to pass below the tear.1,5,7 In cases in which the tear extends to the carina, there is a higher mortality rate during surgery.2,7,8 Cats can be intubated for surgery, although an injectable technique may be preferred.
Of note, death can occur during surgery in cases in which it is not possible to ventilate the cat due to the distal location of the tear.2,5,8 Tracheal tears may allow for the inhalant to escape from the respiratory tract and into the surrounding environment; this will expose team members to the inhalant and can make it difficult to maintain an appropriate anesthetic plane. Once the tear has been repaired, the cuff can be inflated until no gas is detected escaping from around the endotracheal tube when a positive pressure of 15 cm H2O is applied via rebreathing bag compression.5 If using an injectable anesthesia, inflating the cuff may not be necessary unless positive pressure ventilation is required, but cuff placement should be avoided near the area of the repaired tear.
A ventral midline approach should be used, as it may be necessary to split the first several sternebrae to repair ruptures in the thoracic inlet. All reported tears have occurred at the junction of the tracheal rings and trachealis muscle.6 The trachea can be repaired with simple interrupted or simple continuous sutures with absorbable or nonabsorbable material.2,4 When performing surgical repairs, care should be taken to protect the recurrent laryngeal nerves during tracheal exposure.3
Resolution of subcutaneous emphysema can take 1 to 6 weeks (average, 2 weeks).4 Resolution is slow because absorption of air depends on the diffusion gradient of nitrogen, which is small.4 To speed the absorption, treatment with 95% oxygen over 4 hours has been used in humans and may be helpful in cats.4 This treatment decreases the partial pressure of nitrogen in the blood and promotes diffusion of nitrogen from the interstitium into the blood4; however, this is not commonly performed in cats because of the difficulty of providing 95% oxygen via methods other than intubation and anesthesia.