Chapter 21: Table of Contents
Initial emergency treatment of patients presented for acute collapse or severe respiratory distress is critical. Oxygen is the mainstay of therapy. Mild sedation may also improve breathing by reducing the stress of being in respiratory distress. If the collapse is severe, providing oxygen via a mask or nasopharyngeal canula may not be sufficient. In a crisis, it is best to quickly sedate and intubate the patient in order to provide an airway. If intubation is not successful at improving breathing and oxygenation then collapse beyond the endotracheal tube, severe mainstem bronchus collapse or small airway disease should be considered. Administration of a single dose of dexamethasone (0.25 mg/kg iv) is typical to reduce airway inflammation and edema.
Unless a patient is unable to be extubated after a crisis, medical management is always attempted before considering surgery. Medical therapy should include weight loss, removal of dust, smoke and allergens from the environment, wearing a harness rather than a neck collar, keeping the dog in a cool environment during warm, humid weather, reducing excitement and exercise. In winter, providing humidified air may also be beneficial. For dogs that are not very clinical and are exacerbated with exercise and stress, this might be sufficient, at least initially.
In more severe cases or those that presented in a crisis, antitussives (hydrocodone, butorphanol), sedatives and anxiolytics (acepromazine, trazodone), bronchodilators and possibly corticosteroids are often required. My favorite combination of drugs includes hydrocodone (0.25 mg/kg po q6-8hrs but can go as high as 1mg/kg q6-8h; we use the liquid suspension) and tracheal elixir (compounded by Chiron; 0.22-0.44 ml/kg q 8hrs- also a liquid) +/- trazodone (serotonin modulator; 2-4 mg/kg q12hrs) as needed for anxiety or when expected stressful events can be anticipated (travel, visitors, etc.). I typically add prednisone (1-2 mg/kg q24hrs for 5-7 days and then wean over a week or two) when coughing. Some clinicians like using a cortisone inhalant to reduce inflammation and cough. Antibiotics are not typically warranted unless there is evidence of pneumonia, or bacterial tracheal infection or if stenting is pursued but in some cases, response to antibiotic is noted. Doxycycline is a good empiric choice.
A response rate to medical management of up to 70% has been reported in the literature. (White 1994) If medical therapy controls the clinical episodes, I do not proceed with intervention at this time. If an animal fails aggressive medical management, has a poor quality of life, or progressively stops responding to medical management despite maxing out the drug doses, then I consider more invasive options such as tracheal stenting. Animals that present in respiratory distress that cannot be controlled medically, especially if they have a history of collapse, syncope, or severe exercise intolerance with minimal cough are potentially good candidates for immediate stenting. Patients should be assessed for co-morbidities (e.g. heart and lower airway disease) that could affect response and prognosis.
No procedure has been shown to truly delay the progression of disease. Surgical extraluminal stenting and interventional intraluminal stenting are considered palliative techniques that can improve quality of life but the prognosis remains guarded for patients with severe collapse; especially if collapse of the main stem bronchi is present (~50% of patients). Owners must also consider the fact that dogs undergoing tracheal stenting will typically continue to require medical management for life and that complications can develop, some of which are serious. Stenting is a great option but it is not the answer to all of our wishes.