An 11-year-old cocker spaniel underwent bronchoscopic removal of a carcinoma that was protruding from the mucosal surface of the right main stem bronchus and was blocking approximately 80% of the bronchial lumen. The case presented challenges: The surgeon would be working with a 9.6-mm diameter endoscope in the trachea, gas flow in the right bronchial tree would have to be avoided to decrease risk for aspiration of mass debris during resection, and avoiding an oxygen-rich gas mixture in the trachea would be necessary to minimize the risk for a flash fire when using electrocautery. These requirements urged the authors to perform the procedure with a "one-lung ventilation" technique that utilized an endobronchial tube placed just distal to the carina into the left, unaffected lung. The patient did experience decreased PaO2 and increased PaCO2, so the surgeon adjusted the ventilation by changing the respiratory rate, peak inspiratory pressure, and positive end expiratory pressure (PEEP). By adjusting these parameters, the surgeon could proceed without the patient becoming hypoxic. Hypercapnia could not be avoided despite an increase in respiratory rate. In conclusion, this technique allowed the surgeon to successfully remove the tumor with minimal mucosal damage in the mainstem bronchus. It increased respiratory rates while maintaining a low tidal volume, thus preventing alveolar overdistention. The use of low-pressure PEEP and controlled ventilation was beneficial and the dog was discharged 4 days after surgery. However, labored breathing recurred 1 month later, and the owner requested euthanasia.
COMMENTARY: This article describes a technique in which 2 devices are inserted into a dog's trachea to remove a tumor in the mainstem bronchus, while avoiding potentially hazardous complications, like combustion from cautery mixed with oxygen from the inhalant anesthesia. One-lung ventilation is used in human medicine to ventilate an isolated lung field and facilitate certain types of pulmonary or thoracic surgery during emergency situations requiring lung separation. Hypoxia is rare, but some literature suggests that one-lung ventilation induces inflammation in the ventilated lung. This dog recovered uneventfully from the procedure, and the article does a fantastic job of describing the technique, even for practitioners who don't routinely perform closed thoracic surgery.
Endoscopic removal of a bronchial carcinoma in a dog using one-lung ventilation. Mosing M, Iff I, Moens Y. VET SURG 37:222-225, 2008.