Pneumothorax in a dog after surgical attenuation of portosystemic shunt

A 2-year-old, 2.6 kg, intact male Maltese dog was anaesthetized for the surgical attenuation of an extrahepatic portosystemic shunt. The anaesthesia protocol consisted of dexmedetomidine, fentanyl, propofol, and isoflurane. Near the end of the surgery, acute changes in respiration, including an increased respiratory rate, hypoventilation, and fluctuating oxygen saturation of arterial haemoglobin measured by pulse oximetry, were observed. Thoracic radiography confirmed pneumothorax with earlier diagnosis confounded by uncertainty over interpretation of clinical signs, not considering the possibility of a diaphragmatic tear associated with cranial abdominal surgery, and limited experience with thoracic ultrasound. Following needle thoracocentesis, the dog recovered uneventfully and was discharged from the hospital 4 days postoperatively. The suspected cause of the pneumothorax was a diaphragmatic tear during dissection to better visualize the shunt vessel. Morbidity and mortality rounds were held and inadequate communication and trainee supervision were identified as contributing factors. This case report discusses the potential aetiology of perioperative pneumothorax and aims to raise awareness among surgeons and anaesthetists regarding the risk of pneumothorax during portosystemic shunt attenuation.