Suspected systemic gas embolism associated with lung tissue perforation caused by a previously inserted chest drain in a dog.

Objective: To report a case of systemic gas embolism associated with removal of a chest drain perforating a lung lobe in a dog undergoing sternotomy under general anesthesia and intermittent positive pressure ventilation.

Case Summary: An 8-year-old Cocker Spaniel underwent an exploratory thoracotomy via median sternotomy for surgical management of pyothorax that was treated conservatively for 7 days prior to referral following bilateral chest drain placement. The surgical procedure consisted of a subphrenic mediastinectomy and pericardiectomy. During surgery, it became apparent that the right drain was perforating the right middle lung lobe. Sudden desaturation and rapid hemodynamic deterioration occurred after the drain was removed. A systemic gas embolism was suspected on the basis of clinical signs and results of an arterial blood gas analysis, and immediate supportive treatment was started with an adequate response. Once the surgical procedure was completed, a clear "mill wheel" sound was audible on cardiac auscultation and point-of-care cardiac ultrasound confirmed the presence of gas bubbles in the cardiac chambers. The dog recovered from anesthesia and was managed in the intensive care unit where arterial blood gas analyses were nearly normal and the dog made a full recovery.

New Or Unique Information Provided: In people, there are reports of fatal air embolism related to the use of chest drains. To our knowledge, this is the first case report in dogs of a systemic gas embolism during open-chest surgery caused by a chest drain perforating a lung lobe. Immediate recognition and aggressive treatment of this life-threatening condition should be provided in order to achieve a favorable outcome.