A 7-year-old female intact Pomeranian presented to the Cornell Emergency Service for evaluation of penetrating thoracic wounds and bilateral pneumothorax from a dog attack. On presentation, the patient was bright, alert, responsive but painful and in respiratory distress. Paradoxical breathing pattern was noted caudal to the left axilla. Lateral thoracotomy was performed uneventfully to assess the wound extent. However, the patient experienced severe acute hypoventilation upon discontinuation of anesthesia and mechanical ventilation, resulting in severe mixed acidosis and central neurologic deficits. Euthanasia was elected due to her extremely poor prognosis. Several causes disrupting normal respiratory mechanics and gas exchange likely contributed to her ultimate respiratory failure, including her initial thoracic trauma, secondary pulmonary injuries, tissue inflammation from thoracotomy, and general anesthesia.