Thymectomy in a cat with myasthenia gravis: a case report focusing on perianaesthetic management.

An 8 years old male persian cat with a diagnosis of myasthenia gravis was scheduled for transternal thoracotomy. An anterior mediastinal mass, suspected to be a thymoma, had to be resected. Progressive paraparesis and reduced ocular reflexes and menace response were the main clinical features. At the preoperative examination the cat appeared free of significant myocardial or respiratory diseases. The possibility of compromised respiratory function due to muscle weakness was addressed by the choice of a balanced anesthesia protocol without the use of muscle-relaxants. Intravenous induction was followed by intubation, administration of isoflurane in oxygen and ventilatory support. Thorough cardiorespiratory monitoring was performed during anaesthesia. Epidural morphin was given to reduce the amount of inhalation agent required to maintain anaesthesia and supplemental intravenous analgesia was given. At the end of the surgery, intrapleural bupivacaine was administered to help controlling poststernotomy pain, while reducing the need for systemic analgesics. Although rapid returning of swallowing reflex and spontaneous breathing followed the disconnection from the anaesthetic circuit, the cat needed to breath oxygen enriched air to maintain a normal hemoglobin saturation in the early postoperative phase.