Suspected brainstem anesthesia following retrobulbar block in a cat

A 10-year-old, male, neutered, domestic shorthair cat was anesthetised for enucleation of a perforated left globe. A retrobulbar injection of local anesthetic (lidocaine/bupivacaine) was performed prior to surgery to provide intra- and postoperative analgesia. Following administration of the injection, the cat developed apnea and heart rate increased. Mechanical ventilation was initiated and surgery went ahead as planned. At the conclusion of surgery, the cat remained apnoeic requiring positive pressure ventilation until spontaneous ventilatory effort resumed. Upon recovery, the cat demonstrated neurological signs including tremors, nystagmus and absent dazzle reflex. These signs were attributed to brainstem anesthesia from the retrobulbar block and fully resolved within 3 h. This is the first report of suspected intrathecal spread of local anesthetic following retrobulbar block in a cat to the authors' knowledge.