Severe cardiovascular depression in a cat following a mandibular nerve block with bupivacaine.

Abstract

OBSERVATIONS: A 12 year old cat was presented for anaesthesia to remove a mandibular squamous cell carcinoma. After intramuscular premedication with dexmedetomidine and methadone, anaesthesia was induced with alfaxalone, administered intravenously (IV) to effect, and maintained with isoflurane vaporized in oxygen, following oro-tracheal intubation. Approximately 5 minutes after performing a mandibular nerve block with 1.16 mg kg(-1) of bupivacaine, the cat developed severe cardiovascular depression. Anaesthetic delivery was discontinued and cardiopulmonary resuscitation instituted. Drug administration consisted of atropine (0.02 mg kg(-1) IV, repeated three times), followed by atipamezole (0.08 mg kg(-1) IV). Dobutamine was subsequently administered (1 μg kg(-1) minute(-1) IV) until cardiovascular performance was considered satisfactory. During recovery from anaesthesia the cat exhibited seizure-like activity, which was controlled by a variable rate infusion of propofol. The cat made an uneventful recovery following discontinuation of propofol infusion, without residual neurological signs, and the surgical procedure was postponed. CONCLUSIONS: This clinical report describes successful management of cardiovascular and neurological complications following a mandibular nerve block with bupivacaine in a cat. Although treatment was successful, the role played by the drugs administered during resuscitation remains uncertain.