Background:
The anaesthetic management of adrenalectomies for phaeochromocytoma excision, a catecholamine secreting tumour, is challenging due to the potential for fatal complications following severe haemodynamic variations, including hypertensive crisis following tumour manipulation or sympathetic stimulation, but also severe hypotension and volume depletion post resection.
Case Description:
An 11kg, 15-year-old male neutered Jack Russel Terrier, with mitral valve disease (MVD) stage B2, was referred for adrenalectomy for phaeochromocytoma resection. The patient was administered per os prazosin 0.11mg/kg twice a day and amlodipine 0.125mg/kg once a day for preoperative stabilisation. On the day of surgery, the dog received maropitant 1mg/kg intravenously (IV) and was premedicated with 0.2mg/kg methadone IV. Anaesthesia was induced with alfaxalone 1mg/kg IV and midazolam 0.2mg/kg IV and maintained with a partial intravenous anaesthesia using sevoflurane in 70% oxygen and constant rate infusions of dexmedetomidine 0.5μg/kg/h and maropitant 100μg/kg/h. After induction of anaesthesia, the dog was mechanically ventilated, and a transversus abdominal plane block was performed with ropivacaine 0.2%. The dog remained remarkably stable with a single, self-limiting, hypertension episode recorded intraoperatively. Postoperative rescue analgesia consisted in methadone and ketamine. The dog was discharged 48h after surgery, but persistent hypertension was reported at suture removal.
Conclusion:
The use of a low dose dexmedetomidine CRI, a maropitant CRI and a TAP block provided stable perioperative haemodynamic conditions for phaeochromocytoma excision in a dog.
Key words: Anaesthesia, Dexmedetomidine, Maropitant, Phaeochromocytoma, TAP
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