Clevidipine for hypertension treatment during laparoscopic adrenalectomy for pheochromocytoma in a dog.

An 11-year-old, 8 kg, castrated male dog was presented for adrenalectomy, after being diagnosed with pheochromocytoma by identification of elevated urine metanephrines. Phenoxybenzamine was started 1 month before surgery (2 mg kg, twice daily, orally). Anesthetic premedication was performed with methadone (0.5 mg kg) intramuscularly and maropitant (1 mg kg) subcutaneously. General anesthesia was induced with intravenous (IV) alfaxalone (1 mg kg) and midazolam (0.3 mg kg) and maintained with isoflurane in oxygen delivered through a circle breathing system. Dexmedetomidine (0.5 μg kg bolus over 5 minutes, followed by 0.5 μg kg hour), magnesium sulfate (50 mg kg hour for the first hour, followed by 15 mg kg hour) and lactated Ringer's solution (5 mL kg hour) were given IV. Arterial blood pressures were measured invasively. During manipulation of the adrenal gland, systolic and mean arterial blood pressures increased to 240 and 150 mmHg, respectively, and heart rate decreased to 30 beats minute. Clevidipine, a calcium channel blocker, was infused IV at 1-2 μg kg minute, achieving a reduction in mean arterial blood pressure to between approximately 80 and 85 mmHg, with heart rate between 100 and 120 beats minute. Recovery from anesthesia and surgery was uneventful. The dog was discharged from the hospital 3 days after surgery and its clinical status has been stable for 2 years after the procedure. This case report describes the successful treatment of hypertension using clevidipine, a specific arterial vasodilator with fast onset and offset of action and a low incidence of adverse effects.