Laparoscopic ovariectomy under general anesthesia was planned in a 10-year-old, 146 kg,
apparently healthy female African lion (
Panthera leo
). The lion was
immobilized via intramuscular darts containing midazolam (0.033 mg/kg), medetomidine (50
µg/kg) and ketamine (2.5 mg/kg), and intubated using an endotracheal tube (16 mm internal
diameter). The anesthesia was maintained using sevoflurane (0.9–2.1% end-tidal
concentration), in combination with remifentanil (0.1 µg/kg/min) and ketamine (11
µg/kg/min) at a constant rate infusion (CRI), with Hartmann’s solution (5 mL/kg/hr).
Surgery was conducted with stable vital signs, but hypotension (mean arterial blood
pressure 55 mmHg) developed, requiring dobutamine treatment. The hypotension was
effectively controlled by adjusting dobutamine from 5 µg/kg/min to 0.2 to 0.3 µg/kg/min.
This case suggests possibilities that dosages in this range can be clinically useful for
peri-anesthetic hypotension in lions.