Abstract

Thirteen captive cheetahs (Acinonyx jubatus) were immobilized for annual routine examination. The cheetahs were given 35±3.7 μg/kg of medetomidine (MED) + 0.2±0.02 mg/kg of butorphanol (BUT) and 0.15±0.02 mg/kg of midazolam (MID) intramuscularly (MBMz).

Once recumbent, the cheetahs were transported to the hospital and physiologic data were measured every 5 min for 60 min (HR, RR, SpO₂, blood pressure, end-tidal CO₂, and temperature) while breathing room air. Weight, EKG, arterial blood gases and cardiac output were also measured. If arousal occurred before 60 min, a ketamine supplement was given intravenously. After this time, isoflurane was administered and annual examination procedures were performed. At the end of the procedures, atipamezole (175 μg/kg), flumazenil (6 μg/kg), and naltrexone (0.25 mg/kg) were given intramuscularly.

This combination produced a fast and smooth induction (5±1 min), adequate sedation for transport and minor procedures (MBMz anesthesia time 70±16 min), and quick recovery. Hypertension occurred in all animals. Ventilation and oxygenation were good on room air (SaO₂ 91.7±2.5%, PCO₂ 39.4±4.5 mm Hg). Pulse oximetry and mucous membrane coloration were not useful for evaluating blood oxygenation with MBMz combination (pale mucous membranes and falsely low SpO₂ values).

MBMz combination seems ideal for field procedures where oxygen may not be readily available and quick recovery and release are desired. It is recommended for short procedures (≤40 min), due to sudden arousal that may occur after that time. For longer procedures, supplemental drugs are recommended (injectable agents or isoflurane in oxygen). Finally, this ketamine-free combination may be beneficial for animals with liver/kidney dysfunction, in which the metabolism and excretion of ketamine may be impaired.