Medetomidine-Ketamine/Atipamezole Anesthesia/Reversal in Wild Arctic Fox Pups in Swedish Lapland
The arctic fox (Alopex lagopus) inhabits the tundra regions of the northern hemisphere. It is circumpolar and breeds north above the treeline. In Sweden, the population is considered endangered of extinction, comprising approximately 40–80 adult individuals during population phases of low density. Free-ranging arctic fox pups (21) were captured during health assessment studies using metal cage live traps. Dens were continuously observed for 24 hr and when a cub was captured, it was immediately removed from the trap and brought to the field camp (100–200 m away). Six pups, 7 wk of age, weighing 1826±47 g (range: 1715–2080 g) were anesthetized with a combination of medetomidine (Zalopine, Orion-Farmos, Turku, Finland, 1 mg/ml, 0.05 mg/kg) associated with ketamine (Ketaset, 100 mg/ml, 2.5 mg/kg). The intramuscular injection rapidly resulted in complete anesthesia with excellent skeletal myorelaxation, lateral recumbency, and loss of pedal, swallowing, palpebral and corneal reflexes in 92 sec (range: 58–150 sec). Pups were immobilized for a mean time of 18±5 min (range: 13–25 min). Rectal temperature decreased and respiratory and cardiac rates increased during anesthesia. Intramuscular administration of 0.25 mg/kg of atipamezole (Atiprin, Orion-Farmos, 5 mg/ml), effectively reversed the effects of this anesthetic combination. All pups were standing within 12±7 min (range: 5–24 min) after reversal. Induction to full recovery lasted 27±5 min (range: 19–36 min). Continuous real time monitoring of pulse rate and percent oxygen saturation of hemoglobin (SpO2) trends were measured with a handheld pulse oximeter N-20PA (Nellcor Puritan Bennett, Pleasanton, CA). All six pups presented stable pulse oximetry profiles. The average of SpO2 values was 89±2% (87–92%). Pulse oximetry and standard anesthetic monitoring procedures indicated no adverse physiologic effects to this drug combination. Following reversal to standing, all pups behaved normally and were returned to their den after full recovery following careful clinical evaluation. All pups were monitored 1 hr, 12 hr, 24 hr and 2 wk post-anesthesia. Although the sample size is small, this reversible neuroleptanalgesic combination proves to be safe and effective in young canids.