Anesthetic Protocols, Associated Challenges, and Successful Outcomes in Spectacled Bears (Tremarctos ornatus), Sloth Bears (Melursus ursinus), and Giant Pandas (Ailuropoda melanoleuca) at the Smithsonian’s National Zoological Park, 1995–2013
Limited publications exist in the literature on spectacled bear (Tremarctos ornatus), sloth bear (Melursus ursinus), or giant panda (Ailuropoda melanoleuca) anesthesia. Between 1995–2013, the Smithsonian’s National Zoological Park recorded a total of 117 anesthetic procedures on captive bear species (41 anesthetic procedures on 4.3 spectacled bears, 32 anesthetic procedures on 3.5 sloth bears, and 44 anesthetic procedures on 3.1 giant pandas). Induction protocols involved some combination of xylazine (n=39), medetomidine (n=46), ketamine (n=96), tiletamine-zolazepam (n=75), and/or midazolam (n=1). The most commonly used protocol for spectacled bears and sloth bears was tiletamine-zolazepam (1.0–3.0 mg/kg), ketamine (1.3–3.0 mg/kg), and medetomidine (0.012–0.016 mg/kg) (n=11 for each species), and for giant pandas it was ketamine (2.1–10.9 mg/kg) and xylazine (0.5–1.1 mg/kg) (n=17). Supplemental injections of ketamine, midazolam, telazol, and/or medetomidine were required to complete inductions in 39 cases. Anesthetic maintenance was most often performed with isoflurane, ketamine, or propofol and anesthesia was reversed with yohimbine, atipamezole and/or flumazenil when indicated. Atropine or glycopyrrolate were often administered to minimize oral secretions. Metoclopramide was given frequently in an attempt to minimize vomiting, with variable effect. Commonly reported complications included perianesthetic vomiting during various anesthetic protocols, and bradycardia and hypertension in response to alpha-2 agonists. Seizure activity was reported in some bears that received ketamine for induction. Hyperthermia occurred very rarely and was associated with prolonged induction times, and hypothermia occurred during prolonged anesthesias. No episodes of spontaneous arousal occurred.