ANESTHESIA OF AQUARIUM-HOUSED WALRUS (ODOBENUS ROSMARUS): A CASE SERIES

• Published in: Journal of Zoo and Wildlife Medicine
• Main Authors: Johanna Kaartinen, Stéphane Lair, Michael T. Walsh, Patrick Burns, Marion Desmarchelier, Jessica M. Pang, Daniel S.J Pang
• Format: Text
• Language: English
• Published: American Association of Zoo Veterinarians 2018
• Subjects: Odobenus rosmarus; walrus*
• Online Access: https://doi.org/10.1638/2017-0167.1

Walruses are a challenging species to anesthetize as a result of their large mass, limited access for drug delivery, unique physiology, and small number of reports describing anesthetic procedures. Three aquarium-housed walruses (Odobenus rosmarus) ranging in age from 3 to 11 yr old (344–1,000 kg) were anesthetized for dental or ophthalmic surgical procedures, with one animal anesthetized twice and one anesthetized three times. Preanesthetic medication was with intramuscular midazolam (0.1–0.2 mg/kg) and meperidine (2–3 mg/kg). A catheter was placed in the extradural intravertebral vein, and anesthesia was induced with propofol to effect. Orotracheal intubation was performed and anesthesia maintained with isoflurane in oxygen using a circle breathing system connected to a ventilator. Intermittent positive pressure ventilation was used in all procedures. For the ophthalmic surgery, the neuromuscular blocking agent, cisatracurium, was given intravenously to provide a central eye and optimal surgical conditions. The neuromuscular block was antagonized with edrophonium. Total anesthesia times ranged from 1.5 to 6 hr. Midazolam and meperidine were antagonized with flumazenil and naltrexone, respectively, in five of six cases. Nonsteroidal anti-inflammatory agents were provided for analgesia. Recoveries were calm and uneventful. The described anesthetic protocols and case management were successful under the conditions encountered.