title: A Double-Blinded, Randomized Comparison of Medetomidine-Tiletamine-Zolazepam and Dexmedetomidine-Tiletamine-Zolazepam Anesthesia in Free-Ranging Brown Bears (Ursus Arctos).
abstract: We compared anesthetic features, blood parameters, and physiological responses to either medetomidine-tiletamine-zolazepam or dexmedetomidine-tiletamine-zolazepam using a double-blinded, randomized experimental design during 40 anesthetic events of free-ranging brown bears (Ursus arctos) either captured by helicopter in Sweden or by culvert trap in Canada. Induction was smooth and predictable with both anesthetic protocols. Induction time, the need for supplemental drugs to sustain anesthesia, and capture-related stress were analyzed using generalized linear models, but anesthetic protocol did not differentially affect these variables. Arterial blood gases and acid-base status, and physiological responses were examined using linear mixed models. We documented acidemia (pH of arterial blood < 7.35), hypoxemia (partial pressure of arterial oxygen < 80 mmHg), and hypercapnia (partial pressure of arterial carbon dioxide ≥ 45 mmHg) with both protocols. Arterial pH and oxygen partial pressure were similar between groups with the latter improving markedly after oxygen supplementation (p < 0.001). We documented dose-dependent effects of both anesthetic protocols on induction time and arterial oxygen partial pressure. The partial pressure of arterial carbon dioxide increased as respiratory rate increased with medetomidine-tiletamine-zolazepam, but not with dexmedetomidine-tiletamine-zolazepam, demonstrating a differential drug effect. Differences in heart rate, respiratory rate, and rectal temperature among bears could not be attributed to the anesthetic protocol. Heart rate increased with increasing rectal temperature (p < 0.001) and ordinal day of capture (p = 0.002). Respiratory rate was significantly higher in bears captured by helicopter in Sweden than in bears captured by culvert trap in Canada (p < 0.001). Rectal temperature significantly decreased over time (p ≤ 0.05). Overall, we did not find any benefit of using dexmedetomidine-tiletamine-zolazepam instead of medetomidine-tiletamine-zolazepam in the anesthesia of brown bears. Both drug combinations appeared to be safe and reliable for the anesthesia of free-ranging brown bears captured by helicopter or by culvert trap.
authors.affiliation: Department of Forestry and Wildlife Management, Inland Norway University of Applied Sciences, Campus Evenstad, Elverum, Norway.
authors.forename: Núria
authors.identifier: http://orcid.org/0000-0002-2682-7300
authors.initials: N
authors.lastname: Fandos Esteruelas
authors.affiliation: RGL Recovery Wildlife Health & Veterinary Services, Saskatoon, Saskatchewan, Canada.|Department of Veterinary Pathology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Marc
authors.initials: M
authors.lastname: Cattet
authors.affiliation: Department of Environmental and Health Studies, University College of Southeast Norway, Porsgrunn, Norway.|Department of Integrative Biology and Biodiversity Research, University of Natural Resources and Applied Life Sciences, Vienna, Austria.
authors.forename: Andreas
authors.initials: A
authors.lastname: Zedrosser
authors.affiliation: fRI Research, Hinton, Alberta, Canada.
authors.forename: Gordon B
authors.initials: GB
authors.lastname: Stenhouse
authors.affiliation: Department of Forestry and Wildlife Management, Inland Norway University of Applied Sciences, Campus Evenstad, Elverum, Norway.
authors.forename: Susanne
authors.initials: S
authors.lastname: Küker
authors.affiliation: Department of Forestry and Wildlife Management, Inland Norway University of Applied Sciences, Campus Evenstad, Elverum, Norway.
authors.forename: Alina L
authors.initials: AL
authors.lastname: Evans
authors.affiliation: Department of Forestry and Wildlife Management, Inland Norway University of Applied Sciences, Campus Evenstad, Elverum, Norway.|Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences, Umeå, Sweden.
authors.forename: Jon M
authors.initials: JM
authors.lastname: Arnemo
mesh_terms: D000416:Alberta; D000758:Anesthesia / Q000662:veterinary*; D000777:Anesthetics / Q000494:pharmacology; D000818:Animals; D000835:Animals, Wild; D001831:Body Temperature / Q000187:drug effects; D002245:Carbon Dioxide / Q000097:blood; D066264:Datasets as Topic; D020927:Dexmedetomidine / Q000494:pharmacology; D004311:Double-Blind Method; D004338:Drug Combinations; D006439:Hemodynamics / Q000187:drug effects; D008297:Male; D020926:Medetomidine / Q000494:pharmacology; D010100:Oxygen / Q000097:blood; D010102:Oxygen Inhalation Therapy; D010313:Partial Pressure; D012119:Respiration / Q000187:drug effects; D013312:Stress, Physiological / Q000187:drug effects / Q000502:physiology; D013315:Stress, Psychological / Q000503:physiopathology; D013548:Sweden; D013992:Tiletamine / Q000494:pharmacology; D001503:Ursidae / Q000502:physiology*; D015041:Zolazepam / Q000494:pharmacology
chemical_list: D000777:Anesthetics; D004338:Drug Combinations; C006131:tiletamine, zolazepam drug combination; D002245:Carbon Dioxide; D013992:Tiletamine; D020927:Dexmedetomidine; D015041:Zolazepam; D020926:Medetomidine; D010100:Oxygen