title: Assessment of the effects of intramuscular administration of alfaxalone with and without medetomidine in Horsfield's tortoises (Agrionemys horsfieldii).
abstract: OBJECTIVE
  To characterise four different intramuscular (IM) anaesthetic protocols, two with alfaxalone and two with alfaxalone in combination with medetomidine in terrestrial tortoises.
  
  
  METHODS
  Blinded, randomized, cross-over experimental study.
  
  
  METHODS
  Nine healthy adult male Horsfield's tortoises (Agrionemys horsfieldii).
  
  
  METHODS
  Each tortoise was randomly assigned to one of four different protocols: 1) 10 mg kg(-1) alfaxalone; 2) 10 mg kg(-1) alfaxalone + 0.10 mg kg(-1) medetomidine; 3) 20 mg kg(-1) alfaxalone; and 4) 20 mg kg(-1) alfaxalone + 0.05 mg kg(-1) medetomidine. During the experiment, the following variables were recorded: heart rate; respiratory rate; peripheral nociceptive responses; muscle strength; ability to intubate; palpebral, corneal and tap reflexes; and cloacal temperature.
  
  
  RESULTS
  Protocols 1 and 2 resulted in moderate sedation with no analgesia, and moderate to deep sedation with minimal analgesia, respectively. Protocols 3 and 4 resulted in deep sedation or anaesthesia with variable analgesic effect; these two protocols had the longest total anaesthetic time and allowed intubation in 6/9 and 8/9 tortoises respectively. The total anaesthesia/sedation time produced by alfaxalone was significantly increased (p < 0.05) by the addition of medetomidine. There were no significant differences regarding time to plateau phase and duration of plateau phase. Baseline heart rate of 53 ± 6 beats minute(-1) decreased significantly (p < 0.05) with all protocols, and was lower (p < 0.05) in protocols 3 and 4. Heart rate increased after atipamezole administration, but the increase was transient. In two tortoises, extreme bradycardia with no cardiac activity for 10 minutes was observed with protocols 3 and 4.
  
  
  CONCLUSIONS
  Alfaxalone 10 and 20 mg kg(-1) IM can be used for sedation for non-painful procedures. Alfaxalone in combination with medetomidine can be used for deeper sedation or anaesthesia, but the observed respiratory and cardiovascular depression may limit its use.
authors.affiliation: Center for Zoo and Wild Animal Health, Copenhagen Zoo, Frederiksberg C, Denmark.
authors.forename: Lone L
authors.initials: LL
authors.lastname: Hansen
authors.forename: Mads F
authors.initials: MF
authors.lastname: Bertelsen
mesh_terms: D000758:Anesthesia / Q000379:methods / Q000662:veterinary*; D000777:Anesthetics / Q000008:administration & dosage; D019162:Anesthetics, Combined / Q000008:administration & dosage; D000818:Animals; D006993:Hypnotics and Sedatives / Q000008:administration & dosage; D007273:Injections, Intramuscular; D008297:Male; D020926:Medetomidine / Q000008:administration & dosage; D011277:Pregnanediones / Q000008:administration & dosage; D014426:Turtles / Q000601:surgery
chemical_list: D000777:Anesthetics; D019162:Anesthetics, Combined; D006993:Hypnotics and Sedatives; D011277:Pregnanediones; C006477:alphaxalone; D020926:Medetomidine
keywords: Agrionemys horsfieldii; alfaxalone; anaesthesia; chelonian; medetomidine; tortoise