Hansen LL, Bertelsen MF. Assessment of the effects of intramuscular administration of alfaxalone with and without medetomidine in Horsfield's tortoises (Agrionemys horsfieldii).
Vet Anaesth Analg 2013;
40:e68-75. [PMID:
23672199 DOI:
10.1111/vaa.12045]
[Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 02/12/2013] [Indexed: 11/29/2022]
Abstract
OBJECTIVE
To characterise four different intramuscular (IM) anaesthetic protocols, two with alfaxalone and two with alfaxalone in combination with medetomidine in terrestrial tortoises.
STUDY DESIGN
Blinded, randomized, cross-over experimental study.
ANIMALS
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.
CONCLUSION AND CLINICAL RELEVANCE
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.
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