Objective: To characterise the effects of alfaxalone by intramuscular (i.m.) injection in red-eared slider turtles and the influence of body temperature on anaesthetic duration and depth.
Study design: Prospective, randomised part-blinded experimental trial.
Animals: Ten healthy adult female red-eared sliders.
Methods: Each turtle was anaesthetized four times with 10 and 20 mg kg(-1) alfaxalone at 20 and 35°C respectively. Time to maximal effect and plateau and recovery periods were recorded. Skeletal muscle tone, presence of various reflexes, response to noxious stimuli, and heart rate were assessed.
Results: Results are given for protocols 10 mg kg(-1) 20°C; 20 mg kg(-1) 20°C; 10 mg kg(-1) 35°C and 20 mg kg(-1) 35°C, respectively: mean time (±SD) to maximal effect was 16±8, 19±6, 5±2 and 7±5 minutes; duration of the plateau phase was 13±12, 28±13, 8±5 and 8±5 minutes and recovery time was 76±20, 126±17, 28±9 and 41±20 minutes. Endotracheal intubation was successful in 80%, 100%, 0% and 30% of turtles, respectively. At 35°C, all animals retained nociceptive sensation in the front limbs, hind limbs and vent, whereas at 20°C a few turtles lost peripheral nociceptive sensation. Corneal and tap reflexes were retained in all trials. Mean heart rates were 30±2 and 66±4 beats minute(-1) at 20 and 35°C, respectively.
Conclusions and clinical relevance: Alfaxalone administered i.m. in red-eared sliders provided smooth, rapid induction and uneventful recovery. At 35°C either dosage provided only short (5-10 minutes) and light sedation. At 20°C, 10 mg kg(-1) provided sedation suitable for short non-invasive procedures. About 20 mg kg(-1) provided anaesthesia of approximately 20 minutes duration, appropriate for induction of inhalational anaesthesia or for brief surgical procedures with supplemental analgesia.
© 2012 The Authors. Veterinary Anaesthesia and Analgesia. © 2012 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesiologists.