Alfaxalone anaesthesia in Lemur catta following dexmedetomidine-butorphanol-midazolam sedation

Objective: To evaluate the clinical effects and the quality of sedation, induction, maintenance and recovery in Lemur catta, after dexmedetomidine-butorphanol-midazolam sedation and alfaxalone anaesthesia. Study design: Prospective, observational study Animals: Six male Lemur catta weighing 3.0 ± 0.6 kg undergoing surgical castration. Methods: Lemurs were sedated with intramuscular dexmedetomidine (0.015 mg kg-1), butorphanol (0.2 mg kg-1) and midazolam (0.2 mg kg-1). Anaesthesia was induced with intravenous alfaxalone 0.5 mg kg-1 over 60 seconds; further boluses were administered until tracheal intubation was feasible and the final dose was recorded. Alfaxalone continuous infusion was used to maintain anaesthesia. Atipamezole (0.15 mg kg-1) was administered during recovery. The quality of sedation, induction, intubation, maintenance and recovery was assessed using a scoring system. Physiological parameters were recorded during sedation, maintenance and recovery. Results: Sedation was achieved in 13.6 ± 5.6 minutes and no reactions were observed during handling or venepuncture. The mean dose of alfaxalone required for induction and maintenance was 2.09 ± 0.65 mg kg-1 and 0.08 ± 0.02 mg kg-1 minute-1, respectively. Quality of induction, intubation, and maintenance was good in almost all animals. Mild self-limiting muscle twitching was observed after alfaxalone administration in three animals. Cardiorespiratory function was stable in all animals but one. One lemur showed respiratory depression and required oxygen administration and manual ventilation. The mean maintenance time was 29.2 ± 7.4 minutes. The mean times from the end of alfaxalone administration to extubation, atipamezole administration and full recovery were: 15.3 ± 8, 22.2 ± 54.6 and 60.0 ± 8.0 minutes, respectively. Recovery was considered good in all animals. Conclusions and clinical relevance: The dexmedetomidine-butorphanol-midazolam combination used provided reliable sedation and adequate muscle relaxation in Lemur catta. Alfaxalone proved to be a useful drug for induction and maintenance of anaesthesia and might be considered an option for injectable anaesthesia in lemurs.