The minimum alveolar concentration of sevoflurane in ring-tailed lemurs (Lemur catta) and aye-ayes (Daubentonia madagascariensis)

Gonadectomy in Raccoons: Anesthetic and Cardiorespiratory Effects of Two Ketamine-Based Pre-Anesthetic Protocols before Sevoflurane-Sufentanil

Nineteen raccoons were enrolled in this study. The aim was to evaluate and compare the quality of anesthesia and the cardiorespiratory effects following treatment with a ketamine-based combination with either dexmedetomidine (KD group) or midazolam (KM group) in raccoons undergoing ovariohysterectomy/orchiectomy. General anesthesia was maintained with sevoflurane in oxygen and sufentanil infusion. The time required to approach the animals was similar among groups resulting in a median of 5 min after IM injection. Animals in group KD were scored with greater myorelaxation (p < 0.01) and easier intubation (p < 0.05). Moreover 70% of them did not require other drugs for tracheal intubation unlike animals in group KM, which required propofol in 100% of cases. After intubation and connection to the breathing circuit, physiological parameters were monitored continuously and recorded every 5 min. Sevoflurane requirements were lower in group KD than KM (p = 0.005). Blood pressure was maintained within physiological ranges in both groups but with higher values in group KM (p < 0.05). Mild respiratory depression occurred during surgery and animals in group KM showed greater respiratory acidosis (p < 0.05). Recovery was smooth and uneventful in all animals. Both anesthetic protocols can be recommended for safe anesthesia in wild raccoons.

Combination of intramuscular alfaxalone, butorphanol, and midazolam as a novel immobilization protocol in 3 ring-tailed lemurs (Lemur catta)

Background

There is very little data on the optimal anaesthetic management of ring-tailed lemurs, and the available information is mostly based on extrapolation from other species. In addition, a thorough pre-anaesthetic assessment of lemurs might not be possible without prior chemical immobilization, making a safe immobilization protocol essential.

Case presentation

Three ring-tailed lemurs (Lemur catta) were immobilized using a combination of intramuscular alfaxalone (5 mg/kg), butorphanol (0.2 mg/kg), and midazolam (0.2 mg/kg), at the University College Dublin Veterinary Hospital. One lemur was anaesthetised once, two lemurs twice, amounting to five anaesthetic events. Conversion to general anaesthesia was warranted in all five occasions, and anaesthesia was maintained with either sevoflurane in oxygen or alfaxalone infusion. The immobilization protocol provided an adequate duration of deep sedation for diagnostic procedures and in some occasions allowed the intubation of the trachea. Analgesia was also provided for minor procedures. No major complications were noted with the protocol used.

Conclusions

The combination of intramuscular alfaxalone, butorphanol and midazolam provided a clinically useful sedation/immobilization in ring-tailed lemurs with only minor complications such as mild hypothermia, hypotension, hypoventilation and bradycardia. This protocol could be considered in ring-tailed lemurs that need to be immobilized for minor procedures, or as a pre-anaesthetic premedication, especially if a full pre-anaesthetic clinical exam is not possible.

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

OBJECTIVE

To evaluate the clinical effects and 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 L. 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 final dose 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 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 ± 8.0, 22.2 ± 4.6 and 60.0 ± 8.4 minutes, respectively. Recovery was considered good in all animals.

CONCLUSIONS AND CLINICAL RELEVANCE

Dexmedetomidine-butorphanol-midazolam combination provided reliable sedation and adequate muscle relaxation in L. 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.