Evaluation of immobilisation using a fixed-dose combination of butorphanol, azaperone, and medetomidine, along with a low dose of ketamine, in chacma baboons (Papio ursinus).

Abstract

Background: Current literature most commonly describes the use of the dissociative drug ketamine for the immobilisation of baboons, either on its own or in combination with other drugs such as α-2 agonists or benzodiazepines. Currently, no reversal is available for ketamine, leading to prolonged and often rough recoveries of the animals, especially if high doses of ketamine are used.

Objective: In this study, the fixed-dose combination of butorphanol, azaperone and medetomidine (BAM) with a low dose of ketamine (K-BAM) was evaluated for immobilisation and recovery parameters of chacma baboons.

Methods: Fifteen baboons were immobilised and monitored. Actual doses administered: BAM 0.01 ± 0.005 ml/kg (butorphanol 0.31 ± 0.15 mg/kg, azaperone 0.12 ± 0.06 mg/kg, medetomidine 0.12 ± 0.06 mg/kg) and ketamine 2.04 ± 0.22 mg/kg. During immobilisation, heart rate (HR), respiration rate (RR), peripheral oxygen saturation (SpO₂), end-tidal carbon dioxide (EtCO₂), noninvasive blood pressure (BP) and blood gases were evaluated.

Results: Inductions were reached in 3.46 ± 1.36 minutes. Overall, severe hypoxaemia (SpO₂: 62 ± 13%; PaO₂: 37 ± 10 mmHg) was observed in all baboons as well as elevated EtCO₂ (63 ± 9 mmHg) and PaCO₂ (63 ± 9 mmHg) values. Other measured parameters stayed within normal ranges. Recoveries were fully reached at 4.8 ± 2.8 minutes after intramuscular injection of the reversal naltrexone and atipamezole.

Conclusion: BAM with a low dose of ketamine produced short-term immobilisation, allowing for minor veterinary procedures. The evere hypoxaemia observed in all animals, however, raises serious concerns regarding the safety of this protocol.