Multimodal anesthesia in rabbit (Oryctolagus cuniculus): preliminary observations

Anesthesia in rabbits presents significant challenges for veterinary practitioners due to the species' high susceptibility to stress, complex respiratory physiology, and a historically higher perioperative mortality rate compared to dogs and cats. This species is particularly susceptible to arrhythmias, which can result in the death of the subject, which can be attributed to its evolutionary status as a prey species. Indeed, handling stimulates the release of endogenous catecholamines, potentially triggering cardiac arrhythmias, especially in an anesthesiological setting [1,2]. The objective of this study is to evaluate the clinical efficacy and safety of a balanced anesthesia protocol. By combining different pharmacological agents, this approach aims to achieve good anesthesia, analgesia, and muscle relaxation while minimizing the dosages and side effects of individual drugs. The study was conducted on a sample of 5 rabbits undergoing a surgical procedure for odontogenic pathologies. To achieve sedation and preemptive analgesia, the following premedication protocol was performed: a combination of Midazolam (0.3 mg/kg) and Methadone (0.3 mg/kg) was administered via the intramuscular (IM) route. After 10 minutes, Dexmedetomidine (50 µg/kg) was injected IM. Induction was achieved with Propofol (2-5 mg/kg) injected intravenously (IV), while maintenance was obtained with Isoflurane (1.5-2%) vaporized in pure oxygen. Intraoperative analgesia was provided by an initial fentanyl bolus of 10–40 µg/kg administered over 5 minutes, followed by a constant rate infusion (CRI) of 5–10 µg/kg/h [3]. Locoregional anesthesia was also performed using 1% lidocaine diluted 1:10, up to a maximum volume of 2 ml/kg. Vital parameters, including heart rate (HR), respiratory rate (RR), oxygen saturation (SpO2), and end-tidal CO2 (EtCO₂), were monitored throughout the perioperative period. The protocol demonstrated good clinical stability. The combination of midazolam, methadone, and dexmedetomidine provided deep and rapid sedation, significantly reducing the dose of propofol required for induction. Recovery was generally smooth and free of significant agitation; notably, the majority of subjects resumed voluntary food intake within a few hours following surgery, despite the invasive nature of the odontogenic intervention. In conclusion, the data suggest that this protocol ensures robust hemodynamic stability and effective pain management. However, the study emphasizes that pharmacological success must be paired with advanced monitoring and meticulous perioperative care to further reduce mortality risks in lagomorphs.