Semester of Graduation
Master of Science (MS)
Veterinary Clinical Sciences
Domestic rabbits have a high risk of anesthesia-related mortality compared to other companion animals. Factors that may contribute to increased mortality include drug-induced cardiopulmonary effects (Grint & Murison 2008; Navarrete-Calvo et al. 2013), difficulty performing intubation (Aeschbacher 1995; Flecknell 2016; Wenger et al. 2017) or damage to laryngeal and tracheal tissues following orotracheal intubation (Grint et al. 2006; Phaneuf et al. 2006; Engbers et al. 2017).
Alfaxalone is a neuroactive steroid that produces induction of anesthesia and cardiorespiratory depression in a dose-dependent manner when injected intravenously. The ability to induce anesthesia via an intramuscular (IM) route has several advantages in the rabbit including possible reduction in cardiopulmonary adverse effects and reduced stress of handling for intravenous catheter placement. The dose of alfaxalone needed to produce an adequate plane of anesthesia to allow intubation has not been evaluated in rabbits. Therefore, one objective of this research was to determine the optimal dose of IM alfaxalone in combination with dexmedetomidine and hydromorphone that would allow endoscopic orotracheal intubation of rabbits. For this chapter, three different doses of alfaxalone (2, 5, and 7 mg kg-1) IM were tested in combination with 0.1 mg kg-1 hydromorphone and 0.005 mg kg-1 dexmedetomidine. Following administration of the drug combination containing 7 mg kg-1 alfaxalone, intubation was successful in 80% of rabbits.
The consequences of repeated intubation attempts using different intubation techniques on respiratory tissue damage and the potential increase in mortality are largely unknown and have has not been extensively studied. Therefore, another objective of this research was to compare respiratory tissue damage caused by blind versus endoscopic-guided intubation of rabbits, and to correlate the number of intubation attempts with the degree of respiratory tissue damage. For this chapter, rabbits were administered 7 mg kg-1 alfaxalone in combination with 0.1 mg kg-1 hydromorphone and 0.005 mg kg-1 dexmedetomidine IM. Intubation was attempted using either the blind or endoscopic-guided technique. The results demonstrated that blind intubation was associated with a higher number of intubation attempts; however, no difference in the degree of tissue damage was observed between the two techniques.
Reabel, Stephanie, "Anesthetic Combination of Alfaxalone, Dexmedetomidine and Hydromorphone for Comparison of Endoscopy-Guided Intubation and Blind Orotracheal Intubation in Domestic Rabbits (Oryctolagus cuniculus)" (2021). LSU Master's Theses. 5301.