Comparative study of three anaesthetic protocols (dexmedetomidine/ketamine, dexmedetomidine/midazolam, midazolam/ketamine) in dwarf rabbits undergoing elective orchiectomy

Abstract

This prospective clinical study aimed to compare three different anaesthetic protocols in dwarf rabbits and analyse the effects of these pharmacological combinations from premedication to complete recovery. Twenty-one pet rabbits were randomly allocated in study groups – MKM (7 rabbits): midazolam (0.2 mg/kg), ketamine (20 mg/kg), and methadone (0.3 mg/kg) were administered subcutaneously (SC); DKM (7 rabbits): received dexmedetomidine (25 µg/kg), ketamine (20 mg/kg), and methadone (0.3 mg/kg) SC; MDM (7 rabbits): received midazolam (0.2 mg/kg), dexmedetomidine (25 µg/kg), and methadone (0.3 mg/kg) SC. Ten minutes before premedication and every 5 min for 20 min (T5, T10, T15, and T20, respectively), heart rate, respiratory rate, and sedation score (SS) were recorded. Cases of ataxia/incoordination were also reported. After induction of general anaesthesia, main cardiovascular and respiratory parameters were monitored during skin incision, testicular traction, and suture placement. At the end of the procedure, extubation time, recovery of sternal recumbency and quadrupedal stance, and quality of recovery (QR) were recorded. The DKM group showed higher SS at T10 than the other two groups; however, 4 out of 7 subjects manifested ataxia and incoordination, compared to the MDM, in which no episodes occurred. Time to extubation in the MKM was longer (6.8 ± 3.5 min) compared to the MDM (2.6 ± 2.07 min); moreover, QR was worse in the DKM and MKM groups compared to MDM. The combination of dexmedetomidine/ketamine provides better sedation; however, it frequently induces ataxia/incoordination. The further addition of midazolam could promote muscle relaxation and tranquillisation, reducing handling stress in pet rabbits.