Continuous rate infusion anaesthesia with dexmedetomidine-midazolam-ketamine-lignocaine in dogs

Six adult dogs of different breeds and ages, belonging to either sex, brought for various elective soft tissue and orthopaedic surgical procedures were anaesthetised using a combination of dexmedetomidine (5 µg/kg b.wt), butorphanol (0.2 mg/kg b.wt), midazolam (0.2 mg/kg b.wt) and ketamine (5 mg/kg b.wt), administered intramuscularly. Following induction, a loading dose of 2% lignocaine (2 mg/kg b.wt) was administered intravenously, and anaesthesia was maintained using a continuous rate infusion (CRI) of dexmedetomidine (2 µg/kg/hr), midazolam (3 µg/kg/min), lignocaine (50 µg/kg/min) and ketamine (40 µg/kg/min). The induction of anaesthesia was smooth, with no signs of anxiety and no laryngeal reflex, allowing easy intubation in 7.33±3.72 min. The maintenance of anaesthesia was also excellent. The heart rate, respiratory rate and rectal temperature decreased following induction. Initially, hypercapnia was observed with rise in blood pressure, which slowly returned to normal physiological range. The blood gases, electrolytes and haematological values did not show any significant variation; however, serum glucose significantly increased. Following cessation of the CRI, the animals rejected the endotracheal tube in 42±9.87 min, and the recovery was smooth. It was concluded that dexmedetomidine-butorphanol-midazolam-ketamine induced anaesthesia, followed by a CRI of dexmedetomidine-midazolam-lignocaine-ketamine can effectively maintain anaesthesia during various soft tissue and orthopedic surgeries in dogs.