Evaluation of midazolam-ketamine-xylazine or propofol-ketamine combination for maintenance of anaesthesia by constant rate infusion (CRI) in dogs

The study was conducted to evaluate the constant rate infusion (CRI) anesthesia using two protocols on 20 healthy bitches brought for oophorectomy by conventional and laparoscopic methods. The animals were divided into 2 groups (A and B) based on the technique chosen for oophorectomy and were further subdivided into 2 subgroup each containing 5 animals. All the animals of four sub-groups received glycopyrrolate (0.01 mg/kg b.wt, i.m.) followed 10 min later by xylazine (0.5 mg/kg b.wt, i.m.) as preanaesthetic medication. After 10 min of the administration of preanaesthetics, anaesthesia was induced by administering a mixture of midazolam (0.2 mg/kg b.wt, i.v.) and ketamine (5.0 mg/kg b.wt, i.v.). After 5 min of anaesthetic induction, the maintenance of anaesthesia was started with midazolam (0.4 mg/kg/hr)-ketamine (20 mg/kg/hr)-xylazine (1.0 mg/kg/hr) in animals of sub groups A₁ and B_1, while propofol (3.6 mg/kg/hr)-ketamine (5.4 mg/kg/hr) in the animals of subgroups A₂ and B₂ as CRI using an infusion pump. The anaesthetic protocols were evaluated for clinico-physiological parameters such as sedation quality, muscle relaxation, palpebral reflex, pedal reflex, response to intubation, sternal recumbency time (SRT), complete recovery time (CRT), heart rate, respiratory rate and rectal temperature. Propofol-ketamine combination was found more suitable in comparison to midazolamketamine-xylazine combination for maintenance of anaesthesia by CRI for oophorectomy by conventional as well as laparoscopic methods in bitches.