Use of ketamine, xylazine, and diazepam anesthesia with retrobulbar block for phacoemulsification in dogs

Objective  The study was undertaken to evaluate the use of ketamine, xylazine, and diazepam along with a local retrobulbar nerve block for routine phacoemulsification in the dog.
Animals  Ten clinically healthy mixed-breed dogs of either sex, weighing between 10 and 15 kg.
Procedures  Ten mixed-breed dogs were selected for unilateral cataract removal by phacoemulsification. Standard preoperative preparations for cataract surgery were followed. Pre-anesthetic medication consisted of atropine sulfate (0.02 mg/kg, SC). Anesthesia was induced by xylazine HCl (1.0 mg/kg, IM) followed by ketamine (5.0 mg/kg, IM). Anesthesia was maintained subsequently with IV ketamine and diazepam to effect and depth of anesthesia was assessed clinically by pedal reflex and jaw reflex. After induction of anesthesia, a retrobulbar nerve block was performed using 2 mL of 2% lignocaine. Eye position was graded after retrobulbar block and IOP was examined preoperative, post-anesthetic, 6 h postoperative and 24 h after surgery. Phacoemulsification was performed using the phaco-chop technique and an intraocular lens was placed. Anesthetic recovery and postoperative recovery following surgery was recorded.
Result  The exposure of the globe in all the dogs was adequate; the desired central fixation of the eye was obtained and surgery could be performed uneventfully. The mean IOP recorded after induction of anesthesia was 15.75 ± 0.82, which was not significantly ( P  > 0.01) different from pre-anesthetic values (14.85 ± 0.85).
Conclusion  Phacoemulsification was successfully performed with this anesthetic regimen without encountering major intraoperative or anesthetic complications.