Efficacy of intraoperative subanaesthetic dose of ketamine on post-operative analgesia for patients undergoing single level lumbar discectomy under general anesthesia: A placebo control randomized clinical study

60 patients of either gender, aged 18-65 years with American Society of Anesthesiologists (ASA) physical status I and II undergoing single level lumbar discectomy under general anesthesia. Exclusion criteria: high-risk coronary or vascular diseases, hepatic and renal dysfunction, history of psychosis, elevated intracranial pressure or traumatic brain injury, and uncontrolled hypertension.

Ketamine 0.3 mg/kg intravenous (IV) bolus followed by infusion at 4 μg/kg/min intraoperatively.

0.9% saline bolus dose of similar volume and infusion started at similar rate.

Post-operative pain relief measured by Numeric Rating Scale (NRS) score.patient reported