Bupivacaine (0.5%) Versus (0.5%) Bupivacaine with Ketamine (50 mg) for Subarachnoid Block in Lower Abdominal Surgeries: A Randomised Comparative Study

Introduction: Spinal anaesthesia is the preferred technique for most of the lower abdominal surgeries nowadays. Currently, Bupivacaine is the most commonly used drug in spinal anaesthesia. A number of adjuvants have been used to improve postoperative analgesia, along with the bupivacaine. Intrathecal ketamine, which is a N-Methyl D-Aspartate (NMDA) blocker prolongs the duration of postoperative analgesia due to inhibition of dorsal horn. Aim: To assess the duration of postoperative analgesia between two groups i.e., bupivacaine alone and bupivacaine with ketamine and also to assess the intraoperative and postoperative haemodynamic stability, onset and duration of sensory as well as motor block, side-effects of injection ketamine when given intrathecally as an adjuvant with injection bupivacaine. Materials and Methods: A prospective, randomised study was conducted in 60 patients with American society of Anaesthesiologist (ASA) Class I and II aged between 20-60 years posted for elective lower abdominal surgeries under subarachnoid block and were randomly selected and divided into two groups of 30 each. Bupivacaine Group B received intrathecal bupivacaine 12.5 mg (2.5 mL)+1.0 mL normal saline (total volume of 3.5 mL) whereas, ketamine Group BK received intrathecal bupivacaine 12.5 mg (2.5 mL)+1 mL (50 mg) Ketamine (total volume of 3.5 mL). Statistical analysis was done by using descriptive and inferential statistics using chi-square test and Student's t-test. Results: The onset of sensory block was faster in group BK than compared to group B. Duration of sensory block and the time for 1st pain medication was significantly prolonged in Group BK. Haemodynamic parameters were comparatively more stable in Group BK than Group B. Conclusion: Ketamine, when added to bupivacaine intrathecally, decreased onset and prolonged the duration of sensory block. It also prolonged the postoperative analgesia with better haemodynamic stability than bupivacaine alone.