Dose Response Characteristics of Intrathecal Hyperbaric Bupivacaine (0.5%) by Using Sequential Combined Spinal Epidural Anaesthesia for Orthopaedic Surgeries of Lower Limb

Combined spinal epidural anaesthesia (CSEA) technique provides advantages of both subarachnoid block and epidural block. In the present study primary objective was to compare sensory level and degree of motor block achieved with initial intrathecal dose at the end of 10 minutes with peak sensory level achieved with initial intrathecal dose of 7.5 mg and 10 mg hyperbaric 0.5 % bupivacaine respectively whereas secondary objective was to compare adverse events in orthopaedic surgery patients. Sixty patients were included in this randomized controlled study conducted between April 2016 and December 2016. Group A and Group B patients received sequential CSEA with 7.5 mg and 10 mg of 0.5 % hyperbaric bupivacaine respectively intrathecally. Primary outcome measures were mean time required to achieve T 10 levels, mean onset on motor block, mean time to give top up , total number of top ups required whereas secondary outcome measure were adverse events. Comparison of quantitative and qualitative variables between groups was done using unpaired student’s “t” test and chi-square test respectively. Sequential CSEA with Group B showed rapid onset, more profound and long lasting block with less number of epidural top ups but more number of adverse events of hypotension. While sequential CSEA with Group A showed requirement of frequent number of top ups to maintain desired anaesthesia but more stability in haemodynamic with less adverse events of hypotension and bradycardia. Sequential CSEA with low dose 7.5 mg bupivacaine is better choice than 10 mg bupivacaine as initial intrathecal dose by using CSEA.