Comparative study of intrathecal fentanyl with bupivacaine and fentanyl midazolam with bupivacaine in spinal anaesthesia

Spinal anaesthesia is preferred for lower abdominal and lower limb surgeries. Bupivacaine is the most popular local anaesthetic for subarachnoid blockade because of less neurotoxicity. Intrathecal bupivacaine alone may be insufficient to provide prolonged post-operative analgesia, even with high sensory block. So, various adjuvants are used like ketamine, midazolam, clonidine, opioids, neostigmine etc. to prolong the effect of local anaesthetic. To compare the effect of intrathecal fentanyl and fentanyl-midazolam combination with hyperbaric bupivacaine for quality of anaesthesia and post-operative analgesia. Study was conducted on 60 patients aged 20-60 years and were randomly divided into two groups of 30 patients each. Group A received 0.5% bupivacaine heavy 3 ml (15mg) + fentanyl 0.5 ml (25µg) and Group B 0.5% bupivacaine heavy 2.8 ml (14mg) +fentanyl 0.5 ml (25 µg) + midazolam 0.2 ml (1mg). Total volume is 3.5 ml in both groups. They were assessed for quality of block, post-operative analgesia and perioperative complications. Data were compared using t- test(unpaired). The level of significance used was p<0.05. There was a significant difference in onset and duration of sensory and motor block, time to administer first rescue analgesia in group B. Addition of midazolam (1mg) to fentanyl with bupivacaine intrathecally gives better onset & duration of sensory & motor blockade and longer duration of post-operative analgesia.