Effects of addition of fentanyl and midazolam to local anaesthetic in lumbar epidural anaesthesia for infraumbilical surgeries

Introduction: Compared to general anaesthesia, regional anaesthetic techniques are more preferred in lower limb and lower abdominal surgeries as they have many advantages. Fentanyl a short acting opioid agonist, acts at µ receptor which is hundred times more potent than morphine. Fentanyl has many advantages compared to morphine because of its rapid onset of action and superior intra operative analgesia. Midazolam has an analgesic action by its action on the benzodiazepine GABA A receptor. Aim: The primary aim of the study was to compare the effect of two adjuncts to 0.5% bupivacaine through epidural anaesthesia. The study was directed towards the patients posted for infra umbilical surgeries. Materials and Methods: This study is conducted at Rajah Muthiah Medical College Hospital from august 2015- march 2016. Fifty patients posted for elective infra umbilical surgeries were divided into groups of 25 each. Group F received 18ml of 0.5% bupivacaine with 2 ml containing 100µg fentanyl and group M received 18ml of 0.5% bupivacaine with 2 ml of 2mg midazolam. Results: Both the groups maintained haemodynamic stability. Onset of sensory block was faster in group F (6.40 min) compared to group M (10.00min) which was statistically significant. The two segment regression time was found to be 150.8 min in group F compared to 147 min in group M. The mean duration of postoperative analgesia was significantly prolonged in group F (293.20min) when compared to group M (224.60min) with significant P value (0.05) Conclusion: Patients of fentanyl group exhibited prolonged duration of analgesia in comparison to midazolam group. Therefore fentanyl is more suited to midazolam in providing prolonged postoperative analgesia. Epidural fentanyl also produced faster onset of sensory blockade. There were no significant haemodynamic changes in both the groups. The occurance of nausea and vomiting was managed with a single dose of antiemetic.