Comparison of Intrathecal Adjuvant Midazolam and Fentanyl with Hyperbaric Bupivacaine for Post-Operative Analgesia in Patient Undergoing Total Abdominal Hysterectomy

Abstract

Background: Spinal anaesthesia is preferred technique for conducting abdominal hysterectomy, but it is insufficient to provide post-operative analgesia adequately. The addition of local anaesthetic adjuvants increases subarachnoid block efficacy and prolongs postoperative analgesia. Due to its fast onset with a limited time of action with minimal cephalic spread, Fentanyl is preferred as an adjuvant in spinal anaesthesia. Adding Fentanyl to a low dose, Bupivacaine offers improved surgical anaesthesia and increased block reliability. Intrathecal midazolam raises threshold for pain by binding to the Benzodiazepine receptors in spinal cord.

Objectives: To compare theDuration of the postoperative analgesia (Time of 1st rescue Analgesic) between intrathecal administration of Midazolam (2.5mg) and fentanyl (25μg). To compare the duration and onset of sensory and motor block (modified bromage scale) , the effect on  haemodynamic parameter, 24hrs analgesic(paracetamol 15-20mg/kg) requirement(No of injection), Degree of sedation and side –effects (post-operative nausea and vomiting,pruritus,shivering ,urinary retention and any other).

Methodology:It is a comparative prospective study which will be conducted on 60 women posted for total abdominal hysterectomy. They will randomly divided into two groups having thirty patients in both groups. Group M will receive 2.5ml of 0.5% hyperbaric bupivacaine with 0.5ml (2.5mg) midazolam preservative free and Group F will receive 2.5ml 0.5% hyperbaric bupivacaine with 0.5ml (25µg) fentanyl intrathecally. The onset of sensory and motor block, duration of block, hemodynamic parameter, sedation score, total postoperative analgesia time and side effects if any will be recorded.

Expected result :We are trying to prove the hypothesis that addition of which adjuvant 2.5gm midazolam or 25 µg fentanyl given intrathecally to hyperbaric bupivacaine prolongs the duration post- operative analgesia more as compared to other.

Discussion: We will try to prove that addition of adjuvant fentanyl 25µg as compared to midazolam 2.5mg with 0.5% hyperbaric bupivacaine 12.5mg prolongs the post-operative analgesia when given intrathecally.