Efficacy of Adding Midazolam to Bupivacaine (0.5%) on the Duration of Spinal Anesthesia in Unilateral Inguinal Hernia Surgery

Introduction: Inguinal hernia is the most common type of abdominal hernia which is 7 times more common in men than women. Surgical treatment is performed under general or local anesthesia (spinal or epidural). Neuraxial anesthesia has a greater advantage than general anesthesia. Today, spinal block anesthetics with local drug anesthetics along with adjuvant drugs is widely used for surgery. Midazolam is one of these adjuvants whose spinal injection, in addition to its appropriate analgesic effect, enhances the effect of local anesthetics. Aim: The aim of this study was to determine the effect of intrathecal midazolam (1 mg) to bupivacaine (0.5%) on the quality and timing of sensory block, motor block and hemodynamic changes during of inguinal herniation surgery. Materials and Methods: 64 patients with ASAI / II criteria (30-70 years old) were randomly divided into two groups of 32 patients under spinal anesthesia for inguinal herniation surgery. The anesthesiologist and the patient did not know the status of the studied drugs. Group 1 received 0.5 ml of bupivacaine 0.5% + 0.2 ml of normal saline and group 2 received 3 ml of bupivacaine 0.5% + 0.2 ml of midazolam (1 mg). The return time of sensory block and the return time of motor block, the time of the first request for analgesics, the degree of satisfaction and the hemodynamic status were compared between these group. Results: The return time of sensory block in group 1 was 124.81 ± 16.15 minutes and in group 2 was 193.18± 34.53 minutes, which was statistically significant and in group 2 the return time of sensory block was longer (001 ≤. ˂P). reaction block return time: in group 2: (140.43 ± 27.46) minutes, group: 1 (107.78 ± 13.82) minutes were shorter and statistically significant (P≤ .001). The time of the first analgesic request by patients in group 1 was 157.87 ±16.32 minutes and in group 2, 264.59 ± 50.17 minutes, which was statistically significant (P ≤ .001). Satisfaction index and hemodynamic changes were not significant between groups (P ˃ 0.05). Conclusion: Addition of 1 mg of midazolam in spinal anesthesia with bupivacaine 0.5% increased of the duration of analgesia and the time of first request for analgesia without changing the hemodynamic status in patients with inguinal herniation surgery.