Effect of adding midazolam to bupivacaine during rectus sheath block: a randomised controlled trial

BACKGROUND: Various adjuvants have been tried to improve quality and increase duration of local anaesthetics during various nerve blocks. We aimed to evaluate the effect of adding midazolam to bupivacaine on rectus sheath (RS) block in patients undergoing umbilical or epigastric hernia repair. METHODS: In all, 60 adult patients were divided into two equal groups, each group included 30 patients. Group I received 20 ml of bupivacaine hydrochloride 0.25% + midazolam 50 μg/kg in 2 ml saline 0.9% (Midazolam group, n = 30), whereas Group II received 20 ml of bupivacaine hydrochloride 0.25% + 2 ml saline (Control group, n = 30) for RS block on each side. The primary outcome was post-operative 48 h morphine consumption, whereas secondary outcomes included analgesia duration, post-operative pain, as evaluated by visual analogue scale (VAS) for pain scoring at 1, 2, 6, 12, 24 and 48 h post-operatively, reported post-operative nausea and or vomiting (PONV), somnolence or any adverse drug reactions. RESULTS: The current study showed that addition of midazolam to bupivacaine for RS blockade provided good analgesia as evidenced by a statistically significant less morphine consumption in the post-operative 48 h [11.2 (5.3-18.3) vs. 25.9 (15.2-31.0) mg, P = 0.002], longer duration of analgesia, lower VAS during post-operative 48 h, lower incidence of PONV, somnolence and pruritus. CONCLUSION: Midazolam addition to bupivacaine for RS blockade provided adjuvant analgesia as supported by less morphine consumption, longer duration of analgesia, and lower VAS score.