Dexmedetomidine versus magnesium sulphate as adjuvants to ropivacaine in ilioinguinal-iliohypogastric nerve block for inguinal hernia repair: A randomised controlled trial.

Abstract

Background and aims: Ultrasound-guided ilioinguinal-iliohypogastric nerve block (II-IHNB) provides effective analgesia for inguinal hernia surgery; however, the duration of analgesia with local anaesthetic alone is limited. This study compared dexmedetomidine and magnesium sulphate as adjuvants to ropivacaine for II-IHNB.

Methods: In this randomised controlled trial, 120 patients were allocated into three groups (n = 40 each). Group A received 0.5% ropivacaine, group B received ropivacaine with magnesium sulphate (5 mg/kg), and group C received ropivacaine with dexmedetomidine (1 µg/kg). The primary outcome was time to first rescue analgesia. Secondary outcomes included visual analogue scale (VAS) scores, 24-hour opioid consumption, sedation, haemodynamic parameters, and adverse events.

Results: The time to first rescue analgesia was significantly longer in group C than in group A, with a median difference of 1080 min [95% confidence interval (CI): 923-1125 min; P < 0.001]. The total 24-hour opioid consumption was significantly lower in group C than in group A, with a median difference of - 10 morphine milligram equivalents (95% CI: -15 to - 5; P < 0.001). VAS scores at rest and movement were significantly lower in group C at multiple postoperative time points (P < 0.001). Sedation scores were higher in group C in the immediate postoperative period (P < 0.001), but no clinically significant respiratory depression occurred. Haemodynamic parameters and the incidence of adverse events remained comparable across groups (P > 0.05).

Conclusion: Dexmedetomidine is superior to magnesium sulphate as an adjuvant to ropivacaine in II-IHNB, providing prolonged analgesia, reduced opioid consumption, and stable haemodynamics with an acceptable sedation profile.