Dexmedetomidine versus Magnesium as Adjuvants to Bupivacaine-Induced Caudal Block in Children: A Randomized, Double-Blinded, Placebo-Controlled, Trial

BACKGROUND: Caudal block remains fundamental in pediatric anaesthetic practice. It is very useful in a wide range of surgical procedures and has proved to have a remarkable safety record, But one of the major limitations of the single-injection technique is the relatively short duration of postoperative analgesia. Prolongation of caudal analgesia using single-shot technique has been achieved by the addition of various adjuvant. AIM: This work aims to compare magnesium and dexmedetomidine as adjuvants to bupivacaine-induced caudal block in children undergoing lower limb orthopaedic surgery. STUDY DESIGN: Randomized, double-blind trial. SETTINGS: Pediatric or of a tertiary care centre. METHODS: A double-blinded, randomised controlled trial included 36 children, aged between 1 and 7 years, scheduled for lower limb orthopaedic surgery. Patients received general anaesthesia in addition to the caudal block. Patients were divided into three groups: Dexmedetomidine group (n = 12): received 0.5 mL/Kg bupivacaine + 2 mcg/Kg dexmedetomidine, Magnesium group (n = 12): received 0.5 mL/Kg bupivacaine + 50 mg magnesium, and control group (n = 12): received 0.5 mL/Kg bupivacaine + normal saline. Patients were compared according to the duration of analgesia, pain scores, sedation scores, mean arterial pressure, and heart rate. RESULTS: Both magnesium group and dexmedetomidine group showed better analgesic profile (duration of analgesia and pain scores) compared to the control group without significant difference between the two former groups. Dexmedetomidine group showed higher sedation score, lower mean arterial pressure and lower heart rate compared to other groups. CONCLUSIONS: Both magnesium (50 mg) and dexmedetomidine (2 mcg/Kg) improved the analgesic profile of bupivacaine-induced caudal block in children. Dexmedetomidine administration was accompanied with higher sedation score and negative hemodynamic profile.