Addition of dexmedetomidine to bupivacaine in transversus abdominis plane block potentiates post-operative pain relief among abdominal hysterectomy patients: A prospective randomized controlled trial

Dexmedetomidine is an alpha 2 adrenergic agonist, prolongs analgesia when used in neuraxial and peripheral nerve blocks. We studied the effect of addition of dexmedetomidine to bupivacaine to perform transversus abdominis plane (TAP) block. A total of 50 patients scheduled for abdominal hysterectomy were divided into two equal groups in a randomized double-blinded way. Group B patients (n = 25) received TAP block with 20 ml of 0.25% bupivacaine and 2 ml of normal saline while Group BD (n = 25) received 0.5 mcg/kg (2 ml) of dexmedetomidine and 20 ml of 0.25% bupivacaine bilaterally. Time for first analgesic administration, totally used doses of morphine, pain scores, hemodynamic data and side-effects were recorded. Demographic and operative characteristics were comparable between the two groups. The time for the first analgesic dose was longer in Group BD than Group B (470 vs. 280 min, P < 0.001) and the total doses of used morphine were less among Group BD patients in comparison to those in Group B (19 vs. 29 mg/24 h, P < 0.001). Visual analog scores were significantly lower in Group BD in the first 8 h post-operatively when compared with Group B, both at rest and on coughing (P < 0.001). In Group BD, lower heart rate was noticed 60 min from the induction time and continued for the first 4 h post-operatively (P < 0.001). The addition of dexmedetomidine to bupivacaine in TAP block achieves better local anesthesia and provides better pain control post-operatively without any major side-effects.