Dexmedetomidine decreases the required amount of bupivacaine for ultrasound-guided transversus abdominis plane block in pediatrics patients: a randomized study.

BACKGROUND: The effect of dexmedetomidine on the potency of bupivacaine for transversus abdominis plane (TAP) block in pediatric patients has not been investigated.

STUDY OBJECTIVE: The primary objective of this study was to assess the effectiveness of dexmedetomidine to decrease the concentration of bupivacaine needed for analgesia for ultrasound-guided TAP block in a pediatric patient undergoing hernia repair or hydrocelectomy.

DESIGN: This is a randomized, double-blind, up-down, dose-finding study.

SETTING: Operating room.

PATIENTS: Sixty American Society of Anesthesiologists I and II patients aged 1-4 years scheduled for elective unilateral herniorrhaphy or hydrocelectomy.

INTERVENTIONS: Patients were randomly assigned to 1 of the 2 groups: group B (0.125% bupivacaine, 1mL/kg) TAP block or group BD (0.125% bupivacaine plus 2μg/kg dexmedetomidine, 1mL/kg) TAP block.

MEASUREMENTS: The response of each child was observed for 60 seconds after skin incision and evaluated as 'unsuccessful' when skin incision caused a change in hemodynamic parameters (heart rate and mean blood pressure) 20% more than the preincision values. If the response was determined to be unsuccessful, the concentration of bupivacaine administrated to the next patient was increased by 0.02%. If it was successful, the concentration of bupivacaine administrated to the next patient was decreased by 0.02%.

RESULTS: The minimum local anesthetic concentration of bupivacaine was 0.0839% (0.0137) in the B group and 0.0550% (0.0169) in the BD group. The difference was statistically significant (t=7.165, P=.0001). The total postoperative analgesic dosage of morphine was significantly higher in the B group (0.17±0.04 mg/kg) than the BD group (0.11±0.02 mg/kg, P=.001).

CONCLUSIONS: The addition of 2μg/kg of dexmedetomidine reduced the minimum local anesthetic concentration of bupivacaine used for a TAP block and improved postoperative analgesia in children undergoing surgery for inguinal hernia repair or hydrocelectomy.