RESUMEN
STUDY OBJECTIVES: The aim of this study was to compare the effects of caudal and intravenous (IV) dexmedetomidine (1 µg/kg) on postoperative analgesia after caudal bupivacaine in pediatric patients undergoing lower abdominal and perineal surgeries. DESIGN: A randomized controlled double-blind study. SETTING: University-affiliated teaching hospital. PATIENTS: Seventy-five American Society of Anesthesiologists I children, aged 1 to 6 years. INTERVENTION: Patients were randomly allocated to 3 groups. All patients received 1 mL/kg caudal 0.25% bupivacaine. In addition, those in group B (n=25) received 10-mL IV saline, those in group B-Dcau (n=25) received 1 µg/kg caudal dexmedetomidine and 10-mL IV saline, and those in group B-DIV (n=25) received 1 µg/kg IV dexmedetomidine in 10-mL saline. MEASUREMENTS: Intraoperative mean blood pressure, heart rate, peripheral oxygen saturation, end-tidal sevoflurane, and bispectral index as well as postoperative pain and behavior scores and time to first analgesia were assessed. MAIN RESULTS: Group B-Dcau had a significantly longer time to first rescue analgesia than groups B-DIV and B, with mean (SD) values of 14.4 (7.5), 9.18 (2.7), and 6.6 (2.5) hours, respectively (P<.05). Fewer patients in group B-Dcau (n=16) required rescue analgesia during the first 24 hours postoperatively compared to group B (n=24) and group B-DIV (n=20) (P<.05). Groups B-Dcau and B-DIV had lower pain and behavior scores than Group B. Eight patients Group B had agitation compared to 2 in Group B-DIV and 0 in Group B-Dcau. Four patients in Group B-DIV developed bradycardia and hypotension during surgery. CONCLUSIONS: Compared to IV administration, caudal administration of dexmedetomidine during caudal bupivacaine anesthesia provided prolonged postoperative analgesia and a greater analgesic sparing effect without significant side effects. This suggests a greater role of neuraxial compared to that of peripheral α-2 adrenoceptors in pain processing.
