Caudal bupivacaine supplemented with morphine or clonidine, or supplemented with morphine plus clonidine in children undergoing infra-umbilical urological and genital procedures: a prospective, randomized and double-blind study

Abstract

We aimed to evaluate postoperative analgesia of morphine, or clonidine, or morphine plus clonidine, added to caudal bupivacaine in children undergoing infra-umbilical urological and genital procedures. Eighty patients aged 1-10years were prospectively enrolled. After the induction of general anesthesia, the patients were randomized to four caudal anesthesia groups: Group B (1.0mL/kg of bupivacaine 0.166% with epinephrine 1:600,000); Group BM (1.0mL/kg of bupivacaine 0.166% with epinephrine 1:600,000 plus morphine 20μg/kg); Group BC (bupivacaine 0.166% with epinephrine 1:600,000 plus clonidine 1.0μg/kg), and Group BMC (bupivacaine 0.166% with epinephrine 1:600,000 plus morphine 20μg/kg and clonidine 1.0μg/kg). Duration of surgery, emergence time, postoperative pain score measured by the face, legs, activity, cry, consolability (FLACC) scale, postoperative analgesia time, and overall use of rescue analgesics were recorded. The FLACC pain score (6, 12, and 24h after the surgery) and the number of patients requiring analgesics during the first 24h of the postoperative period were higher in Groups B and BC than in Groups BM and BMC (p<0.05). The incidence of pruritus and urinary retention was comparable between the groups (p>0.05). However, the incidence of postoperative nausea and vomiting (PONV) was higher in Groups BM (35%) and BMC (25%) than in Groups B (5%) and BC (5%) (p<0.05). To conclude, we showed that 20μg/kg of morphine added to caudal bupivacaine 0.166% plus epinephrine 1:600,000 decreased the use of analgesics in the postoperative period, although it was associated with an increased incidence of PONV. However, the addition of clonidine (1.0μg/kg) to caudal bupivacaine provided no additional clinical benefit over bupivacaine alone.