Ropivacaine-clonidine combination for caudal blockade in children

Background: Adding clonidine to weak ropivacaine solutions (<0.2%) could po tentially enhance analgesia as well as further reduce the risk for unwanted motor blockade. The aim of the present study was to compare the postoperat ive pain-relieving quality of a ropivacaine 0.1%-clonidine mixture to that of plain ropivacaine 0.2% following caudal administration in children. Methods: In a prospective, observer-blinded fashion, 40 ASA 1 paediatric pa tients undergoing subumbilical surgery were randomly allocated to receive a caudal injection of either plain ropivacaine 0.2% (1 ml/kg) (R0.2) or a mi xture of ropivacaine 0.1% with clonidine 2 mu g/kg (1 ml/kg) (R0.1C). Objec tive pain scale score and need for supplemental analgesia were used to eval uate analgesia during the first 24 h postoperatively. Residual postoperativ e sedation was also assessed. Results: A significantly higher number of patients in the R0.1C group (18/2 0) could be managed without supplemental analgesia during the first 24 h po stoperatively compared to the R0.2 group (11/20) (P=0.034). Both the degree and the duration of postoperative sedation was similar in both groups. No signs of postoperative motor blockade were observed. Conclusions: The combination of clonidine (2 mu g/kg) and ropivacaine 0.1% is associated with an improved quality of postoperative analgesia compared to plain 0.2% ropivacaine. The improved analgesic duality of the clonidine- ropivacaine mixture is achieved without causing any significant degree of p ostoperative sedation. (C) Acta Anaesthesiologica Scandinavica 44 (2000).