title: Minimum local analgesic concentration of ropivacaine for intra-operative caudal analgesia in pre-school and school age children.
abstract: We compared the minimum local analgesia concentration of ropivacaine for intra-operative caudal analgesia in pre-school and school age children. Fifty-one boys, undergoing hypospadius repair surgery, were stratified into pre-school or school age groups. After induction of anaesthesia, caudal block was performed with ropivacaine 1 ml.kg⁻¹ of the desired concentration. The first child in each group received ropivacaine 0.125%, and subsequent concentrations were determined by the analgesic response of the previous patient using Dixon's up-and-down method. Under general anaesthesia with 0.7 minimum alveolar concentration of sevoflurane, the minimum local analgesia concentration of ropivacaine for intra-operative caudal block was 34% greater in school age than in pre-school age boys (0.143% (95% CI 0.132-0.157%) vs 0.107% (95% CI 0.089-0.122%), respectively; p < 0.001). This study indicates that a higher concentration of ropivacaine is needed for school age than pre-school age children to provide intra-operative caudal analgesia when combined with general anaesthesia.
authors.affiliation: Department of Anaesthesiology, Plastic Surgery Hospital, Beijing, China.
authors.forename: X M
authors.initials: XM
authors.lastname: Deng
authors.forename: W J
authors.initials: WJ
authors.lastname: Xiao
authors.forename: G Z
authors.initials: GZ
authors.lastname: Tang
authors.forename: M P
authors.initials: MP
authors.lastname: Luo
authors.forename: K L
authors.initials: KL
authors.lastname: Xu
mesh_terms: D000367:Age Factors; D000577:Amides / Q000008:administration & dosage*; D000763:Anesthesia, Caudal / Q000379:methods*; D000769:Anesthesia, Inhalation / Q000379:methods; D018685:Anesthetics, Inhalation; D000779:Anesthetics, Local / Q000008:administration & dosage*; D002648:Child; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D006801:Humans; D007021:Hypospadias / Q000601:surgery; D007223:Infant; D008297:Male; D008738:Methyl Ethers; D016343:Monitoring, Intraoperative / Q000379:methods; D011446:Prospective Studies; D000077212:Ropivacaine; D000077149:Sevoflurane
chemical_list: D000577:Amides; D018685:Anesthetics, Inhalation; D000779:Anesthetics, Local; D008738:Methyl Ethers; D000077149:Sevoflurane; D000077212:Ropivacaine