title: Pharmacokinetics of 0.2% ropivacaine and 0.2% bupivacaine following caudal blocks in children.
abstract: BACKGROUND
  Ropivacaine is the first S-enantiomer aminoamide local anaesthetic in clinical use, and has been found to be less toxic than bupivacaine. Caudal ropivacine has been shown to cause less motor blockade and longer duration of analgesia in the postoperative period than bupivacaine in children. Plasma levels of ropivacaine and bupivacaine have not been previously compared in children. This study was undertaken to compare the total venous plasma concentrations of similar doses of ropivacaine and bupivacaine following caudal administration.
  
  
  METHODS
  Blood samples were obtained to determine the total venous plasma levels of the used local anaesthetic in 30 children, aged 2.3-8.7 years, ASA I, given 1 ml x kg of either 0.2% ropivacaine or 0.2% bupivacaine in a prospective, randomised manner.
  
  
  RESULTS
  There were no differences in the individual peak plasma concentrations achieved. Time to the measured peak plasma concentration was significantly shorter in the bupivacaine group. The plasma concentrations of bupivacaine were significantly lower than for ropivacaine at 60, 90 and 120 min after the block.
  
  
  CONCLUSIONS
  Absorption and tissue distribution of ropivacaine is slower than for bupivacaine following caudal administration in children.
authors.affiliation: Department of Anaesthesiology University of Oulu, Finland. tak@cc.oulu.fi
authors.forename: T I
authors.initials: TI
authors.lastname: Ala-Kokko
authors.forename: A
authors.initials: A
authors.lastname: Partanen
authors.forename: J
authors.initials: J
authors.lastname: Karinen
authors.forename: K
authors.initials: K
authors.lastname: Kiviluoma
authors.forename: S
authors.initials: S
authors.lastname: Alahuhta
mesh_terms: D000577:Amides / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D000775:Anesthesia, Spinal; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D002045:Bupivacaine / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009407:Nerve Block; D011446:Prospective Studies; D000077212:Ropivacaine
chemical_list: D000577:Amides; D000779:Anesthetics, Local; D000077212:Ropivacaine; D002045:Bupivacaine