title: Brief report: perioperative analgesic efficacy and plasma concentrations of S+ -ketamine in continuous epidural infusion during thoracic surgery.
abstract: BACKGROUND
  In our study, we evaluated the analgesic effect and plasma level time course of subanesthetic doses of intraoperative S(+)-ketamine administered by continuous epidural infusion for postthoracotomic pain.
  
  
  METHODS
  A study population of 140 patients undergoing thoracic surgery was randomly assigned to either S(+)-ketamine or ropivacaine by continuous epidural infusion. The outcome measures were as follows: (a) intraoperative fentanyl requirements; (b) postoperative pain intensity; and (c) postoperative rescue analgesics.
  
  
  RESULTS
  Intraoperative fentanyl consumption was significantly lower (median of difference: -58.6 μg; 95% confidence interval [CI], -97.2 to -19.6 μg; P = 0.0032) in patients in the ketamine group than those in the ropivacaine group. Postoperative visual analog scale scores were significantly lower in the ketamine group than in controls (Wilcoxon-Mann-Whitney odds at 24 hours = 6.25; 95% CI, 4.07 to 1.97; P < 0.0001). Rescue analgesics were required more frequently in controls than in the ketamine group (percentage difference: 58.6%; 95% CI, 43.3% to 69.6%; P < 0.0001). The mean plasma level of ketamine declined rapidly during continuous epidural infusion and decayed slowly after it had stopped.
  
  
  CONCLUSIONS
  Our data show that epidural infusion of subanesthetic doses of S(+)-ketamine during thoracic surgery provides better postoperative analgesia than epidural ropivacaine.
authors.affiliation: Department of Anesthesia and Intensive Care, University Hospital of Padova, via Cesare Battisti 256, Padua, Italy. paolofeltracco@inwind.it
authors.forename: Paolo
authors.initials: P
authors.lastname: Feltracco
authors.forename: Stefania
authors.initials: S
authors.lastname: Barbieri
authors.forename: Stefano
authors.initials: S
authors.lastname: Rizzi
authors.forename: Carlo
authors.initials: C
authors.lastname: Ori
authors.forename: Francesca
authors.initials: F
authors.lastname: Groppa
authors.forename: Giovanni
authors.initials: G
authors.lastname: De Rosa
authors.forename: Anna Chiara
authors.initials: AC
authors.lastname: Frigo
authors.forename: Roberto
authors.initials: R
authors.lastname: Padrini
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015360:Analgesia, Epidural; D000700:Analgesics / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007649:Ketamine / Q000008:administration & dosage* / Q000097:blood; D008297:Male; D008875:Middle Aged; D010149:Postoperative Pain / Q000517:prevention & control*; D059035:Perioperative Period; D019616:Thoracic Surgical Procedures
chemical_list: D000700:Analgesics; D007649:Ketamine