title: Continuous epidural infusion of ropivacaine for the prevention of postoperative pain after major orthopaedic surgery: a dose-finding study.
abstract: OBJECTIVE
  A dose-finding study to investigate the use of epidural infusions of ropivacaine for postoperative analgesia following orthopaedic surgery.
  
  
  METHODS
  This was a randomized, double-blind study. Surgery was performed using a combination of a lumbar epidural block utilizing ropivacaine 0.5% and a standardized general anaesthetic. Postoperatively, an epidural infusion of the study solution (saline, ropivacaine 0.1%, 0.2% or 0.3%) was started at the rate of 10 ml.hr-1 and continued for 21 hr after arrival in the PACU. Analgesia was supplemented with PCA morphine (dose = 1.0 mg, lock-out = 5 min).
  
  
  RESULTS
  Forty-four patients completed the study. The ropivacaine 0.1%, 0.2%, 0.3% groups required less morphine over the 21 hr than the saline group (P < 0.01). The VAS pain scores were also lower in the three ropivacaine groups (P < 0.001). The ropivacaine groups maintained sensory anaesthesia to pinprick when compared with saline (P < 0.05). The motor block in the 0.3% group was significantly higher than the saline group at all times (P < 0.05), and higher than the 0.1% group at eight hours (P < 0.01), while the 0.2% group had higher Bromage scores than saline at 4 and 21 hr (P < 0.05).
  
  
  CONCLUSIONS
  The use of continuous epidural infusions of ropivacaine 0.1%, 0.2% and 0.3% at 10 ml.hr-1 improved postoperative pain relief and decreased PCA morphine requirements in patients undergoing major orthopaedic surgery. The 0.1% and 0.2% concentrations produced similar sensory anaesthesia with less motor blockade than the 0.3% concentration.
authors.affiliation: Department of Anaesthesia, University Hospital, London, Ontario, Canada.
authors.forename: N H
authors.initials: NH
authors.lastname: Badner
authors.forename: D
authors.initials: D
authors.lastname: Reid
authors.forename: P
authors.initials: P
authors.lastname: Sullivan
authors.forename: S
authors.initials: S
authors.lastname: Ganapathy
authors.forename: E T
authors.initials: ET
authors.lastname: Crosby
authors.forename: J
authors.initials: J
authors.lastname: McKenna
authors.forename: A
authors.initials: A
authors.lastname: Lui
mesh_terms: D000328:Adult; D000368:Aged; D000577:Amides / Q000008:administration & dosage*; D015360:Analgesia, Epidural; D000779:Anesthetics, Local / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009985:Orthopedics; D010149:Postoperative Pain / Q000517:prevention & control*; D000077212:Ropivacaine
chemical_list: D000577:Amides; D000779:Anesthetics, Local; D000077212:Ropivacaine