title: Determination of the full dose-response relation of intrathecal bupivacaine, levobupivacaine, and ropivacaine, combined with sufentanil, for labor analgesia.
abstract: BACKGROUND
  Ropivacaine and levobupivacaine are local anesthetics that produce less motor block and greater sensory-motor separation when compared with equal milligram doses of bupivacaine. Although minimum local analgesic concentration studies suggested that they are less potent than bupivacaine, full dose-response studies have not been performed. The current trial describes the dose-response relation of levobupivacaine, ropivacaine, and bupivacaine, combined with sufentanil, when used for intrathecal labor analgesia.
  
  
  METHODS
  Four hundred fifty term parturients in active labor were included in this double-blind, randomized trial. Combined spinal-epidural anesthesia was performed, and ropivacaine, levobupivacaine, or bupivacaine was intrathecally administered in a dose of 1.0, 1.5, 2.0, 2.5, 3.0, or 3.5 mg, always combined with 1.5 microg sufentanil. Patients were considered responders to spinal analgesia if the visual analog scale score for pain was less than 25 mm within 15 min and the visual analog scale score remained less than 25 mm for 45 min. Patient demographics, obstetric data, maternal side effects, and fetal and neonatal well-being were noted. Group-specific dose-response curves were constructed using a probit regression model.
  
  
  RESULTS
  The ED95 of bupivacaine was 3.3 mg (95% confidence interval, 2.9-4.1). The ED95s of ropivacaine and levobupivacaine were 4.8 mg (95% confidence interval, 4.0-6.7) and 5.0 mg (95% confidence interval, 4.1-7.0), respectively. Racemic bupivacaine was significantly more potent than ropivacaine (P=0.0027) and levobupivacaine (P=0.0006). Ropivacaine and levobupivacaine were of similar potency (P=0.91).
  
  
  CONCLUSIONS
  This full dose-response study suggests that ropivacaine and levobupivacaine are of similar potency, whereas bupivacaine is more potent than both other drugs.
authors.affiliation: Department of Anesthesiology, University Hospitals Leuven, Katholieke Universiteit Leuven, Belgium. marc.vandevelde@uz.kuleuven.ac.be
authors.forename: Marc
authors.initials: M
authors.lastname: Van de Velde
authors.forename: Rebekka
authors.initials: R
authors.lastname: Dreelinck
authors.forename: Jasperina
authors.initials: J
authors.lastname: Dubois
authors.forename: Ariane
authors.initials: A
authors.lastname: Kumar
authors.forename: Jan
authors.initials: J
authors.lastname: Deprest
authors.forename: Liesbeth
authors.initials: L
authors.lastname: Lewi
authors.forename: Eugene
authors.initials: E
authors.lastname: Vandermeersch
mesh_terms: D000293:Adolescent; D000328:Adult; D000577:Amides / Q000008:administration & dosage*; D015360:Analgesia, Epidural; D016362:Analgesia, Obstetrical; D000779:Anesthetics, Local / Q000008:administration & dosage*; D002045:Bupivacaine / Q000008:administration & dosage* / Q000031:analogs & derivatives; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007278:Injections, Spinal; D000077554:Levobupivacaine; D008875:Middle Aged; D011247:Pregnancy; D000077212:Ropivacaine; D017409:Sufentanil / Q000008:administration & dosage*
chemical_list: D000577:Amides; D000779:Anesthetics, Local; D000077212:Ropivacaine; D000077554:Levobupivacaine; D017409:Sufentanil; D002045:Bupivacaine