title: Effects of single-shot and steady-state propofol anaesthesia on rocuronium dose-response relationship: a randomised trial.
abstract: BACKGROUND
  Similar to volatile anaesthetics, propofol may influence neuromuscular transmission. We hypothesised that the administration of propofol influenced the potency of rocuronium depending on the duration of the administration.
  
  
  METHODS
  After consent, patients scheduled for elective surgery randomly received rocuronium either after induction of anaesthesia with propofol (2 min of propofol, n = 36) or after 30 min of propofol infusion (30 min of propofol, n = 36). Remifentanil was given in both groups. Neuromuscular monitoring was performed by calibrated electromyography. The dose-response relationship of rocuronium was determined with a single-bolus technique (0.07, 0.1, 0.15, 0.2, 0.3 and 0.45 mg/kg rocuronium). The primary endpoints were the ED50 and ED95 of rocuronium after 2 and 30 min propofol. Data are presented as means with (95% confidence interval). The trial is registered with the Eudra-CT: 2009-012815-16.
  
  
  RESULTS
  A total of 72 patients were included. Time to maximal neuromuscular blockade was significantly shorter in patients after 30 min of propofol [3.3 min (2.9-3.7)] compared with patients anaesthetised with 2 min of propofol [4.6 min (4.0-5.2)]. After 30 min of propofol, the slope of the dose-response curve was significantly steeper (30 min of propofol: 4.34 [3.62-5.05]; 2 min of propofol: [3.34 (2.72-3.96)], resulting in lower ED95 values of rocuronium (30 min of propofol: 0.287 mg/kg [0.221-0.368]; 2 min of propofol [0.391 mg/kg (0.296-0.520)]. The ED50 were not different between groups.
  
  
  CONCLUSIONS
  The potency of rocuronium was significantly enhanced after propofol infusion for 30 min. Estimates of potency those are usually determined during steady-state anaesthesia might underestimate rocuronium requirements for endotracheal intubation at the time of induction.
authors.affiliation: Klinik für Anaesthesiologie, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: C G
authors.initials: CG
authors.lastname: Stäuble
authors.affiliation: Klinik für Anaesthesiologie, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: R B
authors.initials: RB
authors.lastname: Stäuble
authors.affiliation: Klinik für Anaesthesiologie, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: S J
authors.initials: SJ
authors.lastname: Schaller
authors.affiliation: Klinik für Anaesthesiologie, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Unterbuchner
authors.affiliation: Klinik für Anaesthesiologie, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Fink
authors.affiliation: Klinik für Anaesthesiologie, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Blobner
mesh_terms: D000328:Adult; D000368:Aged; D000732:Androstanols / Q000494:pharmacology*; D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004357:Drug Synergism; D004576:Electromyography / Q000187:drug effects; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal; D008297:Male; D008875:Middle Aged; D019148:Neuromuscular Blockade / Q000379:methods*; D003473:Neuromuscular Nondepolarizing Agents / Q000494:pharmacology*; D015742:Propofol / Q000494:pharmacology*; D000077123:Rocuronium; D013997:Time Factors; D055815:Young Adult
chemical_list: D000732:Androstanols; D018686:Anesthetics, Intravenous; D003473:Neuromuscular Nondepolarizing Agents; D000077123:Rocuronium; D015742:Propofol