title: Priming with rocuronium accelerates neuromuscular block in children: a prospective randomized study.
abstract: OBJECTIVE
  To determine the effects of a priming technique with respect to onset time and duration of action of rocuronium (1.5 x ED(95), 2.0 x ED(95)) in a pediatric patient population.
  
  
  METHODS
  Eighty-four children, age one to seven years undergoing elective pediatric surgery, were studied in a randomized controlled trial. Neuromuscular function was assessed by accelerometry in response to single-twitch stimulation to assess onset of neuromuscular block, followed by train-of-four (TOF) stimulation at the wrist every 15 sec. Children were randomly allocated to one of four groups: Groups 1 and 3 received saline placebo, followed one minute later by a single bolus dose of rocuronium 0.45 mg.kg(-1) iv (1.5 x ED(95)) and 0.6 mg kg(-1) iv (2.0 x ED(95)), respectively. Patients in Groups 2 and 4 received an initial dose of rocuronium 0.045 mg.kg(-1) iv and 0.06 mg.kg(-1) iv, respectively, followed one minute later by rocuronium 0.405 mg.kg(-1) and 0.54 mg.kg(-1)iv, respectively.
  
  
  RESULTS
  Rocuronium priming significantly accelerated the time to maximum rocuronium-induced neuromuscular block when compared to placebo [median (95% confidence interval)]: 122.5 (98-186) vs 92.5 (68-116) sec (1.5 x ED(95), Group 1 vs Group 2, P < 0.05) and 85 (60-142) vs 55 (48-72) sec (2.0 x ED(95), Group 3 vs Group 4, P < 0.05), respectively. Spontaneous recovery to a TOF-ratio >or= 0.9 was dose-dependent and not influenced by priming.
  
  
  CONCLUSIONS
  Priming accelerated the onset of rocuronium in children. A priming interval of one minute and a cumulative dose of rocuronium 1.5 x ED(95) resulted in an onset of neuromuscular block comparable to a single dose of rocuronium (2.0 x ED(95)).
authors.affiliation: Department 1 of Anesthesiology, Bozen Central Hospital, Bozen, Italy. matthias.bock@asbz.it
authors.forename: Matthias
authors.initials: M
authors.lastname: Bock
authors.forename: Lars
authors.initials: L
authors.lastname: Haselmann
authors.forename: Bernd W
authors.initials: BW
authors.lastname: Böttiger
authors.forename: Johann
authors.initials: J
authors.lastname: Motsch
mesh_terms: D000732:Androstanols; D002648:Child; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D023381:Endpoint Determination; D005260:Female; D006801:Humans; D008297:Male; D016343:Monitoring, Intraoperative; D009407:Nerve Block; D003473:Neuromuscular Nondepolarizing Agents; D011229:Preanesthetic Medication; D011446:Prospective Studies; D000077123:Rocuronium
chemical_list: D000732:Androstanols; D003473:Neuromuscular Nondepolarizing Agents; D000077123:Rocuronium