title: Rocuronium priming of atracurium-induced neuromuscular blockade: the use of short priming intervals.
abstract: OBJECTIVE
  To evaluate the effects of priming doses of rocuronium on the duration of priming interval and on the outcome of priming sequence using rocuronium-atracurium combination.
  
  
  METHODS
  Three phase, randomized, controlled study.
  
  
  METHODS
  Inpatient anesthesia in a university hospital.
  
  
  METHODS
  144 ASA physical status I and II patients, 19 to 57 years of age, weighing 50 to 90 kg, and undergoing low-risk elective surgery.
  
  
  METHODS
  Phase I, two equal groups (n = 12) of adult patients anesthetized with propofol, fentanyl, and nitrous oxide (N2O), received a priming dose of rocuronium 0.1 mg/kg or vecuronium 0.015 mg/kg. Phase II included six equal groups (n = 12): Groups 1, 2, and 3 received a priming dose of rocuronium 0.1 mg/kg and atracurium 0.42 mg/kg for intubation. The priming intervals were, respectively, 1, 1.5, or 2 minutes in Groups 1, 2, and 3. Groups 4, 5, and 6 received, respectively, a bolus dose of rocuronium 0.6 mg/kg, atracurium 0.5 mg/kg, or succinylcholine 1 mg/kg. Intubation was performed at maximum block. Phase III included four equal groups (n = 12). A priming dose of rocuronium 0.1 mg/kg (Group 1) or a placebo (Groups 2, 3, and 4) was given to awake patients. Anesthesia was induced during the one-minute priming interval. Intubating doses of atracurium 0.42 mg/kg, rocuronium 0.6 mg/kg, atracurium 0.5 mg/kg, or succinylcholine 1 mg/kg were given to Groups 1, 2, 3, and 4, respectively. Intubation was attempted 1 minute after intubating doses were administered.
  
  
  RESULTS
  Adductor pollicis response to train-of-four stimulation was recorded mechanically in Phases I and II only. The priming interval after rocuronium 0.1 mg/kg was in the range of 1 to 2 minutes. Priming doses of rocuronium resulted in significant acceleration in the onset time of intubating doses of atracurium, irrespective of the duration of the priming interval. The onset times [mean (SD)] following rocuronium-atracurium sequence in Groups 1, 2, and 3 were, respectively, 67 (17), 73 (14), and 66 (18) seconds and were comparable with the onset of bolus doses of rocuronium and succinylcholine. In Phase II, good to excellent intubating conditions were obtained in 41% to 58% of patients included in Groups 1 through 5. Excellent to good intubating conditions were obtained in all patients (100%) who received succinylcholine. In Phase III, good to excellent intubating conditions were obtained in 91% of patients who received recuronium-atracurium sequence. Symptoms of muscle weakness were not reported.
  
  
  CONCLUSIONS
  Priming doses of recuroniums 0.1 mg/kg reduce the priming interval to 1 minute, allow early induction of anesthesia, eliminate patient discomfort, and accelerate the onset time of altracurium with intubating conditions comparable with succinylcholine and rocuronium.
authors.affiliation: Department of Anesthesia, Faculty of Medicine, Cairo University, Egypt.
authors.forename: M
authors.initials: M
authors.lastname: Abdulatif
authors.forename: A
authors.initials: A
authors.lastname: al-Ghamdi
authors.forename: M
authors.initials: M
authors.lastname: el-Sanabary
mesh_terms: D000328:Adult; D000732:Androstanols / Q000008:administration & dosage*; D000768:Anesthesia, General; D001279:Atracurium / Q000008:administration & dosage*; D004338:Drug Combinations; D017558:Elective Surgical Procedures; D004558:Electric Stimulation; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D007442:Intubation, Intratracheal; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects; D019148:Neuromuscular Blockade; D003473:Neuromuscular Nondepolarizing Agents / Q000008:administration & dosage*; D010919:Placebos; D000077123:Rocuronium; D013390:Succinylcholine / Q000008:administration & dosage; D013997:Time Factors; D014459:Ulnar Nerve / Q000187:drug effects; D014673:Vecuronium Bromide / Q000008:administration & dosage
chemical_list: D000732:Androstanols; D004338:Drug Combinations; D003473:Neuromuscular Nondepolarizing Agents; D010919:Placebos; D001279:Atracurium; D014673:Vecuronium Bromide; D013390:Succinylcholine; D000077123:Rocuronium