Rocuronium priming of atracurium-induced neuromuscular blockade: the use of short priming intervals.
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.
Abdulatif
M
M
Department of Anesthesia, Faculty of Medicine, Cairo University, Egypt.
al-Ghamdi
A
A
el-Sanabary
M
M
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
D000732:Androstanols; D004338:Drug Combinations; D003473:Neuromuscular Nondepolarizing Agents; D010919:Placebos; D001279:Atracurium; D014673:Vecuronium Bromide; D013390:Succinylcholine; D000077123:Rocuronium