A randomized trial to identify optimal precurarizing dose of rocuronium to avoid precurarization-induced neuromuscular block.

Author(s): Fukano N, Suzuki T, Ishikawa K, Mizutani H, Saeki S, Ogawa S

Affiliation(s): Department of Anesthesiology, Surugadai Nihon University Hospital, 1-8-13, Kanda-Surugadai, Chiyoda-Ku, Tokyo 101-8309, Japan.

Publication date & source: 2011-04, J Anesth., 25(2):200-4. Epub 2011 Jan 12.

Publication type: Randomized Controlled Trial

PURPOSE: The aim of this study was to examine the safe precurarizing dose of rocuronium required to avoid neuromuscular block after precurarization. METHODS: Twenty-four female patients were randomly allocated into two groups of 12 patients each. General anesthesia was induced and maintained with remifentanil and propofol, and a laryngeal mask was inserted without the aid of a neuromuscular blocking agent. Patients were randomized to receive either 0.03 or 0.06 mg/kg rocuronium as a precurarizing dose. Neuromuscular block was monitored using acceleromyographic train-of-four (TOF) of the adductor pollicis muscle. Three minutes after the precurarization, all patients received suxamethonium 1.5 mg/kg and were graded on severity of fasciculations. RESULTS: The average TOF ratio was kept above 0.9 even 3 min after precurarization with 0.03 mg/kg rocuronium. In contrast, in patients who received 0.06 mg/kg rocuronium, the ratios significantly decreased to 0.72 (0.14) [mean (SD), P < 0.004] and 0.68 (0.18) (P < 0.006) 2 min and 3 min after the precurarization, respectively. No visible muscle movement was observed following suxamethonium injection, except that one patient who received 0.03 mg/kg rocuronium showed very fine muscle movements of the fingertips. CONCLUSION: Rocuronium at 0.06 mg/kg is an overdose for precurarization. The results of the present study demonstrate that a safe and effective precurarizing dose of rocuronium is 0.03 mg/kg.