Comparison of succinylcholine with two doses of rocuronium using a new method of monitoring neuromuscular block at the laryngeal muscles by surface laryngeal electromyography

Abstract

We compared the onset of onset of neuromuscular block with succinylcholine (I mg kg-1) and two doses of rocuronium (0.6 and 0.9 mg kg-1) at the adductor pollicis muscle using electromyography (EMG) and acceleromyography (AMG), and at the adductor laryngeal muscles with a new electromyographic method using a disposable surface electrode attached to the cuff of a tracheal tube. At the larynx, the mean (±SD) time to 90% block and the onset time of succinylcholine (38±15 and 47±19 s, respectively) were significantly shorter (P<0.01) than for rocuronium 0.6 mg kg-1 (92±42 and 106±38 s) and rocuronium 0.9 mg kg-1 (52±31 and 64±30 s). We found that, with comparable degrees of neuromuscular block, the onset time of succinylcholine at the adductor pollicis was significantly shorter (P<0.01) than for rocuronium 0.6 mg kg-1 and 0.9 mg kg-1 (EMG, 80±39 vs 145±48 s and 99±31 s; AMG, 90±39 vs 124±53 s and 106±38 s). Clinical duration at the adductor pollicis (AMG) was significantly longer (P<0.01) for both rocuronium groups than for succinylcholine (T4:T1=0.7, 54±18 and 77±21 vs 8±6 min). The surface laryngeal electrode proved non-invasive, easy to use and reliable in measuring onset of the neuromuscular block at the larynx.