Magnesium sulfate accelerates the onset of low-dose rocuronium in patients undergoing laryngeal microsurgery

Abstract

Study objectiveWe evaluated the effect of magnesium sulfate—an enhancer of neuromuscular blockade—on onset and duration of low dose of rocuronium, and on operating conditions during laryngeal microsurgery. DesignRandomized, prospective, double-blinded study. PatientsEighty-four patients scheduled for elective laryngeal microsurgery. InterventionsPatients were randomly allocated to receive different doses of rocuronium: 0.6 mg/kg (group C, n=28), 0.45 mg/kg (group LR, n=28), or 0.45 mg/kg plus magnesium sulfate 30 mg/kg (group LM, n=28). MeasurementsWe measured the onset time and duration of action of rocuronium, and evaluated the surgeon's satisfaction with the operating conditions. Main resultsGroup LR showed significantly delayed onset time (group C: 87±22 seconds, group LR: 127±47 seconds, and group LM: 89±32 seconds; P=.001) and maximal suppression than did other groups (group C: 102±30 seconds, group LR: 155±66 seconds, and group LM: 105±36 seconds; P=.002). Duration of action of rocuronium was significantly longer in group C than in other groups (group C: 39±7 minutes, group LR: 28±8 minutes, group LRM: 31±8 minutes; P<.001). Laryngoscope placement score (P=.002), surgeon's satisfaction (P=.005), and sore throat (P=.035) were significantly worse in group LR. ConclusionsMagnesium sulfate 30 mg/kg accelerated the onset and improved operating conditions of low-dose rocuronium without prolongation of action.