Background and Goal of Study: Deep and intense neuromuscular blockade benefits surgical procedures as robotic and video surgeries. Magnesium sulphate increases the duration of neuromuscular blockade, but its effect on each phase of neuromuscular blockade is not described
To determine the duration of deep and intense neuromuscular blockade following a single dose of rocuronium with pre-treatment with intravenous infusion of magnesium sulphate.
Materials and Methods:Clinical, prospective, comparative, randomised and double-blind study.
Sixty patients participated in the study. All were submitted to elective otorhinolaryngological surgeries under general anesthesia.The Stockholm revision protocol was adopted. Before anesthesic induction, patients were pre-treated with intravenous infusion of 100 ml of saline (control group) or intravenous infusion of 60 mg.kg-1 of magnesium sulphate diluted in 100 ml of saline(sulphate group). A rocuronium bolus (0.6mg.Kg-1) was administered after loss of consciousness. The neuromuscular function was evaluated by accelerometer of the thumb adductor with the TOF Watch SX monitor. The duration of deep neuromuscular blockade was defined as the time period from the reappearance of the first response to PTC stimulation until the reappearance of the first response to TOF stimulation.The duration of intense neuromuscular blockade was defined as the time period where there is no response to PTC stimulation. The data were analyzed using the Mann-Whitney test
Results and Discussion:The mean duration in minutes of the deep neuromuscular blockade in the magnesium sulphate group was 23.91 (95% CI=19.04,28.79) and in the control group it was 18.70 (95%CI =14.79,22.62) p value 0,1809.The mean duration of intense neuromuscular blockade in sulphate group was 20.35 (95%CI = 14.32,26.38) and  control group  was 7.67 (95%CI =4.04, 11.31) p value 0,0011 
Conclusion(s): Magnesium sulphate increases the duration of intense neuromuscular blockade allowing a mean increase of 12,67 min in the duration.There was no statistical difference between the studied groups with deep neuromuscular blockade.


09 / Effect of pre-treatment with magnesium sulphate on the duration of deep and intense neuromuscular blockade with rocuronium : a randomized, double-blind clinical study