Magnesium Sulfate Potentiates Neuromuscular Blockade With Cisatracurium During Total In Travenous Anesthesia

Objective:The purpose of this study was to investigate that the interaction between magnesium sulfate and cisatracurium by measuring the duration of neuromuscular blockade.in the presence of magnesium, the effect of cisatracurium that the duration of the neuromuscular blockade is enhanced or not.Methods:A total number of sixty ASAⅠ--Ⅱpatients undergoing Laparoscopic surgery(The average operation time 50-70 minutes), anesthesia was induced and maintained with iv midazolam, and fentanyl with the dosages being at the anesthesiologist's discretion. All patients were randomly allocated to receive either magnesium sulfate 40 mg/kg, over three minutes prior toinduction of anesthesia, followed by an infusion of 20mg/kg/h (Group A), or an equal volume of normal saline solution (Group B). preoxygenation 2min,at the same time, open the target controlled infusion (TCI) of propofol and remifentanil:the target concentration were 3.0μg/ml and 4 ng/ml. After patients loss of consciousness, through TCI of propofol, BIS was maintained within 40-60. then, give cisatracurium 0.15 mg/kg and record time, Neuromuscular function was assessed by train-of-four(TOF) stimulation of accelerometry. When TOF=0, the trachea was intubated, Neuromuscular blockade was measured every 12 sec from induction of anesthesia until the end of the skin closure, when neuromuscular function recovered to 25% of the percentage depression of the first response(T1),,administering repeated boluses of cisatracurium 0.05 mg/kg.at the end of the skin closure, Stop infusion magnesium sulfate, saline solution, propofol and remifentanil. After the last dose, duration to 25% spontaneous T1 recovery was also recorded, and given Neostigmine 1mg, Atropine 0.5mg, when patients duration to 75% spontaneous T1 recovery, Spontaneous breathing(tidal volume more than 400ml and a rate of 8-10 breaths/min), and consciousness were achieved. Then, Extubation.Results:1. There were no differences between the study groups with respect to demographic data:The age of patients, BMI(kg/m2), Operation time(min), Sex Ratio;2. When anesthesia was induced, Cisatracurium 0.1 mg/kg iv was administered to facilitate tracheal intubation, time to TOF=0 means Onset time of Cisatracurium, When compared with the control group, there was a significant Shorten in neuromuscular blockade in the group receiving magnesium. The duration to 25% recovery after the intubating dose (0.1 mg/kg) was longer in the magnesium-treated group compared with the placebo group; The effects of the first maintenance dose of cisatracurium (0.05 mg/kg) also lasted longer(P<0.05); Total dose of cisatracurium was significantly less in the magnesium group compared with the placebo group;Conclusion:In patients undergoing Laparoscopic surgery, administration of magnesium sulfate, resulting in Onset time of Cisatracurium, prolongation of the neuromuscular blockade induced with intubating and maintenance doses of cisatracurium and the total dose of cisatracurium was significantly less.