Ffects Of Magnesium Sulfate Infusion On Hemodynamics And Stress Hormone Concentrations To Endotracheal Intubation

Objective To investigate the effects of magnesium sulfate and propofol by TCI for relieving the hemodynamics change and the stress response to endotracheal intubation,when the depth of anesthesia was maintained at BIS 45～55.To investigate the effect of magnesium sulfate on effective-site concentration of propofol by TCI.Methods Sixty ASAⅠ-Ⅱpatients undergoing elective abdominal surgery,were randomly divided into three groups with 20 patients in each group:group C propofol, group M1 propofol+low-dose magnesium sulfate,group M2 propofol+high-dose magnesium sulfate.The patients were premedicated with intramuscular phenobarbital 0.1g and scopolamine 0.3mg.Anesthesia was induced with midazolam 0.05mg·kg^-1, fentanyl 3μ·kg^-1,TCI propofol and vecuronium 0.10mg·kg^-1.The initial target effective-site concentration of propofol was set at 2.0μg·ml^-1 during induction.The patients in group M1 or group M2 were given magnesium sulfate in a dose of 15 or 25mg·kg^-1 bolus,3 minutes before endutracheal intubation..BIS value was maintained at 45-55 by modifying target effect-site concentration of propofol. Laryngoscopy and traeheal intubation were performed when BIS was below 55. SBP,DBP,MAP,HR,Ce and BIS were recorded before anesthetic induction,immidately before intubation,at the moment of intubation,1,3,5,10minutes after intubation.. Meanwhile,ten patients out of each group were taken blood samples from peripheral(6ml)at the time before intubation,3 minutes and 10 minutes after intubation.The plasma concentration of cortisol and angiotensin-Ⅱwere determined.Results①SBP,DBP of group M1 and M2 were not statistically increased at the moment and 1 minute after intubation(P>0.05),but index of group C were increased significantly(P<0.01).Index of group M2 and C were of significant difference(P<0.01) HR was significant increased 1 minutes after intubation compared with baseline values in group C(P<0.05).HR in three groups were of no statistic significance at other time(P>0.05).②The plasma concentration of cortisol increased significantly 3minute after intubation(P<0.05),and it declinded at the time 10 minutes after intubation.,The level of cortisol was declinded 3,10minutes after intubation in group M1 and M2,being of significant difference with group C(P<0. 05).The concentration of A-Ⅱincreased significantly 3,10 minutes after intubation(P<0.05).It was significantly lower in group M1((P<0.05) and group M2 (P<0.01)than that in groupC.③Comparing group C,the effect-site concentration of propofol was decreased at 5,10 minutes after intubation in group M1 and M2 (P<0.01).It was significantly lower in group M2 than that in group M1(P<0.05).Conclusions Comparing with 15mg/kg magnesium sulfate,25mg/kg magnesium sulfate effectively inhibit the stress response to endotracheal intubation.When combined with propofol at the same depth of anesthesia(BIS=45～55),the target effect-site concentration of propofol in group 25mg/kg magnesium sulfate are greatly reduced.