| Objective To investigate the effects of continuous intravenous infusion of magnesium sulfate on effective-site concentration of propofol by TCI and hemodynamics,when the depth of anesthesia was maintained at BIS 45～55. To explore the optimal dose of magnesium sulfate with propofol in total intravenous anesthesia.Methods Sixty ASA I -Ⅱpatients undergoing elective abdominal surgery, were randomly divided into three groups with 20 patients in each group: group P 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 0.06mg kg-1, fentanyl 3μg·kg-1 and vecuronium 0.12mg·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, followed by a continuous infusion of 6 or 9mg·kg-1·h-1. BIS value was maintained at 45-55 by modifying target effect-site concentration of propofol. Ce, MAP, HR, SpO2, PetCO2 and BIS were recorded before anesthetic induction (T0), before and after intubation (T1, T2), before and after skin incision (T3, T4), at 30rain after incision(T5), at 60rain after incision(T6), at end of operation(T7). Meanwhile, total doses of propofol, the usage of vasoactive agents and the concentration of Mg2+,Ca2+ in serum at the end of operation were recorded.Results①Comparing group P, the effect-site concentration of propofol was decreased at every point of group M2 (P＜0.05 or P＜0.01 ) and at some points of group M1 (P＜0.05) . There was no awareness during surgery among these patients.②The total doses of propofol were (6.074±0.68) mg·kg-1·h-1, (4.114±0.41)mg, kg.(-1)·h-1 and (3.704±0.63)mg·kg-1·h-1 respectively in group P, group M1 and group M2.It was significantly lower in group M1 and group M2 than that in group P(P＜0.01), lower in group M2 than that in group M1 (P＜0.05)③Hemodynamics in group M2 was much more stable than the other groups. Hypertention were more frequent in group P(7 cases) and M1 (5 cases) than that in group M2 (0 case) during operation. There was no difference in the usage of atropine and dopamine among three groups.④The concentration of Mg2+ in serum of all the patients were in the safety range; but the concentration of Ca2+ was decreased among three groups.Conclusions When combined with propofol at the same depth of anesthesia (BIS=45～55), the target effect-site concentration of propofol and the total doses of propofol in group large-dose magnesium sulfate are greatly reduced and more stable hemodynamics in this group during operation. There is no hypermagnesemia with apparent clinical effect by these doses of magnesium sulfate during operation.
|
PDF Full Text Request