Zuspan's Scheme Versus an Alternative Magnesium Sulfate Scheme: Randomized Clinical Trial of Magnesium Serum Concentrations

Objective. The purpose of this study was to determine whether magnesium serum concentrations in patients with severe preeclampsia or eclampsia treated with two different magnesium sulfate schemes were different. Methods. Fourteen patients were randomly assigned in the alternative scheme group and 15 in the Zuspan's group. The difference between the groups was that the intravenously administered maintenance dose was done with 1 g/h by continuous intravenous infusion in the Zuspan's group and 2g in bolus every two hours in the alternative scheme. Blood samples were collected previously to treatment and every 15 minutes during four hours after the beginning of treatment. The primary outcome measure was area under the curve and the t-test was used for statistical analysis with level of statistical significance of 5%. The evaluation of the punctual means at all moments in the alternative group was done with the repeated measures analysis of variance. Results. There was no significant difference in the baseline characteristics between groups. In both schemes, magnesium serum concentration reaches a peak within 15 minutes and a new peak was observed after maintenance dose in the alternative scheme. The area under the curve was significantly lower in the alternative scheme than in the Zuspan's scheme (702.1 +/- 73.5 mg/dL vs 796.1 +/- 94.6 mg/dL). Conclusion. The serum magnesium concentration of this randomized clinical trial doesn't support the use of the alternative scheme of magnesium sulfate to prevent or treat eclampsia.