Pulmonary function in preeclamptic women receiving MgSO4

Pulmonary function was studied in ten preeclamptic women in labor receiving continuous infusions of MgSO4 (group I) and six normotensive, healthy parturients in labor (group II). In group I, the forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and maximum voluntary ventilation (MVV) were measured prior to, two hours after and six hours after the start of infusions. The mean FVC decreased from a baseline value of 3.05 +/- 0.41 to 2.67 +/- 0.50 L (P less than .005) at two hours and to 2.71 +/- 0.42 L (P less than .005) at six hours; the mean FEV1 decreased from a control value of 2.50 +/- 0.41 to 2.25 +/- 0.45 L at two hours (P less than .01) and to 2.25 +/- 0.37 L at six hours (P less than .01). The mean MVV decreased from a baseline value of 93.75 +/- 15.6 to 84.4 +/- 17.1 L at two hours (P less than .01) and 83.75 +/- 13.5 L at six hours (P less than .02). There were no significant differences between the two- and six-hour values. There was no change in the percentage of FEV1: FVC at any time during the measurement. The mean serum magnesium level was 3.66 +/- 0.44 mg/dL. In the control group (group II), the FVC, FEV1 and MVV values were within normal limits, and there were no significant changes from baseline measurements at two and six hours. The results indicate a decrease in pulmonary function in preeclamptic patients in labor receiving MgSO4 infusions.