Magnesium sulfate seizure prophylaxis and ultrasonographic evaluation
Magnesium sulfate prophylaxis was applied intravenously at 4.5 grams as loading dose and at 2 grams/hour continuous dose. Maternal serum and fetal mod- MPI calculations were obtained just before the seizure prophylaxis was given and at the second hour after the prophylaxis.
Mod-MPI measurement was done by a perinatologist experienced in mod-MPI calculation, fetal echocardiography and Doppler ultrasonography. Voluson E6 (GE Medical Systems, Waukesha, WI, USA) and a curvilinear probe of 6-9 MHz was utilized in ultrasonographic evaluation of the fetal heart when the fetus was still and the fetal heart was apical. The Doppler sample size was opened at 3-5 mm and placed on the lateral wall of the ascending aorta covering both mitral and aortic valves [18]. Ultrasonographic examination complied with the instructions of the International Society of Ultrasound and Obstetrics and Gynecology (ISUOG) Practice Guidelines [19]. Modified MPI measurement was done using the left ventricle and as described by Hernandez-Andrade et al [14,15). The insonation angle was between 0 and 15 degrees. Doppler gain was adjusted for clear appearance of valve clicks, sweep velocity was 5 cm/s and wall motion filter was 300 Hz. The period between mitral valve closure and opening of the aortic valve was the isovolumetric contraction time (ICT). The isovolumetric relaxation time (IRT) was described as the period between aortic valve closure and opening of the MV. Ejection time (ET) was the period between opening and closure of the aortic valve. The formula (ICT+IRT)/ET was used for the mod-MPI calculation [12].