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].