EP14.29: Assessment of normal renal function in second trimester ultrasound screening

Abstract

Morphology of kidneys and morphological changes visible by ultrasound in second ultrasound screening are well documented. For monitoring of the renal function there are some ultrasound parameters such as flow examination by Doppler in both arteria renales, urine production per hour resp. per minute, and the pool of amniotic fluid. In our work we tested the possibility to assess two independent parameters of renal function of fetuses in 2nd trimester screening, and have set bounders of normal function. We have assessed 50 fetuses at 19th-20th week gestation and compared the PI of aa. renales and the minute urine volume. All fetuses had morphologically normal kidney, the regularly emptying bladder and normohydramnion. Fetuses with not correctly measured wave by Doppler of both aa renales and smaller volume of urinary bladder after 5 minutes of measurement were excluded. Pulsatility index (PI) was measured by Doppler (exam caliper 2 mm, insonation angle 0°). Urine production was measured according changes of urinary bladder volume during 5 minutes by VOCAL 3Dsystem, with 30 degrees rotation. PI in our assessment (n=50) was 2.66 ± 1.04. Measured minute volume of fetuses was 0.078 ± 0.021 ml/min. Both parameters were measured and documented. Data set of both parameters made a field of normality of renal function. If the measured value exceeds the threshold of this field, we can assume renal impairment. We tried to compare our results with published data, but we didn't find any data for gestation age of our interest. That is why, we have used the extrapolation method of published data and we have found that these are in correlation with our obtained results.