CLINICAL-APPLICATION OF PULSATILITY INDEX OF FLOW-VOLUME TO DETECT THE HEMODYNAMIC-CHANGES IN IUGR FETUS

We attempted to assess fete-placental circulation in fetuses with intr auterine growth retardation (IUGR) by calculating the pulsatility inde x of flow volume (PIQ) based on the quantitative measurement of blood flow. Doppler sound was processed by an analog to digital converter an d a frequency analyzer. Multiplication of frequency and signal strengt h of the Doppler sound at a certain time theoretically represents a va lue proportional to flow volume. Using this value, we calculated PIQ o f the descending aorta, umbilical artery, and middle cerebral artery i n normal fetuses, IUGR fetuses, and distressed fetuses during 24-41 we eks gestation. The PIQ of the fetal descending aorta in the IUGR fetus was significantly higher than that of the normal fetus. When cutoff V alue was set to mean + 1 SD, abnormal PIQ was observed in 88% of IUGR fetuses. In contrast, the abnormal pulsatility index of maximal flow v elocity (PIV) of the descending aorta was observed in only 62% of IUGR fetuses. In the distressed fetuses, both PIQ and PIV of the umbilical artery increased, and these indices of the middle cerebral artery mar kedly decreased. It is suggested that the increased PIQ of the descend ing aorta is an early indicator of changes in the fetal circulation in IUGR fetuses.