THE HIGH-RESISTANCE STATE INDEX - A NEW METHOD TO ASSESS FETAL COMPROMISE IN ABSENT END-DIASTOLIC UMBILICAL ARTERIAL FLOW

Objective: To quantify the entire Doppler blood flow velocity waveform by using a new concept of waveform analysis, the High Resistance Stat e Index (HRSI). Methods: The HRSI was calculated prospectively for 16 patients with absent end diastolic flow (AEDF) in the umbilical arteri es who developed cardiotocographic signs of fetal distress or intraute rine death, The HRSI was compared with the time interval to cardiotoco graphic signs of fetal distress or intrauterine death. Results: There was a trend for a shorter time interval to cardiotocographic signs of fetal distress or intrauterine death with increasing HRSI values. Conc lusions: The HRSI can play a complementary role in fetal surveillance in cases of AEDF in the umbilical arteries by characterizing further c hanges in the Doppler waveform shape, which may be attributable to cha nges in the umbilical-placental vascular resistance. A high HRSI indic ates a trend for a more rapid fetal deterioration. Intensive fetal mon itoring in a tertiary care center or immediate delivery after the meas urement of a high HRSI may be of benefit to a viable fetus.