Relationship between Umbilical Artery Pulsatility Index of Doppler Velocimetry and Umbilical Venous Blood Gases Measured by Cordocentesis

Abstract

Cordocentesis of umbilical vein to obtain fetal blood pH, PCOz, and P02 and Doppler eeloctmetrv as a preceding evaluation procedure were performed in 41 fetuses to assess fetal status in utero. The results of the two evaluation techniques, namely pH, PCOz and POz of fetal venous blood and pulsatility index (PI) of Doppler velocimetry, were individually correlated to determine if the procedure of Doppler velocimetry could be performed in lieu of cordocentesis in assessing fetal acid-base status in utero. The indications for cordocentesis were small-for-gestational age fetus (n=9), suspected fetal thrombocytopenia (n=7), isoimmunization (n=5), need for rapidkaryotyping (n=2), paternity determination (n= 1), cancer chemotherapy (n> 1), congenital malformation (n> 15), and nonimmune hydrops fetalis (n> 1). The prevalence of fetal acidemia was 34% (14/41). There was no significant difference in median gestational age at cordocentesis between patients with acidemic fetus and those with nonacidemic fetus (P< 0.5). Significant differences were found in both gas values and PI between acidemic and nonacidemic fetus groups as PI and PCOz were significantly highedP< 0.00001, P<O. ()()()()1) while POz was significantly lower (P< 0.(05) in acidemic fetus group. Linear regression lines drawn to see the relationships between PI and pH, PCOz, POz, respectively, showed fair to good relationships with r values of -0.6334, 0.5747 and -0. 4699, in the same order, all with significance. In conclusion, it is conceivable' that for close and continuous in utero monitoring of hypoxia-complicated fetuses, non-invasive Doppler velocimetry could be performed in place of invasive cordocentesis and also for assisting in decision-making for early delivery to avoid fetal compromise in utero.