Precision of umbilical artery Doppler studies. Intraobserver, interobserver, and biologic variability of fetal Doppler velocimetry.

Abstract

The use of Doppler ultrasound to study fetal blood flow has become commonplace, despite the lack of detailed evaluation of the testing tool for precision. In evaluation of 25 patients, no significant intraobserver differences were found between readings on an individual waveform, nor were there significant differences between different observers on individual waveforms. Temporally separated waveforms within a 30-minute window gave the greatest variation. A multi-way analysis of variance noted significant differences in this category only. This study confirmed the precision of measurements by a single observer and between observers. Only biological alterations over time displayed significant variability.

Hemodynamic Impact of Absent or Reverse End-Diastolic Flow in the Two Umbilical Arteries in Growth-Restricted Fetuses

“…Recommendations on how to perform the exam have been published [4]. In particular, it was suggested that the UAs should be sampled in a free-floating loop of the umbilical cord (FFC), since the indices are higher when sampling occurs at the fetal end and lower at the placental end of the umbilical cord[5-11]. These differences are significant regardless of gestational age but do not seem to have an impact in clinical practice.…”

Assessment of Blood Flow Velocity Waveforms of the Pulmonary Circulation by Multigate Spectral Doppler Scanning and Traditional Pulsed Doppler Ultrasonography

“…The relatively low reproducibility of Doppler ultrasonography in the fetus was previously reported by Thomas et al 20 and Ruissen et al 21 The intraobserver error for the blood flow impedance assessment of a highly vascularized region has also been reported to be high. 22 Therefore, a single Doppler flow measurement could result in error.…”

“…Past studies have shown that the total error variance of Doppler indices is composed of many factors, including differences in experience between examiners, physiologic hemodynamic changes, the location error of Doppler measurements, interpatient variance, intraobserver error, and statistical error. 19,20 In this study, we controlled the factors of interobserver error and interpatient variance. Because the MSD scanning time is relatively short (<20 seconds), physiologic hemodynamic changes during this time should be small.…”

Extracardiac Doppler indices predict perinatal mortality in fetuses with Ebstein anomaly and tricuspid valve dysplasia

“…The presence of PR may be at times difficult to discern, particularly if the fetal position or acoustic windows are unfavorable or if the pulmonary valve is not well seen. However, acquisition of the UA pulsed Doppler is usually easier and less user‐dependent which could prove to be a more reliable surrogate for assessing the presence and degree of PR 21 …”

“…In severe cases of EA/TVD, the umbilical vein sees decreased upstream flow and pressure from the placenta as well as increased downstream pressure from elevated central venous pressure which results in a relatively lower pressure differential (red solid line) compared to EA/TVD patients with less severe pathophysiology (red dashed line) [Colour figure can be viewed at wileyonlinelibrary.com] dependent which could prove to be a more reliable surrogate for assessing the presence and degree of PR. 21 It is plausible that the abnormal UA pattern in non-survivors is also influenced by placental dysfunction. Abnormal UA flow has been associated with many placental pathologies, 22 and in particular, the placentas of newborns with CHD have been shown in several studies to be more likely abnormal.…”