Variance Studies For Fetal Doppler Measurements - GE LOGIQ 500 Advanced Reference Manual

Bioeffects

Variance studies for fetal Doppler measurements

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The following guidance
potential variation of results when performing fetal Doppler
measurements among the same or between different users. In
order to complete this assessment, each clinic intending to use
this system for fetal Doppler should conduct a clinical trial to
establish the intra- and inter-operator variances.
The recommended protocol for such a clinical trial is:
1. Select at least 20 high-risk patients.
2. For each patient, select at least one Doppler waveform
from the same fetal artery.
3. For each waveform, have each of at least three trained
sonographers independently complete at least three
repeat measurements for each of the Doppler
calculations (e.g., S/D Ratio, PI, RI, etc.).
4. Perform an appropriate Analysis of Variance (ANOVA)
over all 20 patient waveforms and also for each patient
waveform separately.
5. Use the results of the ANOVA to estimate both intra-
and inter-operator error variance components. (The
SAS procedure VARCOMP may be used.)
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is provided to help users assess the
LOGIQ 500 Advanced Reference Manual
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