FE Hemodynamics & Blood Flow Flashcards

Which Doppler parameter best reflects fetal diastolic cardiac function?

Answer: Tricuspid E/A ratio

The tricuspid E/A ratio (ratio of early passive to late active filling velocities) is used to assess fetal diastolic ventricular function.

In the normal fetus, the tricuspid E/A ratio is typically:

Answer: Less than 1.0 in early gestation, approaching 1.0 at term

The tricuspid E/A ratio is less than 1.0 early in gestation (A-wave dominant) and increases toward 1.0 at term as ventricular compliance improves.

What does pulsatility in the umbilical vein waveform indicate?

Answer: Elevated right atrial pressure or cardiac insufficiency

Umbilical vein pulsatility indicates transmission of right atrial pressure waves through the ductus venosus, suggesting cardiac insufficiency or elevated venous pressure.

Which fetal vessel is used to screen for fetal anemia using peak systolic velocity (PSV)?

Answer: Middle cerebral artery

Middle cerebral artery peak systolic velocity (MCA-PSV) is the standard non-invasive method for detecting fetal anemia due to increased cardiac output and reduced blood viscosity.

At what MCA-PSV multiple of the median (MoM) is moderate-to-severe fetal anemia suspected?

Answer: Greater than 1.5 MoM

An MCA-PSV greater than 1.5 MoM is the established threshold for suspecting moderate-to-severe fetal anemia requiring further evaluation.

Which condition causes increased MCA-PSV due to hyperdynamic circulation rather than true anemia?

Answer: Vein of Galen malformation

A vein of Galen malformation creates a large arteriovenous shunt, producing high-output cardiac failure and elevated MCA-PSV without true anemia.