Fetal ductus venosus flow assessment
Updates to Article Attributes
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was changed:
Fetal ductus venosus flow assessment can be sonographically assessed in a number of situations in fetal ultrasound:
- first-trimester screening for aneuploidic anomalies
- second-trimester scanning when there are concerns regarding
Of all the pre-cardial veins, the ductus venosus allows the most accurate interpretation of fetal cardiac function as well as myocardial haemodynamics 9.
Radiographic assessment
Ultrasound
Technique
- the fetus should be as still as possible
- the probe is ideally focused so sampling is done where the umbilical vein joins the ductus venosus
- a right ventral mid-sagittal view of the fetal trunk should be obtained and colour flow mapping used to demonstrate the umbilical vein, ductus venosus and fetal heart
- the probe is ideally angled to allow a mid sagittal plane or a transverse oblique plane through the fetal abdomen
- the image should be magnified enough for the fetal thorax and abdomen to occupy the whole screen
- do not contaminate the ductus venosus flow with the flow from the fetal inferior vena cava, for this the Doppler sample should be small (0.5-1 mm)
- the insonation angle should be 30°
- the sweep speed should be high (2–3 cm/s) so that the waveforms are spread allowing better assessment of the A-wave
On Doppler ultrasound, the flow in the ductus venosus has a characteristic triphasic waveform where in a normal physiological situation flow should always be in the forward direction 7 (i.e. towards the fetal heart).
This triphasic waveform comprises of:
- S wave: corresponds to fetal ventricular systolic contraction and is the highest peak
- D wave: corresponds to fetal early ventricular diastole and is the second highest peak
- A wave: corresponds to fetal atrial contraction and is the lowest point in the wave form albeit still being in the forward direction
See also
-<li>the probe is ideally focused so sampling is done where the umbilical vein joins the ductus venosus </li>- +<li>the probe is ideally focused so sampling is done where the <a title="Umbilical vein" href="/articles/umbilical-vein">umbilical vein</a> joins the <a title="Ductus venosus" href="/articles/ductus-venosus">ductus venosus</a>
- +</li>
-<li>do not contaminate the ductus venosus flow with the flow from the fetal inferior vena cava, for this the Doppler sample should be small (0.5-1 mm)</li>- +<li>do not contaminate the ductus venosus flow with the flow from the fetal <a title="Inferior vena cava" href="/articles/inferior-vena-cava-1">inferior vena cava</a>, for this the Doppler sample should be small (0.5-1 mm)</li>