TOG - clinical application of doppler ultrasound in obstetrics - 2014 Flashcards
An abnormal UA doppler waveform has been demonstrated to predict fetal compromise. How many days before acute fetal deterioration may this pattern present.
12 days
How might umbilical artery velocimetry improve perinatal outcome in high risk pregnancies?
Due to the avoidance of iatrogenic preterm delivery as clinicians had more information on fetal wellbeing to time delivery more optimally.
In a SGA fetus less than 32 weeks gestation with absent or reversed EDF, what changes might prompt delivery before 32 weeks?
When the ductus venous becomes abnormal or there are UV pulsations
What is the classical temporal sequence of progressive doppler abnormalities in the growth restricted fetus?
Umbilical artery doppler >95th centile,
Cerebroplacental ratio or MCA PI <5th centile,
Absent EDF,
Reversed EDF umbilical artery,
Aortic isthmus and ductus venosus PI >95th centile
Absent or reversed A-Wave ductus venosus
Pulsatile umbilical vein
CTG and biophysical profile abnormalities
Fetal acidaemia and stillbirth
What is the controversy with the classical temporal sequence of progressive doppler abnormalities?
Although the recognised sequence of deterioration of UA to MCA to DV does exist, it does not exist more frequently than any other pattern.
The reason for such variance is unclear.
Lack of RCT trials
At what value is the MCA PSV predictive of fetal anaemia
MCA PSV greater than 1.5 multiples of the median (MoM) is predictive of fetal anaemia
what is the “brain-sparing” effect?
in FGR - there is preferential shunting to the cerebral cortex, leading to increased diastolic flow and hence reduction in PI
What is the cerebroplacental ratio
the MCAPI/UA PI ratio.
It has a greater sensitivity than assessing the MCA or UA doppler PIs in isolation
A low or abnormal result associated with adverse perinatal outcome.
