1. Fetal Dopplers- A Review
Kemoria Granberry DO

3. Types of Dopplers Arterial Venous Umbilical Middle Cerebral Uterine
Ductus venosus

4. Umbilical Artery Fetal-placental unit Progression Measurements
DecreasedAbsentReversed
Measurements
S/D(Systolic to Diastolic) Ratio
PI (Pulsatility Index)
Uniformity
Waveforms vary along length of cord
Absence of fetal breathing
Uniform waveforms
Direct assessment of the fetal placental unit
Remember the umbilical artery is derivative of common iliac without any somatic branch will give pretty accurate measure of placental perfusion
Question: If someone has absent end diastolic flow, how is the S/D ration calculated? YOU CANT, USE THE PULSATILITY INDEX INSTEAD!!
Close to placental insertion site downstream resistance to high velocity
Close to abdominal insertion site

5. Characteristics of Umbilical Artery waveform

6. Middle Cerebral Artery
Why the MCA?
Progression
Increased EDFV
Decreased PI
Measurement
Peak Systolic Velocity
Pulsatility Index
Cerebro-placental ratio
PEAK SYSTOLIC VELOCITY
Why the MCA?
-80% of cerebral blood flow
-most accesable of cerebral vessels
Pathology  in chronic fetal hypoxemia, there is centrally sparing effects that causes preferential blood flow to brain and adrenals, with decreased peripheral blood flow

7. Characteristics of MCA waveform

8. Ductus Venosus Physiologic status of right ventricle Progression
Decreased Absent Reversed flow in a wave
Measurement
Uniformity?

9. Characteristics of DV waveform
-biphasic

10. Uterine Artery Progressive decrease in impedence throughout pregnancy
Abnormal trophblastic invasion
Measurement
Notch PI
May reflect abnormal trophoblastic invasion if abnormal waveform

12. Q1: Should doppler ultrasound assessment be performed in low risk and/or high risk pregnancies as screening test for IUGR?
Why is this an important question to ask?
- If dopplers have been shown to predict fetal acidemia/stillbirth early detection may improve outcomes…ie BTMZ, early delivery, increased frequency of antenatal testing

13. Q1 Umbilical dopplers Uterine dopplers No Goffinet et al Chien et al
Meta analysis 1997
4 trials; n 11,275
Trials to date underpowered to determine utility of screening
Uterine dopplers
Chien et al
Meta analysis
28 trials ; n=3000
Abnormal result more likely to predict IUGR (liklihood ratio)
Cnossen et al
61 trials; n= 41000
Abnormal results corelated more with high risk pregnancies, though liklihood ratio remain high in low risk pregnancies as well
Conclusions  while these may be good tools they currently not standard of care because of lack of strong evidence, subjectivity of results (uterine art), age of surveillence.

14. Q2: What are the benefits and limitations of doppler studies of each vessel when IUGR is suspected?

15. Q2 Umbilical Doppler Middle Cerebral Dopplers Venous Dopplers
Significant reductions in IOL, CS, perinatal deaths
No validated interventions
Middle Cerebral Dopplers
May identify IUGR fetuses at risk for CS for NRFHT and neonatal acidosis
May identify IUGR fetuses at risk for long term neurodevelopment delay in presence of normal umbilical dopplers
Venous Dopplers
Identifies severely compromised IUGR fetus
No validated interventions shown that improve outcomes

17. Q3: What is the usual progression of doppler abnormalities in fetuses with suspected IUGR? Is this progression consistant/reliable?

18. Q3. Early – Brain sparing Late – Heart Sparing
Inc impedence in UA
Dec impedence in MCA
MCA normalization
Late – Heart Sparing
Inc flow through DV  improve left ventricular output
Increased Absent Reversed DV
Increased central venous pressure
Umbilical venous pulsations
Validated in preterm idiopathic IUGR fetuses
Changes can be variable, but there are some fairly predictable changes noted in setting hypoxemia
Early – Brain sparing
-preferenctial shunting of blood away from splanchnic circulation and to fetal heart/brains,/adrenal
-think of MCA normalization similar to normalization of ABG in status asthmaticus when organism losing ability to adapt
AS PLACENTAL DISEASE WORSENS AND MORE PLACENTAL VESSELS BECOME OBLITERATED LATE CHANGES OCCURS
Late – Heart sparing
-blood shunted via ductus venosus to left ventricle at the expense of fetal liver
-the increased right ventricle afterload improves left ventricular outflow….but eventually cardiac compliance plus inc end diastolic pressure leads to ominous chnages in DV

19. Q4: What dopplers study regimen should be initiated for suspected IUGR
Q4: What dopplers study regimen should be initiated for suspected IUGR? What other antepartum testing may be helpful in this setting?

20. Q4. Initiate Frequency Other testing Viability
Suspected IUGR – differentiate hypoxic growth restricted fetus from non hypoxic small fetus
Frequency
Weekly, q 2-4 weeks, 3-4x’s a week
Determined by severity of doppler abnormality
Other testing
Twice weekly NST with weekly AFI
Weekly BPPs
GOAL – REDUCE PERINATAL MORBIDITY/MORTALITY AND LIMIT UNNECCESSARY INTERVENTIONS
Remember that few things actually improve perinatal outcomes BTMZ, latency abx, and ANT..including dopplers

21. What interventions are available and should be considered based on abnormal fetal doppler velocimetry studies?

22. Q5.
Interventions
BTMZ
Hospitalization
Timing of delivery
ANT