umblical doppler variation _ fetus effect

Doppler study

1. ANTENATAL SCREENING 1.BASIC DOPPLER PRINCIPLES 2.UMBILICAL ARTERY DOPPLER 3. UTERINE ARTERY DOPPLER 4.MCA DOPPLER 5.DUCTUS VENOSUS DOPPLER

2. ARTERIAL WAVE FORM

3. VENOUS WAVE FORM

4. S/D RATIO RI- RESSISTANCE INDEX PULSATILITY INDEX- MAX HD INFORMATION VALUES DOES’T CHANGE SIGNIFICANTLY WITH CHANGE IN ANGLES NOTE- IDEAL ANGLE 0 DEGREE IS CONSIDERED ANGLE INDEPENDENT DOPPLER INDICES

5. BRANCH OF INTERNAL ILIAC ARTERY WHY ? 1 st trimester – Screen for early onset preeclampsia . 2 nd & 3 rd trimester : Assessement of suspected IUGR Time- Done at 20 weeks gestation – if abnormal repeat at 24 weeks UTERINE ARTERY DOPPLER

6. IN NON PREG UTERUS- HIGH RESISTANCE WITH LOW DIASTOLIC FLOW EARLY DIASTOLIC NOTCHING IN PREGNANCY- AS THE GESTATIONAL AGE INCREASES , THERE IS INCREASE IN DIASTOLIC FLOW IF THERE IS PLACENTAL INSUFFICIENCY , THERE IS REDUCTION IN FORWARD FLOW AT THE START OF DIASTOLE - KNOWN AS DIASTOLIC NOTCH DIASTOLIC NOTCH IS NORMAL IN NON PREGNANT AND DURING 1 ST TRIMESTER NOTCHING AFTER 24 WEEKS IS ABNORMAL – FETAL GROWTH RESTRICTION MATERNAL PREECLAMPSIA AND INCREASED RISK OF PRE TERM LABOR

7. PI – ABNORMAL > 95 TH PERCENTILE B/L NOTCHING AFTER 24 WEEKS PREDECT FGR/ PREECLAMPSIA PI

8. ARISE FROM THE INTERNAL ILIAC ARTERY OF THE FETUS. CARRY DEOXYGENATED FETAL BLOOD TO THE PLACENTA OXEGENATED BLOOD RETURNS FROM THE PLACENTA BY UMBILICAL VEIN. UMBILICAL ARTERY DOPPLER

9. DONE AT 24 WEEKS BUT IN TTTS IS SUSPECTED , THEN DONE REGARDLESS OF GA - WHY? IF THERE IS RSK OF FGR OR POOR PERINATAL OUTCOME STAGING OF TWIN – TWIN TRANSFUSION SYNDROME UMBILICAL ARTERY DOPPLER – WHEN / WHY

10. DONE WHEN FETUS IS AT REST / NOT BREATHING ( APNEA ) RESISTANCE IN PLACENTA DECREASES WITH ADVANCING GESTATION NORMALLY , DIASTOLIC FLOW NOT DETECTED IN THE FIRST 10 WEEKS- D/T INCOMPLETE VILLOUS MATURATION . CAN BE DETECTED BY ABOUT 15 WEEKS OF GESTATION

11. NORMAL UMBILICAL ARTERY DOPPLER

12. UMBILICAL ARTERY DOPPLER

13. Can be done as early as 18 weeks Normal MCA artery- high resistance flow -means there is minimal antegrade flow in fetal diastole . Normal Fetal MCA systolic/ diastolic ( S/ D) ratio must be higher than S/D ratio of umbilical artery Cerebroplacental ratio(CPR )>1:1 CPR- PI (MCA)/ PI ( UA ) PI decreases over time. Fetal MCA is used to asses – fetal cardiovascular distress, fetal anemia or fetal hypoxia . >1.5 MoM (multiples of median for GA )- fetal anemia MIDDLE CEREBRAL ARTERY DOPPLER

14. MCA DOPPLER CAN BE DONE- AS EARLY AS 18 WEEKS Used for additional work up of IUGR TTTS TWIN ANEMIA POLYCYTHEMIA SEQUENCE (TAPS) In pathological states – there is low resistance flow mainly as a result of fetal head sparing theory . Paradoxically , with severe cerebral edema – flow can return to high resistance pattern – very poor prognosis Occasionally end diastolic flow reversal , a non pathological finding , d/t to increased ICP d/t probe compression . ABNORMAL MCA DOPPLER

15. It is a sign of ASSYMETRICAL IUGR Normal HC, decreased abdominal circumference – d/t preferential supply of blood to cerebral , coronary, adrenal, & splenic circulation. In situations of CHRONIC FETAL HYPOXIA – fetus redistributes its cardiac output to maximize the o2 supply to brain by Vasodilatation of the cerebral arteries ,thereby causing decrease in LV AFTERLOAD . FETAL HEAD SPARING THEORY

16. MCA DOPPLER – B RAIN SPARING EFFECT

17. RECALL

18. VESSELS PI RI UMBILICAL ARTERY EARLY 2ND TRIMESTER(1.5-2) TERM-1(1-11.5 ) <0.7 MCA UTERINE ARTERY AT 28-32WKS(>1.45 ) TERM-1 18-22 WKS(<1.2) IF PI >1.45, B/L NOTCHING –SEVERE ISCHAEMIA 0.7-0.9 0.33-0.55 PULSATILITY INDEX AND RESISTIVITY INDEX COMPARISION

19. DV – Connection b/w umbilical vein & IVC Carries oxygenated blood returning from the placenta directly into RA WHEN - B/W-10 & 14 WEEKS GESTATION: To screen for aneuploidy . In combination with Nuchal translucency 2 nd and 3 rd trimester- suspecting IUGR Assessment of fetal cardiac function. DUCTUS VENOSUS DOPPLER

20. TRIPHASIC WAVEFORM – Characteristic sound of washing machine . S – WAVE – HIGHEST PEAK- ventricular systole D WAVE- SECOND HIGHEST PEAK- Early diastoe A WAVE- LOWEST PT- ATRIAL CONTRACTION

21. ABNORMAL

22. Reversal of “a ” wave

23. Reversal of a wave – fetal hypoxia