1 Doppler and IUGR Danny Wu, MBChB Clinical Instructor Division of Maternal Fetal Medicine Obstetrics, Gynecology and Reproductive Sciences UCSF Outline • Background of Doppler ultrasound • IUGR • Fetal cardiovascular changes by Doppler – Arterial • Umbilical artery • Middle Cerebral Artery – Venous • Ductus Venosus Physics of Doppler Ultrasound Doppler frequency shift v = fd.c / 2 ft.cos θ
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Doppler and IUGR • IUGR - UCSF CME€¦ · 1 Doppler and IUGR Danny Wu, MBChB Clinical Instructor Division of Maternal Fetal Medicine Obstetrics, Gynecology and Reproductive Sciences
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Doppler and IUGR
Danny Wu, MBChBClinical InstructorDivision of Maternal Fetal MedicineObstetrics, Gynecology and Reproductive SciencesUCSF
Outline
• Background of Doppler ultrasound• IUGR• Fetal cardiovascular changes by Doppler
Absent End Diastolic Flow Reversed End Diastolic Flow
Perinatal Outcomes
• Absent or reversed flow is associated with adverse perinatal outcome
• It may be present for weeks before additional sign of fetal compromise occurs
Doppler in High Risk Pregnancy
• Eleven RCTs involving nearly 7000 women were included
• Reduction in perinatal deaths (OR 0.71)• Fewer inductions of labor (OR 0.83)• Fewer admissions to hospital • No difference fetal distress in labor• No difference caesarean delivery
Cochrane Database Syst Rev. 2000;(2):CD000073
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Routine Doppler in Low Risk Pregnancy
• Not Recommended• Five trials were included which recruited
14,338 women
• No benefit
Cochrane Database Syst Rev. 2008
PhysiologicalChanges
Increased placental vascular resistance
Shunting to vital organs“Brain-sparing”
Impaired cardiacfunctions
UA S/D increases
MCA P/I decreases
Abnormal venous flow
Doppler Changes
MCA Doppler
Brain Sparing Effect
Cerebral Circulation“Brain Sparing Effect”
Cerebral Blood Flow
• Hypoxemia
• Hypoxemia + Acidemia
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MCA Doppler1. Fetus at rest2. Circle of Willis3. Zoom – MCA 50% of
screen4. Sample volume 1mm
placed between origin of carotid and the middle of the artery
5. Angle between USS and blood flow = 0°
6. Consistent waveforms7. Repeat 3 times
Doppler Waveform Analysis
Example of an MCA Doppler tracing at 27 weeksMiddle Cerebral Artery
IUGR
MCA PI PO2
MCA PI PO2 2 – 4 SD
MCA PI PO2 < 4 SD
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Mari et al Ultrasound Obstet Gynecol 2007; 29:310-316
Mari et al Ultrasound Obstet Gynecol 2007; 29:310-316
MCA - PI or - PSV?
• MCA - PSV predicts perinatal mortality more accurately than MCA - PI
• Reason:– MCA - PI tends to normalize before delivery
or demise– MCA - PSV tends to slightly decrease just
before delivery or demise BUT it remains elevated
Venous Dopplers
Reflects fetal cardiac functionPredictive of adverse perinatal outcome
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Ductus Venosus Qualitative Assessmnet
• Blood flow should always be antegrade
• Absent or reversed flow is alwaysabnormal
SD
A
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Semi-quantitative Assessment Outcomes related to Doppler changes
Baschat et al Ultrasound Obstet Gynecol 2006; 27: 41–47
Venous Doppler abnormalityis the strongest predictor