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Radiology
Cordocentesis and Fetal Transfusion
Built from Obstetric Imaging
What’s inside
8 sections · 94 slides
Overview
- Definition of cordocentesis
- Topics covered
- Development of fetal blood sampling techniques
- Decline in the use of cordocentesis for prenatal diagnosis
Indications, Setting and Counselling
Who needs the procedure, where it should happen, and what the patient is told first
- Indications for cordocentesis
- Cordocentesis in prenatal genetic testing
- Setting for the procedure
- Preparation at a viable gestational age
- Counselling before the procedure
Fetal Anemia
The commonest reason for the procedure: what causes it, how it is found, and how transfusion is timed
- Definition of fetal anemia
- Consequences of untreated fetal anemia
- Two broad groups of cause
- Rhesus D sensitisation and its decline
- Red cell antigens other than D
- Nonimmune causes of fetal anemia
- Shift in the causes of hydrops fetalis
- Parvovirus infection and fetal anemia
- Colour Doppler of the fetal middle cerebral artery
- Middle cerebral artery Doppler screening
- Thresholds that trigger action
- Serial transfusions
- Loss of Doppler accuracy after transfusion
- Raising the Doppler threshold after transfusion
- Timing the next transfusion from the fall in haemoglobin
- 0.45 g/dL
- 13 days
Fetal and Neonatal Alloimmune Thrombocytopenia
Low fetal platelets from maternal antibodies, and how the role of cordocentesis has shrunk
- Fetal and neonatal alloimmune thrombocytopenia
- Platelet antigens involved
- Differences from red cell alloimmunisation
- Clinical spectrum of FNAIT
- When to suspect FNAIT
- Diagnosis of FNAIT
- Goal of FNAIT management
- Historical role of cordocentesis in FNAIT
- Current management of FNAIT
- Remaining role for fetal blood sampling in FNAIT
Contraindications and Risks
What weighs against the procedure, and the complications that follow it
- Contraindications to cordocentesis
- Maternal viral infection
- Early gestational age
- Conflicting data on very early sampling
- Risks of the procedure
- Overall balance of risk and benefit
- Fetal bradycardia
- Streaming from the puncture site
- Umbilical cord hematoma after cordocentesis
- Consequences of umbilical cord hematoma
- Emergency caesarean delivery after the procedure
- Fetal loss rates after cordocentesis
Technique
From the first survey scan to the last check of the puncture site
- Sequence of a sampling and transfusion procedure
- Preprocedure ultrasound survey
- Grayscale and colour Doppler view of a posterior cord insertion
- Reading the two panels
- Colour Doppler panel of the cord insertion
- Umbilical cord within the uterus
- Vessels of the umbilical cord
- Needle target sites
- Choosing the target site
- Needle route for an anterior and a posterior placenta
- Readiness to transfuse
- Skin preparation and sterile setup
- Needle choice for sampling and transfusion
- Advancing the needle into the umbilical vein
- Needle within the umbilical vein at the placental cord insertion
- Recognising the needle on ultrasound
- Handling the needle once it is in the vessel
- Immediate analysis of the sample
- Fetal paralysis
- Keeping the needle steady during transfusion
- Blood product used for intrauterine transfusion
- Factors determining the transfusion volume
- Needle within the fetal peritoneal cavity
- Intraperitoneal needle placement
- Finishing the procedure
- Monitoring after the procedure
Outcomes
Success rates, survival after transfusion, and what is known about later development
- Success rate of fetal blood sampling
- Obstetric complications compared with no sampling
- Survival after intrauterine transfusion
- Neurodevelopmental follow-up
- The LOTUS study
- 4.8%
- Severe hydrops and neurodevelopmental impairment
Key Points and References
The summary the chapter itself draws, and the sources behind it
- Key points: indications and sites
- Key points: fetal anemia
- Key points: alloimmune thrombocytopenia
- Suggested reading
- References
- References
- References
- References
- References
- References
- References
- References
- Obstetric Imaging: Fetal Diagnosis and Care, 2nd Edition