Management of  Rh-Sensitized Pregnant Patient
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Management of Rh-Sensitized Pregnant Patient

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Management of

Management of
Rh-Sensitized Pregnant Patient

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Management of  Rh-Sensitized Pregnant Patient Management of Rh-Sensitized Pregnant Patient Presentation Transcript

  • Management of Rh-Sensitized Pregnant Patient Prof. Aboubakr Elnashar Benha University Hospital. Egypt Aboubakr Elnashar
  • Any Rh- patient with an anti-D titer >1:4 should be considered sensitized. 1. Sonogram. At 1st visit Accurate dating for G age {interpret fetal tests timing of fetal interventions}. Aboubakr Elnashar
  • 2. Establish Paternal Blood Type. {The pregnancy is at risk only if the fetus has inherited the D antigen}. Paternal Ag: {avoid multiple fetal interventions}. Paternal red cell phenotype •If Rh-: the fetus will be Rh- and not at risk: No further intervention. •If heterozygous for D: the fetus has a 50% chance of being at risk. •If homozygous: the fetus will be at risk for hydrops. All fetuses must be assumed to be Rh+ until proven otherwise. Aboubakr Elnashar
  • 3. Follow Serial Maternal D Antibody Titer. Critical titer: The titer at which fetus is at risk 1:16 or An increase of >1 dilution (e.g. 1:2 to 1:8). Once the maternal antibodies surpass the critical titer: further titers will no longer be helpful serial fetal testing will be required throughout the remainder of the pregnancy. Correlation between titer and severity of disease: poor. But: significant hemolytic disease Elevated antibody titers at the beginning of pregnancy rapid rise in titer titer of 1 : 64 or greater, Aboubakr Elnashar
  • 4. Serial Fetal Assessment. Aim: Determine timing of intervention. a. Amniocentesis. Serial beginning at 24 to 26 w {determine the likelihood of fetal anemia}. Amniotic bilirubin 2ndry to fetal hemolysis was directly proportional to the spectrophotometric peak at 450 nm (OD450) (Liley, 1961). Aboubakr Elnashar
  • Zone 1: The fetus is unlikely to be affected at this time, or only mildly affected: repeat amniocentesis in 10 to 14 days. Zone 2: The fetus is experiencing mild-to-moderate hemolysis. lower zone (>80%): amniocentesis in 10 to 14 days upper zone(<80%): fetal blood sampling Zone 3: The fetus is anemic. A high probability of fetal death is present in 7 to 10 days unless intervention occurs: fetal blood sampling Aboubakr Elnashar
  • Fetal blood sampling (Hct<30%): <35 w: intrauterine transfusion >35 w: delivery Aboubakr Elnashar
  • b. Middle cerebral artery peak systolic velocity (MCA- PSV) The most significant breakthrough in the surveillance of the potentially anemic fetus Based on: In fetal anemia: Enhanced fetal cardiac output and Decrease in blood viscosity: Increased blood flow velocity preferentially shunt blood to brain faster most pronounced MCA PSV Aboubakr Elnashar
  • Frequency •Initiated: as early as 18 w •Repeated: every 1–2 w as the clinical situation warrants. Aboubakr Elnashar
  • Aboubakr Elnashar
  • Steps: A transverse view of the fetal brain is obtained at the level of BPD. The transducer is then moved caudally to demonstrate the thalamus clearly. With color flow imaging MCA can be identified as the major anterolateral branch of the Circle of Willis. The pulsed Doppler sample gate should be placed at the junction of the medial third and middle third of this artery Pulsed Doppler is then used to measure MCA-PCV just distal to its bifurcation from the internal carotid artery. The angle of insonation is invariably small due to the usual occipitotransverse position of the fetal head. Since the MCA-PSV is a measurement of absolute instead of relative velocity, the angle of the fetal Doppler insonation should be kept as close as possible to 0˚ for accurate estimate of the absolute peak systolic flow velocity. Aboubakr Elnashar
  •  Power Doppler with visualization of the Circle ofWillis and the Middle cerebral artery. Aboubakr Elnashar
  •  Normal flow of the MCA in 1- st trimester Aboubakr Elnashar
  •  Normal flow of the MCA in 2 and 3 trimester. Flow velocity wave form in the fetal MCA in a normal fetus Aboubakr Elnashar
  • Top. Color Doppler waveform obtained from the middle cerebral artery in a normally grown fetus at 34 weeks. Bottom. Measurements are obtained using the maximum frequency follower. Aboubakr Elnashar
  • Interpretation {MCA velocity increase with advancing gestational age} results are reported in MoM. The actual value can be plotted on standard curves or entered into a website that will calculate the MoM value (www.perinatology.com). A value greater than 1.5 MoM: moderate to severe f anemia: further investigation through direct ultrasound- guided fetal blood sampling (cordocentesis) After 35 w: false positive rate for the prediction of f anemia is increased {fetal heart rate accelerations} Aboubakr Elnashar
  • The solid curve indicates the median MCA-PSV The dotted curve indicates 1.5 multiples of the median. Aboubakr Elnashar
  • MCA-PSV plotted as a function of gestational age. Above the upper line (1.5 multiples of the median): invasive testing and treatment are indicated. Below that line, individual monitoring regimes are established. Aboubakr Elnashar
  • Aboubakr Elnashar
  • Top: Color Doppler waveform of the MCA. Bottom:The maximum frequency follower has been used to calculate the PSV (87.9cm).The value lies above the 95th centile for gestation, making it highly suggestive of fetal anemia. Aboubakr Elnashar
  • MCA waveforms in an anemic fetus requiring serial transfusions for severe Rh (D) disease. The peak systolic velocities of 62, 50, and 61 cm per second (top to bottom) corresponded to fetal hematocrits of 19%, 44%, and 32%, before, at the time of, and a week after the first intravascular transfusion, respectively. Aboubakr Elnashar
  • Advantage More sensitive for predicting f anemia than the ΔOD450 (Recent studies) Alternative to serial amniocenteses Excellent noninvasive tool for the monitoring of f anemia. Reduction of over 80% in the need for invasive diagnostic procedures such as amniocentesis and cordocentesis. Aboubakr Elnashar
  • An accurate predictor of severe f anemia (II-1A) (Recent systematic review) Correlation with the fetal hemoglobin value becomes more accurate as the severity of anemia increases The correlation between hemoglobin concentration and the MCA-PSV has rendered amniocentesis for the measurement of the ΔOD450 an outdated tool {transfusion therapy should never be initiated without confirming fetal anemia}. Aboubakr Elnashar
  • Limitations 1. Reliability decreases after 35 w, so alternative methods must be used. 2. Dopplers can easily be measured incorrectly: should be performed only by experienced clinicians. Aboubakr Elnashar
  • Flow velocity waveform in the fetal MCA in a severely anemic fetus at 22 w. blood velocity is increased Aboubakr Elnashar
  • Other sonographic findings have been claimed to either precede the development of hydrops or predict fetal anemia: amniotic fluid volume liver and spleen length or thickness placental thickness increased bowel echogenicity cardiac biventricular diameter none of these are reliable. Aboubakr Elnashar
  • 6. Serial NSTs or BPPs Weekly beginning at 32 W. Aboubakr Elnashar
  • 6. Delivery. At 35 weeks: 1. Fetus has required transfusion 2. Abnormal Doppler studies At 37 and 39 weeks: If the maternal critical titers were not reached Aboubakr Elnashar
  • Management of Sensitized Rh-Negative Women Serial indirect Coombs tests are performed at monthly intervals after 18 w until the critical titer is exceeded. • At that time, serial MCA-PSV are performed weekly. • Cordocentesis is performed when MCA-PSV>1.5 MoM During the first sensitized pregnancy, the Coombs titer correlates with the severity of fetal disease. However, these titers are poorly predictive after the first sensitized pregnancy. Aboubakr Elnashar
  • Thank you Aboubakr Elnashar