[10] CHAPTER IV LESSON 2 Flashcards
A. MANAGEMENT OF THE FETUS
- Fetal Ultrasound
- Invasive Monitoring—Cordocentesis and Amniocentesis
- Intrauterine Transfusion
B. MANAGEMENT OF THE INFANT
- Cord Blood Testing
- Exchange Transfusion
- Simple Transfusions
- Phototherapy
- Intravenous Immune Globulin
- Cord Blood Testing
ABO Grouping
RhD Typing
Direct Antiglobulin Test
Elution
PREVENTION
- Selection of RBCs for Females
- Rh Immune Globulin
- Rh Immune Globulin
a. Dose and Administration
b. Maternal Weak D
c. Other considerations
At about (?), the clinical diagnosis of fetal anemia can be made using an ultrasound technique called
16 to 20 weeks’ gestation
fetal middle cerebral artery peak systolic velocity (MCA-PSV)
Readings are typically done every (?) to track the degree of fetal anemia; those that are greater than (?) multiples of the mean (MoM) are sensitive enough to predict significant fetal anemia in which intervention may be needed.
Fetal Ultrasound
2 weeks
1.5
Enhancement of blood flow, the umbilical vein is visualized at the level of the cord insertion into the placenta.
Invasive Monitoring—Cordocentesis and Amniocentesis
A spinal needle is inserted into the umbilical vein, and a sample of the fetal blood is obtained.
Invasive Monitoring—Cordocentesis and Amniocentesis
For risk stratification of fetal anemia, (?) to monitor amniotic fluid bilirubin levels has been replaced with MCA-PSV
Invasive Monitoring—Cordocentesis and Amniocentesis
amniocentesis
In the past, the concentration of (?) was used to estimate the extent of fetal hemolysis.
Invasive Monitoring—Cordocentesis and Amniocentesis
bilirubin pigment in the amniotic fluid
The amniotic fluid is tested by a (?) at 450 nm (the absorbance of bilirubin).
Invasive Monitoring—Cordocentesis and Amniocentesis
spectrophotometric scan optical density (∆OD)
The measurement is plotted on a graph (?) according to gestational age.
Invasive Monitoring—Cordocentesis and Amniocentesis
spectrophotometric scan optical density (∆OD)
Liley Curve Graph
An increasing or unchanging (?) as pregnancy proceeds predicts worsening of the hemolysis.
Invasive Monitoring—Cordocentesis and Amniocentesis
∆OD 450 nm
High values indicate severe and often life-threatening hemolysis (?) and require urgent intervention.
Invasive Monitoring—Cordocentesis and Amniocentesis
fetal hemoglobin less than 8 g/dL
is performed by accessing the fetal umbilical vein (cordocentesis) and injecting donor RBCs directly into the vein
Intrauterine transfusion
The goal is to maintain fetal hemoglobin above 10 g/dL.
Intrauterine Transfusion
Intrauterine Transfusion
Once initiated, the procedure is typically repeated every (?) until delivery to suppress fetal hematopoiesis.
2 to 4 weeks
The initial Intrauterine Transfusion is rarely performed after (?) gestation.
36 weeks’
Intervention in the form of intrauterine transfusion becomes necessary when one or more of the following conditions exists:
a. MCA-PSV indicates anemia (?).
b. [?] is noted on ultrasound examination.
c. Cordocentesis blood sample has hemoglobin level [?].
d. Amniotic fluid [?] results are high and/or increasing.
> 1.5 MoM
Fetal hydrops
less than 10 g/dL
∆OD 450 nm
Selection of RBC products for intrauterine transfusion
a. Group O
b. RhD-negative (or RhDpositive, depending on maternal blood group antibody)
c. Leukocyte reduced
d. Hemoglobin S negative
e. CMV-safe (CMV seronegative or leukocyte reduced)
f. Irradiated
g. Antigen-negative for maternal red blood cell antibody/antibodies
h. Hematocrit level greater than 70%
i. ABO antigens are not fully developed in newborn infants
ABO Grouping
ii. Infants do not have their own isohemagglutinins but may have those of the mother, so reverse grouping cannot be used to confirm the ABO group.
ABO Grouping
i. Rarely, the infant’s RBCs can be heavily antibodybound with (?), causing a false-negative Rh type, or what has been called (?)
RhD Typing
maternal anti-D
blocked Rh
ii. An eluate from these RBCs will reveal (?), and typing of the eluted RBCs will show reaction with (?).
RhD Typing
anti-D
anti-D
i. The most important serologic test for diagnosing HDFN is the [?] with (?).
Direct Antiglobulin Test
anti-IgG reagent
A positive test result indicates that there is antibody coating the infant’s RBCs
Direct Antiglobulin Test
however, the strength of the reaction does not correlate well with the severity of the HDFN.
Direct Antiglobulin Test
i. The preparation of an eluate may be helpful when the cause of HDFN is in question or suspected.
Elution
is the use of whole blood or equivalent to replace the neonate’s circulating blood and simultaneously remove maternal antibodies and bilirubin.
Exchange Transfusion
RBC units less than (?) from collection from the donor are selected to reduce the risk of (?).
Exchange Transfusion
7 to 10 days
hyperkalemia
After a (?) exchange transfusion, approximately (?) of the red blood cells have been replaced and (?) of the bilirubin has been removed.
Exchange Transfusion
two-volume
90%
50%
After the procedure, a platelet count should be performed to monitor for (?).
Exchange Transfusion
iatrogenic thrombocytopenia
The infant may receive small-volume or (?) RBC transfusions to correct anemia anytime from after birth to many weeks later.
Simple Transfusions
“top-off”
Many hospitals will keep (?) dedicated to an infant with HDFN and draw small aliquots from the parent RBC unit over time to decrease donor exposure over multiple transfusion episodes.
Simple Transfusions
1 unit
is used to metabolize the unconjugated bilirubin to isomers that are less lipophilic, less toxic to the brain, and able to be excreted through urine.
Phototherapy at 460 to 490 nm
is used to treat hyperbilirubinemia of the newborn caused by HDFN.
Intravenous immune globulin (IVIG)
competes with the mother’s antibodies for the Fc receptors on the macrophages in the infant’s spleen, reducing the amount of hemolysis.
Intravenous immune globulin (IVIG)
First pregnancy can be affected ABO
Yes
First pregnancy can be affected RhD
Rare
Disease predicted by titers ABO
No
Disease predicted by titers RhD
Yes
Causative antibody IgG ABO
Yes (AntiA,B)
Causative antibody IgG RhD
Yes (AntiD, etc)
Bilirubin level at birth ABO
Normal range