Pediatric Transfusion Flashcards
How does hydrops fetalis occur?
Fetal anemia suppresses production of albumin, in turn causing high output heart failure.
Why isn’t kernicterus of concern before delivery?
Fetal bilirubin is eliminated by the mother.
How does fetal doppler ultrasound influence need to transfuse?
1.5x MoM indicates severe anemia requiring transfusion
What product requirements are applied to units for intrauterine transfusion?
Fresh, irradiated, washed, CMV-seronegative, HbS-negative, O-neg (OR MATERNAL) red cells that are crossmatch compatible with maternal plasma.
What is the sensitivity of the rosette test?
Detects any fetomaternal hemorrhage greater than or equal to 10mL.
What is the risk of maternal anti-D alloimmunization with, and without, RhIG?
16% without
0.1% with
How is are weak D and anti-G managed in the prenatal setting?
Both may not necessarily require RhIG, but just give it anyway.
How can RhIg be distinguished from true maternal anti-D?
Titers rarely exceed 4
No IgM component should be present (try to react with DTT)
What is the cause of FNAIT?
80% of cases from HPA-1a antibodies
10% of cases from HPA-5b
Others: HPA-4b (asian), 1b, 3a…
How severe is FNAIT? How is it treated
Quite severe. Develops fast and can often cause ICH. Treat with maternal IVIG, and IUT (plt, goal 50k for vaginal delivery).
What causes maternal thrombocytopenia? How should it be managed?
Most cases are dilutional, but 4% are immunologic (eg. ITP). Transfuse mother to 50k for vaginal delivery, 80k for epidural/caesarian. Don’t worry about the kid in cases of ITP.
What drives anemia of infancy?
Depression of EPO expression by the fetal liver which is habituated to the in utero hypoxic environment.
In which children do AABB standards allow waiving of the second ABO/Rh and antibody screen?
Children under 4mo of age (insignificant expression of isohemagglutinins)
What are the toxic effects of blood transfusion which can primarily affect neonates?
Hypothermia Citrate toxicity (incl. acidosis) Excess 2,3-DPG (avoid by using fresh blood)
What are the advantages of using syringes for pediatric aliquoting?
More accurate volume measurements, and use of in-line filters.
ARIPI
Trial which suggests no benefit to using fresh blood in VLBWs.
How much of a baby’s RBCs and bilirubin does a double-volume blood exchange remove?
~80% of fetal RBCs
~50% of bilirubin
What is the ideal product to be used in neonatal whole blood exchange?
Compatible pRBCs suspended in compatible FFP, reconstituted to baby’s hematocrit, and ideally also CMV/HbS neg with other special preps….
What is the bilirubin cutoff for whole blood exchange? How long does it take to do a 2x blood volume exchange?
> 25mg/dL
Takes 90-120min to complete (do not transfuse faster than 5mL/kg/5min).
What is a typical dose of red cells, plasma, and platelets in infants? Cryo?
RBCs: 10mL/kg
Plasma: 10-15mL/kg
Platelets: 5-10mL/kg
Cryo: No more than 1 unit.
What can cause neonatal polycythemia, and how is it managed?
Maternal diabetes
Can be managed by exchange with blood reconstituted to the proper hematocrit.
What is the association between necrotizing enterocolitis and blood transfusion?
Previously thought to be associated in some causative fashion, but now thought to be confounded by severe anemia.
What are some transfusion goals in sickle cell disease? In thalassemia?
SCD: Target Hb 8-9g/dL with HbS <30%.
Thalassemia: Target Hb 8-10g/dL, manage iron overload.
What causes anemia of infancy/prematurity?
Decrease in EPO expression (normally accustomed to relatively hypoxic in utero conditions). Also phlebotomy.
What is the benefit of a 2x volume exchange transfusion?
Removes 90% of abnormal RBCs, 50% of bilirubin.
How should crossmatching be done in neonatal settings?
May crossmatch against maternal plasma sample.
What are some transfusion thresholds in the first 3 weeks of life?
Week 1: 10g/dL (more if respiratory support needed)
Week 2: 8.5g/dL (more etc)
Week 3: 7.5 g/dL
What is the benefit vs cost of delayed cord clamping?
Delayed cord clamping increases red cell mass and immune response and reduces coagulopathy. However, can cause hyperviscosity and more bilirubin load.
How does the rate of adverse reactions to transfusion in children compare to adults?
Children have slightly more reaction rates overall, especially allergic reactions.
What are some typical RBC transfusion thresholds in children?
<7g/dL in general
<8g/dL perioperative or on chemo
Hct < 35% on ECMO or with severe pulm dz
What are some typical PLT transfusion thresholds in children and neonates?
<25k for neonates (even higher if VLBW/ELBW)
<80k for bypass and ECMO
Neonatal purpura fulminans
Thrombotic disorder with skin necrosis caused by congenital factor C/S deficiency. Treat with plasma ASAP.
What effect does use of INTERCEPT technology have on phototherapy?
None; the psoralen should be fully removed and even if not the wavelengths are non-overlapping.
What are the consequences of underdeveloped immune response in neonatal transfusion?
Less likely to form red cell antibodies
Less able to tolerate CMV transmission, TA-GVHD.
What are the consequences of small neonatal blood volumes in transfusion?
Transfusions are relatively large; be mindful of minor incompatibility, of storage lesions, and of phlebotomy. Use aliquots.
