Neonatal and intrauterine transfusions Flashcards Preview

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Flashcards in Neonatal and intrauterine transfusions Deck (13)
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1

Red cells for intrauterine or neonatal exchange transfusion

  • fresh (<5 days old); if not available consider washed
  • irradiated
  • group O
  • negative for maternal antibody that is active
  • preferably serologically tested CMV negative or CMV risk reduced (leukoreduced) in intrauterine transfusion or neonate <1200 g who are CMV negative
  • 15 ml/kg

2

Plasma or plasma containing products for neonates/intrauterine

  • must be compatible with neonates RBCs
  • FFP given at 10 ml/kg
  • platelets given at 5 ml/kg
  • cryoprecipitate given at 10-20 ml/kg

3

maternal immune thrombocytopenic purpura

  • risk of neonatal thrombocytopenia
    • caused by autoantibodies that cross the placenta
    • may be complicated by severe neonatal thrombocytopenia (<50,000) and serious hemorrhage
  • management
    • supportive platelet transfusions are sparingly given, typically with active bleeding
    • monitor serial platelet counts for a few days after delivery

4

Cause of NAIT

Recurrence rate of NAIT

  • Most commonly caused by maternal alloantibodies directed against HPA-1a
    • 2% of individuals are HPA-1a negative
    • can develop anti HPA-1a antibodies if exposed through transfusion or pregnancy
  • likelihood of recurrence in subsequent pregnancy is high
  • NAIT can affect the first pregnancy
  • more severe with each successive pregnancy

5

Management of NAIT

  • 20% incidence of intracranial hemorrhage overall; about half of hemorrhages occur in utero
  • treatment should begin as soon as the diagnosis is suspected
  • high dose IVIg and/or corticosteroids
  • Intrauterine platelet transfusion may begin at 18-20 weeks gestation, with antigen negative platelets
  • maternal platelets may be used if they have been washed and irradiated
  • delivery by C section is recommended
  • After birth the risk of hemorrhage is greatest during the first 24-36 hours of life, so expedient platelet transfusion is a good idea

6

HDFN

  • Results from maternal alloantibodies crossing placenta 
  • can lead to appearance of bilirubin in the amniotic fluid, progressive fetal anemia and eventual hydrops fetalis
  • to be significant the maternal alloantibody must be IgG1, IgG3, or IgG4

7

Rh HDFN causes

caused by maternal anti D antibodies

  • mom must have prior exposure to D+ RBCs; sources:
    • prior pregnancy
    • chorionic villus sampling
    • amniocentesis
    • cordocentesis
    • abortion, threatened or complicated
    • placental abruption
    • trauma

8

Prevention of Rh HDFN

  • Check pregnant woman's D status and check D- women for antibodies
  • D negative women without antibodies: prophylactic globulin RhIg) given at intervals and whenever a fetal maternal hemorrhage occurs
  • D negative women with anti D antibodies: determine titer
    • if titer < 16 then severe hemolysis is unlikely
    • if titer is at least 16, monitor degree of fetal hemolysis with either
      • amniotic fluid sampling with plotting of OD450 on Liley curve
      • noninvasive Doppler US measurements of MCA flow

9

Tests for fetomaternal hemorrhage

  • Rosette test (qualitative)
    • maternal blood is incubated with anti D antibody and D+ indicator cells, which form rosettes around D+ fetal cells
    • will detect 10 ml of fetal blood
    • if this test is negative and FMH is still suspected then 300 ug dose of RhIg is given
    • if positive then a quantitative test (KB, ELAT, or flow) is done
  • Kleihauer-Betke (acid elution)
    • HbF is resistant to acid elution
    • maternal blood is subjected to acid elution then eosin stained; any cells that take up stain (rather than appearing as ghosts) represent cells containg HbF
    • a cell count is performed to determine the percentage of fetal red cells

10

Treatment for D negative woman bearing D+ or D unknown baby

  • Prophylactic 300 ug (1 full dose vial) at 28 weeks and again at term
  • without RhIg the risk of developing anti D is 16%; with RhIg as above the risk is 0.1%
  • FMH 
    • in first 12 weeks give minidose (50 ug) or a full dose (300 ug)
    • After 12 weeks, a full dose is given
    • additional doses given as needed

11

Calculating the dose of RhIg

  • assume maternal blood volume is 5000 ml (otherwise volume = weight x 70 ml/kg)
  • determine proportion of fetal cells by KB or other test (count 2000 cells)
  • Dose (vials) = maternal blood volume (ml) x proportion of fetal cells in maternal blood / 30
  • divide by 30 because each vial protects against 30 ml of whole blood or 15 ml of RBCs
  • always add 1 vial to dosage (e.g., 3.3 needs 4 vials and 3.6 needs 5 vials)
  • no more than 5 vials should be given IM at one time; larger doses may be divided or given IV

12

Non-Rh HDFN

  • due to ABO is most common type
    • clinically mild
    • seen in blood group O moms with A or B fetus
    • mediated by IgG and anti A, B antibody
    • may affect first pregnancy
  • HDFN due to Kell is most common cause of severe HDFN
    • K is expressed early in RBC maturation thus there is destruction of marrow precursors as well as circulating RBCs
    • a maternal critical titer for anti Kell antibody is 8
  • Anti C is second most common cause of severe HDFN

13

Lab testing for HDFN

  • type and screen on maternal blood 
  • cord blood from newborn subjected to ABO/Rh typing and DAT, including Rh testing for weak D since weak D fetal RBCs can sensitize D negative moms
  • If cord blood DAT is positive
    • and maternal antibody screen is positive, then identity of maternal antibody is determined by red cell panel
    • if maternal antibody screen is negative, then there are multiple possibilities:
      • ABO HDFN
      • prior to RhIg administration
      • fetal low incidence antigens that are not present on the screen cells (may need extended panel)
    • next check neonatal bilirubin serially