blood bank: perinatal and neonatal transfusion issues

what is perinatal

around the time of birth

what is neonate

newborn child from birth the 4 weeks of age

what is an infant

a child during the first year of life

what is gravid

number of times a woman has been pregnant

what is para

number of times a woman has delivered a live newborn

what is abortus

the number of times there was a miscarriage or abortion

what is antepartum

directly before the birth of the child

what is postpartum

directly after the birth of the child

what is prenatal

anytime from the beginning of pregnancy to before the birth of a baby

what happens each time a female is pregnant

there is a possibility she will be exposed to red cell antigens on fetal red cells that the fetus has inherited from the father

what is the main cause of HDFN

IgG antibodies from the mothers circulation cross the placenta and bind to antigens on fetal RBCs causing hemolysis of fetal blood

what is fetomaternal hemorrhage

when fetal RBCs enter the maternal circulation

in Rh factor incompatibility, the mother is Rh __ and the fetus is Rh __

negative, positive

does Rh blood incompatibility usually affect the first child?

no

most incompatibility is due to __ antibodies

ABO

in ABO incompatibility, can the first child suffer?

yes

you can suspect ABO incompatibility in all of the following except if

the mother has a positive antibody screen

an elution releases

maternal anti-A or anti-B antibodies from fetal RBCs

what is erythroblastosis fetalis

immature nucleated RBCs are pushed into fetal circulation

what therapy is used for bilirubinemia in newborns

phototherapy

what is kernicterus

when high levels of bilirubin affect the neurons in the brain, causing severe neurological damage

what blodo is used for neonatal exchange transfusion

CMV negative, fresh leukoreduced blood

ABO antibodies are type

IgG

anti-Kell (K) antibodies are considered

clinically significant

what can you conclude if the history shows the woman has had one child and she previously typed as AB positive with a negative antibody screen

mom has no naturally occurring antibodies and no unexpected antibodies, the baby is not at risk

what can you conclude if the woman has had one child and previously typed as O negative with a negative antibody screen and the child was O negative

mom has no anti-D, baby is not at risk

what if the woman previously typed as O negative with an anti-D antibody and had an A positive child

mom has anti-D and naturally occurring anti-A and anti-B, the baby is at risk due to the anti-D and anti-A attacking the baby’s A positive cells

if an antibody screen is positive, what is the next step

the antibody is identified

if the antibody screen on a Rh negative woman is anti-D, what is the next step

the antibody should be titered

if the antibody screen on a pregnant woman is negative and the woman is Rh negative, what is the next step

a second screen should be performed at 28 weeks

an IgM antibody

does not cause HDFN as it does not cross the placenta

a titer greater than ___ of IgG antibody is considered problematic

8

when would you perform a percutaneous umbilical blood sampling or cordocentesis

if there is serous risk of HDFN

what is doppler flow

using ultrasound to monitor the flow of blood through the middle cerebral artery (MCA) in the brain of the fetus

too fast of a doppler flow suggests

low HGB/HCT as the anemic blood is less viscous than normal fetal blood

how can plasma exchange of the mother treat HDFN

the antibodies causing the problem are temporarily removed from the mother’s circulation

what is an intrauterine transfusion (IUT)

a small syringe of irradiated O-negative RBCs lacking an antigen that is inserted to the umbilical cord

for an IUT to be successful and safe, it must also be

compatible with the mother’s serum

how do you prevent HDFN

by administering anti-D antibody (RhIg) before and after the birth of the child

how does RhIg theoretically work

it will quickly bind to any D-positive fetal cells that may enter the mother’s circulation, masking the fetal cells so that the mother’s immune system cannot recognize the D antigen

all cord blood that types RhD negative

should be tested for weak D

one dose of RhIg is enough to neutralize ___ of D positive packed red cells

15 ml

one dose of RhIg is enough to neutralize ___ of D positive whole blood

30 ml

a first dose is given to Rh negative mothers between

28 and 30 weeks gestation

a second dose of RhIg is given if the neonate is typed as

Rh positive

a second dose of RhIg is given within ___ of birth

72 hours

if the mother has a positive antibody screen postpartum, a titer greater than 4 indicates that

the mother was actively immunized

which test determines whether a mom needs RhIg

rosette test

which test can determine the number of doses of RhIg needed to prevent immunization

kleikauer-betke (KB) stain

rosette test procedure

Reagent IgG anti-D is added to a suspension of the mother’s red cells and is incubated

The antibody will bind to any D positive fetal cells present in the mom’s sample

The cells are washed to remove excess anti-D and a dilute solution of D-positive cells (“indicator cells”) is added

If there are any fetal cells present, the anti-D antibody that is bound to them will also bind the reagent D cells forming a clump of reagent cells around each fetal cell

5 or more rosettes in 5 fields indicates

more than one dose of RhIg is needed

the KB stain has an affinity for

fetal hemoglobin

what constant can be used to calculate the number of doses needed

1.67

how do you calculate the KB stain dosage amount

(% fetal cells times 1.67) + 1

DAT is performed on cord blood from all mothers that have a ___

positive antibody screen

if the newborn has a positive DAT and the mother has a negative antibody screen, the child’s red cells may be coated with

anti-A or anti-B, or antibody to low incidence antigen

normal bilirubin peak for newborns

5.0-6.0 mg/dl

if the newborn is suffering from anemia due to HDFN, what is done next

small transfusions of 10 to 15 ml of blood are done

if a newborn has persistently high bilirubin, what is done next

they are treated with phototherapy

why is only a forward type performed on neonates

there is normally no anti-A or anti-B in the baby’s immune system

the newborn will have the same ___ antibodies as the mother

IgG

the newborn will get ___ from the mother’s milk

IgA