Flashcards in Hematology Deck (136)
What is the effect of ABO and Rh incompatibility?
Rh incompatability may be protective; as it destroys the fetal cells before the MOB can mount an immune response
What is the effect of an Rh negative mother and a Rh positive fetus?
if the mother is Rh negative and fetus is positive, there is a transplacental hemorrhage and the MOB will produce anti-D (resulting in fetal hemolysis)
What are the minor group incompatibilities?
- other Rh antigens (c, E) are most common
- Kell (K and k), infrequent; "kell kills"
- Duffy; "duffy dies"
- Lewis; "Lewis lives"
What are the associated risks with an exchange transfusion?
1) blood hypersensitivity
2) multiple donor exposure
3) umbilical line
7) air embolism
What is the expected volume of blood in a newborn?
80-100mL/kg; term infants are closer to 80, PT closer to 100
What are the indicated treatments for severe hemolytic disease?
- ABO: IVIG (reduces need for exchange transfusion)
- Exchange transfusion
What type of blood is ordered to complete an exchange transfusion?
whole blood; request hct ~ 55%
What is the effect of citrated blood that is used in an exchange transfusion?
decreased Ca levels; entire clotting cascade is Ca dependent
What orders are indicated s/p exchange?
bili, hct, plt, maybe Rx levels
- NPO for awhile
- monitor lab work Q6h
- may require a second exchange
What is physiologic anemia?
occurs in every baby; there is a large RBC mass at birth (r/t relative hypoxic intrauterine environment). At birth and with first breathes, increases PaO2, erythropoiesis ceases (for a period of time bc it is not needed); fetal RBCs have a shorter life span
What is the physiologic nadir of a FT infant?
nadir to hgb of 9-12; 10-12 weeks
What is the physiologic nadir of a PT infant?
nadir hgb is 7-8; presents much earlier
What is one of the most limiting nutritional factors in the making of new RBCs?
What are the causes of anemia of prematurity?
physiologic anemia processes, iatrogenic blood loss, disease, nutritional state, fetal-neonatal erythropoiesis
What are the physiologic contributors to anemia of prematurity?
1) low set point of O2 sensor (liver to kidney switch)
2) rapid body growth
3) shortened RBC span
4) Left shifted ODC at birth
5) low plasma EPO levels
6) cardiovascular factors: systemic and local
What are the non-physiologic contributors to anemia of prematurity?
1) laboratory blood loss
2) inadequate nutrient intake: protein, vitamins and calories
3) non laboratory blood loss and hemorrhage
What is the indicated treatment of anemia of prematurity?
1) minimize blood draws
2) good nutrition (protein & Fe)
What do RBCs of anemia of prematurity look like?
- normocytic ( normal size RBC)
- normochromic (RBC hgb concentration)
- hyporegenerative (stunted erythropoietin response)
What is the effect of Epo on anemia of prematurity look like?
- won't limit early treatment, may limit later transfusion needs
- no proof that you'll improve your outcomes (might just delay nadir
- may improve hgb
What is the reticulocyte count?
a measure of how quickly RBCs are being produced
How is reticulocyte count calculated?
% of RBCs in blood that are reticulocytes (# of retic divided by total hct) x 100
What are normal ranges for newborn reticulocyte count?
2.5%- 6.5% at birth, should fall by 2 weeks to 0.5%-2%
How can a reticulocyte count be helpful diagnostically?
can be used acutely in a baby that has hemolysis of chronic cases of anemia (have been retic-ing for awhile; and then production ceased in response to an O2 rich environment)
How should anemia be treated?
* biggest concern is delivery of oxygen to the tissues
treatment is based on infant's volume status
What is the treatment for anemia in a newborn that is hypovolemic?
acute blood loss has occurred; give volume expanders for a temporary fix (10-20mg/kg of volume)
What is the treatment for anemia in a newborn that is euvolemic?
occurs with chronic blood loss; simple PRBC transfusion only when symptomatic
What is the treatment for anemia in a newborn that is hypervolemic?
occurs with anemia and hydrops; isovolemic PRBC exchange
What are the clinical manifestations of acute and severe anemia during the intrauterine period?
1) decreasing fetal movement, sinusoidal FHR pattern
2) if chronically anemic > hepatospleenomegaly
What are the clinical manifestations of acute and severe anemia during the postnatal period?