Blood transfusion Flashcards
What is blood transfusion?
It is transferring blood or blood-products (e.g. RBCs, or platelets or fresh frozen plasma) from one person into the circulatory system of another
When is blood transfusion used?
- Hemorrhage
- Major surgical operations
- Severe anemia
- Bleeding attacks (disturbance in clotting factors and platelets)
- Severe liver failure
- Erythroblasts fetalis
What tests need to be carried out before blood transfusions?
Donor:
* Determine blood group (OAB and Rh)
* Microbiological tests (Human Immunodeficiency Virus HIV, Hepatitis B virus - HBV, Hepatitis C virus HCV, Cytomegalovirus CMV, Malaria, Syphillis)
For patient: Determine blood group
Cross matching: Donor blood cells tested against recipient serum
How is cross-matching conducted?
Recipient serum (containing antibodies - Ig’s) is obtained
Donor blood sample is added to serum in test tube or slide
Recipient Ig’s target donor RBCs
Agglutination/hemolysis = not used
No agglutination/no hemolysis = used
Hemolysis is dangerous because RBC contents (e.g. Hb and K+) are released into the plasma
Which blood groups are compatible with each other?
Donor A –> Recipient A or AB
Donor B –> Recipient B or AB
Donor AB –> Recipient AB
Donor O –> Recipient O, A, B or AB
Why does transfused plasma rarely cause agglutination?
The transfused plasma (donor’s plasma) is usually so diluted in the recipient that it rarely causes agglutination of recipient RBCs.
What are the complications of incompatible blood transfusion?
Severe cases:
* Agglutinated RBCs block capillaries causing pain and tightness of the chest
* Clumps are hemolyzed, releasing Hb which blocks renal tubules causing acute renal failure
* Hemolyzed RBCs release K+ producing hyperkalemia that stops the heart during diastole
* Agglutination reaction releases histamine, producing vasodilation, that leads to severe hypotension and tachycardia that may lead to circulatory shock.
* Patient could die within a week
Mild cases: Pains, tightness of chest, shivering, hypotension, hemoglobinuria, post transfusion jaundice (due to increase bilirubin from the destructed RBCs).
Describe the management during blood transfusion.
- Slow rate of transfusion at the start
- Recipient should be under close supervision within first ½ hour of transfusion
- With any symptoms of incompatibility:
*Immediate stop transfusion
Support circulation + antihistaminic + corticosteroid
What are some of the non-hemolytic complications of blood transfusion?
- Transmission of blood borne diseases (e.g., AIDS, hepatitis B & hepatitis C, malaria, syphilis)
- Citrate intoxication in massive blood transfusion
- Overloading patients with cardiac diseases
- Iron overload
How is an Rh +ve baby affected if the mother is Rh -ve?
First baby, some Rh +ve blood cells pass into the mother’s circulation
Immune system of the mother will form the anti-D agglutinins
If the mother gets pregnant again with Rh +ve baby, the anti-D agglutinins will cross the placenta and hemolyze Rh +ve cells of the baby.
Baby develop erythroblastosis fetalis: If severe reactions baby die in utero. Could also develop Kernicterus, Edema, Jaundice, Anemia
How is a reaction between Rh +ve mother and second Rh -ve baby prevented?
Inject the mother by anti-D antibodies within 72 hours of delivery to prevent her sensitization
