Blood Transfusion

Question 1

Blood groups

Answer 1

Arise form antigens. Red cell antigens are expressed on the cell surface (proteins, sugars, lipids). These are determined genetically.

Question 2

Type O

Answer 2

Absence of antigens

Question 3

ABO blood group antigens

Answer 3

ABO gene encodes glycosyltransferase. Glycans added to proteins or lipids on Red Cells
A and B genes code for transferase enzymes
A antigen is N-acetyl-galactosamine
B antigen is galactose
‘O’ gene is non-functional allele
So A and B are (co-)dominant and O is recessive

Question 4

Blood group antibodies

Answer 4

These can be due to immune tolerance or IgM (anti-A/B naturally occurring antibodies which are developed via gut bacteria in the first few weeks of life)

Question 5

A

Answer 5

42%

Question 6

B

Answer 6

9%

Question 7

AB

Answer 7

3%

Question 8

O

Answer 8

46%

Question 9

Universal donor

Answer 9

Blood type O can be received by any patient

Question 10

Universal recipient

Answer 10

Blood type AB

Question 11

Universal donor of FFP

Answer 11

AB

Question 12

Blood group O FFP

Answer 12

unsafe from all donors

Question 13

RhD blood group system

Answer 13

RhD and RhCE (homologous to RhD) Next immunogenic system. A transmembrane protein which is very immunogenic. Acts as classic antigen. Will not make antibody unless you’ve seen it before. Large proportion of the population are Rhdd (RhD negative)

Question 14

Anti-RhD

Answer 14

RhD negative individuals can make anti-D if exposed to RhD+ cells
Transfusion or pregnancy
Anti-D can cause transfusion reactions or haemolytic disease of the newborn

Question 15

Blood donors

Answer 15

Extensive ‘behavioural’ screening
Sex, age, location…………
Tested for ABO and Rh blood groups
Screened for HepB, HepC, HIV, syphilis (sometimes screened for other infections depending on travel)

Question 16

Plasma

Answer 16

Fresh frozen plasma (frozen, if require clotting factors this can be put in immediately)

Cyroprecipitate (rich in factor 8, mixed with alcohol, rich in fibrinogen)

Factor concentrates, immunoglobulin and albumin

Question 17

Red Cells

Answer 17

Stored at 4oC
Shelf life 35 days
Transfuse over 2-4 hrs

Question 18

Indications for tranfusion of red cells

Answer 18

Surgery, obstetric, trauma
Medical: GI haemorrhage, bone marrow failure, chemotherapy, severe anaemia refractory to other therapy
Other: HDN, sickle cell anaemia, thalassaemia etc etc

Question 19

Platelets

Answer 19

Cool platelets from four donors together and stored for 5 days. Transfuse over 20-60 minutes.

Question 20

Indications for platelets

Answer 20

Massive haemorrhage
(Keep platelet count above 75x109/l)

Bone marrow failure
(platelet count <10-15 × 109/litre
or <20 × 109/litre if additional risk, e.g. sepsis)

Prophylaxis for surgery
(Minor procedures 50x109/l;
More major surgery 80x109/l; CNS or eye surgery 100x109/l)

Cardiopulmonary bypass
(Platelets should be readily available, use only if bleeding)

Question 21

Fresh frozen plasma

Answer 21

1 unit from 1 unit of blood

Stored frozen, allow 30 minutes to thaw

Question 22

Indications for FFP

Answer 22

massive haemorrhage (use in 1:1 ratio?), coagulation factor replacement.
DIC with bleeding
Liver disease - in the presence of bleeding or prior to invasive procedures
Use prothrombin complex concentrate for warfarin reversal

Question 23

Lab test for FFP

Answer 23

PT and APTT

Question 24

Cryoprecipitate

Answer 24

2 pools if fib <1.0g/dl (1.5g/dl)

Stored frozen; allow 30 minutes to thaw

Question 25

Lab test for cyroprecipitate

Answer 25

Fibrinogen

Question 26

"Practical Blood Banking"

Answer 26

Blood sent to lab ‘Second sample’ now implemented Group and Save Cross match -Tariff defined by ’MSBOS Samples kept for 7 days -but only valid for 2 days if recent transfusion

Question 27

Blood Grouping and Antibody Screening

Answer 27

ABO and RhD type Checked against historical records Screen for allo-antibodies in serum

Question 28

Coombs Test

Answer 28

Direct anti-globulin test, whether there is antibody attached to the surface of cells. Anti-human immunoglobulin is added.

Question 29

Direct Coombs Test

Answer 29

autoimmune haemolytic anaemia passive anti-D haemolytic transfusion reactions

Question 30

Indirect Coombs Test

Answer 30

Cross matching. Serum from the plasma and then the Coombs Reagents

Question 31

Red Cell Availability

Answer 31

Minutes – O RhD Neg red cells, AB plasma and group A plasma Urgent – Type specific (ABO/ RhD) Non-urgent – Full cross match, select correct ABO/RhD type. If allo-antibodies choose antigen negative blood.

Question 32

Massive Haemorrhage Policy

Answer 32

Immediate supply of: 6 units red cells 4 units FFP (cryoprecipitate?) 1 unit platelets

Question 33

Risk of Transfusion

Answer 33

Death or harm (transfusion or ABO incompatible components) Tranfuscion associated cardiac overload (left ventricular failure) Transfusion associated lung injury Acute transfusion reaction Febrile ractions Allergic reactions

Question 34

Minor reactions to blood

Answer 34

Fever usually below 38 degrees, urticarial rash Treat with paracetamol and antihistamine 1% of transfusions

Question 35

Major reactions to blood

Answer 35

Fever, urticaria, respiratory distress, hypotension, tachycardia, oliguria, bleeding and collapse

Question 36

Management of reactions

Answer 36

Stop transfusion Check patient identity Consider: anaphylaxis, circulatory overload (TACO), acute haemolytic transfusion reaction (AHTR), bacterial infection, lung injury (TRALI) (other…)

Question 37

Treatment of TACO

Answer 37

Slow rate, IV diuretic (20mg of furosemide) , and oxygen

Question 38

ABO Haemolytic Reactions (acute)

Answer 38

immediate, complement mediated lysis or IgM or IgG complement fixing Shock, high fever, renal failure Treat with O2, IV fluids, diuretics, inotropes, dialysis

Question 39

Delayed Haemolytic Reactions

Answer 39

Due to IgG antibodies. Anaemia and jaundice 7-10 days post-transfusion. Do positive direct anti-globulin test (COOMBS test)

Question 40

Bacterial Infection

Answer 40

Platelets. Treat with IV antibiotics, O2 and IV fluids.

Question 41

TRALI

Answer 41

Oxygen, respiratory support and IV fluids. Notify the blood service to investigate/initiate recalls.

Question 42

Prion Disease

Answer 42

Transmittable by blood transfusion from early in disease in sheep. New variant Creutzfeldt-Jakob disease.

Question 43

Development of Maternal AntiD antibodies

Answer 43

Haemolytic anaemia resulting from IgG crossing the placenta in subsequent pregnancies. Presents with anaemia and jaundice. Give Anti-D just before birth. All mothers screen, if they are negative they are tested for antibodies against it. Check dopplers, increased blood flow treated with RhD- cells

Question 44

Neonatal Alloimmune Thrombocytopenia similar process for platelets

Answer 44

bleeding and thrombocytopenia in the first few days after birht

Question 45

Leucapheresis

Answer 45

Bone marrow harvest, donor lymphocyte infusions.

Question 46

Process of of blood grouping

Answer 46

Red cell group is determined by suspending washed red cels with diluted anti-A, anti-B, anti-AB and anti-Rh(D). Agglutination indicates a positive test.

Question 47

Compatibility testing

Answer 47

This entails suspension of red cells from a donor pack with recipient serum, incubation to allow reactions to occur and examination for agglutination, including an indirect antiglobulin test to ensure that no reaction has occured.

Question 48

Indications for use of cyroprecipitate

Answer 48

DIC, liver disease, von Willebrand disease