Transfusion

Question 1

What blood components are available (one donor)?

Answer 1

Red cells
Platelets
Fresh frozen plasma
Cryoprecipitate

Question 2

What blood products are available (many donors)?

Answer 2

Human Albumim
Intravenous immunoglobulin
Human normal immunoglobulin concentrates
Specific immunoglobulins (eg tetanus,  hepatitis B, varicella-zoster, rabies, immunoglobulins)			
Anti-D immunoglobulin
Prothrombin complex concentrates

Question 3

What are the ABO groups?

Answer 3

A- A antigen, anti-B antibodies
B- B antigen, anti A antibodies
AB- A and B antigen, no antibodies (universal recipient)
O- No antigens, anti A and anti B antibodies (universal donor)

Question 4

What are most naturally occurring ABO antibodies?

Answer 4

IgM (pentameric structure)

Some IgG

Question 5

Describe the genetics behind ABO blood group

Answer 5

Ch 9- A and B Genes

O Gene is silent, A and B is co-dominant

Question 6

What are the phenotypes of each genotype?

Answer 6

OO-O
AA or AO-A
BB or BO-B
AB-AB

Question 7

What is the other main blood group type?

Answer 7

Rh (D)

+ or - (most +ve)

Question 8

Describe the genetics of Rh(D)

Answer 8

Ch 1
2 alleles: D and d
DD and Dd +, dd -

Question 9

What happens when a Rh(D)- individual is exposed to Rh(D)+ red cells (either pregnancy with + foetus or transfusion)?

Answer 9

One will develop anti-Rh(D) antibody (often shortened to anti-D)
Another exposure may result in reaction

Question 10

What are some indications for red cell transfusion?

Answer 10

Anaemia

Acute blood loss

Question 11

What are some possible indications for platelet transfusion?

Answer 11

Low platelet count - how low?
Patient age
Symptoms of bleeding
Direction of change of platelet count
Platelet kinetics
Underlying infection/ fever
Concomitant anaemia
Concomitant drugs
Requirement for / recovery from surgery
Congenital platelet functional defects
Acquired platelet functional defects eg myeloma, uraemia

Question 12

What happens in an acute haemolytic transfusion reaction?

Answer 12

Activation of complement, coagulation and kinin systems

Question 13

What does the complement cascade causes in transfusion reaction?

Answer 13

Release of C3a and C5a: 
Powerful anaphylotoxins
Increase vascular permeability
Dilate blood vessels
Cause release of serotonin and histamine – fever, chills, hypotension, shock

Formation of MAC leads to rupture of transfused cells

Question 14

What does coagulation cause in transfusion reaction?

Answer 14

Thromboplastic material from haemolysed red cells leads to indiscriminate activation of the coagulation
mechanism – Disseminated Intravascular Coagulation

Question 15

What activates the kinin system in transfusion reaction?

Answer 15

Factor XII

Question 16

What does the kinin system cause in transfusion reaction?

Answer 16

Formation of bradykinin- arteriolar dilatation, increased vascular permeability
Leads to hypotension, which in turns leads to release of catecholamines- leads to vasoconstriction within kidneys and other organs

Question 17

What are the features of immediate haemolytic transfusion reaction?

Answer 17

May begin after only 1 ml is transfused
Pyrexia / rigors
Faintness / dizziness
Tachycardia / tachypnoea /hypotension
Pallor / sweating
Headaches / chest or lumbar pain
Local pain at infusion site
Cyanosis
Patient may say “something is wrong”
All of this may be difficult to recognise if patient is unconscious

Question 18

What is required if an immediate haemolytic transfusion reaction occurs?

Answer 18

Stop transfusion
Start IV fluids to maintain BP and urine output
Obtain samples

Question 19

What are the features of delayed haemolytic transfusion reaction?

Answer 19

Haemolysis usually 5-10 days post transfusion
Symptoms / signs similar to, but less acute than, a IHTR
Unexplained fall in Hb value as transfused red cells are destroyed
Appearance of jaundice, renal failure or biochemical features associated with IHTRs
Detection of positive DAGT or irregular antibodies in post- transfusion blood samples

Question 20

What are the lab features of delayed haemolytic transfusion reactions?

Answer 20

Anaemia, spherocytic red cells on blood film
Elevated bilirubin and LDH
Positive DGAT and/or appearance of red cell allo-antibody
+- a degree of renal failure

Question 21

What are the features of febrile non-haemolytic transfusion reactions?

Answer 21

2% of red cell, and 20% of platelet, transfusions
Rapid temperature rise 1 - 2oC, chills, rigors
Antibodies to contaminating white cells
Release of cytokines and vasoactive substances from white cells during storage
May be difficult to differentiate these symptoms from those of very early acute HTR

Question 22

How is febrile non-haemolytic transfusion reaction investigated?

Answer 22

HLA antibodies may be detectable

No evidence of red cell incompatibility

Question 23

How is febrile non-haemolytic transfusion reaction prevented?

Answer 23

Anti-pyretics

Leucodepleted blood cmoponents

Question 24

Describe urticarial transfusion reactions?

Answer 24

Mast cell - IgE response to infused plasma proteins
Rash / weals within few minutes of starting transfusion
Slow the transfusion
Consider anti-histamines

Question 25

Describe circulatory overload

Answer 25

Pulmonary oedema likely

Higher risk in elderly and those with CCF

Question 26

Describe bacterial infection due to transfusion

Answer 26

Fever, chills, vomiting, tachy, hypotension
Immediate collapse
Shock
DIC

Red cells: pseudomonas, Yersinia
Platelets: staph, strep, serratia, salmonellae

Question 27

Describe the viral infection transfusion reaction

Answer 27

HIV 1 per 6 million units
HBV 1 per 1.6 million
HCV 1 per 26 million