Practical aspects of transfusion

Question 1

the aim of pre transfusion testing

Answer 1

provide red cells for transfusion that will survive normally in recipients circulation
to avoid haemolytic transfusion reactions

Question 2

Steps in ensuring safe transfusion

Answer 2

correct identification, sampling and labelling
Determination of the ABO and Rh(D) type of the recipient
antibody screen designed to detect clinically significant antibodies
Selection of appropriate red cells for transfusion
A final cross match or compatibility test
Removal of selected red cell units from blood refrigerator
final identity check at bedside

Question 3

common sources of transfusion error

Answer 3

wrong patient sample
lab procedures
blood issuing and collection
wrong blood wrong patient

Question 4

The pre-transfusion sample procedures

Answer 4

Patient ID - confirmed by asking the patient (if conscious and coherent) to state their given names and DOB, and by checking their identity label
Sample labelling - done at bedside, preprinted labels not accepted
Confirmed on request form - check information on the sample label and wristband are correct before leaving the patient

Question 5

The 3 steps of pre-transfusion testing

Answer 5

Determine ABO and Rh(D) type of recipient
- known patient compared to historical record
- Unknown patient checked twice
Antibody screen
- Specifically selected cells that will enable identification of clinically significant antibodies
- Anti human globulin technique
Selection of blood component

Question 6

Blood ordering policies

Answer 6

Group and screen
Compatibility testing
Emergency situations

Question 7

Group and screen

Answer 7

in surgical settings when likelihood of blood being required is low
Antibody screen should be negative
serum retained in lab for 7 days
Red cells can be provided quickly when needed (within 5 mins)

Question 8

Compatibility testing

Answer 8

3 board approaches

1. Full crossmatch
   - AGH testing
   - Progressive decline in use
   - Used primarily when antibody screen is positive
2. Immediate spin cross match (5-10mins)
   - Aims to detect ABO compatibility
3. Computer crossmatching (5 mins)
   - Final ABO check performed electronically

Question 9

Emergency situations

Answer 9

Effective communication essential 
3 main approaches, sequential 
Emergency O, Rh(D) negative units 
- Requirement for blood desperate, patient group not known 
- Group specific blood 
Provision of fully compatible blood

Question 10

Final bedside check

Answer 10

Common form of error 
should involve two people 
check patient identity against compatibility label 
- Full name 
- DOB 
- NHI 
- Blood group

Question 11

Monitoring transfusion / what to do when things go wrong?

Answer 11

Monitor patient closely 
Major problems likely to produce early warning signs 
If symptoms develop 
- stop transfusion
- Maintain line with saline 
- Seek advice

Question 12

immunological complications of transfusions

Answer 12

early 
- haemolytic reactions 
- febrile non haemolytic reactions 
- TRALI 
- Reactions to proteins 
Late 
- Delayed haemolytic reactions 
- Post transfusion purpura 
- Graft versus host disease

Question 13

Non-immunological complications of transfusion

Answer 13

Bacterial and viral transmission

Question 14

What is an immediate haemolytic reaction?

Answer 14

Red cell rupture from antibody attack = leaking of Hb into plasma

Question 15

What happens when small fragments of compliment liberated vs hemolysis

Answer 15

symptoms and signs including hypotension –> acute renal failure –> symptoms associated with circulatory failure
Whereas hemolysis ends up like disseminated intravascular coagulation

Question 16

Immediate haemolytic reaction

• symptoms
• signs

Answer 16

symptoms 
- fever 
- restlessness 
- retrosternal or lion pain 
Signs 
- increased temperature 
- Hypotension 
- Uncontrolled bleeding

Question 17

Delayed haemolytic transfusion reaction

Answer 17

Classically occurs 7-10 days post transfusion
Patient Hb fall associated with slight jaundice
Anamnestic / memory response
- sensitisation by previous transfusion or pregnancy
- antibody not detectable during pre transition testing, but in memory B cells in lymph nodes
potentially avoidable

Question 18

Immediate Intravascular haemolytic reactions

Answer 18

ABO incompatibility 
Main complications 
- renal failure 
- DIC 
30% long term morbidity, 10% mortality 
usually preventable

Question 19

Extravascular haemolytic reactions

Answer 19

IgG antibody in patient plasma
- Rh antibodies, Kell, Kidd, Diffy etc
Complement activation
- Does not occur
Clinically indistinguishable from acute intravascular haemolysis
Sometimes you will even get hemoglobinurea from leakage of products of red cell destruction by the spleen and liver

Question 20

Febrile non- haemolytic transfusion reactions

Answer 20

relatively common
Fever > 38 degrees usually starting during transfusion
Often associated with rigors
clinically often indistinguishable from haemolytic reactions

Question 21

Pathophysiology of FNHTR

Answer 21

classically caused by white cells in red cell component

presence of antibodies to white cells e.g. HLA antibodies in the recipient

Question 22

Management of FNHTR

Answer 22

Stop transfusion 
Maintain line 
Investigate 
Take blood cultures 
Medication 
- paracetamol
- Antihistamine 
- Hydrocortisone

Question 23

Transfusion related acute lung injury (TRALI)

Answer 23

onset of acute lung injury within 6 hours of transfusion
transfusion of donor plasma containing white cells leads to agglutination and sequestration of recipient neutrophils in the pulmonary vasculature
- Requires donor antibody to recognise HLA/ neutrophil ‘specific agent’ in recipient
Major mortality and morbidity associated with transfusion
blood services developing strategies to reduce risk
- use of male only FFP
- screening platelet pheresis donors for HLA antibodies

Question 24

Post transfusion purpura

Answer 24

Body produces alloantibodies to the introduced platelets antigens.
Alloantibodies destroy patients platelets –> thrombocytopenia usually 7-10 days post transfusion
potentially fatal
Rare, usually in women who have had multiple pregnancies or in people who have had a previous transfusion
Usually in individuals who lack HPA-1a antigen patients develop antibodies to HP-1a antigen –> platelet destruction (or HPA-5b)
Possible explanation: recipients platelets acquire phenotype of donors platelets, by binding of soluble antigens
Treatment: IVIG therapy or plasmapheresis

Question 25

Reactions to plasma proteins

Answer 25

1. Anaphylaxis
   - rare
   - early onset, severe reaction
   - hypotension, dysphoria, abdominal cramps
   - Classically occurs in IgA deficient individual who has anti IgA antibodies, –> give washed red cells and plasma
2. Urticarial
   - common
   - Slow transfusion and admin anti histamine