Lecture 8: Practical aspects of transfusions

Question 1

What are the aims of pretransfusion testing?

Answer 1

• To provide RBC for transfusion that will survive normally in the recipients circulation
• To avoid heamolytic transfusion reactions

Question 2

What are the sources of transfusion errors?

Answer 2

• Wrong pt wrong sample
• Lab procedures
• Blood issuing and collection
• Wrong blood wrong patient

FOLLOW THE FORMS

Question 3

Describe the bedside procedure for transfusion testing

Answer 3

• Correctly identify patient (Name, DOB)
• Label sample beside bed
• Declaration on request form by person drawing blood that the info is all correct and the labelled sample matches the patients details

Question 4

What are the three steps of pre-transfusion testing?

Answer 4

1) Determine ABO and Rh(D) type of recipient (Against Hx record or if new then do twice)
2) Antibody screen
3) Select blood component

Question 5

What three areas do the blood ordering policies center around?

Answer 5

1) Group and screen
2) Compatibility testing
3) Emergency situation

Question 6

Describe the group and screen policy

Answer 6

• Used in surgical setting when likelihood of bleeding is low
• Ab screens should be negative
• Means red cells can be provided quickly

Question 7

Describe the compatibility testing policy:

Answer 7

3 broad approaches:

• Full cross match (takes 45 mins), used if antibody screen is positive
• Immediate spin cross match (5-10 mins), aims to detect ABO incompatibility
• Computer cross match (<5 mins), final ABO check performed electronically

Question 8

Describe the policy around the provision of red cells in emergency setting:

Answer 8

3 main approaches usually used sequentially

• Emergency O Rhd neg (desperate situation, blood type unknown)
• Group specific blood (desp, blood type known)
• Provision of fully compatible blood

Question 9

Whats the final bedside check when giving blood?

Answer 9

• Should involve two independant persons

- Check patient identity against compatibility label: Full name, DOB, NHI, Blood group

Question 10

Describe the monitoring of tranfusions:

Answer 10

Monitor pt closely following transfusion

• Major problems likely to produce early signs/symtpoms
• If problems develop:
• > Stop transfusion
• > Maintain line with saline
• > Seek advice

Question 11

What are some possible complications of tranfusions?

Answer 11

Immunological:
Early: Heamolytic reactions, allergic reactions, febrile non-heamlytic reaction, transfusion related acute lung injury
Late: Delayed heamolytic reactions. post transfusion purpura, graft vs host disease

Non-immunological
- Bacterial or viral transmission

Question 12

How do you differentiate acute transfusion reactions?

Answer 12

• Bacterial sepsis
• Anaphylaxis
• Heamolytic
• circulatory overload
• febrile non heamolytic transfusion reactions

Difficult to differentiate the possible causes on clinical grounds alone

Question 13

How does bacterial sepsis from transfusion present?

Answer 13

Classically presents as sudden onset of hypotensive shock occurring within minutes of starting a transfusion

Very rare

More likely in platelets as stored at 12 not 4 degrees

Question 14

What are the main complications of heamolytic reactions?

Answer 14

• renal failure
• DIC

10% fatal

Question 15

What are the symptoms and signs of heamoyltic reactions?

Answer 15

Symptoms:

• Fever
• Restlessness
• Retrosternal or loin pain

Signs

• Increased temperature
• Hypotension
• Uncontrolled bleeding

Question 16

Write some notes on extravascular heamolytic reactions:

Answer 16

IgG antibody in patient plasma

• Rh antibodies
• Keel, duffy, kidd etc

Compliment activation
- DOES NOT OCCUR

Clinically indistinguishable from acute intravascular heamolysis

Question 17

Write notes on delayed heamolytic tranfusion reaction:

Answer 17

• Classically occurs 7-10 days post transfusion
• Pt Hb falls associated with slight jaundice
• Caused by anamnestic antibody response;
• > Sensitization by previous transfusion or pregnancy
• > Ab not detectable during pre transfusion testing

Question 18

Write some notes on febrile non-heamolytic transfusion reactions:

Answer 18

• Relatively common
• Occur most frequently association with platelet transfusion but also with red cell components
• Fever >38 degrees usually starting during transfusion
• Often associated with rigors
• Clinically often indistinguishable from hemolytic reactions
• Results of cytokines and other biological response modifiers that accumulate in blood products during storage

Question 19

How do you manage FNHTR?

Answer 19

• Stop transfusion
• Maintain line with normal saline
• Investigate; Samples to blood bank, check for sepsis
• Medicate: Paracetamol and possibly antihistamine

Question 20

Write some notes on transfusion related acute lung injury (TRALI):

Answer 20

• Donor plasma contains white cell antibodies leading to agglutination and sequestration of neutrophils in pulmonary vasculature.
  i. e Donor antibody recognizes HLA/neutrophil specific antigen in recipient

Big cause of morbidity and mortality in transfusions

Question 21

Write some notes on circulatory overload:

Answer 21

• Underlying circulatory function is determinant of this
• At risk: Compromised CV function, those in volume overload states such as renal failure or congestive cardiac failure. Or large volumes compared to intravascular volumes i.e child or elderly

= Give diuretic to make space first

Question 22

Write some notes on allergic reactions to transfusions:

Answer 22

• Usually involve reactions to plasma proteins

Two types:
Anaphylaxis (Rare, early onset, low BP, dyspnea, Abdo cramps) - typically IgA deficient who has anti IgA

Urticarial (Minor, common) Slow transfusion and administer antihistamine