Lecture 8: Practical aspects of transfusions Flashcards
What are the aims of pretransfusion testing?
- To provide RBC for transfusion that will survive normally in the recipients circulation
- To avoid heamolytic transfusion reactions
What are the sources of transfusion errors?
- Wrong pt wrong sample
- Lab procedures
- Blood issuing and collection
- Wrong blood wrong patient
FOLLOW THE FORMS
Describe the bedside procedure for transfusion testing
- 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
What are the three steps of pre-transfusion testing?
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
What three areas do the blood ordering policies center around?
1) Group and screen
2) Compatibility testing
3) Emergency situation
Describe the group and screen policy
- Used in surgical setting when likelihood of bleeding is low
- Ab screens should be negative
- Means red cells can be provided quickly
Describe the compatibility testing policy:
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
Describe the policy around the provision of red cells in emergency setting:
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
Whats the final bedside check when giving blood?
- Should involve two independant persons
- Check patient identity against compatibility label: Full name, DOB, NHI, Blood group
Describe the monitoring of tranfusions:
Monitor pt closely following transfusion
- Major problems likely to produce early signs/symtpoms
- If problems develop:
- > Stop transfusion
- > Maintain line with saline
- > Seek advice
What are some possible complications of tranfusions?
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
How do you differentiate acute transfusion reactions?
- Bacterial sepsis
- Anaphylaxis
- Heamolytic
- circulatory overload
- febrile non heamolytic transfusion reactions
Difficult to differentiate the possible causes on clinical grounds alone
How does bacterial sepsis from transfusion present?
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
What are the main complications of heamolytic reactions?
- renal failure
- DIC
10% fatal
What are the symptoms and signs of heamoyltic reactions?
Symptoms:
- Fever
- Restlessness
- Retrosternal or loin pain
Signs
- Increased temperature
- Hypotension
- Uncontrolled bleeding
Write some notes on extravascular heamolytic reactions:
IgG antibody in patient plasma
- Rh antibodies
- Keel, duffy, kidd etc
Compliment activation
- DOES NOT OCCUR
Clinically indistinguishable from acute intravascular heamolysis
Write notes on delayed heamolytic tranfusion reaction:
- 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
Write some notes on febrile non-heamolytic transfusion reactions:
- 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
How do you manage FNHTR?
- Stop transfusion
- Maintain line with normal saline
- Investigate; Samples to blood bank, check for sepsis
- Medicate: Paracetamol and possibly antihistamine
Write some notes on transfusion related acute lung injury (TRALI):
- 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
Write some notes on circulatory overload:
- 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
Write some notes on allergic reactions to transfusions:
- 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
