L8. Transfusion Flashcards
What are the 6 steps in ensuring safe transfusion
- Correct patient identification
- (state name, dob), blood sampling and handwritten labelling at bedside - Determination of ABO and Rh(D) type of recipient
- Antibody screen designed to detect clinically significant antibodies -eg. anti (D)
- Selection of appropriate RBC for transfusion: usually group for group
- Final cross match or compatibility test
then Removal of selected RBC units from the blood refrigerator and - Final identity check at bedside
What type of test is the antibody screen, ABO and Rh (D) determination
Antibody screen:
- Anti-human globulin technique to specially selected cells that will enable identification of clinically significant antibodies
ABO/Rh (D)
- done through automatic cell typing cassette. twice for patient with no known history, once to compare to historical record
What is a group and screen compared to a full cross match test (compatibility test) and immediate spin cross match
What is the right situation for it and how long they take
(before issuing the final ABO check is performed electronically)
- Group and screen is the general test of ABO, RhD and antibody screen of serum retained in lab for 7 days. Takes 40 min
- Used alone pre surgery when likelihood of blood required is low - if the antibody screen is negative.
Red cells can be provided quickly when needed (within 15 min)
- Full Cross match involves Anti-HG testing of patient serum, primarily if antibody screen is positive. This takes up to 45min and has to be done after the g&s so need to be done if blood loss is anticipated
ABO incompatibility can be tested 5-10 minutes with immediate spin crossmatch
What are the 3 approaches to providing RBCs in an emergency situation in time order
the emergency blood isn’t given all the time due to limited resources
- Emergency O Rh (D) negative units: if patient group is unknown - It assumes patient doesn’t have any antibodies to other antigens.
- Group specific blood: ABO and D matched
- Provision of fully matched blood
When are symptoms of acute transfusion reaction (1-2% of patients) likely to occur and what should you do then
Early symptoms of major problems within the first 15 minutes then intermittently afterward.
If problems
- Stop transfusion
- Maintain the line with saline
- Seek advice - maybe need adrenaline etc
What are the differential diagnoses of an acute transfusion reaction: early, immunological vs non immunological (5,2)
Immunological
- immediate Haemolytic reaction
- Anaphylaxis
- Febrile non haemolytic reaction (annoyance; leucofiltration related)
- Transfusion related acute lung injury
- Circulatory fluid overload (give diuretics)
Non immunological
- Bacterial sepsis
- Viral transmission
What is the presentation of bacterial sepsis: bacteria making endotoxin in the blood , how common is it with RBC v Platelets and how can it occur
Presents as sudden onset hypotensive shock occurring minutes of starting transfusion - unrecognised will be death/morbidity
Less common in RBC at 4’C compared to Platelets at room temp.
It can occur if there was bacteria in the blood of donor from colorectal fistula or contamination from skin of recipient etc
What are the signs and symptoms (6) related to the processes in intravascular haemolytic reaction
and are they distinguishable from extravascular haemolysis ?
Symptoms/signs
Cytokine storm activated by complement leads to
- Fever: increased temperature
- Restlessness; feeling of death
- Retrosternal or loin pain
-Hypotension
-Uncontrolled bleeding (from release of thromboplastic substances causing DIC)
-Dark brown urine - from heme liberation from haemolysis
EV haemolytic reactions are clinically indistinguishable from IV. - although in reality they don’t activate complement, only to early phase.
What is a delayed haemolytic reaction mechanism, when does it occur and presentation
Other is post transfusion purpura, graft vs host disease
Mechanism is due to amamnestic antibody response where they are sensitised to something due to previous transfusion/pregnancy but antibody is not detectable during pre transfusion testing so when transfused they get resensitisation and increased antibody count.
eg. Kid antibody.
Happens 7-10days post transfusion. Presenting Patient Hb falling with slight jaundice
When are you allowed to give Rh (D) positive blood to someone who is Rh (D) negative in an emergency and what do you have to do later
Male and female over 56 yrold due to end of reproductive capacity
have to be careful about next transfusion being Rh (d) negative because they are likely to develop anti D antibodies
What is a Febrile Non haemolytic transfusion reaction mechanism, when does it occur and presentation
Acute reaction in response to cytokines + other biological response modifiers that accumulate in blood components during storage, due to the WBC antigens coming off.
More common in platelet than RBC transfusion but overall frequency has reduced with pre storage leucodepletion
Presentation is fever >38’C during transfusion, associated with rigors and often indistinguishable from other haemolytic reaction
What is the management of Febrile Non haemolytic transfusion reaction. what is not recommended?
- stop transfusion
- maintain line with normal saline
- Investigate
- samples to blood bank for transfusion reaction investigation
- blood culture to exclude sepsis - Medication:
- Paracetamol and possible antihistamine if reaction occurs
Hydrocortisone is not recommended
What is Transfusion related acute lung injury mechanism, when does it occur, presentation
How is it prevented
Major mortality/morbidity
Mech: transfusion of donor plasma containing WBC antibodies (anti-HLA) lead to agglutination and sequestration of recipient neutrophils in the pulmonary arteries.
This leads to protein exudate in lungs like oedema on xray- but don’t give diuretics
Prevented
- Fresh frozen plasma can only be donated by Male that have never been transfused
- Platelet apheresis donors are screened for anti HLA antibodies
What patient risk factors put greater risk of transfusion associated circulatory overload
- Compromised CVS function
- Volume overload state already: renal or congestive heart failure
- Elderly and children which have naturally lower intravascular volume
Compare the two type of allergic reactions to plasma proteins
- how common, presentation
then what is the common case for 1. and the treatment for 2.
- Anaphylaxis
- rare but severe early onset reaction.
- presents with hypotension, dyspnoea, abdo cramps.
- occurs in IgA deficient individual who has anti IgA antibodies - Urticarial
- common but mild
- presents with hives and itching
Treatment is slow transfusion and administration of anti-histamine
