Blood Transfusion Flashcards
Name the A and B antigens
A and B antigens are made by action of transferase enzymes on H, adding either
A = N acetyl galactosamine
B = galactose
For the following blood groups what are the antibodies in the plasma and the antigens in the RBC?
Group A, B, AB and O
Group A = anti-B antibodies, A antigen
Group B = anti-A antibodies, B antigen
Group AB = none, A and B antigens
Group O = anti-B and anti-A antibodies, none
What is the prevelance of each of the blood groups
O = 45% A = 43% B = 9% AB = 3%
What are the ‘other’ blood groups
Rh 'rhesus' Kell Duffy Kidd M N S s Antibodies usually only form in response to transfusion or pregnancy
Red cells
- storage instructions
- shelf life
- transfusion time
- other features
Stored at 4 degrees C
Shelf life 35 days
Trasnfusion over 2-3 hours
Plasma reduced, optimal additive solutions
Platelets
- what is a dose?
- storage instructions
- shelf life
- transfuse over…..
- Dose = 1 unit (4 WB donations or 1 apheresis)
- Stored at room temp (aggitator), shelf life 7 days
- Transfuse over 30 to 60 minutes
Plasma
What is the dose?
Storage instructions
12-15ml/kg, 3 to 4 units per dose
stored frozen, allow 30 minutes to thaw
Who is universal donor for the following?
- red cells
- plasma (not cellular)
- platelets
- O RhD negative
- AB (A)
- AB RhD negative (A)
Who is the universal recipient of the following?
- red cells
- plasma (not cellular)
- platelets
- AB RhD pos
- O
- O RhD neg
What questions do you need to ask when deciding Does the patient need blood?
- Why are they anaemic/thrombocytopaenic/coagulopathic?
- What else can be done to correct it?
- How long will that take?
- Can they wait?
- Are they bleeding?
- Are you giving prophylaxis or treatment?
What is the dose of RBCs?
- approx 10g/L per unit for an average 70kg adult
What are the triggers for transfusion of RBCs?
- acute blood loss with haemodynamic instability
- Hb <70g/L stable patient
- Hb <80g/L if cardiovascular disease
- chronic transfusion dependent anaemia
A platelet dose of 1 unit should increase platelet count by….
30
What are the triggers for transfusion of platelets
- prophylactic platelet trasnfusion
- prior to invasive procedure or therapy
- therapeutic to treat significant bleeding
- specific clinical conditions
- platelet dysfunction
What is the dose of FFP?
- Dose = 15ml/kg of body weight, often equivilant to 4 units in adults
What are the trigger for transfusion of FFP?
- major haemorrhage
- INR >1.5 with bleeding
- INR >1.0 and pre-procedure
- Liver disease with INR >2 and pre-procedure
What is a dose of cryoprecipitate?
- Dose - 2 pooled units, equivialnt to 10 individual units, will increase fibrinogen by approximately 1g/L
What are the triggers for transfusion of cryoprecipitate?
- clinically significant bleefing and fibrinogen <1.5g/l
- fibrinogen <1g/l and preprocedure
Define major haemorrhage
- loss of more than one blood volume within 24 hours (around 70ml/kg, >5litres in a 70kg adult)
- 50% of blood volume lost in less than 3 hours
- blleeding in excess of 150ml/minute
What is appropiate dose of blood products in the major haemorhage protocol?
4 units RBCs
4 units FFB
What are the immune complications/adverse effects of transfusion?
- ABO incompatible
- FNHTR - febrile non-haemolytic TR
- DHTR - delayed haemolytic TR
- allergic
What are the infectious complications/adverse effects of transfusion?
Viral
Bacterial, syphliic
parasites
prions
What are the ‘other’ complications/adverse effects of transfusion?
iron overload
fluid overload TACO
What are the consequences of bacterial contamination?
HOw does it occur?
Bacterial sepsis - especially if endotoxin produced e.g. gram neg rods (E.coli)
Hypotension, tachcardia and fever within minutes of starting transfusion
ABcerita acquired from donor skin,
Risk reduced by - stringent cleaning, diver pouch, bacerial screening
CAN BE FATAL
What is an acute haemolytic reaction due to?
Can be fatal because…
ABO mismatch
Can be fatal soon after transfusion
- immediate complement mediated cell lysis due to IGm and anti A and anti B
- hypotension, tachycardia, fever, renal failure, DIC, death
- As little as 10mls can be fatal
HOw should an acute haemolytic reaction be managed?
- STOP transfusion
- IV fluids to maintain BP
- FBC, coag screen, chemistry
- repreatd blood group
- return blood to blood bank
- blood cultures
- intensive care, treat DIC, dialysis
Describe a DHTR
Delayed Haemolytic Transfusion Reaction
- due to previously stimulated RBC antibodies (Rh, Kell, etc
- 7 to 10 days post transfusion
- Fall in Hv and jaundice
- DAT positive (direct antiglobulin test)
Describe FNHTR
Febrile Non-Haemolytic Tranfusion Reaction
- during or soon after transfusion
- fever and tachucardia
- unpleasant but not life threating - must exclude wrong blood or bacterial infection
- less since leucodepletion of blood and platelets
Describe allergic reactions
- urticarial rash +/- wheeze –> often not sevre, hypersensitivity to random protein
Anaphylaxis - severe, life-threatening reaction soon after transfusion started
- wheeze/asthma, tachycardia, hypotension
- laryngeal/facial oedema
Which patients are at risk of a TACO
Transfusion Associated Cardiac Overload
- elderly
- pre-existing heart disease
- low weight patients
- renal/liver impairment
- concomitant IV fluids
- diuretic use
What is TRALI
Transfusion related Acute lung injury
- tranfused antibodies in donor plasma interact with patients white cells
What are the 3 questions in the TACO checklist?
- Does the patient have heart disease?
- Do they have pulmonary oedeme
- Is fluid balance clinically significantly positive?
