What are the 2 main blood group systems?
- RhD: based on presence or absence of Rhesus D surface antigen. In men it doesn’t matter as much they can have O+ if nothing else available cos won’t lead to HDN obv but matching is better to reduce transfusion reactions
- ABO: presence of A/B antigens on surface, antibodies produced to antigens that are not on your own RBC surface so type AB has no antibodies as they cant make antibodies against their own antigens, and type O has no antigens so has anti-A and anti-B antibodies
What is the significance of Rhesus grouping in pregnancy?
RhD- women will make RhD antibody if they are exposed to RhD+ blood - for the patient if they are given + blood is fine as they can’t attack their own RBCs that are negative for the antigen, however in pregnancy the anti-D antibodies can cause HDN
may be caused by sensitising events, or for the next child if the current one happens to be RhD=
Why is O negative the universal donor?
Although O blood as anti-A and anti-B antibodies in plasma, it has no antigens on the RBC, so even if recipient has antibodies they will not attack the RBC (probably)
What is the universal recipient?
AB positive
There are no antibodies in the plasma so they can’t mount an immune response to donor blood
Packed red cells
- Ind: Hb<70 (may be higher threshold), symptomatic anaemia, acute blood loss, severe sepsis Hb <90
- Given over 2-4h
- Specific risks are iron load if repeated, autoantibodies (so do a new G+S for extra transfusions after 3)
Fresh frozen plasma
Contains clotting factors
- Universal FFP donor is AB as lacks the antibodies in the plasma
- Ind: DIC, all major haemorrhage (usually after 2nd PRC), haemorrhage due to liver disease, prophylactically in some surgeries
- Given over 30 mins
Cryoprecipitate
Made from plasma, contains fibrinogen, vWF, factor VIII, fibronectin, small volume per unit
- Ind: DIC with low fibrinogen, vWD, massive haemorrhage esp in haemophilia
- Given stat
Platelets
*Ind: haemorrhagic shock from trauma, thrombocytopenia <20, or <30 with active bleeding, or <100 if severe bleeding/at a critical site like CNS. Not for ITP, TTP, heparin-induced!
General complications of PRC transfusions?
- Clotting abnormalities from dilution effect - reduce by giving FFP+plts after 4 PRC units
- Hypocalcaemia - citrate in preservative chelates calcium
- Hyperkalaemia - partial haemolysis
- Hypothermia - esp in major haemorrhage rapid transfusion can drop core temp
- Arrhythmias from hypothermia + hyperkalaemia
Acute haemolytic reaction
Usually cos of ABO incompatibility - activation of complement + cytokines - donor cells destroyed by recipient’s antibodies - haemolysis
CF: fever, urticaria, anxiety, haemoglobinuria, hypotension, generalised bleeding from DIC
Ix: low Hb, low haptoglobin, high LDH, high bili, positive DAT
M: stop transfusion, tell blood blank, supportive (O2, fluids, specialist)
Transfusion-associated circulatory overload (TACO)
CF: sudden sob, fluid overload, severe hypoxaemia
Ix: urgent CXR
M: oxygen + diuretics, prophylaxis if at risk (e.g. HF) with furosemide
Transfusion-related acute lung injury (TRALI)
A type of ARDS causing non-cardiogenic pulmonary oedema
CF: sob, hypotension, fever within 6h post-transfusion
high mortality, start high flow O2 + ITU input
Fluid overload
Each unit of PRC is 450ml so need to monitor esp in elderly + CHF
Mild allergic reactions
Pruritis - give an anti histamine like chlorphenamine than can continue transfusion
Non-haemolytic febrile reactions
Usually non-life threatening, antibodies against donor leucocytes (rather than in TRALI which is against recipients) - stop transfusion, give antipyretic + antihistamine
Anaphylaxis
Because recipient is allergic to protein components in the donor blood
Onset min-hour, need regular obs to identify
What are the potential delayed transfusion reactions?
- Infection e.g. vCJD, hep C (shouldn’t know but who knows)
- Delayed haemolytic reaction: antibodies to minor antigens like Kidd, 3-14d later due to secondary response. Causes drop in Hb, fever, jaundice, haemoglobinuria
- Graft vs host disease: HLA-mismatch esp when transfuse non-irradiated blood to immunocompromised pt. CF fever, skin involvement (may be TEN), D+V, mortality 100%
- Iron overload: esp in repeated transfusions, can cause cirrhosis, bronze diabetes, cardiomegaly, conduction disturbance, arthralgia, hyper pigmented skin
Who needs CMV negative blood products?
- Neonates, pregnant women, intra-uterine transfusion
- because CMV can cause sensori-neural deafness + cerebral palsy
*Pt who are likely to need BM/SC transplant in future, or who are on specific clinical trials
Who needs irradiated blood products?
- Hodgkin lymphoma, after SCT, receiving blood from 1st/2nd degree family members, after anti-thymocyte globulin therapy, on certain chemos, intra-uterine transfusion, in first 6m of age, congenital immune deficiency
- Is to reduce risk of graft vs host disease
What bloods are done before giving a transfusion?
Label at pt bedside
G+S - before XM, and if blood loss not anticipated but is a possibility, looks for blood groups + atypical antibodies, takes ~40m, doesn’t issue blood
XM - physically mixes pt plasma + donor red cells to look for immune reaction. If no reaction is released for use - takes ~40m. do if anticipate blood loss
Consenting for transfusions
- Informed written consent where possible, if regular only need at beginning, for surgical do when consent for procedure, for emergencies get written if time allows otherwise document verbal consent, emergency obv can do in unconscious
- Pros: depend on the condition
- Potential risks: extremely small risk of viral illness, very small risk of bacterial infection, risk of transfusion reaction (allergic or haemolytic), unknown but prob extremely small risk of vCJD, v small risk of receiving unsuitable product, alternative options
How many units should you prescribe for non-active bleeding?
.Usually 1 unit RBC, and re-assess after each transfusion
What do you give blood products through?
A green (18G) or grey (16G) cannula (otherwise haemolyse) through a blood giving set which has a filter in the chamber
What is the initial management of a suspected transfusion reaction?
- Stop transfusion, maintain venous access
- O2
- Crystalloid fluids in haemolytic
- Diuretics in TACO
- Adrenaline 0.5ml (500mcg) or 1:1000 IM + hydrocortisone infusion
