HAEM: Blood transfusion Flashcards by Zuzanna Łoboda

Which blood group antibodies decline with age? What are these associated with in terms of blood transfusion?

Anti-Duffy and Kidd = these can cause delayed transfusion reactions

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In GROUP testing, what type of reaction indicates that the antibody/antigen is present in the patient’s blood?

Present = agglutination at the top 
Absent = RBCs suspended at the bottom of vial

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In SCREEN testing, what technique is used? What are the 3 components?

IAT = indirect antiglobulin technique at 37oC

Using patient serum + lab RBCs + anti-human globulin (AHG)

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What type of antibodies does group vs screen testing test for ?

Group = IgM - prevent immediate reaction
Screen = IgG - prevent delayed reaction

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What is the result of a positive screen test?

Clumping

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How is crossmatching done? What component of donor blood is used?

Plasma is used

Full crossmatch - ises IAT
Immediate spin - emergency only, detects ABO incompatibility only

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Why does AGH have to be added in the screen test?

Because IgG would not cause clumping of the cells by itself like IgM does, so you wouldn’t see the positive result

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Is Kell negative blood used?

Yes - for women of childbearing age

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How is plasma stored?

Frozen - infused over 20-30min

Low risk of bacterial contamination as stored frozen SO if reaction occurs it’s more likely anaphylactic

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Which compatibility needs to be checked for platelets and plasma transfusions?

Platelets = D only 
Plasma = ABO only

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Why are PLATLETS given over 20-30min?

Stored at room temp so high risk of bacterial contamination

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How long can FFP vs cryoprecipitate be stored once thawed?

FFP = keep 24hrs at 4oC
Cryo = keep 4hrs at RT

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When is transfusion indicated in…

(a) major blood bloss
(b) peri-op/critical care
(c) post-chemo

a) if >30% lost
b) if Hb <70g/L and 80g/L respectively
c) if Hb <80g/L

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Name 2 CI to platelet transfusion.

HiTT (heparin induced thrombocytopenia thrombosis)

TTP

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How much does 1U platelets raise plt?

30-40x10^9/L

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When should you consider FFP?

Massive transfusion 
Liver disease
Single factor def
DIC bleeding 
TTP

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What contains 2/7/9/10?

Prothrombin complex concentrate

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Are FFP and plt cross-matched?

No, only group matched

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What does blood irradiation do? What about washing?

Irradiation - prevents TA-GvHD

Washing - removes most plasma, platelets and WBC (useful for IgA deficient patients)

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What is the RBC:FFP given in major bleeding?

1:1 usually x4 each
NB: add 50mg/kg fibrinogen if given more than 4 units

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Name 2 respiratory related acute transfusion reactions.

TACO - circulatory overload

TRALI - acute lung injury

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Other than TACO/TRALI, what are the acute transfusion reactions?

Acute haemolytic (ABO)
Allergic
Infective - bacterial
Febrile non-haemolytic

What is a delayed transfusion reaction?

Occurs >24hrs post-transfusion

Give 4 examples of delayed transfusion reactions.

Delayed haemolytic (Duffy, Kidd) --> alloimmunisation 
TA-GvHD (>2w)
Infective - viral/prion/malaria 
Post transfusion purpura 
Iron overload

What does SHOT and MSBOS stand for?

``` SHOT = serious hazard of transfusion MSBOS = maximum surgical blood ordering schedule ```

What are the first signs of acute reaction to transfusion?

Temp/HR rise BP drop Other symptoms: - flushing, urticaria, pain at site, itching - headache - collapse - vomiting - chest pain

How often do you monitor for transfusion reactions in an unconscious patient?

``` 0min 15min 1hr 2hrs +1hr etc +end of transfusion ```

What is the cause of febrile NHTR? How is it managed?

Cytokine release from WBC during storage | Tx: stop/slow transfusion + paracetamol

What type of haemolysis occurs in ABO incompatibility?

Acute intravascular

What may be seen in urine in ABO incompatibility?

Haemoglobinuria (later sign)

How severe are bacterial transfusion reactions?

severe/fatal - presents like ABO incompatibility with restlessness/vomiting/flushing/collapse

What blood products are most and least associated with contamination?

plt>>RBC>FFP

How long can platelets be stored?

7 days at RT

How long can RBCs be stored?

35 days at 4oC

What is the mechanism of allergic transfusion reaction? Are these reactions severe?

IgE mediated | Usually not severe except IgA DEFICIENCY (common, IgA Abs form when exposed to donor)

What is the cause of TACO and what are some signs/symptoms?

Caused by fluid overload or hypoalbuminaemia. Sx: Fluid overload on CXR, SOB, low sats, high HR and high BP.

What is the cause of TRALI?

No clinical fluid overload but lung injury like ARDS due to ANTI-WBC antibodies in donor blood. These aggregate and stick to capillaries which causes inflammation and lung injury. Sx: SOB, low sats, high BP and high HR, fever, bilateral pulmonary infiltrated within 6hrs of transfusion on CXR

What is the response to diuretics in TACO vs TRALI?

TACO - responds | TRALI - no

What compatibility of platelets and RBC can a patient with... receive? a) O blood b) AB blood

O blood can receive.. - only O RBCs - A, AB, B, O platelets AB blood can receive... - only AB platelets - A, AB, B, O blood

What platelets and RBCs can a patient with B blood receive?

Platelets: B, AB RBC: B, O

What donors should be used for plasma platelets and why?

Male for both - not likely to be sensitised so no HLA/HNA Abs

What is the most common delayed TR and what is the consequence of this?

Delayed haemolytic = against Kell, Duffy | --> ALLOIMMUNISATION

What is the management of alloimmunisation?

Repeat group and screen

Who receives CMV negative blood?

Preg and neonates

What is the pathophysiology of TA-GvHD? How do you prevent it?

Immunosuppressed patients cannot destroy donor lymphocytes which are able to divide and destroy tissue Prevention: irradiate blood or HLA-match

What are the signs/symptoms of TA-GvHD?

gut --> diarrhoea liver --> failure skin --> desquamation and BM failure

When does post-transfusion purpura occur?

7-10 days later

Who is affected by post-transfusion purpura?

Human platelet antigen 1-ve patients Previously immunised patients via blood or transfusion Exact mechanism UNKNOWN

What is the management of post-transfusion purpura?

IVIG - will resolve in 1-4 weeks

How much iron in each unit of blood?

200-250mg

When is a Kleinhauer test done?

Bleeding over 20 weeks and at delivery only

What volume of fetal-maternal bleed do these anti-D doses cover for? 1) 500IU 2) 1250IU 3) 1500IU

1) 4ml 2) 10ml 3) 12ml

Other than anti-D, name 2 Abs which can cause haemolysis in a newborn.

Anti-C | Anti-Kell