Blood Transfusions

Question 1

What are the different types of blood?

Answer 1

ABO and RhD positive or negative. Aruond 85% of people have RhD positive blood.

Question 2

What testing is done to keep blood transfusions safe?

Answer 2

Units are tested before each transfusion,- no matter how many times it has been done before

• Patient observations measured 15 minutes into transfusion, and hourly after that to check for reactions
• Samples are barcoded and moved by machines to reduce error
• Blood must be written at the bedside, by the person taking out the blood, by hand

Question 3

How are red blood cells stored? When are they indicated? How are they given?

Answer 3

They are stored at 4 degrees Celsius, and can only be put back in the fridge if left out for less than half an hour. They have a shelf life of 35 days, and must be used within 4 hours of removal. 1 unit is given over 2-3 hours.

They are indicated in haemorrhage and usually given when Hb falls below 80 or 70.

Question 4

How are platelets stored? When are they indicated? How are they given?

Answer 4

They are stored at 22 degrees Celsius and can be kept for 7 days. 1 unit is given over 20-30 minutes.

They are indicated in haemorrhage and pre-procedurally. Do not give in consumptive disorders such as TTP, ITP and DIC.

Post-chemo: given if platelets <10
Pre operations: <50
Pre CNS or eye operations: <100

Question 5

How is fresh frozen plasma? When are they indicated? How are they given?

Answer 5

It is frozen and takes 30-40 minutes to thaw. 1 unit is given over 20-30 minutes. It must be MB treated for children and given at a rate of 15ml per kg.

It is indicated in major haemorrhage, DIC and liver disease.

Question 6

Name some adverse reactions to transfusions, and give a method to classify them. Describe these reactions too.

Answer 6

Acute: occurring within 24 hours
Immune:
- ABO incompatibility (chest or loin pain, shock, take investigations)
- Febrile non-haemolytic (common, give paracetamol)
- Allergic (plasma reaction, urticaria, give antihistamines)
- Transfusion related acute lung injury (TRALI) (within 6 hours, pulmonary infiltrates, white cell reaction, no raised JVP)

Non-immune:

• Bacterial infection (platelets most likely, fever, shock)
• Transfusion associated circulatory overload (TACO) (pulmonary oedema, raised JVP, give furosemide)

Late: occurring after 24 hours
Immune:
- Delayed haemolytic transfusion reaction (within a week, raised bilirubin)
- Post-transfusion purpura (purpura on body, within 7-10 days, in those who are HPA-1a negative, treat with IVIG)
- Transfusion associated graft versus host disease (Ta-GVHD) (rare, 99% are fatal, supportive treatment)

Non-immune:

• Viral infections (rare, malaria, Hep B, HIV etc.)
• Iron overload (treat with iron chelation exjade)

Question 7

What is haemolytic disease of the new-born

Answer 7

Where maternal antibodies attack foetal antigens causing severe anaemia and jaundice. Usually after a previous sensitisation of the mother with anti-D.

Question 8

How is haemolytic disease of the new born avoided?

Answer 8

Anti-D is given to rhesus negative mothers to avoid sensitisation from a rhesus positive baby.

It is given at:

• 28 weeks and 34 weeks
• Delivery
• Sensitising events (ECV, amniocentesis, CVS, miscarriage, haemorrhage)
• 250 units before 20 weeks, 500 units after 20 weeks (with Kleihauer test after 20 weeks)