Haem: Blood Transfusions Pt.2

Question 1

What should you do if a patient receiving a platelet transfusion develops a fever?

Answer 1

• Stop the platelets and take blood cultures
• Platelets should be sent back to the lab for microbiological testing

Question 2

If a patient develops a reaction to a plasma transfusion, what is the most likely cause?

Answer 2

Allergic reactions

NOTE: plasma is frozen so it is unlikely to get contaminated by bacteria

Question 3

List some indications for RBC transfusion.

Answer 3

• Major blood loss - if >30% blood lost
• Peri-operative care - if Hb <70g/dL
• Post-chemotherapy - if Hb <80g/dL
• Symptomatic anaemia - ischaemic heart disease, breathless

Question 4

By how much would 1 unit of RBC increase the haemoglobin leel in a 70kg patient?

Answer 4

10 g/L

Question 5

If a group and screen is performed and no antibodies are present, is a crossmatch necessary?

Answer 5

No

Question 6

List some methods of transfusing your own blood.

Answer 6

• Pre-operative autologous deposit (not available in the UK)
• Intra-operative cell salvage (blood is collected during surgery, centrifuged, filtered and reinfused)
• Post-operative cell salvage (blood that is lost post-operative is collected via a wound drain, filtered and re-infusd - usually for orthopaedic operations)

NOTE: all coagulation factors and platelets are removed in cell salvage

Question 7

Which patient groups would cell salvage be used for?

Answer 7

• Patients with rare blood groups
• Jehovah’s witnesses

Question 8

Which patient groups require CMV-negative blood?

Answer 8

• For intra-uterine and neonatal transfusions
• Elective transfusion in pregnancy

Question 9

Which patients require irradiated blood and why?

Answer 9

Highly immunosuppressed patients

• These patients cannot destroy donor lymphocytes and the presence of lymphocytes in donated blood can cause transfusion associated graft-versus-host disease

Question 10

Which patients require washed blood?

Answer 10

• Patients who have severe allergic reactions to donors’ plasma proteins
• This takes 4 hours so must be requested in advance

NOTE: IgA deficient patients are more likely to need washed blood

Question 11

List some indications for platelet transfusions.

Answer 11

• Massive transfusion - aim for >75 x 10^9/L
• Prevent bleeding (post-chemotherapy) - if <10 x 10^9/L
• Prevent bleeding (surgery) - if <5 x 10^9/L
• Platelet dysfunction or immune cause - only if actively bleeding

Question 12

List some contraindications for platelet transfusion.

Answer 12

• Heparin-induced thrombocytopaenia
• TTP

Question 13

By what level will 1 unit of platelets increase the platelet count in a 70 kg adult?

Answer 13

30-40 x 10^9/L

Question 14

List some indications for FFP transfusion.

Answer 14

• Massive transfusion
• DIC (if bleeding or invasive procedure)
• Liver disease

Question 15

What does FFP contain?

Answer 15

All the coagulation factors

Question 16

What is the adult dose of FFP?

Answer 16

15 mL/kg

4 units

Question 17

How many mLs is 1 unit of FFP?

Answer 17

250mL

Patients usually given 4 units

Question 18

What is the best option for the reversal of warfarin?

Answer 18

Prothrombin complex concentrate (contains 2, 7, 9 and 10)

Question 19

What does cryoprecipitate contain?

Answer 19

• Fibrinogen
• FVIII and vWF
• Fibronectin
• FXIII
• Platelet microparticles
• IgA
• Albumin

Question 20

What is the most common blood type?

Answer 20

O positive (1/3 of donors)