Transfusion Medicine

Question 1

What are the four main blood components?

Answer 1

Red blood cells
Platelets
Plasma
Cryoprecipitate

Question 2

What’s in the bag of red cells that can be administered at room temperature to patients?

Answer 2

Optimal additive solution containing sugars and chemicals that are friendly for the red cells and enable them to last between 28-35 days before they expire as long as refrigerated
Red cells

Question 3

When should red cells be administered?

Answer 3

To top up people who don’t have enough red cells, including anaemic or major bleeding

Question 4

What does ‘restrictive thresholds’ mean in clinical settings with regard to red cells administration?

Answer 4

If a patient can tolerate a lower haemoglobin/haematocrit, we won’t transfuse them provided there isn’t another reason to transfuse them before that threshold

Question 5

Which trial proved that a restrictive transfusion strategy for ill patients in ICU was not inferior to a liberal transfusion strategy?

Answer 5

TRICC Trial 1999

Question 6

What’s in the bag of platelets?

Answer 6

Platelet additive solution
Platelet pool

Question 7

When are platelets transfused?

Answer 7

When platelets are low in the patient
Especially when the platelets are low and they are bleeding

Question 8

According to the recent British Society of Haematology Guidelines (2016), what is the platelet threshold for non-severe bleeding procedures?

Answer 8

30 x 10 ^ 9 /L

Question 9

According to the recent British Society of Haematology Guidelines (2016), what is the platelet threshold for severe/life-threatening bleeding procedures?

Answer 9

50 x 10 ^ 9 /L

Question 10

What’s in the bag of fresh frozen plasma (FFP)?

Answer 10

Plasma

Question 11

When is FFP used/administered?

Answer 11

To correct factor deficiencies in patients who might need a procedure or who are bleeding/haemorrhage
Given alongside red cells to replace blood that’s lost due to massive haemorrhage/major bleeding

Question 12

How long does it take for FFP to be thawed?

Answer 12

15 minutes to half an hour

Question 13

What is the average volume of a unit of FFP?

Answer 13

250 ml

Question 14

What is the therapeutic dose of FFP for an adult?

Answer 14

4 units

Question 15

What is the volume of fluid of the therapeutic dose of 4 units of FFP for an adult?

Answer 15

1 litre (needs consideration in patients who don’t tolerate volume very well)

Question 16

What is a cryoprecipitate?

Answer 16

Concentrated fibrinogen product with clotting factors

Question 17

When is cryoprecipitate used?

Answer 17

When patients have low fibrinogen
Protocolised for major haemorrhage

Question 18

What are the special considerations for using cryoprecipitate?

Answer 18

Has to be thawed
Should be thought of early in major haemorrhage

Question 19

What is the term used to describe the legal obligation we have to understand where the blood used for transfusion came from (donor) and where it went?

Answer 19

Vein-to-vein traceability

Question 20

What percentage of vein-to-vein traceability should we aim for during transfusion?

Answer 20

100% (most hospitals achieve 90-99%; unusual to get 100%)

Question 21

What needs to be checked or followed to ensure that the right blood is going to the right patient during the transfusion process?

Answer 21

Positive patient identification
Bedside labelling of samples
Electronic patient ID (expensive so not all hospitals have it)
Two sample rule
Electronic issue/lab IT rules
Final bedside check (minimum 4 points - first name, last name, DOB, MRN)
Consent

Question 22

What is one of the biggest/likeliest risks to patients undergoing transfusion?

Answer 22

Human error (ABO-incompatible transfusions)

Question 23

Apart from human error, what are some other risks of transfusion?

Answer 23

Immunological: febrile, allergy, alloimmunisation, transfusion-related acute lung injury (TRALI)
Circulatory: transfusion-associated circulatory overload (TACO)
Infection: bacterial, viral eg HEV, variant Creutzfeldt-Jakob disease (vCJD), the unknown

Question 24

What types of disease in patients should we be concerned about and consider transfusion medicine for in dentistry?

Answer 24

Patients with bleeding disorders or haematological oncology (especially if they have cytopenia or received bisphosphonates)

Question 25

What are some issues in transfusion with regards to thrombocytopenia in dentistry?

Answer 25

Platelet count needed for extraction is unclear

Question 26

In the prospective cohort study in 2012 in liver pre-transplant patients with thrombocytopenia, it was found that there was no significant difference in time to haemostasis. What were the range of platelet count and INR for those patients?

Answer 26

Plts >30
INR <3

Question 27

What conclusion was made from the retrospective cohort study in haematological patients (thrombocytopenic) in 2013 with regards to transfusing patients with platelet count of <50 and their bleeding outcome?

Answer 27

Transfusion had no impact on bleeding outcome

Question 28

According to the retrospective analysis in 2017, what were the predisposing criteria of severe bleeding post-surgery, especially when combined together?

Answer 28

INR >2.5
Platelet count <40