Blood Transfusion

Question 1

What is the process by which whole blood is filtered and white blood cells removed?

Answer 1

Leucodepletion

Question 2

What are the main constituents of whole blood?

Answer 2

RBC
Platelets
Plasma:
- Fresh frozen (

Question 3

What is the process by which the main constituents of whole blood separated?

Answer 3

Centrifugation

Question 4

How much in ml is one unit of RBC?

Answer 4

275ml

Question 5

What are the storage conditions for RBC storage?

Answer 5

4 degrees for up to 35 days

Plasma is removed and replaced by solution of electrolytes, glucose and adenine - keeps RBC healthy

Question 6

From removal from cold environment, what is the time limit for blood transfusion? How long does it take

Answer 6

within 4hrs

Between 1.5-3 hrs

Question 7

Why do we transfuse patients?

Answer 7

To prevent symptoms of anaemia
Improve quality of life
Prevent ischaemic damage

NOT normalise Hb (Hb conc will remain the same, just number of RBCs will be lower)

Question 8

What are the symptoms of anaemia the result of?

Answer 8

Tissue hypoxia

Question 9

At what point should a blood transition be given (transfusion threshold)?

Answer 9

The lowest concentration of Hb where symptoms of anaemia are not observed

Question 10

Name the mechanisms by which the body adapts to anaemia (i.e. maintain tissue oxygenation)?

Answer 10

• Increased cardiac output
• Increased 2,3 DPG
• Increased cardiac artery flow
• Increased EPO production
• Increase erthroproiesis
• Increased O2 extraction

Question 11

what factors are used to determine the transfusion threshold of patients?

Answer 11

Acute vs chronic - less time for adaptation mechs to develop so termite anaemia less well

Underlying conditions - resp, CV, age - tolerate anaemia less well

Question 12

Why are RBCs transfused?

Answer 12

To restore oxygen carrying capacity

Question 13

What are the transfusion thresholds for patients and patients with CV disease who have mild symptoms of anaemia?

Question 14

When are RBC transfusions to given?

Answer 14

Individuals with preventable causes of anaemia e.g. iron, B12, folate deficiency, renal disease (erythropoietin therapy is choice treatment)

Individual requiring correction of coagulopathy

Question 15

Which blood loss, what is the amount of blood loss required to necessitate a transfusion?

Answer 15

> 2000 ml

Question 16

What is the transfusion threshold level for individuals with chronic anaemia?

Answer 16

Hb 80-100 g/L

• set individual threshold and set Hb concentration targets

Question 17

What considerations should we have for individuals receiving blood transfusions?

Answer 17

Iron overload - avoid over transfusion

Causes cardiomyopathy and liver failure

Question 18

What is the transfusion threshold for individuals receiving regular transfusions due to inheritable conditions? What is the objective of this?

Answer 18

Hb 90-95 g/L

• avoid iron overload
• Suppression of endogenous erythropoiesis

Question 19

What are the optimum storage conditions for plasma?

Answer 19

22 degrees, 5 day shelf life

Question 20

How long does it take to transfuse plasma?

Answer 20

30 mins/unit

Question 21

Why are platelets transfused?

Answer 21

Thrombocytopenia/platelet dysfunction

-Prevention of bleeding

Question 22

What are the contraindications for platelet transfusion?

Answer 22

Heparin induced thrombocytopenia and thrombosis

Thrombotic thrombocytopenia purpura

Question 23

What are he storage conditions/shelf life for fresh frozen plasma?

Answer 23

• 30 degrees
• 24 months
• Thawed for 20-30 mins immediately before use
• takes 30 mins to transfuse

Question 24

How many units does an average adult require?

Answer 24

4-6 units (12-15mg/kg/unit)

Question 25

What are the main indications for use of fresh frozen plasma?

Answer 25

Coagulopathy with bleeding/surgery Massive haemorrhage Thrombotic thrombocytopenia purpura

Question 26

What patients is Fresh frozen plasma not used?

Answer 26

Individuals with warfarin overdose Individual with single factor deficiency

Question 27

What are the some special requirements for transfusions?

Answer 27

CMV negative - protect at risk patients from CMV e.g. pregnant women,

Question 28

Pre trans lab testing. What comprises the group and screen process?

Answer 28

Test donors ABO/Rh(D) group -Test patient plasma for antibodies against clinically significant blood group antigen

Question 29

What comprises the pre transfusion lab testing of 'crossmatching?'

Answer 29

Correct donor ABO/Rh groups are selected for patient Donor blood is mix ed with patient plasma to see if there is any reaction e.g. haemolysis/agglutination Reaction = incompatible; risk of haemolysis

Question 30

What are the risks of transfusion? how are they classified?

Answer 30

Acute/chronic | Immunological/non-immunological

Question 31

Name so acute immunological conditions associated with blood transfusion

Answer 31

ABO incompatibility (acute haemolytic transfusion reaction) Allergic/anaphalaxic reaction

Question 32

Name some acute non-immunological conditions associated with blood transfusion

Answer 32

bacterial contamination

Question 33

Name some chronic immunological reactions due to transfusion

Answer 33

Transfusion associated graft vs host disease | Post transfusion purpura

Question 34

Name some chronic non-immunological reactions due to blood transfusion

Answer 34

Transfusion transmitted infection | Virus e.g. HIV/prion disease

Question 35

What is the main cause of symptoms in acute haemolytic reaction with ABO incompatibility?

Answer 35

Free Hb in blood

Question 36

What are the symptoms of Acute haemolytic reaction - APO incompatibility

Answer 36

``` Fever and chills Back pain Infusion pain Hypotension/SHOCK HAEMOGLOBURIA (Hb in urine) Increased bleeding (DIC) ```

Question 37

What type of error is acute haemolytic reaction (APO compatibility)? When does it most likely occur?

Answer 37

ALWAYS human error Most likely with blood administration

Question 38

What are the clinical features of delayed haemolytic syndrome?

Answer 38

Fatigue Jaundice Fever

Question 39

What are the lab findings associated with delayed haemolytic syndrome?

Answer 39

- Reduced Hb - Increase Lactate dehydrogenase - Increase inactive bilirubin (hence jaundice)

Question 40

What is delayed haemolytic syndrome caused by?

Answer 40

IgG antibodies that react to antigens other than those of ABO. Occurs 3-14 day post transfusion

Question 41

What is the Coombs test used for? How does it work?

Answer 41

Used to test for presence of antibodies on RBCs (delayed haemolytic syndrome) Antihuman globulin added to blood - agglutination = positive for antibodies

Question 42

What is transfusional related acute lung injury? How is it treated?

Answer 42

Antibodies against recipients leukocytes/granulocytes are present in donor blood. Causes damage to lung endothelium and capillaries. Supportive treatment O2/ventilation