Blood Transfusion Flashcards Preview

Clinical Pathology > Blood Transfusion > Flashcards

Flashcards in Blood Transfusion Deck (42):
1

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

Leucodepletion

2

What are the main constituents of whole blood?

RBC
Platelets
Plasma:
- Fresh frozen (

3

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

Centrifugation

4

How much in ml is one unit of RBC?

275ml

5

What are the storage conditions for RBC storage?

4 degrees for up to 35 days
Plasma is removed and replaced by solution of electrolytes, glucose and adenine - keeps RBC healthy

6

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

within 4hrs

Between 1.5-3 hrs

7

Why do we transfuse patients?

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)

8

What are the symptoms of anaemia the result of?

Tissue hypoxia

9

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

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

10

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

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

11

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

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

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

12

Why are RBCs transfused?

To restore oxygen carrying capacity

13

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

14

When are RBC transfusions to given?

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

Individual requiring correction of coagulopathy

15

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

>2000 ml

16

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

Hb 80-100 g/L

- set individual threshold and set Hb concentration targets

17

What considerations should we have for individuals receiving blood transfusions?

Iron overload - avoid over transfusion

Causes cardiomyopathy and liver failure

18

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

Hb 90-95 g/L

- avoid iron overload

- Suppression of endogenous erythropoiesis

19

What are the optimum storage conditions for plasma?

22 degrees, 5 day shelf life

20

How long does it take to transfuse plasma?

30 mins/unit

21

Why are platelets transfused?

Thrombocytopenia/platelet dysfunction
-Prevention of bleeding

22

What are the contraindications for platelet transfusion?

Heparin induced thrombocytopenia and thrombosis

Thrombotic thrombocytopenia purpura

23

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

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

24

How many units does an average adult require?

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

25

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

Coagulopathy with bleeding/surgery

Massive haemorrhage

Thrombotic thrombocytopenia purpura

26

What patients is Fresh frozen plasma not used?

Individuals with warfarin overdose

Individual with single factor deficiency

27

What are the some special requirements for transfusions?

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

28

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

Test donors ABO/Rh(D) group

-Test patient plasma for antibodies against clinically significant blood group antigen

29

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

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

30

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

Acute/chronic
Immunological/non-immunological

31

Name so acute immunological conditions associated with blood transfusion

ABO incompatibility (acute haemolytic transfusion reaction)

Allergic/anaphalaxic reaction

32

Name some acute non-immunological conditions associated with blood transfusion

bacterial contamination

33

Name some chronic immunological reactions due to transfusion

Transfusion associated graft vs host disease
Post transfusion purpura

34

Name some chronic non-immunological reactions due to blood transfusion

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

35

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

Free Hb in blood

36

What are the symptoms of Acute haemolytic reaction - APO incompatibility

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

37

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

ALWAYS human error

Most likely with blood administration

38

What are the clinical features of delayed haemolytic syndrome?

Fatigue
Jaundice
Fever

39

What are the lab findings associated with delayed haemolytic syndrome?

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

40

What is delayed haemolytic syndrome caused by?

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

41

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

Used to test for presence of antibodies on RBCs (delayed haemolytic syndrome)

Antihuman globulin added to blood - agglutination = positive for antibodies

42

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

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

Supportive treatment O2/ventilation

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