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2.2 Transfusion Science > Products and Factors for Bleeding > Flashcards

Products and Factors for Bleeding Flashcards

1
Q

What are the two types of platelet donors

A

‘Random Donor’ Platelets
Apheresis single donor platelets

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2
Q

Compare Random donor vs apheresis single donor platelets
(3)

A

Random -> single donor units containing at least 45-85 x10^9 per donation. Usually pooled in 4-6 unit bags and issued to the hospitals. Units would have approx 250-300 mls plasma

Apheresis -> contain at least 240 x 10^9 platelets per unit. Suspended in 300mls approximately of male donor plasma.

Both ABO grouped if possible

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3
Q

Why are apheresis donors men

A

Men tend to not have HLA antibodies

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4
Q

How are apheresis platelets made

A

Take off 75% of plasma and replace with platelet additive solution

i.e. platelets suspended in 25% male plasma solution

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5
Q

Compare the shape of resting platelets vs activated platelets

A

Resting platelets are smooth and disc shaped

Activated platelets have an irregular shape with many protruding pseudopodia

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6
Q

What is the platelet swirl test

A

If platelets have activated e.g. if bacteria present in plasma then they won’t swirl, you will be able to see clumps in pack

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7
Q

How are platelets processed
(4)

A

Agitated during storage to prevent unacceptable platelet aggregation

All platelet products in Ireland are ‘leucodepleted’ by filtration

All platelet products are irradiated since 2006

CMV antibody tested (donor) for appropriate immunosuppressed patients e.g. neonates, BMT, chemotherapy

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8
Q

Why do we irradiate platelets and not rbc packs

A

There is no shortening on the life span of platelets when irradiated unlike rbcs

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9
Q

Why do we test for CMV in healthy patients and how do we remove it?
(4)

A

CMV is always there in your system

CMV hides itself in wbcs

When you irradiate the platelets you remove the wbcs and thus the CMV (pack deemed CMV negative but not deffinite)

We can test for CMV antibodies but this is only done in special cases e.g. for neonates

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10
Q

Who might need a platelet transfusion?
(6)

A

Bone marrow failure e.g. aplastic anaemia, leukaemia

Chemotherapy

Acute DIC -> platelets consumed in clots

Dilutional thrombocytopoenia -> massive transfusion

Congenital platelet adhesion and aggregation defects

Neonatal alloimmune thrombocytopoenia (NAITP)

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11
Q

What are two congenital platelet adhesion and aggregation defects

A

Bernard Soulier and Glanzmanns disease

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12
Q

What is NAITP

A

Neonatal alloimmune thrombocytopoenia

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13
Q

What response is there when a patient receives a platelet transfusion?
(3)

A

One unit of random donor platelets should raise the count by 5-10 x10^9/L

Anticipate platelet refractoriness (stubborness) - non response - may be due to excessive consumption or antibody mediated destruction

May indicate selection of HLA or HPA matched donor platelets

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14
Q

What platelet count indicates need for transfusion

A

Platelet count less than 50x10^9/L

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15
Q

What is our commercial factor 8 called

A

Advate

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16
Q

What is our commercial fibrinogen product called

A

Haemocomplettan

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17
Q

When might fibrinogen be given

A

In a mass bleed to stop bleeding

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18
Q

What is our albumin commercial product called

A

Flexbumin

19
Q

What is haemophilia
(3)

A

Inherited bleeding disorders, usually classified as mild, moderate and severe

Either FVIII (Haemophilia A) or FIX (Haemophilia B) deficient

Both X-linked disorders with female carriers and male sufferers

20
Q

What is Haemophilia B also called

A

Christmas disease

21
Q

What lab tests would indicate haemophilia

A

PT normal
APTT prolonged

22
Q

Describe the life of a severe haemophiliac before treatment was made available

A

Usually wheelchair bound by childhood due to bleeds in their joints

Haemorrhaging into tissues and joints fixed their joints in place

23
Q

How did we used to treat Haemophiliacs

A

Used to give them full plasma

24
Q

How do we treat Haemophiliacs now

A

After the discovery of cryoprecipitate we began using factor 8 transfusions

We used to use human-isolated factors (lyophilised)

We now use recombinant products

25
Q

What is cryopercipitate

A

Discovered accidently when a plasma pack was left in a fridge overnight and it froze

The pack contained flakes/precipitates which contains factor 8, VWB and fibrinogen

We were able to isolate these to treat haemophiliacs

26
Q

Why can it be difficult to treat haemophiliacs

A

Can be difficult to separate VWB factor from Factor 8

Can have a very strong antibody response to factor 8 (these antibodies are produced when a person doesn’t naturally have this factor, these are called inhibitors)

27
Q

How are our factor 8 concentrates processed today
(4)

A

Lyophilised - suitable for ‘home’ treatment

Heat treated at 60 degrees for 72 hours

Solvent-detergent treated to disrupt viral coats of Hep B, C and HIV

F VIII gene has been cloned and successfully grown in cell culture media in chinese hamster ovary cells -< recombinant FVIII

28
Q

Give an example of a recombinant factor VIII used in Ireland

A

Advate Recombinant factor VIII

29
Q

What is von Willebrands Disease
(5)

A

Autosomal inherited lack of VWF

Results in mucocutaneous bleeding

Platelet function is impaired

Prolonged Bleeding time -> often seen when someone gets a tooth removed

3 types from mild to severe

30
Q

Why is VWD similar to Haemophilia A

A

VWF circulates with FVIII

VWF supports factor 8 levels

31
Q

What does VWF do

A

VWF binds to collagen and to glycoprotein 1b found on platelets

Binds to collagen, platelets and factor 8

Its the glue that forms a clot

32
Q

How did we used to treat VWD

A

Used to give human isolate factor 8 as some human derived factor 8 will have vWF

e.g. Humate P Wilate and Cryoprecipitate

33
Q

What is desmopresin and what does it do

A

A drug that causes an increase in factor 8 and VWF

34
Q

How do we treat VWD today

A

Use (DDAVP injection) Desmopressin

Or Human sourced factor 8 and vWF

35
Q

Write about factor 9 concentrates for Haemophilia B and how they are used in treatment
(8)

A

Often contain factors 2, 7, 9 and 10

Prothromplex

Octaplex

used for reversal of warfarin overdose

Pure factor 9 is available

Risk of inhibitors lower for F9 than for F8

Recombinant product available called ALPROLIX or BenefIX

36
Q

What is ALPROLIX

A

Purified recombinant factor 9

37
Q

Why is it less likely to develop factor 9 antibodies than factor 8 antibodies

A

Factor 9 is a much smaller molecule

38
Q

What is activated factor 7 and when is it given

A

Given in severe bleeding in haemophiliacs A or B

Factor 7 deficiency is very rare

Has Factor 8 inhibitor bypass activity i.e. given to Haemophiliacs A with inhibitors

e.g. Novoseven

39
Q

What is cryoprecipitate

A

Cold insoluble globulin fraction of plasma rich in factor 8, VWF and fibrinogen

40
Q

How is cryoprecipitate made
(4)

A

Fresh frozen plasma is allowed thaw at 4 degrees

Excess plasma is siphoned off, leaving ppt and some plasma

It is then frozen and stored for use - reconstituted and transfused

Has a half life of 12 hours

41
Q

What is a special use of cryoprecipitate

A

Product can be mixed with thrombin and applied topically to site of bleeding -> Fibrin Sealant/Glue

New type of fibrin sealant

Used in surgery where there is diffuse bleeding e.g. liver surgery

42
Q

What do we use now instead of cryoprecipitate

A

Isolated human fibrinogen -> Haemocomplettan P

43
Q

In your own words how is cryoprecipitate made
(5)

A

Plasma frozen at -18 degrees

Plasma thawed to 1-6 degrees

Plasma centrifuged

Supernatant removed (Cryo-supernatant)

Remainder in pack is cryo-precipitate

2.2 Transfusion Science (22 decks)

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