Products and Factors for Bleeding Flashcards
What are the two types of platelet donors
‘Random Donor’ Platelets
Apheresis single donor platelets
Compare Random donor vs apheresis single donor platelets
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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
Why are apheresis donors men
Men tend to not have HLA antibodies
How are apheresis platelets made
Take off 75% of plasma and replace with platelet additive solution
i.e. platelets suspended in 25% male plasma solution
Compare the shape of resting platelets vs activated platelets
Resting platelets are smooth and disc shaped
Activated platelets have an irregular shape with many protruding pseudopodia
What is the platelet swirl test
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
How are platelets processed
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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
Why do we irradiate platelets and not rbc packs
There is no shortening on the life span of platelets when irradiated unlike rbcs
Why do we test for CMV in healthy patients and how do we remove it?
(4)
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
Who might need a platelet transfusion?
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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)
What are two congenital platelet adhesion and aggregation defects
Bernard Soulier and Glanzmanns disease
What is NAITP
Neonatal alloimmune thrombocytopoenia
What response is there when a patient receives a platelet transfusion?
(3)
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
What platelet count indicates need for transfusion
Platelet count less than 50x10^9/L
What is our commercial factor 8 called
Advate
What is our commercial fibrinogen product called
Haemocomplettan
When might fibrinogen be given
In a mass bleed to stop bleeding
What is our albumin commercial product called
Flexbumin
What is haemophilia
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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
What is Haemophilia B also called
Christmas disease
What lab tests would indicate haemophilia
PT normal
APTT prolonged
Describe the life of a severe haemophiliac before treatment was made available
Usually wheelchair bound by childhood due to bleeds in their joints
Haemorrhaging into tissues and joints fixed their joints in place
How did we used to treat Haemophiliacs
Used to give them full plasma
How do we treat Haemophiliacs now
After the discovery of cryoprecipitate we began using factor 8 transfusions
We used to use human-isolated factors (lyophilised)
We now use recombinant products
What is cryopercipitate
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
Why can it be difficult to treat haemophiliacs
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)
How are our factor 8 concentrates processed today
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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
Give an example of a recombinant factor VIII used in Ireland
Advate Recombinant factor VIII
What is von Willebrands Disease
(5)
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
Why is VWD similar to Haemophilia A
VWF circulates with FVIII
VWF supports factor 8 levels
What does VWF do
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
How did we used to treat VWD
Used to give human isolate factor 8 as some human derived factor 8 will have vWF
e.g. Humate P Wilate and Cryoprecipitate
What is desmopresin and what does it do
A drug that causes an increase in factor 8 and VWF
How do we treat VWD today
Use (DDAVP injection) Desmopressin
Or Human sourced factor 8 and vWF
Write about factor 9 concentrates for Haemophilia B and how they are used in treatment
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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
What is ALPROLIX
Purified recombinant factor 9
Why is it less likely to develop factor 9 antibodies than factor 8 antibodies
Factor 9 is a much smaller molecule
What is activated factor 7 and when is it given
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
What is cryoprecipitate
Cold insoluble globulin fraction of plasma rich in factor 8, VWF and fibrinogen
How is cryoprecipitate made
(4)
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
What is a special use of cryoprecipitate
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
What do we use now instead of cryoprecipitate
Isolated human fibrinogen -> Haemocomplettan P
In your own words how is cryoprecipitate made
(5)
Plasma frozen at -18 degrees
Plasma thawed to 1-6 degrees
Plasma centrifuged
Supernatant removed (Cryo-supernatant)
Remainder in pack is cryo-precipitate
