L7. Blood and Blood products Flashcards
Why is it important for blood donors to be voluntary and non remunerated
Paid donation is associated with increased risk of blood borne virus transmission due to poor exclusion of donors with high risk factors
and exploitation of the poor and disadvantaged
Is NZ self sufficient for blood donations? What does this mean, why is this important and how is it done
NZ blood service is a crown entity so financially self sufficient.
Self sufficiency means a country takes active steps to meet requirements for blood and blood products from its own resource.
This is important because
1.Due to increasing populations from donor countries and NZ, buying exported plasma is unsustainable as they will want to keep the excess for themselves.
- There is difficulty in transporting some blood products due to shelf life and temperature of storage
NZ is self sufficient in
- blood components
- most main types of plasma derivatives (processed in CSL Behring AU), but imports rarely needed plasma components.
What are the steps taken to ensure that blood donation results in a product with minimal risk
- Using voluntary non remunerated donors
- Exclusion of potential donors whose behaviour or lifestyle places them at increased risk of acquiring recognised blood borne infections
Or that have risk of complications from donation - Testing of all blood donations for evidence of major blood borne viruses
- Use of physical and chemical methods to destroy any pathogens present - 2 dedicated viral inactivation steps in blood product manufacture
What is the process for selecting donors and what ages are okay to donate, and how often do they donate?
Donate between 16-70 yrold every 12 weeks (to get iron back)
Selection process
- National donor questionaire/health questionaire
- interview with registered nurse to clarify questionaire
- haemoglobin check to check for anaemia
What diseases + general test is donated blood tested for (6 categories)
- ABO, RhD type and antibody screen
- Hep B surface antigen + HBV DNA nucleic acid test
- Hep C antibody and nucleic acid test for HCV RNA
- HIV 1 & 2 antibody and HIV-1 RNA test
- HumanTLymphotropicV Anitbody (first time donors)
- Serological test for syphilis
Why is it still important to exclude donors when you can test for diseases in blood (3)
- To test for all possible transmissible infections is impractical and time consuming - freshness of products important
- There is a window from the time of infection to the time that an infection can be detected due to time for virus to duplicate.
- Detection also dependent on testing method: genome testing being the most sensitive.
Therefore although the risk is small, there is enough donations in NZ that the risk of patient being transfused with infection is substantial
What is special about informed consent for transfusion important in NZ
Specific informed consent must be obtained prior to transfusion - so consent for a procedure is not consent for transfusion.
Define blood component.
Define blood product - What treatment is done to all blood components in manufacturing process
Define plasma derivative in terms of their manufacturing method and give example
- blood product: any product derived from human blood
- blood component: blood product manufactured in a local blood centre derived from a single donation or small pool of 4-6 donations for purpose of direct transfusion
All bc are leucodepleted -removal of WBC by filtration
- plasma derivative is a blood product manufactured from a large pool of plasma donations (1000s) using industrial systems
eg. factor 8 and 9 for haemophilia, immunoglobulin, human albumin solution
What are the 3 types of blood components, the storage temp, shelf life.
Who are the only donors for platelet concentrate and frozen plasma and why
- RBC: 2-6 (fridge) for 35 days.
- Platelet concentrate: 20-24 (room temp) for 7 days
- donated by Group O and A. (for everybody so don’t need AB platelets) - Fresh frozen plasma: -25’ for 2 years
- male apheresis donors because less risk of anti Rh (D) antibodies being transferred
What are the 4 main factors to consider for RBC transfusion for improving O2 delivery to tissues
- Risk of Anaemia:
Hb levels
- <70 for acute anaemia (not rlly chronic)
-70-100 for surgery associated blood loss,
80< to control anaemia symptoms for patient on chronic transfusion/ marrow suppressive therapy - Ongoing Blood loss:
- volume of loss vs normal volume. - Hypoxia made worse by
- Increased O2 consumption (fever, shivering, anaesthesia)
- Atherosclerotic disease
- Patient’s cardiopulmonary reserve - Risk of transfusion
What are the 4 main factors to consider for platelet transfusion for management or prevention of bleeding in patients with low platelet counts
When can it be given earlier/at higher platelet count
(specific one for neonatal use)
- Prophylaxis for
- Bone marrow failure: can give earlier if fever / other risk factors present
- Surgery: give earlier if high risk (neuro, ocular)
- Inherited or acquired (drugs) Platelet function disorder: platelet count isn’t helpful bc they aren’t working.
- Patient bleeding
- When count below trigger level + significant bleeding - Massive haemorrhage: low platelet counts +/- functional abnormalities with significant bleeding from this cause.
- In presence of diffuse microvascular bleeding may be needed early as well.
What are the main factors to consider for Fresh frozen plasma transfusion (1) and what are the 5 indications for its use
- The plasma group donor is chosen to match the recipient’s blood type to avoid passive antibody from plasma haemolysing recipient RBC. AB is ok for A and B. O can be given anything, but No O FFP because it has antibodies to both
Indications
1. Immediate reversal of warfarin effect in the presence of life threatening bleeding
- Replacement of single factor deficiencies/inherited deficiencies of coagulation inhibitor in patients undergoing high risk procedure (where specific factor concentrate not available)
- Treatment of multiple coagulation deficiencies associated with acute DIC
- Bleeding patients with abnormal coagulation parameters following cardiac bypass, massive transfusion, liver disease.
- Thrombotic thrombocytopenic purpura
When is Fresh frozen plasma transfusion not appropriate
- to use a volume expander in cases of hypovolaemia
- plasma exchange procedures
- treatment of immunodeficiency states
