Lecture 18: Blood and Blood Products Flashcards
Define blood product
Blood product is any product derived from human blood
Define blood component
Blood component is a blood product manufactured in a local blood centre that is derived from a single donation or a small pool (4-6 donations),
This includes red cells, platelets and fresh frozen plasma
(come in bags)
Define plasma derivatives
Plasma derivative is a blood product manufactured from a large pool of plasma donations (1000s) using industrial type systems
(come in bottles)
what are some strategies to maintain safe blood supply?
A number of strategies are employed to maintain safety:
- The use of voluntary and n_on-remunerated_ blood donors
- Research shows that if you introduce incentives (e.g. financial) to blood donation, this can influence the honesty of the donor, and their likelihood to exclude info that may exclude them from being a donor.
- The exclusion of potential donors whose behaviour or lifestyle places them at increased risk of acquiring recognised blood borne viral infections
- The testing of all _blood donations f_or evidence of major blood borne viruses
- The use of physical and chemical methods to destroy any pathogens that may be present.
Considerable evidence exists to demonstrate that a combination of the above measures is more effective than reliance on any one single approach.
Describe the Blood Bourne Infections
Donated blood is a highly effective vehicle for transmission of infection. Blood Services devote considerable effort to reducing the risk. The combination of donor selection/exclusion and testing is more effective than reliance on any single strategy alone.
The table below identifies the main types of infection that can be transmitted by blood components. The list is not exhaustive. (don’t need to know all)
Describe the the 2 reasons why blood donation must be voluntary and non remunerated.
World health assembly 1975 member states were urged to promote the development of national blood services based on voluntary non-remunerated donation of blood
Paid donation associated with:
- Increase risk of blood borne virus transmission
- Donor will fail to reveal behaviour or illness that would normally exclude then from donating blood
- Increase risk that donations will be collected prior to development of positive tests, thus blood collected during this ‘window period’ can be infectious and transmit infection to the recipient even when screening tests are negative
- Exploitation of the poor and disadvantaged
Describe the importance of National Self-Sufficiency
- This involves a country taking active steps to meet requirements for blood and blood products from its own resources (meet its own needs).
- Self-sufficiency prevents exploitation of poorer countries and also reduces reliance on blood products manufactured from paid donor plasma.
What are the NZBS Donor Standards?
1) Selection of blood donors
2) Donor selection aims to protect…
In New Zealand, prospective blood donors:
- Must be between the ages of 16-70 years
- Be in good general health (risk of blood borne infection)
- Are able to donate blood every 12 weeks
- Selection process involves:
- Complete a health questionnaire (national donor questionnaire)
- Lived in UK between the certain time period
- Men who have had sex with other men
- Interview with a registered nurse
- Haemoglobin check
Donor selection aims to protect:
- The potential recipient (identify medical and lifestyle factors that might increase risk of the potential recipient)
- The donor (identify health problems that might increase risk of complications from donation)
What tests are performed on each and every donation?
In New Zealand, the following tests are performed on each and every donation:
- ABO, Rh(D) type and antibody screen
- _Hepatitis B s_urface antigen (HBsAg) and nucleic acid test for HBV DNA
- Hepatitis C antibody and nucleic acid test for HCV RNA
- HIV 1 and 2 antibody and nucleic acid test for HIV-1 RNA
- HTLV antibody (first time donors only)
- Serological test for syphilis
In the event of a positive test, the donor is contacted, counselled and permanently deferred from blood donation.
Describe the residual risk with tested blood
The tests used to screen donated blood are highly sensitive and are capable of detecting the infection soon after exposure.
- Residual risk is the risk of transmission of one of the infections following appropriate donor exclusion and testing.
However, possibility of ‘window period’ transmission still exists.
The table below gives an indication of current window periods and the estimated risk of transmitting the infection by transfusion in New Zealand.
Describe the Informed Consent for Transfusion- by the health and disability code
The New Zealand Health and Disability Code of Consumer’s Rights require:
- Patients to receive information concerning their treatment
- Informed consent to be p_rovided before treatment commences_
The Health and Disability Commissioner has identified that specific informed consent must be obtained prior to transfusion of blood and blood products.
New Zealand Blood Service provides a number of patient information leaflets to support this process.
Describet he Blood processing of Blood Components
Blood component is a blood product manufactured from a s_ingle donation_ or from a small pool comprising 4-6 donations for the purpose of direct transfusion to a patient.
In New Zealand, all blood components are leucodepleted prior to transfusion.
- This involves the r_emoval of white blood cells_ by a process of filtration.
The selection of blood components normally requires:
- Blood group of the recipient to be known;
- May involve specific compatibility testing (cross match procedure in the case of red cells).
1) Centrifuge blood (seperate RBC and plasma and platelets)
2) Add preservative solution to RBC
Describe the
1) Temperature of stoage
2) Shelf life
3) Main clinical indication
of
RBC
- 2-6ºC
- 35 days
- Improve oxygen delivery to tissues in cases of anaemia or blood loss
Describe the
1) Temperature of stoage
2) Shelf life
3) Main clinical indication
of
Platelet concentrations
- 20-24ºC
- 5 days
- To a_void bleeding_ in patients with low platelet counts
Describe the
1) Temperature of stoage
2) Shelf life
3) Main clinical indication
of
Fresh Frozen Plasma
- –25ºC
- 2 years
- Correction of abnormal coagulation in patients who are bleeding
What are the indicators for Red Cell Transfusion?
general factors
specific factors
In deciding whether to transfuse red cells, patient’s haemoglobin (although important) should not be the sole deciding factor.
General factors to consider include:
- Signs and symptoms of hypoxia
- Ongoing blood loss
- The risk of anaemia to the patient
- The risk of transfusion
Specific factors to consider include:
-
Patients cardiopulmonary reserve
- (if pulmonary function is not normal then it may be necessary to consider transfusing at a higher threshold)
-
Volume of blood loss
- Hb level may not be accurate (clinical assessment should attempt to quantify the volume of blood loss before, during and after surgery, to ensure maintenance of normal blood volume)
-
Oxygen consumption
- (may be affected by a number of factors including fever, anaesthesia and shivering; if increased, patients need for red blood cell transfusion could be higher)
- Atherosclerotic disease (critical arterial stenosis to major organs, particularly the heart may modify indications for the use of red cells)
Describe the indications for platelet concentrates transfusion
Transfused in 2 main settings
*See pic
_1) Prophylaxis (_treatment given or action taken to prevent disease.)
- Bone marrow failure
- Surgery/invasive procedure
- Platelet function disorder
2) Patient bleeding
- Bleeding
- Massive haemorrhage/transfusion
Describe the Blood Groups and FFP
What we’re trying to do is ensuring that the plasma that we’re infusing does not contain anti-A or anti-B that can destroy the recipient’s red cells.
So if the recipient is group O, they have neither A or B on their red cells, they can receive plasma from any group
If they are group A, they can have any plasma that does not contain anti-A so they can have A or AB, but they cannot give them plasma froms someone with B, because it’ll have anti-A
People with AB must have plasma from AB
What happens to blood after we donate?
1) NZ blood service separates blood components
2) Plasma taken to CSL
3) They send products back and thy destribute it.
