Blood Component Preparation Red Cell Transfusion Flashcards
What are the benefits of dividing blood up into components?
(4)
Ensures maximum use of the blood donation - minimises wastage
Products can be ‘tailor made’ for the underlying clinical disorder e.g. factor deficiencies
Avoids unnecessary volume overload
Different optimal storage conditions for red cells, plasma and platelets
At what temperature should you store red cells
4 degrees Celsius
At what temperature should you store plasma
-20 degrees Celsius
At what temperature should you store platelets?
+22 degrees
List the main blood components
(4)
Red blood cells
White blood cells
Platelets
Frozen plasma
Why do we use centrifugation
By using centrifugation the different densities of blood components allow separation by centrifugation
What are the two types of centrifugation used?
Soft spin
Hard spin
What does a soft spin do?
Separates blood into Plasma rich in platelets and white blood cells and into Red cells
e.g. PRP and RCC
What does a hard spin do?
Separates blood into Plasma poor in platelets, buffy coat and Red cell concentrate
PPP, Buffy Coat and RCC
What is found in the buffy coat?
(4)
Plasma
Platelets
White cells
Red cells
Why might someone have a red cell transfusion
To improve oxygen carrying capacity
Why might someone have a platelet transfusion?
To prevent or stop bleeding
Why might someone have a plasma transfusion?
To replace clotting factors or proteins
Why did we stop using glass bottles and start using plastic
Once the glass bottle was opened the blood could no longer be used as it was no longer sterile
What anti-coagulant do we use?
Citrate
What do we do with freshly donated blood?
Mix it to ensure it is thoroughly mixed with he anti-coagulant
How long does it take to donate blood
About 12 mins, or more accurately 10 minutes
What happens if it takes 15 minutes to donate blood?
This sample won’t be used for platelets as this is too slow
What must you do to the line when the donation is finished?
strip the line to make sure blood in line has also mixed with anti-coagulant
When would you realistically administer plasma
Used in major haemorrhage
Coagulation factors found in plasma help stop bleeding
What is given to patients in America if they have a mass bleed?
Whole blood not plasma and packed red cells
What packs are used for gathering plasma and red cells?
Top and top bags used as we are not gathering platelets
What do you do with the first 20mls of blood in a pack
This is diverted
Why is the first 20mls of blood donated diverted
(2)
There will be a bore of skin in the needle from puncturing the skin
This bore will be in the stream of blood
What do we do with the first 20ml of diverted blood?
Virology testing is carried out on this diverted blood
How do we leukocyte deplete red blood cells
(4)
Use SAG-M additive solution
Leucocyte filter for the red cells
Additive solution is poured through the filter into the red cells -> this primes the filter
Red cells and additive solution is ran through the filter -> leucocyte depleted packed rbcs result
Give three examples of anticoagulant solutions used
ACD
CPD
CPDA-1
What is ACD?
(3)
Acid-citrate-dextrose
Dextrose doesn’t boil so it can be autoclaved while other sugars would make caramael
Used as a preservative in 1945 by the army
What is CPD?
(3)
Citrate-phosphate-dextrose
Phosphate is a buffer
pH stabiliser
What is CPDA-1
CPD with adenine + 25% glucose than CPD
Introduced in 1980 and also used as a storage solution
How does CPDA (Citrate, phosphate, dextrose, adenine) work?
Citrate chelates calcium ions which prevents blood from clotting (anticoagulant)
Phosphate stabilises pH
Dextrose is a nutrient which supports red cell metabolism by maintaining Na/K pump and ATP levels
Adenine - increased nucleotide content leading to high in vivo red cell survival by maintaining ATP
Give three examples of additive solutions
SAGM (sodium chloride adenine glucose mannitol)
AS1-5 (additive solution) - used in USA, if used have to pay royalties, must have similar composition to SAGM
PAGG SM (phosphate adenine glucose guanosine sodium chloride mannitol)
How does SAGM work
(4)
Sodium chloride provides isotonicity
Adenine maintains ATP for cell viability
Glucose supports red cell metabolism
Mannitol helps reduce red cell lysis
How are red cells stored
(6)
Temperature of 4 degrees +- 2 degrees
For 35 days
No agitation is needed
Monitored all the time
Electronic temperature monitor in the fridges
Can be reused if not left out of the fridge for more than 30 mins and if not punctured
How should plasma be stored?
(5)
-20 degrees or below usually below 30
Can be stored for up to 24 months
No agitation needed
Quarantine period in some countries
Cannot be refrozen once thawed for a patient
How should platelets be stored?
(4)
22 degrees +- 2 degrees
7 days
Requires good gas exchange
Must be continually agitated usually on flatbed platelet agitator
Why do we irradiate our platelets?
(3)
Kills DNA material in WBCs
This stops WBCs from reproducing
Prevents graft versus host disease
What is graft versus host disease
(3)
Immunodeficient patient such as chemotherapy patient is give a platelet transfusion containing WBCs
These WBCs will assume they are back in the bone marrow when transfused and will start growing a reproducing
The compromised patient won’t be able to fight back these invading white blood cells
How do we ensure blood doesn’t get left out of fridge for too long?
(3)
Each time product is removed from a fridge it must be scanned
If brought up to theatre the product will be scanned again
If product has been out for more than 30 mins you won’t be able to put it back in the fridge -> system won’t allow it
How long can plasma be left out of the fridge
4 hours
Why do platelets need to be agitated
Platelets are very reactive
Need to be kept agitated so they don’t react
Why do platelets need good gas exchange
(3)
Platelets produce carbon dioxide
This needs to get out of the pack other wise it will form carbonic acid which will alter the pH
We use a breathable plastic to allow this
Write about apheresis
(4)
Donor on machine for up to 4 hours but usually less than 2 hours
Blood goes into the machine
Platelets are removed
Red cells and plasma are returned
What is leukodepletion?
(4)
Removal of white blood cells
Products must contain less than 5x10^6 leucocytes per unit
Buffy coat removal alone will not achieve this
Filtration is now the accepted method of preparation, using ‘third generation’ filters
What is the most efficient way of leucodepletion?
Leucocyte filters remove 99.99%
What are the two types of leucocyte filters?
Red cell filters
Platelet filters
Where can leucofiltration be done?
(3)
At the bedside
In the laboratory before issue
Leucodepletion using in-line filters
How do filters work?
(4)
They utilise cotton wool, cellulose acetate, polyester
WBCs trapped in the small pores and by adherence
Can be influenced by temperature, speed of blood flow and the pre-filtration wbc count
Up to 10-15% loss of the component being processed
How do we irradiate blood?
(4)
Gamma irradiation using caesium or cobalt
25 Gy dose
WBCs unable to divide afterwards
Prevents transfusion associated GVHD
Why would we irradiate products?
(5)
Bone marrow transplant
Congenital immunodeficiency
Premature infants
Intrauterine transfusions
First degree relatives
How is blood frozen
(4)
Glycerol concentration is 40%
Initial freezing is at -80 degrees of -65 degrees
Storage at -65 for 10 years
More common method used
Why would someone need a red cell transfusion
(5)
To increase the oxygen carrying capacity so as to improve tissue oxygenation
Rarely needed if Hb greater than 9 g/dl
Almost always used if Hb less than 6 g/dl
Take into account other factors such as if an old patient has decreased oxygen demand or is on bed rest etc
Follow Maximum Surgical Blood Order Schedule (MSBOS)
When would whole blood transfusion be carried out
Rarely used for allogeneic transfusion, despite supplying most deficits
Restricted to autologous transfusion
When would Red Cells (Leucocyte depleted) be transfused
Product of choice
To increase oxygen carrying capacity without the blood volume expansion of whole blood
What affect will a red cell transfusion have
For ever one unit of red cells transfused there should be a raise in Hb by 1 g/sl
