Red Cell Transfusion Flashcards
What are our red cell products?
Whole blood
Red Cells Leucocyte Depleted
Partially packed
Washed/Frozen and thawed rbcs
Paedipacks
Talk about whole blood as a product
Rarely used for allogeneic transfusion, despite supplying most deficits
In America it is used in emergencies, especially in the millitary as it contains factors as well etc
Talk about red cells leucocye depleted as a product
The product of choice
Used to increase oxygen carrying capacity without the blood volume expansion of whole blood
What is the expected improvement after a red cell transfusion?
In a typical adult, one unit of red cells is expected to raise the Hb by approximately 1g/dl, or the haematocrit by 3% -> if no bleeding o haemolysis
When might washed/frozen and thawed rbcs be used?
For IgA deficiency -> as patients ill have an anaphyllactic affect to IgA hence need for washed cells
What are the indications for transfion?
Main indication is to increase the oxygen carrying capacity so as to improve tissue oxygenation
It is rarely indicated for a Hb>9g/dl and almot always indicated for a Hb<6g/dl
Other considerations are risk of further blood loss, age of patient, evidence of cardiovascular disease, if patient has decreased oxygen demand, e.g. bed rest etc
Will we always transfuse a Hb of 6?
No if patient has stopped bleeding and the patient has stabilised clinicians will leave it at 6 and not transfuse - they will let it go up on its own once stabilised
However age is an important factor here, a Hb of 6 in an old woman is much more serious than in a young person
Who controls the indications for transfusion
NATA
Network for Advancement of Transfusion Alternatives
What does NATA do?
It reduces transfusion in different cohorts of patients
They found that people can survive on much lower Hb - led to us lowering our cut off for transfusion
They also looked at a lot of studies on cell salvage -> this was funded by Jehovis witnesses
Talk about patient blood management of red cells
One unit transfused at a time as needed (used to be standard practice to give 2)
Not to use a formulaic ordering
Check haemoglobin/Hct between transfusions where possible
Checking PT and APTT, TEG/ROTEM -> if fine then no need for plasma transfusion or clotting factors etc
Regularly update MSBOS
Use alternatives such as cell salvage where approprite
Regular education so staff are aware of the guidelines for use of blood products
Clear protocols for different situations
Use of fibrinolysis inhibitors such as transexamic acid
How can you reduce the need for transfusion prior to surgery?
A lot of people tend to come into hospital already anaemia -> these often need a Hb after surgery -> hence can be treated with iron prior to surgery or opt for keyhole surgery instead
How often is MSBOS determined, why is it so important?
Its agreed upon every year
It tells the clinical staff how many units they should order for each operation
This is the main reason why weve been able to get by with such few donations
What is transexamic acid, how important is it?
Its a fibrinolysis inhibitor
It supports fibrin
It has reduced post maternal haemorrhage deaths by 30%
What are the components of anticoagulants?
Citrate
Sodium biphosphate
Dextrose
Adenine
How does citrate work as a preservative?
It prevents coagulation by chelating calcium
How does sodium biphsophate work as an anticoagulant?
It prevents an excessive drop in pH
How does dextrose work as an anticoagulant?
It supports ATP generation by the glycolytic pathway
How does adenine work as an anticoagulant?
It acts as a substrate for red cell ATP synthesis
What % of red cells must survive post transfusion?
70% viability is the key -> 70% must survive after transfusion, 24 hours post expiry limit
How does mannitol work as a preservative?
Its an osmotic diuretic that acts as a membrane stabiliser
What is the shelf life of CPDA blood?
35 days in Ireland
But 42 days in America
Where do red cells derive most of its energy from?
Energy from the breakdown of glucose to lactate or pyruvate via a sequence of reactions known as the Embden Meyerhof pathway
ATP and 2,3-DPG are the two key compounds produced by this pathway - these are what determine red cell expiry dates and viability
Talk about red cell metabolism in your own words
Anaerobic metabolism
Lactate acid is produced which brings about a pH drop
The more the pH drops the less the red cell can deliver oxygen
2,3-DPG is responsible for pushing oxygen out of the red cell and into tissues
=> the lower the 2,3DPG the less a red cell is able to delliver oxygen to tissue
Talk about the history in the developments in blood storage
In 1914 Payton Rous in NY pioneered combining citrate and glucose to yield a shelf life of 9 days
In 1937 the 1st blood bank in Cook County Hospital in US late
In 1940s Acid Citrate Dextrose was introduced by Mollison
Blood was then stored in glass bottles - autoclaving etc
In 1960s CPD replaced ACD and increased shelf ife to 21 days
From here plastic replaced glass (late 60s), this facilitate separate component production
From the 70s Adenine was introduced increasing shelf life to 35 days
Finally SAGM was introduced increasing shlef life to 42 days in USA but still 35 in Europe
What is meant by the storage lesion?
2,3-DPG levels fall to zero in approximately 2 weeks
The oxygen dissociation cruve shifts to the left
ATP levels also fall to about 50% of initial values
Both ATP and DPG can be regenerated following transfusion
What does 2,3-DPG stand for?
2,3-disphosphoglycerate
Ho long does it take DPG levels to fall to zero?
Only takes 2 weeks
How long does it take to regenerate DPG and ATP in a pack following transfusion?
It only takes 12 to 24 hours for levels to return to normal hence why old blood is perfectly okay for top up transfusions
Why can the storage lesion be dangerous?
Its dangerous in massive transfusion of short dated blood especially in patients with cardiovascular disease
ATP falls and DPG falls -> transfused rbcs wont be able to push out oxygen efficiently
What are the effects of storage on red blood cells, what increases and what decreases?
Increases:
- plasma haemoglobin
- plasma K+
Decreases:
- viable cells
- plasma pH
- plasma Na+
- RBC ATP + 2,3 DPG
What physical changes happen to red blood cells upon storage?
There is a loss of membrane lipids
Haemolysis gradually occurs-usually insignificant
Plasma K+ raised particularly if units are irradiated
Na+ decreased
Both of these changes reflect poor performance at low temperatures of ATPase which acts as a pump for Na and K
Loss of platelets
Loss of labile clotting factors
Change from disc to echinocyte to sphere
What happens to the shape of red blood cells as theyre stored?
Disc to echinocytes/acanthocytes to spheres
As red blood cells change shape their biochemical properties change
This shapae change is not reversible
How are red blood cells stored?
Stored only between 2 and 6 degrees (4 degrees usually) -> refrigerated for 35 days
Temperature monitored with audible alarm systems
Inventory control to minimise blood waste
First in, first out
Re routing especially of O Negs etc
For who shouold blood less than 5 days old be used or and why is this?
Neonates
Cardiovascular surgery
This is due to potassium leakage from cells over time, high potassium can cause cardiac arrest in these patients
Talk about how a blood fridge should be organised
Interior should be well organised and segregated into:
- uncrossmatched blood
- blood being crossmatched
- crossmatched labelled blood
- rejected, outdated or quarantined blood
- autologous blood
What does FIFO sand for?
First in first out
How is massive transfusion defined?
(4)
Replacinement approximating or exceeding the patient’s blood volume within a 24 hour period
An ongoing transfusion requirement in an adult of more than 150ml per minute
Replacement of more than 50% of blood volume in 3 hours or less
Replacement of ones blood volume or transfusion of 10 units or more or red cells in a 24 hour period
What can be some issues with massive transfusions?
Need to have established procedures for emergency provision of blood
Typical issues would be group O rather than ABO specific and these might be stored in satelite locations
Talk about major haemorrhage packs
There are different packs for major haemorrhages e.g. pack 1, pack 2 etc
Different hospitals will have different components in their packs depending on the hospital e.g. for maternity for post partum haemorrhage etc
Talk about the trends in postpartum haemorrhage
The rate of PPH per 100 deliveries have increased in the past 10 years, from 5,0 in 2011 to 8.0/100 in 2018
Talk about trends in major obstetric haemorrhage in Ireland
Trending upwards
was 2.4/1000 in 2011 but now 3.7/1000 in 2018
Talk about trends in transfusions during childbirth over the years
Trending upwards
Was 1.4 in 2011 but no 2.1/100 in 2018
What is the treatment for post partum haemorrhage?
transexamic acid + fibrinogen
What are the five priorities of massive transfusion?
To correct hypovemia with crystalloids -> to prevent tissue perfusion
To optimise the oxygen-carrying capacity of blood
To maintain haemostasis: platelets and coagulation factors
To correct or avoid metabolic disturbances
To maintain intravascular volume with colloids
Why is it important to maintain blood volume during major transfusion?
As if blood volume isnt high enough then organs wont be oxygenated
This will be the case even if Hb is normal
Crystalloids have to be given to expand blood volume
Blood warmers can even be usd when squeezing packs into a person
What are the components of the trauma triad of death?
Hypothermia
Acidosis
Coagulopathy
Explain the trauma triad of death
Hypothemia decreases circulation and thus decreases oxygenation -> anaerobic respiration then leads to lactic acid thus acidosis
Acidosis then causes coagulation to drop significally
In order to treat this coagulopathy you will first have to treat the hypothermia
What are the six acute coagulopathies of trauma
Dilutional coagulopathy
Hypothermic coagulopathy
Platelet dysfunction
Coagulopathy of acidosis
Consumptive coagulopathies
Hyperfibrinolysis
Talk about dilutional coagulopathy
Whereby there is not enough platelets or factors or too many crystalloids
Talk about hypothermic coagulopathy
Coagulation factors are enzymes and these will only work at 37 degrees
These wont work at hypothermic temperatures
Talk about platelet dysfunction in trauma
Platelet dysfunction and activation by tissue factors exposed during trauma
This can lead to DIC
Talk about consumptive coagulopathies
Trauma - tissue factor - too much activation - runs out quickly -> then leads to bleeding in DIC
Talk about hyperfibrinolysis
Overactivation of this can cause problems
How does hypothermia effect platelet function?
Platelet activation by the vWF pathway is gone in 50% of individuals at 30 degrees and profoundly reduced in 75%
How does ph affect factor activity
Normal pH is between 7.35 and 7.45
Saline has a ph of about 5.5
Transfusion brings about a drop in pH
At pH 7 there is less than 50% activity of factors
How do we manage dilutional coagulopathy
Hct of 40% will have Plts of 200,000/mL while a Hct of 20% will have Pts of 50,000/mcL
During transfusion we try to maintain at least 50,000/mcL -> this is actually very low
What causes consumptive coagulopathy?
Massive injury leads to the rapid consumption of coagulation factors
You have only small amounts of coagulation factors in your body
Normal endothelium prevents their activation
Damaged endothelium allows continuous cycles of factor activation and inactivation (consumption)
Talk about uncontrolled fibrinolysis in the massively injured
In the massively injured there is reduced rates of thrombin generation
This leads to thinner fibrin strands with greater surface area
The reduced or absent activation of thombin activatable fibrinolysis inhibitor
Transexamic acid is now used to inhibit this
What causes uncontrolled fibrinolysis in the massively injured?
Reduced or absent activvation of thrombin activatable fibrinolysis inhibitor
How does transexamic acid prevent uncontrolled fibrinolysis?
It strengthens clots by preventing the breakdown of fibres
How do you break the “blood vicious cycle”?
Control haemorrhage
Use best possible resuscitation products
Prevent hypothermia
Prevent haemodilution
Treat coagulopathy
Tranexamic acid
NB: warm patient and warm blood where possible
Why is it important to break the bloody vicious cycle?
This is because even though a patient might have been given enough blood they still might recover if you havent broken the cycle
What is the bloody vicious cycle?
Haemorrhage -> resuscitiation -> haemodilution and hypothermia -> coagulopathy
What must be considered during the emergency release of blood?
RhD positive to RhD negative
Changing blood types during the crisis period
When to switch back to correct group
Blood groups of other products if ABO red cells are non-identical
If plasma or platelet groups have been switched - might have to change red cells to avoid passive antibody problems
What fibrinogen level do you need and why?
Fibrinogen of 4 needed to form clots
When should you switch back from a changed blood group to the correct group?
You should switch back as soon as you get the type of the patient out
This avoids problems in the following days -> its better in the longterm
-> hence why you need a pre-transfusion sample
When might you need the emergenyc release of blood
If patients are rapidle or uncontrollably bleeding they may require immediate transfusion
Group O RhD negative red cells are selected for patients in whom transfusion cannot wait until the ABO and Rh D type of the patient can be determined
Group O RhD positive red cells may be used in specific cases
Where might emergency transfusion take place?
Can take place in any clinical setting from A&E to theatre
Can occur in any hospital
What kind of patients do massive transfusions occur in?
Patients with major trauma
AAA - aortic burst
GI bleeds
Obstetric pateints
Post-parum haemorrhage -> placenta acts as an anti-coagulant normally but after delivery a mother can lose blood quickly if placenta is left in
What are the important steps in dealing with a massive and emergency transfusion?
Prompt action
Good communication
Planned procol that is known by all membors of staff
Make sure everyone is aware
Send for senior help early
Keep records in spite of pressure e.g. telephone requests, emergency sign out sheet etc
Talk about the planned protocol in a massive transfusion
There should be a protocol in place in all hospital
All involved must know about this
Each hospital will have specific needs e.g time to get blood etc
Interventions must be performed according to the protocol and in parallel as appropriate
Talk about the clinical management of massive and emergency transfusion
Provide adequate ventilation and oxygenation
Control the source of haemorrhage
Restore the circulating volume
Start blood component therapy
Maintain or restore normothermia
Evaluate the therapeutic response
Known and implement specific local procedures for dealing with the logistic demands of massive transfusion
How does the laboratory manage massive and emergency trabsfusion
Communication/notification
Emergency O negs
samples required
Blood stocks -> if you think your going to need more blood you should order i
Communication
What are the requirements of emergency O negs
O RhD negs -> must be ABO and RhD confirmed units, available for immediate transfusion
RCLD-SAGM
CMV-
Haemolysin negative
C-
E-
K-
Do emergency O negs have to be irradiated?
No
What product isnt issued by the blood transfusion lab?
Transexamic acid
What considerations have to be made on emergency O negs?
Where are they stored
Labels -> minimum requirements etc
Sign out - will have to be wanded out
Transport -> how is the blood getting to the ward etc
Traceable -> must be fated etc
What samples are required for a emergency transfusion?
Group and crossmatch, pre-transfusion wherever possible
FBC, PT, APTT and fibrinogen
Urea and electrolytes
Thromboelastography
Laboratory tests should be repeated at regular intervals and expert advice obtained where interpretation of results is necessary
What are the transfusion samples labelling requirements
Surname, spelt correctly
Full first nam
Date of birth
Hospital number
Sample must be dated, labelled
Signed by the person takin it
Request form with same details as well as products required and location of patient
What are the labelling requirements of a sample from an unconscious patient?
A unique identified, hospital number if possible
The sex of the patient
Signed by the person taking the sample
How do you issue blood when the only sample available is from an unconscious patient?
Group O blood until a suitable labelled sample is available
What laboratory testing should be carried out on the sample received during an emergency transfusion
Clinical emergency - should be written procedure to follow
ABO and RhD group sample by rapid techniques
Reverse group and/or repeat cell group, using re-sampling or immediate spin crossmatch before issuing ABO matched blood
Antibody screen, if negative no retrospective cross-match required but usually done to be safe
Compatibility report, compatibilty labels and telephone requests
Every hospital will have different packs for emergencies, give an example of a pack 1 and pack 2
Pack 1:
- 6 ORhDneg RCLD
- 2 platelets
- 4 Octaplas
Pack 2:
- 4 ORhDneg RCLD
- 4 Octaplas
- 1 platelet
Fibrinogen and tranexamic acid available as required
Rapid techniques are put in place during emergency transfusion, how does this differ from normal lab testing
Dont need to have a screen completed before issuing ABO compatible blood
Crossmatch doesnt have to be done but labs often do a retrospective crossmatach of any transfused O negs -> usually keep O-ves up on the ward
When should you retest after massive transfusion
After 10 units
Confirmin ABO compatibility
Should return to patient group ASAP
NB: we rarely o beyond using 4 O-s before switching back
How do you deal with antibodies in massive transusions
Posiive antibody screen or history of previous antibodies -> will have to check records and communicate results
Are the antibodies clinically significant?
what other products might be issued during a major haemorrhage
Fresh frozen plasma
Platelets
Fibrinogen/cryoprecipitate/haemocomplettan/Riastap etc
Factor concentrates e.g. factor VIIa
Tranexamic acid
Use of above is usually guided by laboratory results and local policy may be different in each hospitals etc
Talk about factor VIIa during massive haemorrhage
It is pro-coagulative
Its only done in emergency or in surgery
It activates factor 10
Often used alongside tranexamix acid -> pushes along clot formation and then strengthens the clot formed
what are some guidelines for transfusion
PT >1.5. normal
Fibrinogen level of <2g/L
Platelet count <100 c 10^9/L
DIC
who might refuse blood and why?
Jehovah’s witnesses
Their religion doesnt allow thm to receive allogeneic blood or blood products
Talk about local policy and Jehovah’s witnesses
Local policies include a ward of court -> these allow clinicians to transfuse even Jehovahs witnesses
- hospitals are allowed to do this and they will win even if theyre sued
- hospitals can take control if a patient is unconcsious
- but if conscious they can refuse blood
What is 1st, 2nd, 3rd and 4th choices for a group AB recipient?
1st = AB
2nd = A
3rd = B
4th = O
What is 1st, 2nd, 3rd and 4th choices for a group A recipient?
1st choice = A
2nd choice = O
no other blood should be transfused
What is 1st, 2nd, 3rd and 4th choices for a group B recipient?
1st = B
2nd = O
no other blood should be transfused
What is 1st, 2nd, 3rd and 4th choices for a group O recipient?
Only group O should be transfused
What is 1st, 2nd, 3rd and 4th plasma choices for a group AB recipient?
first = AB
second = A
third = B
*A and B must be tested and negative for high tire antibodies
What is 1st, 2nd, 3rd and 4th plasma choices for a group A recipient?
first = A
second = AB
third = B
but A and B must be negative for high titre
What is 1st, 2nd, 3rd and 4th plasma choices for a group B recipient?
first = B
second = AB
third = A
but A and B mist be high titre negative
What is 1st, 2nd, 3rd and 4th plasma choices for a group O recipient?
first = O
second = A
third = B
fourth = AB
Why do we often have to switch groups for plasma?
If first choice isnt available AB is usually your go to but this is usually in short supply so often have to switch groups
Talk about Major ABO incompatibility that occured whereby a recipient O was given donor A
Failure of engrafment: risk not increase in ABOI transplants
Acute haemolysis at the time of reinfusion: avoided by processing donor bone marrow/peripheral blood progenitor cell
Haemolysis of donor-type red cells: avoid by using red cells of recipient type in the early post-transplant period
Delayed erythropoiesis, may be due to persistence of anti-A in the recipient, but minimise transfusion of anti-A by using platelets and plasma from group A donors
Delayed haemolysis due to persistance of recipient anti-A only switch to donor red cells when recipient anti-A undetectable and direct antigobulin test undetectable
Talk about minor ABO incompatibility that occur when a recipient A received donor O
Graft-versus-host disease: risk not increase in ABO-incompatible transplants
Acute haemolysis at the time of reinfusion: avoid bby removing donor plasma if the donor anti-A titire is high
Delayed haemolysis of recipient cells due to anti-A produced by donor lymphoytes: maximum haemolysis usually occurs between days 9 and 16 post-transplant, and occasionally there is severe intravascular haemolysis
What causes major incompatibility
recipint has antibodies against the donation -> can keep producing antibodies
Why is incorrect unit transfused so common in bone marrow transplants?
This is because different components are needed at different times in the difference
It will often be noted in the patient charts what they will get i.e. what point in the transplant they are
What is general ISBT policy during emergency transfusion?
Traceability of all products issued in an emergency is vital - record must be kept
Labelling of samples in a crisis situation
Should only use confirmed units
What is IBTS policy on platelets during emergency?
If switching, group A should preferable receive group B, rather than O and vice versa
How should you get a patients group out quicklyl and confirm units in emergency?
If no historical group is available then an immediate spin forward and reverse group is essential
An acceptable practice is to perform an immediate spin ABO and RhD type on the units prior to release
What should you do if blood has been issued but you havent finished your work up yet?
You should continue the pre-transfusion work up as normal and switch blood groups when required
What should you do with any incompatible units founds at retrospective crossmatch?
Recall any units in cas they havent yet been transfused
