Blood Transfusions 1 Flashcards
What percentage of pop Is RhD positive?
85%
What RhD blood can RhD+ patients receive
Either -ve or +ve
Although -ve is a waste
What percentage of pop is RhD neg?
15%
What RhD blood can RhD- patients receive
RhD- ONLY
What kind of antibodies develop in RhD cross reaction?
IgG
These are SMALL, so they can cross the PLACENTA
What phenomenon occurs with RhD -ve recepient given RhD +ve blood?
delayed haemolytic transfusion
What antibodies other that ABO D do we look for in a patient?
Kell (K)
Duffy
Kidd (Jk)
What diseases will occur in subsequent pregnancies if RhD-ve mum carries RhD+ child?
Haemolytic disease of the newborn
Hydrops faetalis
How do you group RBC?
Add known anti-A, anti-B, antiD reagents to patients blood cells
If cells agglutinate, this indicates that patient is +ve for that protein
How do you group patient plasma?
Add known A and B group RBC to patient plasma (may have IgM antibodies)
What technique is used for grouping RBC ?
Column agglutination technology
What is the problem with column agglutination technolgy?
That it is impossible To test for all known glycoproteins this way
How does Group and Screen work?
- Mix pt RBC with reagent anti-A/anti-B/anti-D
- Use Indirect Antibody Technique (IAT) - add anti-human Ig (COOMBES ANTIBODIES) to allow bridging of cells
- Check for agglutination
What does group and screen tell you?
It tells you the patients blood type and if the patient has any atypical antibodies
What does a crossmatch tell you?
Whether there is incompatibility between your patient’s blood and the donor blood
How does a full crossmatch work?
Incubate pt plasma with donor RBC
Use IAT
This detects an antibody-antigen reaction that could destroy the RBC leading to extravasc haemolysis
Why are Coombes antibodies added to G&S/Xmatch?
To stimulate cross linking between IgG antibodies and RBC
When is an immediate spin used for crossmatch?
in emergencies
Explain immediate spin
Incubate patient plasma and donor cells for 5 minutes only and SPIN
This will only detect ABO incompatibilityu
Is cross match important if someone is bleeding massively?
NO
Because they lose blood before they are able to make antibodies to it
When can electronic crossmatch be used?
if patient doesn’t have antibodies
How long do donated RBC survive for’
35 days
At what temperature are donated RBC kept
4 degrees
What compatibility needs to be checked for RBC transfusion?
ABO D
plus others
Give O neg in emergency
What compatibility needs to be checked for platelets?
ABO D
Is crossmatch necessary for platelets?
NO
because antigens are only weakly expressed
What compatibility needs to be checked for plasma?
ABO compatibility only
RhD not required
What is the universal plasma?
AB
Because it has no antibodies
When do you need to crossmatch?
If antibodies are present on recipient!!
What Are indications for a transfusion in major haemorrhage?
> 30% blood vol lost
Are autologous transfusions done in UK?
NO
When do you screen for CMV in blood transfusions?
Intra-uterine/neonatal transfusions
Elective transfusions for pregnant women
When do you need to irradiate blood?i
IMMUNOSUPPRESSED PATIENTS
because the patients immune system won’t be able to kill off donor lymphocytes
So donor lymphocytes will attack patient
this will cause GvHD
What classes of people is cell salvage useful in?
Jehovas witness
People with rare blood groups
What type of people do you give washed blood to?
Patients who have had severe allergic reactions to transfusion in the past
what are contraindications for platelet transfusion?
HITT
TTP
What is content of FFP?
Clotting factors, fibrinogen
Anticoagulants (prot C, S, antithrombin, TFPI)
What is the treatment of choice to reverse warfarin?
Prothrombin complex concentrate
contais factors 2,7,9,10
What other substance can be given to reduce bleeding / blood transfusion need in haemorrhage=?
Tranexamic acid
