Blood Products Flashcards
Risks with blood transfusions
Transfusion reactions - quite common even in appropriately cross-matched blood
Blood products are scarce and should therefore only be used when necessary.
Blood group incompatibility is a rare but life-threatening complication. Blood products therefore need to be appropriately cross-matched and checked to avoid severe consequences.
NICE guidelines on indication of blood transfusion.
Hb threshold of 70 g/L for those who need RBC transfusions.
This is without any major haemorrhage or ACS.
Hb conc. of 70-90 g/L after transfusion is the target.
What does RhD+ and RhD- refer to?
The presence or absence respectively of Rhesus D surface antigens on the red bloods cells.
Approx 85% of the population is RhD+
RhD- patient will make RhD antibody if they are given RhD+ blood.
Explain haemolytic disease of the newborn.
A woman is born with RhD- blood. Her partner is RhD+ and she becomes pregnant with a fetus that is also RhD+. During childbirth, she comes into contact with the foetal (Rh+ve) blood and develops antibodies to it.
She later becomes pregnant with a second child that is also Rh +ve.
The woman’s anti-D antibodies cross the placenta during this pregnancy and enter the foetal circulation, which contains RhD+ blood, and bind to the foetus’ RhD antigens on its RBC surface membranes.
This causes the foetal immune system to attack and destroy its own RBCs, leading to foetal anaemia. This is termed haemolytic disease of the newborn (HDN).
What is ABO blood groups?
Presence of A and/or B antigens on the surface of red blood cells.
The ABO group is important for all individual undergoing a potential blood transfusion.
Explain how ABO can give blood.
Explain G&S
Determines the patient’s blood group (ABO and RhD) and screens the blood for any atypical antibodies.
The process takes around 40 minutes and no blood is issued. A G&S is recommended if blood loss is not anticipated, but blood may be required should there be greater blood loss than expected.
Explain crossmatch
Involves physically mixing the patient’s blood with the donor’s blood, in order to see if any immune reaction takes places. If it does not, the donor blood is issued and can be transfused in to the patient.
This process also takes ~40 minutes, in addition to the 40 minutes required to G&S the blood (which must be done first). A X-match is done if blood loss is anticipated, but the surgeon will usually inform you of this.
What is CMV-negative blood products?
CMV is a common congenital infection that may lead to sensorineural deafness and cerebral palsy.
Consequently CMV-negative blood should be given to women during pregnancy, intra-uterine transfusions and to neonates up to 28 days.
What are irradiated blood products?
Blood that is required to reduce the risk of graft-versus-host-disease in at risk populations.
Who should be given irradiated blood products.
Those receiving blood from first or second-degree family members.
Patients with Hodgkin’s Lymphoma
Recent haematopoietic stem cell (HSC) transpants
After Anti-thymocyte globulin (ATG) or Alemtuzumab therapy
Those receiving purine analogues as chemotherapy
Intra-uterine transfusions
If a patient requires more than one unit of blood, how should this be prescribed?
Individually
When should observations be carried out when giving blood.
Before transfusion starts
15-20 minutes after it has started
At 1 hour after
At completion
What cannulas should be used when giving blood products?
Green 18G or Grey 16G cannula
This is because small ones can cause haemolysis by shearing forces.
Types of blood products
Packed Red Cells
Platelets
Fresh Frozen Plasma
Cryoprecipitate
