Week 3: Transfusion Medicine Flashcards
Explain compatibility between donors (using antigens and antibodies) - using type O as an example
A type O donor is only compatible with other type O donors, because in their plasma, they contain anti-a and anti-b antibodies. These anti-a and anti-b antibodies will seek and destroy any blood type that is type A,B,AB. Hence, they can only receive type O. However, they can donate their red blood cells to anyone as their redblood cells do not contain antigens. Antigens are basically what are on the blood cell and antibodies detect these antigens. Hence, because Type O has no antigens on their RBC they will not be detected by any antibodies.
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What occurs in a transfusion reaction?
- agglutination of RBCs which causes clumbs which may block small blood vessels.
- The immune system will cause destruction of RBCs means that their contents spills into circulation. Hb contains bilubrin which is toxic in high amounts. Potassium (effects myocytes) and iron which is very toxic.
Transfusion reaction can cause shock and kidney failure.
What are the symptoms of a transfusion reaction?`
- Fever
- Chills
- Rash
- Flank Pain or back pain
- Bloody urine
- Fainting or dizziness
What type of patients need red blood cells and what are their storage requirements and shelf life?
- Patients with severe anaemia whose RBCs do not function adequately
- People with severe bleeding such as accident victims and patients undergoing surgery
- Stored at 2 – 6 degrees Celsius (42-day shelf life, washed RBCs 28 days)
What type of patients need platelets and what are their storage requirements and shelf life?
- Used to help clot blood and seal wounds in surgical and cancer patients
- Some leukaemia and chemotherapy treatments can reduce a patient’s platelet counts
- Issues arise as they must be stored at room temperature which makes it vulnerable to contamination. Stored at 20 – 24 degrees Celsius (5-day shelf life)
What type of patients need plasma and what are their storage requirements and shelf life?
- Plasma contains several proteins, nutrients and clotting factors that help prevent and stop bleeding
- Individual products can be extracted and specifically administered to patients
- Can be Fresh Frozen Plasma (entire plasma) or cryoprecipitate (specific coagulation factors)
- Must be stored at or below -25 degrees Celsius (12-month shelf life)
What blood type is the universal donor for plasma but universal receiver for red blood cells?
AB - as they contain no antibodies in their plasma.
What blood type is the universal donor for red blood cells but universal receiver for plasma?
Type O - as it has no antigens on their red blood cells
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What does Rh positive mean?
The blood cell has the RhD antigen present
What are the 4 types of transfusion reactions?
- Haemolytic reactions (we are focusing on this type this week)
- Are the most serious
- They occur within minutes of the patient receiving the blood
- Usually caused acutely by ABO incompatibility
- This reaction is most severe if Type A RBCs are infused to a group O patient
- Can be caused by errors in labelling, collecting the wrong blood
Not all problems with transfusions are caused by blood type incompatibility
- Allergic reactions
- Someone is allergic to something that is present within the donor’s blood - Bacterial contamination
- If the blood becomes contaminated – common with platelets - Volume overload
- If you give a patient too much blood to quickly they may suffer
- For example, in the lungs it can cause transfusion related acute lung injury
What are some ways we can prevent transfuion reactions and what can you do if you suspect a reaction?
- Patient identity checks, visual inspection of pack, patient obs, type and cross, detailed history.
- The first obvious step is to stop the transfusion
- You then need to manage the patient by treating the symptoms;
- Anti-histamines for allergic reactions
- Blood warmers
- Maintain the airways
- Complete transfusion reaction report form
Anti-A is Type B blood as type B blood contains anti-A antibodies (to destroy A red blood cells)
Anti D are antibodies which are to destroy rhesus positive cells.
Explain what haemolytic disease of a new born is and how it occurs?
incompatibility of RBC types between mother and foetus
When a rhesus negative mother gives birth to a rhesus positive child, the blood from the feotus may come into contact with the mothers immune system. The motheres immune system will develop anti D antibodies. These anti D antibodies may cross into the placenta and therefore, attack the RBCs of the child. However, the blood from the foetus usually comes into contact with the mothers immune system during birth. Hence, it is the 2nd pregnancy that is left with the possible complication of this. It wil be a complication if the 2nd child is rhesus positive. AS the mother may have developed anti d antibodies from the first pregnancy.
