Blood components Flashcards
What are the 4 main blood components
- Packed red cells
- Platelets
- Fresh frozen plasma
- Cryoprecipitate
Any patient born after 1995 - given non-uk plasma- reduced risk of CJD
How much blood can men and woman donate each year
- Men - Donate 470mls 4x a year
- Women- donate 470mls every 16 weeks (anaemia risk)
- Platelet donors- 24 times a year minimum 14 day interval between each donation
What is the aim of a red cell transfusion and what is given
-Aim to 1) Restore tissue oxygenation 2) Prevent tissue hypoxia
1 UNIT OF RED CELLS =
- 180-200ml packed red cells
- 100ml added solution (normal saline)
- 20ml residual plasma
- Total volume >300ml
- No leukocytes
-Can be stored for 5 weeks at 4 degrees +/- 2
At what haemoglobin level do you transfuse these patients
Under 65 with no co-morbidities
Over 65 with no co-morbidities
Cardiovasc/ cerebrovasc history / co-morbidities
Under 65- Transfuse when Hb less than 70 g/L
Over 65 no co-morbidities - transfuse when Hb less than 80g/L
Cardiovasc/ Cerebrovasc history- Transfuse when Hb is less than 90g/L
At what level of Hb would you transfuse these patients
1) Anaemia symptoms- dyspnoea, angina, palms, tachy, syncope, orthostatic hypotension
2) Evidence of acute bleeding more than 500ml/hr and not stopping
3) Current/ recent (3mnths) marrow failure/ chemo
- Transfuse all of the above when Hb is less than 100
* With anaemia- fatigue is not counted on it’s own as a symptom*
What are the guidelines when choosing red cell volume for transfusion
- Aim to improve the haemoglobin concentration by 20g/L over trigger value for transfusion eg from 70 to 90g/L
- Transfer cells at 4ml/kg will improve it by 10g/L so 8ml/kg will improve it by 20g/L
- Over transfusion= when the correction is more than 20g/L over the trigger
What are the symptoms of transfusion associated circulatory overload and how is it prevented
Symptoms
-Dyspnoea -Orthopnoea -Cyanosis -Tachycardia -HTN -Pul oedema
All within 1-2 hours of transfusion
- Prophylactic diuretics help to prevent
- Occurs in rapid or massive transfusion of patient with chronic anaemia or reduced cardiac reserve
What are the aims to platelet transfusion
To prevent or treat haemorrhage in
1) Thrombocytopenia
2) Platelet function disorders
How are platelets produced for transfusion
2 types
- Pooled platelets- 4 blood donations separated and buffy coats pooled and resuspended in donor plasma - pooled blood has more donor exposure- infection risk
- Apheresis platelets- Platelet rich plasma collected by machine, other blood constituents returned to donor - single donor so lower exposure and infection risk, high yield and greater consistency, HLA/HPA matched donors
What are the constituents of pooled platelets
- 240 X 10 9 platelets
- 250ml plasma
- 60 ml anticoagulant
- Total volume 310 ml
- No leukocytes
- Stored for 5 days @ 22 degrees +/- 2 on agitator rack
- Can be irritated to prevent host reaction
What are the constituents of apheresis platelets?
- 290 X 10 9 Platelets
- 180 ml plasma
- 35ml anticoagulant
- Total vol 215ml
- No leukocytes
-Same storage requirements as pooled
What is the adult therapeutic dose for platelet transfusion
- 1 pack of platelets
- Should increase Plt count by 20 x 10 9
- If platelets don’t increase by 20 on 2 occasions this is called platelet refractoriness - common in multiple transfused patients on haematology ward
What are the circumstance that allow for platelet transfusion
- Haemorrhage prophylaxis when platelets drop below 10
- Thrombocytopenia with haemorrhage
- Disseminated intravascular coagulation
- Massive transfusion
- Plt function disorders
- Cover for surgery/ procedure
What are the contraindications for platelet transfusion
- Thrombocytic thrombocytopenia purpura - blood clots forming in small vessels
- Heparin induced thrombocytopenia- heparin activates immunoglobulins and platelets to make hyper coagulable state
- Idiopathic thrombocytonpenic purpura - abnormal decrease in number of platelets causing easy bleeding and bruising
- Post transfusion purpura - body has produced alloantibodies against the transfused platelets antigens
In ITP and PTP- any platelets that will be transfused will be destroyed by the patients immune system so it is pointless to give them
How is fresh frozen plasma produced for transfusion
- Only taken fro men- as women have also-antibodies
- Prepared for anti-coagulated whole blood
- Patients born after 1995 need treated with methylene blue and removed
- Must be thawed at 37 degrees - if lower a cryoprecipitate may form
