Flashcards in Blood Transfusion Deck (42)
What is the process by which whole blood is filtered and white blood cells removed?
What are the main constituents of whole blood?
- Fresh frozen (
What is the process by which the main constituents of whole blood separated?
How much in ml is one unit of RBC?
What are the storage conditions for RBC storage?
4 degrees for up to 35 days
Plasma is removed and replaced by solution of electrolytes, glucose and adenine - keeps RBC healthy
From removal from cold environment, what is the time limit for blood transfusion? How long does it take
Between 1.5-3 hrs
Why do we transfuse patients?
To prevent symptoms of anaemia
Improve quality of life
Prevent ischaemic damage
NOT normalise Hb (Hb conc will remain the same, just number of RBCs will be lower)
What are the symptoms of anaemia the result of?
At what point should a blood transition be given (transfusion threshold)?
The lowest concentration of Hb where symptoms of anaemia are not observed
Name the mechanisms by which the body adapts to anaemia (i.e. maintain tissue oxygenation)?
-Increased cardiac output
-Increased 2,3 DPG
-Increased cardiac artery flow
-Increased EPO production
-Increased O2 extraction
what factors are used to determine the transfusion threshold of patients?
Acute vs chronic - less time for adaptation mechs to develop so termite anaemia less well
Underlying conditions - resp, CV, age - tolerate anaemia less well
Why are RBCs transfused?
To restore oxygen carrying capacity
What are the transfusion thresholds for patients and patients with CV disease who have mild symptoms of anaemia?
When are RBC transfusions to given?
Individuals with preventable causes of anaemia e.g. iron, B12, folate deficiency, renal disease (erythropoietin therapy is choice treatment)
Individual requiring correction of coagulopathy
Which blood loss, what is the amount of blood loss required to necessitate a transfusion?
What is the transfusion threshold level for individuals with chronic anaemia?
Hb 80-100 g/L
- set individual threshold and set Hb concentration targets
What considerations should we have for individuals receiving blood transfusions?
Iron overload - avoid over transfusion
Causes cardiomyopathy and liver failure
What is the transfusion threshold for individuals receiving regular transfusions due to inheritable conditions? What is the objective of this?
Hb 90-95 g/L
- avoid iron overload
- Suppression of endogenous erythropoiesis
What are the optimum storage conditions for plasma?
22 degrees, 5 day shelf life
How long does it take to transfuse plasma?
Why are platelets transfused?
-Prevention of bleeding
What are the contraindications for platelet transfusion?
Heparin induced thrombocytopenia and thrombosis
Thrombotic thrombocytopenia purpura
What are he storage conditions/shelf life for fresh frozen plasma?
- 24 months
- Thawed for 20-30 mins immediately before use
- takes 30 mins to transfuse
How many units does an average adult require?
4-6 units (12-15mg/kg/unit)
What are the main indications for use of fresh frozen plasma?
Coagulopathy with bleeding/surgery
Thrombotic thrombocytopenia purpura
What patients is Fresh frozen plasma not used?
Individuals with warfarin overdose
Individual with single factor deficiency
What are the some special requirements for transfusions?
CMV negative - protect at risk patients from CMV e.g. pregnant women,
Pre trans lab testing. What comprises the group and screen process?
Test donors ABO/Rh(D) group
-Test patient plasma for antibodies against clinically significant blood group antigen
What comprises the pre transfusion lab testing of 'crossmatching?'
Correct donor ABO/Rh groups are selected for patient
Donor blood is mix ed with patient plasma to see if there is any reaction e.g. haemolysis/agglutination
Reaction = incompatible; risk of haemolysis