Blood Transfusion Flashcards
Process by which WBCs are removed from a blood transfusion
Leucodepletion
Centrifuged FFP
Cyroprecipitate
Factor concentrates, albumin, immunoglobulins
Fractionation
Antibodies in one individual reacting to cells of another individual
Alloantibodies
A type of haemolysis caused by ABO incompatibility
Intravascular
A type of haemolysis caused by Rh incompatibility
Extravascular
1 unit RBCs is what volume
275ml
How are RBCs stored?
4 degresses for less than 35 days
Purpose of RBC transfusion
To prevent symptoms of anaemia and improve QofL and to prevent damage of end organs in anaemic patients, NOT to normalise the Hb in anaemic patients.
Transfusion threshold trigger
Invest the concentration of Hb that is not associated iwth symptoms of anaemia
Target Hb conc. for anaemic patients
80-100g/dL
Target Hb conc. for patients with inherited anaemias
Aim to suppress endogenous erythropoiesis. Target 100-120g/L
Treatment for anaemia in patients with renal disease
Erythropoietin
How are platelets stored?
room temp. 5 day shelf life.
Adult therapeutic dose of platelety
Platelets from 4 pooled donations or equivalent number from a sinlge apheresis (plasma separated from blood) donation
In what 4 causes would you transfuse platelets?
Severe thrombocytopenia
Massive haemorrhage
Bone marrow failure
Prophylaxis for surgery
Contraindications for platelet transfusion
Heparin induced thrombocytopenia and thrombosis
Thrombotic thrombocytopenic purpura
How is fresh frozen plasma stored?
-30 degrees, for up to 24 months. Thawing takes 20-30 minutes
In what 3 causes would you transfuse someone with FFP
Coagulopathy with bleeding/surgery
Massive haemorrhage
Thrombotic thrombocytopenic purpura
Contraindications for fresh frozen plasma infusion
Warfarin reversal
Replacement of single factor deficiency
A blood transfusion product that contains all the vit. K dependent factors. Used to reverse warfarin over-anticoagulation
Prothrombin complex concentrate
When would you require CMV negative blood transfusions
Children
Why would you need to irradiate blood before transfusion
To prevent graft vs. host disease
Group and Screen
Determines ABO and RH(D) group- plasma screened for antibodies against other clinically significant blood group antigens.
Compatibility testing ‘crossmatching’
Patients plasma is mized with samples of donor RBCs to see if reaction (agglutination or haemolysis) occurs to identify risk of acute haemolysis.
What time scale classes as an acute complication of transfusion
Name 4 acute immunological complications of transfusion
Acute haemolytic transfusion reaction ‘ABO incompatibility’
Allergic reaction
Transfusion related acute lung injury (TRALI)
Febrile non-haemolytic transfusion reaction
Describe the effects of an acute haemolytic reaction
Release of free Hb, deposits in renal tubule
Stimulation of coagulation results in microvascular thrombosis- stimulation of cytokine storm. Scavengers release NO resulting in generalised vasoconstriction
Onset of ABO incompatibility/acute haemolytic reaction
During transfusion
Signs of Acute haemolytic reaction
Fevers/chills, back pain, infusion pain, hypotension/shock, haemoglobinuria, increased bleeding (DIC), chest pain or feeling of impending death
Prognosis for acute haemolytic reaction
fatal in 20-30%
Cause of ABO incompatibility
Always human error
When does a delayed haemolytic reaction occur
3-14 days after RBC transfusion
Clinical features of delayed haemolytic reaction
Fatigue, jaundice and/or fever
Pathological cause of delayed haemolytic reaction
IgG antibodies agains RBC antigens other than ABO. Antibodies are formed after the reaction
Lab findings of delayed haemolytic reaction
low Hb
High LDH
high bilirubin
Test used to confirm haemolysis is due to antibodies on RBCs
Anti-human globulin (Coomb’s test)
Donor has antibodies to recipient’s leucocytes which results in activated WBCs which lodge in pulmonary capillaries and release substances that cause endothelial damage and capillary lead
Transfusion related acute lung injury
Time of onset and prognosis for transfusion related acute lung injury
Occurs within 6 hrs
Majority recover in around 3 days
Treatment for transfusion related acute lung injury
Supportive e.g. oxygen, mechinical ventilation
Symptoms for transufion associated circulatory overload (TACO)
Sudden dyspnoea, orthopneoa, tachycardia, hypertension, hypoxemia
Signs of TACO
increased BP
Increased JVP
2 main types of allergic reactions in transfusion
Urticarial rash with or without wheeze
Anaphylaxis
Acute complication of transfusions which is due to cytokines or biologically active molecules that accumulate during storage of blood components.
Febrile non haemolytic transfusion reactions
Symptoms of febrile non haemolytic transfusion reactions
Fever, rise in temp, shakes/rigor
RBCs broken down in the blood vessels
Intravascular haemolysis
RBCs broken down by macrophages in the liver/spllen
Extravascular haemolysis
Briefly outline the pathology behind thrombotic thrombocytopenic purpura
Don’t have enough of the enzyme required to break down von willebrand factor. Increased VWF in the blood results in the platelets adhering to the surface endothelium more easily, causing microthombi in the small vessels around the body.
