Blood Groups And Blood Transfusion Flashcards
What is a blood group
Classification of blood based on structures on surface of RBCs
What structures on the surface of RBCs act as antigens
Carbohydrates
Proteins
Glycolipids
Glycoproteins
What determines which antigens are present on an RBC
genes
What are the 2 most clinically important blood group systems
ABO
Rhesus
What are blood group antibodies
Immunoglobulins to RBC surface antigens
What are the 2 types of blood group antibodies
Acquired
Natural
Are natural blood group antibodies innate
No
When are acquired blood group antibodies formed
Immune response to exposure
How are neonates believed to gain natural blood group antibodies
Small amounts of antigens entering body through food, bacteria, and mosquito bites
What happens in the blood antibody- antigen reaction
Antibodies cross link to antigens causing RBC agglutination
What happens when an antibody antigen reaction occurs in vitro
RBC Clumping
What happens when an antibody antigen reaction occurs in vivo
RBC Haemolysis or phagocytosis
What defines a persons ABO blood group
A and B antigens on RBCs
Anti A and anti B antibodies in serum
When do patients have anti A or anti B antibodies in their plasma
When they don’t have the corresponding A or B antigen
How are ABO blood groups inherited
A and B Co dominant
O recessive
Which ABO blood type is the universal donor
Type O
Which ABO blood type is the universal recipient
AB
Which 3 proteins are the most important in the Rhesus system
C D and E
What protein determines rhesus +/- state
D protein
What does Rhesus positive mean
Express immunogenic D antigen
What does Rhesus dpnegative mean
No expression of D antigen
When d genotypes are Rhesus positive
DD or Dd
Which d genotype is Rhesus negative
dd
How does haemolytic disease of the newborn occur
Rh- mother carrying Rh+ baby -> Rh antigens from Cetus enter mothers blood -> mother produces anti Rh antibodies -> anti Rh antibodies attack RBCs of subsequent Rh+ foetus
What blood type mothers and foetuses can haemolytic disease of the newborn occur in
RH- mother
Rh+ feotus
How is haemolytic disease of the newborn prevented
Anti d immunoglobulin administered to mother
How does anti d immunoglobulin prevent haemolytic disease of the newborn
Neutralises RhD positive antigens so mother doesn’t produce antibodies
When is anti d immunoglobulin administered
Risk d antigens have crossed into blood
Routine prophylaxis
Types of blood used for transfusion
Red cells
Platelets
Plasma - fresh frozen, cryoprecipitate, clotting factor concentrates
When are packed red cells used
Haemorrhage
Bone marrow failure
Haemolysis
Inherited Hb disorders
Anaemia
When are platelets used
surgery/invasive procedure w no active bleeding
Stable, non bleeding
What is the most common cause of transfusion mismatch
Transfusion being given to wrong patient
How is blood typed
Plasma mixed with special detector RBCs expressing all common blood group antigens -> plasma antibodies bind to detector RBCs -> positive result = agglutination
What observations are monitored during transfusion
Pulse
Blood pressure
Temp
Which transusion complication is a NHS never event
Acute haemolytic reaction
What causes acute haemolytic reaction
Transfusion of wrong ABO blood type
acute haemolytic reaction
Massive intravascular haemolysis mediated through IgM due to incompatible ABO blood transfusion
Acute haemolytic reaction signs and symptoms
Fever
Abdominal pain
Hypotension
How quickly does acute haemolytic reaction occur
Minutes
Acute haemolytic reaction management
Stop transfusion
Supportive care
Fluid resuscitation
Repeat blood typing, recheck patient and blood details
Non haemolytic febrile reaction
Antibodies react with white cell fragments in transfused blood product and cytokines that have leaked from blood cells during storage
Non haemolytic febrile reaction signs and symptoms
fever
chills
Non haemolytic febrile reaction management
Slow down transfusion
Paracetamol
Blood transfusion minor allergic reaction
Reaction to foreign plasma protein
Transfusion minor allergic reaction signs and symptoms
Pruritus
Urticaria
Transfusion minor allergic reaction management
Temporarily stop transfusion
Antihistamine
Monitoring
Transfusion anaphylaxis cause
Patient with IgA deficiency who has anti IgA antibodies given blood with IgA
What deficiency mediates anaphylaxis from transfusion
IgA
Transfusion anaphylaxis symptoms
Hypotension
Dyspnoea
Wheezing
Angioedema
Anaphylaxis management
IM adrenaline
ABC support
Transfusion associated circulatory overload - TACO
Fluid overload caused by excessive rate of transfusion into pre existing heart failure
Which patients can get TACO
Heart failure patients
TACO signs and symptoms
Pulmonary oedema
Hypertension
TACO management
Slow/stop transfusion
IV Loop diuretic
Oxygen
How does transfusion cause TACO in HF patients
Transfusion increases blood volume
Electrolytes in transfusion cause kidneys to resorb more fluid
Transfusion related acute lung injury - TRALI
Non cardiogenic pulmonary oedema secondary to neutrophil activation
TRALI signs and symptoms
Hypoxia
Pulmonary infiltrates in CXR
Fever
Hypotension
TRALI management
Stop transfusion
Oxygen
Supportive care
How does neutrophil activation cause TRALI
WBC degranulation increases vascular permeability causing inflammation and oedema
Infectious complications of transfusion
Bacterial contamination
Bacterial transmission
Viral transmission
Parasites
Why are RBCs inspected before administration
Check for contamination
