Blood Groups Flashcards
Describe the three responses to blood loss
- Reducing blood loss through haemostasis
- Increasing production of RBC
- Actions of the sympathetic nervous system
Describe the process of erythropoiesis
Erythropoiesis is the process which produces red blood cells, which is the development from erythropoietic stem cell for mature red blood cell. It is stimulated by decreased O₂ in circulation, which is detected by the kidneys, which then secrete the hormone erythropoietin.
Describe the response of the SNS (sympathetic nervous system) to significant blood loss
INCREASES::
- Heart rate and strength of contraction and cardiac output
- Constriction of veins, venous return and cardiac output
- Peripheral resistance
- Production of adrenaline
What are the three types of blood transfusion?
- Whole blood
- Re-suspended red cells
- Autologous
Describe Whole blood transfusion
Transfusions are indicated when blood loss is rapid and substantial
Describe Re-suspended red cells blood transfusion
Consists of blood with plasma removed and replaced by additive solution
Describe Autologous blood transfusion
Giving a patient a transfusion of their own blood
Why is re-suspended red blood cell blood transfusion used?
For restoring oxygen-carrying capacity from severe blood loss or severe anaemia
Define the term antigen
A substance that is recognised as foreign by the immune system and generates an immune response
Using the ABO classification name the four main blood groups and state what antigens each blood group has
Group A
- A antigens
Group B
- B antigens
Group AB
- A and B antigens
Group O
- Neither A or B antigensFor each of the four blood groups state what antibodies would be present in the plasma
Group A
- B antibody
Group B
- A antibody
Group AB
- Neither A or B antibody
Group O
- Both A and B antibody
State the blood type for universal recipients & explain why this type can receive blood from all blood groups
People with AB positive blood are called “universal recipients” since they do have A, B and antigens, and thus do not have any A, B or antibodies in their plasma
State the blood type that is called the universal donor and explain why this blood type can donate to all blood groups
People with O negative blood are called “universal donors” since they do not have A, B or D antigens, and do have A and B antibodies
Define Blood Typing
Identifying the blood group
Define Cross-matching
The mixing of donor and recipient blood for compatibility
List the six different types of blood transfusion reactions
- Acute haemolytic
- Febrile
- Mild allergic
- Anaphylactic & severe allergic
- Circulatory overload
- Sepsis
Describe what causes an acute haemolytic reaction
Transfusion of incompatible blood transfusion (given the wrong blood type)
Describe what causes a febrile reaction
Reaction and sensitivity to donor WBC, platelets or plasma proteins
Describe what causes a mild allergic reaction
Sensitivity to foreign plasma proteins
Describe what causes an anaphylactic & severe allergic reaction
Sensitivity to foreign plasma proteins
Describe what causes a circulatory overload reaction
Fluid administered faster than circulation can accommodate
Describe what causes a sepsis reaction
Transfusion of bacterially contaminated blood components
Describe the clinical signs & symptoms you would observe if a person had a circulatory overload reaction
- Cough
- Dyspnoea
- Pulmonary congestion
- Headache
- Hypertension
- Tachycardia
- Distended neck veins
What are the two major physiological events that occur during an acute haemolytic reaction
- Agglutination (clumping) of RBC
- Haemolysis of RBC’s
Describe what happens during Agglutination
- Occurs when antibodies attach to a number of RBC’s which are carrying the corresponding antigen
- This causes them to clump together and prevents them to not flow freely
- Obstruction of blood capillaries hindering blood flow to tissues
Describe what happens during Haemolysis
Rupture of RBC’s. Haemoglobin in released into plasma and is trapped in the kidney tubules blocking them, causing acute renal failure and may cause death
Why is an Acute Haemolytic reaction so severe?
- The recipients antibodies attack the antigens on the donors red blood cells
- The recipient will produce antibodies in huge numbers to attack the donor’s RBC’s
Explain what is meant by rhesus positive
People who have the D antigen on RBC surface will be Rhesus positive. They have inherited the Rh factor from either their mother or father
People without the D antigen will be Rhesus negative
What are the three homeostatic responses to blood loss IN ORDER?
- Vasoconstriction (Vascular Spasm)
- Platelet plug formation
- Coagulation (blood clotting)
Function of Vasoconstriction
Narrowing of the blood vessels which helps to restrict blood flow and prevent blood loss
Function of Platelet Plug Formation
Seals the damaged area in the blood vessel temporarily to prevent blood loss
Function of Coagulation?
Formation of a stable clot (liquid to gel) to secure the platelet plug and prevent blood loss. It enables time for tissue to repair
- Clotting factors are activated
