Blood Products and Transfusions Flashcards
what is considered a ‘blood product’?
any part of the blood that is collected from a donor to use in a transfusion
what is the haemoglobin level at which transfusions can be given?
less than 70g/L hB
what is the target haemoglobin level post-transfusion?
70-90 g/L
what are the two different kinds of blood grouping?
ABO grouping and Rhesus D grouping
what does Rhesus D + refer to?
the patient’s blood group has Rhesus D surface antigens on their RBCs
how does Rhesus D group contribute to haemolytic disease of the newborn?
when a rhesus -ve mother first comes into contact with rhesus antigens, she will make the appropriate antibody but this will not affect her as she is rhesus -ve.
if she is pregnant with a rhesus +ve child, the antibody can cross the placenta and can affect the child leading to foetal anaemia.
what does the ABO group refer to?
it refers to the presence of A and B antigens on the RBCs
true or false: the universal donor O- has no surface antigens
true
true or false: type A blood will carry type A surface antigens
true
what are the two blood tests taken before a transfusion?
group and save (G&S) and cross match (X-match)
what does group and save blood test do?
determines the patients blood group and if there are any irregular antibodies present
what does cross match blood test do?
involves mixing the patient’s blood with donor blood to see if there is any immunological reaction
what are the different kinds of blood products?
- packed red cells
- platelets
- fresh frozen plasma
- cryoprecipitate
what do packed red cells contain?
red blood cells
what are the indications for giving someone packed red cells?
- acute blood loss
- chronic anaemia (hB <70g/L
- symptomatic anaemia
what effect will packed red cells have on a patients blood levels?
1 unit of blood should increase the haemoglobin by 10g/L
what do platelet products contain?
platelets
what are the indications for giving someone a platelet transfusion?
- haemorrhagic shock
- thrombocytopenia (platelets <20 x10^9/L)
- pre-operative platelet level <50 x10^9/L
what effect will the platelet have on a patients blood levels?
1 unit of platelets should increase the platelet levels by 20-40 x10^9/L
what does fresh frozen plasma contain?
clotting factors
what are the indications for giving someone fresh frozen plasma?
- patient has DIC
- any haemorrhage secondary to liver disease
- given after 2nd unit of blood in all massive haemorrhages
what does cryoprecipitate contain?
- fibrinogen
- von Willebrands Factor
- factor VIII
- fibronectin
what are the indications for giving someone cryoprecipitate?
- DIC with fibrinogen at < 1g/L
- von Willebrands Disease
what are the different kinds of post-operative haemorrhage?
- primary bleeding
- reactive bleeding
secondary bleeding
what is ‘primary bleeding’?
bleeding that occurs within the intra-operative period
when should primary bleeding be resolved?
during the operation
what is ‘reactive bleeding’?
bleeding that occurs within 24 hours of the operation
why does reactive bleeding occur?
it may be due to a missed blood vessel or failed ligature as during the operation the patient was vasoconstricted and had low BP
this normalised post-op causing the bleeding to occur
what is ‘secondary bleeding’?
bleeding that occurs 7-10 days post-operatively
why does secondary bleeding occur?
due to an erosion of the vessel because of an infection - it is most commonly seen in heavily contaminated wounds
what are the features of haemorrhagic shock?
tachycardia, dizziness, agitation, visible bleeding, low urine output, tachypnoea
true or false: hypotension is a common sign of haemorrhagic shock
false.
it is often a late sign of haemorrhagic shock
what blood vessel is at most risk of damage during a laparoscopic surgery?
inferior epigastric artery
what is the purpose of thromboprophylaxis?
it is given to patients to reduce the risk of developing a VTE
what are the different kinds of thromboprophylaxis?
mechanical thromboprophylaxis
pharmacological thromboprophylaxis
what is used in mechanical thromboprophylaxis?
- antiembolic stockings
- intermittent pneumatic compression (used in theatre)
what would be a contraindication to mechanical thromboprophylaxis?
should not be used in patients with peripheral arterial disease, peripheral oedema, or local skin conditions
what is used in pharmacological thromboprophylaxis?
enoxaparin injections
what is the classification of enoxaparin?
low molecular weight heparin
true or false: patients with poor renal function should not be given LMWH
true.
they may be given unfractionated heparin instead
what is the mechanism of action for LMWH?
inhibits clotting factors II and X
what is the mechanism of action for unfractionated heparin?
inhibits clotting factors II, VII, IX, X
what is the mechanism of action for warfarin?
inhibits clotting factors synthesised in the liver - II, VII, IX, X by inhibiting vitamin K
why are patients who just start on warfarin are initially hypercoagulable?
because warfarin also inhibits synthesis of protein C, S, and Z which normally regulate clotting
true or false: patients started on warfarin, only need warfarin
false.
they are also given LMWH as they are initially hypercoagulable
