Haem Flashcards
(89 cards)
What risk assessment is used for stroke prevention (anticoagulants)?
CHA2DS2VASc
What does the CHA2DS2VASc score stand for?
C Congestive heart failure 1
H Hypertension (or treated hypertension) 1
A2 Age >= 75 years 2
Age 65-74 years 1
D Diabetes 1
S2 Prior Stroke, TIA or thromboembolism 2
V Vascular disease (including ischaemic heart disease and peripheral arterial disease) 1
S Sex (female) 1
What must a woman or man score in order to be considered for or offered anticoagulation?
Men - all men with a score = 1 are considered for anticoagulation
Female - women are offered anticoagulation if they have a score >= 2 (women score 1 for being female)
List direct factor Xa inhibitors (anticoaglants)
apixaban, rivaroxaban
What is the reversal agent for factor Xa inhibitor?
andedanex alfa
List direct thrombin inhibitor
dabigatran, argatroban
What is the reversal agent for the direct thrombin inhibitor dabigatran?
idarucizumab
What anticoagulant is used in pregnancy?
heparin rather than warfarin as none teratogenic
What are the 2 different types of heparin available?
unfractionated - contains both LMWH and HMWH
fractionated - contains only LMWH
What is dalteparin (LMWH) mechanism of action?
potentiates antithrombin so increased inhibition of thrombin and factor 10a
preferred over UFH as reduced risk of HIT - UFH also inhibits factor 10
What is the reversal agent for LMWH?
there isn’t one - in an emergency can use protamine (partial reversibility)
What is the reversal agent for UFH?
protamine
What is an important consideration to make when giving unfractionated heparin?
it requires APTR (activated partial thromboplastin time ratio) monitoring
this is because of the risk of HIT (heparin induced thrombocytopenia) - depletion of platelet count over 5-10 days, high risk of thrombosis (due to antibodies interacting with platelets and heparin)
What is the mechanism of action for warfarin?
it reduces the production of vit K dependent factors
inhibits epoxide reductase whoch reduces the production of active vit K (hydroquinone)
therefore, there is a reduction in clotting factors 2, 7, 9 and 10 (and protein C and S)
What is an important consideration to make when administering warfarin to a patient?
they require ongoing monitoring - use INR (PT - extrinsic pathway is important to look at)
PT is sensitive to changes in factor 7 which has the shortest half life
in warfarin patients, their PT should be double a normal patient
What to do with patients on anticoagulation in specific emergencies (high INR, bleeding, urgent surgery)?
- fully reverse the anticoagulant
- if warfarin give vit K
- if heparin or LMWH give protamine
- if dabigatran give idarucizumab
- if factor Xa inhibitor (apixaban, rivaroxaban) give andexanet alfa
- prothrombin complex cocentrate
- fresh frozen plasma
- don’t restart anticoagulants until INR <5
What are the different blood products?
- packed red cells
- fresh frozen plasma
- platelets
- cryoprecipitate
What suspension are red cells contained within in packed red cells?
SAGM ( saline, adenine, glucose, manitol)
Remember GASM
Where do platelet blood products come from?
adult pool of platelets from 4 donors
suspended in the plasma of 1 donor
what does cryoprecipitate contain?
factor 8, VWF, fibrinogen
what are the 4 different blood groups and what antibodies are present in the plasma?
A - contains A antigens, B antibodies
B - contains B antigens, A antibodies
AB - contains A and B antigens, no antibodies
O - contains no antigens, A and B antibodies
which blood group is the universal donor?
group O
which blood group is the universal acceptor?
group AB
what is the rhesus blood group?
describes the presence or absence of rhesus antigen on the surface of RBCs