Coagulopathy (Sources: Revision notes) Flashcards
What are the potential aetiologies in ICU patients with coagulopathies?
DIC Acute coagulopathy of trauma Drugs e.g. warfarin, dabigatran, heparins Liver disease Renal disease Hyper-fibrinolysis Vitamin-K deficiency Acidosis Low ionised calcium Hypothermia
How should you approach investigation of coagulopathy in an ICU patient?
Systematic r/v of history and examination Coagulation screen D-dimer FBC and blood film Bleeding time B12 and foltate
What is the JPAC minimum recommended dose of FFP?
12-15mls/kg
What is the ‘INR’ of FFP?
Around 1.6
What is cryoprecipitate?
A rich source of fibrinogen
It also contains a significant Von Willebrands component
When is cryoprecipitate indicated?
Bleeding with acute DIC or liver disease and fibrinogen < 1.5 g/L
Prior to surgery when fibrinogen < 1.5
In the context of major haemorrhage fibrinogen should be kept > 1.4
What is the dose of cryoprecipitate for adults?
2 pooled units
What is Octaplex/ prothrombin concentrate?
Freeze dried preparation of clotting factors II, VII, IX, X
What are the advantages of prothrombin concentrate?
Easier to store
Longer shelf-life
Smaller volume
Quicker to administer
What are the disadvantages of prothrombin concentrate?
Expensive
Smaller volume
What is DIC?
Defined by the International Society of Thrombosis and Haemostasis (ISTH) as an aqcuired syndrome characterised by the intravascular activation of coagulation with loss of localization arising from different causes
What is the most common cause of DIC?
Sepsis
How does DIC manifest clinically?
With bleeding although can present with microthrombi
What do lab findings show in DIC?
Hypofibrinoginaemia
Prolonged PT and APTT
Raised D-dimer
Thrombocytopenia
How is DIC managed?
Identification and treatment of the underlying cause and transfusion of FFP/plts if significant bleeding is encountered
How are aspirin and clopidogrel reversed?
Platelet transfusion
How is warfarin reversed?
Vitamin K and FFP reverse within hours
Prothrombin concentrate allows for rapid reversal
How are novel oral anticoagulants reversed?
No specific reversal agents
How is unfractionated heparin reversed?
Protamine
How is LMWH reversed?
Partially reverses with protamine
How is fondaparinux reversed?
Nil specific agent
Recombinant factor VII in severe cases
Describe the coagulaopthy of liver disease
Impaired synthetic liver function leads to a reduction in coagulation factors, this is often matched by a decrease in the production of endogenous anticoagulant
Therefore in chronic liver disease a pro-thrombotic tendency exists despite abnormal markers of clotting
In the absence of significant bleeding or thrombocytopenia patients require DVT prophylaxis
What is activated clotting time?
Measure efficacy and guide titration of unfractionated heparin while using extracorporeal circuits
What is thromboelastography (TEG)?
Describes the visco-elastic tendancies of whole blood
Provides information on clot strength, fibrin formation, platelet-fibrin interaction and fibrinolysis
Blood is inserted into 2 cups heated to 37 degrees
The cups then rotate around a wire inserted into the cup, leading to movement of the wire and a characteristic TEG trace is formed.
Kaolin is used to activate clotting
The platelet mapping assay can be added to provide further information regarding platelet function
What is rotational thromboelastometry (ROTEM)?
A visco-elastic test
Similar to TEG but uses and optical system to generate trace
Also uses activators to accelerate clotting
- tissue factor activates the extrinsic pathway
-contact factor activates the intrinsic pathway
What is the R time?
TEG measurement
Time until initiation of fibrin formation
Taken as a period to 2 min amplitude on the tracing
Indicates concentration of soluble clotting factors in the plasma
What is clotting time?
ROTEM
Same as R time on TEG
What is K time?
TEG
Known as clot formation time on the ROTEM
Time period for the amplitude of the tracing to increase from 2 to 20mm
It’s a measurement of clot kinetics
What is the alpha angle?
Angle between a tangent to the tracing at 2mm amplitude and the horizontal midline
Signifies the rapidity of fibrin build up and cross-linking
What is maximum amplitude?
TEG
Equivalent to maximum clot formation on ROTEM
Greatest vertical width achieved by the tracing reflecting maximum clot strength
Signifies number and function of platelets and fibrinogen concentration
What is CL30?
TEG
Equivalent to LY30 on ROTEM
30% reduction in amplitude 30 mins after MA
Signifies clot stability and fibrinolysis
