Coagulopathy (Sources: Revision notes)

Question 1

What are the potential aetiologies in ICU patients with coagulopathies?

Answer 1

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

Question 2

How should you approach investigation of coagulopathy in an ICU patient?

Answer 2

Systematic r/v of history and examination
Coagulation screen
D-dimer
FBC and blood film
Bleeding time
B12 and foltate

Question 3

What is the JPAC minimum recommended dose of FFP?

Answer 3

12-15mls/kg

Question 4

What is the ‘INR’ of FFP?

Answer 4

Around 1.6

Question 5

What is cryoprecipitate?

Answer 5

A rich source of fibrinogen

It also contains a significant Von Willebrands component

Question 6

When is cryoprecipitate indicated?

Answer 6

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

Question 7

What is the dose of cryoprecipitate for adults?

Answer 7

2 pooled units

Question 8

What is Octaplex/ prothrombin concentrate?

Answer 8

Freeze dried preparation of clotting factors II, VII, IX, X

Question 9

What are the advantages of prothrombin concentrate?

Answer 9

Easier to store
Longer shelf-life
Smaller volume
Quicker to administer

Question 10

What are the disadvantages of prothrombin concentrate?

Answer 10

Expensive

Smaller volume

Question 11

What is DIC?

Answer 11

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

Question 12

What is the most common cause of DIC?

Answer 12

Sepsis

Question 13

How does DIC manifest clinically?

Answer 13

With bleeding although can present with microthrombi

Question 14

What do lab findings show in DIC?

Answer 14

Hypofibrinoginaemia
Prolonged PT and APTT
Raised D-dimer
Thrombocytopenia

Question 15

How is DIC managed?

Answer 15

Identification and treatment of the underlying cause and transfusion of FFP/plts if significant bleeding is encountered

Question 16

How are aspirin and clopidogrel reversed?

Answer 16

Platelet transfusion

Question 17

How is warfarin reversed?

Answer 17

Vitamin K and FFP reverse within hours

Prothrombin concentrate allows for rapid reversal

Question 18

How are novel oral anticoagulants reversed?

Answer 18

No specific reversal agents

Question 19

How is unfractionated heparin reversed?

Answer 19

Protamine

Question 20

How is LMWH reversed?

Answer 20

Partially reverses with protamine

Question 21

How is fondaparinux reversed?

Answer 21

Nil specific agent

Recombinant factor VII in severe cases

Question 22

Describe the coagulaopthy of liver disease

Answer 22

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

Question 23

What is activated clotting time?

Answer 23

Measure efficacy and guide titration of unfractionated heparin while using extracorporeal circuits

Question 24

What is thromboelastography (TEG)?

Answer 24

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

Question 25

What is rotational thromboelastometry (ROTEM)?

Answer 25

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

Question 26

What is the R time?

Answer 26

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

Question 27

What is clotting time?

Answer 27

ROTEM

Same as R time on TEG

Question 28

What is K time?

Answer 28

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

Question 29

What is the alpha angle?

Answer 29

Angle between a tangent to the tracing at 2mm amplitude and the horizontal midline
Signifies the rapidity of fibrin build up and cross-linking

Question 30

What is maximum amplitude?

Answer 30

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

Question 31

What is CL30?

Answer 31

TEG
Equivalent to LY30 on ROTEM
30% reduction in amplitude 30 mins after MA
Signifies clot stability and fibrinolysis