Bleeding

Question 1

Mechanism behind head injury -> low BP

Answer 1

• Bleeding
• Acute Brain Injury:

Catecholamine surge:

• alpha: increased pulmonary capillary pressure (through peripheral vasoconstriction/pulmonary venous constriction) -> NPO
• beta: myocardial necrosis: LV Function
• alpha and beta: platelet/micro-emboli -> damaged endothelium -> NPO

All leads to cardiorespiratory compromise

Question 2

ECG changes in SAH?

Answer 2

Q-T prolongation, T wave abnormalities, ST elevation or depression

Question 3

What happens in late haemorrhage?

Answer 3

Late, vasodilatory phase of hemorrhagic shock - attributed to acidotic conditions, adrenaline receptors do not work as well and those that are, are completely saturated.
Also inflame response to trauma -> vasoplegia

Question 4

How to mimic blunt trauma in animals?

Answer 4

7cm liver laceration

Question 5

How to mimic penetrating trauma in animals?

Answer 5

Cannula in femoral artery - bleed out

Question 6

What works regardless of acidotic state?

Answer 6

vasopressin/ADH

splanchnic circulation - gut/fingers peripherally constrict

Question 7

Difficulty with animal studies?

Answer 7

Homogeneity with animal models and anaesthetised/ventilated - this does not represent the period of hypoxia that hemorrhagic shock leads to in real life, i.e. not tissue damage/inflam response to trauma.
Also liver lac not blunt trauma really

Question 8

What might give you a crunchy pelvis that is a confounding sign?

Answer 8

Iliac wing fracture

Question 9

Typical on scene HEMS stuff?

Answer 9

(Ketamine) sedation
Extrication
Anaesthesia
Blood transfusion
Pleural drainage (thoracostomy)
Splintage
Reversal of warfarin
Rapid scene times

Question 10

REBOA zone 1

Answer 10

take-off of the left subclavian artery down to the celiac trunk

Question 11

REBOA zone 2

Answer 11

celiac trunk to the most caudal renal artery.

Question 12

REBOA zone 3

Answer 12

Most caudal renal artery to the bifurcation.

Question 13

CODE red indications?

Answer 13

Systolic BP <90
Poor response to initial fluids
Suspected active haemorrhage

Question 14

What is in pack a?

Answer 14

6 units RBC, 4 units FFP

Question 15

Timing of tranexamic acid?

Answer 15

Optimal if 1g in 1hr
Beneficial if within 3 hours, potentially harmful if after
Maximal effect for SBP <75 mmHg

Question 16

Clues for warfarin?

Answer 16

Yellow book
Medic alert bracelet
Medical notes
AF on ECG
Sternotomy scar / valve click

Question 17

Emergency reversal of warfarin?

Answer 17

Prothrombin Complex concentrate
Contains factors 2, 7, 9, 10
AND protein C and S
Brand names: octaplex/beriplex

Max dose: 3000 IU
Dosing: 1ml/kg
Reconstitute en route to hospital, infuse over 10-20 minutes
Give vitamin K bolus at hospital

Question 18

MOA of Rivaroxaban?

Answer 18

Active direct factor Xa inhibitor

Question 19

MOA of Dabigatran

Answer 19

Direct thrombin inhibitor

Reversed by idarucizumab

Question 20

MOA of Apixaban

Answer 20

Direct factor Xa inhibitor

Question 21

MOA of Tranexamic acid?

Answer 21

Antifibrinolytic

Synthetic analog of amino acid lysine: reversible binding on plasmin. Prevents plasmin from degrading fibrin.

Question 22

What is in FFP?

Answer 22

Fresh frozen plasma:
All coagulation factors

(slightly decreased V and VIII)

Question 23

What is in cryoprecipitate?

Answer 23

aka cryo: plasma replacer
Contains:
fibrinogen
Factor VIII (8)
Von Willebrand factor
Factor XIII (13)
Fibronectin (not useful?)