Cardiovascular responses to shock

Question 1

Define Shock

Answer 1

An abnormality of the circulatory system resulting in inadequate tissue perfusion and oxygenation

Question 2

What are the 4 different types of shock?

Answer 2

Hypovolaemic (haemorrhagic and non haemorrhagic)
Cardiogenic
Obstructive
Distributive

Question 3

What leads to hypovolaemic shock?

Answer 3

1. loss of blood volume
2. decreased blood volume
3. decreased venous return
4. decreased EDV
5. decreased SV
6. decreased CO and BP
7. inadequate tissue perfusion

Question 4

What leads to cardiogenic shock?

Answer 4

1. decreased cadiac contractility
2. decreased stroke volume
3. decreased CO and BP
4. inadequate tissue perfusion

Question 5

What leads to obstructive shock? ie tension pneumothorax

Answer 5

1. increased intrathoracic pressure
2. decreased venous return
3. decreased EDV
4. decreased SV
5. decreased CO and BP
6. inadequate tissue perfusion

Question 6

What are the 2 types of distributive shock?

Answer 6

• neurogenic shock (spinal cord injury)

- vasoactive shock (septic shock, anaphylactic shock)

Question 7

What leads to neurogenic shock?

Answer 7

1. loss of sympathetic tone
2. massive venous & arteria; vasodilation
3. decreased venous return & SVR
4. decreased CO and BP
5. inadequate tissue perfusion

Question 8

What leasts to vasoactive shock?

Answer 8

1. release of vasoactive mediators
2. massive venous and arterial vasodilation
3. increased capillary permeability
4. decreased venous return and SVR
5. decreased CO and BP
6. inadequate tissue perfusion

Question 9

What are the managements for shock?

Answer 9

ABCDE approach
High flow oxygen
Volume replacement
Inotropes for cardiogenic shock
Immediate chest drain for tension pneumothorax
Adrenaline for anaphylactic shock
Vassopressors for septic shock

Question 10

What happens during haemorrhagic shock?

Answer 10

Compensatory mechanisms can maintain blood pressure until >30% of blood volume is lost