0614 - Shock

Question 1

Define Shock

Answer 1

A state of cardovascular disfunction resulting in generalised inadequacy of oxygen delivery (DO2) RELATIVE to metabolic requirements.

Question 2

What are the four classes of shock?

Answer 2

Hypovolaemic
Cardiogenic
Septic/Vasodilatory
Obstructive

Question 3

What is hypovolaemic shock?

How does the body compensate?

Answer 3

Shock caused by a low volume of blood. Not getting enough blood into heart to give enough preload to get a good stroke volume.

Need to increase HR and vasoconstrict to compensate.

Question 4

What is cardiogenic shock?

How does the body compensate?

Answer 4

Shock caused by failure of heart to pump enough blood out (either too much preload or low contractility) - i.e. low stroke volume.

Need to increase HR and vasoconstrict to compensate

Question 5

What is septic shock?

How does the body compensate?

Answer 5

Shock caused by toxins/cytokines that trigger peripheral vasodilation, reducing SV and BP.

Body struggles to compensate - need to give massive fluids and vasoconstrict.

Question 6

What is obstructive shock?

How does the body compensate?

Answer 6

Shock caused by a deficit in flow to the heart, while enough blood remains in the system. Reduces SV.

Body increases HR to compensate, but need to fix the obstruction.

Question 7

What is the O2 delivery Equation?

Answer 7

DO2 = COx([Hb]xSaO2x1.39) + PaO2x0.003