HEMODYNAMICS LECTURE 3: Shock

Question 1

Blood pressure is the product of what?

Answer 1

Cardiac output x Systemic vascular resistance

Question 2

Cardiac output is the product of what?

Answer 2

Heart rate x Stroke volume

Question 3

What 3 factors determine systemic vascular resistance?

Answer 3

1. Blood viscosity
2. Blood vessel length (body size)
3. Vasoconstriction

Question 4

What are the two key signs of shock?

Answer 4

Systemic hypotension and hypoperfusion

Question 5

Which type of shock is due to the heart’s inability to pump blood effectively?

Answer 5

Cardiogenic shock

Question 6

Which type of shock is due to blockage that prevents adequate filling or output?

Answer 6

Obstructive shock

Question 7

What are 2 examples of obstructive shock?

Answer 7

PE, cardiac tamponade

Question 8

Which type of shock is due to a marked drop in blood volume?

Answer 8

Hypovolemic shock

Question 9

Which type of shock involves systemic vasodilation resulting in impaired blood flow?

Answer 9

Distributive shock

Question 10

What are 3 examples of distributive shock?

Answer 10

1. Anaphylactic shock
2. Neurogenic shock
3. Septic shock

Question 11

Why may a brain or spinal cord injury result in neurogenic shock?

Answer 11

Impaired sympathetic nervous system activity leads to vasodilation

Question 12

Why may a type I hypersensitivity reaction result in anaphylactic shock?

Answer 12

Histamine is released, resulting in vasodilation and increased vascular permeability

Question 13

Name the sequence of events that happens as a result of untreated shock

Answer 13

1. Hypoperfusion and cellular hypoxia
2. Production of free radicals, inflammatory cytokines, lactic acid
3. Endothelial damage
4. Increased vascular permeability causing further volume loss
5. Acidosis, hypercoagulability
6. End organ damage and death

Question 14

What are the 3 stages of shock?

Answer 14

1. Non-progressive
2. Progressive
3. Irreversible

Question 15

What is the key difference between the non-progressive and progressive stages?

Answer 15

In the progressive stage the compensatory mechanisms begin to fail

Question 16

What 4 compensatory mechanisms are activated in the non-progressive stage?

Answer 16

1. Vasodilation to maintain perfusion
2. BHP drops to prevent fluid being pushed out of vessels
3. Increased heart rate, contractility, redirection of blood to central organs due to baroreceptors
4. RAA pathway to increase volume

Question 17

In the progressive stage, what 2 things happen in the lungs?

Answer 17

1. Tachypnea, dyspnea, to compensate for hypoxia
2. Pulmonary edema

Question 18

In the progressive stage, what happens in the kidneys?

Answer 18

RAA pathway and vasocontriction lead to oliguria

Question 19

What are 3 things lactic acid buildup leads to?

Answer 19

1. Vasodilation causing blood stasis in capillary beds, this blood becomes hypoxic and coagulative
2. Decreased cardiac output
3. Endothelial injury

Question 20

In the GI system, what are 3 clinical manifestations of shock?

Answer 20

1. Nausea, abdo pain
2. Paralytic ileus
3. GI bleed

Question 21

What are the 2 goals of treating shock?

Answer 21

1. Increase blood pressure
2. Increase urine output

Question 22

Which 2 types of shock have the poorest outcomes?

Answer 22

1. Cardiogenic
2. Septic