12. Shock Flashcards Preview

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Flashcards in 12. Shock Deck (13)
1

Define shock

An acute condition of inadequate blood flow throughout the body

2

What is mean arterial pressure equal to?

CO x TPR

3

Name 3 causes of cardiogenic shock

Following MI due to left ventricle damage
Serious arrhythmias
Acute worsening of heart failiure

4

What happens in cardiogenic shock?

Heart fills but fails to pump effectively
Central venous pressure rises
Arterial pressure falls
Tissues are poorly perfused (coronary arteries included which exacerbates the situation)

5

Name 2 causes of mechanical shock

Cardiac tamponade
Massive pulmonary embolism

6

What happens in shock caused by cardiac tamponade?

Filling is restricted, end diastolic volume is much smaller
Increase in venous pressure
Decrease in arterial pressure

7

What happens in shock caused by massive pulmonary embolism?

Embolus occludes large pulmonary artery
Pulmonary artery pressure increases
Right ventricle cannot empty
Venous pressure rises
Reduced blood return to left side of heart (left atrial pressure is low)
Arterial pressure is low

7

What percentage of blood must be lost to go into hypovolaemic shock?

30-40%

8

What will a patient in hypovolaemic shock present with?

Tachycardia
Weak pulse
Pale skin
Cold and clammy extremities

9

What happens in toxic shock?

Endotoxins released from bacteria lead to:
Vasodilation (decreased TPR), decreased arterial pressure
Impaired perfusion of vital organs
Capillaries are leaky hence blood volume and venous pressure decrease
The fall in arterial pressure is detected and cardiac output increased

10

How does a patient in toxic shock present?

Tachycardia
Warm and red extremities

11

What happens in anaphylactic shock?

Severe allergic reaction
Release of histamine from mast cells
Drop in TPR and arterial pressure
Sympathetic response increases cardiac output
Impaired perfusion of vital organs
Bronchoconstriction and laryngeal oedema

12

How will a patient with anaphylactic shock present and how do you treat them?

Difficulty breathing
Rapid heart rate
Red and warm extremities

Treat with adrenaline