Shock

Question 1

What is shock?

Answer 1

• Any condition when blood vessels are not filled and blood cannot circulate normally
• Inadequate blood flow to meet tissue needs
• May result in cell death and organ damage

Question 2

What are the types of shock?

Answer 2

• Hypovolemic shock
• Vascular shock
• Cardiogenic shock
• Obstructive shock
• Transient vascular shock

Question 3

What is hypovolemic shock?

Answer 3

• 30% loss of total blood volume
• Drop in blood volume results in a rapid increase in heart rate and a weak thready pulse
• Intense vasoconstriction to provide blood to vital organs

Question 4

Causes of hypovolemic shock?

Answer 4

• A large scale loss of blood (internal and external)
• Severe vomiting or diarrhoea
• Extensive burns
• Severe dehydration

Question 5

What is vascular shock?

Answer 5

Normal blood volume but poor circulation due to extreme vasodilation resulting in a falling blood pressure

Question 6

Cause of vascular shock?

Answer 6

• Anaphylactic Shock – (allergen), release of histamine and loss of vasomotor tone
• Neurogenic Shock – (sympathetic nerves), failure of the autonomic nervous system
• Septic Shock – (bacterial toxins), septicaemia may cause extreme vasodilation (see next slide)

Question 7

What is cardiogenic shock?

Answer 7

Occurs when the heart is so inefficient, usually due to myocardial infarction, it cannot sustain circulation

Question 8

What is obstructive shock?

Answer 8

Obstruction to blood flow. The most common is pulmonary embolism

Question 9

What is transient vascular shock?

Answer 9

May occur after prolonged sunbathing. Blood vessels dilate in the lower limbs. When standing get pooling of blood in the lower limbs, poor return, drop in BP, and giddiness.

Question 10

What are symptoms of shock?

Answer 10

• Hypotension
• Pale, cool and moist, clammy skin
• Confusion and disorientation due to hypotension
• Increased heart rate
• Decreased urination
• Increased thirst
• Acidosis

Question 11

What are the stages of shock?

Answer 11

1) Compensated stage (Stage I)
2) Progressive stage (Stage II)
3) Irreversible stage (Stage III)

Question 12

What happens in compensated stage (Stage I)?

Answer 12

Homeostatic adjustments (short and long term) cope with shock:

• Short term - Peripheral vasoconstriction and mobilisation of blood reserves to increase blood volume and blood pressure
• Long term - Hormonal release of ADH; renin angiotensin aldosterone system and EPO

Question 13

What happens in progressive stage (Stage ll)?

Answer 13

• Blood volume declines by more than 35%
• Homeostatic mechanisms no longer cope and cardiac output remains inadequate
• Myocardial damage lowers cardiac output more, depriving the body of more oxygen
• BP reaches 50mmHg

Question 14

What happens in irreversible stage (Stage III)?

Answer 14

• Rapid deterioration to a point where death will follow

- Fatal drop in BP & circulatory collapse