Circulatory Shock

Question 1

What is circulatory shock

Answer 1

Profound circulatory failure causing poor perfusion of vital organs

Low BP and it’s physiological consequences

Question 2

what are the 3 main types of circulatory shock

Answer 2

hypovolaemic cardiogenic septic

Question 3

normal blood pressure

Answer 3

arterial pressure 120/80 mm Hg venous pressure is much lower

Question 4

what does normal blood pressure rely on

Answer 4

enough blood in the system (5L)

smooth muscles in vessels having a certain tone heart pumping blood

Question 5

how does the body detect blood flow/BP/oxygen

Answer 5

main detector system is the carotid bodies

2 carotid bodies on either side of the neck - they are innervated so they can send out signals they respond to the pp of oxygen

Question 6

what happens if blood pressure drops (carotid bodies)

Answer 6

pp of oxygen dropscarotid bodies send signals to the brain stem brain stem tells the heart to pump harder and fasterpulse increases

Question 7

brainstem - sympathetic nervous stimulation during low BP

Answer 7

• increased vascular tone in vessels of the limbs and abdomen
• blood pushed up to the chest, keeps vital organs alive
• adrenal glands secrete adrenaline: increased heart rate and strength of contraction
• person sweats and becomes very pale

Question 8

clinical symptoms of circulatory shock

Answer 8

• low BP (e.g. 60/40) combined with fast pulse (>100)

- knowing the normal BP for a person is important

Question 9

hypovolaemic shock

Answer 9

• haemorrhage
• systemic arterial BP normal for a short amount of time then vessels collapse as blood volume decreases
• inferior VC collases, venous pressure falls (~0)
• little blood goes to the lungs, brain and rest of the body
• systemic BP drops - carotid bodies sense lower pp of oxygen
• unregulate symp NS- low BP regulates severe reduction in amount of circulating blood
• treat with blood transfusion

Question 10

cardiogenic shock

Answer 10

• heart failure
• BP falls, pulse rate goes up
• normal venous pressure and return
• heart can’t pump the blood out effectively
• treat with drugs to increase heart function

Question 11

septic shock

Answer 11

• septicaemia
• generalised vasodilation
• pooling of blood in the veins
• not enough blood gets back to the heart (poor venous pressure and filling)
• not enough blood going to brain and rest of the body

Question 12

complications of shock

Answer 12

1. decreased perfusion of brain -> ischaemic infarction of brain tissue is prolonged and untreated
2. decreased perfusion of kidneys –> renal injury (ischaemic necrosis of renal tubules)
3. others