Haemorrhage

Question 1

Define circulatory shock.

Answer 1

An acute failure of the cardiovascular system to adequately perfuse the tissues of the body

Question 2

What are the 4 types of circulatory shock?

Answer 2

Hypovolaemic
Cardiogenic
Distributive
Obstructive

Question 3

What are some signs and symptoms of shock?

Answer 3

Rapid breathing
Decreased MAP
Impaired urine output
Weak and rapid pulse
Weakened muscle function

Question 4

What is a class I haemorrhage?

Answer 4

10-15% blood loss - no shock, MAP unaffected

Question 5

What is a class II haemorrhage?

Answer 5

Rapid 15-30% blood loss - shock, decreased MAP

Question 6

What is a class III haemorrhage?

Answer 6

Rapid +30% loss - severe shock, major decrease in MAP

Question 7

What happens when blood coagulability is increased?

Answer 7

Production of micro-thrombi
WBC adhesion
Inflammatory response exaggerated

Question 8

How does blood coagulability affect perfusion?

Answer 8

Reduced tissue perfusion and organ failure

Question 9

What happens after hypovolaemia?

Answer 9

Decrease in central venous pressure -> decrease in end diastolic volume -> decrease in stroke volume -> decrease in pulse pressure and MAP -> decrease in baroreceptor activity

Question 10

What do chemoreceptors detect?

Answer 10

Reduction in blood perfusion
Acidosis - low pH

Question 11

What are the three reflex responses?

Answer 11

Increased sympathetic outflow
Vasoconstrictor hormones
Increased renin secretion

Question 12

What does cardiac sympathetic activity, vasopressin and adrenaline cause?

Answer 12

Dilation of coronary arteries and cerebral arteries

Question 13

What are 2 features of the compensated (non-hypotensive) phase?

Answer 13

Loss of up to 15% of blood volume
MAP maintained

Question 14

What are 2 features of the decompensated (hypotensive) phase?

Answer 14

Loss of over 30% of blood volume
MAP falls rapidly

Question 15

What is the immediate cardiac response?

Answer 15

Increased sympathetic outflow
Decreased parasympathetic outflow
Adrenaline secretion
CO increased

Question 16

What is the immediate vascular response?

Answer 16

Increased sympathetic outflow and vasoconstrictor hormones _> TPR and venoconstriction increases
Adrenaline and glucagon stimulate glycogenolysis

Question 17

What are the two intermediate term responses?

Answer 17

Reduced capillary pressure
Stimulation of glycogenolysis

Question 18

What does reduced capillary pressure encourage?

Answer 18

Fluid reabsorption from interstitial fluid

Question 19

What does stimulation of glycogenolysis raise?

Answer 19

Osmolarity of plasma and interstitial fluid
Draws fluid from ICF
Reduced hematocrit

Question 20

What are the 3 long-term responses?

Answer 20

Restoration of water and electrolyte balance
Restoration of plasma proteins
Restoration of haematocrit

Question 21

How is the restoration of water and electrolyte balance achieved?

Answer 21

Increased salt and water reabsorption by aldosterone levels
Increased thirst from angiotensin II levels

Question 22

How is the restoration of plasma proteins achieved?

Answer 22

By the liver

Question 23

How is the restoration of hematocrits achieved?

Answer 23

Kidneys secrete erythropoietin -> triggers RBC production in bone marrow

Question 24

What happens in the decompensated phase (loss of >30%)?

Answer 24

Cardiac failure
CNS depression
Metabolic acidosis of tissues
Death

Question 25

What is a disease associated with haemorrhage?

Answer 25

Cerebral ischemia