Hypovolaemia

Question 1

What are the types of shock?

Answer 1

Cardiogenic.
Hypovolaemic.
Obstructive.
Distributive.

Question 2

eg and clinical signs of cardiogenic shock.

Answer 2

MI. ECG, pulmonary and peripheral oedema.

Question 3

eg and clinical signs of hypovolaemic shock

Answer 3

trauma. Dry, empty (weak pulse, cyanosed). Evidence of loss.

Question 4

eg of obstructive shock

Answer 4

DVT, PE.

Question 5

eg and clinical sign of distributive shock

Answer 5

Sepsis. known infection.

Question 6

What is non-progressive stage shock?

Answer 6

normal circulatory responses will rectify without worsening or intervention. (May still need care though!)

Question 7

What is progressive stage of shock?

Answer 7

Compensatory factors cause shock to get progressively worse in a vicious circle. Body tissue deteriorates, necrosis sets in, organ failure, death. Intervention is essential for survival.

Question 8

What is irreversible stage shock?

Answer 8

Progressive shock is at such a stage that intervention will not save the patient. Giving fluids will be progressively ineffective, no matter how much is given.

Question 9

What are the ‘Tennis Scores’ of shock?

Answer 9

Blood loss: 15% - thirsty, CO remains ok.
30% - tachycardia, CO about 50%, but compensatory mechanisms and intervention work.
40% - Irreversible.

Question 10

What are the fast compensatory mechanisms for shock?

Answer 10

Baroreceptor reflex.
Chemoreceptor reflex.
CNS response.

Question 11

What sensory nerve provide feedback for baroreceptor and chemoreceptor reflexes?

Answer 11

Vegus and glossopharyngeal.

Question 12

What stimulates a sympathetic chemoreceptor response?

Answer 12

decreased O2, increased CO2, decreased pH.

Question 13

Where are the baroreceptors?

Answer 13

Aortic arch and carotid.

Question 14

What sympathetic response does the baroreceptor and chemoreceptor reflex trigger?

Answer 14

Vasoconstriction (to maintain return).
Arterial constriction to increase total peripheral resistance (increase BP)
increase HR.

Question 15

What are the intermediate responses to shock?

Answer 15

ADH and renin release

Question 16

Where is ADH release from and what are its main effects in shock compensation?

Answer 16

PPG. vasoconstriction, water retention.

Question 17

What are the main effects of renin in shock compensation, and from where is it released?

Answer 17

JGA in kidney, it converts angiotensinogen into angiotensin, which is then converted into angiotensin II which caused vasoconstriction and inflammation. Angiotensin II also stimulates the release of aldosterone from the adrenal gland which stimulates reabsorption in the kidney DCT.

Question 18

Give e.g. and explain isosmotic expansion

Answer 18

Too much saline.
increase in water and salts into ECF. ECF increases in volume, but osmol remains the same, so no movement of water from ICF to ECF.

Question 19

Give e.g. and explain hyper osmotic expansion

Answer 19

Salt poisoning.
Increase in water and salts into ECF, but too much salt, so water drawn from ICF to ECF: osmol of ECF increases as does vol. ICF vol decreases, so osmol increases.

Question 20

Give e.g. and explain Hyposmotic expansion

Answer 20

Syndrome of Inappropriate ADH.
ADH increases water retention. Too much will cause ECF water retention (increase in ECF volume) and therefore a decrease in ECF osmol. Water is then drawn into ICF so ICF vol also decreases.

Question 21

Give e.g. and explain isosmotic contraction

Answer 21

Severe diarrhoea.
too much water and salt lost. ECF vol decreased, but relative osmol remains constant, therefore no movement of water from ICF to ECF.

Question 22

Give e.g. and explain hyperosmotic contraction

Answer 22

dehydration - loss of water.
increased water loss, but not salt. ECF vol decreases, osmol increases. Water drawn from ICF to ECF so ICF vol also decreased and osmol raised.

Question 23

give e.g. and explain hyposmotic contraction

Answer 23

Too little aldosterone.
Too much salt loss (form decreased reabsorption), normal water loss. ECF decreases osmol, water drawn from ECF to ICF - ICF osmol also decreased.

Question 24

Initial signs of shock

Answer 24

decreased BP
increased HR
tachypnoea
decreased sats
cyanosed
low urinary output

Question 25

How much fluid should be given for hypovolaemia?

Answer 25

20ml/kg stat