Integrated CV response 2

Question 1

Types of haemorrhages

Answer 1

Revealed=bleeding is obvious although quantity hard to measure accurately
Concealed haemorrhage=e.g. ruptured spleem, fracture femur, renal damage, leaking aortic aneurysm

Question 2

Effect of haemorhage

Answer 2

Chronic slow but persistent=Fe deficiency anaemia

Actue large loss=reduced circulating volume most important aspect is circulatory shock

Question 3

Circualtory shock define

Answer 3

inadequacy of blood flow throughout the body. If prolonged, causes tissue damage becausse insufficient delivery of O2 and other nutrients. NB shock doesn’t just mean low BP

Question 4

Causes of circulatory shock

Answer 4

Haemorrhage, hyppovolumic (burns, severe vomiting/diarrhoea), cardiogenic, anaphylaxis, sepsis

Question 5

Signs of circulatory shock

Answer 5

Temprament (anxiety, restlessness, confusion, agression, lethargy, coma), rapid shallow breathing, intense thirst, nausea, weak pulse/low BP often, grey clammy skin, reduced urine output, acidosis, decreased coagulation time andd increased neutrophils

Question 6

Blood volume per kg male and female

Answer 6

Male: 77ml/kg Female 67ml/kg

Question 7

Haemorrhage classification

Answer 7

minimal: <15% unlikely to elicit shock in fit individual
mild: 20-30% blood loss generally induces shock and BP may be depressed, not usually life threatening
moderate: 30-40% blood loss causes severe shock and profound fall in BP and CO (may become irreversible)
Severe:: >50% blood loss means death is usually inevitable
BUT SEVERITY ALSO RELATED TO SPEED OF BLOOD LOSS

Question 8

Immediate compensation for haemorrhage

Answer 8

Reverse stress relaxation: veins shrink around reduced blood volume->helps maintain venous pressure and therefore venous return
Reflex responses: Increase HR and force, peripheral vasoconstriction, increase sweating
CNS ischaemic response: powerful peripheral vasoconstriction,gut and renal perfusion severely reduced, dangerous if maintained
Activation of RAAS->electrolyte and water retention, vasoconstriction, thirst, increase ADH

Question 9

Draw flow chart of negative feedback of baroreceptor reflex

Answer 9

ref. notes

Question 10

Draw flow chart for more severe blood loss

Answer 10

ref. notes

Question 11

How moderate haemorrhage affects vascular resistance and blood flow of organs around the body and what happens to arterial blood pressure

Answer 11

Vascular resistance: splanchnic, renal, sk. muscle, skin increase, cerebral and coronary normal
Blood flow: splanchnic, renal, sk. muscle, skindecrease, cerebral and coronary norrmal
Arterial BP: nnorrmal (low CO offset by high TPR) but pulse still low

Question 12

Sketch graph for changes in CO and BP as blood is lost

Answer 12

ref. notes CO decreases more rapidly than BP because vasoconstriction by sympathetic to divert CO to key organs and BP more essential for tissue perfusion

Question 13

Methods of restoring volume after haemorrrhage

Answer 13

Internal transfusion (hours) involves moving fluid from interstitium to vascular compartment but cells not regenerated so haemodilution
Increase water intake
Decrease urine production
Increase Na+ and water absorption

Question 14

Internal transfusion mechanism

Answer 14

Hydrostatic pressure in blood decrease and osmolarity of interstitium increases meaning that net flow towards blood

Question 15

Renal mechanism to restore blood vol ddraw flow chart

Answer 15

ref. notes

Question 16

Order of recovery blood components

Answer 16

blood vol, plasma protein, Hb, red cells

Question 17

Why is [Hb] normal immediately after haemorrhage?

Answer 17

Because both the number of RBC and the volume of plasma have fallen to the same extent

Question 18

Why does {Hb] decrease after 12-24 hours after haemorrhage?

Answer 18

Because blood volume restored but RBC not yet recovered=haemodilution

Question 19

What ameliorates reduced oxygen carrying capacity in the first 24 hours

Answer 19

Blood viscosity which favours tissue perfusion

Question 20

Response to haemorrhage

Answer 20

Increased ventilation (decrease blood flow through carotid bodies +/- acidosis due to tissue underperfusion), increased platelet, increase fibrinogen, decrease coagulation time, increase WBC

Question 21

Non progressive shock what

Answer 21

Shock that gets better without treatment (fit person losing under 20% blood e.g. blood donation is around 10%

Question 22

What happens if transfusion is delayed for more than 1 hour

Answer 22

Transfusion vasoconstrictors may only temporarily provide respite before an irrevocable fall in CO due to irretrievable cardiac damages

Question 23

What happens when sustained circulatory failure (draw flow diagram starting with decrease in BP)

Answer 23

multi-organ failure,gut and renal function particularly damaged, risk of acute renal failure and intestinal mucosal damage ref. notes