Coordinated CV responses 2

Question 1

What could cause a concealed haemorrhage?

Answer 1

Ruptured spleen, pelvic/femoral fracture etc.

Question 2

How does chronic blood loss present?

Answer 2

As Fe deficient anaemia

Question 3

How does acute blood loss present?

Answer 3

As circulatory shock

Question 4

What are the symptoms of circulatory shock?

Answer 4

Pale (grey/blue) skin, clammy skin, nausea, vomiting, oliguria, intense thirst, rapid + shallow breathing

Question 5

What is circulatory shock?

Answer 5

Generalised inadequacy of blood flow throughout the body

Question 6

What causes circulatory shock?

Answer 6

Haemorrhage, hypovolumic (diarrhoea, vomiting), cardiogenic (acute MI)

Question 7

What is reverse stress relaxation?

Answer 7

When veins shrink around a reduced blood volume to maintain CVP/increase TPR.

Question 8

What are the reflex responses to a low BP following haemorrhage?

Answer 8

Increased TPR (via peripheral vasoconstriction), HR. 
CNS ischaemic response: when systolic BP<50mmHg
which is powerful peripheral vasoconstriction and gut + renal vasoconstriction. 
Activation of the RAAS, leads to increased electrolyte and water retention, more vasoconstriction and thirst.

Summary:
Increased TPR and HP
Ischaemic response (vasoconstriction)
RAAS (thirst + vasoconstriction)