cardiacresponses to shock

Question 1

What is shock?

Answer 1

An abnormality of the circulatory system resulting in inadequate tissue perfusion and oxygenation

Question 2

What are the stages in shock?

Answer 2

• inadequate tissue perfusion
• inadequate tissue oxygenation
• anaerobic metabolism
• acculmualtion of metabolic waste products
• cellular faulire

Question 3

What does adequate tissue perfusion depend on?

Answer 3

Adequate tissue perfusion depends on adequate blood pressure and adequate cardiac output

Question 4

What are the stages in hypovolaemic shock?

Answer 4

• loss of blood volume
• decreased blood volume
• decreased venous return
• decreased end diastolic volume
• decreased stroke volume
• decreased CO and BP
• inadequate tissue perfusion

Question 5

What happens in neurogenic shock?

Answer 5

• loss of sympathetic tone
• massive venous and arterial vasodilation
• decreased venous return and decreased SVR
• decreased cardiac output and decreased BP
• inadequate tissue perfusion

Question 6

What happens in vasoactive (septic) shock?

Answer 6

• release of vasoactive mediators
• massive venous and arterial vasodilation
• increased capillary permeability
• decreased venous return and decreased SVR
• decreased CO and BP
• inadequate tissue perfusion

Question 7

How does hypovolaemia also occur in septic shock?

Answer 7

increased capillary permeability means loss of fluid which means a bit of hypovolaemia

Question 8

What is the outline treatment for shock?

Answer 8

• ABCDE
• high flow oxygen
• volume replacement
• inotropes for cardiogenic shock
• immediate chest drain for tension pneumothorax
• adrenaline for anaphylactic shock
• vasopressors for septic shock

Question 9

What are inotropes?

Answer 9

Drugs that increase cardiac contractility

Question 10

What can cause haemorrhage ?

Answer 10

• trauma
• surgery
• GI haemorrhage

Question 11

How can haemorrhage cause hypovolaemic shock?

Answer 11

• loss of blood volume
• decreased CO
• circulatory shock

Question 12

What else can cause loss of blood volume?

Answer 12

vomiting, diarrhoea, excessive sweating

Question 13

How much blood volume must be lost before compensatory mechanisms can no longer maintain BP?

Answer 13

> 30%

Question 14

What occurs in the acute stage of shock?

Answer 14

Baroreceptor reflex cause compensatory mechanisms such as tachycardia and tachypnoea in the acute stages of shock to increase oxygenation to tissues.

Question 15

What does pulse pressure indicate ?

Answer 15

In acute stages of shock, pulse pressure will decrease even though the BP will be normal

Question 16

What happens when blood loss goes above 30% of blood volume?

Answer 16

• increased pulse
• decreased BP
• decreased pulse pressure
• increased resp rate
• decreased urea output

Question 17

What is the relationship between cerebral blood flow and MAP?

Answer 17

As MAP increased he cerebral blood flow increases slightly but then levels of and remains constant and regulated. cerebral flow only increases again when MAP reaches 180mmHg

Question 18

What is cardiogenic shock?

Answer 18

sustained hypotension caused by decreased cardiac contractility

Question 19

What happens in cardiogenic shock?

Answer 19

• decreased cardiac contractility
• decreased stroke volume
• decreased CO and BP
• inadequate tissue perfusion

Question 20

How does cardiogenic shock affect the Frank-Starling law?

Answer 20

Curve will shift to left as pump can no longer work as well.

Question 21

What happens in obstructive shock? In relation to tension pneumothorax

Answer 21

-increased intrathoracic pressure
-decreased venous return
-decreased end diastolic volume
decreased stroke volume
-decreased CO and decreased BP
-inadequate tissue perfusion

Question 22

Why does decreased intrathoracic pressure decrease venous volume?

Answer 22

If pressure rises within the pleural cavity then pressure rises in right atrium then the venous return wont happen.
Therefore pneumothorax wont just affect the lungs will also affect the heart.