Cardiovascular Response to Shock Flashcards
what are the 6 types of shock?
1) hypovolaemic
2) cardiogenic
3) obstructive
4) disruptive;
- neurogenic
- vasoactive shock
What may hypovolaemic shock involve?
- haemorrhage
- non-haemorrhage
what may cardiogenic shock involve?
- acute myocardial infarction
what may obstructive shock involve?
- cardiac tamponade
- tension pneumothorax
- pulmonary embolism
- severe aortic stenosis
what may disruptive shock involve?
- neurogenic e.g. spinal cord injury
- vasoactive e.g. septic shock, anaphylactic shock
what is shock?
an abnormality of the circulatory system resulting in inadequate tissue perfusion & oxygenation
what are the 4 steps in-between shock and cellular failure?
1) inadequate tissue perfusion
2) inadequate tissue oxygenation
3) anaerobic metabolism
4) accumulation of metabolic waste products
What 2 things does adequate tissue perfusion depend on?
1) adequate blood pressure
2) adequate cardiac output
what 3 things affect stroke volume?
1) pre-load
2) myocardial contractility
3) afterload
what effects preload?
= venous return
what is hypovolaemic shock?
when you lose more than 20% of your body’s blood supply or body’s fluid
in hypovolaemic shock, what does loss of blood volume cause? (6)
1) decreased blood volume
2) decreased venous return
3) decreased end diastolic volume
4) decreased stroke volume
5) decreased cardiac output & blood pressure
6) inadequate tissue perfusion
what is cardiogenic shock?
sustained hypotension caused by decreased cardiac contractility
what is cardiogenic shock caused by?
= the inability of the heart to pump sufficient blood for the needs of the body.
in cardiogenic shock, what 3 things happen after decreased cardiac contractility?
1) decreased stroke volume
2) decreased cardiac output & blood pressure
6) inadequate tissue perfusion
what happens to the frank starlings curve
- unable to sustain blood pressure
= moving frank starlings curve to the right
what is obstructive shock?
form of shock associated with physical obstruction of the great vessels or the heart itself.
what is a primary example of obstructive shock?
= tension pneumothorax
in a tension pneumothorax in obstructive shock, what 5 events happen after increased intra-thoracic pressure?
1) decreased venous return
2) decreased end diastolic volume
3) decreased stroke volume
4) decreased CO & blood pressure
5) inadequate tissue perfusion
what is neurogenic shock?
= attributed to the disruption of the autonomic pathways within the spinal cord
in neurogenic shock, what 4 things happen after loss of sympathetic tone to blood vessels and heart?
1) massive venous & arterial vasodilation
- effect on heart rate
2) decreased venous return & SVR
- decreased HR
3) decreased cardiac output & blood pressure
4) inadequate tissue perfusion
what happens to the heart rate in neurogenic shock that is unlike other types of shock?
= decreased heart rate
in vasoactive shock, what 4 events happen after the release of vasoactive mediators?
1) massive venous & arterial vasodilation
= increased capillary permeability
2) decreased venous return & SVR
3) decreased CO & BP
4) inadequate tissue perfusion
in vasoactive shock, what 4 events happen after the release of vasoactive mediators?
1) massive venous & arterial vasodilation
= increased capillary permeability
2) decreased venous return & SVR
3) decreased CO & BP
4) inadequate tissue perfusion
what sort of approach should be taken to treat shock?
= ABCDE
what 2 things should be given to treat shock?
1) hig flow oxygen
2) volume replacement
in what type if shock would you NOT give volume placement for?
cardiogenic shock
in cardiogenic shock, what should be given?
inotropes
in a tension pneumothorax, what should immediately be done too avoid obstructive shock?
- chest drain
in anaphylactic shock what should be given?
adrenaline
in septic shock, what should be give?
vasopressors
what are 3 possible causes of hypovolaemic shock?
1) haemorrhage (e.g. trauma, surgery, GI haemorrhage)
2) vomiting or diarrhoea
3) excessive sweating
what effect does vomiting, diarrhoea or excessive sweating have on ECFV?
= decreases ECFV
what happens to blood volume, cardiac output and MAP after a decreased ECFV and what does this cause?
they all decreases
= circulatory shock
= hypovolaemic shock
in haemorrhagic shock, after what percentage of blood volume loss will compensatory mechanisms that are maintaining blood pressure fail?
> 30%
what are the 4 types of haemorrhagic shock?
I
II
III
IV
in haemorrhagic shock, what happens to the heart rate and stroke volume?
= tachycardia (increased heart rate)
= decreased stroke volume
what is the volume pulse like in haemorrhagic shock?
small volume pulse
what does an increased HR and decreased SV have on cardiac output and SVR?
= decreased cardiac output
= increased systemic vascular resistance
what effect does decreased cardiac output & increased SVR have on temperature of peripheries?
cool peripheries
what do all of these things do to MAP?
decreased MAP
