Cardiovascular responses to shock Flashcards
what are the three major different types of shock?
- hypovolaemic
- cardiogenic
- obstructive
- distributive
what are examples of hypovolaemic shock?
haemorrhagic and non-haemorrhagic`
what are examples of cardiogenic shock?
acute MI
what are examples of obstructive shock?
cardiac tamponade, tension pneumothorax, pulmonary embolism, severe aortic stenosis
what are the two types of distributive shock?
neurogenic
vasoactive
what is an example of neurogenic shock?
spinal cord injury
what is an example if vasoactive shock ?
septic shock, anaphylactic shock
what is shock defined as?
an abnormality of the circulatory system resulting in inadequate tissue perfusion and oxygenation
what two factors does adequate tissue perfusion depend on?
adequate blood pressure and adequate cardiac output
what does CO depend on?
SV and HR
what 3 factors impact SV?
preload, myocardial contractility and afterload
what determines the preload?
venous return
what is the sequence of events in hypovolaemic shock ?
- Loss of blood volume
- Decreased blood volume
- Decreased Venous Return
- Decreased End Diastolic Volume
- decreased stroke volume
- decreased CO and BP —>
- inadequate tissue perfusion
what causes cardiogenic shock?
sustained hypotension caused by decreased cardiac contractility
what are the events leading to cardiogenic shock ?
- decreased cardiac contractility —>
- decreased SV - –>
- decreased CO and BP —>
- inadequate tissue perfusion
what are the events leading to tension pneumothorax : obstructive shock?
- increased intrathoracic pressure
- Decreased Venous Return
- Decreased End Diastolic Volume
- decreased stroke volume
- decreased CO and BP —>
- inadequate tissue perfusion
what are the events leading to neurogenic shock ?
- loss of sympathetic tone
- massive arterial and venous vasodilatation
- decreased VR and TPR
- decreased CO and BP —>
- inadequate tissue perfusion
what are the events leading to vasoactive shock ?
- release of vasoactive mediators
- massive venous and arterial vasodilatation - also increased capillary permeability
- decreased VR and TPR
- decreased CO and BP
- inadequate tissue perfusion
what are some general outlines of treatment of shock?
ABCDE approach
high flow oxygen
volume replacement
what should be given for cardiogenic shock?
inotropes as they increase contractility
what should be done for a tension pneumothorax?
immediate chest drain
what should be done for anaphylactic shock ?
given adrenaline
what should be given for septic shock?
vasopressors
what are the haemorrhagic causes of hypovolaemia
trauma, surgery, GI haemorrhage
coughing up blood
what are the non-haemorrhagic causes of hypovolaemia ?
vomiting, diarrhoea, excessive sweating
compensatory mechanisms can maintain blood pressure until…… of blood volume is lost. At this point compensatory mechanisms start to fail
> 30%
look at lecture
plz.
in which organ is there a tight regulation of blood flow?
the cerebrum
how is cerebral blood flow regulated?
through the myogenic response
