Shock Flashcards
define shock
an abnormality of the circulatory system resulting in inadequate tissue perfusion and oxygenation
describe the pathway of shock leading to cellular failure
shock inadequate tissue perfusion inadequate tissue oxygenation anaerobic metabolism accumulation of metabolic waste products cellular failure
what does adequate tissue perfusion depend on
adequate blood pressure and adequate cardiac output
describe the pathway of hypovolaemic shock
loss of blood volume decreased blood volume decreased venous return decreased end diastolic volume decreased stroke volume decreased cardiac output and decreased blood pressure inadequate tissue perfusion
name the 4 types of shock
cardiogenic
obstructive
distributive
hypovolemic
what is cardiogenic shock?
sustained hypotension caused by decreased cardiac contractility
describe the pathway of cardiogenic shock
decreased cardiac contractility
decreased SV
decreased CO and decreased BP
inadequate tissue perfusion
describe the pathway of a tension pneumothorax leading to obstructive shock
increased intrathoracic pressure decreased venous return decreased end diastolic volume decreased SV decreased CO and decreased BP inadequate tissue perfusion
describe the pathway of neurogenic shock
loss of sympathetic tone to blood vessels and heart
massive venous and arterial vasodilation
decreased heart rate
decreased venous return and decreased SVR
decreased CO and decreased BP
inadequate tissue perfusion
describe the pathway of vasoactive shock
release of vasoactive mediators
massive venous and arterial vasodilation
increased capillary permeability
decreased venous return and decreased SVR
decreased CO and decreased BP
inadequate tissue perfusion
describe steps in the treatment of shock
ABCDE approach high flow oxygen volume replacement (except for cardiogenic shock) call for help early inotropes for cardiogenic shock immediate chest drain for tension pneumothorax adrenaline for anaphylactic shock vasopressors for septic shock
what happens during haemorrhagic shock?
compensatory mechanisms can maintain blood pressure until more than 30% of blood volume is lost
what causes the small volume pulse in haemorrhagic shock?
tachycardia
increased HR via baroreceptor reflex
decreased SV
what causes the cool peripheries in haemorrhagic shock?
CO may be decreased
increased SVR via baroreceptor reflex
what is the myogenic response?
auto regulation of cerebral blood flow
