Physiology of Shock Flashcards
what is shock?
inadequate organ perfusion leading to inadequate oxygen delivery to tissues and eventually organ failure
where is the problem in shock?
problem with the heart, blood vessels or the flow of blood
name the types of shock
anaphylactic (distributive) cardiogenic septic hypovolaemic neurogenic
what is distributive shock?
umbrella term for: septic anaphylactic neurogenic - sufficient fluid but in the wrong place
what should you give to restore coagulation factors?
calcium
FSP
CO = _ x _
HR x SV
MAP = _ x _
CO x TPR
what is stroke volume?
volume of blood pumped from the left ventricle per heartbeat
what is TPR?
resistance offered by the systemic vascular circulation
state the oxygen delivery equation
CO x arterial oxygen content (CaO2)
CO is increased in what type of shock?
septic
how can oxygen delivery to tissues be improved in shock?
give a blood transfusion
describe BP and HR in anaphylactic shock
BP reduced profoundly
tachycardia
main pathological process in anaphylactic shock
mast cell degranulation causes release of inflammatory mediators
what type of shock is the only one to cause bradycardia?
neurogenic
what causes bronchoconstriction in anaphylaxis
leukotrienes
prostaglandins
Tx anaphylactic shock
- adrenaline
- IV fluids
- chloramphenamine
- hydrocortisone
why do you need to give IV fluids in anaphylaxis
capillaries are vasodilated and leaky so you need alot of fluid to perfuse it to where you want to go
describe BP and HR in cardiogenic shock
low BP
tachycardia
CO is increased initially increased and then reduces in what type of shock?
septic
skin is swollen and oedematous in what type of shock?
cardiogenic!
what does the skin look like in neurogenic shock?
vasodilated below lesion
what does skin look like in anaphylactic shock?
urticarial rash
when does BP reduce in hypovolaemia?
maintained by compensation then reduces in a late stage
Tx hypovolaemia
fluids
blood replacement
stop bleeding
Tx cardiogenic shock
careful fluid management
inotropes eg dobutamine
vasopressor drugs
Tx septic shock
sepsis 6 eg fluids
vasopressors if fluid unresponsive
give an example of a vasopressor
adrenaline
give an example of an inotrope
dobutamine
Tx neurogenic shock
vasopressors
describe the progression of the skin in septic shock
patient will be flushed and warm and then cool and pale
septic shock tends to be caused by gram _ve bacteria
positive
what is septic shock
dysregulated immune response to infection eg when BP drops below 90/30% drop in systolic
why is lactate measured in sepsis
it is an anaerobic metabolism product because theyre not getting enough oxygen perfusion
why is urine output measured in sepsis
it is a measure of organ function; if the kidney isnt perfused/oxygenated it wont produce urine
most common bacteria to cause sudden death in young adults
GABHS
cause of leaky capillaries and decreased BP in septic shock?
dysfunctional endothelial barrier as a result of bacteria adhering to it
main cause of cardiogenic shock
failure of the heart
cause of neurogenic shock?
loss of sympathetic outflow in thoracic spine leading to lack of feedback
why do patients with septic shock need so many fluids?
capillaries have become extremely leaky
skin appearance in hypovolaemic shock?
cool
pale
how can you improve oxygen delivery in septic shock? name 1st and 2nd line options
- IV fluids
2. vasopressins
if someone is confused and they are septic, what are they thinking of and why?
septic shock
poor perfusion to the brain
describe qSOFA
systolic BP <100mmHg
altered mental status
RR >22
why is heart rate low in neurogenic shock?
sympathetic outflow taken out by an injury so parasympathetics take over by slowing the heart down and vasodilating BVs
name the 2 shockable rhythms
VF
pulseless VT
name the 8 reversible causes of shock
4 Hs 4 Ts hypoxia hypovolaemia hypothermia hyperkalaemia + other metabolic cardiac Tamponade tension pneumo thrombus toxins
