Shock Flashcards
what is shock?
syndrome of inadequate tissue perfusion to meet metabolic requirements
what does normal perfusion require?
cardiac function
vascular bed capacity
circulating blood volume
markers of perfusion
BP
consciousness (brain perfusion)
UO (renal perfusion)
lactate
classification of shock
- hypovolaemic
- cardiogenic
- obstructive
- distributive
- endocrine
causes of hypovolaemic shock
acute haemorrhage
fluid-depleted states (dehydration, burns)
how does hypovolaemic shock caused reduced perfusion?
reduced SVR
reduced cardiac pre-load
reduced CO
what is cardiogenic shock?
reduced CO either due to reduced contractility (SV) or reduced HR
causes of cardiogenic shock
ischaemic dysfunction
cardiomyopathies
valvular damage
dysrhythmias
what is obstructive shock?
mechanical obstruction to normal CO
direct causes of obstructive shock
PE
air/ fat/ amniotic fluid embolism
restriction to cardiac filling causes of obstructive shock
cardiac tamponade
tension pneumothorax
what is distributive shock?
disruption to normal vascular autoregulation and profound vasodilatation
causes of distributive shock
sepsis
anaphylaxis
acute liver failure
spinal cord injuries
causes of endocrine shock
severe uncorrected hypothyroidism
Addison’s
thyrotoxicosis
systems to reverse shock
release of pituitary hormones
cortisol
glucagon
how can shock lead to DIC and reperfusion injuries?
haemodynamic changes can lead to inappropriate activation of coagulation system
presentation of cardiogenic shock
cold clammy hypotension chest pain oedema
presentation of distributive shock
raised JVP
pulsus paradoxus
signs of cause
hypotension
presentation of anaphylactic shock
vasodilation erythema oedema bronchospasm hypotension
presentation of hypovolaemic shock
blood loss tachycardia increased RR reduced UO and GCS hypotension
management of shock
ABCDE
establish wide bore IV access
direct pressure/ tourniquet
fluids
what to be aware of when giving fluids in shock?
beware of overload as susceptible to pulmonary oedema due to microvascular dysfunction
what is the fluid challenge?
rapid administration of fluid with assessment of response
choice of fluids
- crystalloids (water and salts, need large amounts)
- colloids (anaphylaxis risk due to proteins present)
- blood
pharmacological management of shock
adrenaline (alpha and beta agonist) NA (alpha agonist) ADH dopamine dobutamine
mechanical support options
balloon pumps, LVADs, RVADs
ECHMO
side effects of resuscitation
oedema
ARDs
bowel oedema
need to do de-escalation to remove excess fluid
