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CLP - Surgery > Shock > Flashcards

Flashcards in Shock Deck (17):
1

definition

acute circulatory failure that compromises tissue perfusion

2

types of shock

hypovolaemic:
haemorrhage - long bones, chest, abdo ,pelvis
dehydration - D+V, DKA (polyuria), burns (losses into blisters/weeping skin), bowel obstruction (third space accumulation)
distributive:
sepsis
anaphylaxis
neurogenic
cardiogenic: direct pump failure
obstructive: indirect pump failure

3

cardiac output

SV x HR

4

BP

CO x SVR

5

MAP

DBP + (SBP - DBP)/3

6

essential features in any kind of shock

fall in BP by at least 40 (SBP<90) (except spinal)
tachycardia (catecholamine release)
tachypnoea (metabolic acidosis caused by tissue hypoxia)

7

hypovolaemic shock

inadequate tissue perfusion and increased sympathetic tone
pt is cold, pale, clammy, poor cap refill
oligo/anuria
rapid thready pulse
narrow PP (vasoconstriction)
regular BP with later hypotension
metabolic acidosis with resp compensation
management: 3Rs

8

cardiogenic shock

signs of myocardial failure
raised JVP
pulsus alterans
gallop rhythm
basal crackles
pulmonary oedema
muffled heart sounds
may not respond to fluid challenge

9

septic shock

flushes, hot, pyrexic, rigors
N+V, sweaty
vasodilation and warm peripheries
rapid bounding pulse
wide PP (vasodilation)
rapid cap refill
loss of BM control
jaundice
coma
rash/meningism
- bacteriaemia, acute pancreatitis, trauma

10

neurogenic shock

no cardiac response
(no increase in HR)
no inhibition of sympathetic outflow

11

anaphylactic shock

profound vasodilation
warm peripheries
low BP
high HR
erythema, urticaria
angio-oedema
pallor, cyanosis
oedema in face or lungs
bronchospasm and hypovolaemia due to cap leak
N+V+D, abdo cramps
management: AAA 1000 100 10

12

effects on cerebral system

regional glucose uptake changes
reflex activity and cortical electrical activity depressed
damage due to cell death
autoregulation over MAP 50-150, but below this pt will become unresponsive, drowsy etc

13

effects on heart

well perfused until late stages - death then occurs quickly
arteries vasodilate causing hypotension
reduced DBP leads to inadequate myocardial perfusion leading to ischaemic chest, pain, arrhythmias, infarction

14

effect on kidneys

neuroendocrine response to hypotension
kidney maintains GFR by selective vasoconstriction and dilation in medulla and cortex
energy dependent filtration can be suspended to conserve O2
prolonged ischaemia causes necrosis of tubular epi
autoregulation of MAP 70-170 - below will be oliguria and impaired renal function

15

effects on lungs and immune system

rarely become ischaemic
amplification of immune response occurs in arteries of lungs
immune complexes and cellular factors aggregate (DIC) in lung
causes immune cell recruitment increased vascular perm and destruction of lung architecture -- ARDS
increased RR due to metabolic acidosis

16

effects on GI

vasocontriction of autonomic splanchnic system occurs early on
first to suffer ischaemia
leads to break down in barrier function
bacteraemia
decreased gut motility and nutrient absorption
infection susceptibility

17

effects on skin

blood supply is centralised, giving cool clammy and mottled peripheral skin