Shock

Question 1

define shock

Answer 1

“A syndrome in which tissue perfusion is inadequate for the tissue’s metabolic requirement.”

“A state of cellular and tissue hypoxia due to either reduced oxygen delivery, increased oxygen consumption, inadequate oxygen utilisation,

Question 2

three things normal tissue perfusion relies on

Answer 2

cardiac function

intact and functioning vascular system

circulating blood volume

Question 3

MAP calculation

Answer 3

cardiac output x systemic vascular resistance

Question 4

why is perfusion important

Answer 4

for oxygen delivery

Question 5

4 ways in which shock can be classified

Answer 5

cardiogenic
hypovolemic
obstructive - blockage
distributive
endocrine- 5th

Question 6

hypovolaemic shock cause

Answer 6

acute haemorrhage

due to loss of plasma/ blood volume

Question 7

cardiogenic shock and its causes

Answer 7

pump failure - reduced cardiac output

ischaemia induced myocardial dysfunction , cardiomyopathies, valvular problems and dysrhthmias

Question 8

obstructive shock and causes

Answer 8

Mechanical obstruction
to normal cardiac output
in an otherwise normal heart

causes; PE, tamponade, tension pneumothorax

Question 9

distributive shock and its causes

Answer 9

septic, anaphylaaxis

Due to disruption of normal vascular autoregulation, and profound vasodilatation.

Question 10

endocrine shock causes

Answer 10

Severe uncorrected hypothyroidism, Addisonian crisis – both reduced CO and vasodilation

Question 11

investigations in shock

Answer 11

• Surrogate markers used to measure normal perfusion:
  
  • Blood pressure
  • Consciousness (brain perfusion)
  • Urine output (renal perfusion)
  • Lactate (general tissue perfusion)
• Pulse contour analysis used to measure cardiac output

Question 12

examples of hypovolemic shock

Answer 12

acute haemorrhage, fluid deplete states (severe dehydration, burns)
- Volume depletion leads to reduced SVR
- Reduced volume returning to the heart → reduced pre-load and hence reduced CO

Question 13

common clinical feature in all types of shock

Answer 13

hypotension

Question 14

clinical signs in cardiogenic

Answer 14

signs of myocardial failure

Question 15

signs in obstructive

Answer 15

• Raised JVP
• Pulsus paradoxus
• Signs of cause

Question 16

signs in distributive shock

Answer 16

• Septic: pyrexia, vasodilation, rapid capillary refill
• Anaphalaxis: profound vasodilation, erythema, bronchospasm, oedema

Question 17

signs in hypovolemic

Answer 17

Pale, cold skin, prolonged capillary refill

Question 18

management of hypovolemic shock

Answer 18

• Assessment of bleeding - estimation of volume loss and speed of ongoing loss
• Establish source - may require imaging if stable
• Temporisation - direct pressure, tourniquets
• Damage limitation resuscitation - until definitive control
• Damage limitation surgery

Question 19

what are the mechanical support options

Answer 19

• When drugs fail
• In cardiogenic shock: balloon pumps, L-VADs, R-VADs, VA-ECHMO (severe cases)

Question 20

what is the pharmacological management of shock when fluids dont work

Answer 20

• Adrenaline - alpha/beta adrenergic agonist, at low dose primarily beta (heart rate, contractility, vasodilation)
• Noradrenaline - predominantly alpha agonist
• Others:
  
  • Vasopressin - ADH
  • Dopamine - natural predursor to the above, complex dose-dependent effects
  • Dobutamine/dopexamine - analogues of domapine

Question 21

first management of shock

Answer 21

fluids

Question 22

what is the common end pathway in shock

Answer 22

Cascade of inflammatory mediators as a consequence of cellular ischaemia cause a vicious cycle of vasoconstriction and oedema

Question 23

what are shock patients more susceptible to

Answer 23

pulmonary oedema

Question 24

first choice pharma management in most cases

Answer 24

noradrenaline