1- shock

Question 1

what are 3 components that are key for normal tissue perfusion? (just good to have in your brain)

Answer 1

1. cardiac function (heart pumping)
2. intact vascular system (blood vessels)
3. circulating blood

Question 2

what is MAP?

Answer 2

mean arterial pressure = CO x SVR
(cardiac output x systemic vascular resistance)

Question 3

what are the 4 main types of shock?

Answer 3

1. hypovolaemic
2. cardiogenic
3. distributive
4. obstructive

Question 4

what is hypovolaemic shock?

Answer 4

blood loss causing volume depletion leading to reduced SVR, reduced BP and therefore reduced perfusion

causes = acute haemorrhage, fluid depletion (severe dehydration, burns)

Question 5

what is cardiogenic shock?

Answer 5

pump failure, heart not working
- reduced contractility (SV) or reduced HR

causes = mostly ischaemia but could be cardiomyopathies or valvular problems
*if MI then >40% LV involved

Question 6

what is distributive shock?

Answer 6

pipe problem (dilated or constricted) - called hot shock or septic shock

causes = massive dilation of vessel bed from sepsis, anaphylaxis, acute liver failure etc. basically disruption of vasculature causing poor perfusion

Question 7

what is obstructive clot?

Answer 7

blockage in vascular system like blood clot = big block mostly PE’s but can also be air, fat etc

Question 8

what are the classes of shock?

Answer 8

class 1 = <15% blood loss (still feel & look fine, monitor)
class 2 = 15-30% blood loss (low BP)
class 3 = 30-40% (start to get bad, high HR, low pulse pressure, low BP, high RR, low GCS)
class 4 = >40% (very bad, everything low or high, probs unconscious, need blood products)

Question 9

what are clinical signs of shock?

Answer 9

• on examination = pale, cold skin, prolonged cap refill
• urine output (shows renal perfusion)
• neurological - disturbed consciousness (good indicator)
• biochemical stuff like acidosis and lactate levels

Question 10

what is gold standard for measuring cardiac output in specialised units?

Answer 10

thermodilution with PA catheter (inject cold fluid in RA and measure temp)

Question 11

what is management of shock?

Answer 11

• ABCDE
  – IV access
• identify & treat underlying cause
• fluid (replace what’s lost, 20-30ml per kg in sepsis)
• drugs if severe and fluids don’t work e.g. adrenaline, noradrenaline, vasopressins, dopamine
• mechanical support if drugs fail

Question 12

what fluid choices are there?

Answer 12

1. crystalloids (saline) = convenient cheap safe but don’t stay in circulation so need to triple give volume that’s lost e.g. lost 1 litre then need 3L crystalloids
2. colloids (albumin) = cheap ish, reduced volumes required (can cause anaphylaxis, no real benefit →not used much)
3. bloods = carry oxygen and stay in circulation but scare and lots risks

Question 13

what is de-escalation stage (final stage) of shock?

Answer 13

achieve negative fluid balance (need to remove extra fluid once shock resolved)

*can also get puffy and fluid overload after resuscitation