Shock

Question 1

Definition of shock

Answer 1

syndrome in which tissue perfusion not enough for body’s needs

Question 2

Normal tissue perfusion relies on what 3 components?

Answer 2

heart - pump,
vascular bed - pipes,
circulating blood volume

Question 3

Normal perfusion is difficult to measure, but what 4 surrogate markers do we use?

Answer 3

blood pressure,
consciousness,
urine output,
lactate

Question 4

Measuring lactate measures perfusion of what?

Answer 4

General tissue perfusion

Question 5

Measure consciousness measures perfusion of what?

Answer 5

Brain perfusion

Question 6

Measuring urine output measures perfusion of what?

Answer 6

Renal perfusion

Question 7

Mean arterial pressure =

Answer 7

CO x SVR

Question 8

Why is blood pressure not always an accurate measurement of perfusion?

Answer 8

Because body can vary perfusion locally despite relatively constant BP

Question 9

What are the 4(5) causes of shock?

Answer 9

hypovolaemic, 
cardiogenic, 
distributive, 
obstructive, 
(endocrine)

Question 10

Give 3 examples of causes of hypovolaemic shock?

Answer 10

acute haemorrhage (most common),
fluid depletion due to severe dehydration,
burns

Question 11

How does hypovolaemic shock affect the MAP equation?

Answer 11

Volume depletion leads to reduced SVR,

reduced volume returning to heart leads to reduced pre-load so reduced CO

Question 12

How does cardiogenic shock affect the MAP equation?

Answer 12

reduced CO due to reduced contractility (SV) or reduced HR

Question 13

List 4 causes of cardiogenic shock, what is the most common

Answer 13

ischaemia induced myocardial dysfunction (most common),
cardiomyopathies,
valvular problems,
dysrhythmias

Question 14

If cardiogenic shock is due to MI this suggests that >40% of what is involved?

Answer 14

left ventricle

Question 15

Unless correctable pathology such as valve problem, mortality with cardiogenic shock is greater than what?

Answer 15

> 75%

Question 16

What is obstructive shock?

Answer 16

Mechanical obstruction to normal cardiac output in otherwise normal healthy heart

Question 17

What are two causes of obstructive shock? give two examples of each

Answer 17

direct obstruction to CO e.g. PE, air/fat/amniotic fluid embolism,
restriction of cardiac filling e.g. tamponade, tension pneumothorax

Question 18

Distributive shock AKA vasoplegic is known as what kind of shock

Answer 18

“hot” shock

Question 19

List 4 causes of distributive shock

Answer 19

sepsis,
anaphylaxis,
acute liver failure,
spinal cord injuries

Question 20

What happens in distributive shock?

Answer 20

due to disruption of normal vascular auto regulation and profound vasodilatation

Question 21

What does it mean that there are regional perfusion differences in someone in distributive shock?

Answer 21

They may be awake and talking but some organs are not getting perfused

Question 22

What happens in terms of CO and vasodilatation/constriction in endocrine shock?

Answer 22

Reduced CO and vasodilation

Question 23

What causes endocrine shock? (3)

Answer 23

severe uncorrected hypothyroidism,
addisonian crisis,
thyrotoxicosis

Question 24

List 4 types of shock in order of most common to least

Answer 24

distributive shock, (septic) 
cardiogenic, 
hypovolaemic, 
distributive (nonseptic), 
obstructive

Question 25

List 2 types of response to shock

Answer 25

sympathy-adrenal response, | neuroendocrine response

Question 26

List 5 hormones that are released in shock

Answer 26

``` ACTH, ADH, endogenous opioids, cortisol, glucagon ```

Question 27

What does cortisol release do in shock (2)

Answer 27

fluid retention, | antagonises insulin

Question 28

Inflammatory response in shock can occur as part of pathological process or consequences of and often both. Give example of pathological process its a part of and an example of a situation in which It is a consequence

Answer 28

pathological process - sepsis, | consequence of persisting hypo perfusion

Question 29

List 7 components of inflammatory response

Answer 29

activation of complement cascade, cytokine release, platelet activating factor, lysosomal enzymes, adhesion molecules, endothelium derived mediators (e.g. nitric oxide), imbalance between antioxidants and oxidants

Question 30

What does activation of complement cascade in inflammatory response cause?

Answer 30

attraction and activation of leucocytes

Question 31

What does release of platelet activating factor in inflammatory response cause? (2)

Answer 31

increased vascular permeability (leaky), | platelet aggregation

Question 32

What does release of lysosomal enzymes in inflammatory response cause? (2)

Answer 32

myocardial depression, | coronary vasoconstriction

Question 33

List 5 haemodynamic changes in shock

Answer 33

vascular abnormalities (dilation or constriction), distribution of of blood flow messed up, microcirculatory abnormalities (capillary beds flow interrupted), inappropriate activation of coagulation systemic -> DIC, reperfusion injuries

Question 34

The loss of vascular reactivity (failure of vascular smooth muscle constriction) in shock is mostly caused by what?

Answer 34

Huge increase in release of nitric oxide

Question 35

Myocardial dysfunction in shock is mostly caused by reduced coronary blood flow. T/F?

Answer 35

False!! its caused by cytokines on myocardium, beta receptor down regulation, decreased cardiomyofilament calcium sensitivity

Question 36

What symptom is almost always present in all types of shock?

Answer 36

Hypotension (usually)

Question 37

Cardiogenic shock presentation (5)

Answer 37

``` cold, clammy, chest pain, oedema, not very tachycardic ```

Question 38

Distributive shock presentation (3)

Answer 38

raised JVP, pulsus paradoxus, signs of cause

Question 39

Distributive shock septic presentation (4)

Answer 39

``` pyrexia, vasodilatation, rapid cap. refill, warm and red hypotension ```

Question 40

Distributive shock anaphylaxis presentation (4)

Answer 40

profound vasodilatation, erythema, bronchospasm, oedema

Question 41

Assessment of shock (7)

Answer 41

``` exam (skin temp, CRP), blood pressure monitoring, pulse contour analysis for CO, urine output, neurological, acidosis, lactate levels ```

Question 42

Gold standard management for monitoring cardiac output?

Answer 42

thermodilution with a PA catheter but no one really happens

Question 43

Management of shock

Answer 43

ABCDE, wide bore IV access and treat underlying cause, fluids, noradrenaline

Question 44

Biggest components of oxygen delivery (3) and how does this affect treatment aims

Answer 44

``` Hb, SpO2, CO Hb -> correct anaemia, ensure O2 normal, optimise CO ```

Question 45

Why should you be careful with fluids in shocked patients

Answer 45

shocked patients more susceptible to pulmonary oedema due to microvascular dysfunction

Question 46

Typical fluids for shock

Answer 46

300-500ml over 10-20 mins

Question 47

MAP range target? but can vary depending on clinical picture

Answer 47

65-75

Question 48

Pros and cons of crystalloids

Answer 48

convenient cheap and safe, but rapidly lost from circulation

Question 49

Pros and cons of colloids

Answer 49

can cause anaphylaxis

Question 50

What does noradrenaline do

Answer 50

predominantly alpha agonist so vasoconstrictions

Question 51

Cardiogenic shock severe when drugs fail

Answer 51

balloon pumps, L-VADs, R-VADs severe: VA-ECMO

Question 52

``` Shock of blood loss <15% HR, BP, Cap refill, UO ml/hr, Mental state ```

Answer 52

``` HR <100, BP normal, Cap refill normal, UO ml/hr >30, Mental state normal ```

Question 53

``` Shock of blood loss 15-30% HR, BP, Cap refill, UO ml/hr, Mental state ```

Answer 53

``` HR >100, BP normal, Cap refill >2sec, UO ml/hr 20-30, Mental state anxious ```

Question 54

``` Shock of blood loss 30-40% HR, BP, Cap refill, UO ml/hr, Mental state ```

Answer 54

``` HR >120, BP low, Cap refill >2sec, UO ml/hr 10-20, Mental state confused ```

Question 55

``` Shock of blood loss >40% HR, BP, Cap refill, UO ml/hr, Mental state ```

Answer 55

``` HR >140, BP low, Cap refill >2sec, UO ml/hr anuric, mental state lethargic ```