Shock

Question 1

Define shock

Answer 1

Term to describe acute circulatory failure with inadequate or inappropriately distributed tissue perfusion, resulting in generalised hypoxia and/or an inability of the cells to utilise oxygen

Question 2

What is meant by ‘inadequate or inappropriately distributed tissue perfusion’

Answer 2

Inadequate substrate (glucose and oxygen) for aerobic cellular respiration

Question 3

How would you recognise shock

Answer 3

Skin is pale, cold, sweaty and vaso-constricted
Pulse is weak and rapid
Pulse pressure is reduced (not arterial as this is maintained until large blood loss)
Reduced urine output
Confusion, weakness, collapse, coma

Question 4

Is venous or mean arterial pressure (MAP) a better indicator of shock

Answer 4

Venous

Pulse pressure reduced from shock but MAP may be maintained (only decreases if v large amount of blood loss)

Question 5

Effects of shock

Answer 5

Prolonged hypotension which can lead to life threatening organ failure after recovery from the acute event (possibly linked with inflammatory response)
Long capillary refill time (CRT)

Question 6

Describe Capillary Refill Time as a measure of Shock

Answer 6

If takes >3 seconds to turn pink after 5 seconds of compression = early/accurate sign of shock

Question 7

Types of shock

Answer 7

Hypovolaemic shock
Cardiogenic shock
Distributive shock (3 types)

Haemorrhagic shock
Heat exposure (heat exhaustion)

Unsure:
Anaemic shock
Cytotoxic shock

Question 8

What are 3 types of distributive shock

Answer 8

Septic shock
Anaphylactic shock
Neurogenic shock

Question 9

Cause of hypovolaemic shock

Answer 9

Low blood volume, as a result of loss of blood or loss of fluid
Can be secondary to haemorrhagic shock

Question 10

Hypovolaemic shock: What can cause loss of blood?

Answer 10

Acute GI bleeding
Trauma
Peri-post-operative
Splenic rupture

Question 11

Hypovolaemic shock: What can cause loss of fluid?

Answer 11

Dehydration - diarrhoea and vomitting
Burns - heat damage increase capillary permeability so plasma leaks
Pancreatitis

Question 12

Causes of cardiogenic shock

Answer 12

Heart doesn’t pump due to:

• Cardiac tamponade - blood in pericardial sack placing pressure on heart thereby limiting cardiac output
• Pulmonary embolism - flow of blood to lungs is blocked
• Acute MI
• Fluid overload
• Myocarditis - inflammation of the muscle itself

Question 13

Why does cardiac tamponade prevent heart from pumping

Answer 13

Blood in pericardial sack places pressure on heart thereby limiting cardiac output

Question 14

When do you get sepsis

Answer 14

When a systemic inflammatory response is associated with an infection

Question 15

When do you get septic shock

Answer 15

When sepsis is complicated by persistent hypotension that is unresponsive to fluid resuscitation

Question 16

What causes anaphylactic shock

Answer 16

• Release of IgE due to allergic response
• Massive release of histamine and other vasoactive mediators causing haemodynamic collapse
• Accompanied by breathlessness and wheeze (due to bronchospasm)

Question 17

What are the different groups of Haemorrhagic Shock classification

Answer 17

(Tennis score)

Class I, II and III

Question 18

Haemorrhagic Shock classification: Describe class I

Answer 18

15% blood loss
Pulse <100bpm
BP normal
Resp rate 14-20
Urine output greater than 30ml/hr
Slightly anxious

Question 19

Haemorrhagic Shock classification: Describe class II

Answer 19

15-30% blood loss
Pulse >100bpm
BP normal (due to ANS/ increased sympathetic activity)
Pulse pressure decreased
Resp rate 20-30
Urine output 20-30ml/hr
Mental status: mildly anxious

Question 20

Haemorrhagic Shock classification: What is earliest sign of class II

Answer 20

Tachycardia

Question 21

Haemorrhagic Shock classification: Describe class III

Answer 21

30-40% blood loss
Pulse >120bpm
BP decreased
Pulse pressure decreased
Resp rate 30-40
Urine output 5-15ml/hr
Mental status: confused

Question 22

What haemorrhagic shock class would someone be is had a resp rate of 21, decreased pulse pressure but normal BP

Answer 22

Class II

therefore blood loss around 15-30%

Question 23

What haemorrhagic shock class would someone be is had a urine output of 15ml/hr and pulse of 125bpm

Answer 23

Class III

therefore blood loss around 30-40%

Question 24

What signs would show someone to have 15% blood loss

Answer 24

Class I Haemorrhagic shock
Pulse <100bpm
BP normal
Resp rate 14-20
Urine output greater than 30ml/hr
Slightly anxious

Question 25

How does blood loss lead to release of adrenaline

Answer 25

- Reduction in ventricular filling - Fall in BP and SV - Results in hypotension - Reduced stimulation of baroreceptors in aortic arch and carotid sinuses - Increased sympathetic activity with release of noradrenaline and adrenaline

Question 26

What is effect of adrenaline and nor-adrenaline on vascular system

Answer 26

Vasoconstriction | Increased myocardial contractility and heart rate, helps restore BP and CO

Question 27

What is autotransfusion

Answer 27

Reduced capillary BP leads to greater level of net movement of fluid into the vascular compartment from the tissues

Question 28

What hormones counter hypotension

Answer 28

``` ADH/Vasopressin Angiotensin II Aldosterone Cortisol Glucagon ```

Question 29

How does ADH/Vasopressin counter hypotension

Answer 29

Vasopressin is released in response to decreased Blood Volume which which binds to V2 receptor resulting in insertion of Aquaporin 2 into the lumen of the collecting duct, resulting in increased water reabsorption

Question 30

How does RAAS counter hypotension

Answer 30

Reduction in the perfusion of renal cortex stimulates Juxtaglomerular appartus to release RENIN. Renin converts Angiotensinogen (from liver) to Angiotensin I. Angiotensin I is converted to Angiotensin II by ACE (in lungs). Angiotensin II causes thirst, is a potent vasoconstrictor and stimulates secretion of Aldosterone by the adrenal cortex. Both cause Na+ and therefore water retention - to help restore circulating volume and blood pressure.

Question 31

How does Cortisol counter hypotension

Answer 31

Increases fluid retention

Question 32

How does Glucagon counter hypotension

Answer 32

Raises blood sugar levels | Fluid also moves into blood then due to osmotic effect

Question 33

Clinical presentation of hypovolaemic shock

Answer 33

Inadequate tissue perfusion Increased sympathetic tone Tachycardia - narrow pulse pressure and weak pulse Sweating BP may be maintained initially but later hypotension Bradycardia

Question 34

Describe how you would differentially diagnose inadequate tissue perfusion (for someone with hypovolaemic shock) - Not capillary test

Answer 34

``` Skin = cold, pale, clammy, slate-grey Brain = drowsiness and confusion ```

Question 35

Clinical presentation of cardiogenic shock

Answer 35

Signs of myocardial failure Raised jugular venous pressure (JVP) Gallop rhythm Basal crackles and pulmonary oedema

Question 36

Clinical presentation of septic shock

Answer 36

Pyrexia and rigors Nausea and vomiting Vasodilation with warm peripheries Bounding pulse

Question 37

Clinical presentation of anaphylactic shock

Answer 37

``` Signs of profound vasodilation Warm peripheries Low BP Tachycardia Bronchospasm Pulmonary oedema ```

Question 38

What organs are most at risk of shock

Answer 38

Kidneys Lungs Heart Brain

Question 39

What could result from shock affecting kidneys

Answer 39

Acute tubular necrosis

Question 40

What could result from shock affecting the lungs

Answer 40

Acute Respiratory Distress Syndrome (ARDS)

Question 41

What could result from shock affecting the heart

Answer 41

Myocardial ischaemia and infarction

Question 42

What could result from shock affecting the brain

Answer 42

confusion irritability coma

Question 43

Treatment of shock

Answer 43

ABC | Airway Breathing Circulation

Question 44

Treatment of shock - B (of ABC)

Answer 44

``` Breathing Give 100% O2 Correct any immediately life threatening problems such as: Congestive HF Bronchospasm Tension pneumothorax ```

Question 45

Treatment of shock - C (of ABC)

Answer 45

Circulation Establish secure IV access Give fluid quickly and blood if acute blood loss Ensure haemostasis i.e. stop bleeding

Question 46

What is acute respiratory distress syndrome

Answer 46

Type of resp failure characterised by rapid onset of widespread inflammation in the lungs

Question 47

Which of these is true in ARDS: High Pulmonary Arterial pressure (PAOP) No cardiac failure

Answer 47

No cardiac failure is true Pulmonary Arterial Pressure is NORMAL

Question 48

Extrapulmonary causes of ARDS

Answer 48

Shock of any cause Head injury Drug reaction Sepsis

Question 49

Pulmonary causes of ARDS

Answer 49

Pneumonia Chemical pneumonitis Smoke inhalation Near drowning

Question 50

Pathophysiology of ARDS

Answer 50

Injury to alveolar capillary membrane results in leakage of fluid into alveolar spaces There is resulting neutrophil invasion which attracts more neutrophils (exudative phase) Eventually fibroblasts come in and initiate healing (proliferative phase) Forms Scar tissue (fibrotic phase) Results in severely stuff lungs and thus Severe difficultly in ventilation and thus O2 blood perfusion

Question 51

*Clinical presentation of ARDS

Answer 51

Cyanosis Tachypnoea (quick breathing) Tachycardia Peripheral vasodilation

Question 52

Investigations and management of sepsis

Answer 52

``` BUFALO Blood cultures Urine output (measure) iv Fluid (administer) Administer broad spectrum Antibiotics serum Lactate (measure) administer high flow Oxygen ```

Question 53

What is septic shock

Answer 53

Life-threatening condition that is characterised by low blood pressure despite adequate fluid replacement, and organ dysfunction or failure

Question 54

Symptoms of septic shock

Answer 54

``` feeling dizzy or faint a change in mental state – such as confusion or disorientation diarrhoea nausea and vomiting slurred speech severe muscle pain severe breathlessness less urine production than normal – for example, not urinating for a day cold, clammy and pale or mottled skin loss of consciousness ```

Question 55

Define neurogenic shock

Answer 55

Distributive type of shock resulting in low blood pressure, occasionally with a slowed heart rate, that is attributed to the disruption of the autonomic pathways within the spinal cord. It can occur after damage to the central nervous system, such as spinal cord injury and traumatic brain injury.

Question 56

Management of Hypovolaemic shock

Answer 56

pg.790 (also do management of other shocks)