Shock

Question 1

Define shock

Answer 1

Clinical syndrome caused by inadequate tissue perfusion and oxygenation leading to abnormal metabolic function

Question 2

Name the 4 different types of shock

Answer 2

Cardiogenic
Hypovolaemic
Obstructive
Distributive

Question 3

Give examples of causes of cardiogenic shock

Answer 3

Post-MI - most common
Myocarditis
Dysrhythmia

Question 4

Give examples of causes of hypovolaemic shock

Answer 4

Haemorrhage e.g. trauma, GI bleed, ruptured AAA

Fluid loss e.g. burns, dehydration, pancreatitis

Question 5

Give examples of causes of obstructive shock

Answer 5

Cardiac tamponade
Tension pneumothorax
PE

Question 6

Give examples of causes of distributive shock

Answer 6

Sepsis
Anaphylaxis
Neurogenic shock - spinal cord injury, traumatic brain injury

Question 7

What clinical features often define shock?

Answer 7

Systolic BP < 90 mmHg
MAP < 65 mmHg

AND

Evidence of tissue hypoperfusion

• Mottled skin
• Urine output <0.5ml/kg/h
• Lactate > 2mmol/L

Question 8

How do you calculate MAP?

Answer 8

MAP = CO x SVR
therefore, shock can result from inadequate cardiac output or a loss of systemic vascular resistance or both

OR

MAP = (systolic + 2xdiastolic)/3

Question 9

How do you calculate cardiac output?

Answer 9

CO = stroke volume x HR

Question 10

Which types of shock cause inadequate cardiac output?

Answer 10

Hypovolaemic shock
Cardiogenic shock
Obstructive shock

Question 11

Which types of shock cause peripheral circulatory failure i.e. loss of systemic vascular resistance?

Answer 11

Distributive shock

• Sepsis
• Anaphylaxis
• Neurogenic shock

Dissociative shock

• carbon monoxide poisoning
• cyanide poisoning

Question 12

What happens in sepsis caused by gram negatives?

Answer 12

Gram negatives produce endotoxin

This causes sudden and severe shock without signs of infection

Question 13

Which type of shock causes a decreased HR?

Answer 13

Neurogenic shock

Question 14

What is the pathophysiology behind anaphylactic shock?

Answer 14

A type 1 IgE-mediated hypersensitivity reaction leading to histamine release

Question 15

What is an anaphylactoid reaction?

Answer 15

Direct (i.e. not immune-mediated) release of mediators from mast cells

Usually in response to a drug

Question 16

What are the signs and symptoms of anaphylaxis?

Answer 16

Respiratory
- Lower airway: dyspnoea, wheeze, chest
tightness, bronchospasm
- Upper airway obstruction (swelling of lips,
tongue, pharynx, epiglottis), laryngeal oedema - stridor
- Type 2 respiratory failure

Skin

• Itchy, urticarial rash
• Angioedema

CVS

• Oedema
• Tachycardia, hypotension

GI

• D&V
• Abdominal cramps

Question 17

What are some differential diagnoses of anaphylaxis?

Answer 17

Carcinoid crisis from carcinoid tumour
Phaeochromocytoma
Systemic mastocytosis
Hereditary angioedema

Question 18

What is the management of anaphylaxis?

Answer 18

1. Airway
   - Secure airway
   - If serious upper airway oedema call anaesthetist
   - 15L O2 via NRBM
2. Call for help, lie patient flat, raise patient’s legs
3. Give IM adrenaline 0.5mL of 1:1000 - repeat every 5 min if no response
4. Breathing
   - If wheeze, give salbutamol 5mg NEB B2B
5. Circulation
   - IV 0.9% sodium chloride
   - IV chlorphenamine 10mg
   - IV hydrocortisone 200mg
   - Monitor ECG
6. Admit to ward/ICU and observe for 4-6hr after symptoms have stopped

Question 19

What investigation helps you to differentiate hypovolaemic shock from cardiogenic shock?

Answer 19

Echocardiogram

Question 20

How do you manage haemorrhagic shock?

Answer 20

Stop bleeding if possible
2L IV 0.9% sodium chloride
Crossmatch blood and request O Rh negative blood in emergency
Give FFP with red cells
Consider IV tranexamic acid 2g

Question 21

What is SIRS?

Answer 21

Systemic Inflammatory Response Syndrome

Defined as 2 or more of:

• Temp >38 or <36
• HR >90
• RR >20 or PaO2 <4.3
• WCC >12 or <4

Question 22

Define sepsis (in relation to SIRS), severe sepsis and septic shock

Answer 22

Sepsis = SIRS + source of infection
Severe sepsis = sepsis + organ disorder
Septic shock = sepsis + hypotension despite adequate fluid resuscitation

Question 23

What is the management of sepsis?

Answer 23

BUFALO

Blood cultures (before starting Abx) & bloods (FBC, U&Es, glucose, clotting, LFTs)
Urine output
Fluids - 500ml IV 0.9% sodium chloride over 15 min
Antibiotics - IV broad spectrum stat
Lactate - ABG/VBG
Oxygen - 15L NRBM

Question 24

What should you consider giving to a septic patient that is non-responsive to fluids?

Answer 24

Systemic vasopressor e.g. noradrenaline or phenylephrine