A state with significant reduction in systemic tissue perfusion, resulting in decreased delivery of oxygen and reduced removal of waste products, leading to tissue injury.


Blood pressure = cardiac output x peripheral resistance


Cardiac output is dependent on venous return


Cardiac output = heart rate x stroke volume


Clinical forms of shock


Hypovolaemic shock





Third spacing


Cardiogenic shock

Myocardial infarction

Valve dysfunction



Cardiac failure


Obstructive shock

Obstruction within veins

Compression of heart

Pressure on vessels


Distributive forms of shock


Septic shock

Uncomplicated sepsis

Severe sepsis

Septic shock


Allergic shock



Neurogenic shock

Sympathetic decrease

Parasympathetic increase

Spinal shock

Vasovagal syncope




Patient assessment

Airway and C spine control

Breathing and ventilation - aim for 95% O2 sats

Circulation and haemorrhage control

Disability – neurological examination

Exposure – complete examination



Recognise if shock is present

Early features;


Cutaneous vasoconstriction


Any injured patient who is cool and tachycardic is considered to be in shock until proved otherwise.


Haemodynamic collapse

Inadequate perfusion of;





Respiratory rate

Narrowed pulse pressure


Identify the cause of the shock state

Patient history

Treat simultaneously


After trauma

Hamorrhagic or nonhaemorrhagic


General management principles

The Golden Hour

Establish and maintain a clear airway

Ensure adequate ventilation

Oxygen to keep sats above 95%

Adequate intravenous access

Continuous cardiac monitoring

Urinary catheter

Recording of fluid balance

Central venous monitoring

Physiologically desirable position

Maintain optimum temperature

Blood gases

Acid / base balance assessment

Psychological and family support.

Observation of response to treatment

Inotropes and vasoconstricting drugs

Treatment of underlying disorder


Specific management measures


Hypovolaemic shock

Arrest bleeding

Intravenous fluids

Assess response

Oral rehydration

Treat underlying causes


Diarrhoea and Vomiting in Children

Continue breast feeding

Encourage fluid intake

No fizzy drinks or fruit juice

Oral Rehydration Salts

Consider nasogastric ORS

IVIs for shock or deterioration

Eg. 0.9% saline or saline with 5% glucose

Check Na, K, urea, creatinine, glucose

After rehydration give normal food and milk


Cardiogenic shock

Early thrombolysis

Valve replacement surgery

Correct dysrhythmias





Obstructive shock




Chest decompression

Chest drainage


Septic shock

Initial resuscitation



Correct cause


Inotropic therapy


Allergic shock










Neurogenic shock

Spinal shock

Vasovagal syncope




Treat cause



Stages of shock


Compensated shock


Neurological compensations

Endocrine compensations

Increased absorption of fluids


Blood pressure maintained

Circulatory system protected


Progressive shock


Condition deteriorates

Blood pressure starts to fall

Hypoperfusion of;




medulla oblongata

Last window of opportunity for curative treatment


Irreversible shock

Still alive, but die

Transient increase in BP

Treat shock before this stage


The Golden Hour 

Treatment ASAP, or within one improves survival

Stop the bleeding, treat injuries and restore blood pressure within one hour

The ‘Golden Hour’ begins at the time of trauma


Physiological response


Neurological response

When a baroreceptor is stretched it is stimulated and produces nerve impulses

Sensory nerves travel from the baroreceptors to the medulla oblongata

Here they influence the activity of the vasomotor and cardiac centres

Impulses from the baroreceptors inhibit the sympathetic outflow from these centres

When blood pressure falls there is a reduced firing rate from the baroreceptors

Reduced inhibitory effect on the sympathetic outflow

This results in increased sympathetic outflow from the medulla

There will also be inhibition of the parasympathetic vagal outflow


Endocrine response


Renin - Angiotensin - Angiotensinogen - Aldosterone

Antidiuretic Hormone, Vasopressin


Clinical features of classical shock

Arterial vasoconstriction

Venous vasoconstriction

Pallor / cyanosis

Cold and clammy





Oliguria / anuria 

Jugular venous pressure


Lactic acidosis

Coronary and cerebral circulation

End organ damage

Vascular damage


In cardiogenic shock

Pulmonary oedema


In distributive shock

Initially warm / red peripheries


























Special groups


Shock and athletes

Athletes have increased blood volume, cardiac output, stroke volume but reduced pulse rate

Are brilliant compensators


Shock and the elderly

Unable to increase heart rate and efficiency of myocardial contraction

Atherosclerosis means even slight reductions in tissue perfusion may lead to early end organ injury

Reduce pulmonary compliance results in early hypoxic injury

Kidneys are less able to preserve blood volume

Kidneys sensitive to reduced blood flow

Therefore mortality and morbidity increases with age

Therefore give aggressive resuscitation and monitor carefully

Young adults are much better compensators than older adults


Shock and children

Child blood volume 80ml / Kg

Excellent compensators

Systolic BP maintained until 30% of blood volume is lost


Look out for;

Poor skin perfusion


Progressive weakening of peripheral pulses

Skin mottling (as opposed to clammy)

Cool extremities

Prolonged capillary refill

Anxious, irritable, confused

Reduced organ perfusion and oliguira are late signs


No progressive development of hypotension

Sudden decompensation

Past 30 % blood loss BP and CO fall rapidly

Bradycardia may replace tachycardia

Give early crystalloid fluid resuscitation

Get early assessment by a surgeon


Management in children

In suspected shock give 20ml / Kg warmed isotonic crystalloid

3 for 1 rule applies

Repeated 2 more times to a total of 60ml / Kg

Consider PRBCs at 10ml / Kg


Peripheral vein

Central line

Intraosseous, anterior tibial bone marrow


Urine output and specific gravity is a good titration aid for fluid resuscitation


Hypothermia may render the child refractory to treatment
















Screening, any 2 of the following


Fever > 38oC or <36oC

Heart rate >90

Tachypnoea >20

Leucocytosis >12,000 or <4,000

Altered mental status

Hyperglycaemia >6.6 mmol / L (unless diabetic)





>10% immature forms

Increased C-reactive protein

SBP < 90 mmHg

Oedema or positive fluid balance




Any history of,




Abdominal pain, diarrhoea, distension


Cellulitis, septic arthritis, fasciitis, wound infection


Catheter infection




Severe sepsis care pathway – sepsis 6


Oxygen, high flow rate, aim for >94%

Blood culture, before antibiotics, also cultures

IV antibiotics

Fluid resuscitation, if hypotensive give 20ml/Kg bolus

Serum lactate, grey top bottle on ice

Catheterise, hourly fluid balance































What are the 3 stages of shock

Give 4 possible causes of hypovolaemia

Describe the surface area of the body in the rule of 9

Give 4 causes of cardiogenic shock

Give 3 causes of obstructive shock


What receptors detect blood pressure in the carotid sinus

What part of the brain contains the vasomotor centre

What is the initial dose of adrenalin used in anaphylaxis

List 5 places where blood may be lost

List 5 possible clinical features of septic shock


Which statement is true of the Golden Hour

It begins at the time of the trauma

It begins when the patient arrives in A and E