4 collapsed patients. Shock Shock is a profound haemodynamic and metabolic disturbance characterised...

4 collapsed patients

Shock

Shock is a profound haemodynamic and metabolic disturbance characterised by failure of the circulatory system to maintain adequate perfusion to vital organs.

4 Main types of shock

• Septicaemic• Cardiogenic• Anaphylactic• Hypovolaemic

Clinical features

Features of end-organ under-perfusion e.g.

– Pallor– cold peripheries– oliguria (urine output <

30ml/hour)– faints,

confusion/agitation

• skin colour - pallor, cyanosis, jaundice

• pulse rate and volume - carotid pulse

• blood pressure • heart and chest sounds • Signs of blood loss• Cerebral hypoperfusion

Case 1

• A teenager aged 18 is found at home• Febrile and appears confused and is irritable

Examination

• Temperature 39.7• P 120• BP 90/50• Noted to have a faint

rash on skin

Questions

• Which illnesses you consider?• What actions need to be undertaken• How quickly should any intervention be

made?• What are the potential risks ?• Should any action be undertaken relating to

friends or family?

Neiserria meningitidis

Meningococcal septicaemia

The typical presentations are: • meningitis • sepsis with rash • sepsis without rash • bacteraemia without sepsis

(uncommon) • Any of the first three

presentations are common, and sepsis without rash in particular is difficult to diagnose clinically.

Key manifestations of meningococcal infection include:

• abrupt onset • very rapid progression • haemorrhagic rash,

which may be petechial only

Septicaemic shock

• Complicates 20% of cases of septicaemia. It is a state of profound tissue hypoperfusion with the following features:

• evidence of infection • fever or hypothermia • hypotension • tachypnoea • mental confusion• It classically occurs following infection by Gram negative

organisms, though in fact shock may also occur due to Gram positive infection as well as fungal infection.

Pathogeneisis

• Exposure to endotoxin• Lipopolysacchride component of bacterial cell wall• Triggers Monocytes, cytokine release, neutrophils and

inflammatory mediators• Factor XII release promotes coagulation• Tissue damage• Capillary leakage• Vasodilatation• Intravascular coagulation• Tissue damage and organ failure

Treatment

• Reverse tissue hypoxaemia• Circulatory support and monitoring• Monitor urine output• Treat underlying infection

Meningococcus• Gram negative• Different types A,B C • B and C commonest in UK• Group B main cause of life

threatening septicaemia/meningitis

• Vaccine covers A and C not B – who is vaccinated?

• Carriage rate

Treatment and prophylaxis

• IV Benzyl penicillin• Cefotaxime if allergic

Prophylaxis• RifampacinTreatment• Swabs• Notifiable

Case 2

• A 62 year old man is found at home• He is collapsed • He is confused but rousable• He is pale and noted to be sweating

Examination

• BP 60 • Unable to palpate wrist pulse• P 40 • HS audible

Questions

• What are the possible causes of this picture?• What actions would you take when this man

arrives in A/E?• What tests are available?• Which organs might be particularly at risk?• Actions?

Cardiogenic shock

• Extreme form of cardiac failure.

• Characteristic features:

• poor tissue perfusion: – poor cerebral function – cool extremeties – oliguria

• hypotension• poor cardiac output• Cardiogenic shock is most

commonly caused by myocardial infarction.

• Mortality approaches 90%.

Management

• 100% O2• Analgesia• Aspirin• Thrombolysis• PTCA/Stent• Correct bradycardia • Inotropic support• Monitor urine output

Case 3

• A 22 year old student is our with friends for a curry

• He suddenly collapses• He is noted to be pale and cold

Examination

• BP 70/50• P 100• Raised rash on trunk and legs• Swelling of lips• Audible wheeze

Questions

• What is the likely cause of this collapse?• What are the possible precipitants of the

condition?• Why has this mans BP dropped?• What actions need to be taken?

AetiologyMost commonly encountered precipitants include food, drugs and venom

– vaccines – drugs:

• antibiotics • heparin • neuromuscular blocking agents • iron injections • anti-inflammatory analgesics • contrast media

– hyposensitising agents – insect bites and stings- wasp, bee – blood products – certain foods, for example peanuts,

almonds,walnut, fish,milk

Relative significance of these factors varies with the age -

– food is particularly significant in children

– drugs being a much more common cause in the elderly.

• it is more likely to occur after parenteral injections. The reaction is likely to be more severe if the patient is re-exposed.

• although atopic patients are more susceptible, why some individuals should react so markedly to this repeat exposure to an antigen is not understood.

Case 4

• A jockey is thrown from his horse on the racecourse at Newmarket

• When the doctor arrives he is responding to pain

• His radial pulse cannot be felt

Examination

• Noisy respiration• Responding to pain• P 120 carotid but not

palpable at wrist• Sweating

Questions

• What will kill this man first?• What does the doctor need to do first ?• What is the AVPU score?• What is the most likely reason for the

tachycardia and the low BP?• Where in the body might he be loosing blood

and how much?• What actions are required?

Hypovolaemic shock – early symptoms

• Tachycardia (catecholamine release) • Skin pallor (vasoconstriction) • Hypotension (hypovolaemia) • Confusion, aggression, drowsiness, and coma

(cerebral hypoxia and acidosis) • General weakness (hypovolaemia) • Thirst (hypovolaemia) • Reduced urine output (reduced perfusion)

Hypovolaemic shock• Hypovolaemia is assessed using

urine output, pulse rate, blood pressure and capillary return.

• These may be used to determine the grade of shock.

• Capillary return is said to be decreased if the blanching of skin produced by pressure at an extremity remains longer than 2 seconds, or the time to say "capillary return".

• A drop in blood pressure, i.e. grade III, is a late sign in shock and is often preterminal.

• Causes• Blood loss overt• Blood loss concealed• Dehydration ( DKA,

Vomiting and diarrhoea)

Grade 1 15% blood volume (~750 ml) Mild resting tachycardia Grade 2 15 - 30% blood volume (750 - 1500 ml) Moderate tachycardia, fall in pulse pressure, delayed capillary return Grade 3 30 - 40% blood volume (1500 - 2000 ml) Hypotension, tachycardia, low urine output Grade 4 40-50% blood volume (2000 -2500 ml) As above but with profound hypotension

Grades of hypovolaemic shock

Always think of the spleen

Peripheral oxygen saturations Pulse Respiratory rate Urine output Base deficit/lactate (from arterial blood) Temperature Mental state Pulse pressure Central venous pressure Arterial pressure

Signs to watch during fluid replacement

Questions