Shock

Question 1

Shock

Septic, Haemorrhagic,Neurogenic, Cardiogenic, Anaphylactic

Septic Shock (1)

Answer 1

Sepsis is defined as an infection that triggers a particular Systemic Inflammatory Response Syndrome (SIRS).

• This is characterised by body temperature outside 36 oC - 38 o C,
• HR >90 beats/min,
• respiratory rate >20/min,
• WBC count >12,000/mm3 or < 4,000/mm3.

Patients with infections and two or more elements of SIRS meet the diagnostic criteria for sepsis

Question 2

Shock

Septic, Haemorrhagic,Neurogenic, Cardiogenic, Anaphylactic

Septic Shock (2)

Answer 2

• extensive cytokine release.
• excessive inflammation, coagulation and fibrinolytic suppression.

The surviving sepsis campaign (2012) highlights the following key areas for attention:

• Prompt administration of antibiotics to cover all likely pathogens​
• Haemodynamic stabilisation. Many patients are hypovolaemic and require aggressive fluid administration. Aim for CVP 8-12 cm H2O, MAP >65mmHg.
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Question 3

Shock

Septic, Haemorrhagic,Neurogenic, Cardiogenic, Anaphylactic

Haemorrhagic shock (1)

Answer 3

• The average adult blood volume comprises 7% of body weight. Thus in the 70 Kg adult this will equate to 5 litres. This changes in children (8-9% body weight) and is slightly lower in the elderly.

Question 4

Shock

Septic, Haemorrhagic,Neurogenic, Cardiogenic, Anaphylactic

Haemorrhagic shock (2)

Answer 4

In patients suffering from trauma, the most likely cause of shock is haemorrhage. However, the following may also be the cause or occur concomitantly:

• Tension pneumothorax
• Spinal cord injury
• Myocardial contusion
• Cardiac tamponade

When assessing trauma patients it is worth remembering that in order to generate a palpable femoral pulse an arterial pressure of >65mmHg is required.

Once bleeding is controlled and circulating volume normalised the levels of transfusion should be to maintain a Hb of 7-8 in those with no risk factors for tissue hypoxia and Hb 10 for those who have such risk factors.

Question 5

Shock

Septic, Haemorrhagic,Neurogenic, Cardiogenic, Anaphylactic

Neurogenic Shock

Answer 5

• occurs most often following a spinal cord transection, usually at a high level.
• The result is either decreased sympathetic tone or increased parasympathetic tone
• the effect of which is a decrease in peripheral vascular resistance mediated by marked vasodilation.
• results in decreased preload and thus decreased cardiac output. There is decreased peripheral tissue perfusion and shock is thus produced. In contrast with many other types of shock peripheral vasoconstrictors are used to return vascular tone to normal.
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Question 6

Shock

Septic, Haemorrhagic,Neurogenic, Cardiogenic, Anaphylactic

Cardiogenic Shock

Answer 6

• main cause is ischaemic heart disease.
• In the traumatic setting, direct myocardial trauma or contusion is more likely
• Treatment is largely supportive and transthoracic echocardiography should be used to determine evidence of pericardial fluid or direct myocardial injury
• If injury is of a blunt nature and is associated with cardiogenic shock the right side of the heart is the most likely site of injury with chamber and or valve rupture.
• patients require surgery to repair these defects

Question 7

Shock

Septic, Haemorrhagic,Neurogenic, Cardiogenic, Anaphylactic

Anaphylactic Shock

Answer 7

Severe, life-threatening, generalised or systemic hypersensitivity reaction:

• Adrenaline is by far the most important drug in anaphylaxis and should be given as soon as possible.
• Adrenaline can be repeated every 5 minutes if necessary. The best site for IM injection is the anterolateral aspect of the middle third of the thigh.