Shock

Question 1

What MAP is considered to represent shock in the context of inadequate organ perfusion?

Answer 1

<60

However, this is a late sign. Any patient presenting with features of shock and signs of organ dysfunction can be in a state of shock even with a MAP >60. Remember the young patient or hypertensive patient for example.

Question 2

What are the 5 main causes of shock?

Answer 2

Hypovolaemia
Cardiac failure
Systemic vasodilatation, e.g. sepsis, anaphylaxis, neurogenic
Obstruction (e.g. PE, tension pneumothorax, tamponade).
Combined causes.

Question 3

Give 6 causes of cardiogenic shock

Answer 3

MI
Thoracic aorta dissection
Cardiac arrhythmias
Acute valvular failure
Drug overdose
Myocarditis

Question 4

Give 4 examples of causes of hypovolaemic shock

Answer 4

Haemorrhage
Fluid losses (diarrhoea, vomiting, polyuria, burns)
Third space fluid loss (pancreatitis)
Adrenal failure

Question 5

Give 5 examples of distributive shock (vasodilation)

Answer 5

Sepsis (caution as patients can also be peripherally vasoconstricted)
Neurogenic autonomic dysregulation
Anaphylaxis
Hepatic failure
Drug overdose
Adrenal failure

Question 6

Give 3 examples of obstructive shock

Answer 6

Pulmonary embolism (life threatening)
Cardiac tamponade
Tension pneumothorax

Question 8

Give 6 causes of hypotension with a raised CVP

Answer 8

Pulmonary embolism
Cardiac tamponade
Right ventricular infarction
Fluid overload in vasodilator shocked patient
Tension pneumothorax
Cardiogenic shock

Question 9

What is the target volume of fluid resuscitation in septic shock?

Answer 9

30ml/kg
2L is standard practice

Question 10

Give 7 dynamic markers of fluid status that can guide fluid resuscitation

Answer 10

HR
BP (MAP rising and aim >60)
Peripheral tissue perfusion
Urine output (>0.5ml/kg/hour)
Venous-arterial CO2 gap </= 0.5mmHg)
Central venous SpO2 >75mmHg
Stroke volume variation <10%

Question 11

6 key management points for shock

Answer 11

ABC, O2 (60–100%); consider intubation if GCS <8.

IV access and fluids: titrate according to BP, CVP, and urine output. (In most cases, it is safe to give 250mL of crystalloid over 5–10min and assess response.)

Inotropes: if there is persistent hypotension in spite of adequate filling.

After initiating inotropes, assess the patient frequently for tachyphylaxis (may require dose titration) and additional haemodynamic insults.

Treat the underlying condition, e.g. infections, cardiac ischaemia, or arrhythmia.

Talk to the relatives. Discuss the resuscitation status.

Question 12

Inotropic support options (4)

Answer 12

Noradrenaline
Metaraminol
Dobutamine
Levosimendan

Question 14

Define sepsis

Answer 14

Infection with systemic inflammatory response

Question 15

Define severe sepsis

Answer 15

Sepsis with organ dysfunction

Question 16

Define septic shock

Answer 16

Sepsis with hypotension (or lactate >4) refractory to fluid resuscitation

Question 17

What is the mortality associated with a lactic acidosis?

Answer 17

Patients presenting with a lactate of >5mmol/L and a pH <7.35 have a mortality of >50%.

Question 18

What are the two types of lactic acidosis?

Answer 18

Type A (hypoxia caused by tissue hypoperfusion)
Septic shock (tissue hypoperfusion)
Shock
Severe anaemia
Severe hypoxia
Catecholamine excess (e.g. phaeochromocytoma or exogenous)
Severe exercise

Type B (non-hypoxic/abnormal metabolism)
Sepsis (mitochondrial impairment)
Renal failure
Hepatic failure
Uncontrolled diabetes mellitus
Malignancy (leukaemia, lymphoma)
Acute pancreatitis
Thiamine deficiency
Drug induced: Paracetamol overdose, metformin, methanol, ethanol, salicylates, ethylene glycol, salbutamol and cyanide.
Rare causes: Hereditary enzyme defects such as glucose-6-phosphatase and fructose-1,6-diphosphatase deficiency