Summary of review: Shock is a clinical syndrome characterised by hypotension (i.e. a systolic blood
pressure less than 90 mmHg or a mean arterial pressure less than 60 mmHg or reduced by greater than
30%, for at least 30 minutes), oliguria (i.e. a urine output less than 20 mL/hr or 0.3 ml/kg/hr for 2
consecutive hours), and poor peripheral perfusion (e.g. cool and clammy skin which demonstrates poor
capillary refill). Hypovolaemic and cardiogenic shock are associated with disorders that cause an underlying
haemodynamic defect of a low intravascular volume and a reduction in myocardial contractility,
respectively.