SCAI Stages of Shock
A - at risk
B - Beginning
C - Circulatory compromise
D - Deteriorating; Damage to organs
E- Extreme
Shock occurs when there is insufficient tissue perfusion. The pathophysiology of shock may be divided into the following aetiological groups:
Septic shock is a major problem and those patients with severe sepsis have a mortality rate in excess of 40%. In those who are admitted to intensive care mortality ranges from 6% with no organ failure to 65% in those with 4 organ failure.
Sepsis is defined as an infection that triggers a particular Systemic Inflammatory Response Syndrome (SIRS). This is characterised by body temperature outside 36°C - 38°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. Those with organ failure have severe sepsis and those with refractory hypotension -septic shock.
During the septic process there is marked activation of the immune system with extensive cytokine release. This may be coupled with or triggered by systemic circulation of bacterial toxins. These all cause endothelial cell damage and neutrophil adhesion. The overall hallmarks are thus those of excessive inflammation, coagulation and fibrinolytic suppression.
The surviving sepsis campaign (2012) highlights the following key areas for attention: