Shock is a state in which there is Failure of the circulatory system to maintain adequate cellular perfusion resulting in widespread reduction in delivery of oxygen and other nutrients to tissues. In shock, the mean arterial pressure is less than 60 mmHg or the systolic blood pressure is less than 90 mmHg.
Regardless of the underlying pathology, shock constitutes systemic hypoperfusiondue to reduction either in cardiac output or in the effective circulating blood volume. The end results are hypotension followed by impaired tissue perfusion and cellular hypoxia.
