Shock Pathophysiology: Classifications and Management

Abstract

Shock is a pathological state in which there is an insufficiency in oxygen supply and demand. Ultimately, it results in global hypoperfusion and a resulting increase in anaerobic respiration causing lactic acidosis. Maintaining adequate oxygen delivery in the critical care setting is of primary importance in the management of a critically ill patient. When oxygen supply is inadequate, the body undergoes several physiological changes to maintain the oxygen delivery requirements and perfusion pressure. This stage is referred to as compensated shock, and early signs of shock may be appreciated during this stage. When compensatory mechanisms are inadequate and DO2 begins to fall beyond the critical point, shock has progressed to the uncompensated stage. During this stage, there is rapid deterioration of the patient due to prolonged hypoxia and anaerobic respiration. Multiple Organ Dysfunction Syndrome (MODS) is the development of potentially reversible physiological derangement involving two or more organ systems not involved in the causative disorder, which results in persisting states of shock, sepsis and hypoperfusion and a major cause of high mortality in the intensive care unit reaching a range of 11–54% in septic pediatric patients. The final stage of shock is irreversible shock, which is also referred to as refractory shock. This final stage of shock carries a 96–99% mortality rate.