The sudden life-threatening condition resulting from severe injury and characterized by progressive impairment of all physiological systems of the body. The main characteristic of shock is the failure of capillary circulation in the tissues owing to impairment of cardiac output and overcontraction of arteries and veins, capillary dysfunction, and changes in the rheological properties of blood. Thus blood pressure and respiration decrease, dangerously enfeebling and quickening the pulse. < Shock can be brought on by an injury, burns, surgery, incompatible blood transfusion, anaphylaxis, functional cardiac disorders, loss of blood to tissues and organs and excessive loss of blood.
Shock, used in a different sense, is applied to those persons in an unusual mental state or persons with severe emotional disturbances, mental shock and emotional shock.
The condition of physical shock was described by the French surgeon H. F. Ledran in 1737 and by the Russian physician N. I. Pirogov in 1870.