The history and evolution of circulatory shock.

This article reviews the development of early ideas regarding the origins and pathogenesis of shock. The early history of shock is related primarily to traumatic shock. More recent history centers on differentiation of clinical syndromes and individual characteristics. Definitions, classification systems, pathogenic theories, and treatments have evolved. Progress has been aided by constant development of improved assessment technologies. Today, shock is not a single syndrome and the definition of shock no longer is descriptive in nature. The most accepted current definition involves an oxygen supply/demand imbalance that can have various causes-hypovolemia, cardiac dysfunction, vascular failure, or obstructive processes.