Initiators and propagators of the metabolic response to injury.

Injury produces tissue hypoperfusion and subsequent reperfusion, afferent neural activity, and immune and vascular endothelial activation. These, in turn, set up a cascade of events coordinated by the central nervous system and at the level of individual tissues such as the liver, gut, and skeletal muscle. They are mediated by a complex array of neutrophil and macrophage products. The changes result in hypermetabolism, lypolysis, lysis of skeletal muscle and visceral protein, and expanded extracellular fluid with consequent organ failure.