Physiologic Response to Traumatic Shock

Traumatic injury results in major physiologic alterations that begin at the time of injury and persist until recovery is complete. The response of the body is divided into two phases — the acute phase and the flow phase. The acute phase is characterized by shock with changes in hormone concentration. These hormones, either alone or in combination, result in lipolysis, amino acid release, gluconeogenesis, and glycolysis. The flow phase of injury is a catabolic process that is characterized by an increased protein metabolism. Hypermetabolism and increased nitrogen losses are seen. The magnitude of these alterations is directly related to the severity of injury. Tissues with the highest oxygen consumption are more susceptible to injury and death. Cellular function does not depend on oxygen alone but also on the ability of the cells to use available oxygen. If the body is unable to compensate through biochemical, hormonal, and metabolic activities, an irreversible state results unless appropriate interventions are instituted promptly