Physiology and Pathophysiology of ERAS

In the development and implementation of the enhanced recovery after surgery (ERAS) program, there has been the need to understand the mechanism and the factors that affect the recovery process. Most of the elements considered by the ERAS® Society to have an impact on recovery have a physiological basis, and the interaction between them characterizes the modulation of the stress response. For example, besides surgical incision, some of them such as pain, hemorrhage, immobilization, and quasi starvation have a synergistic effect. The activation of the sympathetic system and the inflammatory response associated with all these surgical elements characterize the surgical stress response, thus leading to a state of low insulin sensitivity, which represents the most important pathogenic factor modulating the perioperative outcome.