[The neuroendocrine and metabolic response to surgical stress]

Surgical stress and post-operative pain evoke complex neuroendocrine and tissue responses aiming at defence from injury and recovery of body integrity. Such a reaction appears to be a real "hormonal storm" which is mainly induced by Sympathetic Nervous System and sympatho-adrenomedullary and hypothalamic-pituitary-adrenal systems activation and, in the periphery, by the release of inflammatory mediators at the site of injury. These substances by means of complex regulatory mechanisms and reciprocal interactions induce significant cardiovascular, metabolic, inflammatory and immunologic changes. However, this response may became excessive and contribute to an increase in postoperative morbidity and mortality. Since pain is a major factor in neuroendocrine response triggered by surgical injury every effort must be made to achieve effective intra and post-operative pain control.