Manipulation of the Metabolic Response in Clinical Practice

Surgical injury is followed by profound changes in endocrine metabolic function and various host defense mechanisms leading to catabolism, immunosuppression, ileus, impaired pulmonary function, and hypoxemia. These physiologic changes are supposed to be involved in the pathogenesis of postoperative morbidity. Effective afferent neural blockade with continuous epidural local anesthetic techniques inhibits a major part of the endocrine metabolic response, leading to improved protein economy but without important effects on inflammatory or immunologic responses. In contrast, pain treatment with other modalities such as nonsteroidal antiinflammatory drugs (NSAIDs) and opioids has only a small inhibitory effect on endocrine metabolic responses. Preoperative high-dose glucocorticoid therapy provides additional pain relief and improves pulmonary function, but it reduces the inflammatory response (acute-phase proteins, cytokines, hyperthermia) and immune function. Minimally invasive surgery leaves the endocrine metabolic responses largely unaltered but reduces the inflammatory response and immune suppression. Thus several techniques are available to modify the stress responses in elective surgery patients. The effect of these techniques to alter endocrine metabolic and inflammatory responses during severe surgical illness has not been established. Neural blockade and minimally invasive surgery have improved outcome following elective surgery, especially when integrated into a multimodal postoperative rehabilitation program. Application of this knowledge from pathophysiologic responses to uncomplicated surgical injury should be explored in patients with severe surgical illness.