Perioperative cell-mediated immune response.

Innate and acquired immunity play a pivotal role in the host defense response. Pain, surgical stress, tissue injury and invasive micro-organisms are known to modulate complex immune responses in patients undergoing major surgery, which can lead to subsequent increased susceptibility to postoperative infections. Anesthetics may influence the immune response indirectly through modulation of the neurohumoral response or directly by acting on immune competent cells. In particular, cell-mediated immune balance seems to be affected by anesthetics and this might account for anesthetic-dependant risk of postoperative infections. Consequently, in order to fully understand the immunomodulating properties and ensuing clinical relevance of anesthetics it will be necessary to investigate each agent individually and in a variety of clinical settings. The existing research in this field, most of which is experimental, has yielded different results. The goal of further clinical studies must be to establish the immunomodulating properties of individual anesthetic agents so that selection can be tailored to the individual patient's pre-operative immune status and intraoperative course.