PORTAL ENDOTOXIN AND CYTOKINE RESPONSES DURING ABDOMINAL AORTIC-SURGERY

Interleukin-6 (IL-6) is a major marker of tissue injury. Surgery induc es a systemic IL-6 response related to the magnitude of the operation. An exaggerated IL-6 response is associated with the development of ma jor complications after aortic aneurysm repair. Endotoxemia is a poten t stimulus for cytokine release and may occur during aortic surgery. T his study attempted to examine whether the observed IL-6 response duri ng abdominal aortic surgery is related to the development of portal en dotoxemia. Serial samples of inferior mesenteric and systemic venous b lood were obtained before, during, and after aortic cross-clamping in eight patients undergoing elective aortic aneurysm surgery. Portal end otoxemia was detected in only five of the eight patients during the su rgery, and there was no correlation with the IL-6 response. Both porta l and systemic IL-6 levels rose during the course of surgery, but, by the time of abdominal wound closure, the mean portal IL-6 levels were eight times higher than the systemic IL-6 levels. These results sugges t that the portal circulation draining the colon is a major source of the previously observed systemic IL-6 response to aortic surgery. The IL-6 response is not clearly related to portal endotoxemia but may ref lect occult cellular injury in the colon occurring during surgery.