Increased plasma concentration of adrenomedullin during and after major surgery

Adrenomedullin (AM), a novel vasodilatory peptide, appears to participate in the regulation of circulation. Recent studies have reported a relationship between AM and cytokine. The present study was performed to determine whether major surgery, which is accompanied by an altered cytokine production, affects the concentration of plasma AM. Eighteen patients undergoing major upper abdominal and thoracoabdominal surgery were thus studied. Arterial blood samples were obtained before anesthetic induction (PRE), 2h after a surgical incision was made (2H), at the end of surgery (END), at postoperative day 1 (1POD), and at 3POD. The concentrations of plasma AM and serum interleukin (IL)-6 were measured. The levels of plasma AM were found to be significantly higher at END (P < 0.001), 1POD (P < 0.0001), and 3POD (P < 0.05) compared with PRE. A significant correlation was found between the concentrations of serum IL-6 and plasma AM (r = 0.59, n = 18, P < 0.01). These results suggest that major surgical stress might thus increase the plasma AM concentration, and such an increase may be related to cytokine induction.