Postoperative Interleukin-6 and Cortisol Concentrations in Elderly Patients with Postoperative Confusion

Abstract

Objective: To investigate changes in plasma interleukin (IL)-6, cortisol or noradrenaline concentrations after surgery in elderly patients with postoperative confusion. Methods: We studied 80 patients aged 70–90 years undergoing abdominal surgery and measured plasma IL-6, cortisol or noradrenaline concentrations before surgery, at the end of surgery, and 24 and 48 h after surgery. Results: Plasma IL-6 concentrations in elderly patients with postoperative confusion were 83.2 ± 30.5, 49.3 ± 14.1 and 42.9 ± 19.4 pg·ml^–1 at the end of surgery, and 24 and 48 h after surgery, respectively, being significantly higher than in elderly patients without postoperative confusion (58.0 ± 37.5, 36.1 ± 20.0 and 28.2 ± 16.7 pg· ml^–1). Plasma cortisol concentrations in elderly patients with postoperative confusion (42.2 ± 7.8, 38.3 ± 8.3 and 33.1 ± 8.4 µg·dl^–1 at the end of surgery, and 24 and 48 h after surgery, respectively) were significantly higher than in elderly patients without postoperative confusion (32.9 ± 6.7, 30.4 ± 8.6 and 25.6 ± 6.5 µg·dl^–1, respectively). There were no significant differences in plasma norepinephrine concentrations at all sampling points between elderly patients with and without postoperative confusion. However, plasma IL-6 and cortisol concentrations were related in elderly patients with postoperative confusion (at the end of surgery and 24 and 48 h after surgery). However, there was no relationship between plasma IL-6 and cortisol concentrations 24 and 48 h after surgery in elderly patients without postoperative confusion. Conclusion: Elderly patients with postoperative confusion had increased plasma IL-6 and cortisol concentrations. The interaction between IL-6 and cortisol after surgery is associated with developing postoperative confusion in the elderly patients.