title: High serum cortisol level is associated with increased risk of delirium after coronary artery bypass graft surgery: a prospective cohort study.
abstract: BACKGROUND
  The pathophysiology of postoperative delirium remains poorly understood. The purpose of this study was to examine the relationship between serum cortisol level and occurrence of early postoperative delirium in patients undergoing coronary artery bypass graft (CABG) surgery.
  
  
  METHODS
  A total of 243 patients undergoing elective CABG surgery were enrolled. Patients were examined twice daily during the first five postoperative days and postoperative delirium was diagnosed by using the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU). Blood samples were obtained between 7 a.m. and 8 a.m. on the first postoperative day and serum cortisol concentrations were then measured. Multivariate logistic regression analyses were performed to identify risk factors of postoperative delirium.
  
  
  RESULTS
  Postoperative delirium occurred in 50.6% (123 of 243) of patients. High serum cortisol level was significantly associated with increased risk of postoperative delirium (OR 3.091, 95% CI 1.763-5.418, P < 0.001). Other independent risk factors of postoperative delirium included increasing age (OR 1.111, 95% CI 1.065-1.159, P < 0.001), history of diabetes mellitus (OR 1.905, 95% CI 1.001-3.622, P = 0.049), prolonged duration of surgery (OR 1.360, 95% CI 1.010-1.831, P = 0.043), and occurrence of complications within the first day after surgery (OR 2.485, 95% CI 1.184-5.214, P = 0.016). Patients who developed postoperative delirium had a higher incidence of postoperative complications and a prolonged duration of postoperative ICU and hospital stay.
  
  
  CONCLUSIONS
  Delirium was a common complication after CABG surgery. High serum cortisol level was associated with increased risk of postoperative delirium. Patients who developed delirium had outcomes worse than those who did not.
authors.affiliation: Department of Anesthesiology and Surgical Intensive Care, Peking University First Hospital, No, 8 Xishiku Street, Beijing 100034, PR China.
authors.forename: Dong-Liang
authors.initials: DL
authors.lastname: Mu
authors.forename: Dong-Xin
authors.initials: DX
authors.lastname: Wang
authors.forename: Li-Huan
authors.initials: LH
authors.lastname: Li
authors.forename: Guo-Jin
authors.initials: GJ
authors.lastname: Shan
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Qin-Jun
authors.initials: QJ
authors.lastname: Yu
authors.forename: Chun-Xia
authors.initials: CX
authors.lastname: Shi
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D001026:Coronary Artery Bypass / Q000009:adverse effects*; D003693:Delirium / Q000097:blood* / Q000209:etiology / Q000523:psychology*; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000097:blood* / Q000523:psychology*; D011446:Prospective Studies; D012307:Risk Factors; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; D006854:Hydrocortisone