Goal of studyOur aim was to examine whether cerebral frontal cortex O2 desaturation may be related with the development of delirium symptoms’ after cardiac surgery in the elderly during the intensive care unit (ICU) staying.Materials and methodsA prospective, before and after, longitudinal study in II-IV ASA class patients scheduled for cardiac surgery and undergoing intravenous general anesthesia with remifentanil plus propofol was done. Clinical and surgical parameters, cardiopulmonary function, intraoperative cerebral oxygen saturation (rSO2) and bispectral index were continuously recorded and corrected throughout the surgery. Severity of delirium was represented as a score of the Intensive Care Delirium Screening Checklist (ICDSC) during the patients’ stay in the ICU under the assumption that higher ICDSC score indicated severe delirium.Results and discussionPatients, n = 44, 77.3% male, aged 59.9 ± 1.9 years old, scheduled to coronary (36.4%), aortic valve replacement (18.2%), mitral valve replacement (13.6%), coronary plus valve replacement (13.6%) and others (18.2%) surgery, on pump 98.4% were enrolled. A reduction of the rSO2 higher than 10% at the end of the surgery compared with basal values was detected in a 46.5% of the patients. Reduction of rSO2 higher than 10% at the end of the surgery was related with significantly higher values of delirium symptoms’ development during the intensive care unit post-surgery staying (rSO2 higher ≥ 10% 68.8 vs. rSO2 higher < 10% 31.3%, P < 0.05).ConclusionDelirium symptoms’ development during the intensive care unit post-surgery staying is related with reduced intraoperative cerebral oxygen saturation in the elderly subjected to cardiac surgery.Disclosure of interestThe authors have not supplied their declaration of competing interest.