Postoperative Delirium in Elderly Patients Undergoing Major Spinal Surgery: Role of Cerebral Oximetry

Background: Perioperative cerebral hypoperfusion/ischemia is a major inciting factor of postoperative delirium, which is coupled with adverse outcome in elderly patients. Cerebral oximetry enables noninvasive assessment of the regional cerebral oxygen saturation (rSO₂). This study aimed to investigate whether perioperative rSO ₂ variations were linked to delirium in elderly patients after spinal surgery. Materials and Methods: Postoperative delirium was assessed for 48 hours postsurgery in 109 patients aged over 60 years without a prior history of cerebrovascular or psychiatric diseases by the Confusion Assessment Method for the intensive care unit and the intensive care delirium screening checklist. The rSO₂ values immediately before and throughout surgery were acquired. The preoperative cognitive functions, patient characteristics, and perioperative data were recorded. Results: During the 48-h postoperative period, 9 patients (8%) exhibited delirium. The patients with delirium showed similar perioperative rSO₂ values as those without, in terms of the median lowest rSO ₂ values (55% vs. 56%; P=0.876) and incidence (22%, both) and duration of decline of rSO ₂<80% of the baseline values. The serially assessed hemodynamic variables, hematocrit levels, and blood gas analysis variables were also similar between the groups, except for the number of hypotensive events per patient, which was higher in the patients with delirium than in those without (4, interquartile range [IQR] 3 to 6 vs. 2, IQR: 1to 3; P=0.014). Conclusions: The degree and duration of decrease of the perioperative rSO 2 measurements were not associated with delirium in elderly patients after spinal surgery.