High Cerebral Oxygen Saturation Levels During One-Lung Ventilation Predict Better Cognitive and Clinical Outcomes After Thoracic Surgery: A Retrospective Observational Study

Background: Cerebral desaturation during one-lung ventilation (OLV) in thoracic surgery has been associated with postoperative cognitive dysfunction (POCD). While the adverse effects of low intraoperative regional cerebral oxygen saturation (rScO2) are well documented, the potential clinical value of maintaining supranormal rScO2 levels has not been thoroughly studied. Methods: We conducted a retrospective observational study based on a previously collected cohort from a tertiary university hospital. Adult patients undergoing elective thoracic surgery between January 2019 and December 2022 were included, provided they received lidocaine either intravenously or via a paravertebral block as part of a standardized anesthetic protocol. Patients were divided into the following two groups based on their mean INVOS values 30 min into OLV: those with rScO2 ≥75% (H-INVOS group) and <75% (L-INVOS group). Intraoperative physiological variables, inflammatory biomarkers, cognitive function via the Mini-Mental State Examination, and postoperative outcomes were analyzed. Results: The H-INVOS group exhibited significantly higher preoperative lung function, higher PaO2 and PaCO2 values during OLV, and higher hemoglobin concentrations across all timepoints. They also demonstrated better preservation of cognitive function, lower IL-18 expression at 24 h postoperatively, and shorter hospital stays. There were no statistically significant differences in intraoperative hemodynamics or ventilatory mechanics.