Evaluating oxygen reserve index-guided oxygenation for the prevention of postoperative delirium in elderly patients: a randomized controlled trial.

Objective: To assess the effect of oxygen reserve index (ORi)-guided titration of fraction of inspired oxygen (FiO2) on the incidence of postoperative delirium (POD) and the frequency of hyperoxemia episodes, assuming a potential link between hyperoxemia and POD.

Methods: This randomized controlled trial included 114 patients aged 65 years and older, scheduled for elective surgeries lasting over two hours at Health Sciences University Tepecik Training and Research Hospital between October 1, 2023, and July 7, 2024. Patients were randomized into the control group (n=57) or the ORi+pulse oximetry (SpO2) group (n=57). In the ORi+SpO2 group, we dynamically adjusted FiO2 based on the real-time ORi and SpO2 values, targeting 95%

Results: The incidence of POD was significantly higher in the control group than in the ORi+SpO2 group (42.1% vs 12.3%, P<0.001). The average FiO2 levels in the ORi+SpO2 group were significantly lower throughout surgery (P<0.001). The ORi+SpO2 group also exhibited a lower frequency of hyperoxemia episodes.

Conclusions: The ORi-guided oxygenation strategy significantly reduced the incidence of POD in elderly patients by effectively minimizing intraoperative hyperoxemia. Optimizing intraoperative oxygenation through non-invasive monitoring may enhance perioperative outcomes.