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

AIM

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%<SpO2≤98% and ORi 0.00. In the control group, FiO2 adjustments were guided solely by SpO2 readings, with ORi values recorded but not used for decision-making. POD was assessed with the Confusion Assessment Method (CAM) and CAM-ICU at multiple time points over 48 hours.

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.

CONCLUSION

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.