An rScO₂-guided bundled physiologic management strategy and postoperative delirium in elderly hip arthroplasty: a proof-of-concept randomized controlled trial

Postoperative delirium (POD) is a prevalent and severe complication after hip arthroplasty in the elderly. Its pathogenesis is multifactorial, involving inflammatory, metabolic, and hemodynamic pathways. Regional cerebral oxygen saturation (rScO₂) monitoring via near-infrared spectroscopy can detect cerebral hypoxia, a potentially modifiable contributor. This randomized controlled trial assessed whether an rScO₂-guided bundled physiologic management strategy was associated with a lower incidence of POD in this high-risk population. In this randomized controlled trial, 176 patients scheduled for hip arthroplasty were randomly assigned to an intervention group ( n = 88) or a control group ( n = 88). In the intervention group, a structured management protocol was triggered by a decline in rScO₂ (> 10% from baseline), which included systematic optimization of blood pressure, ventilation, oxygenation, temperature, anemia, and cardiac output. In the control group, rScO₂ was monitored but the values were concealed, and anesthesiologists provided standard care. The primary outcome was the incidence of POD within the first three postoperative days, assessed using the 3-Minute Diagnostic Confusion Assessment Method (3D-CAM). A total of 165 patients (82 intervention, 83 control) were included in the per-protocol analysis. The overall POD incidence was 21.2% (35/165). The incidence was significantly lower in the intervention group (13.4%, 11/82) than in the control group (28.9%, 24/83), with a relative risk of 0.46 (95% CI 0.24–0.88, P = 0.015). The intervention group also showed a significantly higher minimum intraoperative rScO₂ (57.7% vs. 56.5%, P = 0.038), greater ephedrine use (52.4% vs. 31.3%, P = 0.006), and less intraoperative hypothermia (8.5% vs. 19.3%, P = 0.046). Extreme-case intention-to-treat sensitivity analyses yielded consistent results. In this single-center trial, an rScO₂-guided bundled physiologic management strategy was associated with a lower incidence of POD in elderly patients undergoing hip arthroplasty. This association may be attributable to the integrated optimization of multiple intraoperative care dimensions rather than improved cerebral oxygenation alone. These findings should be considered preliminary and warrant confirmation in larger multicenter trials. Registered in the Chinese Clinical Trial Registry ChiCTR2400093182 (Date: 29/11/2024).