Maintenance Anesthetics and Postoperative Delirium in Older Adults Undergoing General Anesthesia: A Systematic Review and Network Meta-analysis of Randomized Trials

IntroductionPostoperative delirium (POD) is a frequent and serious complication in older surgical patients. The optimal maintenance anesthetic to prevent POD remains uncertain due to fragmented and inconsistent evidence. This systematic review and network meta-analysis will compare the effectiveness of remimazolam, propofol, sevoflurane, desflurane, isoflurane, xenon, and ciprofol, and establish an evidence-based ranking to guide clinical practice. Methods and AnalysisWe will systematically search CENTRAL, Embase, MEDLINE, Web of Science, and major trial registries without language or date restrictions. Two reviewers will independently screen studies, extract data, and assess risk of bias with the ROBUST-RCT tool. Random-effects network meta-analyses will estimate pooled risk ratio (RR) for dichotomous outcomes and mean difference (MD) or standardized mean difference (SMD) for continuous outcomes. Treatments will be ranked using the surface under the cumulative ranking curve (SUCRA). Certainty of evidence will be appraised with the Confidence in Network Meta-Analysis (CINeMA) framework. Ethics and disseminationEthical approval is not required as only published data will be analyzed. Results will be submitted to a peer-reviewed journal. The protocol was registered in PROSPERO (CRD420251118351; submitted 11 August 2025).