Remimazolam is a novel benzodiazepine with ultra-short onset and offset of its effect. It can
be used for general anesthesia. However, classical benzodiazepine such as midazolam was
reported to increase the risk of postoperative delirium. Thus, the investigators aim to
investigate the effect of remimazolam general anesthesia on postoperative delirium in elderly
patients.