The goal of this clinical trial is to assess the viability of dexmedetomidine hydrochloride nasal spray under minimal or no supervision and to further investigate novel clinical applications for this medication. This study aims to investigate the following aspects: the incidence of adverse respiratory and circulatory events requiring medical intervention following the administration of dexmedetomidine nasal spray for pre-anesthetic sedation, its sedative efficacy and onset time, and its impact on the quality of post-anesthesia recovery and the occurrence of postoperative delirium. Researchers will compare dexmedetomidine hydrochloride nasal spray to a placebo (a look-alike substance that contains no drug) to see the incidence and severity of adverse events following administration. Participants will receive either dexmedetomidine nasal spray or a placebo 45 minutes before anesthesia induction. The blinded assessor will continuously monitor and record vital signs, adverse events, and the level of sedation. More importantly, observations and records should be made for respiratory and circulatory events that require medical intervention. A follow-up assessment will be conducted within three days after the operation to evaluate the incidence of postoperative delirium and patient satisfaction.