Population Pharmacokinetics and Pharmacodynamics of Ciprofol

The goal of this observational study is to learn how the anesthetic drug ciprofol works in older adults who are having limb surgery under general anesthesia at Shanghai Geriatric Medical Center. The study will help researchers build a population model to better understand how the drug moves through the body (PK) and how it affects patients (PD). This model may help doctors use a Target-Controlled Infusion (TCI) system to adjust the drug dose more precisely. The main question it aims to answer is: Does ciprofol work safely and effectively in older adults during orthopedic surgery? Participants already receiving ciprofol as part of their regular anesthesia care will: 1. Provide blood samples at different time points during and after surgery. 2. Have their vital signs and anesthesia-related data recorded before, during, and after surgery. 3. Be monitored for side effects and recovery indicators such as the Aldrete score and signs of postoperative delirium. Researchers will use this information to: 1. Build and test a population PK/PD model for ciprofol. 2. Simulate recommended TCI dosing plans. 3. Explore how individual responses to ciprofol relate to recovery and safety outcomes. This study may help improve anesthesia care for elder adults by making drug dosing safer and more effective.