Study Summary: The Effect of a Simple Arm Cuff Procedure on Lung Complications After Surgery in Older Adults 1. What is the purpose of this study? This clinical study aims to find out if a simple, non-invasive procedure called Delayed Remote Ischemic Preconditioning (RIPC) can help reduce lung complications (like pneumonia or breathing difficulties) in older patients (aged 65 and above) after non-cardiac and non-chest surgery. 2. What is the RIPC procedure? RIPC involves briefly and repeatedly applying and releasing pressure on one upper arm using a standard blood pressure cuff. This is done 24 hours before surgery. The goal is to gently stimulate the arm's circulation, which may activate the body's natural protective mechanisms and help protect the lungs during and after surgery. RIPC Group: The cuff will inflate to a higher pressure (200 mmHg) for 5 minutes, then release for 5 minutes. This cycle repeats 4 times. Control Group: The cuff will inflate to a very low pressure (20 mmHg) with the same timing, serving as a comparison to see if the higher pressure has a specific effect. 3. Who can participate? Patients may be eligible if they: Are 65 years of age or older. Are scheduled for elective non-cardiac, non-chest surgery under general anesthesia, expected to last 1-3 hours. Are in relatively stable health (ASA physical status I-II). Patients cannot participate if they have certain pre-existing conditions, such as significant heart or lung disease, severe infections, or bleeding disorders. 4. What will happen during the study? Before Surgery: Eligible patients will receive a full explanation and sign a consent form. They will be randomly assigned (like flipping a coin) to either the RIPC group or the Control group. The procedure will be performed 24 hours before surgery. Some blood tests and an ultrasound scan will be done. During Surgery: Standard anesthesia and surgical care will be provided. After Surgery: We will monitor patients for any lung complications within 7 days after surgery. Additional blood tests and ultrasound scans will be performed to check lung function and look for signs of inflammation. We will also follow up 90 days after surgery to check on their overall recovery. 5. What are the potential benefits and risks? Potential Benefit: Participants may have a lower risk of developing postoperative lung complications. The knowledge gained may help future patients. Potential Risks: The arm cuff procedure may cause temporary discomfort, numbness, or minor bruising. There is a very small risk of more serious injury to the arm. The study team is trained to minimize these risks and will monitor patients closely. All standard risks associated with surgery and anesthesia still apply. 6. How is patient safety ensured? This study has been carefully reviewed and approved by an Ethics Committee to ensure it is scientifically sound and ethically conducted. Participation is voluntary, and patients can withdraw at any time without affecting their standard medical care. All personal information will be kept confidential. The study is sponsored and led by the Shanghai Geriatric Medical Center. Study Version: V3.0 (September 2, 2025) Contact: For further questions, please contact the research team at the participating hospital.