Gut Microbiota and Pulmonary Complications After Non Cardiac Elective Surgery in Elderly Patients

Inclusion Criteria

• •1. Age: ≥ 65 years old;
• •2. Surgery: Upper abdominal surgery (expected duration ≥ 2 hours);
• •3. Anesthesia methods: general anesthesia, tracheal intubation;
• •4. ASA classification: I-IV levels;
• •5. Postoperative Pulmonary Complications Risk Score (ARISCAT): Medium to High Risk
• •6. Patients or their families are able to understand the research protocol and are willing to participate in this study, providing written informed consent