The purpose of this study is to develop a high-performance machine learning model combining dynamic baroreflex sensitivity (BRS) metrics and multi-dimensional static clinical features to predict the risk of post-induction hypotension (PIH) in elderly patients undergoing elective non-cardiac surgery under general anesthesia.

Aging significantly alters cardiovascular autonomic function, characterized by elevated sympathetic and decreased parasympathetic tone, rendering elderly patients highly vulnerable to post-induction hypotension (PIH). While existing machine learning models heavily rely on static data (e.g., baseline blood pressure, demographics, medication history), they lack real-time dynamic regulatory inputs, limiting their predictive performance in individualized care.

This single-center, prospective cohort study aims to bridge this gap by introducing preoperative BRS parameters-calculated via the continuous non-invasive arterial pressure (CNAP) method-into machine learning frameworks. A total of 500 patients aged over 65 years scheduled for elective non-cardiac surgery will be enrolled. Preoperative data, including autonomic indices, frailty assessments, and static clinical factors, will be mapped alongside intraoperative events and 30-day postoperative complications. Multiple machine learning algorithms (Logistic Regression, Random Forest, GBDT, XGBoost, LightGBM, and LSTM) will be leveraged and optimized using cross-validation to construct a robust clinical decision-support pipeline.

Inclusion Criteria:

• Aged over 65 years;
• Scheduled for elective non-cardiac surgery;
• American Society of Anesthesiologists (ASA) physical status classification I-III;
• Planned for general anesthesia with endotracheal intubation;
• Patient and legal guardians are capable of understanding the study protocol and willing to provide written informed consent.

Exclusion Criteria:

• Severe peripheral vascular diseases;
• Secondary hypertension;
• Presence of physical tremors (e.g., Parkinson's disease) preventing stable recording;
• Inability to accurately measure upper limb blood pressure;
• Pre-existing cardiac arrhythmias (e.g., atrial fibrillation) that render BRS;
• Psychiatric disorders or cognitive impairments hindering basic cooperation.

Patients scheduled for elective operations