Intraoperative hypotension (defined as mean arterial pressure <65 mmHg) is a common occurrence during anesthesia and has been associated with increased risk of intraoperative hypoxia and postoperative complications, including stroke and acute kidney injury. Preventing intraoperative hypotension is therefore critical to reducing postoperative morbidity.

The number of patients undergoing arthroscopic shoulder surgery has been increasing. When performed in the beach chair position, gravitational effects reduce venous return, decrease cardiac output, and predispose patients to hypotension. Anesthetic agents further impair autonomic regulation and vascular tone, exacerbating the risk. Because the brain is positioned above the heart, cerebral perfusion pressure may decrease significantly, increasing the risk of intraoperative ischemia and postoperative neurological complications. Active monitoring and prevention of hypotension are thus essential.

The noninvasive Hypotension Prediction Index (HPI) is a novel, non-invasive tool designed to predict impending hypotensive events and guide timely intervention. While it has been evaluated in some small randomized controlled trials, there is currently a lack of RCTs specifically assessing the use of non-invasive HPI-guided management in patients undergoing arthroscopic shoulder surgery in the beach chair position.

To evaluate whether the use of non-invasive Hypotension Prediction Index-guided management reduces the duration and severity of intraoperative hypotension, as well as the incidence of intraoperative hypoxia and postoperative complications in patients undergoing arthroscopic shoulder surgery in the beach chair position.

The research team will include patients aged 65 to 90 years undergoing arthroscopic shoulder surgery in the beach chair position. Participants will be randomly assigned to either an HPI-guided group or a standard care group without HPI guidance. The duration and severity of intraoperative hypotension have been compared, as well as the incidence of postoperative complications between the two groups. Patients receiving HPI-guided management are expected to experience fewer and shorter episodes of intraoperative hypotension compared to those without HPI guidance.

Inclusion Criteria:

• Non-emergent shoulder arthroscopy performed in the beach chair position, with eligibility criteria including male or female patients aged 65-90 years.

Exclusion Criteria:

• Women who are pregnant, planning to become pregnant during the study period, or breastfeeding
• Individuals with major cardiac diseases, such as severe arrhythmia or heart failure
• Individuals with significant renal disease, e.g., chronic renal failure requiring dialysis
• Individuals with a history of stroke
• Individuals diagnosed with dementia

due to ethical issue

patients and outcome assessor were masking