Intelligent thermoregulation strategy versus routine thermal management on myocardial injury after noncardiac surgery during gastrointestinal tumor resection in elderly patients (SAGE): a multicenter, parallel-group, superiority trial

Background: Inadvertent perioperative hypothermia is associated with adverse cardiovascular outcomes, but adequately powered trials using high-sensitivity troponin endpoints is lacking. The SAGE trial evaluates whether an intelligent, closed-loop thermoregulation strategy reduces myocardial injury after noncardiac surgery (MINS) in high-risk elderly patients. Methods: This prospective, multicenter, parallel-group, randomized controlled superiority trial conducted at seven tertiary hospitals in China. Participants aged ≥65 years scheduled for elective gastrointestinal tumor resection under general anesthesia are randomly assigned (1:1) to intelligent closed-loop warming (target 36.8 °C, upper limit 37.0 °C) or routine thermal management (active warming only if core temperature ≤35.5 °C). The primary outcome is the incidence of MINS within the first 2 postoperative days, adjudicated using high-sensitivity troponin thresholds per AHA criteria. Secondary outcomes include surgical site infection, transfusion requirement, hypothermia burden, emergence delirium, delayed emergence, and postoperative shivering. With 695 participants per group (total 1,390, accounting for 10% dropout), the trial has 80% power at a one-sided significance level of 0.05 to detect a 6 absolute percentage point reduction in MINS (12% to 6%) with a superiority margin of −2 percentage points. Discussion: The SAGE trial is designed to generate new evidence on the relationship between intraoperative hypothermia exposure and postoperative cardiovascular complications. It will evaluate whether closed-loop targeted normothermia reduces myocardial injury and will explore hypothermia exposure thresholds that may inform individualized perioperative management for geriatric surgical patients. Trial Acronym: Intelligent Thermoregulation Strategy for Advanced-Age Elders undergoing gastrointestinal tumor resection (SAGE). Trial Registration: Chinese Clinical Trial Registry (ChiCTR), identifier: ChiCTR2600117264. Registered on January 21, 2026 (http://www.chictr.org.cn).