Protocol for a cohort study: evaluating the effect of neoadjuvant immunochemotherapy on intraoperative remifentanil consumption during IoC2-guided anesthesia in elderly patients with esophageal cancer

BACKGROUND: The influence of neoadjuvant immunochemotherapy (nICT) on intraoperative opioid consumption during esophagectomy for cancer is not well understood. IoC2 enables real-time antinociceptive depth monitoring. This study assesses nICT's effect on remifentanil requirements in elderly patients using IoC2. METHODS: = 30). All patients will receive a standardized anesthetic protocol. The primary outcome is the mean intraoperative remifentanil infusion rate (μg/kg/min). Secondary outcomes include: total intraoperative dose of sufentanil; postoperative cumulative opioid consumption at PACU, 12, 24, 48, and 72 h; pain scores, PCIA attempts, and rescue analgesia use at PACU, 12, 24, 48, and 72 h post-surgery, and the incidence of moderate-to-severe pain (NRS ≥ 4) at these time points; as well as delirium, postoperative complications, chest tube removal time, and hospital length of stay. DISCUSSION: This study aims to clarify the effect of neoadjuvant therapy on opioid requirements during esophageal cancer surgery. By employing precise IoC2 monitoring, we aim to establish a methodological basis for developing individualized, precise anesthesia-analgesia strategies and to provide prospective evidence for their clinical application. TRIAL REGISTRATION: The study protocol is registered with the Chinese Clinical Trial Registry under registration number ChiCTR2500105958, dated July 15, 2025.