Effect of Opioid-free Anaesthesia on Postoperative Delirium in Elderly Patients Undergoing Gastrointestinal Surgery

Effect of Opioid-free Anaesthesia on Postoperative Delirium in Elderly Patients Undergoing Gastrointestinal Surgery: a Single-centre, Prospective, Randomized Controlled Trial

Background Postoperative delirium (POD) is a common acute and transient form of brain dysfunction in elderly patients following surgery that can lead to serious adverse clinical outcomes and even death. Although existing studies have preliminarily investigated the effects of opioid-free anaesthesia (OFA) on POD, high-quality evidence on these effects for elderly patients undergoing gastrointestinal surgery remains limited. This study aims to investigate the effects of OFA on the development of POD in elderly patients following gastrointestinal surgery.

Methods and analysis:

This single-centre, prospective, randomized controlled trial will be conducted at the First Affiliated Hospital of Shandong First Medical University, China. A total of 406 patients aged 65 years or older who are scheduled for elective gastrointestinal surgery will be randomly allocated to receive either opioid-free anaesthesia (OFA; dexmedetomidine, esmolol, and esketamine) or conventional opioid-based anaesthesia (OBA). The primary outcome is the incidence of POD 7 days after surgery. The secondary outcomes are all-cause mortality within 30 days after surgery, intraoperative haemodynamic changes, the 15-item quality of recovery (QoR-15) scores at 24 h, 48 h, and 72 h after surgery, complications during postoperative hospitalization, pain numerical rating scale (NRS) score at 72 h after surgery, incidence of nausea and vomiting at 72 h after surgery, morphine milligram equivalent for analgesics at 72 h after surgery, duration of anaesthesia (from induction to discontinuation), duration of surgery (from skin incision to the last suture), duration of post-anaesthesia care unit (PACU) stay, and length of hospital stay.

Discussion:

The results of this study may shed light on the effects of OFA on POD in elderly patients undergoing gastrointestinal surgery. The study is designed on the basis of the following key hypothesis: the use of opioid drugs for anaesthesia may increase the risk of POD through mechanisms such as blood-brain barrier destruction, neuroinflammatory responses, and central nervous system depression. Through the single-centre and prospective design of this randomized controlled trial, this study will directly analyse differences in the effects of OFA and conventional OBA on the incidence of POD, haemodynamic stability and long-term cognitive function in elderly patients.

gastrointestinal surgery.

Inclusion Criteria:

1. Age ≥ 65 years
2. American Society of Anesthesiologists (ASA) physical status classification I-III
3. Scheduled for elective gastrointestinal surgery under general anaesthesia
4. Body mass index (BMI) between 18.0 and 30.0 kg/m²

Exclusion Criteria:

1. Refusal to undergo surgery
2. Emergency surgery
3. Language impairment or severe hearing or visual deficits that hinder effective communication with research or surgical staff
4. History of neurological or psychiatric disorders, including Alzheimer's disease (AD), other forms of dementia, stroke, or psychosis
5. Long-term use of psychotropic medications (e.g., clozapine, risperidone, olanzapine, haloperidol, chlorpromazine)
6. Cardiac or craniocerebral surgery within the past year
7. Participation in other interventional clinical studies within the past 3 months
8. Preoperative cognitive impairment defined as a modified Telephone Interview for Cognitive Status (TICS-M) score ≤ 27
9. Patients will only be enrolled once, even if a subsequent surgery related to the primary procedure is performed