Heart Rate Variability Changes and Delirium After Major Abdominal Surgery

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This is a single-center, prospective observational study enrolling adults aged 65–85 undergoing elective major abdominal surgery under general anesthesia. Resting HRV will be measured before anesthesia and on postoperative day 1 using 5-minute recordings, with analysis across time-domain and frequency-domain metrics. Postoperative delirium will be tracked daily from 24 hours after surgery through day 7 using the 3D-CAM. Researchers will explore whether changes in HRV from baseline are associated with POD and consider HRV-derived markers as potential early indicators. The study aims to improve understanding of autonomic biomarkers for POD risk in elderly surgical patients.

Why it matters

Who can join: the full rules

Inclusion Criteria

1. Patients admitted to Jiangsu Provincial People's Hospital who are scheduled to undergo elective major abdominal surgery under general anesthesia.
2. Older patients aged 65 to 85 years.
3. Expected postoperative hospital stay of ≥7 days.
4. Body mass index (BMI) between 18.5 and 28.0 kg/m².
5. American Society of Anesthesiologists (ASA) physical status classification I-III.
6. Patients who are conscious, mentally competent, and able to cooperate with heart rate variability (HRV) measurements, questionnaire assessments, and follow-up evaluations.
7. Patients who voluntarily participate in the study and provide written informed consent.

Exclusion Criteria

1. Patients with ASA physical status classification ≥IV or patients with end-stage cancer.
2. Patients with implanted cardiac pacemakers, implantable cardioverter-defibrillators, or other electronic devices that may interfere with ECG signal acquisition.
3. Patients with severe or unstable cardiovascular diseases, including but not limited to acute coronary syndrome, symptomatic bradycardia, sick sinus syndrome, second-degree or higher atrioventricular block, atrial fibrillation, atrial flutter, frequent premature beats, or other arrhythmias that may affect heart rate variability analysis.
4. Patients with diseases affecting autonomic nervous system function, including confirmed primary or secondary autonomic dysfunction, such as Parkinson's disease, multiple system atrophy, severe diabetic autonomic neuropathy, severe peripheral neuropathy, poorly controlled hyperthyroidism or hypothyroidism, and systemic amyloidosis.
5. Patients with a history of organic central nervous system diseases or psychiatric disorders, including major traumatic brain injury, stroke (ischemic or hemorrhagic), intracranial mass lesions, epilepsy, schizophrenia, bipolar disorder, major depressive disorder, or other severe psychiatric disorders.
6. Patients with severe baseline cognitive impairment or inability to complete cognitive assessments, including any of the following: (1) preoperative baseline Montreal Cognitive Assessment (MoCA) score \<14 points; (2) previously diagnosed dementia, preoperative delirium, coma, or other severe disturbances of consciousness; or (3) inability to complete standardized cognitive assessments due to severe visual impairment, hearing impairment, language barriers, or other causes.
7. Patients unable to undergo HRV measurement within 24 hours after surgery, including those with severe perioperative complications, emergency reoperation, extremely unstable vital signs, or requiring continuous deep sedation after surgery.
8. Patients who have taken anticholinergic medications, beta-blockers, antiarrhythmic drugs, or other medications that may significantly affect autonomic function within 1 month before study enrollment.
9. Patients who are currently participating in any other clinical trial.

Where it's running

• The First Affiliated Hospital with Nanjing Medical University
  Nanjing, Jiangsu, China Recruiting

Study contacts

• Study coordinator: Junbei Wu
• Email: wujunbei88@sina.cn
• Phone: +86 13813955365

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How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.