Heart Rate Variability Changes and Postoperative Delirium After Major Abdominal Surgery

N/ANot Yet RecruitingNCT07783464

The First Affiliated Hospital with Nanjing Medical University500 enrolled

Overview

This prospective observational cohort study aims to investigate whether early postoperative changes in heart rate variability (HRV) relative to baseline are associated with the development of postoperative delirium (POD) in older patients undergoing elective major abdominal surgery under general anesthesia. Patients aged 65-85 years will be enrolled. Resting HRV will be measured at 10:00 AM on the day of surgery before anesthesia induction and at the same time point on the first postoperative day using a validated heart rate monitoring device. HRV parameters will be derived from standardized 5-minute recordings. Changes in HRV parameters from baseline will be calculated, and their associations with POD occurrence will be evaluated. Postoperative delirium will be assessed daily from 24 hours after surgery to postoperative day 7, using the 3-Minute Diagnostic Interview for Confusion Assessment Method (3D-CAM). The study will also explore the potential utility of HRV-derived markers for early POD risk stratification. Approximately 500 participants will be enrolled.

Postoperative delirium (POD) is a common neurocognitive complication following major surgery in older adults and is associated with increased morbidity, prolonged hospitalization, and adverse clinical outcomes. However, objective and easily obtainable biomarkers for early identification of patients at high risk of POD remain limited. Heart rate variability (HRV) reflects autonomic nervous system regulation and may provide a non-invasive marker of physiological stress and impaired autonomic adaptability. Major abdominal surgery induces substantial systemic stress responses, including inflammation, neuroendocrine activation, and autonomic disturbances. Whether early postoperative alterations in HRV are associated with subsequent POD development remains unclear. This is a single-center, prospective observational cohort study. Patients aged 65-85 years undergoing elective major abdominal surgery under general anesthesia will be consecutively enrolled. Baseline demographic characteristics, comorbidities, frailty status, cognitive function, and perioperative clinical variables will be collected. Resting HRV will be measured at 10:00 AM on the day of surgery before anesthesia induction and again at the same time point on the first postoperative day using a validated heart rate monitoring device. HRV analysis will be performed based on standardized 5-minute recordings in accordance with established recommendations for short-term HRV assessment. Time-domain, frequency-domain, and nonlinear HRV parameters will be calculated. Postoperative delirium will be assessed daily from 24 hours after surgery to postoperative day 7 using the 3-Minute Diagnostic Interview for Confusion Assessment Method (3D-CAM). Additional clinical outcomes include delirium severity, delirium duration, postoperative cognitive function, quality of recovery, postoperative nausea and vomiting, and length of hospital stay. The primary objective is to evaluate the association between early postoperative HRV changes and the occurrence of POD after adjustment for clinically relevant confounding factors, including age, baseline cognitive function, frailty status, surgical duration, and baseline HRV. Secondary analyses will explore the relationship between representative HRV markers and postoperative clinical outcomes and assess their potential utility for early POD risk stratification.

Eligibility

Sex: ALLMin age: 65 YearsMax age: 85 Years

Medical Language ↔ Plain English

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.

Outcomes

Primary Outcomes

Occurrence of postoperative delirium within 7 days after surgery

Postoperative delirium will be assessed daily from postoperative day 1 to postoperative day 7 using the Chinese version of the 3-Minute Diagnostic Interview for CAM-defined Delirium (3D-CAM). Delirium diagnosis will be based on the Confusion Assessment Method (CAM) algorithm.

Time frame: Postoperative day 1 to postoperative day 7 after surgery

Secondary Outcomes

Severity of postoperative delirium

The severity of postoperative delirium will be assessed using the Delirium Rating Scale-Revised-98 (DRS-R-98) among patients who develop postoperative delirium. The DRS-R-98 scores range from 0 to 46, with higher scores indicating greater delirium severity (worse outcome).

Time frame: Postoperative day 1 to postoperative day 7 after surgery

Duration of postoperative delirium

The duration of postoperative delirium episodes will be recorded from the first diagnosis of delirium until resolution during the postoperative assessment period.

Time frame: Postoperative day 1 to postoperative day 7 after surgery

Change in cognitive function after surgery

Cognitive function will be assessed using the Montreal Cognitive Assessment (MoCA). Scores range from 0 to 30, with higher scores indicating better cognitive function (better outcome).

Time frame: Postoperative day 7

Quality of recovery after surgery

Quality of recovery will be assessed using the 15-item Quality of Recovery Questionnaire (QoR-15). Scores range from 0 to 150, with higher scores indicating better quality of recovery (better outcome).

Time frame: Postoperative day 7

Heart Rate Variability Changes and Postoperative Delirium After Major Abdominal Surgery

Overview

Conditions

Interventions

Eligibility

Locations (1)

Outcomes

Primary Outcomes

Secondary Outcomes

Central Contacts