Long-term Follow-up of Dexmedetomidine-esketamine and tDCS for Neurocognitive Complications After Surgery

May 7, 2026 updated by: Dong-Xin Wang, Peking University First Hospital

Long-term Follow-up of Perioperative Dexmedetomidine-esketamine Combination and Transcranial Direct Current Stimulation for Prevention of Neurocognitive Complications in Older Patients After Non-cardiac Surgery

Neurocognitive complications, mainly delirium and neurocognitive disorders, are common cerebral complications in older patients after surgery and associated with worse long-term outcomes. An ongoing 2×2 factorial trial conducted by the investigators plan to test the effects of perioperative dexmedetomidine-esketamine combination and transcranial direct current stimulation (tDCS) on postoperative neurocognitive complications in older patients. This long-term follow-up of the ongoing trial aims to investigate the effects of perioperative dexmedetomidine-esketamine combination and tDCS on long-term outcomes in older patients after noncardiac surgery.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Neurocognitive complications, mainly delirium and neurocognitive disorders, are common cerebral complications in older patients after surgery. Occurrence of neurocognitive complications is associated with prolonge hospital stay and increased in-hospital death. Furthermore, occurrence of neurocognitive complications is associated with adverse long-term outcomes, including cognitive decline, poor quality of life, and reduced long-term survival.

Dexmedetomidine is a highly selective alpha 2 adrenergic receptor agonist with sedative, analgesic, and anxiolytic effects. Available evidence showed that perioperative dexmedetomidine decreased early postoperative neurocognitive complications in older patients, possibly by improving analgesia and sleep quality and relieving surgery-related inflammation. However, routine dose dexmedetomidine increases bradycardia and hypotension which are potentially harmful to older patients.

Ketamine is a noncompetitive N-Methyl-D-aspartic acid (NMDA) receptor antagonist and has been used as an anesthetic and analgesic for decades. Esketamine is the S-enantiomer of ketamine and twice as potent as racemic ketamine. Recent studies found that subanesthetic dose of esketamine is effective in improving analgesia and sleep quality and relieving surgery-related stress response. However, even subanesthetic ketamine or esketamine increases neuropsychiatric side effects.

In clinical practice, dexmedetomidine-esketamine combination has been used for premedication in children and postoperative analgesia in adults and showed additive or synergistic effects. An ongoing trial conducted by the investigators plan to test the hypothesis that perioperative use of dexmedetomidine-esketamine combination may prevent postoperative neurocognitive complications in older patients. It is reasonable to hypothesize that perioperative dexmedetomdine-esketamine might also have favorable effects on long-term outcomes.

Transcranial direct current stimulation (tDCS) is a non-invasive neuromodulation technique and increasingly used for treatment of various neurological diseases. Studies in the perioperative settings showed that perioperative use of tDCS improved sleep quality and reduced delirium occurrence early after surgery. The ongoing trial coducted by the investigators plan to test the hypothesis that perioperative use of tDCS may reduce postoperative neurocognitive complications in older patients. Perioperative tDCS might also have favorable effects on long-term outcomes.

This long-term follow-up of the ongoing 2×2 factorial trial aims to investigate the effects of perioperative dexmedetomidine-esketamine combination and tDCS on long-term outcomes in older patients after noncardiac surgery.

Study Type

Interventional

Enrollment (Estimated)

1160

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • China
    • Beijing Municipality
      • Beijing, Beijing Municipality, China, 100034
    • Fujian
      • Fuzhou, Fujian, China, 362011
        • Fujian Medical University Union Hospital
        • Contact:
    • Guangdong
      • Shenzhen, Guangdong, China, 518036
        • Peking University Shenzhen Hospital
        • Contact:
    • Shaanxi
      • Xi'an, Shaanxi, China, 710032
        • Xijing Hospital, Air Force Medical University
        • Contact:
    • Zhejiang
      • Hangzhou, Zhejiang, China, 310006
        • First Affilited Hospital, School of Medicine, Zhejiang University
        • Contact:
      • Hangzhou, Zhejiang, China, 310009
        • Second Affilited Hospital, School of Medicine, Zhejiang University
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Aged 65 to 90 years;
  • Preoperative Mini-Mental State Examination (MMSE) score < 27 points, indicating possible cognitive impairment ranging from mild to moderate;
  • Scheduled to undergo elective non-cardiac, non-neurosurgical surgery under general anesthesia, with an expected surgical duration > 1 hour;
  • Required patient-controlled intravenous analgesia (PCIA) after surgery.

Exclusion Criteria:

  • Preoperative inability to communicate due to coma, severe dementia, endstage disease, or language impairment;
  • History of schizophrenia, epilepsy, Parkinson's disease, brain trauma/surgery, or myasthenia gravis;
  • Presence of metal implants in the intracranial or cervical region (such as cochlear implants, aneurysm clips, deep brain stimulation electrodes), or skin damage or severe skin disease on the head;
  • Severe cardiac dysfunction (left ventricular ejection fraction < 30%), comorbid with sick sinus syndrome, severe bradycardia (heart rate < 50 bpm), or second-degree or higher atrioventricular block, or implantation of a cardiac pacemaker;
  • Uncontrolled hyperthyroidism or pheochromocytoma;
  • Severe liver dysfunction (Child-Pugh class C), severe renal dysfunction (requiring dialysis), or ASA classification ≥ IV;
  • Allergy to dexmedetomidine or esketamine;
  • Participation in other clinical studies within the past 3 months;
  • Other conditions that are deemed unsuitable for study participation.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Factorial Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Dex-Esk + active tDCS
Participants will receive dexmedetomidine-esketamine (Dex-Esk) combination and active transcranial direct current stimulation (tDCS).
Drug: Dex-Esk

Dexmedetomidine-esketamine combination (1 μg/mL dexmedetomidine and 0.5 mg/mL esketamine) will be administered after anesthesia induction, firstly as a loading dose at a rate of [0.4 x body weight (kg)] mL/h for 30 minutes (0.2 μg/kg dexmedetomidine and 0.1 mg/kg esketamine), followed by a maintenance infusion at a rate of [0.1 x body weight (kg)] mL/h (0.1 μg/kg/h dexmedetomidine and 0.05 mg/kg/h esketamine) until one hour before expected end surgery.

Postoperative patient-controlled analgesia will be established with a 100 mL mixture (containing 1.0 μg/mL sufentanil, 1.25 μg/mL dexmedetomidine, and 0.25 mg/mL esketamine in normal saline), programmed to deliver 2-mL boluses with an 8-minute lockout interval and an 1-mL/h background infusion, and provided for 48 hours (at least 24 hours).

Other Names:
  • Dexmedetomidine-esketamine combination
Device: Active tDCS

Active transcranial direct current stimulation (tDCS) will be administered using a battery-powered stimulator. The anode will be positioned over the left dorsolateral prefrontal cortex (DLPFC, F3) and the cathode over the right supraorbital region (Fp2). The stimulation intensity will be set at 2.0 mA, featuring a 30-second linear ramp-up at the beginning and a 30-second ramp-down at the end of each session.

Each participant will receive a total of three 20-minute sessions of active tDCS. The first session will be provided at 40 minutes after extubation in the post-anesthesia care unit. Two other sessions will be provided on postoperative days 1 and 2 (between 10:00 and 12:00 am).

Other Names:
  • Active transcranial direct current stimulation
Experimental: Dex-Esk + sham tDCS
Participants will receive dexmedetomidine-esketamine (Dex-Esk) combination and sham (placebo) transcranial direct current stimulation (tDCS).
Drug: Dex-Esk

Dexmedetomidine-esketamine combination (1 μg/mL dexmedetomidine and 0.5 mg/mL esketamine) will be administered after anesthesia induction, firstly as a loading dose at a rate of [0.4 x body weight (kg)] mL/h for 30 minutes (0.2 μg/kg dexmedetomidine and 0.1 mg/kg esketamine), followed by a maintenance infusion at a rate of [0.1 x body weight (kg)] mL/h (0.1 μg/kg/h dexmedetomidine and 0.05 mg/kg/h esketamine) until one hour before expected end surgery.

Postoperative patient-controlled analgesia will be established with a 100 mL mixture (containing 1.0 μg/mL sufentanil, 1.25 μg/mL dexmedetomidine, and 0.25 mg/mL esketamine in normal saline), programmed to deliver 2-mL boluses with an 8-minute lockout interval and an 1-mL/h background infusion, and provided for 48 hours (at least 24 hours).

Other Names:
  • Dexmedetomidine-esketamine combination
Device: Sham tDCS

Sham transcranial direct current stimulation (tDCS) will be administered using a battery-powered stimulator. The anode will be positioned over the left dorsolateral prefrontal cortex (DLPFC, F3) and the cathode over the right supraorbital region (Fp2). To ensure blinding, the device will deliver a initial 30-second ramp-up to 2.0 mA followed immediately by a 30-second ramp-down to 0 mA. The device remains "ON" for the remaining 19 minutes with no effective current output, mimicking the peripheral scalp sensation without delivering cortical modulation.

Each participant will receive a total of three 20-minute sessions of sham tDCS. The first session will be provided at 40 minutes after extubation in the post-anesthesia care unit. Two other sessions will be provided on postoperative days 1 and 2 (between 10:00 and 12:00 am).

Other Names:
  • Sham transcranial direct current stimulation
Experimental: Placebo + active tDCS
Participants will receive placebo (normal saline) and active transcranial direct current stimulation (tDCS).
Device: Active tDCS

Active transcranial direct current stimulation (tDCS) will be administered using a battery-powered stimulator. The anode will be positioned over the left dorsolateral prefrontal cortex (DLPFC, F3) and the cathode over the right supraorbital region (Fp2). The stimulation intensity will be set at 2.0 mA, featuring a 30-second linear ramp-up at the beginning and a 30-second ramp-down at the end of each session.

Each participant will receive a total of three 20-minute sessions of active tDCS. The first session will be provided at 40 minutes after extubation in the post-anesthesia care unit. Two other sessions will be provided on postoperative days 1 and 2 (between 10:00 and 12:00 am).

Other Names:
  • Active transcranial direct current stimulation
Drug: Placebo

Placebo (normal saline) will be administered after anesthesia induction, firstly as a loading dose at a rate of [0.4 x body weight (kg)] mL/h for 30 minutes, followed by a maintenance infusion at a rate of [0.1 x body weight (kg)] mL/h until one hour before expected end surgery.

Postoperative patient-controlled analgesia will be established with a 100 mL mixture (containing 1.0 μg/mL sufentanil in normal saline), programmed to deliver 2-mL boluses with an 8-minute lockout interval and an 1-mL/h background infusion, and provided for 48 hours (at least 24 hours).

Other Names:
  • Normal saline
Placebo Comparator: Placebo + sham tDCS
Participants will receive placebo (normal saline) and sham (placebo) transcranial direct current stimulation (tDCS).
Device: Sham tDCS

Sham transcranial direct current stimulation (tDCS) will be administered using a battery-powered stimulator. The anode will be positioned over the left dorsolateral prefrontal cortex (DLPFC, F3) and the cathode over the right supraorbital region (Fp2). To ensure blinding, the device will deliver a initial 30-second ramp-up to 2.0 mA followed immediately by a 30-second ramp-down to 0 mA. The device remains "ON" for the remaining 19 minutes with no effective current output, mimicking the peripheral scalp sensation without delivering cortical modulation.

Each participant will receive a total of three 20-minute sessions of sham tDCS. The first session will be provided at 40 minutes after extubation in the post-anesthesia care unit. Two other sessions will be provided on postoperative days 1 and 2 (between 10:00 and 12:00 am).

Other Names:
  • Sham transcranial direct current stimulation
Drug: Placebo

Placebo (normal saline) will be administered after anesthesia induction, firstly as a loading dose at a rate of [0.4 x body weight (kg)] mL/h for 30 minutes, followed by a maintenance infusion at a rate of [0.1 x body weight (kg)] mL/h until one hour before expected end surgery.

Postoperative patient-controlled analgesia will be established with a 100 mL mixture (containing 1.0 μg/mL sufentanil in normal saline), programmed to deliver 2-mL boluses with an 8-minute lockout interval and an 1-mL/h background infusion, and provided for 48 hours (at least 24 hours).

Other Names:
  • Normal saline

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Incidence of postoperative neurocognitive disorders (pNCD) at 3 months
Time Frame: At 3 months after surgery

Cognitive function will be assessed at baseline and at 3 months after surgery using the Telephone version of Montreal Cognitive Assessment (T-MoCA; scores range from 0 to 22, with higher scores indicating better cognitive function）.

Postoperative neurocognitive disorders (pNCD) is defined as: a |Z| value of decline in T-MoCA score ≥1.96. Z value = [(change from baseline in T-MoCA score in a surgical patient - mean change from baseline in T-MoCA scores in the non-surgical group)] / (standard deviation of change from baseline in T-MoCA scores in the non-surgical group).
At 3 months after surgery

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Event-free survival
Time Frame: Up to 1 year after surgery of the last enrolled patient
Time interval from index surgery to cancer recurrence/metastasis/progression, new-onset cancer, new-onset serious illness (requiring hospitalization), or all-cause death, whichever comes first.
Up to 1 year after surgery of the last enrolled patient

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Overall survival
Time Frame: Up to 1 year after surgery of the last enrolled patient
Time interval from index surgery to all-cause death.
Up to 1 year after surgery of the last enrolled patient
Recurrence-free survival
Time Frame: Up to 1 year after surgery of the last enrolled patient
Time interval from index surgery to cancer recurrence/metastasis/progression or all-cause death, whichever comes first.
Up to 1 year after surgery of the last enrolled patient
Activities of daily living score
Time Frame: At 3 months, 6 months, and 1 year after surgery
Daily living activities will be assessed with the activities of daily living (ADL; scores range from 1 to 56, with higher scores indicating worse ability of daily living).
At 3 months, 6 months, and 1 year after surgery
Incidence of postoperative neurocognitive disorders (pNCD) at 6 months and 1 year
Time Frame: At 6 months and 1 year after surgery

Cognitive function will be assessed at baseline and at 6 months and 1 year after surgery using the Telephone version of Montreal Cognitive Assessment (T-MoCA; scores range from 0 to 22, with higher scores indicating better cognitive function）.

Postoperative neurocognitive disorders (pNCD) is defined as: a |Z| value of decline in T-MoCA score ≥1.96. Z value = [(change from baseline in T-MoCA score in a surgical patient - mean change from baseline in T-MoCA scores in the non-surgical group)] / (standard deviation of change from baseline in T-MoCA scores in the non-surgical group).
At 6 months and 1 year after surgery

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Peking University First Hospital

Collaborators

Second Affiliated Hospital, School of Medicine, Zhejiang University
Fujian Medical University Union Hospital
Zhejiang University
Peking University Shenzhen Hospital
The First Affiliated Hospital of Air Force Medicial University

Investigators

  • Principal Investigator: Dong-Xin Wang, MD, PhD, Peking University First Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

June 1, 2026

Primary Completion (Estimated)

June 1, 2030

Study Completion (Estimated)

June 1, 2031

Study Registration Dates

First Submitted

May 3, 2026

First Submitted That Met QC Criteria

May 3, 2026

First Posted (Actual)

May 8, 2026

Study Record Updates

Last Update Posted (Actual)

May 12, 2026

Last Update Submitted That Met QC Criteria

May 7, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2026-1219-LT
  • 82293644 (Other Grant/Funding Number: National Natural Science Foundation of China)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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