Cerebral Oxygen Consumption Response to Increased Oxygen Supply and Postoperative Delirium in Older Surgical Patients

March 29, 2026 updated by: Seoul National University Bundang Hospital

Association Between Cerebral Oxygen Consumption Responsiveness to Increased Oxygen Supply and Postoperative Delirium: A Prospective Observational Study Using Functional Near-Infrared Spectroscopy

The goal of this observational study is to learn whether the brain's ability to use oxygen during surgery is associated with postoperative delirium in adults aged 65 years and older undergoing general anesthesia.

The main question it aims to answer is:

- Does reduced cerebral oxygen consumption responsiveness during surgery increase the risk of postoperative delirium in older patients?

Participants who are undergoing elective laparoscopic surgery under general anesthesia as part of their routine medical care will have brain oxygen levels measured during surgery using a non-invasive forehead sensor, and will be assessed for delirium for up to three days after surgery.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
80

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

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • South Korea
    • Gyeonggi-do
      • Seongnam-si, Gyeonggi-do, South Korea, 13620
        • Recruiting
        • Seoul National University Bundang Hospital
        • 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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Older Adult

Accepts Healthy Volunteers

N/A

Sampling Method

Probability Sample

Study Population

Participants will be recruited from patients scheduled for elective laparoscopic surgery at Seoul National University Bundang Hospital, a tertiary academic medical center in the Republic of Korea. Eligible patients will be identified during routine preoperative evaluation and approached for study participation prior to surgery.

Description

Inclusion Criteria:

  • Patients undergoing elective laparoscopic surgery under general anesthesia
  • Age 65 years or older

Exclusion Criteria:

  • Diagnosis of dementia or presence of delirium before surgery
  • Loss of capacity to provide informed consent
  • Moderate or severe cerebrovascular stenosis diagnosed before surgery
  • Moderate or severe obstructive or restrictive pulmonary dysfunction identified on preoperative pulmonary function testing
  • Requirement for supplemental oxygen therapy before surgery
  • History of neurological disorders (e.g., Parkinson's disease, stroke) or prior brain surgery
  • Severe hepatic dysfunction (AST or ALT > 120 IU/L)
  • Severe renal dysfunction (estimated GFR < 15 mL/min/1.73 m²)
  • Persistent severe hemodynamic instability (mean arterial pressure < 60 mmHg)
  • Skin conditions preventing placement of the forehead fNIRS sensor
  • Combined surgical procedures performed concurrently
  • Planned postoperative admission to the intensive care unit

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

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Older patients undergoing elective laparoscopic surgery
Adults aged 65 years and older undergoing elective laparoscopic surgery under general anesthesia will be prospectively observed. During surgery, cerebral oxygen levels will be measured using a non-invasive forehead sensor to assess the brain's oxygen utilization response within the range of routine anesthesia care. Participants will be followed for up to three days after surgery to evaluate the occurrence of postoperative delirium.
Other: Intraoperative Cerebral Oxygen Utilization Assessment
Cerebral oxygenation will be monitored intraoperatively using a non-invasive forehead sensor based on functional near-infrared spectroscopy technology. During general anesthesia, the fraction of inspired oxygen (FiO₂) may be temporarily adjusted within the standard clinical range used in routine anesthesia care to evaluate the brain's oxygen utilization response. No experimental oxygen levels or additional therapeutic interventions will be administered beyond standard clinical practice.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Incidence of Postoperative Delirium
Time Frame: Up to 3 days after surgery
Postoperative delirium diagnosed using 3D-CAM conducted in the post-anesthesia care unit and hospital ward. Delirium will be defined as at least one positive assessment during the first three postoperative days.
Up to 3 days after surgery

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Intraoperative Cerebral Oxygen Utilization Response (ΔHbO-HbR)
Time Frame: During surgery
Change in the difference between oxygenated hemoglobin (HbO) and deoxygenated hemoglobin (HbR), calculated as Δ(HbO-HbR), measured intraoperatively using functional near-infrared spectroscopy during variations in inspired oxygen concentration within the clinically applied range.
During surgery

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Predictive Performance of ΔHbO-HbR for Postoperative Delirium
Time Frame: Up to 3 days after surgery
Predictive accuracy of intraoperative Δ(HbO-HbR) for postoperative delirium assessed using receiver operating characteristic (ROC) curve analysis. The area under the ROC curve (AUC) will be calculated to quantify discrimination.
Up to 3 days after surgery

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Seoul National University Bundang Hospital

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 (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
March 11, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
March 1, 2028

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
May 1, 2028

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
March 3, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 8, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
March 11, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 2, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 29, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
March 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • B-2602-1024-002

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

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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