CHECK-NIRS2D-Study

September 28, 2026 updated by: Heinrich-Heine University, Duesseldorf

Influence of External Physiological and Behavioral Factors on Two-Dimensional Near-Infrared Spectroscopy-Based Imaging in Healthy Volunteers: A Controlled Experimental Study

The study investigates how external, physiological, and behavioral factors influence the measurement of regional tissue oxygenation using two-dimensional near-infrared spectroscopy (NIRS) imaging in healthy volunteers. It aims to improve the standardization and reliability of this non-invasive method for assessing microvascular perfusion and tissue oxygenation.

The study also examines the effects of temporary vascular occlusion, ambient temperature, physical activity, caffeine consumption, and nicotine consumption on NIRS-based tissue oxygenation measurements. The findings are intended to establish a standardized measurement protocol for future clinical research and the assessment of microvascular perfusion in critically ill patients.

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.

Detailed Description

The study is a prospective, monocentric, controlled experimental study in healthy volunteers. It examines how external conditions, physiological states, and everyday behaviors influence measurements obtained with two-dimensional near-infrared spectroscopy (2D-NIRS). The imaging method is intended to assess local tissue oxygenation and microvascular perfusion non-invasively.

Detailed study description

  1. General purpose

    The CHECK-NIRS2D study is a prospective, monocentric, controlled experimental study conducted at the University Hospital Düsseldorf. It investigates how external conditions, physiological states, and behavioral factors influence measurements of local tissue oxygenation obtained using two-dimensional near-infrared spectroscopy (2D-NIRS).

    The study uses the SnapshotNIR camera system (KD203, Kent Imaging Inc., Calgary, Canada). This non-invasive method produces spatially resolved images of tissue oxygenation, allowing the investigators to examine not only the overall oxygenation of a tissue region but also possible differences in perfusion between individual areas.

    The study is intended as physiological and methodological research. It does not evaluate the therapeutic efficacy or safety of the device and does not provide a direct medical benefit to participants. Its longer-term objective is to develop a standardized protocol for future studies involving patients with acute or chronic diseases, particularly in emergency and intensive-care medicine.

  2. Participants

    The study plans to include healthy adults:

    • Age: 20-40 years
    • Male and female participants
    • Voluntary written informed consent after detailed explanation
    • No acute illness at the time of examination
    • No relevant cardiovascular, pulmonary, renal, vascular, or neurological history
    • No relevant disease, previous surgery, or acute pathology affecting the examined upper limb
    • Resting oxygen saturation of at least 95%
    • No relevant resting hypotension or hypertension

    Participants who regularly use medication affecting the cardiovascular system or blood coagulation, as well as pregnant or breastfeeding participants, are excluded.

    Five substudies, designated A-E, are planned. Approximately 20 participants per experimental group are intended. Participants may take part in more than one substudy, but this is voluntary. The order of experimental protocols is randomized, and a recovery period of at least 60 minutes is planned between measurements of the same extremity, except where the caffeine- and nicotine-specific protocols require a different arrangement.

  3. General examination procedure

The examinations generally take place with the participant sitting upright. The arm to be examined is positioned beside the body, with the palm facing upwards and the elbow approximately at the level of the lower end of the sternum.

The following measurements are generally performed:

  • 2D-NIRS imaging of the hand or upper extremity
  • Measurement of regional and microvascular tissue oxygenation.
  • Repeated imaging during baseline, temporary ischemia, and reperfusion.
  • Vascular occlusion test (VOT)
  • A pneumatic blood-pressure cuff is inflated to 200 mmHg.
  • The radial pulse is checked at one-minute intervals to confirm interruption of arterial blood flow.
  • Depending on the protocol, the occlusion lasts three, five, or six minutes.
  • The cuff is then deflated, allowing reperfusion of the extremity.
  • Blood-pressure measurement
  • Systolic blood pressure
  • Diastolic blood pressure
  • Mean arterial pressure
  • Pulse oximetry
  • Measurement of peripheral oxygen saturation, or SpO₂.
  • Heart-rate measuremen
  • Capillary reperfusion time
  • Assessment of the time required for capillary perfusion to return.
  • Subjective pain assessment
  • Pain or discomfort during the vascular occlusion test is recorded using a Numeric Rating Scale (NRS).
  • Confocal retinal funduscopy
  • In specified experimental groups, the retinal microcirculation is examined using fully automated, confocal funduscopy.

Depending on the substudy, this is performed at baseline and at the end of the experiment or repeatedly during control measurements.

During the standard VOT protocols, heart rate, blood pressure, SpO₂, and pain are generally recorded at one-minute intervals. NIRS imaging and capillary reperfusion measurements are performed at shorter intervals during ischemia and early reperfusion, including every 30 seconds during ischemia and during the first five minutes after reperfusion begins.

The protocol includes:

  • Smokers and non-smokers
  • VOT and control conditions
  • Measurements after abstinence
  • A specific acute nicotine-exposure condition in smokers
  • NIRS imaging, VOT-related measurements, blood pressure, heart rate, SpO₂, pain assessment, and capillary reperfusion measurements are performed. In selected groups, retinal funduscopy is conducted at the beginning and end of the experiment.

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.
20

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 Contact Backup

Study Locations

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

20 years to 40 years (Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

healthy volunteers

Description

Inclusion Criteria:

  • Healthy volunteers aged 20-40 years
  • Written informed consent
  • Ability to understand and comply with the study procedures

Exclusion Criteria:

  • Age below 20 years or above 40 years
  • Cardiovascular disease or other relevant medical conditions
  • current medication, where relevant to the study procedures
  • contraindication to or inability to undergo the planned examinations
  • Any condition that may interfere with the study procedures or outcome measurements

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

  • Observational Models: COHORT
  • Time Perspectives: PROSPECTIVE

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

predefined measurements
Control Group

Standardized 2D-NIRS imaging at rest under predefined reference conditions, including the protocol-defined VOT.

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
microvascular tissue oxygenation
Time Frame: within 20 Minutes of ischemia/reprefusion protocol measurement

StO₂, expressed as a percentage
within 20 Minutes of ischemia/reprefusion protocol measurement

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
Retinal funduscopy parameters
Time Frame: within 20 Minutes of ischemia/reprefusion protocol measurement

measured by NIRS
within 20 Minutes of ischemia/reprefusion protocol measurement

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.
Heinrich-Heine University, Duesseldorf

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Chair: Malte Kelm, MD, Division of Cardiology, Pulmonary Disease and Vascular Medicine at University Hospital Duesseldorf

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.
July 28, 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, 2027

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.
March 1, 2027

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).
September 28, 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.
September 28, 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.
October 2, 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.
October 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.
September 28, 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.
September 1, 2026

More Information

Terms related to this study

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.
  • CHECK-NIRS2D-Study

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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