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The purpose of the study is to better understand the biological mechanisms of carbon dioxide (CO2)-induced cognitive impairments.
Participants will complete 2 study visits. Each study visit will consist of a 2.5-hour exposure session. Concentrations of CO2 during the exposure session will be either 600 ppm (control) or 2500 ppm (exposure). The order of the exposure sessions will be randomized and the exposure sessions will be at least one week apart. Up to two participants will take part in each exposure session.
During each exposure a neurobehavioral assessment (Strategic Management Simulations or SMS) will be administered. Venous blood (30 mL) will be collected from subjects immediately before entering the chamber and immediately after the exposure. A subset of subjects (n=12) will also undergo a 60-minute fMRI scan. Another subset of subjects (up to 10) will not complete the SMS during the exposures but will undergo computer-assisted intravital microscopy (CAIM) to exam the conjunctival microvasculature before and after the exposure.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| High CO2 Exposure first, then low CO2 exposure second. | Experimental | At the first study visit the subject is exposed to 2500 ppm CO2 for 2.5 hours and at the second study visit the subject is exposed to 600 ppm CO2 for 2.5 hours. |
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| Low CO2 Exposure first, then high CO2 exposure second. | Sham Comparator | At the first study visit the subject is exposed to 600 ppm CO2 for 2.5 hours and at the second study visit the subject is exposed to 2500 ppm CO2 for 2.5 hours. |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| 2500 ppm Carbon Dioxide | Other | 2.5 hour exposure to 2500 ppm carbon dioxide |
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| Measure | Description | Time Frame |
|---|---|---|
| Change in PMN (Polymorphonuclear Leukocyte) Activation as Measured by Basal Oxygen Consumption (OCR) | Using blood samples collected 4 hours post-exposure, PMN activation was assessed by measurement of oxidative burst (oxygen consumption rate). | 4 hours after each exposure |
| Change in PMN (Polymorphonuclear Leukocyte) Activation as Measured by Total Stimulated Oxygen Consumption. | Using blood samples collected 4 hours post-exposure, PMN activation was assessed by measurement of total stimulated oxygen consumption. | 4 hours after each exposure |
| Change in PMN (Polymorphonuclear Leukocyte) Activation as Measured by Time to Peak (TTP) Oxygen Consumption | Using blood samples collected 4 hours post-exposure, PMN activation was assessed by measurement of time to peak (TTP) oxygen consumption. | 4 hours after each exposure |
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Inclusion Criteria:
Exclusion Criteria:
Temporary Exclusion Criteria
Additional Exclusion Criteria for Subjects undergoing the fMRI scan:
Additional Exclusion Criteria for Subjects undergoing CAIM
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| Name | Affiliation | Role |
|---|---|---|
| Howard Kipen, MD | Professor | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Rutgers - EOHSI | Piscataway | New Jersey | 08854 | United States |
There is no plan to make individual participant data available to other researchers.
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There were 27 participants that started the study. Of these, 26 completed the study by completing both study visits. One participant was withdrawn from the investigator due to a protocol deviation.
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| ID | Title | Description |
|---|---|---|
| FG000 | High CO2 Exposure First, Then Low CO2 Exposure Second | First exposure was High CO2 exposure (2500 ppm). Second exposure was Low CO2 exposure (600ppm). |
| FG001 | Low CO2 Exposure First, Then High CO2 Exposure Second | First exposure was the low CO2 exposure (600 ppm). Second exposure was the high CO2 (2500 ppm). |
| Title | Milestones | Reasons Not Completed | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Overall Study |
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| ID | Title | Description |
|---|---|---|
| BG000 | All Participants | All participants who were randomized to a first exposure (N=27) |
| Units | Counts |
|---|---|
| Participants |
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| Title | Description | Population Description | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Denominator Units Selected | Denominators | Classes |
|---|---|---|---|---|---|---|---|---|---|
| Age, Continuous | Age (in years) at consent | Demographics of all participants randomized to a first exposure were analyzed. |
| Type | Title | Description | Population Description | Reporting Status | Anticipated Posting Date | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Time Frame | Units Analyzed | Denominator Units Selected | Arm/Group Information | Denominators | Classes | Analyses | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Primary | Change in PMN (Polymorphonuclear Leukocyte) Activation as Measured by Basal Oxygen Consumption (OCR) | Using blood samples collected 4 hours post-exposure, PMN activation was assessed by measurement of oxidative burst (oxygen consumption rate). | Data from all subjects who completed both exposures were analyzed. | Posted | Mean | Standard Deviation | pmol/min | 4 hours after each exposure |
|
4 hours after each exposure
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| ID | Title | Description | Deaths (Affected) | Deaths (At Risk) | Serious Events (Affected) | Serious Events (At Risk) | Other Events (Affected) | Other Events (At Risk) |
|---|---|---|---|---|---|---|---|---|
| EG000 | All Participants | All participants who were randomized to a first exposure (N=27) |
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| Title | Organization | Phone | Extension | |
|---|---|---|---|---|
| Howard Kipen | Rutgers the State University of New Jersey | 848-445-6082 | kipen@eohsi.rutgers.edu |
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| Type | Includes Protocol | Includes SAP | Includes ICF | Document Label | Document Date | Document Uploaded Date | Document File Name |
|---|---|---|---|---|---|---|---|
| Prot | Yes | No | No | Study Protocol | Nov 18, 2024 | Feb 19, 2026 | Prot_001.pdf |
| SAP | No | Yes | No | Statistical Analysis Plan | Feb 5, 2026 | Feb 5, 2026 | SAP_002.pdf |
| ICF | No | No | Yes | Informed Consent Form | Nov 18, 2024 | Feb 19, 2026 | ICF_003.pdf |
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| ID | Term |
|---|---|
| D060825 | Cognitive Dysfunction |
| ID | Term |
|---|---|
| D003072 | Cognition Disorders |
| D019965 | Neurocognitive Disorders |
| D001523 | Mental Disorders |
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| 600 ppm Carbon Dioxide | Other | 2.5 hour exposure to 600 ppm carbon dioxide |
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| Mean |
| Standard Deviation |
| years |
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| Sex: Female, Male | Demographics of all participants randomized to a first exposure were analyzed. | Count of Participants | Participants |
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| Race (NIH/OMB) | Demographics of all participants randomized to a first exposure were analyzed. | Count of Participants | Participants |
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| Ethnicity (NIH/OMB) | Demographics of all participants randomized to a first exposure were analyzed. | Count of Participants | Participants |
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| Primary | Change in PMN (Polymorphonuclear Leukocyte) Activation as Measured by Total Stimulated Oxygen Consumption. | Using blood samples collected 4 hours post-exposure, PMN activation was assessed by measurement of total stimulated oxygen consumption. | Data from all 26 subjects who completed both exposures were analyzed. | Posted | Mean | Standard Deviation | nmole | 4 hours after each exposure |
|
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| Primary | Change in PMN (Polymorphonuclear Leukocyte) Activation as Measured by Time to Peak (TTP) Oxygen Consumption | Using blood samples collected 4 hours post-exposure, PMN activation was assessed by measurement of time to peak (TTP) oxygen consumption. | Data from all 26 subjects who completed both exposures were analyzed. | Posted | Mean | Standard Deviation | minutes | 4 hours after each exposure |
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| 0 |
| 27 |
| 0 |
| 27 |
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| 27 |
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