Carbon Dioxide (CO2) and Cognitive Impairment

Carbon Dioxide (CO2): A Pilot Study of a Hypothesized Mechanism to Explain Cognitive Impairment

The purpose of the study is to better understand the biological mechanisms of carbon dioxide (CO2)-induced cognitive impairments.

Study Overview

• Status: Completed
• Conditions: Healthy
• Intervention / Treatment: Other: 2500 ppm Carbon Dioxide; Other: 600 ppm Carbon Dioxide

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Actual): 24
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Kathy Black, PhD; Phone Number: 848-445-6049; Email: kgblack@eohsi.rutgers.edu
• Study Contact Backup: Name: Alicia Legard; Phone Number: 848-445-6086; Email: abl104@eohsi.rutgers.edu

Study Locations

• United States
  • New Jersey
    • Piscataway, New Jersey, United States, 08854
      • Rutgers - EOHSI

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 30 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• History of COVID-19 vaccination
• Weigh at least 110 pounds

Exclusion Criteria:

• Colorblindness
• Inability to hear verbal instructions
• Cardiovascular disease, including a history of stroke
• Diabetes requiring the use of insulin
• Pregnancy
• Current asthma (an asthma attack within the past five years)
• Medications for or history of anxiety disorder diagnosis or panic attacks
• Medications which may affect cognition such as beta-blockers and CNS depressants

Temporary Exclusion Criteria

• Respiratory symptoms in the previous four weeks
• Use of sedating cold/allergy medications in the previous week
• Use of marijuana in the previous week
• Consumption of alcohol in the previous 24 hours

Additional Exclusion Criteria for Subjects undergoing the fMRI scan:

• History of head trauma or neurosurgery or neurological disorder
• Ferrous metal implanted in or on the body, electrical devices such as a pacemaker, nonremovable ferrous jewelry
• Surgical pins or plates above the neck
• History of eye injury involving metallic materials, shavings in eyes, or welding without a face mask
• Lead or iron tatoos
• Claustrophobia
• Back problems that would prevent the subject from laying still comfortably for up to 90 minutes

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: High CO2 Exposure first, then low CO2 exposure second.; 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.	Other: 2500 ppm Carbon Dioxide; 2.5 hour exposure to 2500 ppm carbon dioxide; Other: 600 ppm Carbon Dioxide; 2.5 hour exposure to 600 ppm carbon dioxide
Sham Comparator: Low CO2 Exposure first, then high CO2 exposure second.; 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.	Other: 2500 ppm Carbon Dioxide; 2.5 hour exposure to 2500 ppm carbon dioxide; Other: 600 ppm Carbon Dioxide; 2.5 hour exposure to 600 ppm carbon dioxide

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in PMN (polymorphonuclear leukocyte) activation from pre-exposure to post-exposure	Using blood samples collected pre- and post-exposure, PMN activation will be assessed by measurement of oxidative burst (oxygen consumption rate), glycolytic function (extracellular acidification rate) and caspase-1 activity (assessed by fluorometric assay).	Immediately before and immediately after each exposure

Collaborators and Investigators

• Sponsor: Rutgers, The State University of New Jersey
• Investigators: Principal Investigator: Howard Kipen, MD, Professor

Study record dates

Study Major Dates

• Study Start (Actual): July 14, 2022
• Primary Completion (Actual): January 25, 2024
• Study Completion (Actual): January 25, 2024

Study Registration Dates

• First Submitted: January 24, 2022
• First Submitted That Met QC Criteria: March 10, 2022
• First Posted (Actual): March 23, 2022

Study Record Updates

• Last Update Posted (Actual): February 9, 2024
• Last Update Submitted That Met QC Criteria: February 7, 2024
• Last Verified: February 1, 2024

More Information

Terms related to this study

• Keywords: Cognitive Impairment; Carbon Dioxide
• Additional Relevant MeSH Terms: Mental Disorders; Neurocognitive Disorders; Cognition Disorders; Cognitive Dysfunction
• Other Study ID Numbers: Pro2021001570

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: There is no plan to make individual participant data available to other researchers.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No