The Impact of Carbon Monoxide and Altitude on Vascular Function (CarMA)

May 18, 2022 updated by: University of Alberta
The CarMA (Carbon Monoxide and Altitude) Study aims to observe the vascular effects of carbon monoxide exposure at low and high altitudes.

Study Overview

Status

Status

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

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.

Detailed Description

Each year, millions of people make journeys from low altitude regions to high altitude for recreation, travel, and religious pilgrimage. Carbon monoxide (CO) is commonly associated with cigarette smoke, exhaust fumes, and is viewed as a life-threatening toxic gas. Exposure to CO occurs during travel to and during activities common in high-altitude travel and pilgrimage including vehicle fumes, incense, and second-hand smoke exposure. High altitude exposure and CO exposure have been observed independently to have complex and opposing effects on vascular endothelial function. Observation of these stimuli together in a controlled environment may allow for further understanding of the underlying mechanisms of vascular physiology and adaptations to both high-altitude and CO exposure. The CarMA (Carbon Monoxide and Altitude) Study aims to observe the vascular effects of carbon monoxide exposure at low and high altitudes. Recently, other studies have showed a significant improvement in flow mediated dilation (FMD) with acute exposure to low levels of CO To date, no research has been presented concerning the effect of CO on vascular function at altitude. The present study aims to observe the effect of acute carbon monoxide exposure on 1) flow mediated dilation, 2) conduit artery flow in exercise induced reactive hyperemia at sea level and at altitude, and 3) the effect of CO on vascular function in a high altitude dwelling (sherpa) population.

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.
Interventional

Enrollment (Actual)

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.
19

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

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

Study Locations

  • Canada
    • Alberta
      • Edmonton, Alberta, Canada, T6G 2R3
        • University of Alberta

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

18 years to 50 years (Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Between the ages of 18-50 years
  • No medical history of cardiovascular, respiratory, nervous system, or metabolic disease.
  • Women must be pre-menopausal.

Exclusion Criteria:

  • Participants with any known cardiovascular, respiratory, nervous system, or metabolic disease.
  • Having travelled above 2,000m within 1 month of testing at low and high altitude.
  • Women who are pregnant, confirmed by a pregnancy test.
  • Women who are post-menopausal.
  • Participants that are classified as obese (body mass index > 30 kg/m2).
  • Participants who are current daily smokers.
  • Participants that are currently taking monoamine (MAO) inhibitors, or tricyclic antidepressants.

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: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
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.
Sham Comparator: Room Air Rebreathe
Rebreathe protocol will be completed with a room air syringe rather than CO
Drug: Sodium Nitroprusside
Bolus Sodium Nitroprusside (SNP) injection for endothelium-independent vasodilation measure
Other Names:
  • Nipride
Drug: Phenylephrine Hydrochloride
Bolus Phenylephrine injection for observe α1-mediated vasoconstriction during mild exercise
Experimental: CO Rebreathe
Rebreathe protocol will be completed with Carbon Monoxide
Drug: Sodium Nitroprusside
Bolus Sodium Nitroprusside (SNP) injection for endothelium-independent vasodilation measure
Other Names:
  • Nipride
Drug: Phenylephrine Hydrochloride
Bolus Phenylephrine injection for observe α1-mediated vasoconstriction during mild exercise
Other: Carbon monoxide rebreathe
Carbon monoxide exposure to increase blood (Carboxyhemoglobin) COHb safely to ~10%
Other Names:
  • Schmidt-Prommer blood volume test

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
Change in brachial artery diameter (assessed via ultrasound) following release of arterial occlusion
Time Frame: 15 minutes
Change in brachial artery diameter (assessed via ultrasound) following release of arterial occlusion
15 minutes
Blood flow within the brachial artery during rhythmic handgrip exercise.
Time Frame: 15 minutes
Blood flow within the brachial artery during rhythmic handgrip exercise.
15 minutes
Change in brachial artery conductance following an infusion of phenylephrine
Time Frame: 5 min
Change in brachial artery conductance following an infusion of phenylephrine
5 min

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.
University of Alberta

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.
  • Principal Investigator: Sean van Diepen, MD, MSc, University of Alberta
  • Principal Investigator: Craig Steinback, PhD, University of Alberta

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 (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.
June 10, 2021

Primary Completion (Actual)

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.
August 1, 2021

Study Completion (Actual)

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 18, 2022

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).
May 6, 2021

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.
June 8, 2021

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.
June 16, 2021

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.
May 25, 2022

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.
May 18, 2022

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.
June 1, 2021

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.
  • Pro00096251

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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