Cerebral Blood Flow and Ventilatory Responses During Sleep in Normoxia and Intermittent Hypoxia

April 27, 2026 updated by: Marc Poulin, University of Calgary

Role of Cerebral Blood Flow on Ventilatory Stability During Sleep in Normoxia and Intermittent Hypoxia

A prospective double blind, placebo-controlled, randomized cross-over trial to evaluate the effect of lowering cerebral blood flow on the ventilatory chemoreflexes (acute hypoxic and hypercapnic ventilatory responses).

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.

Detailed Description

The investigators will explore the relationship between changes in Cerebral Blood Flow (CBF) and ventilatory chemoreflexes i.e. Acute Ventilatory Response to Hypoxia (AHVR) and Acute Hypercapnic Ventilatory Response (HCVR) before, during and after sleep under normoxic conditions and sleep accompanied by isocapnic Intermittent Hypoxia (IH) among healthy human study participants.

A pharmacological intervention will be utilized to manipulate the CBF in a randomized order. The study participants will also be randomly assigned the order to sleep either under normoxia or IH exposure. The experiments will be separated from one another with an interval of sufficient drug and IH exposure washout period. The venous blood samples and urinary samples will be collected for the vascular biomarkers.

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 (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.
12

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.
  • Phase 2
  • Phase 1

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
      • Calgary, Alberta, Canada, T2N 4N1
        • Recruiting
        • University of Calgary
        • Contact:
          • Chair, Conjoint Ethics Board
          • Phone Number: chreb@ucalgary.ca

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 45 years (Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Healthy adults
  • 18 - 45 years of age
  • Living in Calgary for the past one year
  • Have no medical condition or should not be taking any blood pressure medications.
  • The participant should not be lactose intolerant

Exclusion Criteria:

  • Cerebrovascular, cardio-respiratory, renal and metabolic diseases
  • Bleeding disorders and upper gastrointestinal diseases e.g. peptic ulcer disease
  • Pregnancy, obese and sleep-disordered breathing
  • Drug allergies to non-steroidal anti-inflammatories
  • Currently smoking

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: Double

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.
Active Comparator: CBF Lowering and Normoxia Sleep
Study participants will take drug lowering Cerebral Blood Flow (CBF) and sleep under room air i.e. normoxia exposure.
Drug: Drug Lowering Cerebral Blood Flow (CBF) and Normoxia Sleep
The study participants will take Cerebral Blood Flow (CBF) lowering drug and sleep under Normoxia Exposure
Other Names:
  • Cerebral Blood Flow changes and Normoxia Sleep
Experimental: CBF Lowering and IH Sleep
Study participants will take drug lowering Cerebral Blood Flow (CBF) and sleep under Intermittent Hypoxia (IH) exposure.
Drug: Drug Lowering CBF and Intermittent Hypoxia Sleep
The study participants will take Cerebral Blood Flow (CBF) lowering drug and sleep under Intermittent Hypoxia (IH) Exposure
Other Names:
  • CBF changes and Intermittent Hypoxia Sleep
Sham Comparator: Placebo and Normoxia Sleep
Study participants will take Placebo that has no effect on Cerebral Blood Flow (CBF) and sleep under room air i.e. normoxia exposure.
Drug: Placebo and Normoxia Sleep
The study participants will take Placebo and sleep under Normoxia Exposure
Other Names:
  • Cerebral Blood Flow (CBF) with Placebo in Normoxia Sleep
Placebo Comparator: Placebo and IH Sleep
Study participants will take Placebo that has no effect on Cerebral Blood Flow (CBF) and sleep under Intermittent Hypoxia (IH) exposure.
Drug: Placebo and Intermittent Hypoxia Sleep
The study participants will take Placebo and sleep under Intermittent Hypoxia (IH) Exposure
Other Names:
  • CBF with Placebo in Intermittent Hypoxia Sleep

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
Changes in cerebral blood flow and ventilatory chemoreflexes
Time Frame: ~18 months (from the starting time of recruiting study participants)
The relationship between changes in cerebral blood flow (CBF) and ventilatory chemoreflexes (acute hypoxic and hypercapnic ventilatory responses) before and after sleeping under normoxia and intermittent hypoxia exposure among healthy human study participants.
~18 months (from the starting time of recruiting study participants)
Cerebral blood flow responses and ventilatory chemoreflexes during sleep
Time Frame: ~18 months (from the starting time of recruiting study participants)
The relationship between cerebral blood flow (CBF) changes and ventilatory chemoreflexes (acute hypoxic and hypercapnic ventilatory responses) during sleep under normoxia and intermittent hypoxia exposure among healthy human study participants.
~18 months (from the starting time of recruiting study participants)

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
Changes in reactive oxygen species and vascular biomarkers
Time Frame: ~24 months (from the starting time of recruiting study participants)
The changes in vascular biomarkers such as nitric oxide, reactive oxygen species and exosome analysis or urinary prostaglandins before and after sleep under normoxia and intermittent hypoxia exposure with cerebral blood flow changes.
~24 months (from the starting time of recruiting study participants)

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 Calgary

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.
January 1, 2023

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.
December 30, 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.
December 30, 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).
August 6, 2017

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.
August 16, 2017

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.
August 21, 2017

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 1, 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.
April 27, 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.
April 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.
  • REB13-0880

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

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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