Obstructive Sleep Apnea of AdultPhase 1/2NCT03255408
Cerebral Blood Flow and Ventilatory Responses During Sleep in Normoxia and Intermittent Hypoxia
A Phase 1/2 study testing Drug Lowering Cerebral Blood Flow (CBF) and Normoxia Sleep and Drug Lowering CBF and Intermittent Hypoxia Sleep in people with Obstructive Sleep Apnea of Adult and Hypoxia, Brain, run by University of Calgary at 1 site in Canada.
Trial summary
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). Read more about this study
- Who is it for?
- Ages 18 to 45 yearsHealthy volunteers can take part
- Conditions the study is for
- Obstructive Sleep Apnea of Adult, Hypoxia, Brain, Sleep Apnea
- What is being tested?
- Drug Lowering Cerebral Blood Flow (CBF) and Normoxia Sleep and Drug Lowering CBF and Intermittent Hypoxia Sleep
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 12 participants
- Where
- 1 siteCanada
- Study dates
- 1 Jan 2023to 30 Dec 2027
- Phase
- Phase 1/2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 45 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- 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
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Canada1 site, 1 recruiting
- Recruiting
University of Calgary
Calgary, Alberta, T2N 4N1
Chair, Conjoint Ethics Board, chreb@ucalgary.ca
About this study
Official title: 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).
Read the 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.
- Conditions
- Obstructive Sleep Apnea of Adult, Hypoxia, Brain, Sleep Apnea, Sleep Disorder, Stroke, Blood Pressure
- Being tested
- Drug Lowering Cerebral Blood Flow (CBF) and Normoxia Sleep, Drug Lowering CBF and Intermittent Hypoxia Sleep, Placebo and Normoxia Sleep, Placebo and Intermittent Hypoxia Sleep
- Medical subject headings
- Hypoxia, Brain, Sleep Apnea Syndromes, Sleep Wake Disorders, Stroke
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Drug Lowering Cerebral Blood Flow (CBF) and Normoxia SleepDrug
Also called Cerebral Blood Flow changes and Normoxia Sleep
The study participants will take Cerebral Blood Flow (CBF) lowering drug and sleep under Normoxia Exposure
Drug Lowering CBF and Intermittent Hypoxia SleepDrug
Also called CBF changes and Intermittent Hypoxia Sleep
The study participants will take Cerebral Blood Flow (CBF) lowering drug and sleep under Intermittent Hypoxia (IH) Exposure
Placebo and Normoxia SleepDrug
Also called Cerebral Blood Flow (CBF) with Placebo in Normoxia Sleep
The study participants will take Placebo and sleep under Normoxia Exposure
Placebo and Intermittent Hypoxia SleepDrug
Also called CBF with Placebo in Intermittent Hypoxia Sleep
The study participants will take Placebo and sleep under Intermittent Hypoxia (IH) Exposure
| Study group | Role | What they receive |
|---|---|---|
| CBF Lowering and Normoxia Sleep | Active comparator | Study participants will take drug lowering Cerebral Blood Flow (CBF) and sleep under room air i.e. normoxia exposure. Receives: Drug: Drug Lowering Cerebral Blood Flow (CBF) and Normoxia Sleep |
| CBF Lowering and IH Sleep | Experimental | Study participants will take drug lowering Cerebral Blood Flow (CBF) and sleep under Intermittent Hypoxia (IH) exposure. Receives: Drug: Drug Lowering CBF and Intermittent Hypoxia Sleep |
| Placebo and Normoxia Sleep | Sham comparator | Study participants will take Placebo that has no effect on Cerebral Blood Flow (CBF) and sleep under room air i.e. normoxia exposure. Receives: Drug: Placebo and Normoxia Sleep |
| Placebo and IH Sleep | Placebo comparator | Study participants will take Placebo that has no effect on Cerebral Blood Flow (CBF) and sleep under Intermittent Hypoxia (IH) exposure. Receives: Drug: Placebo and Intermittent Hypoxia Sleep |
What is being measured
The primary outcome is the main question the study is designed to answer.
Changes in cerebral blood flow and ventilatory chemoreflexes
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.
Measured: ~18 months (from the starting time of recruiting study participants)
Cerebral blood flow responses and ventilatory chemoreflexes during sleep
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.
Measured: ~18 months (from the starting time of recruiting study participants)
Secondary outcomes (1)
Changes in reactive oxygen species and vascular biomarkers
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.
Measured: ~24 months (from the starting time of recruiting study participants)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Aug 2017
- Study start1 Jan 2023
- Primary completion30 Dec 2027 (estimated)
- Study completion30 Dec 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Obstructive Sleep Apnea of AdultStudies of the same condition, open and under way.
- More trials run by University of CalgaryThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1/2
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 12 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Calgary
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Marc Poulin, University of Calgary
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03255408
- Sponsor's protocol ID
- REB13-0880
- Status last verified
- Apr 2026
- First submitted
- 6 Aug 2017
- Last updated
- 1 May 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 1 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Role of Cerebral Blood Flow on Ventilatory Stability During Sleep in Normoxia and Intermittent Hypoxia
- ClinicalTrials.gov ID
- NCT03255408
- Acronym / sponsor ID
- REB13-0880
- Conditions
- Obstructive Sleep Apnea of Adult, Hypoxia, Brain, Sleep Apnea, Sleep Disorder, Stroke, Blood Pressure
- Phase
- Phase 1/2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 12 participants (estimated)
- Lead sponsor
- University of CalgaryUniversity, hospital or other
- Study start
- 1 Jan 2023 (actual)
- Primary completion
- 30 Dec 2027 (estimated)
- Study completion
- 30 Dec 2027 (estimated)
- First posted
- 21 Aug 2017 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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).
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 design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| CBF Lowering and Normoxia Sleep | Active comparator | Drug: Drug Lowering Cerebral Blood Flow (CBF) and Normoxia SleepStudy participants will take drug lowering Cerebral Blood Flow (CBF) and sleep under room air i.e. normoxia exposure. |
| CBF Lowering and IH Sleep | Experimental | Drug: Drug Lowering CBF and Intermittent Hypoxia SleepStudy participants will take drug lowering Cerebral Blood Flow (CBF) and sleep under Intermittent Hypoxia (IH) exposure. |
| Placebo and Normoxia Sleep | Sham comparator | Drug: Placebo and Normoxia SleepStudy participants will take Placebo that has no effect on Cerebral Blood Flow (CBF) and sleep under room air i.e. normoxia exposure. |
| Placebo and IH Sleep | Placebo comparator | Drug: Placebo and Intermittent Hypoxia SleepStudy participants will take Placebo that has no effect on Cerebral Blood Flow (CBF) and sleep under Intermittent Hypoxia (IH) exposure. |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- 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
Key exclusion criteria (5 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Drug Lowering Cerebral Blood Flow (CBF) and Normoxia SleepAlso: Cerebral Blood Flow changes and Normoxia SleepThe study participants will take Cerebral Blood Flow (CBF) lowering drug and sleep under Normoxia Exposure | Drug | CBF Lowering and Normoxia Sleep |
| Drug Lowering CBF and Intermittent Hypoxia SleepAlso: CBF changes and Intermittent Hypoxia SleepThe study participants will take Cerebral Blood Flow (CBF) lowering drug and sleep under Intermittent Hypoxia (IH) Exposure | Drug | CBF Lowering and IH Sleep |
| Placebo and Normoxia SleepAlso: Cerebral Blood Flow (CBF) with Placebo in Normoxia SleepThe study participants will take Placebo and sleep under Normoxia Exposure | Drug | Placebo and Normoxia Sleep |
| Placebo and Intermittent Hypoxia SleepAlso: CBF with Placebo in Intermittent Hypoxia SleepThe study participants will take Placebo and sleep under Intermittent Hypoxia (IH) Exposure | Drug | Placebo and IH Sleep |
Primary outcome
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.
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.
1 secondary outcome
Changes in reactive oxygen species and vascular biomarkers
Time frame: ~24 months (from the starting time of recruiting study participants)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 1 May 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1/2 study testing Drug Lowering Cerebral Blood Flow (CBF) and Normoxia Sleep and Drug Lowering CBF and Intermittent Hypoxia Sleep in people with Obstructive Sleep Apnea of Adult and Hypoxia, Brain, run by University of Calgary at 1 site in Canada.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 1 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this combined phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Each site lists its own contact: choose the nearest one under Trial locations. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Changes in cerebral blood flow and ventilatory chemoreflexes (time frame: ~18 months (from the starting time of recruiting study participants)). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 1 May 2026.