Neurogenic Orthostatic HypotensionNCT05908760
CO2 Rebreathing in nOH: A Proof-of-Concept Pilot Study
A study testing CO2 ReHaler in people with Neurogenic Orthostatic Hypotension and Autonomic Failure, run by University of Calgary at 1 site in Canada.
Trial summary
Neurogenic orthostatic hypotension (nOH) is a chronic condition associated with increased cardiovascular risk and reduced quality of life. On standing, patients with nOH experience a large reduction in blood pressure (BP; at least ≥20/10mmHg, but often much more), which is often accompanied by debilitating symptoms… Read more about this study
- Who is it for?
- Ages 18 to 100 years
- Conditions the study is for
- Neurogenic Orthostatic Hypotension, Autonomic Failure
- What is being tested?
- CO2 ReHaler
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 28 participants
- Where
- 1 siteCanada
- Study dates
- 30 Jul 2024to 31 Dec 2030
- Phase
- Interventional
- 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 100 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Age ≥18 years
- Male and Female
- Physician diagnosis of Neurogenic Orthostatic Hypotension
- Non-smokers.
- Able and willing to provide informed consent.
- Ability to travel to Libin Cardiovascular Institute Autonomic Testing Lab at the University of Calgary, Calgary, AB.
Who cannot join
- Medical therapies or medications which could interfere with testing of autonomic function
- Pregnant or breast-feeding females
- Subjects with chronic heart failure or severe pulmonary disease who are unable to climb one flight of stairs due to shortness of breath.
- Presence of failure of other organ systems or systemic illness that can affect autonomic function or the participant's ability to cooperate. These include dementia, alcohol and/or drug abuse, cerebrovascular disease, kidney or liver disease, surgical procedures where the nerves of the sympathetic nervous system have been cut.
- Other factors which in the investigator's opinion would prevent the participant from completing the protocol, including poor compliance during previous studies.
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
Satish R Raj, MD, 403-210-6152, autonomic.research@ucalgary.ca
Robert S Sheldon, MD, PhD, 403-220-8191, autonomic.research@ucalgary.ca
About this study
Official title: CO2 Rebreathing to Increase Blood Pressure in Neurogenic Orthostatic Hypotension: A Proof-of-Concept Pilot Study
Neurogenic orthostatic hypotension (nOH) is a chronic condition associated with increased cardiovascular risk and reduced quality of life. On standing, patients with nOH experience a large reduction in blood pressure (BP; at least ≥20/10mmHg, but often much more), which is often accompanied by debilitating symptoms and syncope. A previous study (unpublished) showed that hypercapnia significantly increases standing BP in patients with nOH. Human bodies naturally produce and exhale CO2. Rebreathe devices offer a simple, cost-effective technology to increase arterial CO2. In brief, rebreathe devices work by capturing expired CO2, which is then re-inhaled. The net effect is a transient increase in CO2. A CO2 rebreathing device may offer a novel hemodynamic therapy for patients with nOH.
This is a pilot, proof-of-concept study to evaluate a CO2 rebreather to improve blood pressure and orthostatic tolerance in patients with nOH. The hypothesis is that a rebreather will increase CO2 sufficiently enough to improve BP in patients with nOH.
Read more
Male and female patients (n=28) will be asked to complete two randomized 70° head-up tilt (HUT) tests breathing either room air or using a CO2 rebreather. Hemodynamics (BP, heart rate, stroke volume, brain blood flow) and orthostatic symptoms will be assessed throughout. Breath-by-breath data will include O2, CO2, respiration rate and tidal volume.
The primary outcome measure will be the magnitude of the BP response (ΔBP = HUT - Supine) during Room Air vs. Hypercapnia. The primary outcome will be compared between room air and hypercapnia using a paired t-test.
Read the detailed description
BACKGROUND: Neurogenic orthostatic hypotension (nOH) is a chronic condition associated with increased cardiovascular risk and reduced quality of life. On standing, patients with nOH experience a large reduction in blood pressure (BP; at least ≥20/10mmHg, but often much more), which is often accompanied by debilitating symptoms and syncope. nOH affects the elderly and patients with neurodegenerative diseases (e.g., Parkinson's disease, multiple system atrophy), neuropathies (e.g., diabetes), and neural injury (e.g., spinal cord injury).
In healthy controls, hypercapnia (i.e., high CO2) increases in sympathetic nerve activity and BP. Hypercapnia significantly increases supine and seated BP in patients with nOH, and a previous study (unpublished) showed that hypercapnia significantly increases standing BP in patients with nOH.
Human bodies naturally produce and exhale CO2. Rebreathe devices offer a simple, cost-effective technology to increase arterial CO2. In brief, rebreathe devices work by capturing expired CO2, which is then re-inhaled. The net effect is a transient increase in CO2. A CO2 rebreathing device may offer a novel hemodynamic therapy for patients with nOH.
OBJECTIVE: This is a pilot, proof-of-concept study to evaluate a CO2 rebreather to improve blood pressure and orthostatic tolerance in patients with nOH. The study hypothesis is that a rebreather will increase CO2 sufficiently enough to improve BP in patients with nOH.
METHODS: Male and female patients (n=28) will be recruited from the Calgary Autonomic Investigation and Management Clinic.
STUDY PROCEDURE Informed Consent: The informed consent will be sent by email to the patients in advance. The investigators will give each patient a chance to ask questions about the protocol and have these questions answered to their satisfaction. Written informed consent will be documented prior to engaging in study-related procedures.
Holding Pre-Existing Medications: Participants will be asked to hold their clinical medications on the day of the study testing, if possible, but this will not be mandatory. The investigators will make note of the medications used by each participant at the time of the study.
Study Day: Participants will be instrumented at least 2h post-prandial on an empty bladder. Participants will be asked to abstain from alcohol, caffeine, and exercise for a period of 12 hours prior to testing. Participants will be allowed to drink water on the morning of study. Upon lab arrival, a description of the study will be given and written informed consent will be attained if the individual chooses to participate in the study. A member of the research team will ask participants about current medications and other disorders they many have as part of the study inclusion/exclusion criteria. The investigators will also review all other inclusion/exclusion criteria for the study. All study equipment will be introduced to the participant, and then the investigators will begin to prepare for the study.
Participants will be asked to lie supine on the tilt table during instrumentation. Following instrumentation, the study will begin with a 10-minute baseline in the supine position. During this period, the investigators will track blood pressure, heart rate, brain blood flow velocity, fluid shifts, and respiratory pattern using the following equipment:
- Finger and arm blood pressure cuffs
- Skin electrodes to measure heart rate and fluid shifts
- A Transcranial Doppler (TCD) which will use a band around the head, with an ultrasound-like probe at the left and/or right temple
- Pulse oximeter on the finger to measure oxygen saturation
- Participants will be fitted with a mouthpiece to breathing into. The mouthpiece will be connected to a breathing bag that will capture the CO2 exhaled. The mouthpiece will also be connected to a tube that will measure respiratory rate, respiratory depth, CO2 and O2.
Following instrumentation, participants will complete up to two 70° head-up tilt (HUT) tests while breathing either normal room air or while breathing with the rebreather. Each HUT will last a maximum of 5 minutes, and when participants are not upright, the participants will be in the supine position. Participants will be asked to breathe with the rebreather until the measured CO2 increases between 5-10mmHg. Once CO2 is increased, HUT will begin. Participants will continue to breathe with the rebreather until the end of HUT.
The two HUT tests will be randomized and will consist of:
- HUT with Room Air
- HUT with ETCO2 levels increased 5-10mmHg above normal levels
The primary outcome measure will be the magnitude of the BP response (ΔBP = HUT - Supine) during Room Air vs. Hypercapnia. The primary outcome will be compared between room air and hypercapnia using a paired t-test.
- Being tested
- CO2 ReHaler
- Medical subject headings
- Pure Autonomic Failure
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
CO2 ReHalerDevice
The ReHaler captures expired CO2, which is then re-inhaled. The net effect is a transient increase in CO2.
| Study group | Role | What they receive |
|---|---|---|
| CO2 Rebreathing | Experimental | Participants will breathe with the rebreather in the supine position until CO2 levels increase between 5-10mmHg. Once CO2 levels are increased, participants will be tilted upright, and will continue to breathe with the rebreather during a 5-min HUT test Receives: Device: CO2 ReHaler |
| Room Air | No intervention | Participants will breathe room air in the supine position and during a 5-min HUT test |
What is being measured
The primary outcome is the main question the study is designed to answer.
Δ Blood Pressure (BP)
Magnitude of ΔBP (HUT-Supine) breathing room air vs CO2 rebreathe
Measured: The ΔBP (HUT-Supine) calculated as the average BP in the final two minutes of supine baseline and the average BP between minute 3 and 5 of HUT will be compared between room air and CO2 rebreathe
Secondary outcomes (2)
Δ Vanderbilt Orthostatic Symptom Score [Range: 0 (absent) to 10 (worst)]
Magnitude of Δ Vanderbilt Orthostatic Symptom Score (HUT-Supine) breathing room air vs CO2 rebreathe
Measured: The Δ Vanderbilt Orthostatic Symptom Score (symptoms at the 5th minute of HUT - symptoms at the 5th minute of supine rest) will be compared between room air vs CO2 rebreathe
Δ Cerebral Blood Flow Velocity (CBFv)
Magnitude of ΔCBFv (HUT-Supine) breathing room air vs CO2 rebreathe
Measured: The ΔCBFv (HUT-Supine) calculated as the average CBFv in the final two minutes of supine baseline and the average CBFv between minute 3 and 5 of HUT will be compared between room air and CO2 rebreathe
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Jun 2023
- Study start30 Jul 2024
- Primary completion31 Dec 2029 (estimated)
- Study completion31 Dec 2030 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (5)Papers the sponsor has linked to this study.
- Other trials for Neurogenic Orthostatic HypotensionStudies 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 N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Male and female NOH patients (n=28) will be recruited from the Calgary Autonomic Clinic. Participants will complete the following two randomized head-up tilt tests (HUT): * Room Air: Participants will breathe room air while supine and during a 5-min HUT test * CO2 rebreathing: Participants will breathe with the rebreather in the supine position until CO2 levels increase between 5-10mmHg. Once CO2 levels are increased, participants will be tilted upright, and will continue to breathe with the rebreather during a 5-min HUT test
- Masking
- None (open label)
- Enrolment
- 28 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Calgary
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Dr. Satish Raj, University of Calgary
- Investigators
- Satish R Raj, MD, Principal investigator, University of Calgary
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05908760
- Sponsor's protocol ID
- REB23-0791
- Status last verified
- Apr 2026
- First submitted
- 8 Jun 2023
- Last updated
- 5 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Freeman R, Abuzinadah AR, Gibbons C, Jones P, Miglis MG, Sinn DI. Orthostatic Hypotension: JACC State-of-the-Art Review. J Am Coll Cardiol. 2018 Sep 11;72(11):1294-1309. doi: 10.1016/j.jacc.2018.05.079.
PubMed 30190008Morgan BJ, Crabtree DC, Palta M, Skatrud JB. Combined hypoxia and hypercapnia evokes long-lasting sympathetic activation in humans. J Appl Physiol (1985). 1995 Jul;79(1):205-13. doi: 10.1152/jappl.1995.79.1.205.
PubMed 7559221Freeman R, Wieling W, Axelrod FB, Benditt DG, Benarroch E, Biaggioni I, Cheshire WP, Chelimsky T, Cortelli P, Gibbons CH, Goldstein DS, Hainsworth R, Hilz MJ, Jacob G, Kaufmann H, Jordan J, Lipsitz LA, Levine BD, Low PA, Mathias C, Raj SR, Robertson D, Sandroni P, Schatz I, Schondorff R, Stewart JM, van Dijk JG. Consensus statement on the definition of orthostatic hypotension, neurally mediated syncope and the postural tachycardia syndrome. Clin Auton Res. 2011 Apr;21(2):69-72. doi: 10.1007/s10286-011-0119-5. No abstract available.
PubMed 21431947Shoemaker JK, Vovk A, Cunningham DA. Peripheral chemoreceptor contributions to sympathetic and cardiovascular responses during hypercapnia. Can J Physiol Pharmacol. 2002 Dec;80(12):1136-44. doi: 10.1139/y02-148.
PubMed 12564639Fuglsang CH, Johansen T, Kaila K, Kasch H, Bach FW. Treatment of acute migraine by a partial rebreathing device: A randomized controlled pilot study. Cephalalgia. 2018 Sep;38(10):1632-1643. doi: 10.1177/0333102418797285. Epub 2018 Aug 22.
PubMed 30134739
Study at a glance
From the registry record, last updated by the sponsor on 5 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- CO2 Rebreathing to Increase Blood Pressure in Neurogenic Orthostatic Hypotension: A Proof-of-Concept Pilot Study
- ClinicalTrials.gov ID
- NCT05908760
- Acronym / sponsor ID
- REB23-0791
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 28 participants (estimated)
- Lead sponsor
- University of CalgaryUniversity, hospital or other
- Study start
- 30 Jul 2024 (actual)
- Primary completion
- 31 Dec 2029 (estimated)
- Study completion
- 31 Dec 2030 (estimated)
- First posted
- 18 Jun 2023 (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.
Neurogenic orthostatic hypotension (nOH) is a chronic condition associated with increased cardiovascular risk and reduced quality of life. On standing, patients with nOH experience a large reduction in blood pressure (BP; at least ≥20/10mmHg, but often much more), which is often accompanied by debilitating symptoms and syncope. A previous study (unpublished) showed that hypercapnia significantly increases standing BP in patients with nOH. Human bodies naturally produce and exhale CO2. Rebreathe devices offer a simple, cost-effective technology to increase arterial CO2. In brief, rebreathe devices work by capturing expired CO2, which is then re-inhaled. The net effect is a transient increase in CO2. A CO2 rebreathing device may offer a novel hemodynamic therapy for patients with nOH.
This is a pilot, proof-of-concept study to evaluate a CO2 rebreather to improve blood pressure and orthostatic tolerance in patients with nOH. The hypothesis is that a rebreather will increase CO2 sufficiently enough to improve BP in patients with nOH.
Male and female patients (n=28) will be asked to complete two randomized 70° head-up tilt (HUT) tests breathing either room air or using a CO2 rebreather. Hemodynamics (BP, heart rate, stroke volume, brain blood flow) and orthostatic symptoms will be assessed throughout. Breath-by-breath data will include O2, CO2, respiration rate and tidal volume.
The primary outcome measure will be the magnitude of the BP response (ΔBP = HUT - Supine) during Room Air vs. Hypercapnia. The primary outcome will be compared between room air and hypercapnia using a paired t-test.
Detailed description
BACKGROUND: Neurogenic orthostatic hypotension (nOH) is a chronic condition associated with increased cardiovascular risk and reduced quality of life. On standing, patients with nOH experience a large reduction in blood pressure (BP; at least ≥20/10mmHg, but often much more), which is often accompanied by debilitating symptoms and syncope. nOH affects the elderly and patients with neurodegenerative diseases (e.g., Parkinson's disease, multiple system atrophy), neuropathies (e.g., diabetes), and neural injury (e.g., spinal cord injury).
In healthy controls, hypercapnia (i.e., high CO2) increases in sympathetic nerve activity and BP. Hypercapnia significantly increases supine and seated BP in patients with nOH, and a previous study (unpublished) showed that hypercapnia significantly increases standing BP in patients with nOH.
Human bodies naturally produce and exhale CO2. Rebreathe devices offer a simple, cost-effective technology to increase arterial CO2. In brief, rebreathe devices work by capturing expired CO2, which is then re-inhaled. The net effect is a transient increase in CO2. A CO2 rebreathing device may offer a novel hemodynamic therapy for patients with nOH.
OBJECTIVE: This is a pilot, proof-of-concept study to evaluate a CO2 rebreather to improve blood pressure and orthostatic tolerance in patients with nOH. The study hypothesis is that a rebreather will increase CO2 sufficiently enough to improve BP in patients with nOH.
METHODS: Male and female patients (n=28) will be recruited from the Calgary Autonomic Investigation and Management Clinic.
STUDY PROCEDURE Informed Consent: The informed consent will be sent by email to the patients in advance. The investigators will give each patient a chance to ask questions about the protocol and have these questions answered to their satisfaction. Written informed consent will be documented prior to engaging in study-related procedures.
Holding Pre-Existing Medications: Participants will be asked to hold their clinical medications on the day of the study testing, if possible, but this will not be mandatory. The investigators will make note of the medications used by each participant at the time of the study.
Study Day: Participants will be instrumented at least 2h post-prandial on an empty bladder. Participants will be asked to abstain from alcohol, caffeine, and exercise for a period of 12 hours prior to testing. Participants will be allowed to drink water on the morning of study. Upon lab arrival, a description of the study will be given and written informed consent will be attained if the individual chooses to participate in the study. A member of the research team will ask participants about current medications and other disorders they many have as part of the study inclusion/exclusion criteria. The investigators will also review all other inclusion/exclusion criteria for the study. All study equipment will be introduced to the participant, and then the investigators will begin to prepare for the study.
Participants will be asked to lie supine on the tilt table during instrumentation. Following instrumentation, the study will begin with a 10-minute baseline in the supine position. During this period, the investigators will track blood pressure, heart rate, brain blood flow velocity, fluid shifts, and respiratory pattern using the following equipment:
- Finger and arm blood pressure cuffs
- Skin electrodes to measure heart rate and fluid shifts
- A Transcranial Doppler (TCD) which will use a band around the head, with an ultrasound-like probe at the left and/or right temple
- Pulse oximeter on the finger to measure oxygen saturation
- Participants will be fitted with a mouthpiece to breathing into. The mouthpiece will be connected to a breathing bag that will capture the CO2 exhaled. The mouthpiece will also be connected to a tube that will measure respiratory rate, respiratory depth, CO2 and O2.
Following instrumentation, participants will complete up to two 70° head-up tilt (HUT) tests while breathing either normal room air or while breathing with the rebreather. Each HUT will last a maximum of 5 minutes, and when participants are not upright, the participants will be in the supine position. Participants will be asked to breathe with the rebreather until the measured CO2 increases between 5-10mmHg. Once CO2 is increased, HUT will begin. Participants will continue to breathe with the rebreather until the end of HUT.
The two HUT tests will be randomized and will consist of:
- HUT with Room Air
- HUT with ETCO2 levels increased 5-10mmHg above normal levels
The primary outcome measure will be the magnitude of the BP response (ΔBP = HUT - Supine) during Room Air vs. Hypercapnia. The primary outcome will be compared between room air and hypercapnia using a paired t-test.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Male and female NOH patients (n=28) will be recruited from the Calgary Autonomic Clinic. Participants will complete the following two randomized head-up tilt tests (HUT): * Room Air: Participants will breathe room air while supine and during a 5-min HUT test * CO2 rebreathing: Participants will breathe with the rebreather in the supine position until CO2 levels increase between 5-10mmHg. Once CO2 levels are increased, participants will be tilted upright, and will continue to breathe with the rebreather during a 5-min HUT test
| Arm | Type | Receives |
|---|---|---|
| CO2 Rebreathing | Experimental | Device: CO2 ReHalerParticipants will breathe with the rebreather in the supine position until CO2 levels increase between 5-10mmHg. Once CO2 levels are increased, participants will be tilted upright, and will continue to breathe with the rebreather during a 5-min HUT test |
| Room Air | No intervention | –Participants will breathe room air in the supine position and during a 5-min HUT test |
Who may qualify
- Ages
- 18 to 100 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Age ≥18 years
- Male and Female
- Physician diagnosis of Neurogenic Orthostatic Hypotension
- Non-smokers.
- Able and willing to provide informed consent.
Key exclusion criteria (5 listed)
- Medical therapies or medications which could interfere with testing of autonomic function
- Pregnant or breast-feeding females
- Subjects with chronic heart failure or severe pulmonary disease who are unable to climb one flight of stairs due to shortness of breath.
- Presence of failure of other organ systems or systemic illness that can affect autonomic function or the participant's ability to cooperate. These include dementia, alcohol and/or drug abuse, cerebrovascular disease, kidney or liver disease, surgical procedures where the nerves of the sympathetic nervous system have been cut.
- Other factors which in the investigator's opinion would prevent the participant from completing the protocol, including poor compliance during previous studies.
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 |
|---|---|---|
| CO2 ReHalerThe ReHaler captures expired CO2, which is then re-inhaled. The net effect is a transient increase in CO2. | Device | CO2 Rebreathing |
Primary outcome
Δ Blood Pressure (BP)
Time frame: The ΔBP (HUT-Supine) calculated as the average BP in the final two minutes of supine baseline and the average BP between minute 3 and 5 of HUT will be compared between room air and CO2 rebreathe
Magnitude of ΔBP (HUT-Supine) breathing room air vs CO2 rebreathe
2 secondary outcomes
Δ Vanderbilt Orthostatic Symptom Score [Range: 0 (absent) to 10 (worst)]
Time frame: The Δ Vanderbilt Orthostatic Symptom Score (symptoms at the 5th minute of HUT - symptoms at the 5th minute of supine rest) will be compared between room air vs CO2 rebreathe
Δ Cerebral Blood Flow Velocity (CBFv)
Time frame: The ΔCBFv (HUT-Supine) calculated as the average CBFv in the final two minutes of supine baseline and the average CBFv between minute 3 and 5 of HUT will be compared between room air and CO2 rebreathe
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 5 May 2026.
- Background: PubMed 30190008Freeman R, Abuzinadah AR, Gibbons C, Jones P, Miglis MG, Sinn DI. Orthostatic Hypotension: JACC State-of-the-Art Review. J Am Coll Cardiol. 2018 Sep 11;72(11):1294-1309. doi: 10.1016/j.jacc.2018.05.079.
- Background: PubMed 7559221Morgan BJ, Crabtree DC, Palta M, Skatrud JB. Combined hypoxia and hypercapnia evokes long-lasting sympathetic activation in humans. J Appl Physiol (1985). 1995 Jul;79(1):205-13. doi: 10.1152/jappl.1995.79.1.205.
- Background: PubMed 21431947Freeman R, Wieling W, Axelrod FB, Benditt DG, Benarroch E, Biaggioni I, Cheshire WP, Chelimsky T, Cortelli P, Gibbons CH, Goldstein DS, Hainsworth R, Hilz MJ, Jacob G, Kaufmann H, Jordan J, Lipsitz LA, Levine BD, Low PA, Mathias C, Raj SR, Robertson D, Sandroni P, Schatz I, Schondorff R, Stewart JM, van Dijk JG. Consensus statement on the definition of orthostatic hypotension, neurally mediated syncope and the postural tachycardia syndrome. Clin Auton Res. 2011 Apr;21(2):69-72. doi: 10.1007/s10286-011-0119-5. No abstract available.
- Background: PubMed 12564639Shoemaker JK, Vovk A, Cunningham DA. Peripheral chemoreceptor contributions to sympathetic and cardiovascular responses during hypercapnia. Can J Physiol Pharmacol. 2002 Dec;80(12):1136-44. doi: 10.1139/y02-148.
- Background: PubMed 30134739Fuglsang CH, Johansen T, Kaila K, Kasch H, Bach FW. Treatment of acute migraine by a partial rebreathing device: A randomized controlled pilot study. Cephalalgia. 2018 Sep;38(10):1632-1643. doi: 10.1177/0333102418797285. Epub 2018 Aug 22.
- Individual participant dataSharing planned: No
Related trials for Neurogenic Orthostatic Hypotension
Active, not recruitingPhase 2
A Study in Subjects With Neurogenic Orthostatic Hypotension
Neurogenic Orthostatic Hypotension
Not yet recruiting
Spinal Cord Stimulation for Neurogenic Orthostatic Hypotension
Neurogenic Orthostatic Hypotension
Not yet recruitingObservational study
Artificial Intelligence-based Parkinson's Disease Risk Assessment (AI-PRA) Study
Parkinson Disease (PD), REM Sleep Behavior Disorder (iRBD)
Recruiting
Use of Accelerometer for Quantification of Neurogenic Orthostatic Hypotension Symptoms
Orthostatic; Hypotension, Neurogenic, Autonomic Failure
RecruitingObservational study
Natural History Study of Synucleinopathies
Patients With Synucleinopathies, Neurogenic Orthostatic Hypotension
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.
Satish R Raj, MD principal investigator
University of Calgary
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing CO2 ReHaler in people with Neurogenic Orthostatic Hypotension and Autonomic Failure, 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 6 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 5 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. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
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?
Contact Jacquie Baker, PhD (4032103819, autonomic.research@ucalgary.ca), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Δ Blood Pressure (BP) (time frame: The ΔBP (HUT-Supine) calculated as the average BP in the final two minutes of supine baseline and the average BP between minute 3 and 5 of HUT will be compared between room air and CO2 rebreathe). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05908760, which also lists 5 linked publications.
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 5 May 2026.