Hyperbaric Oxygen TherapyNCT06619717
Optimal Number of Hyperbaric Oxygen Treatments for Carbon Monoxide Poisoning
A study testing Hyperbaric Oxygen Therapy in people with Hyperbaric Oxygen Therapy and Carbon Monoxide Poisoning, run by University of Alberta at 1 site in Canada.
Trial summary
The optimal treatment strategy with hyperbaric oxygen therapy has been the subject of some debate over the past 3 decades. Initial landmark studies showed a decrease in the incidence of DNS with a single treatment and also with three treatments over the course of 24 hours. Read more about this study
- Who is it for?
- Ages 17 years and older
- Conditions the study is for
- Hyperbaric Oxygen Therapy, Carbon Monoxide Poisoning
- What is being tested?
- Hyperbaric Oxygen Therapy
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 2 participants
- Where
- 1 siteCanada
- Study dates
- 24 Jan 2025to 10 Feb 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
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 17 years and older
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Who may be able to join
- All adult (over 17 years old) patients referred to a Hyperbaric Unit for acute carbon monoxide poisoning.
Who cannot join
- Obtunded
- Mechanically ventilated
- Pregnant
- Incarcerated
- Cognitively impaired (acutely or chronically)
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Optimizing Hyperbaric Oxygen Treatments for Acute Carbon Monoxide Poisoning: An Open-label Randomized Study.
The optimal treatment strategy with hyperbaric oxygen therapy has been the subject of some debate over the past 3 decades. Initial landmark studies showed a decrease in the incidence of DNS with a single treatment and also with three treatments over the course of 24 hours. These two strategies have continued to be used widely without further evidence comparing them in a direct fashion. Retrospective publications in the years since have been largely conflicting about the benefit of additional hyperbaric treatments. The investigators would seek to randomize patients with carbon monoxide poisoning to receive with 1 or 3 treatments with hyperbaric oxygen and measure their neurologic outcomes.
Read the detailed description
HBO is a niche treatment modality, especially in Canada. There are few sites which offer this care, and as such, treatment often carries significant logistical challenges. Since 2021, the HBO unit at the Misericordia hospital has averaged 49 patients per year being treated for CO poisoning. This HBO unit provides coverage to patients within Alberta, Saskatchewan, Manitoba, Yukon, and Northwest Territories. Due to the significant barriers to treatment, including the high cost to the public system, it is important to clearly understand how to best treat these patients.
Purpose:
The aim of this study is to assess whether a single treatment session of hyperbaric oxygen is non-inferior to three treatments for patients with acute carbon monoxide poisoning.
- Being tested
- Hyperbaric Oxygen Therapy
- Medical subject headings
- Carbon Monoxide Poisoning
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Hyperbaric Oxygen TherapyProcedure or surgery
Three treatments with hyperbaric oxygen therapy. The exact parameters of each dive will be left to individual clinicians. Commonly used treatments would be:
Weaver protocol, or similar (i.e. 100% oxygen at 3 atmospheres for 90 minutes with two 10-minute air breaks every 30 minutes. Repeat this every 8 hours until 3 treatments are complete.)
Hyperbaric Oxygen TherapyProcedure or surgery
Single treatment with hyperbaric oxygen. Exact parameters left to treating physician but commonly: 100% oxygen at 2.8 atmospheres for 30 minutes followed by a 10-minute air break, then 100% oxygen at 2 atmospheres for 60 minutes with one 10-minute air break after 30 minutes
| Study group | Role | What they receive |
|---|---|---|
| Single HBO treatment | Active comparator | The exact parameters of each dive will be left to individual clinicians. Commonly used treatments would be:
1 treatment: 100% oxygen at 2.8 atmospheres for 30 minutes followed by a 10-minute air break, then 100% oxygen at 2 atmospheres for 60 minutes with one 10-minute air break after 30 minutes Receives: Procedure: Hyperbaric Oxygen Therapy |
| Three HBO treatments | Experimental | The exact parameters of each dive will be left to individual clinicians. Commonly used treatments would be:
3 treatments: Weaver protocol or similar variation (i.e. 100% oxygen at 3 atmospheres for 90 minutes with two 10-minute air breaks every 30 minutes. This will be repeated every 8 hours until 3 treatments are complete.) Receives: Procedure: Hyperbaric Oxygen Therapy |
What is being measured
The primary outcome is the main question the study is designed to answer.
Proportion of patients experiencing delayed neurologic sequalae
DNS includes a spectrum of symptoms such as depression, anxiety, memory issues, ataxia, behavioral changes, decreased cognitive function. For CO-poisoned patients who do not succumb to the direct effects of hypoxia, DNS is one of the primary causes of long-term morbidity.
The presence of delayed neurologic sequelae as measured by a series of standardized tests. These tests will include digit span (Attention), the Boston Naming Test 15 (aphasia), general orientation and delayed recall (memory), and clock drawing (visuospatial). DNS will be considered present if a patient scores ≥2 SD below the standardized T scores for any neuropsychological test, if they score ≥1 SD below the standardized T scores for 2 or more tests, or if they score ≥1 SD below the standardized T score for any test and self-report poor memory/concentration/attention.
Measured: 6 weeks and 6 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 Oct 2024
- Study start24 Jan 2025
- Primary completion10 Feb 2026
- Study completion10 Feb 2026
Why it stopped: Futility of enrollment.
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Hyperbaric Oxygen TherapyStudies of the same condition, open and under way.
- More trials run by University of AlbertaThe 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
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 2 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Alberta
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Brian Rowe, MD, MSc, CCFP (EM), FCCP, Study director, Professor in the Department of Emergency Medicine, Faculty of Medicine & Dentistry, College of Health Sciences, at the University of Alberta
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06619717
- Sponsor's protocol ID
- Pro00146529
- Status last verified
- Mar 2026
- First submitted
- 26 Sep 2024
- Last updated
- 13 Mar 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 13 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Optimizing Hyperbaric Oxygen Treatments for Acute Carbon Monoxide Poisoning: An Open-label Randomized Study.
- ClinicalTrials.gov ID
- NCT06619717
- Acronym / sponsor ID
- Pro00146529
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: Futility of enrollment.
- Enrolment
- 2 participants (actual)
- Lead sponsor
- University of AlbertaUniversity, hospital or other
- Study start
- 24 Jan 2025 (actual)
- Primary completion
- 10 Feb 2026 (actual)
- Study completion
- 10 Feb 2026 (actual)
- First posted
- 1 Oct 2024 (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.
The optimal treatment strategy with hyperbaric oxygen therapy has been the subject of some debate over the past 3 decades. Initial landmark studies showed a decrease in the incidence of DNS with a single treatment and also with three treatments over the course of 24 hours. These two strategies have continued to be used widely without further evidence comparing them in a direct fashion. Retrospective publications in the years since have been largely conflicting about the benefit of additional hyperbaric treatments. The investigators would seek to randomize patients with carbon monoxide poisoning to receive with 1 or 3 treatments with hyperbaric oxygen and measure their neurologic outcomes.
Detailed description
HBO is a niche treatment modality, especially in Canada. There are few sites which offer this care, and as such, treatment often carries significant logistical challenges. Since 2021, the HBO unit at the Misericordia hospital has averaged 49 patients per year being treated for CO poisoning. This HBO unit provides coverage to patients within Alberta, Saskatchewan, Manitoba, Yukon, and Northwest Territories. Due to the significant barriers to treatment, including the high cost to the public system, it is important to clearly understand how to best treat these patients.
Purpose:
The aim of this study is to assess whether a single treatment session of hyperbaric oxygen is non-inferior to three treatments for patients with acute carbon monoxide poisoning.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Single HBO treatment | Active comparator | Procedure: Hyperbaric Oxygen TherapyThe exact parameters of each dive will be left to individual clinicians. Commonly used treatments would be: 1 treatment: 100% oxygen at 2.8 atmospheres for 30 minutes followed by a 10-minute air break, then 100% oxygen at 2 atmospheres for 60 minutes with one 10-minute air break after 30 minutes |
| Three HBO treatments | Experimental | Procedure: Hyperbaric Oxygen TherapyThe exact parameters of each dive will be left to individual clinicians. Commonly used treatments would be: 3 treatments: Weaver protocol or similar variation (i.e. 100% oxygen at 3 atmospheres for 90 minutes with two 10-minute air breaks every 30 minutes. This will be repeated every 8 hours until 3 treatments are complete.) |
Who may qualify
- Ages
- 17 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (1 listed)
- All adult (over 17 years old) patients referred to a Hyperbaric Unit for acute carbon monoxide poisoning.
Key exclusion criteria (5 listed)
- Obtunded
- Mechanically ventilated
- Pregnant
- Incarcerated
- Cognitively impaired (acutely or chronically)
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 |
|---|---|---|
| Hyperbaric Oxygen TherapyThree treatments with hyperbaric oxygen therapy. The exact parameters of each dive will be left to individual clinicians. Commonly used treatments would be: Weaver protocol, or similar (i.e. 100% oxygen at 3 atmospheres for 90 minutes with two 10-minute air breaks every 30 minutes. Repeat this every 8 hours until 3 treatments are complete.) | Procedure or surgery | Three HBO treatments |
| Hyperbaric Oxygen TherapySingle treatment with hyperbaric oxygen. Exact parameters left to treating physician but commonly: 100% oxygen at 2.8 atmospheres for 30 minutes followed by a 10-minute air break, then 100% oxygen at 2 atmospheres for 60 minutes with one 10-minute air break after 30 minutes | Procedure or surgery | Single HBO treatment |
Primary outcome
Proportion of patients experiencing delayed neurologic sequalae
Time frame: 6 weeks and 6 months
DNS includes a spectrum of symptoms such as depression, anxiety, memory issues, ataxia, behavioral changes, decreased cognitive function. For CO-poisoned patients who do not succumb to the direct effects of hypoxia, DNS is one of the primary causes of long-term morbidity. The presence of delayed neurologic sequelae as measured by a series of standardized tests. These tests will include digit span (Attention), the Boston Naming Test 15 (aphasia), general orientation and delayed recall (memory), and clock drawing (visuospatial). DNS will be considered present if a patient scores ≥2 SD below the standardized T scores for any neuropsychological test, if they score ≥1 SD below the standardized T scores for 2 or more tests, or if they score ≥1 SD below the standardized T score for any test and self-report poor memory/concentration/attention.
Results and safety
The study was stopped early (reason given: Futility of enrollment.). Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 13 Mar 2026.
- Individual participant dataSharing planned: No
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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. This study is not recruiting at the moment.
Brian Rowe, MD, MSc, CCFP (EM), FCCP study director
Professor in the Department of Emergency Medicine, Faculty of Medicine & Dentistry, College of Health Sciences, at the University of Alberta
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Hyperbaric Oxygen Therapy in people with Hyperbaric Oxygen Therapy and Carbon Monoxide Poisoning, run by University of Alberta 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 1 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: stopped early, as of the sponsor's last update on 13 Mar 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?
The study was stopped early (reason given: Futility of enrollment.). Results are not available in the source record.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Proportion of patients experiencing delayed neurologic sequalae (time frame: 6 weeks and 6 months). 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 13 Mar 2026.