HyperbaricPhase 2/3NCT02468752
Reduction of Venous Emboli Load After Breathing Normobaric Oxygen Compared to Air
A Phase 2/3 study testing Oxygen and Air in people with Hyperbaric and Diving Medicine, run by Göteborg University at 2 sites in Sweden.
Trial summary
Primary objective: Assessment of venous gas emboli load post diving when breathing normobaric oxygen compared to air. Secondary objective: Assessment of fluid markers of central nervous system injury in blood post diving Assessment of fluid markers of inflammation and endothelial dysfunction in blood post diving… Read more about this study
- Who is it for?
- Ages 18 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Hyperbaric, Diving Medicine, Decompression Sickness
- What is being tested?
- Oxygen and Air
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 48 participants
- Where
- 2 sitesSweden
- Study dates
- May 2015to Apr 2019
- Phase
- Phase 2/3
- 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 18 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Professional diver
- Fit to dive according to Swedish Navy standards
Who cannot join
- NONE
Trial locations and contacts
2 sites in 1 country.
Sweden2 sites
Sahlgrenska University Hospital
Gothenburg, S-416 85
Kungliga Tekniska Högskolan
Stockholm, S-100 44
About this study
Official title: Mängden kvävgasbubblor i Blodet Efter Dykning Vid Syrgasandning jämfört Med Luftandning
Primary objective:
- Assessment of venous gas emboli load post diving when breathing normobaric oxygen compared to air.
Secondary objective:
- Assessment of fluid markers of central nervous system injury in blood post diving
- Assessment of fluid markers of inflammation and endothelial dysfunction in blood post diving
Tertiary objective:
- Assessment of DCS frequency
Read the detailed description
This is a prospective, double blinded, randomized, cross-over study in Sweden. The study was performed in two different sets, each containing standardized dives in a wet hyperbaric chamber. The dives included movement on depth.
In each study set 16-32 professional divers performed no-decompression dives to a depth of 42 metres of seawater (msw). The gas used during the dives was compressed air.
After surfacing the divers breathed either normobaric oxygen or normobaric air on a demand mask. Timing of oxygen/air-breathing differed between study sets. The content of breathing gas was unknown to both divers and examining personnel.
Immediately post dive the divers were assessed using either transthoracic doppler ultrasound (TTD) or transthoracic 2-D ultrasound (TTE) to determine VGE load, time to VGE detection and VGE duration.
Signs of DCS were actively sought.
TTD measurements were done every five minutes during the first 30 minutes, thereafter every 15 minutes during 90 minutes.
TTE was performed every 30 minutes, using an apical 4-chamber view.
Blood samples were obtained pre-dive, 30-45 minutes post-dive and 120 minutes post-dive.
Set 1: 16 divers, divided into two equal groups (A and B). Dive to 42 msw during 10 min with a safety stop at five msw during three min. Immediately post dive breathing of oxygen (group A) or air (group B) during 30 min. VGE load, time to VGE detection and VGE duration is recorded. Blood samples were obtained pre-dive and 30 and 120 minutes post-dive. After 48 hours, the dives were repeated with switched gases between the groups.
Set 2: 32 divers, divided into two equal groups (A and B). Dive to 42 msw during 10 min with a safety stop at five msw during three min. Fifteen minutes post dive breathing of oxygen (group A) or air (group B) during 30 min. VGE load, time to VGE detection and VGE duration is recorded. Blood samples were obtained pre-dive and 45 and 120 minutes post-dive, from the first 16 divers. After 48 hours, the dives were repeated with switched gases between the groups.
Two further planned sets with repeated diving and shorter duration of oxygen/air-breathing were never carried through.
AE including SAE will be recorded during the study. DCS may be considered either an AE or SAE depending on severity. Ongoing AE and SAE will be followed up.
- Conditions
- Hyperbaric, Diving Medicine, Decompression Sickness, Central Nervous Injury, Inflammation, Endothelial Dysfunction
- Being tested
- Oxygen, Air
- Medical subject headings
- Decompression Sickness, Inflammation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
OxygenDrug
AirOther
| Study group | Role | What they receive |
|---|---|---|
| Air | Sham comparator | Normobaric air breathing Receives: Other: Air |
| Oxygen | Experimental | Normobaric oxygen breathing Receives: Drug: Oxygen |
What is being measured
The primary outcome is the main question the study is designed to answer.
Venous gas emboli
Kisman-Masurel grading
Measured: 120 minutes
Secondary outcomes (3)
Inflammatory activity and endothelial dysfunction
E.g. VCAM-1, ICAM-1
Measured: 120 minutes/ 48 hours
Decompression sickness
Clinical diagnosis
Measured: 24 hours
Markers of central nervous system injury
E.g. GFAP, Tau, NfL, UCHL-1
Measured: 120 minutes/ 48 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 Jun 2015 (estimated)
- Study startMay 2015
- Primary completionApr 2019
- Study completionApr 2019
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HyperbaricStudies of the same condition, open and under way.
- More trials run by Göteborg UniversityThe 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 2/3
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind
- Who is masked
- Participant, Care provider, Investigator
- Enrolment
- 48 participants (actual)
Sponsor and investigators
- Lead sponsor
- Göteborg University
- Sponsor type
- University, hospital or other
- Collaborators
- Swedish Armed Forces Diving and Naval Medicine Centre, KTH Royal Institute of Technology, Sahlgrenska University Hospital
- Responsible party
- Principal investigator, Nicklas Oscarsson, Göteborg University
- Investigators
- Mikael Gennser, PhD, Principal investigator, Kungliga Tekniska Högskolan, Stockholm, Sweden
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02468752
- Sponsor's protocol ID
- DYK 14-16
- Status last verified
- May 2022
- First submitted
- 3 Jun 2015
- Last updated
- 27 May 2022
- Results posted
- No
- Data monitoring committee
- 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 27 May 2022. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Mängden kvävgasbubblor i Blodet Efter Dykning Vid Syrgasandning jämfört Med Luftandning
- ClinicalTrials.gov ID
- NCT02468752
- Acronym / sponsor ID
- DYK 14-16
- Conditions
- Hyperbaric, Diving Medicine, Decompression Sickness, Central Nervous Injury, Inflammation, Endothelial Dysfunction
- Phase
- Phase 2/3
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 48 participants (actual)
- Lead sponsor
- Göteborg UniversityUniversity, hospital or other
- Collaborators
- Swedish Armed Forces Diving and Naval Medicine Centre, KTH Royal Institute of Technology, Sahlgrenska University Hospital
- Study start
- May 2015 (actual)
- Primary completion
- Apr 2019 (actual)
- Study completion
- Apr 2019 (actual)
- First posted
- 11 Jun 2015 (estimated)
- 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.
Primary objective:
- Assessment of venous gas emboli load post diving when breathing normobaric oxygen compared to air.
Secondary objective:
- Assessment of fluid markers of central nervous system injury in blood post diving
- Assessment of fluid markers of inflammation and endothelial dysfunction in blood post diving
Tertiary objective:
- Assessment of DCS frequency
Detailed description
This is a prospective, double blinded, randomized, cross-over study in Sweden. The study was performed in two different sets, each containing standardized dives in a wet hyperbaric chamber. The dives included movement on depth.
In each study set 16-32 professional divers performed no-decompression dives to a depth of 42 metres of seawater (msw). The gas used during the dives was compressed air.
After surfacing the divers breathed either normobaric oxygen or normobaric air on a demand mask. Timing of oxygen/air-breathing differed between study sets. The content of breathing gas was unknown to both divers and examining personnel.
Immediately post dive the divers were assessed using either transthoracic doppler ultrasound (TTD) or transthoracic 2-D ultrasound (TTE) to determine VGE load, time to VGE detection and VGE duration.
Signs of DCS were actively sought.
TTD measurements were done every five minutes during the first 30 minutes, thereafter every 15 minutes during 90 minutes.
TTE was performed every 30 minutes, using an apical 4-chamber view.
Blood samples were obtained pre-dive, 30-45 minutes post-dive and 120 minutes post-dive.
Set 1: 16 divers, divided into two equal groups (A and B). Dive to 42 msw during 10 min with a safety stop at five msw during three min. Immediately post dive breathing of oxygen (group A) or air (group B) during 30 min. VGE load, time to VGE detection and VGE duration is recorded. Blood samples were obtained pre-dive and 30 and 120 minutes post-dive. After 48 hours, the dives were repeated with switched gases between the groups.
Set 2: 32 divers, divided into two equal groups (A and B). Dive to 42 msw during 10 min with a safety stop at five msw during three min. Fifteen minutes post dive breathing of oxygen (group A) or air (group B) during 30 min. VGE load, time to VGE detection and VGE duration is recorded. Blood samples were obtained pre-dive and 45 and 120 minutes post-dive, from the first 16 divers. After 48 hours, the dives were repeated with switched gases between the groups.
Two further planned sets with repeated diving and shorter duration of oxygen/air-breathing were never carried through.
AE including SAE will be recorded during the study. DCS may be considered either an AE or SAE depending on severity. Ongoing AE and SAE will be followed up.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind (participant, care provider, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Air | Sham comparator | Other: AirNormobaric air breathing |
| Oxygen | Experimental | Drug: OxygenNormobaric oxygen breathing |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- Professional diver
- Fit to dive according to Swedish Navy standards
Key exclusion criteria (1 listed)
- NONE
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 |
|---|---|---|
| Oxygen | Drug | Oxygen |
| Air | Other | Air |
Primary outcome
Venous gas emboli
Time frame: 120 minutes
Kisman-Masurel grading
3 secondary outcomes
Inflammatory activity and endothelial dysfunction
Time frame: 120 minutes/ 48 hours
Decompression sickness
Time frame: 24 hours
Markers of central nervous system injury
Time frame: 120 minutes/ 48 hours
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 27 May 2022.
- 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.
Mikael Gennser, PhD principal investigator
Kungliga Tekniska Högskolan, Stockholm, Sweden
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2/3 study testing Oxygen and Air in people with Hyperbaric and Diving Medicine, run by Göteborg University at 2 sites in Sweden.
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 2 inclusion and 1 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: finished, as of the sponsor's last update on 27 May 2022. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Sweden. 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 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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?
Venous gas emboli (time frame: 120 minutes). 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 27 May 2022; AzTrials last refreshed its copy on 1 Nov 2026.