Effect of Hydrogen Gas on Hyperbaric Oxygen Toxicity (NCT07263399) | Clinical Trial Compass
Not Yet RecruitingNot Applicable
Effect of Hydrogen Gas on Hyperbaric Oxygen Toxicity
Sweden32 participantsStarted 2026-01
Plain-language summary
The goal of this trial is to investigate whether adding a small fraction of hydrogen gas to an oxygen-enriched breathing mixture can reduce pulmonary oxygen toxicity (POT) in healthy and active divers from the Swedish Armed Forces. The main questions it aims to answer are:
* Does hydrogen gas reduce oxidative stress and changes in pulmonary function associated with prolonged hyperbaric oxygen exposure?
* What are the underlying pathophysiological mechanisms of pulmonary oxygen toxicity?
Researchers will compare oxygen-enriched breathing gas with 1-2% hydrogen to oxygen-enriched gas with 1-2% nitrogen (control) to see if hydrogen provides protective effects against POT during hyperbaric exposure.
Participants will:
* Complete two hyperbaric exposure sessions (hydrogen vs. nitrogen), each lasting 240 minutes at 1.75 ATA
* Undergo pulmonary function tests and sampling of blod and urin before and after each session
* Serve as their own controls in a double-blind, randomized, crossover study design
Who can participate
Age range
20 Years – 64 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion Criteria:
* Military divers actively serving, aged 20-64 years
* Meeting the Swedish Armed Forces physical standards for diving
Exclusion Criteria:
* Ongoing infection or illness that may impact pulmonary function
* Use of alcohol or smoking cigarettes within 48 hours
* Diving with any breathing gas within 48 hours
* Diving with oxygen-enriched gas (100% O₂) within 2 weeks
* Use of medications that could affect oxidative stress, lung function, or neurological status
* Medical history of serious diving-related injuries or long-term complications
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
Change in Vital Capacity (ΔVC)
Timeframe: Pre-exposure, 30-120 minutes post-exposure, and 24-36 hours post-exposure.