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Factors Affecting Oxygen Toxicity

N/A
Recruiting
Led By Derek B Covington, MD
Research Sponsored by Duke University
Eligibility Criteria Checklist
Specific guidelines that determine who can or cannot participate in a clinical trial
Must have
Equal numbers of male and female
Aged 18-45 years
Timeline
Screening 3 weeks
Treatment Varies
Follow Up baseline and after intervention/arm, which averages 3 months
Awards & highlights

Summary

This trial wants to understand how oxygen toxicity affects scuba divers. They want to find out how different factors like training of respiratory muscles, environmental conditions, and immersion in water affect the risk of oxygen toxicity

Who is the study for?
This trial is for non-smoking men and women aged 18-45 who are in good health with a specific level of cardiovascular fitness (VO2 peak). It's designed to understand oxygen toxicity in scuba divers, focusing on how respiratory training, environmental factors like sleep deprivation and CO2 exposure, affect the risk.
What is being tested?
The study tests the effects of carbon dioxide, caffeine, sleep deprivation, and methylphenidate on oxygen toxicity. Participants will undergo respiratory muscle training and exercise tests both dry and underwater to measure changes in performance, lung function, brain blood flow, and gene expression.
What are the potential side effects?
Potential side effects may include discomfort from respiratory exercises or cycle ergometer use. Exposure to high oxygen levels can lead to seizures or lung irritation. Caffeine might cause jitteriness or heart palpitations; methylphenidate could have similar stimulant effects.

Eligibility Criteria

Inclusion Criteria

You may be eligible if you check “Yes” for the criteria below
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My gender has been considered for the study's balance.
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I am between 18 and 45 years old.
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My peak oxygen intake meets the required level.

Timeline

Screening ~ 3 weeks
Treatment ~ Varies
Follow Up ~baseline and after intervention/arm, which averages 3 months
This trial's timeline: 3 weeks for screening, Varies for treatment, and baseline and after intervention/arm, which averages 3 months for reporting.

Treatment Details

Study Objectives

Study objectives can provide a clearer picture of what you can expect from a treatment.
Secondary study objectives
Integrated diaphragmatic function (IDF) composite score

Trial Design

4Treatment groups
Experimental Treatment
Active Control
Group I: MethylphenidateExperimental Treatment1 Intervention
Effect of caffeine and methylphenidate on HCVR and arterial PCO2 during submersed rest and exercise at 98 fsw. Twenty subjects will be similarly sleep-deprived, tested as above and then re-tested tested following oral administration of administration of either oral caffeine (N=10) or methylphenidate (N=10). Pre-dive caffeine will be administered 500 mg orally \[59\]. Pre-dive methylphenidate will be administered as a single dose of 5 mg \[60\]. The order of drug administration vs. control will be randomized. Measurements at 98 fsw will be obtained at rest and during 10 minutes of moderate exercise in thermoneutral (29-30°C) water. fNIRS will be used to assess cerebral oxygenation and regional blood volume.
Group II: Carbon Dioxide ExposureExperimental Treatment1 Intervention
Effect of simulated chronic CO2 exposure on HCVR and arterial PCO2 during submersed rest and exercise at 98 fsw. Ten subjects will be studied before and after induction of metabolic alkalosis as described above with daily oral administration of sodium bicarbonate. Oral bicarbonate to simulate hypercapnia exposure will seek to increase serum bicarbonate to 30 mM/L via daily oral intake of 6 teaspoons of NaHCO3 for five days. Subsequently, blood will be drawn and intake adjusted as necessary \[61\]. The order of alkalization vs. control will be randomized. Measurements at 98 fsw will be obtained at rest and during 10 minutes of moderate exercise in thermoneutral (29-30°C) water.
Group III: CaffeineExperimental Treatment1 Intervention
Effect of caffeine and methylphenidate on HCVR and arterial PCO2 during submersed rest and exercise at 98 fsw. Twenty subjects will be similarly sleep-deprived, tested as above and then re-tested tested following oral administration of administration of either oral caffeine (N=10) or methylphenidate (N=10). Pre-dive caffeine will be administered 500 mg orally \[59\]. Pre-dive methylphenidate will be administered as a single dose of 5 mg \[60\]. The order of drug administration vs. control will be randomized. Measurements at 98 fsw will be obtained at rest and during 10 minutes of moderate exercise in thermoneutral (29-30°C) water. fNIRS will be used to assess cerebral oxygenation and regional blood volume.
Group IV: Sleep DeprivationActive Control1 Intervention
Effect of sleep deprivation on HCVR and arterial PCO2 during submersed rest and exercise at 98 fsw. Ten subjects will be tested before and after 24 hours of sleep deprivation. The order of sleep deprivation vs. control will be randomized. Measurements at 98 fsw will be obtained at rest and during 10 minutes of moderate exercise in thermoneutral (29-30°C) water.
Treatment
First Studied
Drug Approval Stage
How many patients have taken this drug
Caffeine
2014
Completed Phase 3
~2980
Carbon Dioxide
2013
Completed Phase 2
~500
Methylphenidate
2014
Completed Phase 4
~431850

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Who is running the clinical trial?

Duke UniversityLead Sponsor
2,424 Previous Clinical Trials
3,066,022 Total Patients Enrolled
13 Trials studying Seizures
36,237 Patients Enrolled for Seizures
Derek B Covington, MDPrincipal InvestigatorDuke University
~39 spots leftby Mar 2026
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