Respiratory MusclesNCT04679402
Diaphragm Function and Diver Endurance
A study testing Carbon monoxide 200 ppm in air in people with Respiratory Muscles, run by Duke University at 1 site in United States.
Trial summary
This project will test the following hypotheses: 1. Training of the inspiratory muscles increases underwater endurance and reduces hypercapnia in divers. 2. Inspiratory muscle training while breathing low concentration carbon monoxide (200 ppm) for 30 minutes daily improves diaphragm performance to a greater degree… Read more about this study
- Who is it for?
- Ages 18 to 45 yearsHealthy volunteers can take part
- Conditions the study is for
- Respiratory Muscles
- What is being tested?
- Carbon monoxide 200 ppm in air
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 45 participants
- Where
- 1 siteUnited States
- Study dates
- 14 Apr 2022to 30 Apr 2024
- 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 18 to 45 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Normal volunteers
- Non-smokers
- Range of hypercapnic ventilatory responses
- VO2peak ≥35 mL.kg-1.min-1 (males)
- ≥30 mL.kg-1.min-1 (females)
Who cannot join
- Pregnancy
- Cardiorespiratory disease, including hypertension
- Neuromuscular disease
- Anemia
- Hemoglobinopathy, including sickle cell disease and trait
Trial locations and contacts
1 site in 1 country.
United States1 site
Duke University Medical Center
Durham, North Carolina, 27710
About this study
This project will test the following hypotheses:
- Training of the inspiratory muscles increases underwater endurance and reduces hypercapnia in divers.
- Inspiratory muscle training while breathing low concentration carbon monoxide (200 ppm) for 30 minutes daily improves diaphragm performance to a greater degree than the same training breathing air.
- Inspiratory muscle training increases hypercapnia ventilatory response (gain) in those individuals with a low gain.
- Variability in oxygen (O2) and carbon dioxide (CO2) permeability of erythrocyte membranes is a determining factor in underwater exercise performance.
Read the detailed description
The aims of this project are to: (1) test a method that could increase personal endurance and reduce excessive rise in blood carbon dioxide during underwater exercise in divers; and (2) understand the mechanisms by which red blood cells transport oxygen and carbon dioxide and their possible effects on exercise capacity. During underwater exercise, personal endurance capacity and elevated blood PCO2 are key parameters that affect a diver's safety and performance. Unlike exercise on dry land, hypercapnia often occurs during dives and can impair cognitive function and predispose the diver to central nervous system (CNS) oxygen toxicity and convulsions underwater. Some people intrinsically have low ventilatory chemosensitivity, and are more likely to develop hypercapnia during a dive. Lack of stamina may also be a mission-critical variable, and both endurance and the ability to control blood carbon dioxide depend on the respiratory muscle (mainly diaphragm) function, for which endurance capacity is related to mitochondrial number. Previous studies from our lab have demonstrated increased mitochondrial biogenesis with training while breathing a low, sub-toxic (200 ppm) level of carbon monoxide. In this study we will test the effect of daily respiratory muscle training with and without added carbon monoxide on respiratory muscle power, diaphragm thickness, respiratory muscle endurance and exercise endurance during a subsequent dive to 50 feet of sea water. Arterial PCO2 and lactic acid levels will be measured during exercise tests before and after training. Transport of O2 and CO2 through erythrocyte cell membranes occurs mostly through channels. Erythrocytes from volunteers in this study will be tested for O2 and CO2 permeability, and to correlate gas transport efficiency with exercise performance and blood PCO2.
- Conditions
- Respiratory Muscles
- Being tested
- Carbon monoxide 200 ppm in air
- Keywords
- Control of breathing, Diaphragm function, Gas channels, Blood gases
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Carbon monoxide 200 ppm in airOther
Low dose carbon monoxide
| Study group | Role | What they receive |
|---|---|---|
| Respiratory Muscle Training Breathing Low Dose Carbon Monoxide | Experimental | Carbon monoxide 200 ppm in air breathing during daily 30 minute inspiratory loading training sessions. Subjects will breathe the experimental gas through a mouthpiece with nose-clip in place. Receives: Other: Carbon monoxide 200 ppm in air |
| Respiratory Muscle Training Breathing Air | Sham comparator | Air breathing during daily 30 minute inspiratory loading training sessions. Subjects will breathe air through a mouthpiece with nose-clip in place. Receives: Other: Carbon monoxide 200 ppm in air |
What is being measured
The primary outcome is the main question the study is designed to answer.
Underwater endurance change
Endurance during continuous underwater exercise at a depth of 50 ft below the surface
Measured: Baseline, 6 weeks
Arterial PCO2 change
Blood gases during and at end of exercise
Measured: Baseline, 6 weeks
Ventilatory chemosensitivity change
Hypercapnic ventilatory response (VE.min-1.mmHg)
Measured: Baseline, 6 weeks
Secondary outcomes (1)
Erythrocyte gas channel analysis
Stopped-flow analysis of O2 offloading from Hb of (a) intact RBCs, (b) Hb in hemolysate
Measured: Baseline
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted22 Dec 2020
- Study start14 Apr 2022
- Primary completion30 Apr 2024
- Study completion30 Apr 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Respiratory MusclesStudies of the same condition, open and under way.
- More trials run by Duke 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 N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Mixed model with repeated measures
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 45 participants (actual)
Sponsor and investigators
- Lead sponsor
- Duke University
- Sponsor type
- University, hospital or other
- Collaborators
- Case Western Reserve University
- Responsible party
- Sponsor
- Investigators
- Richard E Moon, MD, Principal investigator, Duke University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04679402
- Sponsor's protocol ID
- Pro00107090
- Status last verified
- Mar 2024
- First submitted
- 17 Dec 2020
- Last updated
- 13 Jun 2024
- 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 13 Jun 2024. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Diaphragm Function and Diver Endurance
- ClinicalTrials.gov ID
- NCT04679402
- Acronym / sponsor ID
- Pro00107090
- Conditions
- Respiratory Muscles
- Keywords
- Control of breathing, Diaphragm function, Gas channels, Blood gases
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 45 participants (actual)
- Lead sponsor
- Duke UniversityUniversity, hospital or other
- Collaborators
- Case Western Reserve University
- Study start
- 14 Apr 2022 (actual)
- Primary completion
- 30 Apr 2024 (actual)
- Study completion
- 30 Apr 2024 (actual)
- First posted
- 22 Dec 2020 (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.
This project will test the following hypotheses:
- Training of the inspiratory muscles increases underwater endurance and reduces hypercapnia in divers.
- Inspiratory muscle training while breathing low concentration carbon monoxide (200 ppm) for 30 minutes daily improves diaphragm performance to a greater degree than the same training breathing air.
- Inspiratory muscle training increases hypercapnia ventilatory response (gain) in those individuals with a low gain.
- Variability in oxygen (O2) and carbon dioxide (CO2) permeability of erythrocyte membranes is a determining factor in underwater exercise performance.
Detailed description
The aims of this project are to: (1) test a method that could increase personal endurance and reduce excessive rise in blood carbon dioxide during underwater exercise in divers; and (2) understand the mechanisms by which red blood cells transport oxygen and carbon dioxide and their possible effects on exercise capacity. During underwater exercise, personal endurance capacity and elevated blood PCO2 are key parameters that affect a diver's safety and performance. Unlike exercise on dry land, hypercapnia often occurs during dives and can impair cognitive function and predispose the diver to central nervous system (CNS) oxygen toxicity and convulsions underwater. Some people intrinsically have low ventilatory chemosensitivity, and are more likely to develop hypercapnia during a dive. Lack of stamina may also be a mission-critical variable, and both endurance and the ability to control blood carbon dioxide depend on the respiratory muscle (mainly diaphragm) function, for which endurance capacity is related to mitochondrial number. Previous studies from our lab have demonstrated increased mitochondrial biogenesis with training while breathing a low, sub-toxic (200 ppm) level of carbon monoxide. In this study we will test the effect of daily respiratory muscle training with and without added carbon monoxide on respiratory muscle power, diaphragm thickness, respiratory muscle endurance and exercise endurance during a subsequent dive to 50 feet of sea water. Arterial PCO2 and lactic acid levels will be measured during exercise tests before and after training. Transport of O2 and CO2 through erythrocyte cell membranes occurs mostly through channels. Erythrocytes from volunteers in this study will be tested for O2 and CO2 permeability, and to correlate gas transport efficiency with exercise performance and blood PCO2.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- Mixed model with repeated measures
| Arm | Type | Receives |
|---|---|---|
| Respiratory Muscle Training Breathing Low Dose Carbon Monoxide | Experimental | Other: Carbon monoxide 200 ppm in airCarbon monoxide 200 ppm in air breathing during daily 30 minute inspiratory loading training sessions. Subjects will breathe the experimental gas through a mouthpiece with nose-clip in place. |
| Respiratory Muscle Training Breathing Air | Sham comparator | Other: Carbon monoxide 200 ppm in airAir breathing during daily 30 minute inspiratory loading training sessions. Subjects will breathe air through a mouthpiece with nose-clip in place. |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- Normal volunteers
- Non-smokers
- Range of hypercapnic ventilatory responses
- VO2peak ≥35 mL.kg-1.min-1 (males)
- ≥30 mL.kg-1.min-1 (females)
Key exclusion criteria (5 listed)
- Pregnancy
- Cardiorespiratory disease, including hypertension
- Neuromuscular disease
- Anemia
- Hemoglobinopathy, including sickle cell disease and trait
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 |
|---|---|---|
| Carbon monoxide 200 ppm in airLow dose carbon monoxide | Other | Respiratory Muscle Training Breathing Air, Respiratory Muscle Training Breathing Low Dose Carbon Monoxide |
Primary outcome
Underwater endurance change
Time frame: Baseline, 6 weeks
Endurance during continuous underwater exercise at a depth of 50 ft below the surface
Arterial PCO2 change
Time frame: Baseline, 6 weeks
Blood gases during and at end of exercise
Ventilatory chemosensitivity change
Time frame: Baseline, 6 weeks
Hypercapnic ventilatory response (VE.min-1.mmHg)
1 secondary outcome
Erythrocyte gas channel analysis
Time frame: Baseline
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 13 Jun 2024.
- Individual participant dataSharing planned: No
Related trials for Respiratory Muscles
Not yet recruitingObservational study
Intra-Abdominal Pressure, Respiratory Mechanics, and Ventilator Liberation After Emergency Major Laparotomy
Intra-Abdominal Hypertension, Respiratory Mechanics
Not yet recruitingObservational study
Associations of Respiratory Muscle Strength and Trunk Muscle Mechanical Properties With Dynamic Postural Control
Postural Control, Muscle Tonus
RecruitingObservational study
Development of Non-Invasive Prenatal Diagnosis for Single Gene Disorders
Invasive PreNatal Diagnosis in a Context of Family History of Single-gene Disorders, Including, Sickle Cell Disease
Recruiting
Effects of Respiratory Muscle Strengthening and Diaphragmatic Breathing on Shoulder Pain and Disability
Shoulder Pain, Sleep Quality
RecruitingObservational study
CytOSorb TreatMent Of Critically Ill PatientS Registry
Septic Shock, Acute Respiratory Distress Syndrome
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.
Richard E Moon, MD principal investigator
Duke University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Carbon monoxide 200 ppm in air in people with Respiratory Muscles, run by Duke University at 1 site in United States.
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 5 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: finished, as of the sponsor's last update on 13 Jun 2024. 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 United States. 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.
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?
Underwater endurance change (time frame: Baseline, 6 weeks). The study lists 3 primary outcomes in all. 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 Jun 2024.