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HypoxiaANTARCVNCT04106401

Intravascular Volumes in Hypoxia During Antarctic Confinement

A study testing carbon-monoxide rebreathing, venous blood sampling and physical activity monitoring in people with Hypoxia and Confinement, run by Ecole Nationale des Sports de Montagne at 1 site in France.

Unknown status

Status not confirmed. The sponsor has not verified this record for over two years, so it may be out of date.

Official record
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Trial summary

This study evaluates the effect of hypoxia on blood volumes during Antarctic winter-over confinement. Half of the participants will be evaluated during sea-level winter-over confinement, while the other half will be examined during high-altitude hypoxia winter-over confinement. Read more about this study

Who is it for?
Ages 18 to 65 yearsHealthy volunteers can take part
Conditions the study is for
Hypoxia, Confinement
What is being tested?
carbon-monoxide rebreathing, venous blood sampling and physical activity monitoring
Could I receive a placebo?
No, everyone receives an active treatment
How many people
24 participants
Where
1 siteFrance
Study dates
27 Sep 2019to 31 Dec 2022
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 65 years
  • All sexes
  • Healthy volunteers accepted
  • Adult, Older adult

Who may be able to join

  • Affiliated to a social security scheme
  • Ability to communicate and read in English or in French
  • Signed written informed consent form after visit with a MD

Who cannot join

  • Pregnant, lactating or parturient women
  • Cardiovascular, pulmonary or neuromuscular disease
  • Vulnerable persons

Trial locations and contacts

1 site in 1 country.

France1 site

  • Ecole nationale des sports de montagne, site de l'Ecole nationale de ski et d'alpinisme

    Chamonix, Haute Savoie, 74400

Other trials in France

About this study

Official title: Alterations in Total Red Blood Cell Volume and Plasma Volume During a One-year Confinement in Antarctica: Effect of Hypoxia

This study evaluates the effect of hypoxia on blood volumes during Antarctic winter-over confinement. Half of the participants will be evaluated during sea-level winter-over confinement, while the other half will be examined during high-altitude hypoxia winter-over confinement.

Read the detailed description

INTRODUCTION: Short-term space flight induces an alteration of circulating blood volumes, termed "space flight anemia" and characterized by a decrease in total red blood cell volume (RCV) and plasma volume (PV). This haematological alteration is likely to persist during a long-term space mission and impact the astronauts' health, however this question remains unexplored. During a long-term space mission, the use of hypobaric hypoxia is considered for technical reasons, however the safety of hypoxia must first be verified because this environmental condition causes substantial physiological changes, in particular changes in blood volumes that may interact with the haematological effects of microgravity.

OBJECTIVE: using the Antarctic confinement model as a high-fidelity terrestrial analogue for long-duration space missions, the investigators hypothesize that 1) sea level confinement reduces blood volume by simultaneously decreasing RCV and PV, and 2) chronic hypoxia offsets the decrease in RCV and exacerbates the decrease in PV induced by confinement.

METHODS: blood volumes will be measured via the carbon-monoxide rebreathing method, repeatedly in two groups of participants, overwintering either at Dumont d'Urville (sea level) or Concordia (altitude 3200 m). The blood viscosity will also be measured, as well as the markers of erythropoiesis and iron metabolism.

PERSPECTIVE: Documenting if some degree of hypoxia during long-duration confinement may be beneficial or unfavorable in terms of blood volume regulation is potentially relevant information for the astronauts' health and safety during long-duration space missions.

Conditions
Hypoxia, Confinement
Being tested
carbon-monoxide rebreathing, venous blood sampling, physical activity monitoring, apnea-hypopnea index and nocturnal oxygenation, 24-hour blood pressure
Keywords
total red blood cell volume, plasma volume, total hemoglobin mass, total blood volume
Medical subject headings
Hypoxia

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • carbon-monoxide rebreathingOther

    Inhaled carbon monoxide (CO) administrated as a bolus into a rebreathing circuit serves as a marker to tag circulating hemoglobin molecules and to calculate total hemoglobin mass (Hbmass). The change in blood CO concentration from pre- to postadministration (delta carboxyhemoglobin concentration) and the dose of administrated CO allows for Hbmass determination. The other blood compartments (total red blood cell volume, plasma volume and total blood volume) are derived from Hbmass, hematocrit and/or hemoglobin concentration.

  • venous blood samplingOther

    venous blood sampling at rest to evaluate blood viscosity, erythropoiesis and iron metabolism

  • physical activity monitoringOther

    recording of physical activity by actimetry

  • apnea-hypopnea index and nocturnal oxygenationOther

    recorded by ambulatory sleep recording device

  • 24-hour blood pressureOther

    recorded by ambulatory device

Study groups in NCT04106401
Study groupRoleWhat they receive
hypoxia & confinementExperimentalParticipants exposed to high-altitude hypoxia and confinement during a one-year stay at Concordia station, Antarctica (3200 m)
Receives: Other: carbon-monoxide rebreathing; Other: venous blood sampling; Other: physical activity monitoring; Other: apnea-hypopnea index and nocturnal oxygenation; Other: 24-hour blood pressure
confinementActive comparatorParticipants exposed to confinement during a one-year stay at Dumont d'Urville station, Antarctica (sea level)
Receives: Other: carbon-monoxide rebreathing; Other: venous blood sampling; Other: physical activity monitoring; Other: apnea-hypopnea index and nocturnal oxygenation; Other: 24-hour blood pressure

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. total hemoglobin mass

    Physiological parameter, corresponding to the total amount of circulating hemoglobin, expressed in grams, and determined with the 10-min carbon-monoxide rebreathing method and blood carboxyhemoglobin measurements (expressed in %).

    Measured: 15 months

  2. total red blood cell volume

    Physiological parameter, corresponding to the total volume of circulating red blood cells, expressed in liters, and derived from total hemoglobin mass, hematocrit (expressed in fraction) and hemoglobin concentration (expressed in gram per deciliter).

    Measured: 15 months

  3. total blood volume

    Physiological parameter, corresponding the the total volume of blood, expressed in liters, and derived from total red blood cell volume and hematocrit.

    Measured: 15 months

  4. plasma volume

    Physiological parameter, corresponding to the total volume of plasma, expressed in liters, and derived from total blood volume and total red blood cell volume.

    Measured: 15 months

Secondary outcomes (11)

  1. blood viscosity

    Physiological parameter, corresponding to the dynamic viscosity of whole blood, expressed in centipoises, and determined by a cone/plate viscometer

    Measured: 15 months

  2. serum erythropoietin

    Physiological parameter, corresponding to the serum concentration of erythropoietin expressed in milli-International unit per ml, determined by a specific biological assay.

    Measured: 15 months

  3. serum hepcidin

    Physiological parameter, corresponding to the serum concentration of hepcidin, expressed in mmol per liter, determined by a specific biological assay.

    Measured: 15 months

  4. serum erythroferrone

    Physiological parameter, corresponding to the serum concentration of erythroferrone, expressed in ng per ml, determined by a specific biological assay.

    Measured: 15 months

  5. serum transferrin saturation

    Physiological parameter, corresponding to the serum transferrin saturation, expressed in %, derived from serum iron concentration (in µg/dl) and transferrin concentration (in mg/dl)

    Measured: 15 months

  6. serum ferritin

    Physiological parameter, corresponding to the serum concentration of ferritin, expressed in ng per ml, determined by a specific biological assay.

    Measured: 15 months

  7. serum soluble transferrin receptor

    Physiological parameter, corresponding to the serum concentration of soluble transferrin receptor, expressed in nmol per liter, determined by a specific biological assay.

    Measured: 15 months

  8. Physical activity

    Physiological parameter, corresponding to the level of daily energy expenditure, expressed in kilocalories per kg per day, determined by accelerometry.

    Measured: 15 months

  9. Apnea-hypopnea index

    Physiological parameter, corresponding to apnea-hypopnea events, expressed in events per hour, recorded by an ambulatory sleep recording device.

    Measured: 15 months

  10. Nocturnal oxygenation

    Physiological parameter, corresponding to pulse oxygen saturation, expressed in %, recorded by an ambulatory sleep recording device.

    Measured: 15 months

  11. 24-hour blood pressure

    Physiological parameter, corresponding to the mean arterial blood pressure over 24 hours, expressed in mmHg, recorded by an ambulatory device

    Measured: 15 months

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted27 Sep 2019
  2. Study start27 Sep 2019
  3. Primary completion31 Dec 2022 (estimated)
  4. Study completion31 Dec 2022 (estimated)

Resources

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
Non-randomised
Intervention model
Parallel groups
Model description
one group wintering at sea level and one group wintering at high altitude
Masking
None (open label)
Enrolment
24 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT04106401
Sponsor's protocol ID
2018-A03243-52
Acronym
ANTARCV
Status last verified
Sep 2022
First submitted
23 Sep 2019
Last updated
13 Sep 2022
Results posted
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No

Questions about this trial

What is this clinical trial studying?

A study testing carbon-monoxide rebreathing, venous blood sampling and physical activity monitoring in people with Hypoxia and Confinement, run by Ecole Nationale des Sports de Montagne at 1 site in France.

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 3 inclusion and 3 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: status not confirmed, as of the sponsor's last update on 13 Sep 2022. 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 France. 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?

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?

total hemoglobin mass (time frame: 15 months). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT04106401.

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 Sep 2022.

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