Intravascular Volumes in Hypoxia During Antarctic Confinement (ANTARCV)

Ecole Nationale des Sports de Montagne

Status: Invitation-only

Conditions: Hypoxia; Confinement

Treatments: Other: venous blood sampling; Other: 24-hour blood pressure; Other: apnea-hypopnea index and nocturnal oxygenation; Other: physical activity monitoring; Other: carbon-monoxide rebreathing

Study type: Interventional

Funder types: Other

Identifiers

NCT04106401

2018-A03243-52

Details and patient eligibility

About

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.

Full 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.

Enrollment: 24 estimated patients

Sex: All

Ages: 18 to 65 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• 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

Exclusion criteria

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

Trial design

Primary purpose: Basic Science

Allocation: Non-Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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24 participants in 2 patient groups

hypoxia & confinement

Experimental group

Description:

Participants exposed to high-altitude hypoxia and confinement during a one-year stay at Concordia station, Antarctica (3200 m)

Treatment:

Other: apnea-hypopnea index and nocturnal oxygenation

Other: physical activity monitoring

Other: carbon-monoxide rebreathing

Other: 24-hour blood pressure

Other: venous blood sampling

confinement

Active Comparator group

Description:

Participants exposed to confinement during a one-year stay at Dumont d'Urville station, Antarctica (sea level)

Treatment:

Other: apnea-hypopnea index and nocturnal oxygenation

Other: physical activity monitoring

Other: carbon-monoxide rebreathing

Other: 24-hour blood pressure

Other: venous blood sampling