NASA Prebreathe Study

NCT06740305 | Suspended Phase 1 DMC FDA Drug

• 2 other identifiers: Pro0011684680NSSC24PB887
• Study Type: interventional
• Target: 12
• Locations: 1 country
• Sites: 1

Brief Summary

This study will validate the experimental method and chamber facility at the Duke Center for Hyperbaric Medicine \& Environmental Physiology and test team capabilities to support NASA decompression sickness (DCS) studies. This project is related to development of protocols for extravehicular activity (EVA, "spacewalks") to minimize the risk of decompression sickness. Duke will perform four test days, collecting and recording data each day. Each test day will involve 3 volunteer subjects ages 18-50 years, who will breathe 100% oxygen for 6 hours. This will be followed by 6 hours in the hypobaric chamber at 1/3 atmosphere, during which subjects will perform various tasks, including arm and leg exercises, and undergo ultrasound testing to detect vascular bubbles. End-points will include bubble scores, and decompression sickness (DCS). If subjects develop DCS symptoms they will immediately be recompressed to ambient pressure and be assessed and treated.

Conditions

Decompression Sickness

Keywords

Space; Microgravity; Decompression; Decompression sickness; Altitude

Outcome Measures

Primary Outcomes (1)

• Number of participants with each type of decompression sickness

  Mild DCS (Type I), Uncomplicated: Symptoms involving joint pain, peripheral nervous system, or simple skin bends that resolve upon repress or within the first 20 minutes of treatment. Mild DCS (Type I), Complicated: Symptoms involving joint pain, peripheral nervous system, or simple skin bends that DO NOT resolve upon repress or within the first 20 minutes of treatment. Mild DCS (Type I) - Repetitive: Mild DCS symptoms involving joint pain, peripheral nervous system, or simple skin bends that occur after a successful treatment and within 30 days of a prior case of DCS for ground-based exposure. These are considered discrete occurrences of DCS in response to chronologically discrete exposures. Serious DCS (Type II): Symptoms involving the Central Nervous System (CNS), cardiovascular system (circulatory collapse/shock), pulmonary system (chokes).

  24 hours

Secondary Outcomes (1)

• Number of participants with venous gas embolism

  24 hours

Study Arms (1)

Healthy Volunteers

EXPERIMENTAL

Each participant in this group will be exposed to simulated altitude.

Other: Altitude; Drug: 100% Oxygen

Interventions

Altitude OTHER

Subjects will be exposed to simulated altitude (30,000 ft, 4.3 psia) in a hypobaric chamber. This is the same ambient pressure to which astronauts are exposed during EVA ("space walks").

Healthy Volunteers

100% Oxygen DRUG

Oxygen pre-breathing prior to altitude or simulated high altitude exposure is routinely used by the Air Force, NASA and organizations such as Duke Medical Center to prevent and treat decompression sickness as well as for treatment of patients. Oxygen used for this study is medical grade.

Healthy Volunteers

Eligibility Criteria

• Age: 18 Years - 50 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Non-smokers
• VO2pk \>35 ml/kg/min (males)
• VO2pk \>30 ml/kg/min (females)

You may not qualify if:

• Pregnancy
• Lung and heart disease
• Hypertension
• Diabetes
• Musculoskeletal pain conditions
• Need for regular medications such as analgesics

Sponsors & Collaborators

• Duke University: lead
• National Aeronautics and Space Administration (NASA): collaborator

Study Sites (1)

Duke University Medical Center

Durham, North Carolina, 27710, United States

Location

Related Publications (2)

• Mollerlokken A, Blogg SL, Doolette DJ, Nishi RY, Pollock NW. Consensus guidelines for the use of ultrasound for diving research. Diving Hyperb Med. 2016 Mar;46(1):26-32.

  PMID: 27044459 BACKGROUND

• Le DQ, Dayton PA, Tillmans F, Freiberger JJ, Moon RE, Denoble P, Papadopoulou V. Ultrasound in decompression research: fundamentals, considerations, and future technologies. Undersea Hyperb Med. 2021 First Quarter;48(1):59-72. doi: 10.22462/01.03.2021.8.

  PMID: 33648035 BACKGROUND

Related Links

• Related Info

MeSH Terms

Conditions

Decompression Sickness

Interventions

Altitude; Oxygen

Condition Hierarchy (Ancestors)

Barotrauma; Wounds and Injuries

Intervention Hierarchy (Ancestors)

Environment; Ecological and Environmental Phenomena; Biological Phenomena; Environment and Public Health; Chalcogens; Elements; Inorganic Chemicals; Gases

Study Officials

• Richard E Moon, MD

  Duke University

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: November 19, 2024
• First Posted: December 18, 2024
• Study Start: May 5, 2025
• Primary Completion (Estimated): December 31, 2026
• Study Completion (Estimated): December 31, 2026
• Last Updated: November 26, 2025

Record last verified: 2025-11

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)