Human Research Program Flight Thigh Cuff

March 31, 2025 updated by: National Aeronautics and Space Administration (NASA)

Mitigating Headward Fluid Shifts With Venoconstrictive Thigh Cuffs During Spaceflight

Venoconstrictive Thigh Cuffs (VTC) are being evaluated to determine the effectiveness at reversing the headward fluid shift that occurs during weightlessness. If successful, future studies may be done to implement these as a CM to SANS. To support this effort, participants will participate in 2 preflight study sessions consisting of a VTC fit check and a baseline data collection without and with the VTC donned. Participants will also participate in 3 inflight study sessions: a VTC fit check on flight day 30 (FD30) and two separate data collection sessions on flight day 45 (FD45) and 45 days before landing (R-45). During the two in-flight data collection days, participants will be studied before and for up to 6 hours after donning the VTC.

Study Overview

Status

Enrolling by invitation

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

10

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Texas
      • Houston, Texas, United States, 77058
        • Johnson Space Center, National Aeronautics and Space Administration

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Astronauts participating in missions that are ≥2 months

Exclusion Criteria:

  • Having known allergies to proparacaine hydrochloride ophthalmic solution precludes participation in this study
  • Use of ethinyl estradiol Combined Oral Contraceptive (COC) pills precludes participation in this study
  • Having increased risk of venothromboembolism (VTE) based on preflight thrombosis/clotting related biomarkers precludes participation in this study

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Supportive Care
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Flight Thigh Cuff Crew Participants
Participants will participate in 2 preflight study sessions consisting of a VTC fit check and a baseline data collection without and with the VTC donned. Participants will also participate in 3 inflight study sessions: a VTC fit check on flight day 30 (FD30) and two separate data collection sessions on flight day 45 (FD45) and 45 days before landing (R-45). During the two in-flight data collection days, participants will be studied before and for up to 6 hours after donning the VTC.
Device: Venoconstrictive Thigh Cuff (VTC)
The VTC is an adjustable fabric cuff that is worn on the upper thighs to retain some fluid in the legs. It consists of wide straps and a buckle which allow it to be tightened, then velcro to secure the strap in the tightened position. There is also lacing that can be tightened for micro adjustments. Imbedded within the fabric strap is a bladder that is not used for increasing tightness but allows the pressure of the cuff to be measured and tracked.
Other Names:
  • Thigh Cuff

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Internal Jugular Vein (IJV) area
Time Frame: Thigh Cuff Measures 90 days before mission, after 45 days in mission, and 45 days before return
Measured using Ultrasound.
Thigh Cuff Measures 90 days before mission, after 45 days in mission, and 45 days before return
IJV pressure
Time Frame: Thigh Cuff Measures 90 days before mission, after 45 days in mission, and 45 days before return
Measured using the VeinPres device during Ultrasound.
Thigh Cuff Measures 90 days before mission, after 45 days in mission, and 45 days before return
Intraocular Pressure (IOP)
Time Frame: Thigh Cuff Measures 90 days before mission, after 45 days in mission, and 45 days before return
Measured using the Pneumatonometer.
Thigh Cuff Measures 90 days before mission, after 45 days in mission, and 45 days before return
stroke volume
Time Frame: Thigh Cuff Measures 90 days before mission, after 45 days in mission, and 45 days before return
Measured from data collected during Ultrasound.
Thigh Cuff Measures 90 days before mission, after 45 days in mission, and 45 days before return

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

National Aeronautics and Space Administration (NASA)

Investigators

  • Principal Investigator: Brandon R Macias, PhD, National Aeronautics and Space Administration (NASA)

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

March 24, 2023

Primary Completion (Estimated)

May 14, 2028

Study Completion (Estimated)

May 14, 2030

Study Registration Dates

First Submitted

March 7, 2024

First Submitted That Met QC Criteria

June 20, 2024

First Posted (Actual)

June 26, 2024

Study Record Updates

Last Update Posted (Actual)

April 1, 2025

Last Update Submitted That Met QC Criteria

March 31, 2025

Last Verified

September 1, 2024

More Information

Terms related to this study

Other Study ID Numbers

  • STUDY00000453

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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