Weightlessness Associated Cephalad Fluid Shifts; The Potential to Evaluate Venous and Lymphatic Dysfunction

NCT06405282 | Completed FDA Device

• 1 other identifier: 2022-124
• Study Type: observational
• Target: 15
• Locations: 1 country
• Sites: 1

Brief Summary

In the weightlessness of space and significant alterations of terrestrial 1 g (1 gravity equivalent) head-to-foot hydrostatic pressure gradients, astronauts experience a dramatic fluid redistribution of \~ 2 liters from the legs to the head and neck within the first 24-48 hours of flight, among other cardiovascular and physiologic system adaptations. After only 4 days in the weightlessness of low earth orbit (LEO), changes can be seen in baroreceptor responsiveness, causing orthostatic hypotension upon subsequent return to Earth. Fluid shifts may also result in headaches, congestion or facial puffiness that can contribute to deteriorating sleep patterns. The ability to manage, mitigate, or offset these fluid shifts is vital to maintain nominal health for short and long duration space flight and potentially improve readaptation to terrestrial gravity or other surface gravity fields, such as the moon or Mars. Fluid shifts towards the cephalic region during microgravity have been speculated to contribute towards spaceflight associated neuro-ocular syndrome (SANS). SANS is a distinct, microgravity-induced phenomenon of neuro-ophthalmic findings observed in astronauts following long-duration spaceflight including choroidal folds, optic disc edema, posterior globe flattening, refractive shift, and cerebral fluid shifts noted to be persistent at 6-month post-flight MRI scans. Thus, noninvasive approaches to studying real-time fluid shifts in weightlessness could serve as critical areas of research to further SANS study and effective countermeasure protocol development. For continuous fluid shift monitoring and management, the goal is to establish baseline assessments utilizing real-time point- of-care noninvasive imaging devices (NIID). Manual lymphatic drainage (MLD) therapy reduces lymphatic fluid in the affected limb, head, and neck to improve function and prevent progression of fluid build-up. MLD is a therapeutic massage that delivers light pressure through the skin to stimulate lymphatic vessel function. Randomized controlled trials have demonstrated statistically significant improvements in lymphatic function and pain following MLD. The main objectives of this pilot, retrospective study were to use NIID to examine temperature differential alterations, superficial venous flow patterns (head, neck, upper torso), and venous flow patterns along the lymphatic ventromedial bundles of the medial calves and thighs when in the 6-degree head down tilt (HDT) validated space analogue position and to analyze the effect of MLD therapy administered in the HDT position on lymphatic flow and temperature. HDT is the best validated space analogue currently available for evaluation of fluid redistribution in a timely manner.

Conditions

Fluid Retention Tissue; Perfusion; Complications

Keywords

dermal flow; venous flow; fluid shift; manual lymphatic drainage; blood circulation; space simulation; diagnostic imaging; tissue temperature gradient

Outcome Measures

Primary Outcomes (3)

• Percent change (%) in TDC level from baseline

  TDC is a measurement of local tissue water content. The lymphatic fluid scanner will assess TDC levels at the timepoints listed below. The outcome measure is the percent change in these levels to assess change in interstitial fluid in simulated microgravity; the unit is percentage.

  Baseline, post-30 minutes, post-60 minutes, post-90 minutes, post-120 minutes, post-150 minutes, post-180 minutes, post-195 minutes (post-MLD), and post-225 minutes (30-minutes-post-MLD)

• Percent change (%) in tissue oxygenation saturation level from baseline

  Tissue oxygenation saturation is an indicator of perfusion changes. NIRS will assess tissue oxygenation at the timepoints listed below. The outcome measure is the percent change in these levels to assess perfusion changes in simulated microgravity; the unit is percentage.

  Baseline, post-30 minutes, post-60 minutes, post-90 minutes, post-120 minutes, post-150 minutes, post-180 minutes, post-195 minutes (post-MLD), and post-225 minutes (30-minutes-post-MLD).

• Percent change (%) in tissue temperature gradient from baseline

  Tissue temperature gradient measures the change in temperature at an area of interest compared to surrounding tissues. Fluid shifts are associated with tissue temperature alterations. LWIT will assess the tissue temperature gradient at the timepoints listed below. The outcome measure is the percent change in temperature gradients to assess changes in thermal energy at an area of interest in simulated microgravity; the unit is percentage.

  Baseline,post-30 minutes, post-60 minutes, post-90 minutes, post-120 minutes, post-150 minutes, post-180 minutes, post-195 minutes (post-MLD), and post-225 minutes (30-minutes-post-MLD).

Study Arms (1)

Healthy students of the Health Professions Division of NSU

Participants arrived at a predesignated room and acclimated to the ambient temperature for 15 minutes. Baseline heart rate, blood pressure, respiration rate, and oxygen saturation were taken and monitored throughout the data collection process. Participants were assessed in the HDT position (validated simulated weightlessness) for 3 hours and 45 minutes. Baseline image assessments were taken 1 minute after assuming the HDT position. Subsequent image assessments were taken every 30 minutes thereafter. Each image acquisition requires \~20 seconds and was performed by 1 of 4 trained imagers. Participants received 15 minutes of an established MLD protocol to the head, neck, and thorax before moving out of position. Immediately post-MLD, reassessment with the devices occurred. A follow-up reassessment was taken with the devices 30 minutes after MLD in the sitting position to assess potential changes and resolution of any symptoms experienced following a return to gravity environment.

Other: Manual Lymphatic Drainage; Device: Near infrared spectroscopy; Device: Temperature; Device: Tissue Dialectic Constant

Interventions

Manual Lymphatic Drainage OTHER

MLD is a gentle manual technique used to decongest swollen areas and redirect lymphatic flow to non-congested areas

Healthy students of the Health Professions Division of NSU

Near infrared spectroscopy DEVICE

Oxygen saturation measurement

Also known as: Kent Snapshot

Healthy students of the Health Professions Division of NSU

Temperature DEVICE

Thermal imaging

Also known as: Long wave infrared, Wound Vision Scout

Healthy students of the Health Professions Division of NSU

Tissue Dialectic Constant DEVICE

TDC captured by lymphatic fluid scanning device

Also known as: TDC, Delfin Lymphscanner

Healthy students of the Health Professions Division of NSU

Eligibility Criteria

• Age: 18 Years - 45 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)
• Sampling Method: Non-Probability Sample

Study Population

Healthy students between the ages of 18 and 45.

You may qualify if:

• Students at Nova Southeastern University
• Aged 18-45 years
• Body Mass Index ranging from 18.5 to 24.9
• No known lymphatic dysfunction
• Written informed consent

You may not qualify if:

• On blood pressure medications
• On vasodilation medications
• Uses any form of nicotine

Sponsors & Collaborators

• Nova Southeastern University: lead

Study Sites (1)

Nova Southeastern University

Fort Lauderdale, Florida, 33328, United States

Location

Related Publications (3)

• Michel CC. Starling: the formulation of his hypothesis of microvascular fluid exchange and its significance after 100 years. Exp Physiol. 1997 Jan;82(1):1-30. doi: 10.1113/expphysiol.1997.sp004000. No abstract available.

  PMID: 9023503 BACKGROUND

• Debiec-Bak A, Skrzek A , Prof, Wozniewski M , Prof, Malicka I. Using Thermography in the Diagnostics of Lymphedema: Pilot Study. Lymphat Res Biol. 2020 Jun;18(3):247-253. doi: 10.1089/lrb.2019.0002. Epub 2019 Nov 19.

  PMID: 31742482 BACKGROUND

• Barnhart H, Aviles F Jr, Pannunzio J, Sirkis N, Hubbard C, Hardigan P, Ginsburg S, Mayrovitz H, Eckert KA, Melin MM. Using noninvasive imaging to assess manual lymphatic drainage on lymphatic/venous responses in a spaceflight analog. NPJ Microgravity. 2024 Oct 3;10(1):93. doi: 10.1038/s41526-024-00429-w.

  PMID: 39362907 DERIVED

MeSH Terms

Conditions

Edema

Interventions

Manual Lymphatic Drainage; Spectroscopy, Near-Infrared; Body Temperature

Condition Hierarchy (Ancestors)

Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Massage; Therapy, Soft Tissue; Musculoskeletal Manipulations; Complementary Therapies; Therapeutics; Drainage; Physical Therapy Modalities; Rehabilitation; Diagnostic Imaging; Diagnostic Techniques and Procedures; Diagnosis; Spectrum Analysis; Chemistry Techniques, Analytical; Investigative Techniques; Vital Signs; Physical Examination; Physiological Phenomena

Study Officials

• Heather Barnhart, PhD

  Nova Southeastern University

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: observational
• Observational Model: CASE CONTROL
• Time Perspective: RETROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Study Record Dates

• First Submitted: April 4, 2024
• First Posted: May 8, 2024
• Study Start: April 14, 2022
• Primary Completion: June 25, 2022
• Study Completion: June 25, 2022
• Last Updated: May 8, 2024

Record last verified: 2024-05

Locations

US (1)