UT Southwestern Medical Center — Intracranial Pressure & SANS Countermeasures¶
Type: Academic Medical Center / Cardiovascular Physiology Research
PI: Benjamin D. Levine (Professor of Internal Medicine, UT Southwestern; Director, Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas)
Co-Is: Douglas R. Hamilton, Michael A. Williams (UW), Rong Zhang, Justin S. Lawley (Innsbruck)
Collaborators: University of Copenhagen (Lonnie G. Petersen), Rigshospitalet Denmark, University of Colorado
Outcome Category: Research Infrastructure → SANS Countermeasure Development + Terrestrial Clinical Application
Investigated: Session 27, 2026-04-06
Last updated: Session 75, 2026-04-07
Summary¶
Benjamin Levine's group at UT Southwestern used FO parabolic flights to make the first direct measurements of intracranial pressure (ICP) in microgravity — a fundamental dataset for understanding Spaceflight-Associated Neuro-ocular Syndrome (SANS), which affects ~50% of long-duration astronauts. The team recruited cancer patients with implanted Ommaya reservoirs (chemo ports in their skulls), providing a unique ethical pathway to invasive ICP measurement during zero-g flight. The parabolic flight data directly led to development of a Lower Body Negative Pressure (LBNP) sleeping bag (with REI) as a non-invasive SANS countermeasure, published in JAMA Ophthalmology (2021) and covered by CNN, ScienceDaily, and SYFY Wire. The research also has terrestrial clinical applications for patients with traumatic brain injury and intracranial hypertension. This is one of the highest-impact FO medical research projects, with 4+ peer-reviewed papers directly attributable to FO flight data.
FO Project¶
| Project | Title | TRL | Period | Status |
|---|---|---|---|---|
| 93937 | Effects of Microgravity on Intracranial Pressure | 6 → 7 | 2014-07 – 2015-09 | Completed |
What Was Tested¶
Core experiment: Direct, invasive measurement of intracranial pressure during parabolic flight microgravity phases. Two types of subjects with implanted cranial access: 1. Neurosurgical patients (n=6) with parenchymal ICP-sensors (tip-transducer catheter through frontal burr hole) 2. Former cancer patients (n=4) with Ommaya reservoirs (fluid-filled pressure transduction from lateral ventricle)
Lower Body Negative Pressure (LBNP) was applied at increments of 10 mmHg (0–50 mmHg) in both supine and 15° head-down tilt positions, while continuously monitoring ICP, blood pressure, and cerebral perfusion pressure (CPP).
Key finding: LBNP of 20 mmHg is the optimal level to reduce ICP without impairing cerebral perfusion pressure. The dose-response is non-linear — most benefit comes in the first 20 mmHg.
Downstream Impact¶
Publications (4+ directly from FO data)¶
- Petersen et al., J Physiol 597.1, 2019 (DOI: 10.1113/JP276557) — "Lower body negative pressure to safely reduce intracranial pressure." First demonstration of LBNP dose-response for ICP reduction using direct invasive measurements. 12 pages, n=10. TechPort file 368294.
- Lawley, Babu et al., J Appl Physiol 2020 — "Daily Generation of a Footward Fluid Shift Attenuates Ocular Changes Associated with Head-Down Tilt Bedrest." TechPort file 368293.
- Choroid engorgement / SANS model paper — TechPort files 368291, 368292. Effect of nightly LBNP on choroid engorgement in a SANS model.
- Hearon et al., JAMA Ophthalmology 2021 — "Effect of Nightly Lower Body Negative Pressure on Choroid Engorgement in a Model of Spaceflight-Associated Neuro-ocular Syndrome: A Randomized Crossover Trial." The sleeping bag countermeasure paper.
LBNP Sleeping Bag Countermeasure¶
The FO parabolic flight data established the dose-response relationship that informed the design of a collapsible LBNP sleeping bag, developed in collaboration with REI. The concept: astronauts wear the bag around their waist during sleep, applying ~20 mmHg suction to pull fluid toward the lower body, simulating the gravitational "unloading" that occurs on Earth when standing. Results published in JAMA Ophthalmology (2021) showed LBNP during sleep may be an effective countermeasure for SANS.
Media coverage: CNN, ScienceDaily, SYFY Wire, SciTechDaily, EurekAlert, Ophthalmology Times (Dec 2021).
Terrestrial Clinical Application¶
The J Physiol 2019 paper explicitly identifies LBNP as a potential non-invasive treatment for terrestrial patients with elevated ICP (traumatic brain injury, intracranial hypertension). Unlike head-up tilt, LBNP reduces ICP without reducing arterial blood pressure to the brain — a clinically significant advantage.
PI Recognition and Current Program (Session 75 update)¶
- Jeffrey P. Sutton Scientific Achievement Award (2021) — Space Medicine Association, "recognizes an individual or team for research with significant scholarship, innovation, and impact for space medicine"
- AAS 2024 Space Life Sciences Award — "exceptional scientific leadership to ensure human health and performance for the benefit of spaceflight"
- WMS 2025 Founders Award — Wilderness Medical Society recognition for decades-long commitment to wilderness medicine
- $3.8M, 13-year NASA grant (active) — studying cardiovascular adaptation to long-duration spaceflight in preparation for exploration-class missions to Mars
- SpaceX consulting — Levine consults with NASA and SpaceX on cardiovascular medical problems related to spaceflight
LBNP sleeping bag ISS deployment status (Session 75): Still not deployed to ISS as of April 2026. The JAMA Ophthalmology 2021 paper was ground-based (head-down tilt bedrest study). No ISS flight experiment has been announced. However, the concept is being validated by other teams: Texas A&M (Dr. Ana Diaz Artiles) conducted LBNP parabolic flights with Novespace in France (Nov 2025) — testing personalized LBNP countermeasures in actual microgravity. The LBNP-for-SANS concept is gaining traction but Levine's sleeping bag specifically has not flown.
Ongoing SANS Research at NASA (Session 75 update)¶
- Mini OCT project 157621: JSC active project (2022–2029, TRL 5→9) developing miniaturized OCT for Artemis missions — directly serves the SANS monitoring pipeline that Levine's ICP research feeds.
- SANS-CNN (npj Microgravity 2024): Machine learning applied to astronaut OCT imaging data for automated SANS detection.
- npj Microgravity 2025 systematic review: "Understanding the relationship between intracranial pressure and spaceflight associated neuro-ocular syndrome" — directly builds on Levine's foundational ICP measurements.
- npj Microgravity 2025: "Non invasive monitoring for spaceflight associated neuro ocular syndrome: responding to a need for in flight methodologies" — methodology paper for in-flight SANS monitoring.
- Life Sciences in Space Research 2025: "The case for anterior segment optical coherence tomography (AS-OCT) for the international space station and future planetary spaceflight" — advocates expanding OCT from posterior to anterior segment monitoring.
- npj Microgravity 2026: "Anterior segment biomechanics and intraocular pressure in microgravity: implications for future spaceflight studies" — extends SANS research to corneal/anterior segment effects.
- ScienceDirect 2025: "Artificial Intelligence Deep Learning Models to Predict Spaceflight Associated Neuro-Ocular Syndrome" — AI/ML applied to OCT data.
- ESA Head Down Bed Rest campaigns 2025–2026: Planned to study artificial gravity effects on SANS and vestibular system — the countermeasure research continues internationally.
- Texas A&M LBNP parabolic flights (Nov 2025): Dr. Ana Diaz Artiles testing LBNP in actual microgravity with Novespace — directly descended from Levine's foundational LBNP-ICP work.
Timeline¶
| Year | Event |
|---|---|
| 2014–2015 | FO parabolic flights: direct ICP measurement in microgravity (n=10 subjects) |
| 2019 | J Physiol paper: LBNP dose-response for ICP (Petersen, Lawley, Levine) |
| 2020 | J Appl Physiol: Footward fluid shift attenuates ocular changes |
| 2021 | JAMA Ophthalmology: LBNP sleeping bag randomized crossover trial |
| 2021 | Major media coverage (CNN, ScienceDaily) |
| 2024 | AAS Space Life Sciences Award; SANS-CNN ML paper (npj Microgravity) |
| 2025 | WMS Founders Award; npj Microgravity systematic review on ICP and SANS; AS-OCT case paper; ESA bed rest campaigns begin; Texas A&M LBNP parabolic flights (Nov) |
| 2026 | npj Microgravity: anterior segment biomechanics in microgravity; LBNP sleeping bag still not ISS-deployed |
Maturation time: FO flight (2014) → countermeasure validation (2021) = 7 years; FO flight → ongoing research pipeline = 12 years and counting
Status: Active research pipeline feeding Artemis SANS mitigation; PI recognized as field leader with Sutton (2021) + AAS (2024) + WMS (2025) awards; $3.8M 13-year NASA grant active; LBNP concept validated on ground but awaiting ISS flight test
Verification¶
- Sample size: 1 FO project, 10 subjects with direct ICP access, 4+ publications, 3 major awards
- Query used:
techport_get_project(93937),techport_get_document(368294), web search for PI publications, UTSW faculty page, phys.org LBNP article (Session 75) - Counter-query (Session 75): LBNP sleeping bag deployment on ISS — still not deployed as of April 2026. Ground-based validation only. Texas A&M conducting separate LBNP microgravity tests (parabolic flights, Nov 2025).
- Confidence: Confirmed for publications and countermeasure development. Suggestive for ISS deployment timeline — no flight experiment announced.
Cross-References¶
- Related SANS monitoring: Wyle OCT (FO→ISS SANS diagnostic)
- Related medical device: Henry Ford ultrasound (FO medical → ISS protocol)
- Related medical device: MGH NINscan (FO→clinical use)
- Related ECLSS health: UofL Aqueous Surgery (surgical microgravity)
- Archetype: Research Infrastructure → Countermeasure Development — FO provided the foundational physiological data that enabled a countermeasure engineering program. Different from "technology validation" — here FO enabled basic science that informed applied engineering.
Updated: Session 75, 2026-04-07