Risks of Decompression Sickness and Venous Thromboembolism during Spaceflight and Patent Foramen Ovale Implications
NASA’s Office of the Chief Health and Medical Officer formed a working group in August 2026 to review the most recent data related to extravehicular activity (EVA) prebreathe testing and decompression sickness (DCS) events, venous thromboembolism (VTE) in-flight occurrences, and patent foramen ovale (PFO) implication as they relate to NASA’s Artemis (lunar and beyond) missions. The recommendations from this working group are built upon and integrate the outcomes of previous working groups hosted by OCHMO.
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The purpose of this working group was to assemble a panel of experts to review the most recent data related to extravehicular activity (EVA) prebreathe testing and decompression sickness (DCS) events, venous thromboembolism (VTE) in-flight occurrences, and patent foramen ovale (PFO) implication as they relate to NASA’s Artemis (lunar and beyond) missions. The recommendations from this working group are built upon and integrate the outcomes of the September 2024 Assessment of Patent Foramen Ovale (PFO) as Related to Decompression Sickness (DCS) in the Spaceflight Environment and During Ground Testing (NASA/SP-20240010473), the April 2026 NASA Risk of Venous Thromboembolism in Spaceflight Working Group (NASA/SP- 20260005258/REV1), and the updated DCS prevention standard reviewed by the DCS panel in NASA-STD-3001 Volume 2 Human Factors, Habitability, and Environmental Health (NASA-STD-3001 Vol 2 Rev F), with a specific focus on risk mitigation interventions such as PFO closure.
The following is a summary of the working group’s recommendations: