NASA Hosts Working Group to Address Decompression Sickness Risks in Spaceflight and Ground Testing

In a significant stride toward enhancing astronaut safety, NASA’s Office of the Chief Health and Medical Officer (OCHMO) convened an independent assessment working group in June 2024, at the Johnson Space Center. The primary focus was to evaluate the implications of patent foramen ovale (PFO)—a small opening in the heart that remains after birth—in relation to decompression sickness (DCS) during spaceflight and its related ground testing.

Decompression sickness, a risk in the low-pressure environment of space, occurs when dissolved gas (mostly nitrogen) forms bubbles in the body, which can lead to severe physiological complications. The group's mandate was to understand how PFO might exacerbate these risks and to assess the viability of various mitigation strategies.

The session brought together experts from diverse fields such as cardiology, hypobaric medicine, spaceflight wellness, and military health. This collaborative effort was to parse through preceding experiments, current operational data from NASA, and case studies to make informed decisions on potential risks and countermeasures.

One intrinsic focus was on the PFO, which is present from birth in all humans but remains unfused in about 25% of the population, potentially increasing the risk of DCS by allowing gas bubbles to bypass pulmonary filtration. PFO-related concerns are heightened in hypobaric environments—as encountered in space—making this a critical area of study for astronaut safety.

A critical conclusion from this assembly was the varying impact of excluding individuals with PFO from space missions or treating PFOs, stating that it does not categorically diminish the risk of DCS but only slightly reduces it. The group emphasized that other physiological factors could have more substantial effects on DCS risk, and thus, should not be overlooked.

Interestingly, the team concluded that there is no current need for additional research specifically into PFO related to DCS and altitude exposure. The existing decompression protocols and safety measures were deemed sufficient to manage risks under present conditions. This included ensuring immediate access to medical treatment similar to the facilities available during space missions for ground-based testing environments.

The meeting encapsulated a holistic review of past and present data, strategies, and intellectual discourse on spaceflight safety relating to DCS and PFO. The findings stress the necessity of comprehensive safety protocols including effective pre-breathe measures and immediate treatment capabilities.

The comprehensive summary report made public by NASA’s OCHMO Standards Team underscores ongoing commitments and adaptations to astronaut health protocols. This pivotal work aims to refine risk assessments and preventative strategies to safeguard astronauts, thereby ensuring the success of future missions.

This transparency in scientific evaluation and adaptive safety measures not only highlights NASA's dedication to crew health but also serves as a benchmark for similar protocols in aerospace and other related fields.