The Medical Issues Associated with Long-term Spaceflight

Introduction

Space medicine can be defined broadly as "the practice of all areas of preventative medicine, including screening, health care delivery, and maintaining human performance in the severe environment of space and preserving the long-term health of space travelers." When people go into space, they are in a harsh, isolated, and physically difficult environment. The development of space medicine is essential for human space exploration. It facilitates survival, function, and performance in this potentially fatal and hazardous environment. It operates on the frontiers of exploration, science, technology, and medicine and is international, intercultural, and interdisciplinary.

The Possibilities of Long Distance Space Flight

NASA has engaged in space medicine for medically preventable diseases and trauma to enable longer space flights. Medically avoidable illnesses are more dangerous to astronauts than trauma. The crewmember is at danger due to mission stress and a lack of complete treatment capabilities on board the spaceship, which could lead to more severe symptoms than on Earth. The limited, isolated ecological system of the spacecraft makes disease transmission likely. Even if the sickness isn't transferred, the unwell crewmember's diminished abilities may endanger the others. As crewed mission durations increase and operational procedures become more complex, this will become more serious and dangerous. Not only is the crew's health and safety at risk, but the mission’s success rate is also compromised.

Returning an unwell crewmember early is costly and dangerous. Trauma surgery in zero-gravity is difficult due to blood sample containment. In an attempt to tackle these health issues and improve the possibility of long-term space travel, NASA has tried to implement the rHEALTH ONE initiative to improve on-orbit, moon, and mars travel. This capability is related to adverse health outcomes and performance decrements due to mission medical conditions and long-term health outcomes due to mission exposures. Long-duration missions may be jeopardized without onboard medical monitoring.

Medical Standards for Spaceflight

The most effective means of reducing the enormous physiological dangers posed by spaceflight is by thorough screening and prevention. Therefore, medical standards for spaceflight have traditionally played a significant role, with the purpose of excluding any pre-existing medical disorders that could endanger crew safety or mission objectives. The standards must take into account the anticipated mission profile and the individual's function within the larger crew. Astronauts have to follow stricter rules than professional pilots do. Exclusions include conditions such as;

1. Acute incapacitation (e.g., coronary artery disease, renal stones, epilepsy).

2. Interaction with the space environment or life support systems (e.g., bullous lung disease or asthma; incompatible with sub-aqua diving or spacewalks).

3. Incompatible situations with a long duration space mission (e.g., may need to exclude stable chronic conditions requiring regular medication)

Medical Challenges with Long-term Spaceflight

On numerous occasions, space explorers have experienced health issues while flying through space. Anemia, cardiovascular deconditioning, muscular degeneration, decreased bone density, weight reduction, height gain, upward fluid shift, and vestibular impairment are a few examples of such health issues. The lack of gravity is mainly to blame for nearly each of these abnormalities. Several of these issues are reversible because they are adaptable in nature, but changing them upon arriving back on Earth can result in new issues.

The constant bone degeneration linked to a poor calcium homeostasis represents the most difficult and unsettling of all these issues. Severe demineralization can happen following a 2 year stay in a microgravity environment, and this issue seems to be unfixable. The possibility exists that bone degeneration will emerge as the physiologically critical issue when it come to the length of interplanetary travel unless the process that causes demineralization is properly understood and precautionary treatments are implemented.

Medicine In Flight

During human spaceflight missions, it is likely that medical issues of variable complexity, severity, and urgency will arise. Different levels of care are necessary based on the nature of the problem, the availability of resources, and the time required to return to Earth.

- Ultrasound on ISS

Ultrasound is the primary diagnostic imaging technique aboard the ISS. Radiation from X-rays and CT scans is unsuitable in the space environment. Although magnetic resonance imaging (MRI) employs magnetism to make images, it is currently too huge to be a practical choice. Ultrasound, which utilizes sound waves to make images and is available in laptop-sized packages, allows for the imaging of a range of tissues and organs. Currently, it is utilized to examine the eyeball and optic nerve in order to determine the cause of alterations that NASA has observed primarily in long-term astronauts. NASA is also pushing the limits of ultrasound usage in regards to musculoskeletal disorders, as they are among the most prevalent and likely disorders to arise. The training of astronauts to utilize the equipment and the interpretation of collected images are significant obstacles to the use of ultrasounds on space missions.

- Ultrasound Microgravity

The Advanced Diagnostic Ultrasound in Microgravity Study is funded by the National Space Biomedical Research Institute and involves the use of ultrasound by astronauts, such as former ISS Commanders Leroy Chiao and Gennady Padalka, who are guided by remote experts in order to diagnose and potentially treat hundreds of medical conditions in space. The scope of this study has been expanded to include professional and Olympic athletes as well as medical students. It is expected that remote-guided ultrasonography would be utilized in emergency and rural healthcare circumstances on Earth. This study's findings were submitted to the journal Radiology for publication aboard the International Space Station, making it the first manuscript ever submitted from space.

Takeaway

Doctors and space medicine specialists will have to work together to evaluate and limit potential dangers to individuals having previous health issues which could be made worse by microgravity as space flight increases to involve regular citizens along with trained cosmonauts. Compared to experienced aviators, criteria for space explorers are more stringent. Issues that: I could result in immediate incapacitation (such as heart disease, kidney stones, or seizures); (ii) could interfere with the atmosphere in space or life support equipment. and iii) are unsuitable for a long-term, deep-space expedition.

Medical specialists are crucial for allowing humankind to set foot on Mars since, similar to Earth; healthcare is of the utmost significance in space. Researchers and medical professionals have learned about the effects of weightlessness on an individual's health because of humanity's joint achievement of space flight. NASA's space medical programme is geared on upcoming lengthy expeditions. Its objective is to conquer the biological obstacles that keep astronauts and cosmonauts secure, healthy, and performing at their best. Doctors and space medicine specialists will have to work together to evaluate and limit dangers to individuals having prior health issues that could be made worse by microgravity as space flight increases to involve ordinary citizens in addition to qualified cosmonauts.

References:

Tavassoli M. Medical problems of space flight. Am J Med. 1986 Nov;81(5):850-4. doi: 10.1016/0002-9343(86)90357-8. PMID: 3490786.