Medical Challenges for a new era of Spaceflight

NASA, the European Space Agency and commercial companies are planning manned missions in space, longer in distance and duration than ever before. NASA’s Artemis missions will see astronauts travel to the surface of the moon and launch the Gateway space station in its orbit. This will serve as the “gateway” for missions both to the moon and further.  

SpaceX, one of the collaborating companies, is already making rapid independent advancements and hopes to colonize Mars by the end of 2030. It’s Polaris Dawn mission will see astronauts travel the furthest humans have been since NASA’s Apollo program. Later in the mission, these astronauts are scheduled to conduct a spacewalk, which will make SpaceX the first commercial company to attempt Extra Vehicular Activity (EVA).  

For manned missions to commence, it is necessary to anticipate the medical needs of crew members while in space. Where rapid repatriation to earth is not possible, facilities for resuscitation, operative surgical intervention and life support are critical.  

Elon Musk, CEO of SpaceX, admitted in an interview when discussing space travel that “honestly, a bunch of people will probably die in the beginning”. A major issue to overcome is the size of conventional equipment. For long duration missions, compact, lightweight, multifunctional and alternative medical instruments are required. Historically, 1kg cost over $51,200 to send into our orbit. SpaceX has reduced this expense to approximately $200, hence their collaboration with NASA. 

Astronauts are chosen through a rigorous selection process to reduce the possibility of medical problems on board. Many experts agree that the biggest threat to a space mission is traumatic injury. Studies conducted on the ISS and during parabolic flights have shown that microgravity effects most physiological systems of the body. The most significant of these changes occur in the cardiovascular system, musculoskeletal system and skin/immune system. The variations in these systems cause astronauts to be vulnerable to shock, fractures, poor wound healing and infection. 

On Earth, the conventional way to assess a trauma victim is by Advanced Trauma Life Support. This utilizes an ABCDE approach to managing patients but requires adaption in microgravity. There is also the issue of skill required to perform an efficient primary survey, a skill that physicians develop through practice. Astronauts, however only receive 40 hours of medical training. 

The first stage of a primary survey is airway and cervical spine (C-spine) management, of which the crew will only have very basic training. They will receive training in video-assisted laryngeal intubations as it is deemed the safest mode of intubation in inexperienced hands, however it will be extremely challenging in microgravity. A laryngeal-mask airway will be available if intubation isn’t possible, but there is a risk of aspiration of stomach contents into the lungs. Immobilization of the C-spine would also be difficult in space. 

On long term missions, the respiratory system is one of the few physiological systems that is not detrimentally impacted. Therefore, a basic ventilator could assist in ventilation if required. The ultra-high definition Butterfly IQ ultrasound scope will be available to crew and has a multitude of applications in trauma. In the primary survey, it will be used to check endotracheal tube placement after intubation and to survey for lung pathology. This is necessary because auscultation, using a stethoscope to listen to the chest, is inaccurate in noisy spacecrafts. Tracheostomy (surgical airway) sets will be provided on missions should endotracheal intubation not be possible. NASA is still working on a chest drainage system for use in microgravity as current systems are gravity dependent and there is difficulty in engineering an appropriate suction system.  

The most life-threatening physiological change with respect to trauma occurs within the cardiovascular system. Astronauts get a syndrome called: ‘puffy-face chicken-leg syndrome’. This occurs when blood is drawn from extremities into the central compartment (thoracic and abdominal cavities) due to the lack of gravity. Homeostatic mechanisms activate causing hypovolemia. On average, astronauts experience a reduction of 10-15% of their blood volume. Reduced blood volume makes hemorrhage a major concern when treating trauma and peripheral canulation in the arms and legs difficult. NASA has created a machine called IVGEN which creates IV fluids from drinking water. It contains a gas-fluid separator filter to prevent air bubbles forming and infusions will be given via a closed pump system. Crew will have splints to immobilize fractures and hemostatic dressings to reduce blood loss. 

The assessment for disability and environmental alterations will remain similar to those used on earth. The Glasgow Coma Score assessment will still monitor severity of head injuries. However, in terms of environmental adjustment, the casualty could be suspended in low normothermia or mild hypothermia to improve outcomes if a return to earth is feasible. 

As spaceflight becomes more commonplace within government and commercial enterprises, there is increasing need to advance medical knowledge. With more and more manned missions occurring, medical emergencies will be inevitable. It is essential that space crews are provided with the best chance of survival. Innovation is needed to overcome the many medical difficulties of an extraterrestrial environment.