Doctors need to bone up on spaceflight risks

Space tourists will ask their GPs for advice, and they need to be ready to give it, researchers say. Andrew Masterson reports.

As space tourism takes off, passengers are unlikely to be as fit and healthy as professional astronauts.

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Civilian doctors need to start boning up on the medical implications of time spent in microgravity in readiness for the advent of commercial spaceflight, researchers warn.

Writing in the New England Journal of Medicine, Jan Stepanik, Rebecca Blue and Scott Parazynski, all of the Aerospace Medicine and Vestibular Research Laboratory at the Mayo Clinic in Arizona, US, outline the potential challenges to doctors and their patients of a widely predicted shift from a state to a privately funded space industry.

Until now, they say, all astronauts have been rigorously healthy and fit people who have to match the high standards imposed by NASA and other state-owned space agencies around the world.

This, they note, is all about to change.

“The emergence of privatised commercial spaceflight is expected to afford paying customers, including those with pre-existing health conditions, the opportunity to fly in space,” they write.

And this means that many GPs in the coming years will be faced by patients who want to know if they have what it takes to blast off.

Doctors therefore will need to be familiar with the potential hazards and risks of space travel, and to assess each patient’s ability to withstand them. Crucially, Stepanik and colleagues point out, GPs will not be required to formally approve anyone’s wish to head for the stars, but, even so, any information they provide may have legal ramifications.

Obvious challenges for would be space tourists (or asteroid miners) include the immense stress on the body occasioned by rocket take-off, and the anxiety and discomfort that can be triggered by the noise and motion involved.

Beyond that, however, health matters can become complicated, in ways with which neither patients nor community doctors may be aware.

Even comparatively minor issues can arise during spaceflight, ranging from facial puffiness, due to shifting internal fluids, to back pain arising from slight spinal lengthening in microgravity.

Many astronauts have reported the inability to pee for the first few days. This issue, the authors note, usually self-resolves and “rarely requires a temporary period of self-catheterisation”.

However, they add, with admirable understatement, “for the lay participant, such experiences may greatly reduce enjoyment of the flight.

“Furthermore, self-catheterisation adds additional risks such as microtrauma and the introduction of infection, altering the mission risk profile and introducing a potential need for more comprehensive medical evaluation or care.”

Being the guy who stuffed up the return trip to the moon because he couldn’t pee properly is not, one might imagine, a reputation to be desired.

Longer flights, such as those to Mars, pose more serious problems, especially loss of bone density in the spine, pelvis and neck. A number of inflight strategies can ameliorate the danger, Stepanek and colleagues note, including “consistent resistance and aerobic exercise, nutritional support, and use of antiresorptive medications [which] have been shown to help preserve bone density”.

Nevertheless, loss of bone density and consequent loss of muscle tone can cause serious readjustment problems once travellers return to Earth and normal gravity – although, for the moment, the risks are confined to a very small cohort.

“The detrimental effects of prolonged microgravity on bone and muscular architecture are more likely to affect career astronauts, until participants in commercial spaceflights have opportunities to take part in long missions,” the researchers write.

Another potential problem lies in changes to the shape of the eye, and the potential vision damage arising therefrom. To date, however, the issue has only been reported once among career astronauts, and there is uncertainty whether the cause is physiological, in which case it’s a risk for all future space travellers, or genetic, in which case it isn’t.

Unpleasant circumstances that can arise from space journeys, the authors add, are not only physical in nature.

“Isolation from friends and family can be a challenge on long missions, as can conflict among flight participants,” they note.

This implies that even though on commercial space flights all passengers are onboard because they want to be, there is still the possibility that the reality of the situation – or the endless and offensive opinions of the person in the next seat – might cause someone to flip out.

Stepanek and colleagues recommend careful monitoring and assessment of passengers during pre-flight training to try to spot conflicts and meltdowns before they happen.

No matter how well prepared, and well screened, commercial space flight passengers may end up being, accidents and medical crises are still going to happen from time to time. And when they do, the authors note, on anything but a very short suborbital flight, the prognosis is unlikely to be good.

“In the event of a serious injury during a long flight, the probability of a successful medical evacuation or complex longer-term care while on board the space vehicle is low,” they say.

Onboard medical equipment and the medical skills of flight crew are both likely to be limited, and communication with Earth-bound doctors will be subject to long delays – as much as 40 minutes in the case of Mars journeys.

The authors do not spell out the likely result of a serious injury or disease in deep space, but, arguably, they don’t have to.

As on Earth, so in space: when medical procedures and decisions are to the fore, legal matters follow closely behind.

The authors take care to stress that a shift away from career astronauts to members of the public on board space craft will also entail a shift in legal parameters.

The US Federal Aviation Administration (FAA) has already taken steps in this area, decreeing that ultimately it is the responsibility of individual passengers to decide if they are fit enough to withstand the stresses and strains of a space journey.

However, such an idea is predicated on the principle of informed consent, and, the researchers say, “it is difficult to legally show that participants fully understand their risks and the legality of their own consent, raising concern about potential liability despite the consent process”.

To try to get on top of the myriad challenges looming for the medical community as the age of private space fight dawns, Stepanik, Blue and Parazynski urge “a strong collaboration among practicing clinicians, space medicine specialists, and the aerospace community” in order to protect the interests of all parties involved.

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