In a telemedicine case that would have been handled routinely on Earth, but a first for space medicine, an astronaut two months into a six month stint on the International Space Station was diagnosed and treated for a blood clot in the jugular vein.
According to Dr. Maja Zaric, a cardiologist familiar with the case, "The size and proximity of the...clot to the heart could have easily put [the crew member] into harm's way."
Although the astronaut showed no symptoms of vein blockage -- no headache or facial redness -- the jugular vein was abnormally "prominent" during a physical exam, and a follow-up ultrasound confirmed a clot.
There are two pairs of jugular veins that normally carry deoxygenated blood back from the head and neck to be pumped through the heart and lungs. While not optimal, blood will drain through the other in the event of restricted flow through one (there are rare conditions where individuals have only one, or even an extra, jugular vein).
After multiple "telemedicine" discussions with medical staff back on Earth, it was decided that the astronaut would be treated with the blood thinner enoxaparin (Lovenox), 20 vials of which had been part of the space station's medical kit.
The dosage was reduced due to the limited supply and after 42 days the medication was switched to apixaban (Eliquis), which was flown up for the purpose.
The clot slowly shrank over months of treatment, but blood flow through the jugular was still not fully back to normal, even three months after treatment.
However, when the astronaut finally returned to Earth -- and normal gravity -- blood flow in the jugular returned to normal, and treatment was discontinued. In fact, 10 days after landing the clot was gone.
Medication was discontinued four days prior to returning to Earth.
Discovery of the issue was largely a case of luck. The crewmember was taking part in a vascular research study along with other astronauts.
"In six out of 11 studied astronauts, there was abnormal venous flow detected," she said. Instead of the steady forward movement that pushes blood through veins, the astronauts exhibited a "to and fro" or "sloshing" movement, Zaric explained. That does not "ensure effective return of head and brain blood back to the heart," she said.
In essence, gravity appears key to healthy blood flow, and without it a "stasis" appears to occur within vessels, Zaric said.
The case highlights another danger astronauts face from prolonged weightlessness and reduced gravity environments such as might be experienced during prolonged travel and stays on the moon and Mars.
Venous Thrombosis during Spaceflight, New England Journal of Medicine (DOI: 10.1056/NEJMc1905875)
(Score: 4, Informative) by takyon on Sunday January 05 2020, @03:04AM (11 children)
It's about time to build a rotating station [wikipedia.org] to prevent these obvious health issues. Or stop hanging around in LEO.
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(Score: 2) by barbara hudson on Sunday January 05 2020, @03:20AM (8 children)
If the money hadn't been diverted to the space shuttle, there'd already be a permanently occupied moon base. No need for rotation when you can have real 1/6 g.
As for blood clots in the jugular, I guess there's never a Space Vampire [wikipedia.org] around when you need one.
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(Score: 0) by Anonymous Coward on Sunday January 05 2020, @03:57AM (7 children)
Likely not to be enough for veins, as we know it won't be enough for muscles and bones. We need good artificial gravity in space, that alone will make very long stay possible, and that is needed for getting to the main asteroid belt and working there. Artificial gravity on planets is more difficult.
(Score: 2) by takyon on Sunday January 05 2020, @04:57AM (6 children)
Long term stays in a science base on the Moon's surface are likely by 2040-2050. That will allow testing of the health effects, which should be no worse than long term habitation of the ISS unless they snort regolith.
Another cool idea would be to use artificial gravity to simulate 0.16g or 0.38g. That should lower the required speed and/or radius of the wheel.
Too bad that the Nautilus-X ISS demonstrator was never funded.
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(Score: 0) by Anonymous Coward on Sunday January 05 2020, @06:00AM (5 children)
The formula is a = (v^2)/r so I think you meant that it would increase the required radius.
(Score: 3, Informative) by takyon on Sunday January 05 2020, @07:31AM (4 children)
https://www.artificial-gravity.com/sw/SpinCalc/ [artificial-gravity.com]
10 meters
9.456528152601877 rotations/minute
9.90285312422637 m/s
1.0g
10 meters
4.728264076300938 rotations/minute
4.951426562113185 m/s
0.25g
5 meters
6.686775183186282 rotations/minute
3.5011872986174275 m/s
0.25g
I don't know if I described it correctly, but you can lower both the "speed" and radius at the same time (the third scenario above) by targeting a lower "gravity".
Lowering the radius should mean less mass.
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(Score: 0) by Anonymous Coward on Sunday January 05 2020, @06:00PM (2 children)
How would you safely get into and out of the rotating part of the station? What about making up the loss in rotation speed when the rotating part takes on more mass with a person entering?
(Score: 2) by takyon on Sunday January 05 2020, @08:57PM
I think you need to dock at the center, and have astronauts move from the rim towards the center or vice versa.
Slight changes in the rotation speed should be temporary, not devastating. Making the station more massive could reduce this effect.
Here's one scrappy concept:
https://gatewayspaceport.com/von-braun-station/ [gatewayspaceport.com]
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(Score: 2) by All Your Lawn Are Belong To Us on Monday January 06 2020, @03:26PM
There's more than one way depending on the design, but let's see if I can describe one of them in words.... You have a rotating wheels with hollow hub center that rotates with the wheel on either side of a hollow tube axle. The part between axel and hub are connected but only the hub is rotating. You dock at the center of the axle (not the hub! the axle isn't spinning....)
Float along the inside of the axle until you reach the hub at the end. You just float through the opening because, being at the center, there's no appreciable centripetal force there. The hub will be spinning but you will be stationary relative to the axel. But when you grab the distal end of the hub you will start spinning with the rotating motion. At this point you'll be stationary relative to the hub but spinning relative to the axel. You then crawl "down" the spokes of the wheel to the spinning tire where the centrifuge is applying its force.
Getting back out is similar. Crawl from the tire "up" the spoke to the center of the hub. When you get there you will still be spinning with the hub. But push yourself through the center between hub and axel.... you'll still be spinning at the rate of the hub. Grab a handhold in the axel and your spinning motion will stop and you'll be stationary relative to the axel. (Actually I'd probably get free of all connections with the hub and grab a handhold just inside the axel so that my rotation stops... the hub will be spinning around me but that's OK, I just pull myself into the axel that I'm now aligned with).
This sig for rent.
(Score: 2) by Muad'Dave on Monday January 06 2020, @01:10PM
Those radii are far too small to prevent differential head-to-toe acceleration and Coriolis effect nausea [wikipedia.org].
(Score: 0) by Anonymous Coward on Sunday January 05 2020, @06:47AM (1 child)
That simply isn't a good structure. Shielding is poor. Strength could be a problem.
A better design would be more like an office building tethered to a counterweight. A convenient choice for the counterweight would be a nuclear reactor.
(Score: 2) by takyon on Sunday January 05 2020, @07:19AM
That could be a good approach. But if they want to do a wheel with proper shielding, just spam up a huge overall mass with Starships. Especially if it is just staying in LEO, where you don't need to send additional Starships to refuel a single Starship load. Optimistic scenario = 150,000 kg per $2 million. Even if it turns out to be 100,000 kg per $20 million, that's still cheap.
Now a Stanford torus, that would be expensive no matter what.
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(Score: 2) by shortscreen on Sunday January 05 2020, @08:06AM (3 children)
I take it this was supposed to say that there is one pair of two veins, not two pairs.
(Score: 4, Informative) by RandomFactor on Sunday January 05 2020, @02:56PM (2 children)
Four of a kind?
11 Striking Facts About the Jugular [mentalfloss.com]
I actually feel kinda bad I didn't know this.
В «Правде» нет известий, в «Известиях» нет правды
(Score: 2) by shortscreen on Sunday January 05 2020, @08:02PM
Two on each side then. +1 informative
(Score: 1, Informative) by Anonymous Coward on Monday January 06 2020, @04:57PM
Yes, but what GP misses is that the external jugulars, like the external carotids, serve the outside of the skull and the internal jugulars, like the internal carotids, serve the interior of the skull. A big difference when talking about redundancies. It doesn't matter at all that your external jugulars are fine if you're having an ischemic stroke. And it doesn't matter how many drains out if you have an arterial blockage. (Although the brain does have the Circle of Willis and other rather amazing ways it will try and route around damage).
(Score: 0) by Anonymous Coward on Monday January 06 2020, @04:40PM
Lovenox and Eliquis don't treat the clot itself, rather it keeps the clot from growing larger by making further clotting difficult. They counted on the clot naturally reducing itself, because Tissue Plasminogen Activator (TPA) which would actually break the clot is somewhat risky to use in the neck (if the clot breaks free before dissolution, then it's headed to the narrower brain arteries, risking stroke,) and you don't give something that actually completely breaks the body's ability to formulate clots without medical assistance right there. (Although the body does produce small amounts of TPA naturally, which is how the clot dissolved on its own). I wonder if administered TPA would cause any additional complications in a microgravity environment....