How Doctors on Earth Treated a Blood Clot in Space

[Matt] Let's say you're on

an interplanetary mission to Mars,

million of miles from the nearest hospital,

and something in your body goes awry.

Houston we have a problem.

[Matt] Say a routine body scan reveals

a potentially life-threatening blood clot.

What on Earth, or in space I guess, do you do?

If that happens here on Earth

we rush someone to the hospital and we can intervene.

If that happens on the International Space Station

our options are incredibly limited.

[Matt] A recent article in

the New England Journal of Medicine

describes an unprecedented medical event

in which an astronaut on the International Space Station

developed a blood clot just two months

into a six month mission.

So how did NASA handle this unforeseen situation?

To find out we spoke to one of the co-authors

on the article, Dr. James Pattarini.

He's a NASA flight surgeon who's in charge of

astronaut's health before, during, and after space flight.

In this case, the patient's over

250 nautical miles overhead.

They're traveling 17,500 miles an hour

in orbit around Earth.

There's no sure thing in space flight.

Space flight's hard.

And so even the perfect plan, if it relies on

things that have a chance of failure,

may not be something you can execute.

Dr. Pattarini walked me through

exactly what happened during this uncertain time

on the space station.

NASA is keeping the identity of the astronaut secret

for privacy reasons, so none of the footage you see

will depict any of the actual events.

Walk us through, first of all,

how the blood clot was discovered.

It seemed like it was kind of by accident really.

This particular astronaut was participating in

a study called fluid shifts.

What comes as a part of that study

is a number of in-flight ultrasounds.

And upon analyzing them here on the ground

the team noted that there didn't appear to be

any blood flow in one of the large veins in the neck,

the internal jugular vein.

So when this was found we were of course

very concerned, not only because this was

the first time we'd seen this in space,

but because when these things are found on the ground

they can be potentially life-threatening.

So this came as a surprise both to the astronaut

and to you folks on the ground

because the astronaut wasn't really showing symptoms

that might indicate a blood clot.

There's no predisposing risk factors

for this individual whatsoever.

We do risk stratification on individuals

for whether they're at increased risk

of forming clots or not, this individual was not.

Terrestrially we're most concerned about

clots forming generally in the legs

with the concern that pieces could then break off

and cause what we call a pulmonary embolism.

It could go to the lungs,

which would be very dangerous and could threaten your life.

In space things work very differently

and one of the concerns is we don't know

what the natural history of this would be in microgravity.

When we found it we felt it

had not been there for very long.

You can tell this by how it looks on the ultrasound.

When a clot is relatively new it appears soft

and what we call friable.

So it's more likely to look like it could

break pieces off and go places.

I mentioned a risk of pulmonary embolism,

which is of course the other risk that we were concerned of,

is that it would extend upwards towards the brain.

These are things we're very concerned about.

We really were faced with two options.

It was either an early return of the astronaut,

and so cutting the mission short.

Or remain in place on station and treat,

and try to organize and stabilize this blood clot,

so that when the time did come to come home

that it would not pose as much of a risk.

Why not just say, okay, we're gonna bring you

home immediately and treat you on Earth?

Coming back to Earth is a very violent activity.

There's the G-forces of reentry,

the dynamics of being shaken around

like you're inside of a washing machine,

the chute coming out on any capsule,

followed by the car crash of the landing.

These are all considerations that

with a soft fresh clot we were very concerned

that the decision to simply come home

would take a patient who's asymptomatic

and doing fine and place them at risk

of dislodging a piece of this

and going to the lung on Earth.

So once the decision to treat was made

by the clinical care team things tend to move very quickly.

Fortunately we actually had a supply of

one type of anticoagulant, enoxaparin, that's an injectable.

We knew that we only had on the order of around 40 days

maximum of this injectable supply, and so that was not gonna

get us certainly to the end of the mission.

We were starting to manifest a resupply vehicle

with an oral medication called apixaban,

that takes up much less mass in space.

[Man] Destined for the International Space Station.

[whooshing]

Even with a perfect resupply something could go wrong.

We lose resupply vehicles all the time.

And so having your backup plan and your backup plan

to your backup plan, certainly when the the health

of a crew member is relying on it,

weighs very heavily on the patient care team.

Yeah, so you have your diagnosis,

but you are somewhat removed from the patient

in this unprecedented situation.

How do you go about treating somebody

who's on the space station while you're still on Earth?

In this case the astronaut is both tasked with

being patient and also tasked with

being the hands of the treatment team.

We take gravity for granted in a lot of ways.

And one of the ways is any time

you've look at a bottle with some fluid in it here

you see a nice meniscus, all the fluid goes to the bottom.

But really surface tension predominates in microgravity.

And so what you'll see is the fluid kind of

filling the interior, but leaving a cavity in the center.

If you want to get the fluid out

there's different techniques that astronauts have developed.

They can do centrifugation, where you literally

you'll see astronauts spin to try to use

centrifugal force to get the fluid

to collect in one part of the vial.

You can also kind of try to go around inside of the vial

with the bevel of your needle

and try to suck it up as you go.

But it's certainly a lot more complicated.

I'm also curious how you go about

choosing drugs to send to the International Space Station.

We've got nine medical kits on the space station.

They have a different kind of spectrum of medications

and medical supplies in each.

Going all the way back to Apollo,

they didn't know what they needed,

and so what they relied on was crew feedback.

You can go back to the Apollo mission reports

and what you'll see is that after every single mission

the contents of the medical kit changed.

And so if everyone agrees, for example,

that you need something for nausea.

Well there's a pretty broad spectrum of medications

that can be used for that, but if it's something injectable

then you think of all the mass and volume

that comes along with the needles and the syringes,

and the fact that they can't be reused.

And how do you sterilize things

if you do need to reuse them.

And all these things go into consideration of,

well maybe we'll have an injectable,

but how much of that are you gonna fly versus

how much of the oral medication,

which can be vacced very very tightly.

[Matt] The astronaut continued to take

the blood thinner throughout the mission.

NASA says that the astronaut's normal duties

were not affected by the additional medical care.

But the strangest and maybe most consequential part

of the event happened after the astronaut came home.

The last time we assessed it was the day prior to return

and we saw that there was still absent flow in microgravity.

We assessed it immediately upon bringing

the astronaut back to Earth and saw that

completely normal flow had been restored.

By 10 days after return there was no evidence of the clot,

you could not find any residual whatsoever.

Which really nails home that the microgravity environment

that we think is playing a significant role here.

[Matt] Upon further investigation in the study that

originally found the blood clot a new discovery emerged.

A former astronaut who had participated in the study

also showed signs of a possible blood clot.

Now there's 11 individuals as part of the study,

two out of 11, if real, is certainly concerning to us.

And there's flow abnormality seen in more than that.

If this is truly occurring in around 20% of our astronauts

it raises a number of questions.

Number one, has this really been happening for 50 years

and we're just finding it now?

It's absolutely possible.

Are there other risk factors that predispose

some people to developing these clots

and we just really don't understand

the interaction between microgravity

and those risk factors?

That's absolutely possible as well.

I think the biggest question though is,

if this has been occurring, and this is something

that we're just gonna routinely see in human space flight,

what does that mean for doing these

longer exploration class missions?

It's one thing when, as I said,

if something goes wrong we can get people home

in a number of hours from the International Space Station.

It's just not on the cards,

you're days away for anywhere, even the moon.

And certainly much longer if we go to Mars or anywhere else.

[Matt] And this isn't the only medical issue

that might complicate prolonged space flight.

There's something called space flight associated

neuro-ocular syndrome, we call it SANS for short.

This is also a relatively recent finding,

this is within the last decade.

It's a remodeling of the back of the eye,

and of the optic nerve sheath itself.

How do we prevent it, how do we treat it?

These are things we're still learning about.

And that's still relatively new,

that's within the last decade.

And now we see that there's changes in blood flow.

I think the question of how bad is microgravity,

we're learning it does worse and worse things

to the human body.

At first it was loss of bone density,

okay we've got that under control.

Okay now it's loss of muscle mass,

well we've got that under control as well.

Now it's this remodeling of the eye and the optic nerve,

we're getting smart on that

and we'll solve that eventually, I'm sure.

And now there's a propensity to form clots, perhaps.

And these flow abnormalities in the venous system.

And now every US astronaut who flies,

periodically in flight we are looking at these vessels,

and other large vessels with ultrasound

to understand those flow patterns better,

and to find if there's any other clots

that develop in any other crew members.

We evolved to need one G of gravity

and I think we need one G of gravity.

And so the question of, is one sixth G on the moon enough

if we're gonna live there for prolonged periods of time,

is that enough to make these things go away?

That's an open one.

I would say, probably not.

I think it'll adjust in part of the spectrum

but not the full thing.

I think 2001 with the big rotating space stations,

is there a solution, an engineering solution

to provide some level of gravity to our astronauts

to mitigate these types of physiological effects.

And I think eventually we're gonna need

something like that.

[Matt] As we venture farther and stay longer in space

it's likely we'll discover even more limits to our biology.

[HAL] This mission is too important

for me to allow you to jeopardize it.

[Matt] This incident is a reminder

that NASA must be ready for anything.

Because we aren't about to let the robots

have all the fun in space.