US Use in Operational Space Medicine and Soldier Medical Care and Why It Matters to You - SD

Introduction

Hi, my name is Dr. Rick Shering. I am a flight surgeon at the NASA Johnson Space Center.

I'm also a flight surgeon in the United States Army, Lieutenant Colonel at the US Army, a medical research laboratory in Fort Rucker, Alabama.

I've been in those positions for approximately the last 10 years.

Today I wanted to talk about topics that I think are very interesting for physicians, but in particular those who use ultrasound, primarily in musculal medicine.

First will have to do with the use of ultrasound in operational space medicine context, with regards to the injuries that we see with astronauts, both terrely and potential uses in space.

And then also the applications that we have in army and high performance jet aircraft pilots with regards to degenerative disc diseases, changes that occur in the cervical and the lumbar spine, and how we're actually using ultrasound to get a better idea of exactly what happens to the spine in these operational environments, where there's wear and tear over many, many hours of flight, and eventually they result in degener disc disease and disc herniation.

So that being said, there's a lot of slides to go through and we'll go ahead and do that, and hopefully you'll get something out of it.

Operational Use of Ultrasound in Space Medicine and Soldier Care

Today we're gonna talk about the operational use of ultrasound in space medicine and in soldier medical care, and in particular, why it would matter to you as a physician as a sonographer or sonologist.

And kind of discuss some interesting applications that most of you probably aren't aware of.

Speaker's Background

My background, again, I'm a flight surgeon at NASA Johnson Space Center and in the US Army.

I have the distinct privilege of working with unique individuals and very unique environments and the application of medicine and my love of flying in space is really what brought me to NASA Johnson Space Center about eight years ago.

I've been privileged to work with not only the current astronauts, but the Powell astronauts.

I was originally the moon Mars fight Stern when we had the Constellation program, and now I'm specifically involved in the musculoskeletal medicine, sports medicine effort at NASA Johnson Space Center to take care of astronauts and their musculal injuries.

So this slide to show some of the unique things we get to do and just the folks that I've actually gotten to work with.

Physiological Changes in Space Flight

So, as far as some of the things to give you a background about what happens to the body, both with short and long duration space flight, one of the most interesting areas we're dealing with right now is both in the neuro vestibular and the neuro ophthalmological areas.

Neuro-Vestibular and Neuro-Ophthalmological Areas

And in particular, there's a unique application for ultrasound use here to define a problem that we're seeing with elevated intracranial pressure.

And the concomitant swollen optic disc and cup within the neuro vestibular is also the most common condition is space.

I call space motion sickness, which I'll just talk about briefly, but it's something that about nine outta 10 astronauts will experience.

And we're not really sure why exactly it happens, but it's a very unique problem.

And fortunately, it's short lived.

Cardiovascular Changes

Just briefly mentioned cardiovascular changes.

Probably one of the most interesting things that occurs and has been well studied by multiple investigators is the fluid shift in space.

Approximately two liters of fluid shifts from the lower extremities up towards the core and the head, and this occurs fairly rapidly, when you flew in the space shuttle, you got into space from launchpad to lower earth orbit within about eight and a half minutes.

And this fluid shift would occur and you would basically get a big swollen head and talk kind of funny, and then eventually just feel like a race horse and get rid of all the fluid, and then you'd be euvolemic for space.

The unique problem was when you came back to Earth, that gravity pulled that fluid back down, and typically we would see orthostatic hypotension, among other things, that prompted us to do a fluid load before they came back from space fight, which seemed to work in a number of the astronauts.

There are other changes that occur, and they've been also looked at with echocardiography and ultrasound.

Ben Levine, Doug Hamilton, are some of the primary investigators in those areas as well.

Musculoskeletal Changes

The musculoskeletal here is my particular area of interest, grossly, we see about a 20 to 30% loss of muscle mass in the lower extremities, primarily because of disuse.

When you get into space, your arms become your legs.

And similar to being in a cast, astronauts really don't use your legs in microgravity.

Now, being on the moon or Mars would be a different story, but for microgravity purposes, you generally don't use your lower extremities.

With that in mind, we also see anywhere from about 0.7 to a 3% per month loss of bone marrow density from the baseline.

And that's particularly significant when you think about post-flight fractures, or what we've seen on one occasion in flight, during a Russian mission was a in-flight renal ssis or kidney stone.

The other thing that's very unique is that in some of our shuttle astronauts, we had about a dozen post-flight kidney stones that most likely was a result of the resorption of calcium from the bone and deposition in the renal kay.

In particular, though, with the musculoskeletal, we deal with, we see quite a bit of back pain.

About 53% of astronauts will complain about back pain.

About 12% of those are described excruciating back pain for reasons we're not unsure of.

We're hoping that ultrasound will shed some light on that.

But it is interesting to note that there's about a two to six centimeter elongation of the spine when you get into space, which in some individuals release existing back pain and other people without back pain causes back pain.

So that's also an area that is very interesting.

Unfortunately, we've had about 44 disc herniations in astronauts post-flight.

One actually occurred on landing.

And we're not really sure what the mechanism for that is, either, whether or not that distraction of the spine in space causes a destabilization of the annulus fibrosis and the predisposition for the nucleus to herniate out or what.

We're not really sure There's immune mepo changes that are interesting at this point.

Immune Changes

We don't see any real operational impacts to this.

In other words, we haven't had bizarre infections in space.

There's been no vast and drama to strains that have occurred, and there isn't really no particularly bad bleeding disorders.

It is interesting to note, though, that the astronauts will say it'll take about three or four weeks for these small paper cuts in their fingers to heal, and there is some delay in wound healing, which when we talk about items such as getting an appendicitis or cholecystitis on your way to Mars, what would be the proper approach to that?

Would you just go ahead and do a surgical procedure or would you try to treat them medically?

And that's something we grapple with quite a bit, and we think at this point, because of the inherent complications or difficulties with doing surgery in space, it would probably be prudent to treat them medically, although we would use ultrasound for any type of needle guided aspiration or other procedures in the event we had that problem.

Psychosocial Issues

And last but not least is the behavior of psychosocial issues.

Disruptions of the circadian rhythm, sleep disturbances, insomnia are some of the most common things we deal with after space motion sickness and low back pain in space.

And it's an area that some of our flight surgeons and our researchers around the world have actually shed some tremendous light into how to optimize performance.

In particular with the blue wavelength of light, primarily in the 450 to 550 nanometer range that actually can stimulate daylight settings actually indoors, which is very exciting from the terms of performance.

But not that the board you that any further.

Specific Conditions Where Ultrasound is Helpful

We're just gonna talk just very briefly about some of the specific conditions where ultrasound can be helpful.

Papilledema and Intracranial Pressure

And I described the pap edema that we see, for some reason, it may be related to the fluid shift.

You get a two liter fluid shift towards the head, and this may or may not contribute to this increase intracranial pressure that we've seen.

Some of the astronauts have described a painless visual change.

In other words, they don't get a headache, but they'll get this increase in intracranial pressure with the result in pap edema.

And when we've looked at their optic disc actually with ultrasound in space, we've seen cup and disc edema and increase in the optic nerve and sheath.

It's very interesting that in areas where the astronauts are exposed to increased pressure or carbon dioxide, they complain more of headaches.

But we certainly know that CO2 is the most post potent cerebral vasodilator.

And maybe because of irregular airflow in space, if you're exposed to a pocket of CO2, this could potentially expose you to vasso d dilatation and increasing your cranial pressure.

It's an area that we're using ultrasound in space, because that's the only imaging modality that we have.

It's actually very effective, and very exciting.

But this is a problem we'd really like to get more insight into and see if we can't understand the pathophysiology of that.

Musculoskeletal Conditions

I had mentioned that musculoskeletal conditions are also particularly numerous, relatively speaking.

We see your garden variety tendinosis, tendinopathies both on the ground and in space, and particularly in the shoulder knee, rarely in the Achilles, but occasionally in the elbow.

But the more interesting issue, again, has been the herniated disc issue.

And I have on this slide both a paper that we published in 2010 in the aviation space environmental Medicine journal regarding the risk of herniated nucleus pulis and astronauts.

And also a big summit that we had at NASA in 2009 regarding the the real study and the way that we could approach looking at disc changes and potentially the etiology of low back pain.

ISS Medical Capabilities

Just to let everyone know, the ISS medical capabilities in comparison to known land-based entities is pretty limited.

We don't have the capabilities that most folks might think that we would have in space, and particularly, it's really no better than Everest base camp ultrasound plays a critical role in what we do in terms of diagnostic imaging, both for research and if we need to use it clinically.

'cause you can't bring an x-ray machine or certainly a very heavy, very large MRI into space.

Nor should you, because ultrasound can do just about everything that those imaging modalities would have at a tremendously less volume and mass impact.

So it's very exciting.

But to give you again you an idea, we're pretty limited in what we can do up there, and therefore we screen and send up very very healthy people in space.

Terrestrial Space-Like Research

Just in terms of a little some of the terrestrial space like research we do, probably unbeknownst to most folks, there is not a microgravity room at NASA where you walk into a room and flip the switch and you float.

You actually have to fly on what we call a parabolic flight aircraft, otherwise known as the vomit comet.

And you actually go to 40,000 feet over the Gulf of Mexico, you dive about 10,000 feet, and when you do that, you get about 20 seconds of weightlessness.

It's a lot of fun.

I do it on an almost like a weekly basis as the medical monitor, but also do research for the guys who actually really do it in the space.

You see a slide there of Michael Fink on his expedition a couple years ago actually doing ultrasound and then sending those images live down to the science center at Mission Control, Scott Chesky from Henry Ford Hospital, along with Doug Hamilton, Ash Sian, and a number of other other Wiley colleagues have pioneered ultrasound in space, and in all areas except for o ob GYN, no pun in there, but the bottom line is they've done tremendous work.

And right now we actually have a a a vivid queue commercial off the shelf ultrasound that's up there to be used both for research and for clinical ca uh uses.

Space-Related Injuries

As far as other things that we deal with, like I said, we have a lot of space related to injuries.

This first the video is Gene Sheeran and Harrison Schmidt on Apollo 17.

And they're traversing across the surface and looks like they're having a great time, and I'm sure they really are.

But the point with that was we actually had a shoulder injury on the moon during one of the Apollo missions.

That was a fairly significant injury, although it didn't impact the mission.

That mission was only two to three days on the moon surface.

If that had been a 30 day or six month mission, there may have been a significant more impact to that crew member.

And ultrasound would've been tremendous assets to have had at that time to actually find out were we dealing with a rotator cuff tear?

Were we deal with some type of impingement?

Was there some type of bural injury or internal impingement?

Anyway, tremendous opportunity for ultrasound to actually play a large role in diagnosing that problem.

Space Suit Related Injuries

Other things that we've had to deal with include the space suit related injuries in the neutral buoyancy lab, which is where we do our space walk training.

It's actually a 40 foot deep pool by a hundred feet long by a hundred 200 feet wide pool at Johnson Space Center.

And the astronauts can simulate as closely as possible in the spacesuit weightlessness as their flight surgeon.

And I get to dive with them, which is actually one of the perks, and it's a lot of fun.

But the problem in that pool is they put hundreds of hours in that spacesuit, and the spacesuit wasn't necessarily designed to actually do those kind of things repetitively.

And we see repetitive use injuries.

This is me in the space suit, showing the difference between two type of heart upper torso designs, the hut the pivot, and the planar.

And they really restrict shoulder motion.

It's not in a natural environment, but the space suit is an incredible engineering device that'll that basically protects the astronaut from the vacuum of space, from radiation, from extremes of heat and cold up to 500 degrees, swings in light and in darkness.

And and yet at the same time, when you have to train in this device in the pool on earth, you can really hurt the shoulders.

And that's what we've seen.

We've seen a number of shoulder injuries that are required surgery.

Part of it is because this heart upper torso with the the scapula superimposed, really restricts the amount of scapular thoracic rotation you can have.

And if you can repetitively try to abuc your shoulder over hundreds of hours, you actually cause wear and tear on the rotator cuff.

One of the things that we try to do to prevent injuries is training in the astronaut gym.

That's our gym in NASA Johnson Space Center, one of the astronauts training.

And even though we do a lot of very good preventative medicine programs, we still see quite a bit of problem in the shoulder.

In particular, this shows you the operational work environment that was more or less designed in the spacesuit and shows you that about 95% of all work was assumed to be within the certain very narrow envelope where you would be kind of internally rotated with your shoulders and flexed.

But as it turns out, the astronaut spend quite a bit of time flexing and ab ducting well over 60 to 90 degrees, along with internally and externally rotating.

And when you do that repetitively for hundreds of hours, you cause wear an tear problems.

So one of the ways we're trying to use ultrasound to actually determine what's happening to the shoulder it's loaded in these abnormal situations, is actually look at something called the Glen the acromial humeral distance.

One of my aerospace residents, Dr. Jennifer Law, has actually got a study now using ultrasound both in loaded and unloaded suited crew members, where you would actually measure this distance and then load it, and then see exactly how it changes.

And then the idea would be not only to prove that the positioning of the heart upper torso on the shoulders actually causing this problem, but also to come up with new design possibilities to reduce the insult to the rotator cuff.

And this is very exciting.

We're doing in collaboration with Dr. Tony Behar at the Detroit Medical Center, as well as Dr. Pam McCulloch at the Methodist Medical Center, as well as all the NASA EVA suit engineers.

It's a very exciting area that we could not do without ultrasound because we can get dynamic impingement views and do these measurements.

Moon and Mars Background

There's a little background on moon Mars, and that was my primary area of work up until 2010.

And the application for ultrasound, again, if God forbid you had a problem on the International Space Station that required medical of evacuation provided you could survive, you'd get back to Earth in about six to 24 hours.

However, if you're going to the moon and you had a problem on the moon, it takes 6.5 to nine days to return.

And if it was a Mars problem, you wouldn't be coming back for anything.

So you need to have a robust, reliable very effective imaging capability for the the conditions that we think could be possible in those environments.

And ultrasound certainly meets that requirement.

Again, surgery in space is not something you want to do, so you wanna make sure you have your diagnosis right and that you can do procedures that don't require really invasive techniques and certainly needed guide aspirations and or injections.

Under ultrasound guidance is a fantastic application.

Potential Conditions on Long Missions

Some of the conditions that we believe are reasonable based on extensive analysis for probabilities based on our population and the type of mission they would do are as follows.

We number one and foremost and we see orthopedic and muo skeletal problems.

There are a number of different rashes.

We get foreign bodies in the eyes and different things, the circadian disruptions, et cetera et cetera, are the most common things.

Again, even though there are immune changes in hematologic changes, we haven't had tremendous infections, but that's also an area that we would have to look into.

Certainly minor lacerations, wounds, burns would be potential, although we've not really had any serious burns or anything like that.

Toxic exposure is always a a concern as well as acute radiation sickness, although we take extreme measures to really try to prevent any of these problems.

And to date, after 50 years of space light, we've been pretty good at preventing any real problems in space with our astronauts.

And of course, chronic exposures, if you've been in space for a long time, are also concerned, but that's really what the flights are in NASA's thinking about.

And you can see how ultrasound is potentially very beneficial in some of these conditions that we expect to see.

Soldier Medical Care

Gonna change gears here a little bit and just talk about soldier medical care and what I did as a flight surgeon in Iraq last year.

And also having worked with a lot of my colleagues and using ultrasound in an operational military environment, and how useful it was, had really been probably the number one condition that I saw in any given day with the soldiers or musculal conditions, rotator cuff injuries, bursitis, knee effusions for whatever reason, traumatic or non-traumatic, ultrasound was a tremendous asset here.

It was just doing a subacromial injection for a soldier.

These soldiers besides being extraordinarily dedicated, are probably their own worst enemy, in that they will work through tremendous pain to get their job done.

And as opposed to kind of the state side application of a very conservative measure of practicing orthopedics, where you would do conservative therapy consisting of anti-inflammatories, rehabilitation and or physical therapy, and time to get people back out to do their job, to make sure that they're ready for the fight, I typically would inject very quickly.

But having ultrasound at my bedside for all these conditions was extremely helpful to try to rule out more serious conditions where I might have to medevac a soldier out to a field facility where we could actually do an an MRI.

And for us in Iraq, that nearest facility was gonna be in launch Stool Germany, which basically was a major medical evacuation.

So I wanted to make sure I had my diagnosis right.

And with the use of ultrasound, I was able to do that very easily in most cases.

And again, here's a knee ultrasound.

Army Research on Cervical Spine

Now, one of the research applications for ultrasound that we're proposing to do at the US Army Amic Research Lab is to actually look at the kinematics of this the functional spinal unit in the cervical spine.

I've got a slide here showing a soldier on the left.

It's actually our our door gunner out the left side of a black hawk.

And you just show how really crummy his ergonomics are, and he's sitting in a seat that doesn't attenuate load or vibration whatsoever.

So for six hours a day, every day, he's being exposed to that that type of environment.

And it's not only males.

We do have a few female crew chiefs.

The majority of them are in their mid to late twenties, some are early thirties, and we even have some crew chiefs who are in their late fifties and early sixties, tremendous war fighters, amazingly folks, but unfortunately, they're subjecting their spine to loads and vibrations that are causing premature wear and tear.

This is a picture on the right of my helmet both of the night vision goggles and the helmet itself, which weighed probably six to seven pounds.

Now in the army, we don't pull out of g in helicopters unless we're in trouble.

But we're exposed to 17.2 hertz vibration continuously.

And our missions were five to six hours a day after day after day after day.

And that way especially for flying weight night missions was very bothersome to the neck.

Frequently would get back from night missions with neck pain, certainly low back pain.

And that was a pr probably the most common problem that I saw with my pilots and crew chiefs.

Very interesting in terms of the operational research cap opportunities with ultrasound, a couple articles that come out over the years proposing using ultrasound to look at the musculo ligamentous structures in the C spine.

And one of my graduate students actually had Dr. Dan Buckland was doing his MD PhD at Harvard, MIT.

And we had talked about how we have spine back and disc problems and astronauts, and that there might be an application for actually using ultrasound to actually look at the functional spinal unit.

Actually, part of his dissertation proposed actually looking at live models after he did static and pig studies actually loading, distracting, and compressing the spine, and then developing a method whereby you could do this reliably and it could be validated.

And sure enough, he demonstrated consistently that cervical ultrasound ultrasound particularly looking at two vertebral bodies in in evaluating the kinematics that those vertebral bodies can elucidate what the actual changes are going at the inner vertebral disc is very promising.

He has a study along with Dr. Brian Schneider at Beth Israel doing this in a simulated environment.

And then I hope to actually take this to a live environment and then potentially Afghanistan next year to do this both pre-flight, in-flight and then post-flight and try to quantitate both normal and abnormal and army aviators and crew chiefs, which I think will provide a lot of insight into what's actually happening at the intervertebral disc level with prolonged loading and vibration environments.

Conclusion

So that's what I do, and that's how I use ultrasound as an adjunct to my clinical evaluation.

And we're really blessed to have that capability and certainly the the folks at Sono World providing a continuing resource of expertise and skill building.

And I think that the the future's very bright for what we do and very much look forward to future moon lunar mission and potentially Mars mission where we can use that technology for unlimited capabilities.

Thank you.