Space Medicine and the Deconditioned Astronaut

Col(s) Kristen Silvia is a board certified Emergency Medicine Physician, Flight Surgeon and currently Chief of Bioastronautics at Detachment 3, Human Space Flight Support Office, Patrick Space Force Base, Florida. She leads the DoD’s contingency medical operations for NASA and U.S. Space Command in support of U.S. crewed space flight programs. She also directs training of space medicine to all DoD forces for worldwide astronaut rescue/recovery and nominal/contingency landing site support. Prior to her current position, she trained the Air Force’s Pararescueman (PJs) in all aspects of combat trauma and critical care as the Medical Director for the Pararescue & Combat Rescue Officer School.

For access to the slides and to view the whole lecture, visit:
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Transcript

Kristen Silvia: 1:02

Hi, I'm Lieutenant Colonel Kristen Sylvia, Chief of bio astronautics at the 45th operations group detachment three down at Patrick Space Force Base, part of the human spaceflight support office. I'm going to be talking to you today about space physiology and the decondition astronaut. Just a little bit about my background. I am an emergency medicine physician graduated from residency in 2006, Stan and San Antonio. The objectives we're going to cover today include understanding the DoD HSFs mission, understanding the effects of microgravity on the human body and the different organ systems, recognizing some normal signs and symptoms that are associated with spaceflight. Some treatment considerations that are unique to patients exposed to spaceflight, and a few historical spaceflight medical events. The DoD human spaceflight support office or detachment three is the office of primary responsibility to carry out Commander US Space comm assigned responsibilities for HSFs operations. Our office was established in 1959 was originally called the Department of Defense, Mercury support, and then DoD man spaceflight support office or DDMs. Our name was changed to human spaceflight support, but our mission has remained the same. We currently have about 30 Personnel assigned to specialize in rescue, recovery and retrieval. They include US Navy surface warfare and salvage divers, Air Force fixed and rotary wing rescue specialists, guardian angels and cluding. Pair rescue and combat rescue officers fire rescue that our hazmat experts see 17 or US transcom experts as well as aerospace and space medicine physicians. The picture on the bottom right, shows demo mission two upon landing, that is this first SpaceX capsule that was manned that went up with two astronauts. The physician that you see on the left of that picture is a Neil menen. He is a SpaceX medical director and also my ima. We support three programs with four capsules including the Soyuz, which is really a Russian ISS taxi service, the US pays about $84 million per seat on the Soyuz. The support we offer is a and Seacat only upon landing. The Commercial Crew Program consists of both SpaceX and Boeing and this is a commercial ISS taxi service. The support we offer is contingency rescue as well as meta back upon launch. The Artemis program is NASA's Deep Space Program going to the moon and eventually Mars. Our support is everything from nominal recovery, contingency rescue, capsule retrieval and salvage as well as meta back. So we're currently focused on rescue with commercial crew program but Artemis is going to be starting up soon. We hopefully will have our first launch this year and our first crewed mission will be either this year or next. When we stand up our task force 45. We are in multiple locations throughout the United States, including teams out at Joint Base Pearl her Joint Base Pearl Harbor Hickam Joint Base Charleston, as well as Patrick space for split base. At Patrick, we stand up our support operation center. And we also have a member at Johnson Space Center in Houston that works in Mission Control. We also have members in Colorado and California. When we were looking at medical training, supplies and equipment that were needed for a mission, we use a medical model to identify possible metal click current medical conditions and treatments as well as protocols. This is a sample emergency medical conditions model that we use to ensure that we considered as many possible events and associated medical and traumatic conditions that we could expect to see. When you break out the spacecraft failure. We take each system or injury and further break that down to look at what response or treatment can we reasonably provide. Knowing that our pair rescue teams will be out in the open ocean. And not on this list is blood. We do carry two units of low titer or whole blood per astronaut for both launch and landing sort of picture of our medical assemblage. This is for one location for Charleston and hicom. We have for astronaut March bags, which is really a 60 minute bag it has everything they'll need for the first 60 minutes of care. They'll have blood boxes with a two units each backwards oh two kits, prolonged field care bags and those also contain our controlled medications as well as our defibrillator and our events. We used to save two events as well as the C Mac. And for monitoring we use the Athena which is a wireless monitor that does heart rate blood pressure o to co2 as well as three lead EKG. Most Athenas can be transmitted directly to a smartphone or tablet. We do carry supplies and medications for for critically ill or injured crew members for up to 72 hours and includes for events and all the medications that we would need for sedation for that time. At Patrick. We also have advanced life support kits which encloses all empties, and a couple other things in the halos. This is a picture of all of our rescue equipment at Cape Canaveral Space Station. This was before we moved our equipment forward to Hawaii and Charleston. And it consists of hard ducks and arcs, also known as jet skis. All of it is packed for air drop with a parachute attached. Our survival bundles are among this as well. All right, on to the human response to spaceflight. So astronauts experience a spectrum of adaptations in flight and post flight, collectively known as space Adaptation Syndrome. The neuro vestibular system provides our sense of balance position in motion, but the inputs are come to us via gravity. And once we're in a weightless environment, those inputs are immediately and radically altered. These lead to essential sensory conflict, we do still have rotational motion because that works independent from gravity. They do eventually adapt to a position sense and motion, but the initial adaptation can cause some spatial space motion sickness. Upon returning to Earth, they're still adapted to microgravity, and that causes the reactivation syndrome. So about 70% of all crew members are affected by space, space motion sickness, and about 10 cases are 10% of cases are severe or debilitating symptoms or anything from vertigo unstable gait and nausea and vomiting which can be very difficult to control initially. Time course the onset is anywhere from main engine cutoff. Mikko which is a few minutes after liftoff up to 24 hours, pick up symptoms is anywhere from 24 to 48 hours and the symptoms usually resolve at 72 to 96 hours. Medication pre and pre flight training are the best treatments for this. Once they return to Earth, almost all crew members are affected to some degree by readapt patient syndrome. They may have difficulty walking around corners feeling that they're falling to the side and the earth is coming up to towards them and feeling that they're pushing the ground away as opposed to them walking. They're having to push the earth away. Some of the symptoms include vertigo with unidirectional nystagmus unstable gait and severe nausea and vomiting. This can last anywhere from landing up to 72 hours after Sometimes it lasts longer than that. Treatment is avoiding rapid head movements and progressive increase in activity and any of the combination of medications. Our initial dose of Phenergan is about half of the normal dose. This is a video of an astronaut 24 hours after landing after being on the ISS for six months and you can see he is requiring assistance with ambulation and it's very unsteady. And if we can go forward from this video. There we go. Alright, this is a basic graphic of our cardiovascular system. A is what we look like on earth the gravity is exerting a downward force, which sets up a vertical hydrostatic gradient. When we're standing some of this excess fluid resides in the vessels and tissues of the legs. B we have initially once in space, we have a loss of the hydrostatic radiant, the fluid redistributes to the head and chest causing some congestion, almost feeling like they have sinus infection or seasonal allergies. This increase in cardiac return it senses the overload of circulating blood volume. And C is once the body starts adjusting by reducing the plasma volume 12 to 15%. During early flight, with a loss of one to two liters, whole body volume normalizes later in flight. And then there's also a total red blood cell deregulation downward to maintain the normal concentration or a relative anemia. D is once we're back on Earth and gravity again pulls the fluid downwards. There's a low peripheral resistance because that was downregulated during flight, and there is a relative intravascular deficit. Now they're about two to three liters down in both circulating fluid and red blood cells. All crew members are affected to some degree, and the signs and symptoms would be the same as you would expect in somebody with severe dehydration, including orthostatic intolerance and syncope, decreased blood pressure, increased heart rate, weakness, malaise, nausea, and they also have increased heat stress due to their pressure suit. And this can go anywhere from landing up to a few days. The treatment is pre landing an oral fluid and salt loading protocol. This regains about 6% of their plasma volume. They also were lower extremity tension garments and are in a reclined position in the space capsule post landing, they're giving oral fluids if they tolerate them or IV bolus and the nausea is treated, they're also rest will help and with any kind of trauma, they may need blood sooner than stage three shock. In 2018, there was a cohort study of 11 ISS crew members looking at internal jugular blood flow, and they found that six of these crew members demonstrated stagnant or retro delayed retrograde flow in the IJ on approximately flight day 50 out of 130 to one of these crew members developed a completely occlusive clot in the IJ during spaceflight. This is the first known blood cotton microgravity, and although the etiology is unknown, they believe it may be from the harness it's worn to keep the crew member on the treadmill when they're exercising. There is 40 days of anticoagulant on ISS which this astronaut was started on, there is no reversal on the ISS. And oral medication was sent with a resupply and that was held launch bay launch day minus four. Whereas if they're radical risk of peas and strokes, we have not seen those on any astronauts up to this point, but it's certainly a possibility. The weightless environment also causes a relentless atrophy of muscle of bone and muscle tissue. The bones don't have to carry weight and the muscles don't have to work against the polar gravity, the bone can atrophy 1.3 to 2% a month, decrease in bone density and most of this is mitigated by exercise, there is an increased risk of kidney stones secondary to calcium excretion. But that risk is greatest in the six to 12 month post planning period. The muscles can atrophy 10 to 20% on short missions, and that may be as high as 50% on longer missions. Without Exercise, peak power decreases by 30 to 35%. There's also a two to six centimeter increase in spinal length. And all of this affects mostly the weight bearing regions including the lumbar spine, pelvic girdle and the legs. And the countermeasures on the ISS are good but not a complete solution. All crew members are affected to some degree. And we see weakness fatigue and poor coordination also impaired physical ability unable to extricate themselves from the capsule. There's a risk of long bone fractures and herniated disk or spine injuries as well as pelvic fractures. timecourse symptoms are usually worse early on and improve over time and they require assisted ambulation and rest and a 40 feet 45 Day guided rehab program. Urinary retention has occurred both during spaceflight and on landing. Some of the factors are obstructive, which females are four times more likely than males and spaceflight to have obstructive urinary retention whereas males are more likely than females on landing day. If they have retention their risk of UTIs is increased by 25 times treatment of courses urinary catheter, which also will increase our risk of UTI as well. The ocular system is affected something called spaceflight associated neuro ocular cysts syndrome or Sans, they found that 20 to 31, astronauts developed some or all of these findings, either during or following a six month spaceflight, including optic disc edema, cotton wool spots, a decrease in their near vision, coronal folds, optic nerve sheath dissension and kinking. As well as globe flattening, they have found that they have an increase in CSF pressure post flight as well. They believe it's due to the fluid shifting towards the head, which is causing the increase intracranial pressure, and that's transmitted to the optic nerve to the globe. As you see the top MRI picture, you can see the kinking of the optic nerve. And the bottom pictures show the globe flattening postflight compared to the preflight MRI, about 60% of the crew members have at least one sign of Sans. And the symptom that they're looking for is a dear decrease in near vision. And this can last from the time they're in space up two years post landing, and there is no treatment in the field. So in summary, almost every organ system is affected by microgravity. There's a couple that we didn't discuss. psychologic is one of them. But these astronauts and crew members are rigorously selected and tested and trained and they train with the same people. But they are also in a closed environment. And their risk of skin infections and other infections is increased as well. Not every astronaut is affected the same way. This is a Soyuz landing and Kazakhstan. So our first crew member that comes out is a Russian cosmonaut. And as you can see, he's slightly ashen and is not turning his head is not helping at all with his extrication and does not look like he is having a good day. And hopefully we can get our video going again. All right, well, we can't but we'll go on to some historical medical events in spaceflight. First one we'll talk about as a pad of work for so use t 10. One, this one the rocket caught fire on the pad. The launch escape system fired about two seconds before the rocket exploded. The touchdown of the capsule was about two and a half miles downrange and the crew members were bruised and but otherwise were in good health and they did not require any medical attention. Once they were greeted by recovery crews they asked for both cigarettes and vodka. The asset aboard of the challenger is pretty well known to most of us. It was caused by a failure of an O ring seal on a solid rocket booster. And the breakup of the vehicle began at takeoff plus 73 seconds at an altitude of about 48,000 feet, or about 18 miles downrange the cabin hit the surface about two minutes and 45 seconds after the breakup. And they think that the crew was still alive upon impact. Was it a sense abort for a Soyuz 18 A and this was takeoff plus 295 seconds due to a separation failure, causing the capsule to deviate off course the cosmonauts experience up to 21 G's and they landed successfully about 1000 miles downrange. They landed on this snow covered slope and the capsule began to roll downwards towards a cliff and the parachute snagged on some vegetation and kept them from rolling off the cliff. They were in chest deep snow with a temperature of about 19 degrees Fahrenheit. And because of the snow and the high altitude, they were not rescued for about 24 hours. And the ballistic reentry of Gemini. So this flight was aborted after six orbits due to tumbling. It splashed down about 500 miles east of Okinawa. The PJ's that are pictured in the bottom right are Glenmore Eldridge, Neil and Larry Hewitt. And those PJ's jumped to the capsule that we see on that top picture. They were recovered by the USS Leonard Mason within three hours and all five of them suffered seasickness and they were on The Ed Sullivan Show after. I know most of you probably don't know what the Ed Sullivan Show is, but it was a very popular talk show way back in the day. There was a rapid decompression of Soyuz 11 And this was a nominal or normal reentry of the capsule landed safely under canopy and there was no signs of damage. When the recovery teams opened up the capsule they found all men in their seats, motionless dark blue patches on their faces, and trails of blood from their noses and ears. It seems that a rare event was jerked, opened during the separation of the orbital and descent modules and that caused a rapid decompression at an altitude of about 104 miles or 55,000 feet. death occurred in less than two minutes. And after that pressurized suits were worn during launch and landing. There is videos out on the web that show the rescue to the rescue group rescue crews attempting CPR on those cosmonauts after pulling them from the capsule. Alright, and last one we'll go over is other landing medical events. There was a couple of cases of pneumothorax on landing one was a hard landing on its side, where the crew member had right sided chest pain and some shortness of breath and increasing dyspnea. He went to surgery for a ruptured diaphragm and a pneumothorax. There was also a couple of back injuries on landing one was a hard landing, about 21 G's and a seat failure caused that injury. There was also a spinal compression on landing during a ballistic reentry. I'm going to skip the last couple and our summary. So we went over the HSFs mission and some space physiology as well as a few of the historical medical events in spaceflight history, which is why we do what we do. And this is a picture of one of the pair rescue berets that is floating on the ISS. This is a the Kupala with this earth on the background. This was for one of the pair rescue men after 30 years when he retired last year. These are some of my references. They're certainly more of them out there. But the second to the bottom. Michael Barrett is a current astronaut, also a physician. He wrote the book on the principles of clinical medicines for spaceflight, which is where most of this information comes from. And also the very top one the fundamentals of space medicine. I am going to be available for any questions that you may have. And thank you for listening