For 72 straight hours, the research volunteer lay in a mattress at UT Southwestern, the monotony damaged solely at night time when researchers positioned his decrease physique in a sealed, vacuum-equipped sleeping bag to drag down physique fluids that naturally flowed into his head whereas supine.
New analysis revealed in JAMA Ophthalmology reveals that by suctioning these fluids and unloading mind strain, the specifically designed sleeping bag might stop imaginative and prescient issues astronauts endure in space, the place fluids float into the top and frequently push and reshape the again of the eyeball.
The phenomenon has vexed scientists for greater than a decade and stays one of many largest well being dilemmas of human space exploration. But the findings from UT Southwestern – which NASA enlisted to hunt solutions to astronauts’ imaginative and prescient issues – recommend the high-tech sacks might present an answer.
Notably, researchers discovered that whereas simply three days of mendacity flat induced sufficient strain to barely alter the eyeball’s form, no such change occurred when the suction expertise was used.
“We don’t know how bad the effects might be on a longer flight, like a two-year Mars operation,” stated Benjamin Levine, M.D., a UT Southwestern heart specialist who helps NASA tackle the well being dangers of mind strain and irregular blood stream in space. “It would be a disaster if astronauts had such severe impairments that they couldn’t see what they’re doing and it compromised the mission.”
NASA hopes the sleeping bag can tackle a dysfunction referred to as spaceflight-associated neuro-ocular syndrome, or SANS. The situation is characterised by progressive flattening of the eyeball, swelling of the optic nerve, and imaginative and prescient impairment.
Previous research by UT Southwestern and the Institute for Exercise and Environmental Medicine at Texas Health Presbyterian Hospital Dallas confirmed SANS is probably going brought on by the fixed strain that physique fluids apply to the mind.
SANS isn’t an issue on Earth, the place gravity pulls fluids down into the physique every time an individual will get away from bed. In space, the shortage of gravity prevents this day by day unloading course of, permitting greater than half a gallon of physique fluids to assemble within the head and apply strain to the eyeball.
NASA has documented imaginative and prescient issues in additional than half of the astronauts who served for no less than six months on the International Space Station. Some turned farsighted, had issue studying, and typically wanted crewmates to help in experiments.
“You can’t stand up in space to unload the pressure. That’s the problem,” stated Michael Stenger, Ph.D., a scientist with NASA’s Human Health Countermeasures Element.
Perhaps the perfect treatment to date has been using particular space glasses with adjustable lenses that right astronauts’ altering imaginative and prescient aboard the space station. But this technique does little to alleviate issues concerning the long-term results on the eyeball, nor the potential cardiovascular issues that Dr. Levine’s workforce is uncovering.
A 2018 research, for example, confirmed that spending six months in zero gravity might enhance the chances of creating a standard coronary heart arrhythmia referred to as atrial fibrillation. This situation can result in blood clots, coronary heart assaults or stroke.
“And it’s certainly possible there are other effects of brain pressure we haven’t documented yet,” Dr. Levine stated. “The astronauts report something they call the ‘space stupids.’ They make more mistakes than they think they should. Whether that has anything to do with the inability to lower the pressure, we don’t know.”
Although some results of SANS seem non permanent – imaginative and prescient returns to regular shortly after astronauts return to Earth – Dr. Stenger stated UT Southwestern’s analysis is significant to the manned Mars flight that NASA hopes to launch within the 2030s. The sleeping bag expertise, specifically, may tackle each the mind and coronary heart points.
“What are the long-term health consequences (of SANS)?” Dr. Stenger stated. “There’s a large team on the ground working to counteract a lot of these risks.”
Measuring mind strain
The sleeping bag prototype is the end result of a number of phases of analysis performed by UT Southwestern to assist NASA higher perceive the dysfunction, together with a 2017 research that offered compelling proof that fixed strain might certainly contribute to SANS.
To check his concept on mind strain, Dr. Levine recruited most cancers survivors from throughout the nation who nonetheless had ports on their heads the place they’d acquired chemotherapy. These ports supplied researchers uncommon entry to measure strain immediately within the mind.
The volunteers every went on a zero-gravity airplane flight into the higher ambiance the place their physique fluids floated upward. A neurosurgeon from UT Southwestern’s Peter O’Donnell Jr. Brain Institute measured the mind strain by inserting particular tools into the port.
“It was hard,” recalled Wendy Hancock, a leukemia survivor from Philadelphia who agreed to go on greater than three dozen up-and-down maneuvers into zero gravity. “But NASA is awesome, so, heck yeah, I was going to jump at the chance to help. … I did it for the astronauts.”
The ensuing research confirmed that mind strain in an individual who lies down on Earth is definitely increased than in space. However, on Earth the strain is unloaded when the particular person stands and gravity pulls the fluids down. Space offers no such aid for astronauts.
A brand new treatment
With this significant perception, Dr. Levine’s workforce began working with the outside tools retailer REI to develop a high-tech sleeping bag that may very well be utilized by astronauts every night time to unload strain within the mind. Although related decrease physique unfavorable strain expertise has been used for many years to keep up muscle and bone mass in space, earlier prototypes weren’t designed for a lot of hours of use or examined as an antidote for SANS.
The bag has a stable body – aptly formed like a space capsule – and is designed to suit over an individual from the waist down.
About a dozen individuals volunteered to check the expertise, together with Dr. Leidner, an inner medication hospitalist in San Antonio who’s taken with pursuing a profession in aerospace medication.
He made two visits – three days every – to a UT Southwestern analysis room the place he lay in mattress. Only in the course of the second go to was he positioned within the sleeping bag for eight hours every night time. Researchers in contrast modifications within the mind after every stint.
“Being productive has gone out the window,” he joked, declaring the awkwardness of typing on his laptop computer whereas mendacity flat. “But it’s an experience I could tell my kid one day if it helps humans land on Mars.”
Several questions should be answered earlier than NASA brings the expertise on the space station, together with the optimum period of time astronauts ought to spend within the sleeping bag every day.
But Dr. Levine stated his newest findings point out SANS hopefully will not be a well being threat by the point the space company is able to launch to the Red Planet.
“This is perhaps one of the most mission-critical medical issues that has been discovered in the last decade for the space program,” Dr. Levine stated. “I’m thankful for the volunteers who are helping us understand, and hopefully, fix the problem.”
Dr. Levine has researched the results of space journey because the early Nineteen Nineties, when he implanted the primary catheter to observe the guts strain of an astronaut in space. Since then, he has labored with NASA on varied tasks and advises its flight surgeons on cardiovascular medical points. NASA not too long ago awarded him $3.8 million in direct and oblique funding over 13 years to review the results of space journey on the guts.
Other key members of Dr. Levine’s workforce included Christopher Hearon, Ph.D., first creator on the JAMA research and Assistant Instructor within the Department of Applied Clinical Research at UT Southwestern; and Tony Whitworth, M.D., a neurosurgeon from the O’Donnell Brain Institute who measured sufferers’ mind strain in zero gravity.
Dr. Levine is Professor of Internal Medicine and Director of the Institute for Exercise and Environmental Medicine at Texas Health Presbyterian Hospital Dallas, a partnership between UT Southwestern and Texas Health Resources. He holds the Distinguished Professorship in Exercise Sciences at UT Southwestern.