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For other articles and previous issues click here. June 7, 2004
To Infinity and Beyond What happens when an astronaut aboard the International Space Station (ISS), 240 miles above the Earth, has persistent pain in his side? Far from an imaging machine and a radiologist, how can an accurate diagnosis be made and proper treatment started? A new ultrasound training program for astronauts hopes to address these problems and show the value of ultrasound as an imaging device in remote locations on Earth and beyond. Ultrasound has long been used to diagnose a variety of medical conditions—from problem pregnancies to diseases such as gallstones and kidney stones. Considered fast and safe, it can also be performed by astronauts who have received modest sonography training. Several years ago, a scientific advisory panel to NASA suggested that ultrasound might be the diagnostic tool needed for medical emergencies that occur on space missions, says Roger Crouch, PhD, senior scientist for the ISS. The idea was to transmit high-quality images obtained from ultrasound via satellite to trained medical personnel on Earth who could then suggest appropriate action or treatment. The images could be transmitted in real time or with a slight delay depending on exactly where in orbit the astronauts were. The first thing NASA had to determine was whether or not nonmedical personnel (most astronauts are not physicians) could be trained to use a transducer and acquire ultrasound images. Scott A. Dulchavsky, MD, PhD, chair of the department of surgery at Henry Ford Hospital in Detroit, was chosen to lead a team of NASA scientists in determining the appropriate training. The team developed an intense educational program that includes two hours of hands-on training in a classroom setting and an interactive CD-ROM that has computer-generated and real ultrasound images. Astronauts in need of a refresher course once they arrive in space can view the hour-long CD on board the space station. On average, sonographers have 300 to 500 hours of training; however, Dulchavsky says NASA sonographers were “blown away” when they saw the abbreviated training program. ISS Science Officer Peggy Whitson served as an ultrasound “guinea pig” during her 2002 stay aboard the space station. Crouch says Whitson was impressed that she was able to image her heart, carotid artery, kidney, and bladder with guidance from the ground team—even with a slight delay in video image transferrence. Modifications for Space An increased amount of information storage and redundancies was built in “so it’s harder to break,” Dulchavsky says, adding with a laugh that sending a repairman to space would not be cost-efficient. Cost was a factor when choosing which imaging modality could go to space. Ultrasound machines are less expensive than x-ray or CT machines. “A portable ultrasound device with bells and whistles is about $30,000,” Dulchavsky says. The fact that ultrasound images are real-time and there is no film to develop was another benefit. Dulchavsky says nonmedical personnel were able to transmit quality images to trained medical personnel on Earth. “They did side-by-side comparisons of the images obtained by the astronaut crew sent through space with those done by experts on the ground, and they were virtually indistinguishable. They were spectacular.” The next step, Crouch says, is for NASA to build a database of ultrasound scans on its astronauts for use as a baseline while they are in orbit. If a problem arises, medical experts can compare the image taken on Earth with that transmitted from space. “They could take the data from the live person, feed it into the computer that has the database, look at the variances between the old and new data, and make a diagnosis.” Fortunately, Crouch adds, “we have not used ultrasound in space for any actual injury diagnosis because we haven’t had any injuries that required it.” Crouch believes ultrasound will eventually play a role in space research. One area of research already underway is how space travel affects an astronaut’s bone density. Currently, bone density measurements are taken on astronauts before they launch and when they return. If ultrasound aboard the space shuttle proves capable of measuring bone density, it could be used by the astronauts to take periodic bone density measurements while in flight. “It would be nice to have that intermediate data,” Crouch says. NASA also aims to have ultrasound available when it launches the first manned mission to Mars sometime after 2030, says Crouch. Mars is approximately 42 million miles from Earth at its nearest point and more than 135 million miles at its farthest. It takes approximately 22 minutes for a message to reach Earth if it is traveling at the speed of light. “That would make real-time conversation or interaction almost impossible,” Crouch says. “We want to develop autonomous medical capabilities in the spacecraft, and we see ultrasound as a very promising diagnostic tool in establishing this capability.” New Earthly Applications Dulchavsky says ultrasound is routinely used in trauma centers to diagnose abdominal injuries, but it shows promise for many other conditions—from broken bones to infections. Dulchavsky, a fan of the Detroit Red Wings, has already made a connection between the ultrasound techniques developed for NASA and the National Hockey League teams. While attending a home game at the Joe Louis Arena, he wondered what the team did when a player was injured. He suggested that the team place a portable ultrasound machine in its locker room. That way, when a player was injured, the team’s doctor could use the machine to transmit images to Henry Ford Hospital. “Then we could read the images and give him the same information we would give the astronaut crew,” Dulchavsky says. He thought that scenario would be faster and less costly than transporting the injured player to the hospital for an x-ray, CT, or MRI, as is usual protocol. It would also make it easier on the team and player because they would know immediately whether the injury was serious enough for the player to leave the ice and could be useful when the team travels. The Red Wings’ trainer took the same condensed
course in obtaining ultrasound images as the astronauts. A trial
demonstrated that ultrasound can be used to enhance athletic medical
care with minimal training and cost, Dulchavsky says. Stephen Smith, MD, of the department of surgery at the University of Kansas School of Medicine-Wichita, was asked to validate the NASA ultrasound project because of his long history with ultrasound in trauma and surgical settings. He says two aspects of the NASA ultrasound research project are exciting: One is that people with little medical background can be trained to perform targeted ultrasound exams in just a few hours, and the other is that ultrasound could prove useful in many more medical conditions and situations. “If you can do this 300 miles above the Earth, you definitely can do it in western Kansas,” he says. “Fast” Exam The FAST exam looks at six areas: the pericardial space for cardiac tamponade, a life-threatening condition caused by fluid under pressure around the heart; Morrison’s pouch; the spleeno-renal recess; the pelvis, to look for blood in the abdomen; and the right and left chest areas, to look for pneumo thorax, a collapsed lung. Smith says the exam is straightforward and does not require 1,500 hours of experience to perform. If paramedics can be trained to do FAST exams with the Dulchavsky team’s methods, it could mean saving the lives of more trauma victims, Smith says. Some initial training of paramedics has already been completed. “Within the next couple of months, we hope to start training flight crews to go out independently with an ultrasound machine, perform the studies, and record the results,” Smith says. The results of the exams done by paramedics in the field will be compared with the results of the exams done when the patient arrives in the trauma center. Smith hopes to train roughly 30 flight crews—nurses and paramedics—based in the Wichita area. The second study involves obtaining ultrasound images
either at the site of an accident (or on the battlefield) or in
a helicopter as a patient is transported to the nearest trauma center.
The study will likely utilize satellite technology so images can
be transmitted to experts while the patient is in flight. “However,
we’re still trying to work out the details, including the
grants to get this up and running,” Smith says. The goal is to see whether it is helpful to have the diagnostic studies done in flight rather than waiting until the patient arrives at the trauma center. Saving Time Additionally, he says, if you found a patient had blood in his or her abdomen, “you could mobilize your staff and get ready to take that patient to the OR upon arrival.” Smith says previous studies comparing prehospital diagnosis with diagnosis at trauma centers found that the earlier diagnosis did not make too much of a difference. However, he says, those studies involved urban settings where the trauma center might have been minutes away. He believes earlier diagnosis could be extremely useful in rural or remote areas where the nearest trauma center may be 200 miles away. It seems obvious that ultrasound in flight “would have a higher chance of being applicable in a rural or remote setting than it does in an urban setting,” he says. Dulchavsky says that while small, portable ultrasound machines may cost tens of thousands of dollars, they could save hospitals money if they preclude the need for costly airborne evacuations. — Beth W. Orenstein is a freelance health writer and regular contributor to Radiology Today. |
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