Providing medical care in under-served or remote areas is difficult due to limitations of skilled personnel, a lack of equipment, and environmental challenges; these same constraints are problematic for the current space program. NASA is investigating a number of novel techniques to enhance medical care capabilities in the current and future space program including just-in-time educational programs, intuitive medical devices, and expanded uses for point of care ultrasound [14–17].
Ultrasound is currently used in most trauma centers as the first line diagnostic procedure in patients with abdominal trauma and has been verified as accurate and sensitive even when performed by non-radiologists . Advances in ultrasound technology have led investigators to suggest expanded diagnostic applications of ultrasound to evaluate the thorax, long bones and joints, soft tissues including odontogenic and sinus infections and evaluation of foreign bodies or trauma to the eye [8, 14].
Evidence-based trials have demonstrated the accuracy of ultrasound in a wide variety of aerospace relevant clinical conditions when performed and interpreted by experts. Recent International Space Station experiments have shown that just-in-time trained astronaut crew-members, equipped with on-board proficiency enhancement, can acquire complex, diagnostic quality ultrasound images . The expansion of just-in-time ultrasound training to autonomous ultrasound operation, coupled with enhanced on-site interpretative capabilities, would significantly expand the medical diagnostic capabilities and would provide significant, clinically relevant advances in space medical capabilities with profound Earth-based ramifications.
Significant musculoskeletal degeneration occurs during long duration spaceflight. Mission specific requirements which necessitate exertion after a prolonged microgravity exposure may heighten the risk of injury during exploratory missions in the future. Significant reductions in muscle mass and strength occur during long duration spaceflight despite aggressive exercise regimens [19, 20]. The ability to longitudinally quantify decrements in muscular mass/strength during spaceflight would provide a reliable predictor to guide anticipated work requirements and scheduling to maximize crewmember performance. Several investigators have demonstrated that ultrasound can accurately identify acute bony and ligamentous injury; however, these reports do not involve large study cohorts [2–4, 14, 21, 22]. Ultrasound can also be used to determine the degree of healing of bone and degeneration. Orthopedic ultrasound appears to be a promising area of application which is currently being investigated by NASA scientists.
This is the first report comparing remote expert guidance and autonomously performed ultrasound in an austere environment. The experiments were performed in the field at Resolute Bay, Canada, high in the Arctic Circle. This environment was chosen due to its extremely remote location, and lack of electricity/connectivity as an extreme test of the point of care capabilities of portable ultrasound. A battery-powered, environmentally rugged, high fidelity ultrasound device functioned well for the imaging requirements of this trial. Phone and video-streaming connectivity was established for the remote guidance section of the trial via satellite uplink without difficulty, despite being at the extreme edge of satellite coverage. Remote connectivity was used sparingly due to the very high cost of satellite bandwidth.
Volunteer operators, without prior ultrasound experience, were able to complete ultrasound examinations with or without real-time guidance. The autonomous scans which were successfully completed suggest that targeted training algorithms may allow minimally trained operators to perform diagnostic examinations with a minimum, or no connectivity. The majority of examinations were completed successfully and yielded diagnostic quality images. Further attention to training or additional materials may be required for challenging anatomic regions such as the elbow.
This study had several limitations which should be addressed in future, more comprehensive examinations. The ultrasound examinations were conducted in asymptomatic subjects, therefore, the ability of the operator or the remote expert to diagnose pathologic conditions was not established for this protocol. This was a preliminary report due to significant environmental and financial constraints. The number of operators and subjects was not large due to challenges in recruitment due to the small population and limited time spent in the Arctic Circle. The average cost per satellite session was approximately $150 due to the large data file transmission characteristics of video transfer. The environment posed significant challenges including temperature (which reduced battery efficiency and exposed examination times), location (the extreme northern location was at the uppermost limit of satellite coverage mandating careful satellite antennae positioning), and resource constraints (external power was not always available).
This report suggests that point of care ultrasound may provide a diagnostic tool for remote or under-served regions where skilled health care professionals are scarce. Inexperienced operators were capable of performing focused ultrasound examinations and achieving targeted, diagnostic quality images autonomously or with real-time remote expert guidance. Basic, rapidly assimilated, instructional media (cue-cards and short instructional videos) provided adequate training to enable non-experts to obtain potentially important medical information using ultrasound. NASA researchers have demonstrated the utility of ultrasound in space medicine to provide timely answers for medical conditions which may occur in space. This preliminary report suggests that this technology can provide an in-expensive, deployable, and scalable diagnostic solution for a variety of health care challenges worldwide. The early diagnosis and medical management of medical problems in geographically distant locations could lessen the morbidity and mortality that disproportionately affect those living in these areas.