Thoracic sonography for pneumothorax: the clinical evaluation of an operational space medicine spin-off

The recent interest in the use of ultrasound (US) to detect pneumothoraces after acute trauma in North America was initially driven by an operational space medicine concern. Astronauts aboard the International Space Station (ISS) are at risk for pneumothoraces, and US is the only potential medical imaging available. Pneumothoraces are common following trauma, and are a preventable cause of death, as most are treatable with relatively simple interventions. While pneumothoraces are optimally diagnosed clinically, they are more often inapparent even on supine chest radiographs (CXR) with recent series reporting a greater than 50% rate of occult pneumothoraces. In the course of basic scientific investigations in a conventional and parabolic flight laboratory, investigators familiarized themselves with the sonographic features of both pneumothoraces and normal pulmonary ventilation. By examining the visceral–parietal pleural interface (VPPI) with US, investigators became confident in diagnosing pneumothoraces. This knowledge was subsequently translated into practice at an American and a Canadian trauma center. The sonographic examination was found to be more accurate and sensitive than CXR (US 96% and 100% versus US 74% and 36%) in specific circumstances. Initial studies have also suggested that detecting the US features of pleural pulmonary ventilation in the left lung field may offer the ability to exclude serious endotracheal tube malpositions such as right mainstem and esophageal intubations. Applied thoracic US is an example of a clinically useful space medicine spin-off that is improving health care on earth.     

The SEVAN Worldwide network of particle detectors: 10 years of operation

The Space Environment Viewing and Analysis Network (SEVAN) aims to improve the fundamental research on particle acceleration in the vicinity of the sun, on space weather effects and on high-energy physics in the atmosphere and lightning initiation. This new type of a particle detector setup simultaneously measures fluxes of most species of secondary cosmic rays, thus being a powerful integrated device for exploration of solar modulation effects and electron acceleration in the thunderstorm atmosphere. The SEVAN modules are operating at the Aragats Space Environmental Center (ASEC) in Armenia, in Croatia, Bulgaria, Slovakia, the Czech Republic (from 2017) and in India. In this paper, we present the most interesting results of the SEVAN network operation during the last decade. We present this review on the occasion of the 10th anniversary of the International Heliophysical Year in 2007.     

Intuitive ultrasonography for autonomous medical care in limited-resource environments

Management of health problems in limited resource environments, including spaceflight, faces challenges in both available equipment and personnel. The medical support for spaceflight outside Low Earth Orbit is still being defined; ultrasound (US) imaging is a candidate since trials on the International Space Station (ISS) prove that this highly informative modality performs very well in spaceflight. Considering existing estimates, authors find that US could be useful in most potential medical problems, as a powerful factor to mitigate risks and protect mission. Using outcome-oriented approach, an intuitive and adaptive US image catalog is being developed that can couple with just-in-time training methods already in use, to allow non-expert crew to autonomously acquire and interpret US data for research or diagnosis.The first objective of this work is to summarize the experience in providing imaging expertise from a central location in real time, enabling data collection by a minimally trained operator onsite. In previous investigations, just-in-time training was combined with real-time expert guidance to allow non-physician astronauts to perform over 80 h of complex US examinations on ISS, including abdominal, cardiovascular, ocular, musculoskeletal, dental/sinus, and thoracic exams. The analysis of these events shows that non-physician crew-members, after minimal training, can perform complex, quality US examinations. These training and guidance methods were also adapted for terrestrial use in professional sporting venues, the Olympic Games, and for austere locations including Mt. Everest.The second objective is to introduce a new imaging support system under development that is based on a digital catalog of existing sample images, complete with image recognition and acquisition logic and technique, and interactive multimedia reference tools, to guide and support autonomous acquisition, and possibly interpretation, of images without real-time link with a human expert. In other words, we are attempting to replace, to the extent possible, expert guidance by guidance from a digital information resource. This is a next logical phase of the authors’ sustained effort to make US imaging available to sites lacking proper expertise. This effort will benefit NASA as the agency plans to develop future human exploration programs requiring increased medical autonomy. The new system will be readily adaptable to terrestrial medicine including emergency, rural, and military applications.     

Right ventricular tissue Doppler assessment in space during circulating volume modification using the Braslet device

Introduction: This joint US–Russian work aims to establish a methodology for assessing cardiac function in microgravity in association with manipulation of central circulating volume. Russian Braslet-M (Braslet) occlusion cuffs were used to temporarily increase the volume of blood in the lower extremities, effectively reducing the volume in central circulation. The methodology was tested at the International Space Station (ISS) to assess the volume status of crewmembers by evaluating the responses to application and release of the cuffs, as well as to modified Valsalva and Mueller maneuvers. This case study examines the use of tissue Doppler (TD) of the right ventricular (RV) free wall. Results: Baseline TD of the RV free wall without Braslet showed early diastolic E′ (16 cm/s), late diastolic A′ (14 cm/s), and systolic S′ (12 cm/s) velocities comparable with those in normal subjects on Earth. Braslet application caused 50% decrease of E′ (8 cm/s), 45% increase of A′, and no change to S′. Approximately 8 beats after the Braslet release, TD showed E′ of 8 cm/s, A′ of 12 cm/s, and S′ of 13 cm/s. At this point after release, E′ did not recover to baseline values while l A′ and S′ did recover. The pre-systolic cross-sectional area of the internal jugular vein without Braslet was 1.07 cm², and 1.13 cm² 10 min after the Braslet was applied. The respective cross-sectional areas of the femoral vein were 0.50 and 0.54 cm². The RV myocardial performance Tei index was calculated by dividing the sum of the isovolumic contraction time and isovolumic relaxation time by the ejection time ((IVCT+IVRT)/ET); baseline and Braslet-on values for Tei index were 0.25 and 0.22, respectively. Braslet Tei indices are within normal ranges found in healthy terrestrial subjects and temporarily become greater than 0.4 during the dynamic Braslet release portion of the study. Conclusions: TD modality was successfully implemented in space flight for the first time. TD of RV revealed that the Braslet influenced cardiac preload and that fluid was sequestered in the lower extremity interstitial and vascular space after only 10 min of application. This report demonstrates that Braslet application has an effect on RV physiology in long-duration space flight based on TD, and that this effect is in part due to venous hemodynamics.