Hemodynamic Responses and G Protection Afforded by Three Different Anti-G Systems

BACKGROUND: UK Royal Air Force fast jet aircrew use three different anti-G systems, however, little objective comparison of the G protection they provide exists. The G-protection afforded by each system and associated hemodynamic responses were investigated.METHODS: Ten subjects performed centrifuge acceleration exposures using Mk-10 (S1) and Mk-4 (S2) five-bladder anti-G trousers (AGT) and full coverage AGT plus pressure breathing for G-protection (PBG; S3). Measurements of relaxed G tolerance (RGT), eye-level blood pressure (BP_eye), lower body blood volume (LBV), stroke volume (SV) and total peripheral resistance (TPR) were made during gradual onset runs (GOR) and rapid onset runs (ROR). The subjective effort required to maintain clear vision at +7 and +8 G_z provided an indication of the protection provided by the system.RESULTS: All systems moderated decreases in SV and BP_eye and increases in LBV under increased +G_z. S3 provided the greatest mean RGT during GOR (+6.2 G_z) and ROR (+6 G_z), reduced the effort required to maintain clear vision at up to +8 G_z, prevented venous pooling and afforded the greatest rise in TPR. The majority of indices revealed no difference between S1 and S2 although RGT during the ROR was greater with S2 (+0.25 G_z).DISCUSSION: S3 effectively prevented pooling of blood in the lower limbs under +G_z, despite the use of PBG, and offers an advantage over five-bladder AGT. Given the similarities of S1 and S2, it was unsurprising that the majority of indices measured were similar. The objective measurement of hemodynamic parameters provides useful information for comparing the G-protection provided by anti-G systems.Pollock RD, Firth RV, Storey JA, Phillips KE, Connolly DM, Green NDC, Stevenson AT. Hemodynamic responses and G protection afforded by three different anti-G systems. Aerosp Med Hum Perform. 2019; 90(11):925-933.

Continuous Glucose Monitoring for In-Flight Measurement of Glucose Levels of Insulin-Treated Pilots

INTRODUCTION: Due to the risk of hypoglycemia-related incapacitation, diabetic pilots requiring insulin are assessed as unfit according to the International Civil Aviation Organization and most national authorities. Some authorities, such as those from Canada, the United Kingdom, and the United States, permit selected insulin-treated pilots (ITDM-pilots) to fly subject to a protocol requiring pre- and in-flight capillary glucose measurements to show safe levels (>100-<300 mg · dl^-1). Critics of such permission question the practicability of these in-flight measurements and whether clinically desired glycemic targets can be achieved while keeping glucose levels in the safe range. Subcutaneous continuous glucose monitoring (CGM) has recently been approved by the FDA as a stand-alone method to provide accurate glucose levels and treatment decision guidance in patients. This commentary considers that use of CGM by ITDM pilots facilitates practicability and recording of in-flight glucose measurements and facilitates achievement of clinically desired glycemic targets without increasing hypoglycemia risks.Strollo F, Simons R, Mambro A, Strollo G, Gentile S. Continuous glucose monitoring for in-flight measurement of glucose levels of insulin-treated pilots. Aerosp Med Hum Perform. 2019; 90(8):735-737.

High Altitude Performance of Loudspeakers and Potential Impact on Audiometric Findings

BACKGROUND: The evaluation of how air rarefaction can affect a loudspeaker performance at altitude implies the need for characterization of earphones during hypobaric conditions. The aim of this study was phonometric analysis at different altitudes of the acoustic output of a widely used earphone model, along with its consequences on audiological investigations conducted under such environmental conditions.METHODS: The transfer function of a TDH-39P earphone was analyzed with an artificial ear under nine different altitude levels, from sea level up to 35,000 ft, inside a hypobaric chamber. A specific phonometric system not sensitive to environmental pressure changes was used. Other potentially confounding factors, such as environmental temperature and humidity, were continuously monitored.RESULTS: No relevant temperature or humidity changes were detected. The sound pressure level generated by the earphone under hypobaric conditions was found considerably affected by air density changes. These data produced a correction table aiming at recalibrating the earphone's output at each audiometric octave test frequency within the 250-8000 Hz range. Quite different characteristics of response were observed at different audiometric frequencies. Such findings were particularly evident for altitudes exceeding 12,000 ft.DISCUSSION: The development of a frequency-selective and altitude-related correction factor for acoustic stimuli is an essential aspect when hearing threshold measurements in hypobaric environments are performed.Lucertini M, Botti T, Sanjust F, Cerini L, Autore A, Lucertini L, Sisto R. High altitude performance of loudspeakers and potential impact on audiometric findings. Aerosp Med Hum Perform. 2019; 90(7):655-659.

Gender Differences in Dry-EEG Manifestations During Acute and Insidious Normobaric Hypoxia

INTRODUCTION: Prior research suggests there may be gender differences with regards to hypoxia resilience. Our study was designed to determine whether there were differences between genders in neuronal electrical activity at simulated altitude and whether those changes correlated with cognitive and aviation performance decrements.METHODS: There were 60 student Naval Aviators or Flight Officers who completed this study (30 women, 30 men). Participants were exposed to increasing levels of normobaric hypoxia and monitored with dry EEG while flying a fixed-base flight simulation. Gender differences in brainwave frequency power were quantified using MATLAB. Changes in flight and cognitive performance were analyzed via simulation tasks and with a cognitive test validated under hypoxia.RESULTS: Significant decreases in theta and gamma frequency power occurred for women compared to men with insidious hypoxic exposures to 20K, with an average frequency power decrease for women of 19.4% compared to 9.3% for men in theta, and a 42.2% decrease in gamma for women compared to 21.7% for men. Beta frequency power correlated highest between genders, with an average correlation coefficient of r = 0.95 across seven channels.DISCUSSION: Results of this study suggest there is identifiable brain wave suppression for both men and women with hypoxic exposure and, moreover, there are significant differences in this suppression between genders. Beta frequency power was most sensitive for both genders and highly correlative compared to other brainwave frequencies. The implications of these findings are important considerations for next-generation aviation helmets, which may employ this technology as an early warning mechanism.Rice GM, Snider D, Drollinger S, Greil C, Bogni F, Phillips J, Raj A, Marco K, Linnville S. Gender differences in dry-EEG manifestations during acute and insidious normobaric hypoxia. Aerosp Med Hum Perform. 2019; 90(4):369-377.

Ergonomic evaluation of pilot oxygen mask designs

A revised pilot oxygen mask design was developed for better fit to the Korean Air Force pilots' faces. The present study compared an existing pilot oxygen mask and a prototype of the revised mask design with 88 Korean Air Force pilots in terms of subjective discomfort, facial contact pressure, and slip distance on the face in high gravity. The average discomfort levels, facial contact pressures, and slip distance of the revised mask were reduced by 33%-56%, 11%-33%, and 24%, respectively, compared to those of the existing oxygen mask. The mask evaluation method employed in the study can be applied to ergonomic evaluation of full- or half-face mask designs.

[MODERN INSTRUMENTS FOR EAR, NOSE AND THROAT RENDERING AND EVALUATION IN RESEARCHES ON RUSSIAN SEGMENT OF THE INTERNATIONAL SPACE STATION]

The paper reports the results of testing some diagnostic video systems enabling digital rendering of TNT teeth and jaws. The authors substantiate the criteria of choosing and integration of imaging systems in future on Russian segment of the International space station kit LOR developed for examination and download of high-quality images of cosmonauts' TNT, parodentium and teeth.

Simulator Study of Helmet-Mounted Symbology System Concepts in Degraded Visual Environments

BACKGROUND

A sudden loss of external visual cues during critical phases of flight results in spatial disorientation. This is due to undetected horizontal and vertical drift when there is little tolerance for error and correction delay as the helicopter is close to the ground. Three helmet-mounted symbology system concepts were investigated in the simulator as potential solutions for the legacy Griffon helicopters.

METHOD

Thirteen Royal Canadian Air Force (RCAF) Griffon pilots were exposed to the Helmet Display Tracking System for Degraded Visual Environments (HDTS), the BrownOut Symbology System (BOSS), and the current RCAF AVS7 symbology system. For each symbology system, the pilot performed a two-stage departure and a single-stage approach. The presentation order of the symbology systems was randomized. Objective performance metrics included aircraft speed, altitude, attitude, and distance from the landing point. Subjective measurements included situation awareness, mental effort, perceived performance, perceptual cue rating, and NASA Task Load Index. Repeated measures analysis of variance and subsequent planned comparison for all the objective and subjective measurements were performed between the AVS7, HDTS, and BOSS.

RESULTS

Our results demonstrated that HDTS and BOSS showed general improvement over AVS7 in two-stage departure. However, only HDTS performed significantly better in heading error than AVS7. During the single-stage approach, BOSS performed worse than AVS7 in heading root mean square error, and only HDTS performed significantly better in distance to landing point and approach heading than the others.

DISCUSSION

Both the HDTS and BOSS possess their own limitations; however, HDTS is the pilots' preferred flight display.

Development of Air Force Aerial Spray Night Operations: High Altitude Swath Characterizations

Multiple trials were conducted from 2006 to 2014 in an attempt to validate aerial spray efficacy at altitudes conducive to night spray operations using night vision goggles (NVGs). Higher altitude application of pesticide (more than 400 ft (121.9 m) above ground level (AGL)) suggested that effective vector control might be possible under ideal meteorological conditions. A series of lower altitude daytime applications (300 ft (91.4 m) AGL) demonstrated effective and repeatable mortality of target sentinel insects more than 5,000 ft (1,524 m) downwind, and control of natural vector populations. From these results we believe further pursuit of aerial night applications of pesticide using NVGs at 300 ft (91.4 m) AGL by this group is warranted.

Visual blur and motion sickness in an optokinetic drum

BACKGROUND

The most commonly cited hypotheses for motion sickness (MS) focus on inconsistent sensory inputs. Visual/vestibular conflicts may lead to MS, but visual input from retinal regions/neural pathways that are sensitive to motion might bear more weight in MS etiology. We hypothesized that inducing blurred vision in an optokinetic drum would attenuate the influence of foveal (parvocellular) input, but not peripheral (magnocellular) input that is sensitive to motion. Increased relative influence of peripheral visual input was predicted to subsequently lead to more visual/vestibular conflict and subsequently more severe MS symptoms.

METHODS

Through goggles that were either clear or frosted, 15 subjects (5 men, 10 women, mean age = 24.9 yr, range = 18-49) viewed the interior of a rotating (60° · s(-1)) optokinetic drum for 10 min. Subjects completed the Simulator Sickness Questionnaire (SSQ) before and after viewing. Overall subjective sickness ratings (0-10) and visually induced self-motion perception (vection) ratings (0-10) were also recorded.

RESULTS

Postexposure SSQ scores obtained in the blur condition (total - 52.9, oculomotor - 38.9, disorientation - 69.6) were significantly higher than those obtained in the control condition (total - 30.4, oculomotor - 21.7, disorientation - 37.8). Overall sickness ratings and vection ratings were also significantly higher in the blur condition.

CONCLUSIONS

These results suggest that visual blur can exacerbate MS, perhaps because of differential influences of visual pathways. Although these results were obtained with an optokinetic drum, possible effects of visual blurring in motion provocative environments such aircraft, watercraft, spacecraft, and land vehicles should be considered.

Adaptive data filtering of inertial sensors with variable bandwidth

MEMS (micro-electro-mechanical system)-based inertial sensors, i.e., accelerometers and angular rate sensors, are commonly used as a cost-effective solution for the purposes of navigation in a broad spectrum of terrestrial and aerospace applications. These tri-axial inertial sensors form an inertial measurement unit (IMU), which is a core unit of navigation systems. Even if MEMS sensors have an advantage in their size, cost, weight and power consumption, they suffer from bias instability, noisy output and insufficient resolution. Furthermore, the sensor's behavior can be significantly affected by strong vibration when it operates in harsh environments. All of these constitute conditions require treatment through data processing. As long as the navigation solution is primarily based on using only inertial data, this paper proposes a novel concept in adaptive data pre-processing by using a variable bandwidth filtering. This approach utilizes sinusoidal estimation to continuously adapt the filtering bandwidth of the accelerometer's data in order to reduce the effects of vibration and sensor noise before attitude estimation is processed. Low frequency vibration generally limits the conditions under which the accelerometers can be used to aid the attitude estimation process, which is primarily based on angular rate data and, thus, decreases its accuracy. In contrast, the proposed pre-processing technique enables using accelerometers as an aiding source by effective data smoothing, even when they are affected by low frequency vibration. Verification of the proposed concept is performed on simulation and real-flight data obtained on an ultra-light aircraft. The results of both types of experiments confirm the suitability of the concept for inertial data pre-processing.

Portable radiography: a reality and necessity for ISS and explorer-class missions

On ISS missions and explorer class missions, unexpected medical and surgical emergencies could be disastrous. Lack of ability to rapidly assess and make critical decisions affects mission capability. Current imaging modalities on ISS consist only of ultrasound. There are many acute diagnoses which ultrasound alone cannot diagnose. Portable X-Ray imaging (radiography) technology has advanced far enough to where it is now small enough, cheap enough, and accurate enough to give diagnostic quality images sent wirelessly to the onboard computer and on Earth for interpretation while fitting in something the size of a briefcase. Although further research is warranted, Portable Radiography is an important addition to have on ISS and future Explorer Class Missions while maintaining a very small footprint.

[Spatial orientation of pilot using a cockpit exterior surveillance system]

Spatial orientation of pilots using a cockpit exterior surveillance system was tested in real nighttime helicopter flights. Major factors complicating adequate spatial orientation and provoking visual illusions in pilots are lack of information for spatial depth (relation) perception in two-dimensional TV images altering their position along the horizontal and vertical lines of trajectory and simultaneous piloting and target search-identification operations. Reliability of pilot's spatial orientation could be improved by displaying on the exterior imaging screen also relevant flight navigation parameters.

Forgotten hardware: how to urinate in a spacesuit

On May 5, 1961, astronaut Alan Shepard became the first American to fly in space. Although National Aeronautics and Space Administration (NASA) had discounted the need for him to urinate, Shepard did, in his spacesuit, short circuiting his electronic biosensors. With the development of the pressure suit needed for high-altitude and space flight during the 1950s, technicians had developed the means for urine collection. However, cultural mores, combined with a lack of interagency communication, and the technical difficulties of spaceflight made human waste collection a difficult task. Despite the difficulties, technicians at NASA created a successful urine collection device that John Glenn wore on the first Mercury orbital flight on February 20, 1962. With minor modifications, male astronauts used this system to collect urine until the Space Shuttle program. John Glenn's urine collection device is at the National Air and Space Museum and has been on view to the public since 1976.

[New technologies for evaluation of health status of apparently healthy people]

The article considers the questions of development of new technologies for evaluation of health of apparently healthy people based on experience of long-term researches of cosmonauts' performed at Russian Academy of Sciences Institute of Biomedical Problems under the direction of academician A. I. Grigoriev. In 2007 in monograph "Concept of Health and Space Medicine" the principle of health estimation in apparently healthy people working in conditions of chronic stress was described. These approaches were realized the same year to produce a new hard and software "Ecosan-2007". In the following 2008 the device has been tested for inspection of bus drivers and pilots of civil aircraft and since 2009 it has been used in the international project "Mars-500". All these developments and researches were supported by the Fundamental Sciences-to-Medicine Program maintained by the Presidium of the Russian Academy of Sciences under guidance of academician A. I. Grigoriev. In the project 'Mars-500" in the "artificial confinement", simulating the interplanetary ship, 6 members of the international "Martian crew" were medically and psycho physiologically surveyed. Among set of various devices the "Ecosan-2007" was also used. With application of the same device, not less that 125 volunteers were examined, who lived usual life in natural and socially-industrial conditions. The investigation was simultaneously conducted in 12 various regions of the world. These long-term medico-ecological researches allowed to receive important experimental substantiations for preclinical approach to state of health estimation. In the frame of these researches the methodology of remote monitoring of adverse ecological factor effects on health initiated telemedical ecology, a new applied discipline. The article concludes with discussion of the issues of health conception and new preclinical diagnostic technologies adapting by the public health services.

[I.M. Sechenov's creative development of ideas in aviation and space medicine]

Research carried outby the great Russian scholar I. M. Sechenov has significantly contributed to development of aviation physiology, medicine and psychology. His fundamental works consisted of discovery of the constancy of alveolar air composition theory, study of interactions of analyzers systems in solving the problem of human spatial orientation under flight conditions, development of a nervous theory of fatigue. Creative development of ideas by I. M. Sechenov allowed enhancing the efficiency of performing and safety of aviation and space flights.

In-flight urine collection device: efficacy, maintenance, and complications in U-2 pilots

INTRODUCTION

Urine collection systems for in-flight use have gradually improved over the past 50 yr; however, current management of urine evacuation remains suboptimal. This is a cross-sectional survey-based study on the current urine collection device employed in the U.S. Air Force's U-2S airframe, examining efficacy, problems with wear, device maintenance, and complaint reporting.

METHODS

An anonymous survey consisting of 18 questions was generated inquiring about problems with wear of the urine collection system, care of the device, and education. The survey was offered at Beale AFB and overseas U-2 locations to pilots with at least 180 h of flying experience with the airframe.

RESULTS

There were 57 subjects who completed the survey with 62.5% reporting complications, including mechanical dysfunction, pain and poor fit, skin irritation, allergic reaction, embarrassment, and urethral issues. Variation was seen in the degree of problem reporting and care of the device. Discussion and literature review is provided on in-flight and space urine collection and evacuation systems, sheath catheters, urine and contact dermatitis, urethritis, external catheter sizing methods, and psychological aspects of catheter use.

CONCLUSIONS

The majority of surveyed pilots experienced various problems associated with wear of their urine collection device. Also, variation in reporting and care of the device exists. Potential improvements include standardization of fitting procedures and device maintenance, increased catheter draining capacity, use of skin barriers to urine, enhanced privacy measures, and incorporation of less injurious structural materials such as silicone.

[Some approaches to the countermeasure system for a mars exploration mission]

In article discussed physiological and methodical principles of the organization of training process and his (its) computerization during Martian flight in conditions of autonomous activity of the crew, providing interaction with onboard medical means, self-maintained by crew of the their health, performance of preventive measures, diagnostic studies and, in case of necessity, carrying out of treatment. In super long autonomous flights essentially become complicated the control of ground experts over of crew members conditions, that testifies to necessity of a computerization of control process by a state of health of crew, including carrying out of preventive actions. The situation becomes complicated impossibility of reception and transfer aboard the necessary information in real time and emergency returning of crew to the Earth. In these conditions realization of problems of physical preventive maintenance should be solved by means of the onboard automated expert system, providing management by trainings of each crew members, directed on optimization of their psychophysical condition.

[On-board medical support system (MSS) of flights of promising aerospace sets (design)]

It was suggested as the main compositive fractions MSS to consider the base system of automated evaluation of blood redistribution (BR) in body means of crew members protection and prophylaxis (CMPP) of unfavourable effects of flight factors to organism and also the automated circuit of CMPP' control. The advanced MSS includes 4 original measuring channels for registration of the base physiologic indices (electrocardiogram, venous-arterial pulsegram of neck vessels, reogram of head, earlap vessels pulsegram) the dynamic of which allows to determine with the help of computer the BR-integral parameter. The CMPP automated control circuit unites the separate protecting means in common system and executes the individual selection of regimes and CM PP-composition in accord with, first of all, body reactions manifestation and, secondly, individual physiologic status of spaceman. As CMPP was selected the negative pressure production around lower body part. Approlation of constructed active laboratory engineering mock-up MSS has performed investigations with participation of 29 subjects (Volunteers) under the modeling of hemodynamic shifts, developing in human body in short-term antiorthostatic hypokinesia (-10 degrees), as well as, in combined effect of antiorthostatic hypokinesia (-10 degrees), Coriolis acceleration and optokinetic stimulation. Results of investigations have showed, that the use of advanced MSS gives the indices of operator professional activity on the average of 17-32% under the decrease of hemodynamic stressful.

Medical issues associated with commercial flights

Almost 2 billion people travel aboard commercial airlines every year. Health-care providers and travellers need to be aware of the potential health risks associated with air travel. Environmental and physiological changes that occur during routine commercial flights lead to mild hypoxia and gas expansion, which can exacerbate chronic medical conditions or incite acute in-flight medical events. The association between venous thromboembolism and long-haul flights, cosmic-radiation exposure, jet lag, and cabin-air quality are growing health-care issues associated with air travel. In-flight medical events are increasingly frequent because a growing number of individuals with pre-existing medical conditions travel by air. Resources including basic and advanced medical kits, automated external defibrillators, and telemedical ground support are available onboard to assist flight crew and volunteering physicians in the management of in-flight medical emergencies.

[Oxygen therapy during Argentine-based national and international flights]

There are no data about supplemental oxygen in flight in our country. The objective of our study was to evaluate arranging in-flight-oxygen required by a simulated traveler, system of administration and costs, and to compare the results between Argentine-based (A) and international (I) airlines. The questionnaire used was similar to that of Stoller et al12. Data collection consisted of telephone calls placed by one of the authors to all commercial air carriers listed in our two Buenos Aires City airports during July 2007. A structured interview with questions was addressed on issues that an oxygen-using air traveler would need to arrange in-flight oxygen. Of the 25 airlines, 6 were discarded because of lack of information (24%, three A -60%- and one I -16%-). All A allowed in-flight-oxygen vs. 80% of I (p<0.05), 100% of A and 94% of I required a medical certificate (p=NS); 71% of A and 100% of I required previous notification (p<0.05); 50% of A and 87% of I provided patient interphases of oxygen administration (p=NS). Free of charge oxygen could be provided by 100% of A and 50% of I, with airline charge between 70 to 300 dollars. In conclusion, we observed different policies, rules, availability, and a pronounced lack of standardization of airline information. The cost of oxygen was very different between airlines and it was superior on I. It will be necessary to carry out actions to facilitate patient access to oxygentherapy and to standardize medical information among airlines in our country.

[Effect of prophylactic device "Braslet" on hemodynamic changes during long-term missions to orbital station Mir]

The benefit from occlusive cuffs (prophylactic device Braslet) to human hemodynamics was evaluated in seven cosmonauts on long-term Mir missions using the ultrasonic technique (Echography and Doppler). Braslet had a positive effect on cosmonauts" state of health during the first month of flight. Improvement of cerebral hemodynamics was attested objectively by reduction of venous congestion. However, the device did not produce a noticeable effect on the leg vein expansibility and capacity at the beginning of long-term mission. Starting on flight month 3, cumulation of the Braslet effect on the leg large veins resulted in progressive vein expansion. Regular wearing of the Braslet device produced changes in expansibility, capacity and elasticity of the veins in lower extremities. Extent of these changes was dependent on period of Braslet application and tightness of occlusion. Though the state of leg veins of the cosmonauts who had been favourable to Braslet during mission did not appear changed after landing, still we cannot make the conclusion that the occlusive cuffs do not bring harm if worn continuously, as their delayed effects have not been evaluated and remain unknown.

[Water immersion as an anti-g protection for pilot. Pro et contra]

In the period of 1988 - 1990 the ZVEZDA Aerospace medicine Department fulfilled comprehensive physiological investigations in order to assess the prospects for water immersion as an anti-g gear for pilots of high-maneuver aircraft. Both dry and open water immersion methods were used. More than 150 centrifuge runs were conducted to define limits for the acceleration value and time of 9-g tolerance. Volunteered subjects in the pilot's posture were inclined at 35 degrees and 55 degrees to the total inertial force vector. The obvious subjective discomfort felt during acceleration and absence of clinical aftereffect were qualified as a positive outcome. The subjects were ready for repeated runs even after a very brief repose. The main impediment to the professional anti-g use of immersion is visual disorders which in this case are not predictors of coming loss of consciousness and attributed to alterations in regional hemodynamics. The authors assert that there is a good reason to continue search for implementation of the immersion principle in g-protection of pilots to reduce the rate of professional pathologies and to intensify flights.

Trauma sonography for use in microgravity

Sonography is the only medical imaging modality aboard the ISS, and is likely to remain the leading imaging modality in future human spaceflight programs. While trauma sonography (TS) has been well recognized for terrestrial trauma settings, the technique had to be evaluated for suitability in spaceflight prior to adopting it as an operational capability. The authors found the following four-phased evaluative approach applicable to this task: 1) identifying standard or novel terrestrial techniques for potential use in space medicine; 2) developing and testing these techniques with suggested modifications on the ground (1 G) either in clinical settings or in animal models, as appropriate; 3) evaluating and refining the techniques in parabolic flight (0 G); and 4) validating and implementing for clinical use in space. In Phase I of the TS project, expert opinion and literature review suggested TS to be a potential screening tool for trauma in space. In Phase II, animal models were developed and tested in ground studies, and clinical studies were carried out in collaborating trauma centers. In Phase III, animal models were flight-tested in the NASA KC-135 Reduced Gravity Laboratory. Preliminary results of the first three phases demonstrated the potential clinical utility of TS in microgravity. Phase IV studies have begun to address crew training issues, onboard imaging protocols, and data transfer procedures necessary to offer the modified TS technique for space use.

Battling fire and ice: remote guidance ultrasound to diagnose injury on the International Space Station and the ice rink

BACKGROUND

National Aeronautical and Space and Administration (NASA) researchers have optimized training methods that allow minimally trained, non-physician operators to obtain diagnostic ultrasound (US) images for medical diagnosis including musculoskeletal injury. We hypothesize that these techniques could be expanded to non-expert operators including National Hockey League (NHL) and Olympic athletic trainers to diagnose musculoskeletal injuries in athletes.

METHODS

NHL and Olympic athletic trainers received a brief course on musculoskeletal US. Remote guidance musculoskeletal examinations were conducted by athletic trainers, consisting of hockey groin hernia, knee, ankle, elbow, or shoulder evaluations. US images were transmitted to remote experts for interpretation.

RESULTS

Groin, knee, ankle, elbow, or shoulder images were obtained on 32 athletes; all real-time US video stream and still capture images were considered adequate for diagnostic interpretation.

CONCLUSIONS

This experience suggests that US can be expanded for use in locations without a high level of on-site expertise. A non-physician with minimal training can perform complex, diagnostic-quality examinations when directed by a remote-based expert.

[A portable impedance meter for monitoring liquid compartments of human body under space flight conditions]

A portable two-frequency tetrapolar impedance meter was developed to study the state of liquid compartments of human body under zero-gravity conditions. The portable impedance meter makes it possible to monitor the hydration state of human body under conditions of long-term space flight on board international space station.

The bioethics of enhancing human performance for spaceflight

There are many ways of enhancing human performance. For military aviation in general, and for spaceflight in particular, the most important tools are selection, training, equipment, pharmacology, and surgery. In the future, genetic manipulation may be feasible. For each of these tools, the specific modalities available range from the ethically acceptable to the ethically unacceptable. Even when someone consents to a particular procedure to enhance performance, the action may be ethically unacceptable to society as a whole and the burden of risk for the individual may be too great. In addition, there are several characteristics that define the quality and the acceptability of the consent. Each method of enhancing performance will be examined in the context of the principles of medical ethics in a western society: autonomy, non-maleficence, beneficence, and justice. The aim is to draw the attention of aeromedical practitioners to the complexities of ethical dilemmas such as this particular one in order to help them to develop a morally justifiable code of practice that balances society's needs against individual ambitions and corporate goals.

A multiparameter wearable physiologic monitoring system for space and terrestrial applications

A novel, unobtrusive and wearable, multiparameter ambulatory physiologic monitoring system for space and terrestrial applications, termed LifeGuard, is presented. The core element is a wearable monitor, the crew physiologic observation device (CPOD), that provides the capability to continuously record two standard electrocardiogram leads, respiration rate via impedance plethysmography, heart rate, hemoglobin oxygen saturation, ambient or body temperature, three axes of acceleration, and blood pressure. These parameters can be digitally recorded with high fidelity over a 9-h period with precise time stamps and user-defined event markers. Data can be continuously streamed to a base station using a built-in Bluetooth RF link or stored in 32 MB of on-board flash memory and downloaded to a personal computer using a serial port. The device is powered by two AAA batteries. The design, laboratory, and field testing of the wearable monitors are described.

[A new type of active noise cancellation earmuffs]

OBJECTIVE

To develop a new type of feedback active noise cancellation earmuff (ANCE) for aviator's helmet.

METHOD

A mathematical model of such a structure was established based on frequency response function and automatic control theory. The method and role for designing ANCE controllers were summarized and the optimum design method was used for designing the controllers.

RESULT

The acoustic components and simulation circuit were well matched. One of the prototype can attenuate the noise more than 15 dB in the frequency range of 50-2000 Hz (19 dB at the highest).

CONCLUSION

The noise cancellation value of this earmuff has achieved international level and it can be mass-produced.

Do SpaceLabs ambulatory non-invasive blood pressure recorders measure blood pressure consistently over several years use?

OBJECTIVE

To assess the measurement consistency of SpaceLabs ambulatory recorders (Spacelabs, Washington, USA) that are in regular use.

METHODS

A total of 14 SpaceLabs 90207 and one 90217 ambulatory recorders were tested for measurement consistency using the Dynatech CuffLink (Dynatech, Nevada, USA), a commercially available non-invasive blood pressure (NIBP) simulator. The NIBP recorders were tested at a range of pressures with 20 repeated determinations at a simulated 120/80 mmHg and five repeated determinations at simulated pressures of 80/50, 100/80, 150/100, 200/165 and 250/195 mmHg. Tests were carried out in 1998, 2002 and late 2003 or early 2004.

CONCLUSIONS

All 15 SpaceLabs recorders measured consistently over the 6 years with 89.5% of the differences in average pressures, recorded by any particular device at each recorded pressure, less than 2 mmHg between successive test episodes. The maximum difference was 4.5 mmHg and 60.1% of the differences were less than 1 mmHg. The measurements for all devices were within the tolerances specified by the supplier for the device when tested with the simulator. Maintenance records also show that most devices required breakdown maintenance less than once every 3 years. The results show that the SpaceLabs devices maintain measurement consistency in the demanding conditions of ambulatory pressure recording over several years.

Cognitive avionics and watching spaceflight crews think: generation-after-next research tools in functional neuroimaging

Confinement and isolation have always confounded the extraordinary endeavor of human spaceflight. Psychosocial health is at the forefront in considering risk factors that imperil missions of 1- to 2-yr duration. Current crewmember selection metrics restricted to behavioral observation by definition observe rather than prevent performance degradation and are thus inadequate when preflight training cannot simulate an entire journey. Nascent techniques to monitor functional and task-related cortical neural activity show promise and can be extended to include whole-brain monitoring. Watching spaceflight crews think can reveal the efficiency of training procedures. Moreover, observing subcortical emotion centers may provide early detection of developing neuropsychiatric disorders. The non-invasive functional neuroimaging modalities electroencephalography (EEG), magnetoencephalography (MEG), magnetic resonance imaging (MRI), and near-infrared spectroscopy (NIRS), and highlights of how they may be engineered for spacecraft are detailed. Preflight and in-flight applications to crewmember behavioral health from current generation, next generation, and generation-after-next neuroscience research studies are also described. The emphasis is on preventing the onset of neuropsychiatric dysfunctions, thus reducing the risk of mission failure due to human error.

Development and validation of the spaceflight cognitive assessment tool for windows (WinSCAT)

The Spaceflight Cognitive Assessment Tool for Windows (WinSCAT) was developed by an integrated product team as a tool to support medical operations at NASA Johnson Space Center and as way to monitor the neurocognitive status of space crews. It is based on 20 yr of experience in performance and cognitive testing within the U.S. Department of Defense. As a result, WinSCAT development has benefited from diverse efforts supporting its technical reliability and validation. The rationale, background, and development of WinSCAT are described, research supporting its use is summarized, and recommendations are made for its continued development.

The minicog rapid assessment battery: developing a "blood pressure cuff for the mind"

Human exploration of space is a high-risk, high-stress endeavor. Thus, human error must be guarded against at every juncture. We have implemented a portable system, the MiniCog Rapid Assessment Battery, to assess quickly and accurately nine cognitive functions (including attention, working memory, and problem-solving). This system is intended to provide an "early warning," indicating when an astronaut or other type of worker is suffering from stress-related deficits that may affect performance. The results can be used to warn a worker to pay additional attention or take a countermeasure (even if only a brief rest). At present, the MiniCog platform is fully functional; it includes software for administering cognitive tests on a hand-held device and providing immediate user feedback, as well as desktop software for authoring new tests and scoring results in detail. Studies are underway to assess the utility of the MiniCog Rapid Assessment Battery for measuring impaired cognitive performance induced by a variety of stressors, for evaluating countermeasures, and for predicting performance on more complex tasks. We hope that this tool will allow quick and easy self-diagnosis of cognitive impairment, encouraging better mental health and facilitating safer on-the-job (and recreational) performance.

An interactive media program for managing psychosocial problems on long-duration spaceflights

Space crews must be self-reliant to complete long-duration missions successfully. This project involves the development and evaluation of a network of self-guided interactive multimedia programs to train and assist long-duration flyers in the prevention, assessment, and management of psychosocial problems that can arise on extended missions. The system is currently under development and is intended for use both during training and on orbit. A virtual space station 3-dimensional graphic was created to serve as a portal to multimedia-based training, assessment, and intervention resources. Additionally, original content on interpersonal conflict and depression is being developed for the system. Input on the best practices for managing conflict and depression on extended missions was obtained from 13 veteran long-duration flyers, as well as from clinical experts. Formative evaluation of a prototype of the system will be conducted with 10 members of the astronaut corps. Subsequently, the content on conflict and depression will be completed, and the depression self-treatment portion will be evaluated in a randomized controlled trial. Although this study involves developing countermeasures to assist long-duration flyers, it also provides a model that could be applied in many Earthbound settings, both in operational environments and in everyday life.

Color vision tests for aviation: comparison of the anomaloscope and three lantern types

INTRODUCTION

A comparison of the results obtained with the Nagel anomaloscope and the Holmes-Wright Type A, Spectrolux, and Beyne aviation color vision lanterns was undertaken. The Joint Aviation Requirements (JAR) specify pass/fail limits for these four secondary color vision tests and the Ishihara screening test. The results for individuals on all five tests were studied.

METHODS

The color vision of 55 color-vision deficient and 24 color-vision normal subjects, mostly applicant pilots, was assessed using a battery of tests, including the Ishihara plates, the Nagel anomaloscope, and three lanterns. The testing methods and characteristics of the lanterns and anomaloscope were compared.

RESULTS

Of the color-deficient applicants, only deuteranomalous trichromats passed more than one of the four secondary JAR tests, but a pass on one test did not reliably predict a pass on another test. Three out of nine protanomalous trichromats passed the Nagel anomaloscope but failed all three lantern tests. Of the normal trichromats, 12 failed the anomaloscope and 12 failed the Beyne lantern.

DISCUSSION

Variability in pass/fail results can be attributed to many factors apart from loss of chromatic sensitivity. Some normal trichromats can fail both the Ishihara screening and the secondary tests. The approved secondary test varies between countries and the outcome of regulatory assessment depends on the color vision test used. Since the flight safety consequences of the current situation cannot be ignored, the development of a less variable technique for color vision assessment that is accepted internationally, allied with a better understanding of color vision requirements, is needed.

Fatigue assessment in the field: validation of a hand-held electronic psychomotor vigilance task

INTRODUCTION

In recent years, there has been an increasing need for a reliable and practical tool for assessing fatigue-related impairment in the field. This study investigated the sensitivity of one potential tool, a 5-min version of the psychomotor vigilance task (PVT) specifically designed for use on personal digital assistants (PDA), to 28 h of sustained wakefulness.

METHODS

There were 15 participants who slept in the laboratory overnight then remained awake from 08:00 (Day 1) to 12:00 (Day 2). During every second hour, they completed a 10-min PVT, a sustained attention task that is sensitive to the effects of sleep loss and fatigue, and a 5-min PDA-PVT.

RESULTS

While performance on both tasks significantly varied as a function of hours of wakefulness, responses on the PDA-PVT were typically slower than on the PVT. When performance scores were standardized, the negative impact of increasing hours of wakefulness on performance on the 5-min PDA-PVT and 10-min PVT did not significantly differ.

DISCUSSION

The findings suggest that the 5-min PDA-PVT may provide a reasonable substitute for the 10-min PVT, particularly in circumstances where a shorter test is required and/or the standard PVT is not as practical.

Centrifuge training program with "push-pull" elements

INTRODUCTION

Pilots of fighter aircraft are often exposed to maneuvers that produce negative acceleration (-Gz) immediately followed by positive acceleration (+Gz). This sequence has been found to reduce tolerance to +Gz, a phenomenon known as the "push-pull" effect. We devised a centrifuge training program to demonstrate this phenomenon to pilots.

METHODS

The centrifuge of the Military Institute of Aviation Medicine in Warsaw, Poland, was modified in 1996 to allow active positioning of the gondola during rotation. Head-down position of -6 degrees to -40 degrees were used to produce relative -Gz (r-Gz) in a range down to 0.2. As a side effect, this produces Gy acceleration between -1.3 Gy and -1.6 Gy. Pilots completed normal centrifuge training, including a relaxed, gradual-onset run and three rapid-onset runs. They were then exposed to a profile that included a series of push-pull exposures where r-Gz was followed by +Gz with stepwise increases in the latter from +2.5 to +5 Gz. The final profile was a simulated aerial combat maneuver with push-pull elements.

RESULTS

The trainees expressed surprise at the push-pull effect, which forced them to begin an anti-G straining maneuver at lower levels than normal. They complained about the presence of the Gy, which rarely occurs in aircraft.

DISCUSSION

This type of profile appears useful for training pilots about the push-pull phenomenon. After collection of additional data, the profiles may be refined.

[Detection of small molecules based on surface plasmon (correction of plasman) resonance technology]

OBJECTIVE

To develop a detective method applied in online assaying of astronauts' humours using the portable online bio-molecules analyzer (POBA) based on surface plasmon resonance biosensor.

METHOD

An assay format was developed based on the detection of 2, 4-Dinitrophenyl-hydrazine. The bio-molecule slide was made by DNP-BSA. Range of detection and standard curve were obtained using inhibition assay. Reliability and specificity of the assay were also tested.

RESULT

1) The linear range of the assay was 7.8 ng/ml-2 micrograms/ml with lower detection limit of 2.5 ng/ml; 2) Preparation of the bio-molecule slide and regeneration of the biosensor ensured detections for many samples.

CONCLUSION

This assay method can be used to detect small molecules sensitively, rapidly and easily. It can be repeated with good reliability, and has a good application in space medicine.

A mathematical model of aircraft for evaluating the effects of shielding structure on aircrew exposure

To investigate the influence of the aircraft structures and contents on the exposure of aircrew to the galactic component of cosmic rays, a mathematical model of an aeroplane has been developed. The irradiation of the mathematical model in the cosmic ray environment has been simulated using the Monte Carlo transport code FLUKA. Effective dose andambient dose-equivalent rates have been determined inside the aircraft at several locations along the fuselage at a typicaI civil aviation altitude. A significant effect of the shielding of aircraft structures has been observed on the ambient dose-equivalent rates, while the impact on the effective dose rates seems to be minor. Care should be taken in positioning the detectors onboard when the measurements are aimed at validating the codes.

Space radiation measurements on-board ISS--the DOSMAP experiment

The experiment 'Dosimetric Mapping' conducted as part of the science program of NASA's Human Research Facility (HRF) between March and August 2001 was designed to measure integrated total absorbed doses (ionising radiation and neutrons), heavy ion fluxes and its energy, mass and linear energy transfer (LET) spectra, time-dependent count rates of charged particles and their corresponding dose rates at different locations inside the US Lab at the International Space Station. Owing to the variety of particles and energies, a dosimetry package consisting of thermoluminescence dosemeter (TLD) chips and nuclear track detectors with and without converters (NTDPs), a silicon dosimetry telescope (DOSTEL), four mobile silicon detector units (MDUs) and a TLD reader unit (PILLE) with 12 TLD bulbs as dosemeters was used. Dose rates of the ionising part of the radiation field measured with TLD bulbs applying the PILLE readout system at different locations varied between 153 and 231 microGy d(-1). The dose rate received by the active devices fits excellent to the TLD measurements and is significantly lower compared with measurements for the Shuttle (STS) to MIR missions. The comparison of the absorbed doses from passive and active devices showed an agreement within +/- 10%. The DOSTEL measurements in the HRF location yielded a mean dose equivalent rate of 535 microSv d(-1). DOSTEL measurements were also obtained during the Solar Particle Event on 15 April 2001.

[System automatically processing psychophysiologic parameters of pilots]

For ergonomic evaluation of aircraft, the authors developed and subjected to flight testing a system automatically processing psychophysiologic parameters of pilots, providing post-flight automated PC processing of values registered during flight--cardiac rhythm, skin and sub-clothing temperatures, pulmonary ventilation and working load.