Vol 45, No 7 (2019)

The system of medical care used in the Russian segment of the International Space Station in space missions is directed to support space crews in orbital flights. The system gives the priority to the telemedicine rather than medical procedures performed by the crew autonomously. The long-term experience showed effectiveness of the existing system for medical support of orbital flights; however, travels beyond the low-Earth’s orbit add substantial limitations calling for reconsideration of approaches to the crew medical care. Among the special features of these missions will be increasing time of autonomy. There is a high probability that crews will have to make medical decisions by themselves and computer-assisted systems are likely to be a proper tool of health care. The software of medical inventory control and practice guidance developed in the Institute for Biomedical Problems (IBMP) enhances quality of the day-to-day use of medical resources at the Russian Orbital Segment and can serve as a prototype of a medical decision support system within the intelligent circuit aboard future piloted spacecraft.

EEG-reactions of subjects to breathing different artificial gas mixtures were studied at the IBMP Deepwater Diving Facility (GVK-250). The subjects descended to a depth of 2 m relative to the sea level, breathed oxygen–nitrogen and oxygen–nitrogen–argon mixtures for ten days, and an oxygen–nitrogen–argon mixture when descended to a depth of 20 m for seven days. EEG was recorded from six subjects to estimate relative values of the main band powers, global correlation dimension D2 and to perform qualitative analysis of individual EEG patterns. Significant one-way shifts in the EEG quantitative and qualitative parameters were shown by the subjects at a depth of 20 m breathing the O₂-N-Ar air mixture. When they breathed this mixture for ten days at a depth of 2 m, functioning of the brain cortex was almost optimal. Ten days in the hypoxic NO₂ atmosphere did not cause any distinct changes in the EEG spectral parameters.

This paper provides a review of experiments with extended confinement and isolation of small groups of volunteers in controlled environments. These studies provide opportunities to test approaches and tools enhancing the systems of biomedical support to space crews and to lay the groundwork of remote autonomous space missions in future. This review describes scenarios, goals, objectives, and main results of the long-duration isolation projects carried out at the Ground-Based Test Facility of the Institute for Biomedical Problems (IBMP) since 1960s and a forthcoming series of the Sirius analog studies. The authors elaborate on the fundamental principles of successful and productive accomplishment of this type of projects.

Insufficient levels of physical activity is among the leading risk factors of some chronic diseases and premature death. Effects of a reduced level of locomotor activity on human physiology were studied under the conditions of a 520-day isolation experiment simulating a space mission to Mars. A cohort of participants included 6 healthy men from different countries. As a prophylactic against negative effects of reduced locomotor activity, the volunteers performed cyclical exercises on an active treadmill (the moving belt was motorized), a passive treadmill (the belt was moved by the force of human legs), and on a bicycle ergometer. Resistive exercises were performed on the strength training device Multifunctional Dynamometer for Application in Space (MDS), a vibration platform, and with expanders. Three breaks in workouts as the control “pure” isolation periods, when training exercises were suspended, were included into the study program design. The experiment design allowed performing a comparative efficiency analysis of workouts on each of the applied devices in the conditions of reduced locomotor activity. According to the multiparametric assessment, the prophylactic devices were evaluated in terms of efficiency in the following descending order: the passive treadmill, the vibration platform, and the MDS strength training device.

The purpose of this investigation was to estimate the efficiency of training with expanders and power trainers against changes in bone mineral density (BMD) during long-duration space missions. The same group of cosmonauts was tested in two different missions aboard the International Space Station. Resistive exercises using expanders and training equipment were done every other day as was recommended by Russian coaches. Settings of the treadmill and bicycle ergometer programs did not differ much in the missions. Preventive efficiency of resistive exercises was evaluated by the results of pre- and post-mission densitometry (Hologic Delphy) of the lumbar vertebrae (L₁–L₄), femoral neck, and greater trochanter. It was shown that the use of power trainers is explicitly more effective in BMD loss prevention than expanders. In light of prospective exploration missions, it is an important result that suggests that mineral density in the lower part of the skeleton could be kept under control despite prolonged exposure to microgravity through daily resistive exercises using power trainers.

The article presents retrospective analysis of the data obtained by in-flight monitoring of the work and rest cycle (WRC) of the Russian ISS crewmembers. The authors list the specific elements of the analysis, score crew overworks, provide evidence for the negative effect of strenuous WRC on the mental state and performance of cosmonauts, and reaffirm the validity of the crew time management rules and constraints.

Venous circulation in the brain was investigated in a three-day “dry” immersion experiment. The aim of the study was to estimate the influence of microgravity factors on venous drainage from the cranial cavity. Duplex scanning and Doppler ultrasound were used to record hemodynamic parameters of the cervical main veins and orbital and cerebral venous sinuses. A significant decrease in blood flow along the jugular pathway with the activation of additional pathways of both the extra- and intracranial divisions of the venous system of the brain was detected. These results suggest that microgravity triggers the mechanisms capable of compensating the increasing intracranial venous pressure. The fact that in some volunteers the intracranial venous blood flow did not accelerate may reflect anatomical features and require a more scrupulous investigation of their venous systems.

After medical examination, members of flying personnel were divided into a group of essentially healthy people (control) and a group with the risk of preneurotic disorders due to lowered mental adaptability to the flying environment. A rehabilitation program consisting of a system of person-centered rational psychotherapy supported by a course of holotropic breathwork (breathing and ideomotor exercises) proved to be effective in abating preneurotic disorders. Altered states of consciousness achieved by holotropic breathwork have helped to correct rigid dominant mental conditions that distort the sense of professional motivation and deform behavioral typology. Therefore, holotropic breathwork recovers adaptability of pilot’s personality as a whole.

This study focuses on the investigation of the effects of flight factors, including the hypobaric hypoxia, on physical performance based on the individual psychological profile. The goal of the study was to evaluate the association between the endurability of the flight factors and individual psychological features. Physical performance was assessed using the Ruffier test in three stages: during the recording of the baseline data, when ascending to an altitude of 5000 m in a hypobaric chamber, and after the ascent. The data obtained were analyzed considering the individual psychological features, including the neuroticism, extroversion, and trait anxiety. The levels of neuroticism and extroversion were evaluated using the Eysenck Personality Questionnaire, and trait anxiety was assessed using Spielberger’s tests in the modification of Khanin. It has been found that individuals with a high neuroticism level are characterized by a more significant decrease in myocardial work capacity by 17.3% (p < 0.05) on the 30th minute and by 23.4% (р < 0.01) on the 60th minute of ascent in the hypobaric chamber compared to the subjects with a low neuroticism level. The results of the analysis of the Ruffier test have demonstrated 2.16-fold (р < 0.01) and 2.25-fold (р < 0.01) increase in the Ruffier index by the 30th and 60th minutes of the ascent in the altitude chamber, respectively, in the individuals characterized by an initially 28% lower (р < 0.05) baseline Ruffier index compared to those with high level of trait anxiety. Comparison of the indices of the myocardial work capacity during ascent has shown that heart work capacity in the group of introverts decreased by 20.0% (p < 0.05) by the 30th minute of being in a hypobaric chamber compared to the group of extroverts; by the 60th minute, the difference was 17.8% (р < 0.01). Therefore, it has been demonstrated that the association between the myocardial work capacity and individual psychological characteristics should be considered in the evaluation of the tolerance to moderate hypoxia.

The flight factors in highly maneuverable aircrafts lead to a significant and early progress of maladaptive shifts in pilot’s body as compared with non-flying professions. The aim of this study was to find out whether glycogen and lipid contents in segmented neutrophils of pilot peripheral blood depend on age and total flight hours, and to use findings for prenosological diagnostics of maladaptive shifts in body. The results of cytochemical studies of the content of glycogen and lipids in neutrophils from peripheral blood of pilots during their training flights are given. It has been established that a persistent increase in lipid content in neutrophils with an mean cytochemical coefficient higher than 2.60, along with a decrease in glycogen content in these cells at less than 2.00, indicates a decrease in the energy reserves of phagocytes, and peripheral blood leukocyte cell maladaptation. This condition develops as a response of the pilot’s body to the complex effect of flight factors on highly maneuverable aircraft with a total flight time of more than 1500 h and a pilot age of 36 years or more. The revealed patterns can be used in prenosological diagnostics of flight personnel.