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Biomedical subjects

A S Barer

Publications and source records attributed to A S Barer.

At least 19 recordsLinked to original sources
PubMed2004

The main results of EVA medical support on the Mir Space Station.

The aim of this paper is to review the main results of medical support of 78 two-person extravehicular activities (EVAs) which have been conducted in the Mir Space Program. Thirty-six male crewmembers participated in these EVAs. Maximum length of a space walk was equal to 7 h 14 min. The total duration of all space walks reached 717.1 man-hours. The maximum frequency of EVA's execution was 10 per year. Most of the EVAs (67) have been performed at mission elapsed time ranging from 31 to 180 days. The oxygen atmosphere of the Orlan space suit with a pressure of 40 kPa in combination with the normobaric cabin environment and a short (30 min) oxygen prebreathe protocol have minimized the risk of decompression sickness (DCS). There has been no incidence of DCS during performed EVAs. At the peak activity, metabolic rates and heart rates increased up to 9.9-13 kcal/min and 150-174 min-1, respectively. The medical problems have centred on feeling of moderate overcooling during a rest period in a shadow after the high physical loads, episodes with tachycardia accompanied by cardiac rhythm disorders at the moments of emotional stress, pains in the muscles and general fatigue after the end of a hard EVA. All of the EVAs have been completed safely.

Aerospace Medicine↗
PubMed1999

[The monitoring of gas bubbles with a pulsed Doppler ultrasonic locator in humans working in a space suit].

Presented are results of gas bubbles monitoring in decompressed humans with the use of an ultrasonic pulse-Doppler locator (PDL). Unlike the classic Doppler bubbles detectors with continuous US emission, PDL is adjusted for reception of echo from a chosen volume of the right ventricle cavity; thus, the clutter due to cardiac beats and human locomotion is successfully rejected. During simulation of Russian EVAs, venous gas bubbles were detected in 3 out of 5 experiments with test-subjects clothed in everyday wear and in 2 out of 3 experiments with suited test-subjects.

Adult↗
PubMed1998

[Effect of loading suit "Penguin" on human metabolism during movements].

Additional energy expenses due to stretching of the elastic elements of anti-loading suit (ALS) "Penguin" as a whole (shoulders-feet) or only its lower part (waist-feet) in the course of cyclic leg movements were measured in five female and five male volunteers. ALS design enabled tensometric monitoring of efforts applied to specific elastic elements, and total efforts applied to the shoulder or pelvic girdles separately. Energy spend were determined with the indirect calorimetric techniques from the data of the expired air analysis. Registered were electromyograms of m. longus spinae, femoral extensor (m. biceps femoris) and femoral flexor (m. rectus femoris), and m. gastrocnemius. On the first stage, bicycle ergometer was pedaled w/o loading with a frequency of 60 cycles/min. The next stage included testing by incremental loading in which pedaling ceased at the pulse rate of 150/min. Results of the experiments that did not require stretching elastic parts of the suit and in which the total strain effort made up 20 to 25 kg and 15 to 16 kg by males and females, respectively, were compared. It was ascertained that ALS enhanced metabolism during motion by 20 to 30%; however, there was no significant difference in energy expenses when loaded by the whole suit or only its lower part.

Adaptation, Physiological↗
PubMed1995

[Role of vestibular and visual analyzers in changes of postural activity of patients with childhood cerebral palsy in the process of treatment with space technology].

The paper presents the findings of stabiligraphic investigations of children afflicted with the hyperkinetic child's cerebral paralysis treated with the method of graduated wearing suit ADELI. This suit is a modification of space-designated PINGUIN used to counteract the adverse effect of long-term microgravity on the skeletal muscles and the skeleton. 30 children were investigated prior to, immediately after, and in a delayed period after this treatment. A group of 11 healthy volunteers were also investigated as their control. The program of investigation included routine stabilimetry, the station test, and head rolling tests. The results demonstrate that in healthy subjects the standing pose is primarily acquired and sustained by means of the visual analyzer, whereas the CCP patients pose could attain this pose with a significantly weakened control by the visual analyzer. Application of ADELI increases the role of visual analyzer in the control of standing pose. Following the treatment, the stabilimetric indices of patients changed for the better and approached those in healthy subjects.

Adolescent↗
PubMed1994

Suited crewmember productivity.

Analysis of the extravehicular activity (EVA) sortie experience gained in the former Soviet Union and physiologic hygienic aspect of space suit design and development shows that crewmember productivity is related to the following main factors: -space suit microclimate (gas composition, pressure and temperature); -limitation of motion activity and perception, imposed by the space suit; -good crewmember training in the ground training program; -level of crewmember general physical performance capabilities in connection with mission duration and intervals between sorties; -individual EVA experience (with accumulation) at which workmanship improves, while metabolism, physical and emotional stress decreases; -concrete EVA duration and work rate; -EVA bioengineering, including selection of tools, work station, EVA technology and mechanization.

Astronauts↗
PubMed1991

EVA medical problems.

The experience gained in the USSR allows the following conclusions: physiological responses to EVA do not depend on flight duration in qualitative and quantitative terms. Physiological responses to EVA are mainly determined by following 3 factors: physiological activities; space suit environmental parameters; physiological stress. This paper reviews problems, associated with altitude decompression sickness; thermal regulation of the body, visual function and physiological psychological stress as well as individual EVA experience in physiological responses.

Aerospace Medicine↗
PubMedDate not supplied

[Functional state of the human hearing analyzer exposed to +Gx acceleration].

The functional state of the acoustic analyzer of man was investigated during an exposure to +Gx acceleration of 4-14 g applied at an angle of 78 degrees to the long axis of the body. During an exposure to 8-10 g the hearing state began to deteriorate. This included an increase in the tonic thresholds of hearing sensitivity with respect to the aerial and bone conduction, and an increase in the differential thresholds of hearing with respect to the strength and pitch. With an increase of the acceleration value these changes grew, reaching maximum at 14 g. It is suggested that possible mechanisms of changes in the hearing sensitivity are associated with disorders in the systems of sound conveyance and perception.

Acceleration↗
PubMedDate not supplied

[Physiologo-hygienic basis for the construction of individual equipment for preventing the adverse effects of weightlessness].

In order to prevent the unfavourable effect of weightlessness, it is recommended to use individual suits for long wear. These include a preventive pressure suit which provides an axial pressure on the skeleton and moments of forces during movement, and a preventive vacuum suit which provides lower body decompression. The suits ensures the conditions for the function of the musculoskeletal apparatus and the cardiovascular system which are close to those on the Earth.

Atmospheric Pressure↗
PubMedDate not supplied

[The ergonomic aspects of space vehicle manual motion control during re-entry].

In 1960s, the Russian space program spared no resources for extensive theoretical and empiric studies of manual control by vehicles during re-entry at the second and first space speeds by cosmonauts experiencing g-loads of up to 18 g. About 6,000 static and 400 centrifuge experiments were performed, and if g-loads caused loss of vision the cosmonaut remained operational getting audible indication. Ergonomic characteristics of the control organs and indicators were high enough to guarantee accuracy despite the g-loads comparable with values under static conditions. The store of knowledge acquired in those studies does not lose significance for the present-day piloted space programs.

Equipment Design↗
PubMedDate not supplied

[Physical performance and function of the cardiorespiratory system in additional respiratory resistance].

This paper presents results of examining respiration and circulation parameters of healthy volunteers pedalling a bicycle ergometer at different degrees of inspiratory-expiratory resistance. In this situation the performance-limiting factor is an increased load on respiratory muscles. An additional signal of performance problems is respiratory discomfort. The paper gives a formula for predicting maximally allowable workloads in response to increased respiration resistance.

Adaptation, Physiological↗
PubMedDate not supplied

[Effect of increased respiratory resistance on human work capacity].

Respiratory responses to external resistive resistance are discussed, having in view data in the literature and experimental results obtained by the present authors. The adverse changes induced by this factor during muscle work are described with special emphasis on performance deterioration. Some considerations are presented which are related to the physiological implications of the maximal allowable values of respiratory resistance produced by the breathing system upon workloads of various intensity and duration.

Airway Resistance↗
PubMedDate not supplied

[Preliminary results of medical studies during the 5-month space flight aboard the "Saliut-7"--"Soiuz-T" orbital complex].

The medical examinations carried out in the 150-day flight were a continuation of the previous studies in terms of the approaches and methods used. The novel approach was a biochemical study of body fluids collected during flight. An important place was occupied by during EVA. The medical results of the 150-day flight were in consistency with the data obtained during previous space flights of similar duration. The health condition and work capacity of the crewmembers throughout the flight (including two EVA events) were good. The changes seen during and after flight were adaptive and disappeared after a relatively short readaptation period.

Carbohydrate Metabolism↗
PubMedDate not supplied

[Pharmacologic correction of the effect of cold on man].

The effect of pharmacological stimulants and prescriptions on the thermal status of man and their possible use to extend the exposure to the cold environment were investigated. The effectiveness of the following drugs and prescriptions was assessed: sydnocarb, phenamine, indopan; glutamic acid + lagochilus + ephedrine; sydnocarb + glutamic acid (sydnogluton); ephedrine + glutamic acid + strychnine. The test subjects were kept in air (in a thermal chamber) at -20 degrees C or in water at 0 to 2.5 degrees C (resting or swimming). The most effective treatment was provided by sydnocarb (effective doses were 10 mg X 2 or 30 mg X 5 in air or water, respectively) and sydnogluton (sydnocarb 30 mg + glutamic acid 0.25 g X 5 in cold water). When compared to placebo, sydnocarb (or sydnogluton) assured better thermal parameters of the body in cold water and longer (by 2-6 hrs) exposure which increased to 20 hrs.

Amphetamine↗
PubMedDate not supplied

[The concept of functional strength in the problem of establishing objective biomechanical requirements for systems to protect and rescue aircraft crews].

This paper discusses problems related to the ambiguous formulation of biomechanical requirements for the quality of protection and rescue means. In order to objectivize these requirements, it is recommended to use the functional strength concept which reflects both mechanical (with specific features characteristic of biomechanical systems taken into account) and functional results of adverse effects. The paper also describes the potential use of this parameter in developing complex requirements for various programmed and contingent situations and probability aspects of the problem of evaluating protection and rescue means.

Accidents, Aviation↗