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Biomedical subjects

I N Cherniakov

Publications and source records attributed to I N Cherniakov.

52 records · Page 3Linked to original sources
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[Hypobaric nitrogen-oxygen atmosphere as a method of preventing altitude decompression sickness].

It has been shown experimentally that the development of altitude decompression disease at 250 and 180 mm Hg can be prevented by preliminary desaturation in the nitrogen-oxygen hypobaric atmosphere (60% N2 and 40% O2 at 550 mm Hg). This has been demonstrated in 38 experiments on 21 test subjects. The use of this atmosphere in space cabin prevents the development of decompression disease upon a decrease of the cabin pressure to 250 mm Hg and upon extravehicular activity in a space suit with 180--200 mm Hg.

Adult↗
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[Effect on humans and animals of multiple exposures to rarefied atmospheres].

In order to study the chronic form of decompression disease, clinical and physiological examinations of 38 test subjects were carried out. They participated in 133 chamber experiments and were exposed to an altitude of 11,000--12,000 m for 2--3 to 20--24 hours after desaturation of different duration. Besides, histological and histochemical examinations of organs and tissues of 3 dogs were performed. During 70, 110 and 140 days the dogs were exposed 20, 33 and 35 times to an altitude of 12,000 m for 2--2.5 hours without preliminary desaturation. No persistent pathological changes were found in the animal or human body.

Adult↗
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[Effectiveness of hyperbaric oxygenation as a factor of increasing the resistance of the human body to space flight conditions].

In four experimental runs (30 test subjects in 407 tests), the beneficial effect of hyperbaric oxygenation (HBO) on flight tolerance was demonstrated. HBO sessions (7-8 sessions of an hour in duration during 10-12 days at pO2 = 2 atm) helped subjects with poor altitude tolerance to increase the altitude ceiling by 1 km and reserve time at altitudes of 6-7 km by 3-4 min, the effect being persistent for 2-3 months. Statokinetic tolerance of subjects with medium motion sickness susceptibility grew by 2-2.5 times after the above HBO sessions. As compared to regular rest, the HBO treatment shortened two-fold the period of recovery of the health state and work capacity of operators, which went down during flight, and increased 15-20% the time of repeated work prior to failure in a stressful environment.

Adult↗
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[Possibility of conserving the heat balance of the human organism in an extremely rarefied atmosphere by vacuum evaporation of sweat from the surface of the body].

As a result of 64 experiments carried out on 24 test subjects, it has been shown that extreme overwarming due to moderate and heavy thermal loads can be prevented with the aid of heat release through sweat evaporation from the surface of the body under the action of a rarefied atmosphere (termed vacuum sweat evaporation). The test subjects wearing altitude suits remained in a thermal altitude chamber at 40 and 55 degrees C for 8 to 3 hours at rest and doing light work at altitudes of 7 to 25 km without marked signs of overwarming. The entire heat release occurred only through vacuum sweat evaporation from the surface of the body that was under the altitude suit during a gradual decrease of the chamber pressure to 20 mm Hg (equivalent to an altitude of 25 km). The findings give support to the hypothesis that heart release via vacuum sweat evaporation from the surface of the body can be used as a method of controlling thermal homeostasis during high altitude and space flights.

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[Probability of altitude decompression sickness during a suited exit from a space ship having a near-Earth atmosphere].

A large number (550) pressure chamber experiments in which 200 suited subjects simulated an egress from the spacecraft (decompression from 760 to 20--10 mm Hg) showed a relationship between decompression sickness frequency and severity, space suit absolute pressure (160--310 mm Hg), time of the exposure (1--10 hours) and desaturation (15--60 min), and exercise load (150--400 Cal/hr). Without desaturation there were no decompression sickness symptoms at a suit pressure of 270--310 mm Hg. An egress into space in a suit at a pressure of 160--230 mm Hg after 15--60 min desaturation induced bends of different severity. Less frequent cases of decompression sickness in our experiments as compared with the literature data (obtained on unsuited subjects) can be attributed to the peculiar kinematics of movements and excessive pressure in the suit.

Adult↗
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[Characteristics of human external respiration under excess intrapulmonary pressure under sea level and "altitude" conditions according to pneumotachographic data].

In 54 pressure chamber experiments 12 healthy male test subjects took part. Their pneumotachograms and other physiological parameters at a positive pressure breathing of 30 mm Hg at sea level and of 125--130 mm Hg at an altitude of 25,000 m at rest and while exercising were recorded. High altitude facilities and pneumotachograph were modified to meet the experimental requirements. The changes in pneumotachographic readings depended on the excess intrapulmonary pressure, its variations with respect to the respiratory stages, efficiency of the external counterpressure on the body, as well as motor activity of the test subjects. The pneumotachographic procedure allows qualitative and quantitative evaluations of external respiration upon excess intrapulmonary pressure, and study of the mechanism of these changes supported by other physiological methods.

Adult↗
PubMedDate not supplied

[Prevention of altitude decompression sickness during short flights in a depressurized cabin at high altitudes].

Forty altitude chamber experiments were carried out in which 18 test subjects participated. The purpose of the experiments was to prevent decompression sickness in a pilot using an altitude compensatory suit and oxygen mask. It was demonstrated that oxygen breathing on the ground and at an altitude of 8 km for 20 and 50-60 min eliminated severe symptoms and lowered the frequency of occurrence of mild symptoms of decompression sickness during the subsequent 10-20 and 60-120 min exposures to altitudes of 40,000 and 11,000 m respectively. An increase in the absolute pressure to 240-290 mm Hg in the altitude garment prevented decompression sickness of altitudes of 11,000-15,000 m and eliminated it if it occurred at lower barometric pressure.

Adult↗
PubMedDate not supplied

[Prevention of decompression sickness as applied to conditions of multiple space walks].

Six 3-day experiments were carried out in an altitude chamber in which 6 test subjects took part. The experiments simulated repeated extra-vehicular activities--intensive work at an altitude of 10,000 m in a helmet or at an altitude of 40,000 m on a space suit pressurized at 200 mm Hg. It was demonstrated that altitude decompression could be prevented by desaturation--prolonged exposure to the hypobaric atmosphere (430 mm Hg) and 100% O2 or a 40% O2 and 60% N2 mixture. During the 3-day experiment the test subjects made seven 3--4 hour excursions, showing no symptoms of decompression disease.

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