PubMed Health⌕ Search

Biomedical subjects

V G Doroshev

Publications and source records attributed to V G Doroshev.

At least 19 recordsLinked to original sources
PubMed1994

[The dynamic circulatory reaction of pilots to the standard test].

The examination of cardiovascular system in pilots in the process of their training has shown that the Valsalva test can execute the function of a slight or strong irritant with further changes in hemodynamics, particularly in the frequency of systoles and arterial pressure. These changes are accompanied by the shifts of cardiac volume per minute from hypo to hyper reaction. A correlation was disclosed between the reaction in the frequency of systoles and cardiac volume per minute which can be studied from the point of view of adaptation of blood circulation system to the factors of physical loads.

Adult↗
PubMedDate not supplied

[Hemodynamic types in pilots and their clinical and expert-evaluation significance].

At the present time two approaches to the hemodynamics types can be distinguished in the literature: some authors maintain that they are variants of the norm, while others claim that they emerge in the course of disease. The purpose of the present investigation was to study the different viewpoints and to clarity the clinical and diagnostic role of hemodynamics types in aviation medicine. Altogether 293 pilots were examined, 49 of which were essentially healthy and 244 had various cardiovascular pathologies. It was found that the percentage ratio of the hemodynamics types in the subjects with neurocirculatory dystonia of the hypertensive type, stage I hypertensive disease, myocardiodystrophy and myocarditic myocardiosclerosis was the same (p less than 0.05) as in the healthy pilots. This indicates that hemodynamics types do not originate during disease, being rather variations of the norm. During orthostatic tests some subjects exhibited transition of one hemodynamic type to the other (e. g., hyperkinetic-to-eukinetic type transition, p less than 0.05); however, during the very first minute after exposure 90% of the subjects displayed their inherent types which pointed to their stability. Identification of the hemodynamics types in combination with measurement of central and peripheral circulation as well as bioelectric activity of the heart at rest and during orthostatic tests can improve the sensitivity of methods used to detect pathological changes at early stages and help to choose adequate rehabilitation procedures.

Adult↗
PubMedDate not supplied

[Venous pressure in the jugular vein system and the efficiency of venous return to the right heart during 120-day antiorthostatic hypokinesia].

Study of time-course variations of venous pressure in the jugular veins can be used to identify individual adaptation to prolonged head-down tilt. The method of measuring blood return to the right heart presented here can be employed to evaluate the efficacy of countermeasures during head-down tilt and to predict orthostatic tolerance after it.

Adaptation, Physiological↗
PubMedDate not supplied

[Nature of the regulation of blood circulation in pilots].

Dynamic observations over a group of pilots within a working week during three months have shown that blood pressure increases to meet the requirements via a higher cardiac output. When stresses grow and fatigue sets in, the pattern of circulation regulation changes so that elevated blood pressure is maintained due to an increased peripheral resistance. Differential approach to the pattern of blood pressure regulation makes it possible to assess the degree of circulation adaptation to various work loads.

Adult↗
PubMedDate not supplied

[Factor analysis of reactions to lower body negative pressure on the earth and during space flight].

The method of main components was used to examine separately the cosmonauts' responses to LBNP tests on the ground and in space flight. The factor structures of the ground- and flight data did not show significant differences. In both cases the first factor can be termed the factor of venous return and the second, the factor of the cardiac state. The first two factors were responsible for about 60%, and the first three factors for 76-78% of data scatter. The observation that the factor structure remains unchanged indicates that LBNP reactions in space flight can be evaluated using the criteria applied on the Earth.

Blood Pressure↗
PubMedDate not supplied

[Comparison of direct and indirect methods of determining cardiac output].

In anesthetized dogs cardiac output was measured directly (by the method of Fick and by electromagnetic flowmetry) and indirectly (by the method of Bremser-Ranke and by rheography). The measurements were carried out before and after drug tests. The absolute values of cardiac output at rest differed depending on the method used. After the drug test all the methods revealed distinctly changes in cardiac output. A good correlation between flowmetric and rheographic methods was demonstrated. In view of this, they can be recommended to be used in rapidly changing hemodynamic situations. The method of Bremser-Ranke proved more suitable for the processes developing within 30-40 sec.

Animals↗
PubMedDate not supplied

[Study of the variations in cardiovascular system indicators using the main component method].

The main component method was used to analyze measurements of cardiovascular parameters taken in 14 healthy operators at rest. The entire sample included 237 observations. Each observation was characterized by the deviation of heart rate, mean blood pressure and stroke volume from individual data points. The latter were individual mean values of the above parameters recorded during the Valsalva maneuver. The first two main components were responsible for over 77% of total variance of signs. Visual analysis of observation distribution with respect to the components revealed small group and single data points situated peripherally at a distance from the major constellation of data points. With respect to the values in these groups it can be assumed that some of them correspond to the stressed state of the cardiovascular system. Two thirds of data points in the stressed groups are associated with the subjects who show a weak reaction to the Valsalva maneuver and one third corresponds to the true stressed state. Taking into account the Valsalva maneuver, the deviations from individual data points can be used to identify the stressed state of the cardiovascular system in healthy men at rest.

Blood Pressure↗
PubMedDate not supplied

[Dynamics of the blood circulatory indices in the crew of the Saliut space station in a functional test under physical load].

On the 4th, 9th, 16th and 21st days of the "Salyut" mission the crewmembers performed exercises with a load of about 1100 kgm. The results were compared with those obtained on the Earth. Immediately after the tests the crewmembers showed an increased heart rate and greater changes in the diastolic and pulse pressure, cardiac output and left ventricular ejection time. The above parameters returned to the normal at a slower rate. A comparison of the values recorded on different flight days did not demonstrate a distinct correlation between the changes and time of the weightlessness exposure.

Blood Circulation↗
PubMedDate not supplied

[Changes in cardiac output and orthostatic tolerance of astronauts].

Examinations of 14 cosmonauts who performed orbital flights of 14 to 175 days were used to correlate cardiac output (CO) inflight with orthostatic tolerance and LBNP reactions postflight. In 3 crewmembers CO was lower than or close to the preflight level. In 4 cosmonauts CO was higher thant preflight. The remaining 7 crewmembers showed lower orthostatic tolerance and stronger LBNP reactions. The difference between mean CO values before and during flight was in negative correlation with orthostatic tolerance (r = -0.6) and in positive correlation with LBNP reactions (r = 0.7). The correlation coefficients were derived from small samples but an identical relationship between the two different tests with inflight CO variations gives evidence that such a relationship actually exists.

Adaptation, Physiological↗
PubMedDate not supplied

[Hemodynamic and cardiac cycle phase structure study of the Saliut-4 crew].

The paper gives the results of physical examinations of P.I. Klimuk and V.I. Sevastyanov during their flight aboard the orbital station Salyut-4. The examinations were carried out by means of the Polynomial-2 device at rest and under the conditions approximating basal metabolism. Since the end of the first flight week the circulation parameters did not differ substantially from the preflight values. Stroke volume and cardiac output increased slightly. In weightlessness circulation parameters varied with respect to the work done by the cosmonauts. On the first postflight day peripheral resistance, arterial pressure and cardiac output were increased.

Blood Pressure↗
PubMedDate not supplied

[Comparative evaluation of the circulatory reaction during work in weightlessness and in the mockup of the Saliut station].

Comparative evaluations of circulation responses of 22 operators and 13 cosmonauts to simulated and real flights onboard Salyut station revealed significant differences. By the end of flight cardiovascular responses of the operators showed signs of their increased conditioning, whereas the cosmonauts exhibited symptoms of circulation tension, which were particularly expressed during the first week and by the end of flight. Operators' activities in an orbital station mockup cannot be considered an adequate model for cardiovascular studies.

Blood Circulation↗