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Biomedical subjects

S A Guliar

Publications and source records attributed to S A Guliar.

At least 19 recordsLinked to original sources
PubMedDate not supplied

[The readaptation of the respiration, blood circulation and body oxygen regimen in aquanauts after saturation dives to depths of up to 450 m].

Main trace posthyperbaric and postdecompression responses to respiration, circulation and oxygen profiles, dynamics of their reduction in 99 aquanauts at pressure of 46 kgs/cm2 (0.46 mPa) during 14-30 day period have been studied. The respiratory changes were found to be characterized by: ventilatory function disorders which followed the obstructive-restrictive pattern; discoordination of ventilation regulation and slowing down of respiratory gas transport through aerohematic barrier. The hemodynamic shifts have been manifested as cardiac rhythm instability, heart pump function followed by decreased cardiac contractions on exercise exposures. The economy and efficiency of body oxygen profiles in a respiration loop become lower than that in hemodynamic loop. The rate of the alveolar oxygen supply is decreased to the levels lower than the rates of oxygen supply by arterial and mixed venous blood. The long-term functional rearrangement of respiratory gas transport followed by the phase changes combined with the specific and nonspecific reactions persisting over a period of 30-60 days and more longer after decompression, is existed.

Adaptation, Physiological↗
PubMedDate not supplied

[Adaptive reactions in humans during repeated exposure to deep-water saturation immersion].

Evaluation of changes in respiration circulation and respiratory gas transport has shown that long-term influence of hyperbaria gives rise to phase changes and promotes a shift to a new level of the functional state of aquanauts. It is established that the postdecompression syndrome is characterized by the lability of main parameters of breathing and circulation, depression of gas exchange, disorders of bronchial permeability, relaxation of the cardiac pump function, decrease of physical workability against the background of inhibition of the adrenal cortex and weakening of the non-specific immunoresistance. Examination of 145 deep divers has revealed regularities of readaptation dynamics and has permitted a conclusion on an increase of unfavourable tendencies in the ventilatory pulmonary function and cardiac pump function under repeated effect of saturated diving. The normative values of external respiration are worked out as applied to divers. Some new approaches to the technology of medical providing of deep divings and correction of non-specific professional pathology of acquanauts are physiologically substantiated proceeding from tendencies of shifts in the periods between divings and diving norms.

Adaptation, Physiological↗
PubMedDate not supplied

[High density respiratory syndrome: I. Oscillations of flow-volume curves during forced respiration in dense gas media].

33 divers exposed to high pressure have been examined in three series. The dynamics of the forced breathing parameters has been studied: I--helio or neon-oxygen medium under pressure of 1.078-3.53 MPa (11-36 kg/m2) with density to 32.7 kg/m3; II--nitrogen-oxygen medium under 0.274-0.882 MPa (2.8-9.0 kg/m2) with density of 11.7 kg/m3; III--under the same conditions, as II, but using bronchospasmolytics (stimulators of 2-adrenoreceptors: astompent, salbutamol, berotec) under hyperbaria. A new phenomenon: high-density breathing syndrome is revealed. It includes appearance of oscillations of respiratory flows against the background of a decrease of forced breathing rate in dense gas medium and has a common mechanism of appearance both during inhale and exhale. High hydrostatic pressure and narcotic qualities of inert gases can have a modulating effect. Evidences are obtained that tremor phenomena observed during high pressure nervous syndrome can influence the biomechanics of forced breathing at hyperbaria. A high correlation between amplitude modulation of electromyograms of breathing muscles and pneumotachogram oscillations within the range, corresponding to the frequency of physiological tremor, allowed assuming that tremor of breathing muscles induced by high-density gas medium action is one of factors responsible for appearance of respiratory flows oscillations.

Adult↗
PubMedDate not supplied

[High density respiratory syndrome: II. The mechanics of forced respiration with artificial resistive load under normobaric pressure].

The dynamics of forced inhale (I series) and exhale (II series) parameters with additional external artificial resistive load was studied under normobaric conditions. The artificial resistance to breathing increased stepwise using removable diaphragms with sequential decrease of hole diameter from 25, 17, 13, 9, 7.5, 4.5 to 3 mm. While studying forced inhale the diaphragms were set up at Fleish pipe airflow input. In the case of forced inhale the diaphragms were set up at the pipe output. A phenomenon is revealed which consists in appearance of respiratory flow oscillations on the "flow-volume" curves during forced breathing with an increase of resistive load. Frequency maxima of the oscillations were located within the range of 6-15 Hz. The possible mechanisms for appearance of respiratory muscle tremor and respiratory flow oscillations are under discussion.

Adolescent↗
PubMedDate not supplied

[High density respiratory syndrome: III. The functional role of oscillation of respiratory flow during respiration in dense gas media].

It is found out that when reaching critical density of gas medium (20.4-24.0 kg/m3), the relative power of oscillations on the "flow-volume" curves and pneumotachograms sharply increases. At the same time the maximal rate of exhale, rates of expiratory flows in large bronchi decrease significantly and the rates of expiratory flows in bronchi of middle and small calibers reduce to zero. Within the range of densities of different gas medium (from 1.3 to 32.7 kg/m3) the changes in the relative power of oscillations of respiratory flows correlate well with the changes in permeability of upper respiratory tracts (r = -0.932 +/- 0.054). A regression equation describing this dependence is obtained. A detailed description is given to symptoms of high-density breathing syndrome: a decrease in rates of gas flows in tracheobronchial tree, early development of dynamic compression of airway, tremor of breathing muscles and appearance of respiratory flow oscillations, pronounced dyspnea and hypoventilation of alveoli. A hypothetic scheme of its development is presented. The functional significance of respiratory flow oscillations as a mechanism improving gas exchange in gas media with extremely high density is under discussion.

Airway Resistance↗
PubMedDate not supplied

[Continuous noninvasive recording of circulatory parameters while performing the Valsalva test under elevated ambient pressure].

The results are presented which confirm applicability of the Valsalva test as a functional exercise for the cardiovascular system while studying changes of the circulation regulation under high ambient pressure. Methods of transthoracic tetrapolar impedance plethysmography, electro- and intervalocardiography and mean arterial pressure measurement by means of the oscillometric servosystem are shown as adequate and highly informative under these conditions.

Atmospheric Pressure↗
PubMedDate not supplied

[The current concepts of the adaptation of the human body to hyperbarism and its readaptation after decompression].

The data presented in the recent literature and the authors' results allow formulating basic positions of the conception on the phase adaptation to the increased density of gas mixtures (nitrogen, helium) with complete saturation. Each of the three phases is shown to depend on the intensity of hyperbaric stress and the organism state. A hypothesis is advanced that formation of the system functional and then a structural trace in possible in response to the repeated influences of prolonged hyperbarism. Cross deadaptation and decompensation of the systems which endure the highest functional load under hyperbarism are shown to be possible. A general syndrome of high pressures which unite nerve, respiratory, circulatory and metabolic components is characterized. Phases of the readaptation period are determined. Changes in main systems depending on periods after decompression are described.

Adaptation, Physiological↗