[Electroimpedance Methods of Investigation of Cardiac Activity].

AIM: of the present work was assessment of possibility to use modern electroimpedace methods for the study of activity of the heart. Electroimpemdace methods of measurement for many years remained in the shadow of other diagnostic methods because of low accuracy in evaluation of various parameters. At present, there are technologies of measurement which allow to carry out electroimpedance investigations of cardiac activity dynamically and with acceptable accuracy. In this article, we present methods of electroimpedace measurements created in Institute of Biomedical Equipment of N.E. Bauman Technical University. These methods allow to assess dynamics of movement of ventricles of the heart, to evaluate volume parameters of cardiac activity and all temporal phases of activity of cardiac chambers. We also present data of studies on healthy volunteers and patients of cardiological profile. It has been shown that patients with atrial fibrillation have substantially increased duration of electrical and mechanical activity of atria and ventricles as well as lowed ejection fraction compared with other participants of experiments.

[The mechanisms of hemodynamic shifts in normovolemic hemodilution]. / Mekhanizmy gemodinamicheskikh sdvigov pri normovolemicheskoi gemodiliutsii.

Normovolemic hemodilution is shown to activate adaptation mechanisms of the heart, regional circulation and microvasculature. This is accompanied by a decline in the total peripheral resistance, an increase in venous return and intensification of the regional tissue blood flow. An increase in the cardiac output is due to mobilization of the functional cardiac reserve and is not accompanied by intensification of the heart work. Accelerated pulmonary circulation in normovolemic hemodilution may lead to functional shunting and blood oxygenation disturbances in patients with anatomic and functional respiratory changes.

[Index of microcirculatory changes in experimental dehydration in animals]. / Ob indekse izmenenii mikrotsirkuliatsii pri éksperimental'nom obezbozhivanii zhivotnykh.

On the basis of morphokinetic synthesis principles the method of determination of summarizing criterion of microcirculatory system changes was developed. It consists of marked characteristics of changes of a number of the most important morphofunctional phenomena of each of this system compartments -- interstitial, lymphatic, blood and cellular -- with their successive summation to obtain the systemic microcirculation index. The experimental dehydration in rats being a model has shown that systemic microcirculatory index was 2 times as large in 3 days of dehydration, more than 3 times -- in 6 days, and 4, 5 times -- in 12 days. In the initial stage of the experiments maximal changes were found in interstitial compartment of the microcirculatory system. The intermediate period of dehydration differed by predominant changes of vascular compartment when the lymphatic phenomena were more evident than the hemomicrocirculatory ones. In the later stage of dehydration the cellular component changes of tissues and organs were predominant.

[Systemic and organic changes in the microcirculatory bed in experimental dehydration of the body]. / Sistemnye i organnye izmeneniia mikrotsirkuliarnogo rusla pri éksperimenta'lnoi degidratsii organizma.

Among systemic mechanisms of microvascular reactivity of the musculus spinotrapezius, pancreas and small intestine mesentery at dehydration, a special role play the changes directed to maintenance of harmony between the capacity of the blood bed and volume of the circulatory blood, morpho-functional factors on regulation of hemodynamics, as well as mechanism of liquor resource++ elimination from the blood bed. The organic peculiarities of the microvascular reactivity at dehydration are determined by topic and quantitative character of their changes.

[Comparative evaluation of the adaptive mechanisms of the microcirculatory bed during dehydration]. / Sravnitel'naia otsenka mekhanizmov adaptatsii mikrotsirkuliatornogo rusla pri obezvozhivanii.

In total preparations of the white rat small intestine mesentery, impregnated with silver nitrate, as well as under conditions of vital microscopical observations at certain stages of alimentary experimental dehydration, analogous changes in the microcirculatory bed links have been demonstrated. Comparison of quantitative parameters in decreasing diameters of the microvessels, specific for dehydrated preparations has shown a great importance of these changes in the impregnated preparations at the expense of tissue condensation at their histological treatment. The advantages of a complex application of both methods for estimating dynamics of vascular, intervascular and extravascular changes are proved.

[Correction of disorders in the microcirculatory system in embolism of the aortic bifurcation and major arteries of the extremities]. / Korrektsiia narushenii, voznikaiushchikh v sisteme mikrotsirkuliatsii pri embolii bifurkatsii aorty i magistral'nykh arterii konechnostei.

A favorable effect of combined pathogenetic treatment for acute arterial obstruction on systemic microcirculation has been demonstrated in 40 experimental animals and 40 patients operated on for embolism in the aortic bifurcation and main arteries of the limbs.

[Effect of controlled normovolemic hemodilution on the microcirculatory bed and the incidence of postoperative complications in abdominal surgery]. / Vliianie napravlennoi normovolemicheskoi gemodiliutsii na mikrotsirkuliatornoe ruslo i chastotu posleoperatsionnykh oslozhnenii v abdominal'noi khirurgii.

Directed normovolemic hemodilution with the preoperative reservation of part of the patients' blood considerably reduced the pathologic effect of the operative aggression on the microcirculation system, allowed reduction of the frequency of postoperative complications and increased the efficiency of treatment of 93 patients with diseases of organs of the abdominal cavity.

[Reactivity of the microcirculation bed of the small intestine mesentery in experimental dehydration in rats]. / Reaktivnost' mikrotsirkuliatornogo rusla bryzheiki tonkoi kishki pri éksperimental'noi degidratatsii u krys.

The state of mesenteric microcirculatory bed has been studied in male rats 3, 6 and 12 days after the beginning of alimentary dehydration. It has been revealed that vascular, intravascular and extravascular changes were of particular importance. Spastic reactions of arterioles and precapillary arterioles, the activation of arteriolo-venular shunting and the reduction in capillary circulation accompanied by diminution of all microvascular diameters were among the most marked vascular phenomena. The intravascular changes were represented by decreased blood flow rate, erythrocyte aggregation and leucocyte adhesion. The extravascular phenomena were characterized by the appearance of local hemorrhages.

[Results and prospects for the study of the morphologic basis of microcirculation of the blood]. / Itogi i perspektivy izucheniia morfologicheskikh osnov gemomikrotsirkuliatsii.

The survey of the works, performed during the 11th five-year period in studying general biological regularities of microcirculation, demonstrates certain success in investigations developed in the following directions: functional geometry of the hemo-microcirculatory bed; elaboration of quantitative and qualitative analysis methods of the microcirculatory system elements; functional morphology of the vascular endothelium; experimental analysis of adaptive mechanisms of the microcirculatory bed; clinical-morphological investigations of microcirculation. Formation of structural-functional units, ensuring specialization of microcirculation in organs, forms the base of the functional geometry of the microcirculatory bed. This makes necessary conditions for compartmentalization of some micro-region in an organ and spatial distribution of various liquid media in dependence of certain topology of microvessels. The most perspective ways in development of morphological investigations, concerning the general biological regularities of microcirculation, are discussed.

[Comparative morphometry of vessels of the microcirculatory bed of the cat pericardium in impregnated preparations and during in vivo microscopy]. / Sravnitel'naia morfometriia sosudov mikrotsirkuliatornogo rusla perikarda koshki na impregnirovannykh preparatakh i pri vital'noi mikroskopii.

In impregnated (with silver nitrate) preparations of the cat pericardium and in photonegative pericardial microvessels photographed in vital experiments, diameters of the main vascular groups in the microcirculatory bed (arterioles, precapillaries, capillaries, postcapillaries and venules) were comparatively estimated. When impregnated, the vascular diameter decreases; the degree of the changes is not equal and depends on the wall structure. Therefore, when studying impregnated preparations, it is necessary to introduce the correction coefficients in order to make the data obtained comparable with the vital ones.

[Functional and morphological basis for the nature of the microcirculatory bed reactions of the bulbar conjunctiva in experimental occlusion of the cranial mesenteric artery]. / Funktsional'no-morfologicheskoe obosnovanie kharaktera reaktsii mikrotsirkuliatornogo rusla bul'barnoi kon''iuntivy pri éksperimental'noi okkliuzii kranial'noi bryzheechnoi arterii.

A complex analysis on changes occurring in conjunctival microcirculation and a number of indices of hemodynamics, hemorheology and metabolism at different time of experimental occlusion in the cranial mesenteric artery has demonstrated certain objective and many-sided correlations that prove a systemic character of biomicroscopical changes in the conjunctiva. The degree of changes in the conjunctival microcirculation depends on duration of occlusion. After a 3 hours' occlusion revascularization is accompanied by reversible general microcirculatory disorders that are registered in bulboconjunctiva. In a 6 and 12 hours' occlusion revascularization is characterized by increasing general changes in microcirculation.

[State of the microcirculatory bed of the mesentery in experimental dehydration]. / Sostoianie mikrotsirkuliatornogo rusla bryzheiki pri éksperimental'nom degidratsii.

The results of a complex functional-morphological analysis on the state of the mesentric microcirculatory bed have demonstrated a peculiar dynamics in increasing changes of its blood and lymphatic segments. Their degree depends on the stage of dehydration. On the 3d day, the changes revealed are not great and are of redistributive character. On the 6th day dehydration aquires the maximal intensity of changes in vessels and hemodynamics. By the 10th day, maximal level of vascular, intravascular and hemodynamic disorders is evident. Comparing these data and the results of investigations on intracellular and extracellular ion contents, it is possible to suggest a definite staged water elimination from the main depots of the organism. The reserves of extracellular water section are the first to be mobilized at the expense of its interstitial and transcellular links. On the 6th day of the experiment maximal intensity of blood and lymphatic dehydration is noted. Final stages of dehydration are characterized by a pronounced cellular dehydration.

[Structure and development of the microcirculatory bed of the pleural villi in man and animals]. / O stroenii i razvitii mikrotsirkuliatornogo rusla plevral'nykh vorsin cheloveka i zhivotnykh.

The structure of the microcirculatory bed in the pleural villi was studied by the method of impregnation with silver nitrate, after V.V. Kuprianov. In human and animal mediastinal pleura, the microcirculatory ways are regulated within polymerously repeated complexes--moduli. A characteristic feature of the pleural villi blood supply is the presence of capillary glomeruli with a vascular peduncle consisting of an arteriole and a venule. Four types of structure are revealed in the vascular peduncle consisting of an arteriole and a venule. Four types of structure are revealed in the vascular peduncle of the pleural villi. They were studied morphometrically. Correlation in the development of the villi microcirculatory bed and that of the vascular peduncle was stated. Participation of villous vessels in the regulation of fluid balance in the pleural cavity was discussed.

[Methods of intravital study of the microcirculatory bed and assessment of vital dye transport in the pericardium]. / Metody prizhiznennogo izucheniia mikrotsirkuliatornogo rusla i otsenki transporta vital, nogo krasitelia v perikarde.

The method of vital microscopy was used to obtain new data on the features of blood microcirculation in different links of the vascular bed in the pericardium. The work of dynamic structures of microcirculation pathways controlling processes of redistribution of blood streams is shown such as arteriolar anastomoses, zones of branching of resistance microvessels, the pathways of magistralization of the capillary blood stream, venular anastomoses and microvalves. By means of calorimetric study of the serous fluid obtained from the pericardium cavity, after a preliminary intravenous injection of the vital dye a quantitative evaluation of the transcapillary transport of the dye was made under conditions of a normal and altered permiability.