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Biomedical subjects

N M Krivitskiĭ

Publications and source records attributed to N M Krivitskiĭ.

16 recordsLinked to original sources
PubMed1991

[Effects of volume and rate of blood loss on indicators of auto-hemodilution].

The results of synchronous monitoring of blood impedance versus body impedance in dog experiments showed that the speed of physiological hemodilution related to blood loss up to 30 ml/kg is poorly dependent on the rate of blood loss (0.4-1.0 ml/kg/min) and averages 0.186 +/- 0.02 ml/min/kg. Termination of blood loss is followed by marked reduction in the rate of auto-hemodilution. In bloodletting the studies revealed a linear dependence between the volume of blood loss up to 30 ml/kg and tissue fluid volume entering the blood stream. In blood loss intestinal absorption of fluid does not block the fluid introduction from the interstice. When associated, both these flows increase volume of fluid filling vascular bed and promote stable recovery of the baseline circulating blood volume.

Animals↗
PubMed1990

[Possibilities of the method of dilution of electro-impedance indicators in the assessment of volume dynamics of extravascular lung fluid in intensive care and resuscitation units].

The possibility of using impedance plethysmography to assess changes in the volume of the extravascular lung fluid in intensive therapy and resuscitation patients is discussed. Changes in the volume of the fluid during extracorporeal detoxication are analysed. A correlation was found between these changes and lung distensibility (r = -0.7). A significant diminution of the fluid volume was observed in response to therapeutic doses of Lasix and Nitroglycerin. Data are cited on the increasing (85 percent) volumes of the fluid in preclinical pulmonary edema in patients with left ventricular insufficiency.

Body Fluids↗
PubMed1990

[Assessment of fluid balance and several hemodynamic parameters in lung surgery using the method of impedance plethysmography].

The hemodynamic effects of different modes of controlled ventilation (CV) were studied by means of impedance plethysmography in 52 anesthetized patients during surgery on the lungs, trachea, and bronchi. To adapt this investigation technique to the conditions of the operating room, a specially designed device was applied for extracorporeal measurement of electric resistance of the blood flow. It was found that impaired transcapillary exchange of fluid in the lungs and its accumulation in the interstitial spaces were secondary to the operated lung collapse irrespective of the composition of the inhaled gas mixture used for the controlled ventilation of the contralateral lung. A differential approach to the ventilation of the dependent and independent lungs using the conventional and high-frequency CV modifications allows for an optimal compensation for the damaged transcapillary exchange of fluids in the lungs, is most physiological, sparing, and organ-saving.

Body Fluids↗
PubMed1990

[The first experience with clinical use of monocuspid xenopericardial transplants].

The article discusses experience in radical correction of Fallot's tetrad with hypoplasia of the pulmonary trunk in 43 patients by means of plastics with monocuspid xenopericardial grafts (MXG). Their processing was based on enzymatic chemical treatment of the xenopericardium. The function of the MXG was evaluated with quantitative registration of regurgitation by the method of dilution of electroimpedence indicators. Mortality in the group of patients with MXG was 8.0%, which did not differ from that in the group of patients with satisfactorily developed pulmonary trunk and its branches, and characterized the promising character of the use of this method of pulmonary trunk plastics.

Adolescent↗
PubMed1989

[Study of parameters of central hemodynamics in patients during hemodialysis].

The article discusses the results of study of the cardiac output (CO) and circulation blood volume (CBV) in patients at the beginning and end of hemodialysis. The dynamics of changes of these parameters during hemodialysis was studied in 31 patients (42 sessions). The CO and CBV reduced significantly. In a group of 10 patients who felt worse, the CO reduced by more than 30 per cent in 7, the CBV diminished by 25 and 30 per cent in 2, and CBV and CO reduced by more than 30 per cent in 1 patient in relation to the initial level. The CO and CBV were measured by means of the method of dilution of electroimpedance indicators.

Blood Volume↗
PubMedDate not supplied

[The electrical impedance indicator dilution method in studying the basic hemodynamic parameters during dialysis].

The procedure for measuring cardiac output and circulating blood volume is based on blood ability to modify its electrical conductance due to the amount of introduced ions (0.9% sodium chloride solution) or undissociated molecules (5% glucose solution). The cardiac output and circulating blood volume were calculated after measuring an area under the electrical impedance indicator dilution curve using the given formulas. With the described and thermodilution methods, the cardiac output was compared (r = 0.95). The correlation factor with the radioisotopic method in measuring the circulating blood volume was 0.88. Clinical investigations carried out in 47 patients on a programmed hemodialysis showed a significant decrease in cardiac output approximately by 700 ml/mi (7.9%) and circulating blood volume by an average of 900 ml (15.2%) by the end of a hemodialysis session, the rate of the circulating blood volume to body weight being also decreased. There was a predominant fluid "release" from the vascular bed.

Blood Volume↗
PubMedDate not supplied

[The use of a vitamin and metabolite complex for correcting the disorders in systemic and organ hemodynamics during liver resection under conditions of acute blood loss].

The efficacy of some infusion media, vitamins, and metabolites in resection of the liver in acute blood loss was studied in experiments on dogs. Inclusion of vitamins B1, B2, and B6, lipoic acid, calcium pantothenate, nicotinamide, solution of alpha-glutamate and gamma-aminobutyric acid (aminalone) in the infusion led to a sharp increase of myocardial contractility, increase of cardiac output and total hepatic blood flow, normalization of biochemical blood values, and restoration of the activity of hepatocyte enzymes.

Acute Disease↗
PubMedDate not supplied

[Determination of hemodynamic parameters by blood electrical resistance using a dilution method].

The theoretical basis and the experimental data of the hemodynamic parameter determination method have been described. The cardiac output and the circulating blood volume have been determined using intravenous injections of two solutions with different electrical resistance. A formula for blood electrical resistance was proposed. Tolerances for isoosmotic solutions were made. A system of three equations was made up on the basis of the results of two injections of solutions with different electrical conductance. From these equations blood characteristics, cardiac and circulating blood volumes can be obtained. Isoosmotic solutions of glucose and sodium chloride were used as indicators in treadmill tests with circulating blood. The measurement error practically didn't depend on the electrode type (either along or across the flow).

Blood Physiological Phenomena↗
PubMedDate not supplied

[Determination of the volume of extravascular fluid in the lungs by blood electrical resistance using a dilution method].

The theoretical basis of the method determining the volume of the extravascular lung fluid has been considered. The fluid volume is found by measuring the volume of water passing from the lung into the blood through the hyperosmotic indicator. The water volume is determined by comparing the curves of electrical resistance obtained as a result of intravenous injections of isoosmotic and hyperosmotic solutions. The electrical resistance of the blood is measured in the arterial bed. The lung fluid volume can be calculated using the parameters of the dilution curves and the equation for the crossing point.

Blood Physiological Phenomena↗
PubMedDate not supplied

[Quantitative evaluation of pulsatile flow in the extremities using a rheographic method].

A model of a limb part represented as a multilayer cylindrical conduction section is considered. The impedance is measured by means of four electrodes, and the exact and approximate expressions for the impedance are derived. With the expressions, one can calculate the value of the pulse blood flow. Various factors affecting the measurement accuracy such as skin conditions, local depths of major vessels, and relative electrode positions are analyzed. Recommendations for the choice of the electrode spacing are given to calculate the pulse and specific blood flow depending upon dimensions of the body part under study, the accuracy being not less than the preset value.

Extremities↗