SU1291871A1 - Method of analyzing pulmonary hemodynamics - Google Patents

Abstract

The invention relates to medical research methods, in particular to methods for studying hemodynamics of the lungs, based on the measurement of electrical resistance (ES). The purpose of the invention is to increase the information content of the research method. To do this, along with the determination of the boundaries of the skin projection of the organ, the measurement of the ES part of the body by the tetrapolar method and the blood resistance in the sample, further determine the thickness of the tissues covering the organ (for example, ultrasound echalocation). Then, starting from the thickness of the layer, the distance between the centers of the electrodes is set to not more than 1.5 times the thickness of the layer of tissues, ensuring the passage of electrical current. Conduct no less than one measurement of the base resistance and its pulse increment. The specific electrical conduction of blood is determined in the electrolytic cell and the hemodynamic state is estimated from the data obtained, the blood flow, blood filling and air content in the studied part of the lungs are determined by the formulas. about tp (L SO eo 4J

Description

112

This invention relates to medical research methods, in particular to methods for studying hemodynamics of the lungs, based on the measurement of electrical resistance.

The purpose of the invention is to increase the information content of the research method.

The method is carried out as follows.

Along with defining the boundaries of the skin projection of the organ, measuring the electrical resistance of a part of the body by the tetrapolar method and the blood resistance in the sample, the thickness of the tissue covering the organ is also determined (for example, by ultrasonic echolocation). Then, based on the thickness of the layer, the appropriate interelectrode distances are chosen to ensure the passage of electric current: the thickness of the layer of tissues covering the organ and at the same time in the covering layer and the organ. For measuring resistance in the covering layer, the distance between the electrodes should be no more than 1.5 thick. this layer, with electrodes - radius; not more than 0.2 cm. When measuring resistance simultaneously in a tissue layer of an organ, the distance between the electrodes should be at least 6 times the thickness of the tissue covering the organ, and the radius of the electrodes should not be more than 0.4 cm. Under these conditions, not less than one measurement is taken, the base resistance and its pulse increment. The conductivity of blood is determined in an electrolytic cell and the hemodynamic state is assessed according to the data obtained, the blood flow, blood supply and air content in the test portion are determined by the formulas

to their.

Example. In the test man, the borders of the right lung are determined by percussion — the maximum length of the skin projection of the organ along the median axillary line is 28 cm. -an ultrasonic signal cell, which determines the thickness of the chest (h 1.6 cm).

12

To measure the resistance only in the layer of tissues covering the organ, the distance between the outermost (current-carrying) electrodes is 2.5 cm. All four electrodes are placed along the midaxial line with the center of the electrode installation, which falls on the fifth intercostal space. Hemispherical electrodes with a radius of 0.2 cm made of stainless steel are placed on a rigid dielectric holder. The skin under the electrodes is pretreated with alcohol and saline. The basic electrical resistance is measured on a modified reoplethysmograph (R. 45 ohms). With a distance between the current electrodes of 12 cm and the potential electrodes of 4 cm, the basis resistance (Rj 29 ohms) is also measured. Using the recorder, the corresponding pulse increments of UR are recorded, and uR. Blood is taken (3.5 cmM from a vein into a syringe containing one drop of heparin solution. The measured electrical resistance of the blood and reduced to body temperature are converted to specific (180 Ohm cm). Recalculate all measured electrical resistances in specific conductivities taking into account the coefficients determined by the interelectrode distances.

The conductivity of the lung is found by the equation

f +

with

to

ti-i

(

l ((i

((

7

where K is the reflection coefficient;

 - distance from the center of the electrode unit to the current-carrying electrodes; A - distance from center

electrode installation to potential electrodes. The differential is the equation, find the value of y.

By magnitude, dy, y | and the coefficients depending on the structure of the lungs (form factor) and frequency of the probing current are found per 100 cm of the volume of the organ; the value of the pulse increment of the volume of blood in the lungs

1.5 volume

Have

to

(PP)

to ,, 1.00 about, 245 and

PP 1.9

Ay ..- Kj UK

; 100 2.01 ml

where Q is the ratio of the electrical equivalents of the stroke volume and the pulse volume increment

blood, minute volume of blood circulation

.P 133 ml / min, where P - pulse rate;

and the amount of hindrance

relative bloodstream 1,5-f UK

100 16.9 ml.

Claims (1)

Claim 20 Method of hemodynamic study. of the lungs by defining the boundaries of the skin. Editor I. Derbak Order 225/42 Compiled by E. Kolmakova Tehred L.Oleynik Proofreader C, Shekmar. Circulation 777 Subscription VNISh State Committee of the USSR for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., d. 4/5 Production and printing company, Uzhgorod, st. Project, 4 JO 15 20 . the projection of the organ, the imposition of electrodes, the measurement of the electrical resistance and the specific resistance of the blood, and the fact that, in order to increase the information content of the method, determine the thickness of the layer, the tissues covering the organ, then set the distance between the centers of the electrodes are not more than 1.5 times the thickness of the tissue layer, the resistance in this layer is measured, then at a distance between electrodes equal to 6 times the thickness of the layer, the resistance is measured simultaneously in the tissue layer and organ, the radii of the electrodes when measuring resistance no more than 0.2 cm in the tissue layer, and when measuring in the tissue layer and organ no more than 0.4 cm, after which the pulse increment of blood quantity, impact release, blood filling, and the air content and their value are estimated hemodynamics in the lungs.