RU2619752C1 - Method for bladder fullness diagnosis - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: electrodes are applied to the skin in the bladder location area. They are connected to a bioelectric potentials amplifier to obtain two leads which measure bioelectrical activity signals of the bladder walls. Electrocardiograms are recorded simultaneously for signal filtering. The received signals are mathematically processed by normalizing and plotting of bladder and electrocardiogram signals spectra by the Fourier method. The bladder signal is filtered from the electrocardiogram signal by bladder signal spectrum division by the electrocardiogram signal spectrum. Characteristic spectra frequencies are selected from the most active range of 0.7 Hz, 1.5 Hz, 1.7 Hz. The said measurement is performed twice - before and after a water-drinking stress. The characteristic frequencies amplitudes are compared, and bladder fullness is judged by the degree of their increase.

EFFECT: method allows accurate, simple and non-invasive determination of bladder fullness due to the simultaneous recording of bladder wall bioelectrical activity and electrocardiogram signal, followed by bladder signal filtration from the electrocardiogram signal.

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Description

The invention relates to the field of medicine and biophysics, can be used in nephrology to assess fullness, contractility, as well as hyperactivity of the bladder.

A known method of indicating the level of fullness of the bladder (MP) based on the frequency of oscillations of the MP (see patent for invention US2013289446 (A1) - Bladder Fullness Level Indication Based on Bladder Oscillation Frequency, IPC A61B5 / 00; A61B5 / 11; A61B5 / 20; A61B7 / 00; A61N1 / 05; A61N1 / 36). This diagnostic system includes an implantable sensor, which can detect mechanical vibrations from the MP that occur during the filling of the MP. The completeness level of a patient’s MP can be determined based on the frequency of mechanical vibrations in the patient’s MP. The bladder may fluctuate mechanically in response to non-urinary contractions of the patient's MP. The frequency at which the bladder fluctuates may correlate with the level of fullness of the bladder. In some examples, the medical device may be configured to control the delivery of electrical stimulation to a patient based on the frequency of oscillation in the bladder. In addition, in order to control therapy based on the oscillation frequency of the bladder, patient notifications can be generated (for example, automatically by the processor of the device) based on the oscillation frequency of the MP. The disadvantage of this method is the invasiveness of this diagnostic method, including the implantation of the device into the patient’s body.

A control device for preventing urinary incontinence is known, which is based on measuring the electrical impedance of the MP, which records both the volume of urine and the degree of compression and expansion of the MP associated with respiration. It includes a pair of electrodes attached to the surface of the body that supply high-frequency alternating current, and a pair of sensor electrodes located also on the skin in the region of the magnetic field (between sources), which detect a change in the impedance between them (see patent for US5103835 (A ) - Impedance monitoring device for preventing urinary incontinence. IPC A61B5 / 20; A61F5 / 37; A61F5 / 44; A61F5 / 48; A61N1 / 36). The disadvantage of this device is that it is sensitive to interference that occurs during movements. It requires additional calibration for upright position.

A known method of measuring the level of MP filling with a system that records the resistance of the MP between two electrodes that are implanted in appropriate places near the wall of the bladder, located opposite each other with respect to the center of the bladder. At least one of the electrodes receives an electrical signal emitted by the other electrode, thus measuring the impedance (see patent for invention US2007100387 (A1) - Impedance-based bladdersensing, IPC A61N1 / 32). The disadvantage of this method is its invasiveness, which increases the risk of inflammatory processes both in the areas of damage to the skin and in the field of implantation of the electrodes.

The prototype of the proposed method is a method and device for controlling the level of MP filling in a patient, based on measuring the impedance between at least two pairs of electrodes located on the surface of the patient’s body around the MP. In this case, an alternating voltage is supplied to at least one of the electrodes in pairs. In this way, the volume of the magnetic field is measured by measuring changes in the impedance between the electrodes (see WO2013013782 (A2) - METHOD AND DEVICE FOR MONITORING THE FILLING LEVEL OF THE BLADDER OF A PATIENT, IPC A61B5 / 053; A61B5 / 20). This method is partially invasive, since it requires the introduction of at least one electrode into the human abdomen. The disadvantage of this method is its sensitivity to human movement during the study: the patient must be in a stationary position during the study. Also, inconvenience can be caused to the patient during the procedure due to the need to enter the electrode into the body.

The objective of the proposed method is a non-invasive study of the biopotentials of the bladder (MP), depending on its fullness.

The technical result consists in simplifying the method for diagnosing MP due to the lack of the need to measure the biopotentials of MP invasively from the walls of the MP, reducing interference and improving the accuracy of the measurement by filtering the electrocardiographic signal.

The specified technical result is achieved by the fact that during the study the test subject was placed in a comfortable position on a chair, three electrodes of electroencephalograph leads were placed on the skin in the area of the bladder (MP). For this study, electrodes of the chest leads were used. One of the electrodes was indifferent. Thus, two leads were obtained for registering bladder microwaves (biopotentials). At the same time, a signal of one electrocardiographic lead was recorded. Background recording was carried out for 20 min before the load of water-drinking samples. Then, a load water-drinking test was given in the form of 350 ml of warm water (temperature about 36 ° C) and the signal from the leads was recorded again for 20 minutes.

Description of drawings

The invention is illustrated by drawings.

Figure 1, which shows a diagram of the experimental implementation of the proposed method, the numbers indicate:

1 - subject;

2, 3, 4 - electrodes of an electrocardiogram (ECG);

5, 6, 7 — electrodes in the MP region;

8 - electroencephalograph;

9 - PC.

Figure 2 shows the dependence of the average amplitude on time for frequencies of 0.7 Hz; 1.5 Hz; 1.7 Hz, the time T in minutes is plotted on the abscissa axis, the amplitude A in μV is plotted on the ordinate axis, the numbers indicate:

10 - load, average;

11 - background, average;

12 - polynomial approximation of the average values obtained after the functional load;

13 - polynomial approximation of the average values obtained in the background recording.

FIG. 3 - represents the dependence of standard deviations on time for background recording and after a functional test, the time T in minutes is plotted on the abscissa axis, the standard deviation X in μV on the ordinate axis, the numbers denote:

14 - standard deviation values for the background;

15 - values of the standard deviation after the functional load.

The implementation of the method

In the course of the study, the bioelectrical activity of the bladder is recorded in a non-invasive way using an electroencephalograph 8, for example, a 21-channel Neurosoft Spectro-4 computer electroencephalograph from Neurosoft connected to a computer with MS Excel and Mathcad 14 software packages, an electroencephalograph connection diagram 8 to the subject is shown in FIG. 1. It should be noted that instead of an electroencephalograph, any other biopotential amplifier can be used, and an electroencephalograph was chosen due to its high sensitivity.

During the study, test subject 1 is placed in a comfortable position on a chair.

Three electrodes 5, 6, 7 are applied, made in the form of suction cups (http://www.medrk.ru/shop/index.php?id_group=78&id_subgroup=182&id_goods=20561), on the skin of the test person in the area of the bladder (MP). The electrodes are arranged along a horizontal line, and the electrode 5 located in the center is indifferent, it is a reference electrode for measuring the potential difference. The extreme electrodes 6, 7, together with the indifferent one, form two leads for registering the microwaves (biopotentials) of the bladder.

The connection to the electroencephalograph 8 is as follows: the indifferent electrode 5 is connected to the ear electrode socket (for example, A2 for Neuron-Spectrum-4), and the remaining 6, 7 are connected to the jacks corresponding to the same hemisphere as the ear electrode (for example , F8 and T4 for Neuron-Spectrum-4).

Put three clothespins electrodes 2, 3, 4, made in the form of clamps (http://www.medrk.ru/shop/index.php?id_group=78&id_subgroup=182&id_goods=17382), on the wrists of both hands and the ankle of the right leg. The electrode on the right foot 4 is used as grounding for the stability of the ECG signal, the electrodes on the wrists 2, 3 are designed to measure the potential difference, they form, in fact, the ECG signal of the first standard lead.

Connection to the electroencephalograph 8 is carried out as follows: the foot electrode 4 is connected to the grounding socket of the electroencephalograph, electrode 3 is connected to the ear electrode socket (for example, A1 for Neuron-Spectrum-4), and electrode 2 to any of the sockets corresponding to the hemisphere of that socket the ear electrode, to which the electrode 3 was connected. Thus, we find that the electrodes for recording the MP biopotential are connected to the electroencephalograph sockets corresponding to the right hemisphere of the brain, and the electrodes for registering ation ECG - to the left. There are also options for connecting electrodes from the MP to the left, and the ECG to the right, or both the MP electrodes and the ECG electrodes are connected to the same hemisphere.

Bladder signals are recorded between the 6 and 5, 7 and 5 electrodes by signals of the waves (biopotentials) of the bladder.

An ECG signal is recorded of the first standard electrocardiographic lead (between the left (3) and right hands (2), grounding on the right foot (4)). A lead is a certain position of two recording electrodes between which the difference in biopotentials is measured.

Background recording of signals is carried out for 20 minutes The obtained ECG and MP biopotential signals are subjected to mathematical processing using PC 5, which includes partitioning into files including data for one minute, normalization (bringing to a state from 0 to 1) using MS Excel software, and plotting the spectra of sections using the Fourier method for every minute in the environment of the mathematical package Mathcad 14. The spectra of signals from assignments from MP 6 and 5, 7 and 5 were filtered from the ECG signal (divide the spectrum of the MP assignment to the ECG assignment spectrum) in MS Excel. The most characteristic harmonics from the low-frequency region of the spectrum (0.5–2 Hz) are distinguished. For this purpose, frequencies of 0.7, 1.5, and 1.7 Hz were chosen, in which the amplitude most clearly changed from spectrum to spectrum. Then, the time dependences of the amplitudes of the most characteristic harmonics of the filtered spectra are plotted.

Then, a load water-drinking test is carried out in the form of 350 ml of warm water (temperature is about 36 ° C) and the signals from the MP and ECG from the leads are recorded again for 20 minutes. Similarly, the time dependences of the amplitudes of the most characteristic harmonics of the filtered spectra after a load test are built.

At the next stage of signal processing, the behavior of the selected harmonics is compared before and after a load of water-drinking samples. The results of such processing are presented in figure 2, which shows the dependence of the average amplitude on time for frequencies of 0.7 Hz; 1.5 Hz; 1.7 Hz, and FIG. 3, which shows the dependence of standard deviations on time for background recording and after a functional test.

As a result, we obtain the dynamics of changes in the most characteristic harmonics from the spectrum of the MP signal, which can be used to judge the degree of occupancy of the MP.

The theoretical basis of the method

This method is non-invasive and completely painless; it registers biopotentials from the skin surface in the area where the MP is located.

In the process of constructing the spectra of signals from the leads, it was revealed that the greatest activity is observed in the low-frequency range from 0 to 2 Hz. According to the analysis of the background spectra for the same time (at rest and under load), it was found that the correlation coefficient is slightly more than 0.8, that is, there is some degree of linear dependence between these spectra, therefore, they are similar. Therefore, three frequencies were selected in the range of 0.5–2 Hz, in which the dynamics of the amplitude change in time was most clearly traced. A correlation analysis was also performed for them (using the STATISTICA 10 program) in comparison with the background load. As a result, a correlation coefficient of ≈0.2 was established for each frequency. Therefore, these frequencies can be used to compare and analyze the bioelectric activity of the bladder. Moreover, harmonics with the highest amplitude (0.7 Hz, 1.5 Hz, 1.7 Hz) are characterized by a similar nature of the increase or decrease in amplitude in time, as well as its change with a frequency of 4-6 minutes.

From FIG. 2, which shows the dependence of the average values of the amplitudes of the selected three frequencies on time, you can see an increase in activity at frequencies of 0.7 Hz, 1.5 Hz, 1.7 Hz from the 10th minute after the load test (data were confirmed for 5 subjects) . From FIG. 3, we can draw a general conclusion about how the variance of the average harmonics (the amplitude of the biopotentials of the walls of the bladder) varied over time: for some time values, the variance is different between the functional load and background recording> 30%. The reliability of the obtained data exceeds 95% (significance level p = 0.03). It was calculated by the student method in the STATISTICA 10 program.

From the obtained results it follows that in the spectrum of biopotentials of the walls of the MP - in the case of a functional water-drinking sample, an increase in the activity of the biopotentials of the walls of the MP after the tenth minute of registration is observed. Note that this conclusion was obtained under these research conditions (the volume of water is its temperature). It is known that the time of water absorption in the human body depends not only on the chemical composition of the water and the psycho-functional state of the body, but also on the water temperature (Goremykin V.I., Usanov D.A., Prosova E.E. et al. Device for correction disorders of the urodynamics of the upper urinary tract in children with chronic pyelonephritis // Medical Technology, 2014, No. 4, P. 1-4).

It can also be noted that at the functional load (water-drinking sample), the dynamics of the selected harmonics changes: in the background recording, the harmonics behave almost the same in time, and after the drinking sample, a larger change in the amplitudes of the harmonics is observed over time, and periodically with an interval of about 12 min (Fig. 2). One of the main results of this method is the detection of several frequencies from the interval 0.5-2 Hz (0.7 Hz, 1.5 Hz, 1.7 Hz), on which you can see the dynamics of the walls of the MP, confirmed in a series of cases with sufficient reliability arising from the correlation analysis of harmonic data.

Thus, using the proposed method, a general pattern was revealed in the change in the bioelectrical activity of MP, which can be the basis for the diagnosis of the degree of MP filling and contractility of MP.

Application examples

Studies have been conducted on the dependence of the biopotentials of the MP wall on the degree of its fullness in several patients. MP biopotentials were recorded and filtered spectra of these signals were constructed before and after a load of water-drinking samples. After a water-drinking test, a general dynamics was revealed in the change in the activity of certain frequencies of 0.7 Hz, 1.5 Hz, 1.7 Hz from the range of the highest activity in the signal spectrum. Deviations from the average amplitudes of these harmonics increased over time, which coincided with the feeling of filling the MP in the subjects. These frequencies showed a general pattern both in several experiments with one subject and in the results obtained in the study of other subjects. The results of the application of this method showed the possibility of determining the degree of occupation of the MP by increasing amplitudes of the harmonics of the spectrum of the signal with EEG. The reliability of the data at the selected frequencies is more than 95% (significance level p = 0.03).

Claims (1)

A method for determining the fullness of the bladder by measuring with three electrodes, characterized in that the electrodes are applied to the skin in the area of the bladder and connected to a biopotential amplifier to obtain two leads, which measure the signals of the bioelectric activity of the walls of the bladder, and simultaneously record the electrocardiogram to filter the signal, mathematically process the received signals by normalizing and plotting the signal spectra of the bladder and ctrocardiograms by the Fourier method, filter the bladder signal from the electrocardiogram signal by dividing the spectrum of the bladder signal by the spectrum of the electrocardiogram signal, distinguish the characteristic frequencies of the spectra from the highest activity range of 0.7 Hz, 1.5 Hz, 1.7 Hz, these measurements are performed twice - before and after water-drinking load, the amplitudes of the characteristic frequencies are compared and the degree of fullness of the bladder is judged by their increase.

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