RU27427U1 - DEVICE FOR MONITORING DIALYSIS LIQUID DURING DIALYSIS - Google Patents

Description

Device for dialysis fluid monitoring in dialysis process

The invention relates to the field of technical physics, namely to the study and analysis of materials using optical media and can be used for continuous monitoring of the composition of the dialysis fluid during dialysis.

A known hemodialysis monitoring system for a hemodialysis machine (US No. 5666806, GO1N 21/31, 09/02/1997). It includes a module for sampling a liquid, a module for determining the concentration of urea, which is based on an ion-selective electrode, an analytical module. The monitoring method includes: conducting a test to determine the concentration of urea in the blood before hemodialysis, based on indicators of the urea concentration in the dialysate (the process of obtaining balanced dialysis samples), periodic sampling of the dialysate for analysis with determining the actual dialysate perfusion rate, determining the urea concentration in the collected sample, transfer data to the analytical module, calculation of hemodialysis adequacy parameters using a two-pool model of urea distribution in the body, forecaster these parameters at the end of hemodialysis, correction of hemodialysis regimes. As a result of monitoring, the data obtained can be used to predict the final parameters of purification, and if they are insufficient or excessive, change the hemodialysis regimen.

The disadvantages of such a system include a complex calibration system for the measuring module, periodic electrode replacements, a wide range of calibration reagents are necessary, only one urea can be determined, the process of obtaining balanced dialysate samples is performed with the participation of the operator. v A device for monitoring a liquid biological medium (RU 216179) GO1N 21/31, 12/30/1998). The device contains installed

sequentially a light source, an optical system for generating a light beam, a cuvette with a biological liquid medium flowing through it, a spectrometer, a controller. The device further comprises a computing control unit, a control unit for recording and tuning parameters of the spectrometer, a unit for processing the current spectrum value, a control unit for monitoring parameters, a timer, an input data unit, a data processing unit, an output data unit, a display, an algorithm unit, and a computing control unit connected to

G 01 N21 / 31, A 61 M1 / 14

on the one hand, with the controller, and on the other hand, with the control unit for recording and tuning parameters of the spectrometer and an input data unit, which, in turn, is connected to the control unit for monitoring parameters, while the first output of the computing control unit is connected to the input of the processing unit of the current spectrum, the output of which is connected to the display, and the second output of the computing control unit is connected to serially connected timer, processing unit and block of algorithms, which is connected to the display and unit m output data, the output processing unit is connected to the current range of the input timer.

The disadvantages of such a monitoring system include the impossibility of determining the concentration of individual components of the sample, since this requires an additional analysis technique.

The tasks that are solved by the invention are to increase the reliability of the information, expand the number of controlled indicators of the flowing dialysis fluid, the operation of the system in continuous on-line mode. The tasks are solved as follows.

The dialysis monitoring device during dialysis contains a light source installed on a regular basis, an onrvwea beam-forming system, a flow cell with the tested fluid flowing through it, a spectrometer, a controller, a computer control unit, a retsfection and spectrometer settings control unit, a current spectrometer processing unit, a current specf processing unit, a control unit monitoring parameters, timer, input block, display, block of algorithms. The device is characterized in that it further comprises a dilution control unit, a sampling unit, a solvent intake unit, a dilution unit, and a dispenser, while the dilution degree control unit is connected on one side to the subtraction control unit, and on the other hand to the dilution unit, which in turn, connected to the sampling unit, the solvent intake unit and a dispenser, the outlet of which is connected to the cell. The invention is illustrated by drawings: in FIG. 1 shows the functional axis of the device; in FIG. 2 - spectrograms of the dynamics of changes in the transmission spectra of the native dialysis fluid during a peritonial dialysis session; in FIG. 3 spectrofamms of the same session with controlled dilution (in this case, 1: 3).

spectrometer settings 7, current spec processing unit 8, display 9, monitoring parameter control unit 10, timer 11, input data unit 12, data processing unit 13, output data unit 14, algorithm block 15, sample collection unit 16, solvent intake unit 17 , a liquid dilution unit 18, a dispenser 19, a control unit for the degree of dilution zhstskost / 20.

The device operates as follows. The radiation of the continuous spectra source 1 by the optical system 2 is directed to the selected zone of the cell 3 with the studied dialysis fluid and the radiation transmitted through the cell is focused on the exit slit of the multichannel spectrometer 4. The multichannel specimeter is a polychromator with an inward diffraction grating located on the Rouletz fugue. The grating focuses the spectral distribution of the radiation flux on a line of photodetectors. The speyrape region, within which the radiation decomposes into a spectrum, is determined by the lattice parameters (the number of strokes per unit dpi, the angle of the stroke profile, etc.). The number of elements in the line of photodetectors corresponds to the number of retractable spectral components (the number of retransmitted channels). The width of an individual element of the ruler is proportional to the portion of the spectra averaged during a separate measurement. The correspondence of the channel number to the wavelength is determined by spectral calibration of the spectrometer. The electrical signals from the output of each element of the line of photodetectors are converted into a digital code and read by the controller 5 into the main memory of the computer 6. The operation mode of the spectrophotometer is carried out according to computer commands. Before monitoring, a liquid enters the cuvette that does not contain substances controlled during the monitoring process and is a reference standard (distilled water, dialysate, solvent, etc.). Using the control unit 7 set the operating mode of the spectrometer and measure the spectra of 100% sital and specimen dark current photodetectors. In the processing unit of the current spec 8, the spectral transmittance of the radiation transmitted through the cell at a given time is calculated. The minimum reading time for the entire spectrum is determined by the inertia of the photodetectors, the accumulation time (duration of exposure of the spectrum on the photodetector line), and the number of samples during averaging. These parameters are set by the control unit 7. The calculated current transmission spectrum is displayed on the display screen 9.

The monitoring mode of the test fluid is set in block 10, which indicates the duration of the monitoring process, the frequency of control, dialysate flow rate, blood flow velocity and a threshold transmittance value that ensures febrile measurement reliability. Usually threshold value

spectral transmittance is 2 ... 5%. Then, the specular absorption characteristics of the dialysate-controlled components are introduced into the input data block 12, the spectra region within which the analysis will be carried out is established, the threshold value of the specular transmittance Tpor is entered, the sampling unit 16 is connected to the dialysis material output matstrapi, and the solvent intake block 17 to dialysate input line and turn on timer 11. From now on, the liquid transmission spectrum that is currently in the cell will be displayed on the display screen. For modern photodiode arrays, the minimum reading time of the speckf does not exceed a few milliseconds. Taking into account the exposure duration and the number of averaging samples, the reading time of one spectrum and calculation of the transmission spectrum is 1 ... 10 s. This value determines the frequency of change of the phafic display of speckf on the screen. By the control command of the timer 11 corresponding to the set interval of the monitoring mode, the dilution control unit 20 opens the valves connecting the sampling unit 16, the dilution unit 18, the dispenser 19 and the cuvette 3 and the dialysis fluid from the output map dial of the dialysate fills the cuvette, after which the current spec, located at the current moment of time in the RAM, it enters the processing unit 12. In this block, a matrix of values of the specific transmittance of the studied liquid is allocated, which corresponds to the setting hydrochloric spekfalnoy area and carried spekfa preliminary analysis of the measured values obtained by favneniya spekfalnyh transmittances T c Tpor set threshold value. If within the selected spectral region T Tpor., The glass enters the block of algorithms 13 to analyze the composition and calculate the concentration of components in the sample with a record in the output block 14, after which monitoring continues until the next measurement. If in some section of the spec T Tpor., Then, at the signal of the control unit of dilution degree 20, a valve will open that connects the solvent intake unit 17 and dilution unit 18, and pure dialysate in the volume equal to the volume of the dialysis fluid will enter the dilution unit, after which diluted dialysis fluid (1: 1 dilution) through the dispenser will enter the cuvette. If the analysis of specf diluted in a 1: 1 dialysis fluid shows that the condition T Tpor is not met, the dilution process continues according to the same scheme (1: 2.1: 3, etc.). When the condition Т Тпор is fulfilled in the entire embedded spectral region, the current spectrum of the dialysed liquid diluted in a certain proportion is sent for analysis to the block of algorithms 15, and information on the dilution degree of the dialysis liquid, the spectral of which is measured, is entered into the output block 14.

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The calculation of the concentration of the controlled components is carried out according to an algorithm that implements the inventive method. When carrying out the calculation, informative spectral characteristics of the controlled components are used and the concentration values of these components corresponding to the minimum error are determined. Analysis of the calculation results is carried out according to the established threshold values in the following sequence: checking for the absence of controlled components in the liquid; sequential check for the presence of only one of the components; checking for a combination of components. The result of the analysis, taking into account the degree of dilution, is recorded in the output data block 14 and displayed on the display as a function of concentration versus time. After this, the device is returned to the processing mode of the current spectrum, which continues until the next control command of the timer, after which a new calculation cycle begins. At the end of the set monitoring time, a data bank is formed in the output data block, including the time and concentration values of each component during the entire monitoring session at set intervals.

Example. Monitoring the composition of dialysis dialysis (dialysate) peritonial dialysis session in order to determine the concentration and amount of uremic toxins removed during peritonial dialysis.

The inventive device was connected to the output line of the peritoneal catheter in the hemodialysis department of the City Center for Hemocorrection in St. Petersburg and the process of 35 sessions of peritoneal dialysis of patients receiving treatment for chronic renal failure (CRF 111 st.) Was monitored. The admissibility of the procedure for each patient was up to 34 hours. Dialysate samples were studied at the moments of dialysate composition change during the session:

1st stage - from 22 to 8 hours - sample 0;

Stage 2 - from 8 to 11 hours - sample 1;

Stage 3 - from 11 a.m. to 3 p.m. - sample 2;

Stage 4 - from 15 to 20 hours - sample 3;

5th stage - from 20 to 22 hours - sample 4;

6th stage - from 22 to 8 hours - sample 5.

The uremic toxins in the dialysate were monitored - creatinine, urea, uric acid, phosphates, as well as the total protein excreted from the patient's fove during the session. In parallel, laboratory control of a number of samples was carried out for the content of the above components in them by known biochemical methods.

For all the patients studied, the monitoring of the leurofamma of the native dialysis fluid showed that a high absorption level due to the high concentration of uremic toxins and metabolites contained in it makes it impossible to analyze the composition and the need for dosed dilution.

The view of the spectrograms of the dynamics of the transmission spectra of the native dialysis fluid during the peritonial dialysis session of one of the patients is presented in figure 2 (without dilution). In Fig. 3, spectrograms of the same session are presented using the proposed device (controlled dilution of the initial cells in a ratio of 1: 3) at a given value of Tpor 0.03.

During the monitoring of 35 sessions of peritoneal dialysis, a 1: 1 dilution was required for 2 patients, a 1: 2 dilution for 5 patients and a 1: 3 dilution for 30 patients.

The content of creatinine, urea, uric acid, phosphates and protein in the dialysis fluid was monitored. Table 1 presents the results of calculating the concentration of controlled components during the monitoring of one of the patients (patient G., session 13-14.02.01) according to the claimed method and the data of biochemical measurements.

Table 1. Monitoring data for the peritonial dialysis session (patient G., session 13-14.02.01)

/ r x // Note that timelines of the dynamics of concentration and excretion volume were displayed on the screen during the session and the doctor could monitor the progress of the treatment procedure.

The data obtained made it possible to estimate the amount of uremic toxins and metabolites excreted from the patient's body during the session. Comparison of the results of the verification check and the readings of the device showed that the relative measurement error does not exceed 10%. Note that the time graphs of the concentration dynamics and the amount of excretion were displayed on the ephane display during the hemodialysis session and the doctor could control the course of the treatment procedure. At the same time, the relative indicator of the effectiveness of the session was calculated - the ratio of the number of removed toxins per square meter of the patient's surface.

 A

Claims (1)

A device for monitoring dialysis fluid during dialysis, containing a sequentially installed light source, an optical system for beam formation, a flow cell with a test fluid flowing through it, a spectrometer, a controller, a computational control unit, a control unit for recording and tuning parameters of the spectrometer, a processing unit for the current spectrum, monitoring parameters control unit, timer, input data block, display, algorithm block, characterized in that it further comprises a control block a dilution unit, a sampling unit, a solvent intake unit, a dilution unit, and a dispenser, wherein the dilution degree control unit is connected on one side to the computing control unit and, on the other hand, to a dilution unit, which in turn is connected to the sample collection unit, a solvent intake unit and a dispenser, the outlet of which is connected to the cell.