RU185119U1 - DEVICE FOR NON-INVASIVE DETERMINATION OF HUMAN ARTERIAL PRESSURE PARAMETERS - Google Patents

Abstract

The utility model relates to devices for continuous monitoring of physiological processes in the human body, namely, portable devices for non-invasively determining the parameters of a person’s blood pressure based on the simultaneous evaluation of pulse wave propagation data and data of electrocardiographic signals.

The technical result consists in ensuring the selectivity of recalibrating the device from external cuff type calibration tonometers when fulfilling the requirement to automatically determine the conditions for the need or desirability of recalibration during continuous operation of the device.

The device for non-invasive determination of blood pressure parameters, contains electrocardiographic signal sensors, a pulse wave signal sensor, a pulse wave parameter determination module by means of a functional dependence, a calibration module associated with a pulse wave parameter determination module, a control-analytical and control unit is introduced, while a calibration module and the control and analytical and control unit are interconnected via the first bidirectional data exchange channel E, the calibration module can exchange data with an external calibration sleeve type tonometer via a second bidirectional data communication channel, and the functional dependence of the blood pressure in the parameter estimation module is expressed as:

SBP = C ₀₁ + PAT * C ₁₁ + HR * C ₂₁ ;

DBP = C ₀₂ + PAT * C ₁₂ + HR * C ₂₂ , where

SBP-systolic pressure, DBP-diastolic pressure, PAT-time of pulse wave arrival, HR - heart rate, С ₀₁ С ₀₂ С ₁₁ , С ₁₂ , С ₂₁ , С ₂₂ - coefficients, individual for each individual patient, determined and adjusted according to the results of calibration (recalibration). 3 ill.

Description

The utility model relates to devices for continuous monitoring of physiological processes in the human body, namely, portable devices for non-invasively determining the parameters of a person’s blood pressure based on the simultaneous assessment of pulse wave propagation data and data of electrocardiographic signals, and can be used as a device for diagnostics the state of the human body, and as part of instruments and complexes for diagnostic purposes.

A device based on integrated-type microcircuits is known for detecting and evaluating parameters of a person’s blood pressure in a continuous mode, as described in WO 2018/006501 A1 IPC A61B 5/0205, A61B 5/0402 publ. 01/11/2018, containing a photoelectric detection unit with a light source and a photodetector (based on diodes), a photoplethysmographic signal generating unit with its corresponding analog-to-digital converter, an electrocardiographic signal generating unit with its corresponding analog-to-digital converter, a data processor and an interface unit ( based on an interface like I2C) for transmitting data from a data processor. In a device of this type, one microcontroller is enough to control a set of modules (including those responsible for converting and processing signals from heterogeneous sensors), and both simultaneous operation of several modules connected to one I2C bus and stable operation when connecting and disconnecting are provided additional modules during the operation of the device. Also known is a wearable device described in the application US 2017/0055845 A1 IPC A61B 5/0205, A61B 5/00, A61B 5/04, publ. 03/02/2017, installed on the wrist or in another place on the body of a person (user), designed to perform various applications by providing information and / or access services and containing a light source, photodetector, electrocardiographic signal sensor, amplifier, multiplexer, analog-to-digital converter and a controller for controlling the main units of the device and extracting two samples of data digitized by an analog-to-digital converter for certain periods of time - multiplexed with signals from the output of the photodetector and multiplexed signals from the output of the sensor of electrocardiographic signals, in which one analog-to-digital converter is used to extract each of two or more (if necessary) samples, and the selection occurs in such a way that the time dependence between the detected signals (for example, relative synchronization between samples of detected variables) can be controlled (regulated) or known. These devices do not have the ability to calibrate data during operation, which reduces the reliability of the assessment of blood pressure parameters.

In the patent RU 2509529 C2 IPC A61B 5/0285, publ. 09/27/2012, Bull. No. 27 describes a method for monitoring a patient’s blood pressure and a system for monitoring a patient’s blood pressure based on a method comprising a pulse wave propagation velocity unit configured to determine a pulse arrival time signal from a patient based on a known pulse wave propagation velocity measurement technique, and also comprising an accelerometer and a control device configured to normalize the pulse arrival time signal for the patient position and triggering additionally receiving operation or a blood pressure value taking into account the pulse arrival time signal and the DC component of the accelerometer signal. From the description of the patent it follows that in one of the most preferred variants of the system, the pulse wave propagation velocity block comprises a sensor for recording electrocardiographic signals and a pulse sensor, preferably an optical sensor, configured to register a plethysmographic signal from a patient. In practice, this means that the operability of such a system is limited to cases where the control device is configured to turn on the signal if the blood pressure when measuring blood pressure by a cuff method exceeds a predetermined threshold value for blood pressure, or if the normalized signal of the pulse arrival time is lower or higher than a predefined threshold value of the pulse arrival time, and at the same time, the launch of an additional ope ation or receipt of blood pressure values is dependent on the position change person. The implementation of such a system implies that the use (wearing) of the cuff by the patient will be constant, in addition, the moment of forced start of automatic recalibration is unexpected for the patient, which can lead to stress and increase, as a result, blood pressure, which can reduce the reliability of measurements.

The closest in technical essence is the device described in the patent for invention US 7374542 B2 IPC A61B 5/02, A61B 5/04, publ. 05/20/2008 and containing an electrocardiographic signal sensor for recording the measured signal of the electric heart potential, a pulse sensor for recording the measured pulse pressure wave signal, an evaluation module for determining the propagation time of the pulse pressure wave by means of a functional relationship containing the first part reflecting the elastic response of the vessels in active mode, and containing the second part, reflecting the elastic response of the vessels in the passive mode. From the description of the patent for the invention it follows that the evaluation module includes a calibration module designed for additional calibration based on data obtained from calibration measurements and used further in a functional relationship. However, in this device, calibration is carried out only before it starts to work and is possible only in manual mode, the device does not have the ability to automatically calibrate during continuous operation, operator errors may occur during manual data entry or when data is received and entered late.

The technical result consists in ensuring the selectivity of recalibrating the device from external cuff type calibration tonometers when fulfilling the requirement to automatically determine the conditions for the need or desirability of recalibration during continuous operation of the device. The technical result is achieved due to the fact that in the device for non-invasive determination of blood pressure parameters containing electrocardiographic signal sensors, a pulse wave signal sensor, a pulse wave parameter determination module by means of a functional dependence, a calibration module connected to the pulse wave parameter determination module is introduced analytical and control unit, while the calibration module and the control-analytical and control unit are interconnected first means for bidirectional data exchange, the calibration module can exchange data with an external calibration sleeve type tonometer via a second bidirectional data communication channel, and the functional dependence of the blood pressure in the parameter estimation module is expressed as:

SBP = C ₀₁ + PAT * C ₁₁ + HR * C ₂₁ ;

DBP = C ₀₂ + PAT * C ₁₂ + HR * C ₂₂ , where

SBP - systolic pressure, DBP - diastolic pressure, PAT - time of arrival of a pulse wave, HR - heart rate, С ₀₁ С ₀₂ , С ₁₁ , С ₁₂ , С ₂₁ , С ₂₂ - coefficients, individual for each individual patient, determined and corrected taking into account the results of calibration (recalibration).

The utility model is illustrated by the figures:

FIG. 1 - Image of the connection diagram of the device to the patient;

FIG. 2 - Image of a general block diagram of a device;

FIG. 3 - Image of a block diagram of the algorithm of the device with an individual patient;

A device for non-invasively determining a person’s blood pressure parameters is shown in FIG. 1 (the connection diagram for the patient and the location of the sensors is shown) and in FIG. 2 (general block diagram of the device). The following notation is introduced:

1 - patient;

2 - sensors of electrocardiographic signals;

3 - motion sensor (position);

4 - cuff;

5 - the main unit;

6 - pulse wave sensor;

7 - calibration cuff tonometer;

8 - electrocardiographic module;

9 - module for determining the time of arrival of the pulse wave;

10 - module determining the parameters of the pulse wave;

11 - module for assessing blood pressure parameters;

12 - control and analytical and control unit;

13 - display;

14 - alert unit;

15 - the first bidirectional data exchange channel;

16 - second bi-directional data exchange channel;

17 - calibration module;

18 - module parameters of motor activity;

In FIG. 3 shows a block diagram of the algorithm of the device with a single patient.

Before starting the operation of the device, on an individual prepared patient 1, electrocardiographic signal sensors 2 are installed, a pulse wave sensor 6 and a motion (position) sensor 3, the main unit 5, and also a cuff 4.

At the beginning of the work, the threshold values SBP _min , SBP _max , DBP _min , DBP _max , ΔРАТ are set, where SBP _min , SBP _max is the minimum allowable and maximum allowable threshold value of systolic pressure SBP, DBP _min , DBP _max is the minimum allowable and maximum allowable the threshold value of the diastolic pressure DBP, ΔРАТ - the permissible range of variation of the pulse wave arrival time PAT (in percent) and transmission to the module for assessing blood pressure parameters 11 with subsequent transfer to the control and analytical and control unit 12 according to the first bidirectional communication channel 15.

The device is initially calibrated using the cuff 4 of the cuff type 7 calibration tonometer (after the initial calibration, the cuff can be left or removed as necessary), the calibrated blood pressure parameters are transferred from the cuff type 7 calibration tonometer to the calibration module 17 via the second bi-directional data exchange channel 16.

The setting value of the arrival time of the pulse wave PAT _{0 is} determined. The primary determination of the coefficients С ₀₁ С ₀₂ , С ₁₁ , С ₁₂ , С ₂₁ , С _{22 takes place} — the coefficients that are individual for each individual patient, determined and adjusted taking into account the results of calibration (recalibration) in the control and analytical and control unit 12 and their delivery to the module for estimating blood pressure parameters 11 via the first bi-directional data exchange channel 15. Hereinafter, calibration is understood as the initial calibration of the device using cuff 4 of a cuff type calibration tonometer 7 after starting bots of the device with an individual prepared patient 1, and recalibration means any recalibration of the same device when working with the same individual patient prepared patient 1, which is necessary or desirable during the operation of the device to implement and complete the procedure for assessing blood pressure parameters .

The determination of the coefficients C ₀₁ , C ₀₂ , C ₁₁ , C ₁₂ , C ₂₁ , C ₂₂ can be implemented on the basis of well-known digital signal processing algorithms, in particular, in the publication Cattivelli FC, Garudadri N. Noninvasive Cuffless Estimation of Blood Pressure from Pulse Arrival Time and Heart Rate with Adaptive Calibration // Proc. 2009 Sixth International Workshop on Wearable and Implantable Body Sensor Networks, pp. 114-119, doi 10.1109 / BSN.2009.35 describes an algorithm for obtaining these coefficients during initial calibration and their corrections during subsequent recalibrations based on the least squares method when used in the method of estimating blood pressure, modern hardware and software makes it possible to select any type digital signal processing algorithms for each individual patient, depending on the measurement methodology and working conditions, this is determined in the instrument settings before working with each individual patient.

After the start of continuous operation, the signal of the electric potential from the heart muscle is recorded by the electrocardiographic signal sensors 2 and from the outputs of the electrocardiographic signal sensors 2 is transmitted to the inputs of the electrocardiographic module 8, the pulse pressure wave signal is recorded by the pulse wave sensor 6 and transmitted from the output of the pulse wave sensor 6 to the input module for determining the parameters of the pulse wave 10, the signal from the motion sensor (position) 3 is transmitted to the input of the module of parameters of the motor ac 18. From the outputs of the electrocardiographic module 8 and the pulse wave parameter determination module 10, the signals are transmitted to the pulse wave arrival time determination module 9. In this case, the heart rate HR data are simultaneously transmitted from the electrocardiographic module 8 to the control and analytical and control unit 12 and in the module for evaluating the parameters of blood pressure 11, from the module for determining the time of arrival of the pulse wave 9, data on the time of arrival of the pulse wave PAT are also output simultaneously to the control analytical and control unit 12 and to the module for assessing blood pressure parameters 11, and from the module of parameters of motor activity 18, the signals are transmitted to the control and analytical and control unit 12. In the module for assessing blood pressure parameters 11, the estimated values of arterial systolic and diastolic pressure are calculated in accordance with with functional dependence:

SBP = C ₀₁ + PAT * C ₁₁ + HR * C ₂₁ ;

DBP = C ₀₂ + PAT * C ₁₂ + HR * C ₂₂ .

Since the module for evaluating the parameters of blood pressure 11 and the control-analytical and control unit 12 are interconnected via the first bidirectional data exchange channel 15 and the data are exchanged continuously, the calculated estimated values are sent to the control-analytical and control unit 12 in a continuous mode and, when necessary, they are visualized on display 13.

In the process, in the control-analytical and control unit 12, the calculated values of the systolic pressure SBP and diastolic pressure DBP are checked for falling within the acceptable threshold values (first level check). In case of failure to check the first level, an alarm (sound, light, etc.) is issued in the notification unit 14 and messages about the need for recalibration either on the display 13 or in the notification unit 14, or in some other way, if accepted the patient makes decisions about recalibration by putting on cuff 4 of a calibration type 7 cuff tonometer, calibration data is transferred from a calibration type 7 cuff tonometer to the device via the second bi-directional data exchange channel 16 (it can be l wireless).

In the case of successful completion of the first level check during operation in the control-analytical and control unit 12, the calculated values of the arrival time of the pulse wave PAT are checked for falling into the allowable range of values of the arrival time of the pulse wave PAT (in percent) through the module of the ratio of the value of PAT to value of PAT ₀ (second level check). In case of failure to check the second level, an analysis of the previous motor activity occurs and, depending on the results, either an alarm (sound, light, etc.) is issued in the notification unit 14 and the messages about the desirability of recalibration either on the display 13 or in the unit notifications 14, or in some other way, and if a decision is made to recalibrate, the patient carries it out, putting on a cuff type 7 tonometer for this purpose, or an analysis of the development trends of the situation with subsequent transfer anovkoy PAT values ₀ and continued operation.

In the case of successful completion of the second-level verification during operation, the control-analytical and control unit 12 checks the data for physiological reliability (third-level verification). If the data are physiologically unreliable, then an alarm (sound, light, etc.) is issued in the notification unit 14 and messages about the need to check the status of the sensors. In the case of successful completion of all checks, the cycle of assessing blood pressure parameters is repeated.

Claims (4)

A device for non-invasive determination of blood pressure parameters, containing electrocardiographic signal sensors, a pulse wave signal sensor, a pulse wave parameter determination module by means of a functional relationship, a calibration module associated with a pulse wave parameter determination module, characterized in that a control and analytical and a control unit, while the calibration module and the control-analytical and control unit are interconnected by means of of the first bidirectional data exchange channel, the calibration module has the ability to exchange data with an external cuff type calibration tonometer through a second bi-directional data exchange channel, and the functional dependence in the module for assessing blood pressure parameters is expressed as:

Where SBP - systolic pressure, DBP - diastolic pressure, PAT - time of arrival of a pulse wave, HR - heart rate, C ₀₁ , C ₀₂ , C ₁₁ , C ₁₂ , C ₂₁ , C ₂₂ - coefficients, individual for each individual patient, defined and corrected taking into account the results of calibration (recalibration).

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