RU2629036C1 - Method for arterial pressure measurement - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: pulse wave sensors are fixed on the wrists of both hands, and the data from the pulse wave sensors are processed synchronously, determining the delay between heartbeats. Then, the delay variation is monitored over time, which is taken corresponding to the systolic pressure change.

EFFECT: method allows for a possibility of continuous monitoring of changes in blood pressure.

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Description

The invention relates to medicine, namely cardiology, and can be used for non-invasive continuous monitoring of changes in blood pressure.

Existing methods for measuring blood pressure are divided into two groups: methods of direct (invasive) and indirect (non-invasive) measurements. Non-invasive methods are based on the processing and analysis of various indicators indirectly associated with hemodynamics and blood pressure. The most common of these are oscillometric and auscultatory methods. The disadvantages of these methods include the need to inflate the cuff for occlusion of blood vessels and the ability to perform periodic measurements only at certain points in time, whereas in many cases it is necessary to continuously and sufficiently continuously monitor blood pressure indicators. The work of Shulgin and coauthors “Measurement of blood pressure based on the joint processing of a set of physiological parameters” (Klin, informat. And telemed. 2012. V. 8. Issue 9. P. 38-44) shows the relationship between such hemodynamic parameters as elasticity the walls of the blood vessel (artery) and the propagation time of the pulse wave. A study was conducted of a certain number of subjects who recorded the value of the phase shift (Δτ) between two photoplethysmograms, obtained synchronously from sensors located on the left and right hands. According to the results of this study, it is assumed that the Δτ value obtained by the indicated measurement method is more affected by the elasticity of the blood vessel walls than the pulse wave propagation time, so Δτ can serve as an indirect sign of a change in blood pressure.

A known method of measuring blood pressure using pulse wave analysis, including illumination of a blood-bearing tissue, converting the light flux into an electrical signal and processing the received light wave, has several photosensitive transducers with photosensitive regions oriented to identify local pulsation zones on the blood-bearing tissue (RF Patent No. 2199943 according to class A61B 5/02 of 03/10/2003).

The disadvantage of this method is the limited functionality of the method, and the main emphasis on the use of this method is given to ensure stable recording of the pulse. Measurement of blood pressure using this method is very problematic due to the complexity of the operation of orientation of the photosensitive regions, which ultimately leads to a complication of the process of measuring blood pressure and a decrease in the accuracy of measurement.

There is also a method of measuring blood pressure using pulse wave analysis, namely, blood pressure is determined by the propagation velocity of the pulse wave of a large circle of blood circulation (RF patent No. 2118122 according to class A61B 5/0245 of 08/27/1998).

Systolic pressure according to the method specified in this patent was determined by the difference in the initial phases of the compared pulse sequences and the phase of the trailing edge of the second pulse sequence, and diastolic pressure - by the phase difference of the leading edge of the first pulse sequence and the phase of the trailing edge of the second pulse sequence.

The disadvantage of this method is the relatively low accuracy of pressure measurement, because when using it, a fixed connection of sensors to various places on the patient’s body is required for a stable undistorted pulse wave form. The objective of the invention is to develop a new methodology for determining changes in blood pressure based on the analysis of changes in Δτ between two photoplethysmograms obtained from the left and right hands of the subject.

The technical result of the invention is the ability to continuously monitor changes in blood pressure.

The specified technical result is achieved by the fact that the claimed method of measuring blood pressure, comprising converting the light transmission of a specific area of tissue depending on its blood supply into an electrical signal, analysis of the electrical signal in the recording and processing unit, followed by determining changes in blood pressure, characterized in that during the measurement pulse wave sensors are fixed on the wrists of both hands, and data from the pulse wave sensors are processed synchronously, determining the delay between the pulse signals, then the change in the delay is monitored over time, which is taken to correspond to the change in systolic pressure, or the difference in systolic and diastolic pressures.

Brief Description of the Drawings

In FIG. 1 shows a data flow direction diagram;

In FIG. 2 is a diagram illustrating an example of receiving a delay.

The method is as follows. The first pulse wave sensor (1) is fixed on the left wrist of the subject. A second pulse wave sensor (2) is located on the right wrist of the subject.

Pulse signals from the patient through transceivers (3, 4) are fed to the input of the signal recording and processing unit (6), based on a microcontroller (5). This block (6), based on the calculation of the Δτ value averaged over a certain interval between the signals from the left and right hands, containing information about the amplitude of the pulse wave, in accordance with the established algorithm, provides information about the change in Δτ, which is an indirect sign of a change in systolic pressure or differences in systolic and diastolic pressures. For unambiguous measurements for each subject, Δτ is calculated relative to the signal received from the left wrist. The measurement of signals carrying information about the change in the amplitude of the pulse wave is synchronous, in other words, the signals from the left and right hands are processed, received at the same time (Fig. 2). The need for synchronous measurements is due to the fact that the instantaneous values of Δτ can vary, i.e. the shape of the curve of the pulse wave will be uneven, and it is practically impossible to select Δτ with the required accuracy of ± 1 ms.

Comparison of the claimed technical solution with the prototype made it possible to establish its compliance with the criterion of "novelty." In the study of other well-known technical solutions in the art, signs that distinguish the claimed solution from the known, were not identified and therefore they provide the claimed invention with the criterion of "significant differences".

Claims (1)

A method for measuring blood pressure, including converting the light transmission of a specific tissue site depending on its blood supply into an electrical signal, analyzing an electrical signal in a recording and processing unit, and then determining a change in blood pressure, characterized in that during the measurement, pulse wave sensors are fixed on the wrists of both hands and the data from the pulse wave sensors is processed synchronously, determining the delay between the pulse signals, then the delay change is monitored over time, which is taken corresponding to a change in systolic pressure.

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