RU2694737C1 - Apparatus for determining arterial pressure in the shoulder on each heart beat - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention refers to medical equipment, namely to devices for determining arterial pressure in the arm on each cardiac contraction. Device includes a Korotkoff tones block. Unit comprises a sound vibration sensor and a shoulder cuff, a pressure control unit, a unit for continuous non-invasive measurement of arterial pressure, a processing and control unit, an information display device. Processing and control unit is connected with a sound vibration sensor, with a pressure control unit, with a unit for continuous non-invasive measurement of arterial pressure, with an information display device. Sound vibration sensor is configured to record Korotkoff tones. Pressure control unit is connected with shoulder collar. Processing and control unit is configured to control the pressure control unit, obtain and process data from the sound vibration sensor and the unit for continuous non-invasive measurement of arterial pressure. Processing and control unit provides the continuously measured arterial pressure conversion so that the moments of time of intersection of the pulse waves anacrotic limb with the pressure curve in the shoulder cuff are maximally matched with the Korotkoff tones occurrence time moments, and determines values of systolic and diastolic arterial pressure on each cardiac contraction.

EFFECT: device provides higher accuracy of measuring arterial pressure by measuring arterial pressure on each heart rate cycle, which enables continuous monitoring of arterial pressure in patients with rhythm disturbance.

10 cl, 2 tbl, 10 dwg

Description

The invention relates to medical equipment, namely to the means of assessing blood pressure according to the results of continuous non-invasive blood pressure measurement on each cycle of heartbeat and periodic fixation of Korotkoff tones in the shoulder. The invention can be used for medical purposes to determine the parameters of blood pressure, especially for heart rhythm disorders.

A well-known method for measuring blood pressure (BP) Korotkov [1], which is currently the approved method for non-invasive blood pressure measurement [2], is widely known. The cuff is put on the shoulder of the patient. A stethoscope (microphone) is placed on a projection of the brachial artery in the ulnar fossa. A cuff pressure is created that exceeds the maximum BP, clamping the artery and stopping the blood flow. The cuff pressure is reduced at a constant speed (2-5 mm Hg / s). When the pressure drops to a level equal to the patient's systolic arterial pressure (MAP), at the time of exceeding a characteristic sound signal will appear - Korotkov tone. As long as the pressure in the cuff is at the level between the SBP and the diastolic blood pressure (DBP), Korotkov's tones will be heard, since the BP is sometimes higher, then lower than the pressure in the cuff at different moments of the cardiac cycle. When the pressure in the cuff approaches the DBP, the sound changes, becomes muffled and disappears completely, because cuff does not create any restrictions for blood flow.

However, this method allows to evaluate only one value of SAP and DAP during the measurement time, and the obtained values refer to different heartbeats. The error of the method is determined by the magnitude of the variations in GARDEN and DBP. This leads to the ambiguity of determining SAD in patients with pronounced “auscultatory failure” and does not allow determining blood pressure in patients with severe rhythm disturbance, since BP is significantly different in every heartbeat.

Another method of non-invasive blood pressure measurement is known - the unloaded artery method proposed by Penyaz [3]. This principle is based on a continuous assessment of the volume of finger vessels using a photoplethysmographic signal and a tracking electropneumatic system that creates pressure that counteracts the change in the diameter of the arterial vessels passing under the cuff in the finger. In this case, the constancy of the photoplethysmographic signal is ensured at a given level, and the pressure in the cuff repeats the pressure of the blood in the finger arteries. Also known are devices [3-8], whose functions include continuous non-invasive measurement of blood pressure in the blood vessels of the fingers, based on the unloaded artery method. When these devices operate, external pressure is created on one of the phalanges of the finger, and at the same time a photoplethysmogram is recorded on this area of the body. External pressure is created by the finger cuff, and the photoplethysmogram is recorded by means of optoelements embedded in the body of the cuff.

However, blood pressure is measured at the peripheral part of the artery. The absolute pressure values change when the measuring point is removed from the heart, therefore, the absolute pressure values in the finger differ from the pressure in the shoulder. As a rule, SBP increases, while DBP decreases, while maintaining relative pressure change.

The method of applanation tonometry is known [9]. In this case, the cuff is located on the wrist and contains a tonometer sensor located above the radial artery. The sensor presses the artery to the radial bone so as to sufficiently compress it, to make contact with its wall flat (but not squeeze before occlusion). Then through the vessel walls with the help of pressure sensors recorded pulse changes in blood pressure. The amount of pressure needed to flatten, but not close the artery, is known as the “pressing pressure” and is calculated using a fairly complex algorithm that includes preliminary estimates of the GARDEN, DBP and pulse pressure.

To measure blood pressure it can be used as an initial parameter, the velocity of propagation of a pulse wave, which is a function of blood pressure [10]. This method consists in the fact that the calculation of blood pressure in each heartbeat is based on the propagation time of the pulse wave, which is determined from the ECG and photoplethysmographic signal from a part of the patient's body.

It should be noted that conversion to non-invasive pressure, measured at the shoulder, is performed on most devices, although the calibration methods are different. In the device company CNSystems [11] measure blood pressure in the shoulder before measuring continuous blood pressure in the finger. The individual transfer function is then calculated and applied to the HELL signal in the finger. However, the measurement of blood pressure in the shoulder is divided in time with the measurement of blood pressure in the finger and the drawbacks of the measurement method used in the shoulder are not eliminated, and, consequently, leads to incorrect conversion of the blood pressure signal in patients with severe rhythm disturbances and pronounced pressure variation.

The devices of the company Finapres [12] use the global transfer function from the finger pressure to the shoulder pressure. During the operation of the instrument, the setup of the photoplethysmographic signal is carried out without repeated measurement in the shoulder - “Physiocalibration”. The humeral cuff allows you to receive only the value of the SAD using the “return to flow” method. Not interrupting the measurement in the finger, the humeral cuff in the same arm is pumped to a pressure level exceeding the CAD. Finger pressure pulsations disappear. The pressure in the humeral cuff is reduced at a controlled rate until pulsations appear in the finger cuff. The procedure is repeated. Disadvantages is the ability to measure only the MAP; pressure in the shoulder is measured at a different time than the corrected signal; single values of pressure are recorded, which does not allow to determine blood pressure in patients with a strong rhythm disturbance and pronounced pressure variation; measurement on one hand leads to a change in hemodynamics.

The aim of the present invention is to create a device that produces a numerical estimate in each heartbeat of blood pressure, comparable to the measurement of blood pressure by the Korotkov method in the shoulder.

The technical result of the claimed invention is to increase the functionality of the device while improving the accuracy of blood pressure measurements by obtaining the ability to measure blood pressure on each cycle of heartbeat, which will continuously monitor blood pressure in patients, especially when a rhythm disturbance.

This technical result is achieved due to the fact that the device for determining blood pressure in the shoulder at each heartbeat includes a Korotkoff tone block containing a sound vibration sensor and a shoulder cuff, at least one pressure control unit, a block of continuous non-invasive blood pressure measurement, a processing unit and control, information display device, wherein the processing and control unit is connected with a sound vibration sensor capable of detecting tones Korotkova, with a pressure control unit connected to the shoulder cuff, with a continuous non-invasive blood pressure measurement unit, with a display device, and configured to control the pressure control unit and receive and process data from the sound vibration sensor and the continuous non-invasive blood pressure measurement unit and further ensure the conversion of the measured continuous blood pressure so that the time of intersection of the anacrot pulse during The pressure curve in the humeral cuff corresponded as closely as possible to the instants of time for the appearance of Korotkoff tones, and for determining the systolic and diastolic blood pressure values at each heartbeat.

In this case, the possible options for the development of the main technical solution, namely, that:

- block continuous non-invasive blood pressure measurement made with the possibility of measuring blood pressure by the method of the unloaded artery;

- a block of continuous non-invasive blood pressure measurement using the unloaded artery method contains a photoplethysmographic system connected to the processing and control unit and combined with a compression finger cuff connected to the pressure control unit;

- block continuous non-invasive blood pressure measurement made with the possibility of measuring blood pressure applanation method;

- unit of continuous non-invasive blood pressure measurement applanation method contains a strain gauge connected to the processing and control unit and configured to be located above the radial artery, and a device transmitting pressure to the strain gauge connected to the pressure control unit and arranged to be located on the wrist or temple;

- block continuous non-invasive measurement of blood pressure made with the possibility of measuring blood pressure by the speed of the pulse wave;

- a block of continuous non-invasive blood pressure measurement according to the speed of the pulse wave contains a photoplethysmographic sensor and an ECG sensor connected to the processing and control unit and arranged to be located on the part of the patient’s body selected for blood pressure measurements;

- the processing and control unit performs the conversion of the resulting continuous blood pressure using a linear function;

- the processing and control unit converts the resulting continuous blood pressure using a non-linear function;

- there is a level sensor connected to the processing and control unit.

Thus, due to the combination of the claimed essential features, it is possible to increase the functionality of the device while simultaneously improving the accuracy of blood pressure measurements by determining the blood pressure in the shoulder at each heartbeat by converting data obtained during simultaneous removal of sound vibrations (Korotkoff tones) from the patient during occlusion of the shoulder patient’s one hand, and data obtained from continuous non-invasive blood pressure measurement on another part of the patient’s body according to the control algorithm in the tracking mode. As a result, blood pressure is calculated not by the boundaries of the appearance or disappearance of Korotkov’s tones, but directly by determining in each heartbeat the maximum (systolic) and minimum (diastolic) values from the resulting continuous pressure curve.

The essence of the invention is illustrated by the figures and the following description.

FIG. 1 is an illustration of the conversion of a continuously measured blood pressure.

FIG. 2 shows the block diagram of the device in paragraphs 2 and 3 of the formula.

FIG. 3 shows the block diagram of the device in paragraphs 4 and 5 of the formula.

FIG. 4 shows the block diagram of the device in paragraphs 6 and 7 of the formula.

FIG. 5-7 presents an example of the use of the device.

FIG. 8-10 shows another example of the use of the device.

The method for determining blood pressure in the shoulder at each heartbeat (Fig. 1) consists in performing periodic occlusion of the patient’s shoulder with a shoulder cuff, pressure recording in the shoulder cuff and recording of Korotkoff tones using a sound vibration sensor. At the same time, a continuous non-invasive measurement of blood pressure is made on another part of the patient's body.

Then, using the data obtained, using the processing and control unit, they transform the pressure measured continuously in another part of the body so that the time of the anakrot intersection (rises in the initial part of the pulse wave) of the pulse waves 1 with pressure curve 2 in the shoulder cuff most closely correspond to the time of occurrence tones 3 Korotkova (Fig. 1). The specified transformation is carried out by shifting and scaling the amplitude of the original pulse waves 1 to obtain the converted pulse waves 4, the ankrots of which intersect the pressure curve 2 at the instants of time that most closely correspond to the instants of Korotkoff tones 3.

According to the continuous BP values obtained as a result of the conversion, the SBP and DBP values in each heartbeat are also determined using the processing and control unit.

FIG. 1 are indicated: T _u1, T _{and n u2} ... T - measured instants of occurrence VCM 6 3 Korotkoff tones; T _p1 , T _p2 ... T _pk are the calculated times of intersection of the anacrot initial pulse waves 1 with pressure curve 2; T ^p _p1 , T ^p _p2 ... T ^p _pm are the calculated times of intersection of the anakrot of the converted pulse waves 4 with the pressure curve 2.

To implement this method of determining blood pressure in the shoulder on each heart applied device (Fig. 2-4), which includes a block of 5 Korotkov tones (BTK), contains a sensor 6 sound vibrations (S / V) and a shoulder cuff 7 (PLM), at least one pressure control unit 8 (BUD), continuous non-invasive blood pressure measurement unit (BNNIAD) unit 9, processing and control unit 10 (C & D), level sensor 11 (DU), information display device 12 (CIO).

At the same time, the spare wheel assembly 6 is a microphone and is made with the possibility of registering Korotkov tones, connected to the power supply unit 10, and can be combined with the PLM 7.

The ECU 8 is connected to the ACU 10 and is, for example, a pneumatic device for inflating compression cuffs with air. And if there are several cuffs, then such a block for each cuff can be separate or common. As the ECU 8, a device can also be used to create a mechanical pressure on a part of the patient’s body.

PLM 7 can be made of compression or have a mechanical mechanism for squeezing the patient’s shoulder, it is connected to the ECU 8 and configured to be placed on the patient’s shoulder.

BNNIAD 9 is connected to BOU 10 and can be made with the possibility of measuring blood pressure by the method of an unloaded artery (Fig. 2) or by applanation method (Fig. 3) or by the pulse wave velocity (Fig. 4).

FIG. 2 shows an example of BNNIAD 9, which implements the unloaded artery method, which contains a photoplethysmographic system 13 (FPS) connected to BOI 10 and combined with a compression finger cuff 14 (CWP) connected to BUD 8. The principle of this method is well known [3].

In case BNNIAD 9 implements an applanation method (Fig. 3), it contains a strain gauge sensor 15 with a spherical surface (TD) connected to BOI 10 and configured to be located above the radial artery, and a pressure transfer device (DFC) 16 on the TD 15 (in this case, mechanical pressure is used) associated with the ECU 8 and made with the possibility of its location on the wrist or temple. The principle of implementation of this method is well known [9].

If BNNIAD 9 implements the method of determining blood pressure by the pulse wave propagation speed (Fig. 4), it contains a photoplethysmographic sensor 17 (FPD) and an ECG sensor 18 (DECG) connected to BOI 10 and configured to position them on a part of the patient's body selected for the measurement of blood pressure. The principle of implementation of this method is well known [10].

Remote control 11 is connected to BOU 10 and configured to determine the position of the patient’s body part relative to his heart. Its presence is not mandatory, but is desirable for more accurate measurements.

WAI 12 is connected to BOI 10 and is a display for visualizing the results of determining blood pressure.

BOUU 10 is a programmable controller and can be implemented on the basis of a personal computer. This BOUU 10 is made with the ability to control the ECU 8 and with the ability to receive and process data from the DZK 6 and BNNIAD 9, as well as with the ability to ensure the conversion of measured continuously BP.

When processing data in BOUU 10, the characteristic tones corresponding to heartbeats (Tones of 3 Korotkov) are distinguished from the registered sound-wheel assembly of a sound signal 6. For each tone 3, the time of its occurrence and amplitude is determined, and Korotkov's tones 3 occur at the moment when the pressure in the brachial artery during its growth is compared with the pressure in PLM 7. The transformation is carried out so that the time of intersection of the anacrot pulse waves 1 with curve 2 The pressures in PLM 7 corresponded as much as possible to the instants of time when the Korotkov tones 3 appeared (Fig. 1). This transformation is carried out by shifting and scaling the amplitude of the original pulse waves 1 to obtain the converted pulse waves 4, the anacrots of which intersect the pressure curve 2 at time points that most closely correspond to the time of occurrence of Korotkoff tones 3.

The conversion of pulse waves 1 is carried out in such a way that the calculated time points (T ^p _p1 , T ^p _p2 ... T ^p _pm ) intersection of the anakrot of the converted pulse waves 4 with the pressure curve 2 maximally coincided with the moments of occurrence (T _{и 1} , T _{и 2} ... T and _n ) measured DZK 6 tones 3 Korotkova.

Conversion of the resulting continuous blood pressure can be performed in BOI 10 using a linear function:

P (t) _pl = P (t) _nor * k + Δ _p ,

where P (t) _pl is the pressure in the shoulder, P (t) _nor is the pressure continuously measured on another part of the body, k is the gain, Δ _p is the magnitude of the shift.

Conversion of the resulting continuous blood pressure can be performed in BOI 10 also using a nonlinear function, for example [13]:

where i is the imaginary unit.

и коэффициентом демпфирования D<1.This transformation is equivalent to amplification (k), the use of a second-order high-pass filter with amplification (with a cut-off frequency f ₀ ) and a second-order low-pass filter with a resonant frequency

and the damping coefficient D <1.

Conversion to BOUU 10 is performed in such a way that the objective function applied to the obtained time points F (T _{и i} , T ^п _р1 ) _{reaches an} optimum with the best match of the parameters of measured and calculated Korotkova tones 3, and the continuous pressure obtained in this case will correspond to HELL in the arm .

Based on the resulting conversion values of blood pressure, measured continuously, also using BOiU 10 determine the values of the GARDEN and DBP in each heartbeat. As a result, blood pressure is calculated not by the boundaries of the appearance or disappearance of Korotkov’s tones, but directly by determining in each heartbeat the maximum (systolic) and minimum (diastolic) values from the resulting continuous pressure curve.

The inventive device is used as follows.

Placed on the shoulder of one arm of the patient PLM 7 and place the spare wheel bracket 6 on the projection of the brachial artery in the cubital fossa.

If the unloaded artery method (Fig. 2) is selected as the method of continuous blood pressure measurement, then the FPS 13 and KPM 14 are placed on the finger of another part of the patient’s body (second hand). External pressure is produced in accordance with the photoplethysmogram signal used in the FPS feedback circuit 13 with BOUU 10, so that the blood filling of the vessels of the finger corresponds to the maximum level. Fulfillment of this condition, in accordance with the Penaz principle, ensures the equality of the external pressure and the measured parameter of blood pressure, and allows continuous measurement of blood pressure in the finger vessels.

If the applanation method (Fig. 3) is selected as the method of continuous blood pressure measurement, then TD 15 is placed on the wrist of the other hand over the radial artery or on the temple. On the TD 15, by means of a mechanical drive, the external pressure is applied through CLC 16 to maximize pressure pulsations. Maximum pulsations occur when the mean pressure inside the vessel is equal to the pressure outside. Based on the third law of Newton, the pressure inside is directly proportional to the force that causes the spherical surface to flatten and indirectly proportional to the contact area, which allows measuring blood pressure based on the signal from TD 15.

If the method of pressure measurement using the pulse wave velocity (Fig. 4) is selected as the method of continuous pressure measurement, then the FPD 17 is placed on the finger and an ECG with DECG 18 is simultaneously recorded. The calculation of blood pressure for each heartbeat is based on the pulse wave propagation time determined by ECG and photoplethysmographic signal from a finger.

Simultaneously with continuous pressure measurement, pressure is periodically increased in PLM 7 above the CAD level and controlled linear pressure release. Using BOUU 10 fix the audio signal from the spare wheel bracket 6, located distal to the place of occlusion.

Next, perform the processing and conversion of the data, thus determining the blood pressure in the shoulder at each heartbeat.

Example 1

FIG. 5 shows a patient record with high variability of pressure. Both measurements by the classical Korotkov method coincided with the moments of a low CAD, which made it possible to make a false conclusion that the average value of the CAD corresponds to the norm (126.5 mm Hg). According to continuous data, the value of the AAD varied in the range from 124.5 to 152.5 with an average value of 135.1 mm Hg, which is an elevated pressure. FIG. 6 shows an enlarged first dimension of FIG. 5, and in FIG. 7 shows an enlarged second dimension of FIG. 5. Measurement data are summarized in Table 1.

Example 2

FIG. 8 shows the patient record with ventricular extrasystole. Non-uniform Korotkov tones are observed, which makes it difficult to determine the pressure by the classical method. The value of the AAD was varied in the range from 110.2 to 179 with an average value of 145.2 mm Hg, the DBP value changed in the range from 41.9 to 117.7 mm Hg. with an average of 84.4 mm Hg. FIG. 9 shows an enlarged first dimension of FIG. 8, and in FIG. 10 shows the enlarged second dimension of FIG. 8. Measurement data are summarized in Table 2.

List of sources used:

1. Short N.S. On the issue of blood pressure testing methods // News of the Imperial Military Medical Academy. - 1905. - T. 11. - p. 365-367.

2. Williams B. et. al. 2018 ESC / ESH Guidelines for the management of arterial hypertension // European Heart Journal. - 2018. - V. 39. - p. 3021-3104.

J. Patentova Listina, CISLO 133 205. - 19693

J. Patentova Listina, CISLO 133 205. - 1969

4. Penaz. Automatic noninvasive blood pressure monitor. US 4869261. Prior. 03/27/1987. Publ. 09/26/1989.

5. Inflatable finger cuff. US 4726382 and EP 0260807 application EP 19870307192 from 09/14/1987, publ. 03/23/1988.

6. Inflatable finger cuff for use in non-invasive monitoring of instantaneous blood pressure. Europ. pat. application №0537383; Application number: 91202676.2; Date of filing: 10/15/91; Applicant: Nederlandse organisatie TNO. 04/21/93 Bulletin 93/16.

7. Inflatable finger cuff. US 4,726,382. Prior. 02/23/1988.

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Claims (10)

1. A device for determining blood pressure in the shoulder at each heartbeat, comprising a Korotkoff tone block, containing a sound vibration sensor and a shoulder cuff, at least one pressure control unit, a continuous non-invasive blood pressure measurement unit, a processing and control unit, a display device , wherein the processing and control unit is connected with a sound vibration sensor, which is capable of detecting Korotkoff tones, with a pressure control unit connected to a lip cuff with a continuous non-invasive blood pressure measurement unit, with a display device, and configured to control the pressure control unit and receive and process data from the sound vibration sensor and the continuous non-invasive blood pressure measurement unit and further ensure the conversion of the continuously measured blood pressure in this way so that the time of the intersection of the anacrot pulse waves with the pressure curve in the humeral cuff tstvovali time instants of occurrence of the Korotkoff sounds, and determining the systolic and diastolic blood pressure for each heartbeat. 2. The device according to claim 1, characterized in that the block of continuous non-invasive blood pressure measurement is made with the possibility of measuring blood pressure by the unloaded artery method. 3. The device according to claim 2, characterized in that the block of continuous non-invasive blood pressure measurement using the unloaded artery method comprises a photoplethysmographic system connected to the processing and control unit and combined with a compression finger cuff connected to the pressure control unit. 4. The device according to claim 1, characterized in that the block of continuous non-invasive measurement of blood pressure is made with the possibility of measuring blood pressure by applanation method. 5. The device according to p. 4, characterized in that the block of continuous non-invasive blood pressure measurement applanation method contains a strain gauge connected to the processing and control unit and made with the possibility of its location above the radial artery, and the device transmitting pressure to the strain gauge associated with pressure control unit and made with the possibility of its location on the wrist or temple. 6. The device according to claim 1, characterized in that the block of continuous non-invasive measurement of blood pressure is made with the possibility of measuring blood pressure by the pulse wave velocity. 7. The device according to claim 6, characterized in that the block of continuous non-invasive blood pressure measurement of the pulse wave speed contains a photoplethysmographic sensor and an ECG sensor connected to the processing and control unit and configured to be located on the patient’s body part selected for measurement blood pressure. 8. The device according to claim 1, characterized in that the processing and control unit converts the continuous blood pressure obtained using a linear function. 9. The device according to claim 1, characterized in that the processing and control unit performs the conversion of the resulting continuous blood pressure using a nonlinear function. 10. The device according to p. 1, characterized in that it contains a level sensor connected to the processing and control unit.

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