RU2327414C1 - Method of blood pressure measurement based on three-dimensional compression oscillogram - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: compressing measuring cuff is applied to limb of patient. Applied pressure scaling-up diagram is registered measuring diastolic, systolic and average blood pressure by main artery pulsation. To measure diastolic blood pressure two straight lines are drawn: one is horizontal by diastolic oscillation ends of cuff pressure-free limb vessels, and another is drawn by diastolic oscillation ends of cuff pressure-bearing main artery from average pressure level to upward and left bias to cross horizontal straight line. Systolic blood pressure of both healthy and sick persons is calculated by original formula.

EFFECT: high accuracy and simplification of blood pressure measurement.

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Description

The technical field to which the invention relates.

The invention relates to medicine and can be used in determining blood pressure (BP) in healthy and sick people.

State of the art

There is a method of determining blood pressure by listening (recording) tones Korotkova (In the book. "Transactions of the Military Medical Academy", 1905, v. II, No. 9, 365 pp.), Arising from compression of the brachial artery with a pinch cuff.

The known method has a number of methodological and instrumental disadvantages.

The most significant methodological drawback is that the origin of Korotkov tones has not yet been studied, and the errors in determining blood pressure by this method reach tens of mmHg. Art. (Russian Medical News, 2006 No. 2, p. 62-70).

Instrumental shortcomings include the need for rigorous installation of the microphone over the projection of the artery and the high sensitivity of the method to external noise interference.

A known method of determining blood pressure by oscillations of an artery during its compression by the cuff (Functional Diagnostics, 2003, No. 1, p. 56-64).

The method also has methodological and instrumental disadvantages.

The main methodological disadvantage is that the algorithm for deciphering blood pressure indicators in this method is adapted to Korotkov’s tones (Arterial hypertension. Recommendations of the World Health Organization and the International Society of Hypertension. M., 1999). Instrumental errors include the artificial suppression of the low-frequency components of the waveform, which is done in order to increase the noise immunity of the registration of oscillations.

Closest to the proposed method for determining blood pressure is "The method of compression volumetric oscillometry (OKO) indicators of the circulatory system" (Eurasian patent No. 003497, 2003), including the registration of the pulse curves of blood vessels in the process of changing the pressure in the pinch measuring cuff imposed on the limbs of the subject , followed by electrical and graphic conversion, characterized in that in it initially in the process of increasing pressure in the pinch cuff in the frequency range from approximately At 0 to 50 Hz, with a linear horizontal amplitude-frequency characteristic and a linear amplitude characteristic throughout the conversion and amplification path, a graph of the linear increase in the applied pressure and the venous-arterial oscillometric curve are recorded, then, continuing the compression of the cuff to 200-300 mm RT. Art., record the oscillometric curve of the arterial pulse, the obtained pulse curves determine the values of diastolic, mean, systolic and final systolic pressure, respectively, venous and arterial, and a number of other indicators of the arterial system.

However, the known method also has significant methodological disadvantages.

The main methodological disadvantage is that pulsation of the main, for example, brachial, artery is taken as the only source. Meanwhile, smaller vessels pulsate during compression of the hand: arterioles, metarteriols and terminal arteries (Human Physiology. Edited by R. Schmidt and G. Tevs. M: Mir, 1986, vol. 3, p.118). As a result, diastolic blood pressure (ADD) is determined with an error, since pulsations of arterioles or terminal arteries are taken as its point on the JCE.

The second main methodological disadvantage is that the healthy person takes the last maximum positive oscillation on the DCE as the systolic blood pressure point (BPA), meanwhile, after a complete clamping of the artery during diastole at the point of average blood pressure (BPA), most patients undergo changes in the tone of the walls arteries that distort the contour of the curve, and the sign proposed to determine the ADS by the last maximum oscillation is false.

The third main methodological drawback is that the determination of blood pressure in patients with hypertension by changing (decreasing) the rate of rise of the anacrotic part of the oscillation curve is also erroneous and does not correspond to its actual value.

The fourth main methodological disadvantage is that the method proposed in the known method for determining the ABP by the integral values of the pulse wave refers to the portion of the oscillometric curve to the diastolic blood pressure, i.e. in the zone of pulsation of arterioles, metarteriol and terminal arteries, while ADS is determined by the main artery by pulsations free from pulsations of small arteries.

The fifth main methodological disadvantage is that when calculating the final systolic blood pressure (ADK), a straight line is used that runs from the last maximum oscillation down and to the right along the systolic ends of the oscillation to its intersection with the line also passing along the systolic ends of the oscillation after a sharp decrease in their amplitude due to the complete compression of the artery in systole, while the possibility of determining the true maximum oscillation due to changes in the tone of the walls of the arteries is lost.

SUMMARY OF THE INVENTION

The objective of the present invention is to develop the most reasonable and accurate method of measuring blood pressure, free from the disadvantages of the known method. The problem is achieved in that, in contrast to the known method for determining blood circulation parameters by volume-compression oscillometry, including registration of the pulse curves of blood vessels in the process of increasing pressure in a pinch measuring cuff superimposed on the limb of the subject, followed by electrical and graphic signal conversion in the frequency range from approximately 0 to 50 Hz and a linear horizontal amplitude-frequency characteristic and linear amplitude eristikoy across the path of transformation and amplification of the signal, registering the schedule upramping applied pressure and venous-arterial oscillometric curve, then, continuing the compression cuff to 200-300 mm Hg. Art., record the oscillometric curve of the arterial pulse, using the obtained pulse curves determine the values of diastolic, mean, systolic and final systolic pressure, respectively, of the venous and arterial and a number of other indicators of the arterial system, along with the registration of the OKO to ADx, signs of pulsation of the main artery are determined, points are found coinciding with the ADD and ADsr, to determine the ADS on the oscillations of the main artery between the points coinciding with the ADD and ADsr, substitute the values of ADD and ADsr determined by OKO, find the dimension of blood pressure fluctuations in the cardiac cycle in mm RT. Art., multiply the amplitude of the oscillations by the found ripple dimension.

Brief Description of the Drawings

Figure 1 represents the oscillogram of the subject K. with hypertension of the 2nd degree. Errors in determining the pressure values are known and proposed method. In connection with an increase in the tone of the artery walls when it is clamped at the point of the ADcr, the oscillation amplitude immediately decreases, and therefore signs of determining the arterial arterial velocity from the last maximum oscillation or a change in the rate of increase of anacrote are lost.

Figure 2 represents the oscillogram of the examined Z. with isolated hypertension. Errors in the measurement of arterial pressure are also associated with a change in the tone of the arteries and an incorrect determination of the blood pressure at the beginning of the deviation of the oscillations down from the isolines, which are due to pulsation not of the main artery, but of arterioles, metarteriol.

Figure 3 is a graph of the determination of the ADS by the oscillations in the section of the curve between the ADD and ADSR. Details in the text.

The implementation of the invention.

The method for determining blood pressure by volumetric compression waveform is as follows.

A pinch measuring cuff is put on the limb of the subject (for example, the shoulder), into which air is supplied under increased pressure at a speed of 3-5 mm / s. To avoid distortion of the oscillations due to the transfer pulsation of the veins, the arm is brought to the body. The distal edge of the cuff is set 2.5-3 cm above the ulnar fossa.

In contrast to the known method, two straight lines are drawn for the determination of t. ADD on the DCO: the first along the diastolic ends of the oscillations preceding the beginning of the pulsation of the arterioles (t. A), the second - along the diastolic ends of the oscillations from t. ADsr up and to the left until it intersects with first. The intersection point of the lines corresponds to ADD. After reaching a pressure in the cuff equal to ADav, the artery at the end of the diastole is completely compressed, and as the pressure in the cuff further increases, the compression force and its duration increase. In response, the tone of the walls of the arteries increases, and then the last maximum oscillation may become the next after the oscillation, which coincides with the ADsr, after which a progressive decrease in the amplitude of the oscillations in the systole develops under the influence of an increasing spasm of the walls of the arteries, which reduces the amplitude of their opening when another pulse wave arrives (Fig. .one). In these cases, the so-called ADS is located in the region of oscillations decreasing in amplitude, without a clear sign. Also, the sign of a change in the rate of rise of the anacrotic wave is lost, by which it is proposed in the known method to determine the ADs.

Since the sign of the last maximum oscillation is lost due to the deformation of the waveform associated with its response to compression after ADP, the final blood pressure is determined by reaching the horizontal level of the diastolic part of the waveform, which coincides with a sharp decrease in the amplitude of the oscillations resulting from a side impact of the blood column o the proximal part of the measuring cuff after full clamping of the artery.

Difficulties in the determination of blood pressure in many healthy and sick subjects after reaching a pressure in the cuff of blood pressure and above are associated with wave-like changes in the amplitude of the oscillator curve (Fig. 2), which also arise due to changes in vascular tone and also make it impossible to determine blood pressure in a known manner .

To determine the ADS by the proposed method, the measured oscillation by the proposed method according to the proposed method on the oscillations under study is measured at the level of the beginning of the anacrot; at the approximate level of ADsr, the values of ADs measured by the OKO are put down (Fig. 3). After that, blood pressure is calculated by a formula similar to the formula for calculating blood pressure when measuring blood pressure using the direct method:

where: blood pressure, blood pressure and blood pressure respectively systolic, diastolic and mean blood pressure,

and - the amplitude of the oscillations from the level of diastolic pressure to the level of average pressure.

b is the oscillation amplitude from the average pressure level to the oscillation peak;

In the central arteries, the brachial artery, like the aorta, belong to this group, and the arterial pressure with sufficient accuracy can be calculated by the formula:

This method of determining blood pressure is much simpler than by formula 1 and is fully comparable with the determination of blood pressure by direct method.

Dividing (ADsr - ADd) by a, we get the dimension of the oscillations in mmHg. century, multiplying the amplitude of the oscillation b by this value and adding it to the ADSr, we obtain the ADS.

The proposed method for determining ADS is universal and coincides in its values with the measured direct method of ADS with the introduction of a catheter into the brachial artery.

As an illustration, table 1 presents data on the determination of blood pressure by the proposed method and the calculation formula.

Table 1 Comparison of the results of the determination of blood pressure by the proposed method and by the calculation formula in subjects examined, according to the values of arterial pressure, to different categories according to the classification of the WHO SIDS, 1999 (mmHg) Categories Norm Hypertension Optim. Norm Increase Normal Soft Moderate Heavy Isolir. systole. According to the suggestion method 108,0 116.0 122.0 133.0 141.0 151.0 127.0 According to the formula 108,0 115.0 121.0 134.0 142.0 153.0 128.0 Number of examined 111 86 one hundred 123 67 63 106 Number of measurements 196 120 144 231 122 126 213

Thus, according to the proposed method, the volumetric compression oscillogram can be used to determine with high accuracy not only the arterial pressure in the brachial artery, but also in the aorta, which was previously not feasible.

The advantage of the proposed method and the higher accuracy of measuring blood pressure according to it are shown in tables 2, 3 and 4. As examples, the data are given for determining blood pressure according to OKO known (I) and proposed methods (II) in a healthy person and patients with moderate and severe hypertension .

table 2 Blood pressure determined by the known (I) and proposed (II) methods in a healthy person, mmHg Art. Way ADD ADSR ADs Adx ADP Adud I 56 82 92 130 36 38 II 54 82 115 134 61 19 Δ +2 0 -23 -four -35 +19

Table 3 Blood pressure determined by the known (I) and proposed (II) methods in patient P. with moderate hypertension, mm RT. Art. Way ADD ADSR ADs Adx ADP Adud I 84 108 124 178 40 54 II 80 108 146 185 66 39 Δ +4 0 -22 -7 -16 +15

Table 4 Blood pressure determined by the known (I) and proposed (II) methods in patient M. with severe hypertension, mmHg Art. Way ADD ADSR ADs Adx ADP Adud I 78 121 132 186 54 54 II 97 121 154 200 57 46 Δ -19 0 -22 -fourteen -3 +8

From the presented material it can be seen that in a healthy person the error in determining blood pressure in a known manner reached 23 mmHg. Art. The error in determining the pulse ADP, calculated as the difference between the blood pressure and the blood pressure, was -35 mm RT. Art. The error in determining ADud calculated as the difference in ADK-ADs was +19 mm Hg. Art. In a patient with moderate hypertension, the error of the known method for blood pressure and blood pressure was approximately the same, respectively -22 and +15 mm RT. Art. In a patient with severe hypertension, the error in the determination of blood pressure was at the same level of -22 mm RT. Art., however, significantly increased the error in the determination of ADD (-19 mm RT. Art.)

The same and even large errors in determining blood pressure in a known manner are visible in FIGS. 1, 2, where also the blood pressure values measured in a known manner are indicated by I, and by the proposed method, by II. On the OKO in figure 1 they reached for ADD 9 mm RT. Art., for blood pressure 30 mm RT. Art., for ADx 27 mm RT. Art., figure 2, respectively - 30, 26 and 36 mm RT. Art.

Thus, the presented method allows with high accuracy to determine all values of blood pressure. The use of oscillations preceding BPA to determine BP is a fundamentally new way of determining BP by the non-invasive method using the pinch cuff, free from errors in blood pressure determination due to a change in the tone of the walls of the pinch artery under the influence of its compression by the pressure created in the cuff during measurement. This method makes it convenient to measure the pressure during daily monitoring, since hand compression can be limited by the value of ADav, which is 40-50% lower than in existing monitors, which is especially important for examining young children.

Claims (1)

A method for determining blood pressure, including applying a pinch measuring cuff to the limb of the subject, recording a graph of a linear increase in the applied pressure, while diastolic, systolic and mean arterial pressure are determined by pulsation of the main artery of the limb, characterized in that two straight lines are built to determine diastolic blood pressure: one horizontal - along the diastolic ends of the oscillation of the pressure-cuffed limb vessels, second uy - according to the diastolic ends of the oscillations of the pressure loaded in the cuff of the main artery from the level of the average pressure obliquely up and to the left to the intersection with the horizontal line, and systolic blood pressure, both in healthy and sick people, is determined by the formula АДс = b (АДср-АДд) / а + АДср, where a is the amplitude of the oscillations from the level of diastolic pressure to the level of average pressure, b is the amplitude of the oscillations from the average pressure to the peak of the oscillation.

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