CN115886767A - Hemodynamics platform measuring method - Google Patents

Abstract

A hemodynamics platform measuring method is characterized in that a pulse wave of a person to be measured is measured by keeping a constant pressure on a measuring platform with the pressure of a blood pressure belt of an electronic sphygmomanometer in a range of 55-70 mm Hg, at least one pulse wave is captured from a plurality of measured pulse waves, and the heart stroke quantity is calculated by matching the waveform and characteristic point parameters of each pulse wave with the systolic pressure and diastolic pressure of the blood pressure of the person to be measured; the invention can change the pressure of the measuring platform by selecting the pressure of the measuring platform in a proper interval of 55-70 mm Hg in cooperation with the diastolic pressure and the physiological condition of different testees and the signal quality of the electronic sphygmomanometer, so that each tester can obtain a typical pulse waveform by proper measuring platform, the accuracy of the measuring result is improved, and the proportion of people who cannot be measured is reduced.

Description

Hemodynamics platform measuring method

Technical Field

The present invention relates to a measurement method, and more particularly, to a measurement method for a hemodynamic platform.

Background

Monitoring of hemodynamics is a very important therapeutic activity for cardiovascular diseases, and parameters such as Cardiac Output (CO) refer to the total volume of blood ejected by a unilateral ventricle per minute, which is the product of Heart Rate (HR) and Stroke Volume (SV), and is an important indicator reflecting heart function; through monitoring of the hemodynamics, clinical medical staff can be provided to identify the causes of diseases early, proper medical treatment is given to patients timely, and the death rate of heart patients is reduced.

The current techniques for monitoring cardiac output include invasive and non-invasive techniques, such as cardiopulmonary volume monitoring (PiCCO), based on the principle of placing a central venous catheter and an arterial catheter in a human body by pulmonary thermodilution and pulse curve analysis, injecting a certain amount of ice water from the central venous end, and measuring the temperature and time variation line at the arterial end, thereby measuring the cardiac output.

Non-invasive cardiac output detection techniques such as cardiac impedance-based blood flow graph (ICG) are performed by measuring electrodes disposed at two ends of a tissue thorax to obtain a cardiac impedance-based blood flow graph, and substituting parameters thereof into a kubicek stroke volume formula to calculate Cardiac Output (CO); the non-invasive cardiac output detection also adopts a pulse wave-based method, which is to calculate the Cardiac Output (CO) by using pulse wave signals, waveforms and characteristic points of the waveforms after obtaining the pulse waves by using a pressure pulse device based on an elastic organ Model (Windkessel Model). The non-invasive measurement method has the advantages of no wound, safety, simplicity and convenience compared with the invasive method, but the method for calculating the cardiac output by using the pulse wave has the advantages that whether the waveform of the pulse wave typically shows various characteristic points is related to the pressure applied to the pulse pressing belt, so that the selection of the proper platform pressure for measuring the pulse wave is very important for the measurement result, the accuracy is reduced due to over-high or over-low pressure, and the number of people who can be measured by using the method is reduced.

Disclosure of Invention

The accuracy of the conventional method for calculating cardiac output by using pulse wave is related to the pressure of the selected measuring platform. Therefore, the invention arranges the measuring platform in a better pressure interval, and the pulse wave of the person to be measured is measured by the measuring platform at a fixed pressure, thereby achieving the purposes of improving the accuracy of the measuring result and reducing the proportion of people who cannot be measured.

To achieve the above objects, the present invention provides a method for measuring a hemodynamic platform, the method comprising:

the measuring platform measures pulse waves: inflating a pulse pressing belt of an electronic sphygmomanometer to a measuring platform with the pressure of 55-70 mm Hg, keeping the pressure on the measuring platform for a set time by fixing the pressure, measuring pulse waves of a person to be measured, and capturing at least one pulse wave from a plurality of measured pulse waves, wherein the waveform of each pulse wave has characteristic points such as a highest point, a maximum slope point, a turning point, a lowest point and the like according to a time sequence;

measuring blood pressure: measuring the systolic pressure and the diastolic pressure of the blood pressure of the person to be measured; and

calculating stroke volume using the measurement parameters: the waveform of each pulse wave and the parameters of each characteristic point of the waveform are matched with the data of systolic pressure and diastolic pressure to calculate the heart beat volume.

Furthermore, after the step of measuring the pulse wave by the measuring platform, the electronic sphygmomanometer keeps the pressure of the tourniquet to continuously inflate the tourniquet, and the step of measuring the blood pressure of the person to be measured is carried out.

Furthermore, the step of measuring the blood pressure is prior to the step of measuring the pulse wave by the measuring platform, and the step of measuring the pulse wave by the measuring platform is carried out after the step of measuring the blood pressure is finished.

Furthermore, the present invention further comprises a step of measuring the heartbeat, wherein the heartbeat rate of the person to be measured is measured, and in the step of calculating the heartbeat volume by using the measurement parameters, the cardiac output of the person to be measured is obtained by multiplying the heartbeat volume by the heartbeat rate.

Further, the Stroke Volume (SV) is calculated according to the following formula:

wherein the highest point T _sys (P _sys ,t _sys ) Maximum slope point T _inst (P _inst ,t _inst ) Turning point T _dic (P _dic ,t _dic ) Lowest point T _dia (P _dia ,t _dia )。

Compared with the prior art, the invention has the beneficial effects that:

the measuring platform for measuring the pulse wave is in a proper interval of 55-70 mm Hg, the pressure of the measuring platform can be changed by matching with the diastolic pressure and the physiological condition of different testees and the signal quality of the electronic sphygmomanometer during measurement, so that each tester can obtain a typical pulse wave form by the proper measuring platform, and the effects of improving the accuracy of a measuring result and reducing the proportion of people who cannot be measured are achieved.

The step of measuring the blood pressure can be carried out immediately after the step of measuring the pulse wave by the measuring platform, or the two steps can be carried out separately at different time or sequentially exchanged, and the invention has the further effects that if the step of measuring the pulse wave by the measuring platform is followed by the step of inflating the tourniquet to carry out the step of measuring the blood pressure, the pulse wave waveform parameters, the heart rate and the blood pressure which need to be calculated by the cycle measurement of one-time inflation and deflation of the tourniquet can be measured, and the efficiency of measuring the heart beat quantity is accelerated.

Drawings

FIG. 1 is a flow chart of the steps of the preferred embodiment of the present invention.

FIG. 2 is a graph of pressure versus time for the measurement platform and blood pressure measurement in accordance with the preferred embodiment of the present invention.

FIG. 3 is a pressure time graph of a pulse waveform according to a preferred embodiment of the present invention.

Description of the symbols:

a main wave and B heavy wave

T _sys Highest point T _inst Point of maximum slope

T _dic Turning point T _dia Lowest point

Tau time constant X measuring platform

S01-S04 steps

Detailed Description

So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings.

As shown in the flowchart of fig. 1, a preferred embodiment of the present invention provides a hemodynamic platform measurement method, which comprises the steps of:

(S01) the measuring platform measures the pulse wave: as shown in fig. 2, the pulse pressure band of an electronic sphygmomanometer is inflated to a measurement platform X with a pressure of 55 to 70 mm hg (mmHg), in the preferred embodiment, 65 mm hg is selected as the measurement platform X, and the platform pressure of 65 mm hg is kept on the measurement platform X for a set time, for example, 8 seconds, within which the pulse wave measurement is performed on the subject; in the preferred embodiment, one of the pulse waves having a typical waveform is extracted, the waveform of the pulse wave plotted with the horizontal axis as unit time and the vertical axis as pressure is shown in fig. 3, the waveform of the pulse wave is divided into a main wave a and a dicrotic wave B corresponding to the systolic period and the diastolic period before and after the main wave a, and the main wave a and the dicrotic wave B have a highest point T at the top of the main wave a in time sequence _sys Maximum slope point T with maximum slope in waveform _inst A turning point T between the main wave A and the dicrotic wave B _dic And a nadir T at the end of the dicrotic wave B _dia And (5) waiting for characteristic points.

The typical pulse wave is the turning point T between the main wave A and the dicrotic wave B _dic Has obvious turning point, when the selected inflation pressure of the blood pressure belt of the electronic blood pressure machine is close to the pressure of 70 mmHg or even exceeds the pressure of 70 mmHg, the turning point T of the pulse wave measured by the electronic blood pressure machine _dic Gradually tends to be flat and close to a curve, and the deformed pulse wave is not suitable for calculating the Cardiac Output (CO), and when the pressure of the inflating tourniquet is lower than 55 mmHg, the phase is changedThe feature points of the off-going pulse wave may disappear or be not obvious, increasing the error after calculation.

(S02) measuring blood pressure: in the preferred embodiment, as shown in fig. 2 and 3, after the step of measuring the pulse wave by the measuring platform X, the electronic sphygmomanometer maintains the pressure of the tourniquet, i.e. maintains the pressure of 65 mm hg and continues to inflate the tourniquet, and performs the step of measuring the blood pressure of the subject, and the systolic pressure and the diastolic pressure of the blood pressure of the subject are measured, as shown in the preferred embodiment, 106 mm hg and 68 mm hg respectively. In other preferred embodiments, the step of measuring the blood pressure may be performed before the step of measuring the pulse wave by the measuring platform, and the step of measuring the blood pressure may be performed successively to the step of measuring the pulse wave by the measuring platform or may be performed separately with a time interval; in contrast, the preferred embodiment of the present invention has the advantages of measuring the Cardiac Output (CO) in the same cycle of inflating and deflating the tourniquet, and maximally preventing the tourniquet pressure from affecting the elasticity of the blood vessel and distorting the pulse wave measured subsequently, but the steps of measuring the blood pressure and measuring the pulse wave by the measuring platform can have an accuracy of more than eighty percent.

(S03) measuring heartbeat: in the preferred embodiment, the Heart Rate (HR) of the subject is measured during the step of measuring blood pressure, and the measured value is 71 counts/min. In other preferred embodiments, the heart rate may be measured during the step of measuring the pulse wave by the measuring platform, or at other times.

(S04) calculating stroke volume using the measurement parameters: using the waveform of the pulse wave and the peak T of the waveform _sys Maximum slope point T _inst Turning point T _dic Lowest point T _dia The parameters (2) are substituted into the heartbeat amount calculation formula to calculate the heartbeat amount (CO) by matching with the data of the systolic pressure and the diastolic pressure.

Please refer to the waveform of the pulse wave in fig. 3, which has the abscissa as unit time and the ordinate as pressure receivingData normalization is carried out on data of 106 mmHg of the systolic pressure and 68 mmHg of the diastolic pressure, the origin 0 second of the abscissa is the starting point of the pulse wave, and the coordinates of each characteristic point of the processed waveform are as follows: highest point T _sys (P _sys ,t _sys ) Is (0.144, 106), maximum slope point T _inst (P _inst ,t _inst ) Is (0.272, 96), turning point T _dic (P _dic ,t _dic ) Is (0.344, 89), lowest point T _dia (P _dia ,t _dia ) To (0.800, 68), the above parameters and data are substituted into the stroke volume calculation formula and calculation process as follows:

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as shown in equation 1, the Stroke Volume (SV) is equal to the area A under the systolic waveform divided by the reciprocal Z of the instantaneous acceleration of the vessel cross-section, A in the preferred embodiment is 10.1256; as shown in the formula 4, the time constant τ is the constant of the pulse wave in the diastolic period, the waveform of the pulse wave in the diastolic period is obtained by a curve approximation method to obtain a value, τ of the preferred embodiment is 0.20671, C is Arterial compliance (Arterial compliance), which is the volume change caused by the change of the unit pressure, and the buffering capacity of the Arterial blood vessel is reflected by the control measurement method or the model estimation method, and since the C values of healthy people in the electronic blood pressure meter of the same pressure pulse band and the measurement platform X of the same pressure are similar, the value is set as a constant, for example, the C value of the preferred embodiment is 0.20671, the value of tau is different for each pulse waveform, R is the Total peripheral vascular resistance (Total peripheral vascular resistance), and R is 6.36157 x 10 in the preferred embodiment by substituting tau and C into equation 4 ^-4 。

Substituting the coordinate parameters of the characteristic points into formula 3, calculating to obtain a dP of 277.25, wherein the calculation formula is as follows:

substituting the data for A, R and dP into equation 2 gives a stroke volume SV (ml) of 57.41, calculated as:

multiplying the Stroke Volume (SV) by the Heart Rate (HR) gives the subject a Cardiac Output (CO) of 4.08 liters (L), calculated as 57.41 × 71/1000.

In addition to the above preferred embodiment, the heart rate (SV) and the Cardiac Output (CO) are calculated by using the waveform parameter of one pulse wave, and the heart rate (SV) and the Cardiac Output (CO) can be calculated by using the waveform parameters of two or more pulse waves, and then the calculated average value is taken to improve the accuracy of the calculated heart rate (SV) and the calculated Cardiac Output (CO).

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (7)

1. A method for measuring a hemodynamic platform, the method comprising:

the measuring platform measures pulse waves: inflating a pulse pressing belt of an electronic sphygmomanometer to a measuring platform with the pressure of 55-70 mm Hg, keeping the pressure on the measuring platform for a set time by fixing the pressure, measuring pulse waves of a person to be measured, and capturing at least one pulse wave from a plurality of measured pulse waves, wherein the waveform of each pulse wave has characteristic points such as a highest point, a maximum slope point, a turning point, a lowest point and the like according to a time sequence;

measuring blood pressure: measuring the systolic pressure and diastolic pressure of the blood pressure of the person to be measured; and

calculating stroke volume using the measurement parameters: the heart stroke volume is calculated by matching the waveform of each pulse wave and the parameters of each characteristic point of the waveform with the data of systolic pressure and diastolic pressure.

2. The method of claim 1, wherein after the step of measuring the pulse wave by the measuring platform, the electronic sphygmomanometer keeps the pressure of the tourniquet to continue to inflate the tourniquet, so as to perform the step of measuring the blood pressure of the subject.

3. The method of claim 1 or 2, further comprising a step of measuring the heart rate of the subject, and multiplying the heart rate by the heart stroke volume in the step of calculating the heart stroke volume using the measurement parameter to obtain the cardiac output of the subject.

4. The method of claim 3, wherein the Stroke Volume (SV) is calculated according to the following formula:

wherein the highest point T _sys (P _sys ,t _sys ) Maximum slope point T _inst (P _inst ,t _inst ) Turning point T _dic (P _dic ,t _dic ) Lowest point T _dia (P _dia ,t _dia )。

5. The method of claim 1, wherein the step of measuring the blood pressure is performed before the step of measuring the pulse wave by the measuring platform, and the step of measuring the pulse wave by the measuring platform is performed after the step of measuring the blood pressure is completed.

6. The method of claim 5, further comprising a step of measuring the heart rate of the subject, and in the step of calculating the heart rate using the measurement parameters, the step of multiplying the heart rate by the heart rate to obtain the cardiac output of the subject.

7. The method of claim 6, wherein the Stroke Volume (SV) is calculated according to the following formula:

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wherein the highest point T _sys (P _sys ,t _sys ) Maximum slope point T _inst (P _inst ,t _inst ) Turning point T _dic (P _dic ,t _dic ) Lowest point T _dia (P _dia ,t _dia )。

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