CN114403827A - Continuous blood pressure measuring method - Google Patents

Abstract

The invention discloses a continuous blood pressure measuring method, which mainly relates to the field of blood pressure measurement; the method comprises the following steps: s1, the testee tightly attaches the electrode A provided with the photoelectric sensor to one of the earlobes, meanwhile, the index finger and the thumb of the right hand pinch the other electrode B provided with the photoelectric sensor, the electrodes A and B form a human body loop, and an electrocardiogram signal is obtained through the electrocardiogram detection module; s2, connecting the two groups of photoelectric sensors with a volume pulse wave pattern detection module, and respectively acquiring pulse wave patterns of the ear lobe and the tail end of the thumb; s3, calculating the time PWTT1 and PWTT2 of pulse wave propagation reaching the end of the ear lobe and the thumb and the heart rate period T by the analysis processing module according to the electrocardiogram signal of the step S1 and the two pulse wave maps of the step S2, and calculating the blood pressure value through a preset blood pressure model; the invention can effectively eliminate other interference factors such as human body, environment and the like, has more accurate measurement, reduces the system measurement noise and simplifies the measurement steps.

Description

Continuous blood pressure measuring method

Technical Field

The invention relates to the field of blood pressure measurement, in particular to a continuous blood pressure measurement method.

Background

At present, among the existing methods for measuring blood pressure, a non-invasive blood pressure detection method is popular among people, a pulse wave conduction method for measuring blood pressure is one of the common non-invasive blood pressure detection methods, and pulse wave measurement is commonly carried out on an earlobe or the tail end of a finger, because the earlobe and the tail end of the finger have rich capillary vessels, the pulse wave waveform is good, and the measurement is more accurate. The measurement of an Electrocardiogram (ECG) signal requires at least two electrodes attached to a far away position of a human body (generally, one electrode for each of a right hand and a left foot or one electrode for each of a left hand and a right hand), but the conventional method for measuring blood pressure often has the problem of low measurement accuracy, mainly because although the blood pressure and the pulse wave conduction velocity time are in a positive correlation relationship, the time for conducting the pulse wave to a certain reference base point (measurement point) is influenced by other factors, such as heart rate, posture of a subject, the degree of softening and hardening of blood vessels, blood vessel distribution and the like, and the factors often have very many individual differences, thereby causing errors.

Disclosure of Invention

The invention aims to solve the problems in the prior art, and provides a blood pressure continuous measurement method which can effectively eliminate other interference factors such as human bodies, environments (such as temperature and the like), is more accurate in measurement, reduces system measurement noise and simplifies measurement steps.

In order to achieve the purpose, the invention is realized by the following technical scheme:

a method for continuously measuring blood pressure, comprising the steps of:

s1, a testee tightly attaches an electrode A with a photoelectric sensor in the center to one of earlobes, simultaneously, the index finger and the thumb of the right hand pinch the other electrode B with the photoelectric sensor, the electrode A and the electrode B form a human body loop, and an Electrocardiogram (ECG) signal is obtained through an electrocardiogram detection module;

s2, connecting the two groups of photoelectric sensors with a volume pulse wave pattern detection module, and respectively acquiring pulse wave patterns of the ear lobe and the tail end of the thumb;

and S3, calculating the time PWTT1 and PWTT2 of pulse wave propagation reaching the end of the ear lobe and the thumb and the heart rate period T by the analysis processing module according to the Electrocardiogram (ECG) signal of the step S1 and the two groups of pulse wave maps of the step S2, and calculating the blood pressure value through a preset blood pressure model.

Preferably, the blood pressure model in step S3 is:

SBP＝a1×(PWTT1-PWTT2)+b1-c1/T；

DBP＝a2×(PWTT1-PWTT2)+b2-c2/T；

wherein SBP is systolic pressure and DBP is diastolic pressure;

PWTT1 is the time of pulse wave propagation reaching the ear lobe, PWTT2 is the time of pulse wave propagation reaching the end of the thumb, T is the heart rate period, and the units of PWTT1, PWTT2 and T are ms;

a1, a2, b1, b2, c1, c2 are fitting constants, and are parametrically calibrated by comparing blood pressure with standard sphygmomanometer measurements.

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

the invention uses the difference of the pulse wave propagation time of the ear lobe and the tail end of the finger and the current heart rate value to calculate the blood pressure, instead of singly using a measuring point (such as the tail end of the finger) as a reference point for calculating the blood pressure, thereby effectively eliminating other interference factors such as human body, environment (such as temperature and the like) and the like, and having more accurate measurement. And the ECG signal is measured through a human body current loop formed by the ear lobe and the tail end of the finger, so that the measuring device is easier to integrate and miniaturize, the system measuring noise is reduced, and the measuring step is simplified.

Drawings

FIG. 1 is a system schematic of the present invention;

figure 2 is a graph of blood pressure measurements versus fitted blood pressure for a first subject.

Detailed Description

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and these equivalents also fall within the scope of the present application.

Example 1: the invention relates to a blood pressure continuous measurement method, which comprises the following steps:

s1, a testee tightly attaches an electrode A with a photoelectric sensor in the center to one of two earlobes, and simultaneously, the index finger and the thumb of the right hand pinch the other electrode B with the photoelectric sensor, the electrode A and the electrode B form a human body loop, and an Electrocardiogram (ECG) signal is obtained through an electrocardiogram detection module;

s2, connecting the two groups of photoelectric sensors with a volume pulse wave pattern detection module, and respectively acquiring pulse wave patterns of the ear lobe and the tail end of the thumb;

and S3, calculating the time PWTT1 and PWTT2 of pulse wave propagation reaching the end of the ear lobe and the thumb and the heart rate period T by the analysis processing module according to the Electrocardiogram (ECG) signal of the step S1 and the two groups of pulse wave maps of the step S2, and calculating the blood pressure value through a preset blood pressure model.

The blood pressure model is as follows:

SBP＝a1×(PWTT1-PWTT2)+b1-c1/T；

DBP＝a2×(PWTT1-PWTT2)+b2-c2/T；

wherein SBP is systolic pressure and DBP is diastolic pressure;

PWTT1 is the time of pulse wave propagation reaching the ear lobe, PWTT2 is the time of pulse wave propagation reaching the end of the thumb, T is the heart rate period, and the units of PWTT1, PWTT2 and T are ms;

a1, a2, b1, b2, c1, c2 are fitting constants, and are parametrically calibrated by comparing blood pressure with standard sphygmomanometer measurements.

Example 2: in the experiment, 5 healthy testees are selected as a training set, the blood pressure measured by the method is compared with the blood pressure measured by an ohm dragon HEM-7051 type sphygmomanometer, and the measured data of the 5 testees are shown in the following table.

Test subject No. 1, male, age 35

Test subject No. 2, male, age 67

Test subject No. 3, female, age 17

Test subject No. 4, female, age 48

Test subject No. 5, female, age 72

As shown in the attached figure 2, the data of the first tested person are used as analysis, the maximum error of systolic blood pressure obtained by fitting the pulse wave time difference and the heart rate is 4.0mmHg, the calculated standard deviation is 2.3mmHg, the maximum error of diastolic blood pressure is-4.5 mmHg, the calculated standard deviation is 2.7mmHg, and the requirements that the standard deviation recommended by AAMI is lower than 8mmHg are met.

The test data show that the PWTT time difference value and the heart rate are greatly related to the blood pressure, and a mathematical model of the blood pressure-pulse wave conduction parameter can be established for continuously measuring the blood pressure. By way of comparison, if only PWTT1 and PWTT2 were used, a simple linear fit model was used and the calculated blood pressure errors were compared as shown in the following table.

Physical quantities used	PWTT1	PWTT2	PWTT time difference and heart rate
				Error of systolic pressure mmHg	7.2	5.6	4.0
Diastolic error mmHg	11.7	8.3	-4.5

It can be seen that the calculation of blood pressure using PWTT time difference and heart rate is more accurate than the blood pressure obtained using a single measurement base point.

Claims (2)

1. A method for continuously measuring blood pressure, comprising the steps of:

s1, a testee tightly attaches an electrode A with a photoelectric sensor in the center to one of earlobes, simultaneously, the index finger and the thumb of the right hand pinch the other electrode B with the photoelectric sensor, the electrode A and the electrode B form a human body loop, and an Electrocardiogram (ECG) signal is obtained through an electrocardiogram detection module;

s2, connecting the two groups of photoelectric sensors with a volume pulse wave pattern detection module, and respectively acquiring pulse wave patterns of the ear lobe and the tail end of the thumb;

and S3, calculating the time PWTT1 and PWTT2 of pulse wave propagation reaching the end of the ear lobe and the thumb and the heart rate period T by the analysis processing module according to the electrocardiogram signal of the step S1 and the two pulse wave maps of the step S2, and calculating the blood pressure value through a preset blood pressure model.

2. The method for continuously measuring blood pressure according to claim 1, wherein the blood pressure model in step S3 is:

SBP＝a1×(PWTT1-PWTT2)+b1-c1/T；

DBP＝a2×(PWTT1-PWTT2)+b2-c2/T；

wherein SBP is systolic pressure and DBP is diastolic pressure;

PWTT1 is the time of pulse wave propagation reaching the ear lobe, PWTT2 is the time of pulse wave propagation reaching the end of the thumb, T is the heart rate period, and the units of PWTT1, PWTT2 and T are ms;

a1, a2, b1, b2, c1, c2 are fitting constants, and are parametrically calibrated by comparing blood pressure with standard sphygmomanometer measurements.

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