CN112022128A - Medical equipment and PTT-based noninvasive blood pressure measurement method and device thereof - Google Patents

Medical equipment and PTT-based noninvasive blood pressure measurement method and device thereof Download PDF

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Publication number
CN112022128A
CN112022128A CN201910482921.9A CN201910482921A CN112022128A CN 112022128 A CN112022128 A CN 112022128A CN 201910482921 A CN201910482921 A CN 201910482921A CN 112022128 A CN112022128 A CN 112022128A
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ptt
value
pressure
blood pressure
cuff
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朱增友
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Edan Instruments Inc
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Edan Instruments Inc
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
    • A61B5/021—Measuring pressure in heart or blood vessels
    • A61B5/02108—Measuring pressure in heart or blood vessels from analysis of pulse wave characteristics
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
    • A61B5/021—Measuring pressure in heart or blood vessels
    • A61B5/022—Measuring pressure in heart or blood vessels by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
    • A61B5/0225—Measuring pressure in heart or blood vessels by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers the pressure being controlled by electric signals, e.g. derived from Korotkoff sounds
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
    • A61B5/1455—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters
    • A61B5/14551—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters for measuring blood gases
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/72—Signal processing specially adapted for physiological signals or for diagnostic purposes
    • A61B5/7203—Signal processing specially adapted for physiological signals or for diagnostic purposes for noise prevention, reduction or removal
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/72—Signal processing specially adapted for physiological signals or for diagnostic purposes
    • A61B5/7235—Details of waveform analysis
    • A61B5/725—Details of waveform analysis using specific filters therefor, e.g. Kalman or adaptive filters
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B2560/00—Constructional details of operational features of apparatus; Accessories for medical measuring apparatus
    • A61B2560/02—Operational features
    • A61B2560/0223—Operational features of calibration, e.g. protocols for calibrating sensors

Abstract

The invention discloses a medical device and a PTT-based noninvasive blood pressure measuring method and a PTT-based noninvasive blood pressure measuring device thereof, wherein the method comprises the following steps: acquiring a first PTT characteristic value when the cuff pressure is 0 mmHg; controlling the cuff pressure to a target pressure; performing step pressure relief on the cuff to obtain a second PTT characteristic value of the cuff under different step pressures of two or more than two steps, wherein the second PTT characteristic value is not 0 mmHg; and acquiring the blood pressure value of the detected object according to the first PTT characteristic value and two or more second PTT characteristic values. According to the method, in the process of measuring the blood pressure of the detected object, the first PTT characteristic value and the two or more second PTT characteristic values are obtained, so that the blood pressure value of the detected object can be obtained, the operation is simple, the implementation is easy, the reliability is high, no special requirement is required for the measurement environment, and the method can be suitable for different clinical environments.

Description

Medical equipment and PTT-based noninvasive blood pressure measurement method and device thereof
Technical Field
The invention relates to the technical field of blood pressure measurement, in particular to a medical device and a PTT-based noninvasive blood pressure measurement method and device thereof.
Background
When blood pressure value measurement is carried out, non-invasive measurement is a method which is widely applied at present, and most common methods are an auscultation method and an oscillography; they have in common: it is necessary to bind the cuff to the arm of the patient and indirectly obtain the blood pressure of the subject by pressurizing and depressurizing the cuff. What is different, the auscultatory method is that the blood pressure value is obtained by detecting the change of sound, and can be generally operated by professional medical staff; the oscillography is to indirectly obtain the blood pressure of a subject by detecting pulse wave characteristics under different cuff pressures, can be automatically completed by a control unit, and is adopted by most of current monitors. The noninvasive method has the characteristics of no wound and simple operation, and is widely applied in clinic.
However, when the non-invasive method is used for measuring the blood pressure, the cuff needs to be inflated and deflated, so that the arms of the subject are pressed, the discomfort is caused, and the rest of the subject is influenced if the blood pressure is measured frequently, especially at night; and because each time a measurement result is obtained, at least tens of seconds are needed, the blood pressure of each heartbeat cannot be obtained; some special patients in clinic need to detect the blood pressure of each heart beat to find the blood pressure variation as soon as possible and treat the blood pressure variation, and the measurement by the cuff method cannot meet the requirement in the case.
At present, some methods capable of realizing continuous blood pressure monitoring under a non-invasive condition, namely a non-invasive continuous blood pressure monitoring method based on pulse transmission time (PTT for short), have been developed in succession. Based on a K-M equation, namely the finding that the transmission speed of the pulse wave has correlation with the transmural pressure of the blood vessel, the arterial blood pressure corresponding to each heart beat can be calculated by monitoring the transmission speed (or transmission time) of the pulse wave corresponding to each heart beat and according to the established calibration equation reflecting the relationship between the pulse propagation time and the arterial blood pressure, and continuous arterial blood pressure can be obtained without cuff pressurization.
However, when continuous arterial blood pressure is obtained by using the pulse wave transmission time, the operation is complicated and the obtained blood pressure value of the detected object has a certain error.
Disclosure of Invention
The embodiment of the invention provides a medical device and a PTT-based noninvasive blood pressure measuring method and device thereof, solves the technical problems that the operation is complex and the obtained blood pressure value of a detected object has certain error when the blood pressure is measured in the prior art, and achieves the technical effects of simple operation, easy implementation and high reliability when the blood pressure is measured.
Therefore, the first objective of the present invention is to provide a PTT-based noninvasive blood pressure measurement method, which is adaptable to different clinical environments, simple in operation, easy to implement, and highly reliable.
The second purpose of the invention is to provide a PTT-based noninvasive blood pressure measuring device.
A third object of the invention is to propose a medical device.
A fourth object of the invention is to propose a computer-readable storage medium.
In order to achieve the above object, an embodiment of a first aspect of the present invention provides a PTT-based noninvasive blood pressure measurement method, including:
acquiring a first PTT characteristic value when the cuff pressure is 0 mmHg;
controlling the cuff pressure to a target pressure;
performing step pressure relief on the cuff to obtain a second PTT characteristic value of the cuff under different step pressures of two or more than two steps, wherein the second PTT characteristic value is not 0 mmHg;
and acquiring the blood pressure value of the detected object according to the first PTT characteristic value and two or more second PTT characteristic values.
According to one embodiment of the invention, the step pressure relief of the cuff to obtain the second PTT characteristic value of the cuff at different 0mmHg under two or more different step pressures comprises:
when the pressure is released to one step pressure each time, at least one PTT value of the tested object under the step pressure is obtained;
and acquiring a second PTT characteristic value under the step pressure according to the at least one PTT value.
According to an embodiment of the present invention, before the controlling the cuff pressure to the target pressure, further comprises:
acquiring a reference blood pressure value of the measured object, wherein the reference blood pressure value at least comprises diastolic pressure and systolic pressure;
determining the average pressure of the measured object according to the reference blood pressure value;
and determining the target pressure according to the average pressure.
According to an embodiment of the present invention, further comprising:
judging whether the current step pressure is greater than a preset step pressure threshold value or not;
if the current step pressure is larger than the preset step pressure threshold value, continuing to perform step pressure relief;
and if the current step pressure is less than or equal to the preset step pressure threshold, controlling the cuff pressure to be decompressed to an initial state.
According to an embodiment of the present invention, before the obtaining the second PTT characteristic value at the step pressure, the method further includes:
detecting pulse waves in real time in the process of releasing pressure from the previous step to the current step each time;
judging whether a first peak value appears in the trend formed by the pulse waves, wherein the first peak value is respectively a preset multiple of the peak values on two adjacent sides of the first peak value;
and when the first peak value of the pulse wave is judged to appear, a second PTT characteristic value corresponding to the current step pressure is obtained.
According to an embodiment of the present invention, further comprising:
after the pulse wave is judged to have the first peak value, judging whether the diastolic pressure of the detected object is detected or not;
if the diastolic pressure of the detected object is detected, acquiring the reference blood pressure value;
and controlling the pressure relief of the cuff to an initial state.
According to an embodiment of the present invention, the obtaining the blood pressure value of the detected object according to the first PTT characteristic value and two or more second PTT characteristic values includes:
acquiring the width of the cuff, the distance between specified points of the detected object and a reference blood pressure value of the detected object;
acquiring calibration parameters for calibrating blood pressure according to the first PTT characteristic value, the second PTT characteristic value and cuff pressure values corresponding to the second PTT characteristic value, the width, the distance and the reference blood pressure value;
and calibrating the reference blood pressure value according to the calibration parameter and the real-time measured PTT value to obtain a calibrated blood pressure value of the detected object.
According to an embodiment of the present invention, the acquiring a calibration parameter for calibrating a blood pressure according to the cuff pressure value corresponding to the first PTT characteristic value, the second PTT characteristic value, and the second PTT characteristic value, the width, the distance, and the reference blood pressure value includes:
acquiring a first calibration parameter for correcting the blood pressure according to the first PTT characteristic value, the second PTT characteristic value and the cuff pressure value corresponding to the second PTT characteristic value, the width and the distance;
and acquiring a second calibration parameter for correcting the blood pressure according to the first PTT characteristic value, the first calibration parameter and the reference blood pressure value.
According to an embodiment of the present invention, the specific formula for obtaining the first calibration parameter for correcting the blood pressure is as follows:
K＝(ln(PTTi-(L2-L1)/L2*PTT0)-ln(PTTj-(L2-L1)/L2*PTT0))/(Pi–Pj)
where K is the first calibration parameter, PTT0Is a first PTT feature value, PTTi、PTTjIs the second PTT feature value, Pi、PjAre respectively PTTi、PTTjCorresponding cuff pressure value, L1Width of the cuff, L2The distance between points is specified for the detected object.
According to an embodiment of the present invention, the specific formula for obtaining the second calibration parameter for correcting the blood pressure is as follows:
B＝PTT0/exp(-K*BP0)
wherein B is a second calibration parameter, BP0Is a reference blood pressure value.
According to an embodiment of the present invention, the specific formula for calibrating the reference blood pressure value according to the calibration parameter and the real-time measured PTT value is as follows:
BP＝(ln(B)–ln(PTT))/K
in the formula, BP is a blood pressure value after calibration, and PTT is a PTT value measured in real time.
According to an embodiment of the present invention, further comprising:
when the second PTT characteristic values are more than two, combining the second PTT characteristic values in pairs;
inputting the second PTT characteristic value and the corresponding cuff pressure value in each combination into a calculation formula of the first calibration parameter to determine a candidate first calibration parameter;
determining the final first calibration parameter according to the candidate first calibration parameters of all combinations.
According to an embodiment of the present invention, further comprising:
acquiring the relative height between the appointed points of the detected object;
and if the relative height is larger than a preset value, calibrating the real-time measured PTT value.
According to an embodiment of the present invention, the specific formula for calibrating the real-time measured PTT value is:
PTTx＝(L*ρ*g*M)/(1-exp(-M*ρ*g*h)*PTTy)
wherein, PTTxFor the calibrated PTT value, L is the distance between the designated points of the detected object, ρ is the blood density, g is the gravity acceleration, M is a constant, h is the relative height, and PTT isyIs a real-time measured PTT value.
According to the noninvasive blood pressure measuring method based on the PTT, provided by the embodiment of the first aspect of the invention, after the first PTT characteristic value of the cuff pressure of 0mmHg is obtained, the cuff pressure is controlled to the target pressure; then, the cuff is subjected to step pressure relief to obtain a second PTT characteristic value of the cuff under different step pressures of two or more than two different step pressures, wherein the second PTT characteristic value is not 0 mmHg; and further, acquiring the blood pressure value of the detected object according to the first PTT characteristic value and the plurality of second PTT characteristic values. According to the method, in the process of measuring the blood pressure of the detected object, the first PTT characteristic value and the two or more second PTT characteristic values are obtained, so that the blood pressure value of the detected object can be obtained, the operation is simple, the implementation is easy, the reliability is high, no special requirement is required for the measurement environment, and the method can be suitable for different clinical environments.
In a second aspect, an embodiment of the present invention provides a PTT-based noninvasive blood pressure measuring apparatus, including:
the first acquisition module is used for acquiring a first PTT characteristic value when the cuff pressure is 0 mmHg;
a control module for controlling the cuff pressure to a target pressure;
the second acquisition module is used for carrying out step pressure relief on the cuff to acquire a second PTT characteristic value which is not 0mmHg under two or more different step pressures;
and the processing module is used for acquiring the blood pressure value of the detected object according to the first PTT characteristic value and two or more second PTT characteristic values.
According to an embodiment of the present invention, the second obtaining module is further configured to:
when the pressure is released to one step pressure each time, at least one PTT value of the tested object under the step pressure is obtained;
and acquiring a second PTT characteristic value under the step pressure according to the at least one PTT value.
According to an embodiment of the present invention, the second obtaining module is further configured to:
acquiring a reference blood pressure value of the measured object, wherein the reference blood pressure value at least comprises diastolic pressure and systolic pressure;
determining the average pressure of the measured object according to the reference blood pressure value;
and determining the target pressure according to the average pressure.
According to an embodiment of the present invention, the second obtaining module is further configured to:
judging whether the current step pressure is greater than a preset step pressure threshold value or not;
if the current step pressure is larger than the preset step pressure threshold value, continuing to perform step pressure relief;
and if the current step pressure is less than or equal to the preset step pressure threshold, controlling the cuff pressure to be decompressed to an initial state.
According to an embodiment of the present invention, the second obtaining module is further configured to:
detecting pulse waves in real time in the process of releasing pressure from the previous step to the current step each time;
judging whether a first peak value appears in the trend formed by the pulse waves, wherein the first peak value is respectively a preset multiple of the peak values on two adjacent sides of the first peak value;
and when the first peak value of the pulse wave is judged to appear, a second PTT characteristic value corresponding to the current step pressure is obtained.
According to an embodiment of the present invention, the second obtaining module is further configured to:
after the pulse wave is judged to have the first peak value, judging whether the diastolic pressure of the detected object is detected or not;
if the diastolic pressure of the detected object is detected, acquiring the reference blood pressure value;
and controlling the pressure relief of the cuff to an initial state.
According to an embodiment of the present invention, the processing module is further configured to: acquiring the width of the cuff, the distance between specified points of the detected object and a reference blood pressure value of the detected object;
acquiring calibration parameters for calibrating blood pressure according to the first PTT characteristic value, the second PTT characteristic value and cuff pressure values corresponding to the second PTT characteristic value, the width, the distance and the reference blood pressure value;
and calibrating the reference blood pressure value according to the calibration parameter and the real-time measured PTT value to obtain a calibrated blood pressure value of the detected object. According to an embodiment of the present invention, the processing module is further configured to:
acquiring a first calibration parameter for correcting the blood pressure according to the first PTT characteristic value, the second PTT characteristic value and the cuff pressure value corresponding to the second PTT characteristic value, the width and the distance;
and acquiring a second calibration parameter for correcting the blood pressure according to the first PTT characteristic value, the first calibration parameter and the reference blood pressure value.
According to an embodiment of the present invention, the specific formula of the processing module for obtaining the first calibration parameter for correcting the blood pressure is as follows:
K＝(ln(PTTi-(L2-L1)/L2*PTT0)-ln(PTTj-(L2-L1)/L2*PTT0))/(Pi–Pj)
where K is the first calibration parameter, PTT0Is a first PTT feature value, PTTi、PTTjIs the second PTT feature value, Pi、PjAre respectively PTTi、PTTjCorresponding cuff pressure value, L1Width of the cuff, L2The distance between points is specified for the detected object.
According to an embodiment of the present invention, the specific formula for the processing module to obtain the second calibration parameter for correcting the blood pressure is as follows:
B＝PTT0/exp(-K*BP0)
wherein B is a second calibration parameter, BP0Is a reference blood pressure value.
According to an embodiment of the present invention, the specific formula for calibrating the reference blood pressure value by the processing module according to the calibration parameter and the real-time measured PTT value is as follows:
BP＝(ln(B)–ln(PTT))/K
in the formula, BP is a calibrated blood pressure value, and PTT is a PTT value measured in real time.
According to an embodiment of the present invention, the processing module is further configured to:
when the second PTT characteristic values are more than two, combining the second PTT characteristic values in pairs;
inputting the second PTT characteristic value and the corresponding cuff pressure value in each combination into a calculation formula of the first calibration parameter to determine a candidate first calibration parameter;
determining the final first calibration parameter according to the candidate first calibration parameters of all combinations.
According to an embodiment of the present invention, the processing module is further configured to:
acquiring the relative height between the appointed points of the detected object;
and if the relative height is larger than a preset value, calibrating the real-time measured PTT value.
According to an embodiment of the present invention, the specific formula for the processing module to calibrate the real-time measured PTT value is as follows:
PTTx＝(L*ρ*g*M)/(1-exp(-M*ρ*g*h)*PTTy)
wherein, PTTxFor the calibrated PTT value, L is the distance between the designated points of the detected object, ρ is the blood density, g is the gravity acceleration, M is a constant, h is the relative height, and PTT isyIs a real-time measured PTT value.
According to the noninvasive blood pressure measuring device based on PTT provided by the embodiment of the second aspect of the invention, after the first acquisition module acquires the first PTT characteristic value when the cuff pressure is 0mmHg, the control module controls the cuff pressure to the target pressure; then, a second acquisition module performs step pressure relief on the cuff to acquire a second PTT characteristic value of the cuff under different step pressures of not 0 mmHg; further, the processing module obtains the blood pressure value of the detected object according to the first PTT characteristic value and the plurality of second PTT characteristic values. The device obtains the first PTT characteristic value and two or more than two second PTT characteristic values in the process of measuring the blood pressure of the detected object, so that the operation for obtaining the blood pressure value of the detected object is simple, the implementation is easy, the reliability is high, and the device has no special requirements on the measurement environment and can adapt to different clinical environments.
In a third aspect, embodiments of the present invention provide a medical device, including a memory, a processor;
wherein the processor executes a program corresponding to the executable program code by reading the executable program code stored in the memory for implementing the PTT-based noninvasive blood pressure measurement method of the first aspect.
A fourth aspect of the present invention provides a computer-readable storage medium, on which a computer program is stored, which when executed by a processor implements the PTT-based noninvasive blood pressure measuring method of the first aspect.
Drawings
FIG. 1 is a schematic flow chart of a PTT-based non-invasive blood pressure measurement method according to an embodiment of the present disclosure;
FIG. 2 is a first sequence of PTT values obtained by the PTT-based non-invasive blood pressure measurement method of FIG. 1;
FIG. 3 is a pulse wave trend graph of the PTT-based non-invasive blood pressure measurement method of FIG. 1;
FIG. 4 is a schematic diagram of the steps of obtaining the blood pressure value of the detected object in the non-invasive PTT-based blood pressure measurement method according to the embodiment of the disclosure;
FIG. 5 is a schematic diagram of a step of calibrating a blood pressure value of a subject in a PTT-based noninvasive blood pressure measurement method according to an embodiment of the disclosure;
FIG. 6 is a control flow diagram of a PTT-based non-invasive blood pressure measurement method according to an embodiment of the disclosure;
FIG. 7 is a control flow diagram of a PTT-based non-invasive blood pressure measurement method according to another embodiment of the disclosure;
FIG. 8 is a flow chart of a method for obtaining a PTT value according to an embodiment of the disclosure;
FIG. 9 is a schematic structural diagram of a PTT-based non-invasive blood pressure measurement device according to an embodiment of the present disclosure;
FIG. 10 is a schematic diagram of a medical device according to an embodiment of the present disclosure.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
The medical device and the PTT-based noninvasive blood pressure measurement method and device thereof according to the embodiment of the invention are described below with reference to the accompanying drawings.
Fig. 1 is a flow chart of a PTT-based noninvasive blood pressure measurement method according to an embodiment of the disclosure.
As shown in fig. 1, the PTT-based noninvasive blood pressure measurement method provided in the embodiment of the present invention includes the following steps:
s101, acquiring a first PTT characteristic value when the cuff pressure is 0 mmHg.
It should be noted that the method provided by the embodiment of the present invention is mainly applied to medical equipment, such as a monitor, for non-invasive blood pressure measurement of the monitor, and the monitor can measure data including electrocardiographic data, respiration data, non-invasive blood pressure data, blood oxygen saturation data, pulse data, body temperature data, and the like. It should be understood that the method may also be applied to other devices based on non-invasive blood pressure measurements.
In the calibration process of the Noninvasive blood pressure measured by the monitor, a Noninvasive blood pressure (NIBP) measurement module in the monitor needs to obtain at least three pulse wave propagation time characteristic values (hereinafter referred to as PTT characteristic values), wherein at least one PTT value is a PTT characteristic value when the cuff pressure is 0 mmHg. For convenience of description, the PTT characteristic value at the cuff pressure of 0mmHg is referred to as a first PTT characteristic value, and the PTT characteristic values at the other cuff pressures are collectively referred to as a second PTT characteristic value.
In some embodiments, PTT values for a period of time T or for a certain number N, corresponding to non-concentric beats, may be collected before initiating the NIBP measurement module to measure blood pressure. Further, according to the PTT value, a PTT characteristic value (i.e., a first PTT characteristic value) at the pressure (i.e., 0mmHg) is calculated, and the first PTT characteristic value and a corresponding cuff pressure value thereof are stored.
Alternatively, in order to obtain a more accurate first PTT feature value, it is preferable to collect a plurality of first PTT values of different beats, where the collection time T is 10s to 15s and the collection number N > is 5 in this embodiment. When enough first PTT values at that pressure are collected, the first PTT characteristic value can be calculated.
When the first PTT characteristic value is calculated, the first PTT value sequence is sorted according to size, a plurality of data in the middle are taken for average calculation, or the value with the most frequency is selected for average calculation, or the data with obvious abnormality is removed, and then the rest data are taken for average calculation.
For example, as shown in fig. 2, the data with the first PTT value of 120 is obviously abnormal, so it can be culled; the remaining data are all normal, so the remaining data can be averaged, i.e. 80+78+80+82 to 80, to obtain a first PTT characteristic value of 80; alternatively, 80 may be directly selected as the first PTT characteristic value because 80 occurs a greater number of times.
In addition, for the purpose of measuring the accuracy of the result, after the first PTT characteristic value is obtained, a period of time is waited, the first PTT characteristic value is obtained once again, and the first PTT characteristic values obtained twice are averaged to obtain the required first PTT characteristic value.
And S102, controlling the cuff pressure to the target pressure.
Specifically, the NIBP measurement module may be activated to inflate the cuff until the cuff pressure reaches the target pressure.
S103, carrying out step pressure relief on the cuff, and obtaining a second PTT characteristic value of the cuff under different step pressures of not 0mmHg at two or more different step pressures.
Specifically, after the cuff pressure reaches the target pressure, the NIBP measurement module is started to perform step pressure relief on the cuff to obtain a second PTT characteristic value of the measured object under the current step pressure. And the second PTT characteristic value is at least two, namely, the cuff is decompressed at least twice.
Optionally, at least one PTT value of the measured object under the step pressure can be obtained each time the pressure is relieved to one step pressure; then, according to at least one PTT value, a second PTT characteristic value under step pressure is obtained, and the obtaining manner of the second PTT characteristic value can specifically refer to the manner of obtaining the first PTT characteristic value in step S101.
And S104, acquiring the blood pressure value of the detected object according to the first PTT characteristic value and two or more second PTT characteristic values.
Specifically, by acquiring the first PTT characteristic value and the two or more second PTT characteristic values, the blood pressure value of the detected object can be acquired according to the first PTT characteristic value and the two or more second PTT characteristic values.
As a possible implementation manner, the blood pressure value of the detected object may be obtained based on a mapping relationship between the first PTT characteristic value and the plurality of second PTT characteristic values and the blood pressure value of the detected object. Specifically, the mapping relationship between the first PTT characteristic value and the plurality of second PTT characteristic values and the blood pressure value of the detected object may be pre-constructed, and after the first PTT characteristic value and the plurality of second PTT characteristic values are obtained, the NIBP measurement module may obtain the blood pressure value of the detected object by querying the mapping relationship between these parameters.
In summary, according to the non-invasive blood pressure measurement method based on PTT provided in this embodiment, after the first PTT characteristic value is obtained when the cuff pressure is 0mmHg, the cuff pressure is controlled to the target pressure; then, the cuff is subjected to step pressure relief to obtain a second PTT characteristic value of the cuff under different step pressures of two or more than two different step pressures, wherein the second PTT characteristic value is not 0 mmHg; and further, acquiring the blood pressure value of the detected object according to the first PTT characteristic value and the plurality of second PTT characteristic values. According to the method, in the process of measuring the blood pressure of the detected object, the first PTT characteristic value and the two or more second PTT characteristic values are obtained, so that the blood pressure value of the detected object can be obtained, the operation is simple, the implementation is easy, the reliability is high, no special requirement is required for the measurement environment, and the method can be suitable for different clinical environments.
In some embodiments, the target pressure may be a preset pressure value of the system, or may be a manual input by a user or a system generates different pressure values according to different detected objects.
When the target pressure is a pressure preset by a system or a pressure value manually input by a user, the pressure of the cuff is subjected to step pressure relief, and the pulse wave information of the detected object is detected in real time and the envelope trend of the pulse wave information is judged in the process of pressure relief from the previous step to the current step each time. Specifically, it is determined whether a first peak appears in a trend formed by the pulse wave, where the first peak is a preset multiple of two adjacent peaks of the first peak, the multiple is preset, and in this embodiment, the preset multiple is 1.1. And when the pulse wave is judged to have the first peak value, acquiring a second PTT characteristic value corresponding to the current step pressure. For a specific process of obtaining the second PTT characteristic value, reference may be made to the above description of obtaining the first PTT characteristic value, and details are not repeated here.
As shown in fig. 3, when the cuff pressure is 105mmHg, the pulse wave forms a trend in which all the peaks between adjacent peaks do not differ by a predetermined multiple, such as 1.1 times, and thus the first peak does not appear; when the cuff pressure is 95mmHg, in the trend of the pulse wave formation, the peak value at the time Ta differs from the peak value on the left side by a preset multiple, such as 1.1 times, and also differs from the peak value on the right side by a preset multiple, such as 1.1 times, so that the first peak value appears at this time, and at this time, the second PTT characteristic value corresponding to 95mmHg is obtained, and the obtained second PTT characteristic value is stored.
In order to obtain the second PTT characteristic value smoothly, it is necessary to detect whether the PTT detection function on the monitor is turned on before obtaining the second PTT characteristic value. In the present embodiment, when the first peak in the pulse wave trend is detected, the PTT detection function is turned on. In addition, the first peak value may be an average pressure of the detected object, that is, when the average pressure of the detected object is detected, the second PTT characteristic value at the current pressure is obtained.
And stopping continuously detecting the PTT value after enough second PTT characteristic value and the cuff pressure value corresponding to the second PTT characteristic value are obtained. In this embodiment, whether to stop continuously detecting the PTT value is determined by determining whether the diastolic pressure of the detected object appears in the pulse wave trend. When the controller in the monitor detects the diastolic pressure of the detected object, the controller stops continuously detecting the PTT value and controls to measure the reference blood pressure value of the detected object. After the reference blood pressure value of the detected object is obtained, the cuff pressure is controlled to be deflated and decompressed to an initial state (namely 0 mmHg).
In this embodiment, when the target pressure is the preset pressure, the preset pressure needs to be applied to the arm of the detected object in the detection process. Due to the regulation in the current industry standard, when the cuff pressurization time exceeds a certain time, the cuff needs to be immediately decompressed, namely overtime protection; therefore, when the pulse rate of the detected object is low, the measurement time may last for a long time, and the long measurement time may trigger the timeout protection, which makes the blood pressure measurement work ineffective. Therefore, in order to effectively perform the blood pressure measurement, the target pressure in this embodiment may also generate different pressure values according to different detected objects, which will be described in detail below.
When the target pressure is different pressure values generated by the system according to different detected objects, the target pressure is determined according to a reference blood pressure value of the detected object obtained by preselection, wherein the reference blood pressure value at least comprises a Diastolic Blood Pressure (DBP) and a Systolic Blood Pressure (SBP). In this embodiment, the target pressure value is a difference between an average pressure (MAP) of the detected object and a constant, that is, the target pressure is (MAP-k) mmHg, where k is a positive integer; the average pressure can be calculated directly by an instrument, or can be calculated according to an empirical formula MAP 1/3 SBP +2/3 DBP.
It should be noted that the reference blood pressure value at this time can be input by the user or measured directly by the NIBP measurement module. When the NIBP measurement module is used to directly measure the reference blood pressure value of the subject, the first PTT characteristic value may be acquired before or after the first PTT characteristic value is acquired before the cuff is pressurized. In the embodiment, when an NIBP measurement module is used to directly measure the reference blood pressure value of the detected object, a first PTT characteristic value is obtained first when the cuff pressure is 0 mmHg; further, pressurizing the cuff to obtain a reference blood pressure value; after the reference blood pressure value is obtained, the cuff is deflated and decompressed, so that the cuff is restored to the initial state; further, the first PTT characteristic value when the cuff pressure is 0mmHg is acquired for the second time, and the first PTT characteristic values acquired twice are averaged to obtain an accurate first PTT characteristic value.
After the first PTT characteristic value is obtained, i.e., the cuff pressure is controlled to the target pressure (MAP-k) mmHg, in the present embodiment, the value of k is 5. Further, a second PTT characteristic value under the pressure is obtained, and the second PTT characteristic value and a pressure value corresponding to the second PTT characteristic value are stored. After the second PTT characteristic value corresponding to the target pressure (MAP-5) mmHg is obtained, the cuff pressure relief is controlled according to the preset step length, and the second PTT characteristic value corresponding to the pressure of each step is obtained. In the embodiment, the preset steps of MAP-Delta P, MAP-2 Delta P and MAP-3 Delta P … … are provided, wherein Delta P ranges from 5mmHg to 15 mmHg.
Detecting whether the current step pressure is greater than a preset step pressure threshold or not in the process of carrying out step pressure relief on the cuff, and if the current step pressure is greater than the preset step pressure threshold, continuing to carry out step pressure relief; and if the current step pressure is less than or equal to the preset step pressure threshold, controlling the pressure relief of the cuff to an initial state. In this embodiment, the preset step pressure threshold is 0.6 times the diastolic pressure. It should be understood that at least a second PTT characteristic value at two different pressures should be guaranteed to be obtained before the cuff is deflated.
In some embodiments, the blood pressure value of the detected subject may be obtained by the following steps, as shown in fig. 4, including:
s401, acquiring the width of the cuff, the distance between the designated points of the detected object and the reference blood pressure value of the detected object.
Specifically, parameters such as the length and the width of the cuff can be input through actual measurement, or the length and the width of the cuff can be pre-stored in the monitor by a manufacturer, or can be directly obtained from equipment parameters stored in the monitor, which can be specifically determined according to actual conditions.
The distance between the designated points of the detected object refers to the distance from the heart of the detected object to the finger in the present embodiment, specifically, the distance from the center of the heart of the detected object to the finger tip of the detected object, and the distance can be calculated according to the field measurement and input into the monitor.
The reference blood pressure value of the detected object can be directly measured by the monitor, or can be automatically inputted into the monitor by the user, as described in detail below.
S402, acquiring calibration parameters for calibrating the blood pressure according to the first PTT characteristic value, the second PTT characteristic value, the cuff pressure value corresponding to the second PTT characteristic value, the width, the distance and the reference blood pressure value.
Specifically, in this embodiment, there are two calibration parameters, where the first calibration parameter is calculated according to the cuff pressure value corresponding to the first PTT characteristic value, the second PTT characteristic value, and the second PTT characteristic value, as well as the cuff width and the distance between the specified points of the detected object; and the second calibration parameter is calculated according to the first PTT characteristic value, the first calibration parameter and the reference blood pressure value.
The specific formula of the first calibration parameter is as follows:
K＝(ln(PTTi-(L2-L1)/L2*PTT0)-ln(PTTj-(L2-L1)/L2*PTT0))/(Pi–Pj)
where K is the first calibration parameter, PTT0Is a first PTT feature value, PTTi、PTTjIs the second PTT feature value, Pi、PjAre respectively PTTi、PTTjCorresponding cuff pressure value, L1Width of the cuff, L2The distance between points is specified for the detected object.
The specific formula of the second calibration parameter is as follows:
B＝PTT0/exp(-K*BP0)
wherein B is a second calibration parameter, BP0Is a reference blood pressure value.
In some embodiments, the number of the obtained second PTT feature values may exceed two, and at this time, the second PTT feature values may be combined two by two; for each combination, inputting the second PTT characteristic value and the corresponding cuff pressure value in the combination into a calculation formula of the first calibration parameter, and determining a candidate first calibration parameter; further, a final first calibration parameter is determined based on the candidate first calibration parameters of all combinations.
When the final first calibration parameter is determined, sorting the candidate first calibration parameters according to the size relation, and selecting a plurality of intermediate data for averaging to obtain the final first calibration parameter; or determining a final first calibration parameter according to the frequency distribution; or eliminating the obviously abnormal values, and averaging the rest data to obtain the final first calibration parameter.
And S403, calibrating the reference blood pressure value according to the calibration parameters and the PTT value measured in real time to obtain the blood pressure value of the detected object.
Specifically, after a second calibration parameter is obtained, the monitor is controlled to obtain a real-time PTT value of the detected object; further, the reference blood pressure value is calibrated according to the calibration parameters and the PTT value measured in real time to obtain the blood pressure value of the detected object.
The specific formula for calibrating the reference blood pressure value is as follows:
BP＝(ln(B)–ln(PTT))/K
in the formula, BP is a blood pressure value after calibration, and PTT is a PTT value measured in real time.
It should be noted that BP is a calibrated blood pressure value, which may be one of SBP, DBP and MAP, and specifically depends on the reference blood pressure value in step S401.
It should be understood that the default in the above measurement procedure is: the detected object is in a lying posture, and the arm of the detected object is required to be flush with the heart position during measurement, so that the estimated blood pressure value (namely the blood pressure value after calibration) obtained by the measurement method can visually reflect the real blood pressure level of the detected object. However, when the arm of the subject cannot be kept at the same level as the heart (for example, when the subject moves, the arm naturally drops, or the arm lifts over the head, etc.), the estimated blood pressure value directly calculated by using the above calibration parameters cannot reflect the true blood pressure level of the subject, and therefore, the parameters need to be adjusted appropriately so that the calibrated blood pressure can reflect the true blood pressure level of the subject. In addition, when the blood pressure value of the detected object is obtained, the reference blood pressure of the detected object can be calibrated only by measuring the distance between the designated points of the detected object, no special requirement is required for whether the detected object needs to move, equivalent blood pressure transformation is not required, the operation is simple, the implementation is easy, the reliability is high, and the adaptability of the clinical environment is strong.
In some embodiments, the blood pressure value of the detected object measured by the above method may have an error when considering that the arm of the detected object may not always be kept flush with the heart during the actual measurement, for example, the patient lifts the arm during the measurement, or changes the sitting posture, the standing posture, and the like, which may change the vertical distance between the arm and the heart. Therefore, in order to avoid the occurrence of detection errors, the blood pressure value of the subject to be detected can be calibrated by the following steps. Specifically, as shown in fig. 5, the step includes:
s501, acquiring the relative height between the designated points of the detected object.
Specifically, an acceleration sensor may be added to the finger of the detected object to monitor whether the finger is deviated from the horizontal position of the heart, and the relative height h of the arm with respect to the position of the heart may be obtained according to the acceleration sensor and the known length of the arm, the distance from the heart to the shoulder, and the like (preferably, a three-axis acceleration sensor may obtain the moving direction and acceleration value of the arm in time, and obtain the moving state and moving distance of the arm by integration, thereby obtaining the relative height h of the arm with respect to the heart).
It should be noted that, in this embodiment, the distance between the designated points of the detected object refers to the relative height of the arm of the detected object with respect to the heart position thereof.
And S502, judging the size between the relative height and a preset value.
Specifically, if the relative height is greater than the preset value, step S503 is performed; otherwise, step S504 is executed.
S503, calibrating the PTT value measured in real time.
Specifically, when the relative height h is detected to be larger than a preset value, the PTT value measured in real time is calibrated, and the calibrated PTT value is substituted into the calibration formula, so that the reference blood pressure calibration value reflecting the detected object can be obtained when the arm deviates from the horizontal position of the heart.
Wherein, the specific formula of calibration is as follows:
PTTx＝(L*ρ*g*M)/(1-exp(-M*ρ*g*h)*PTTy)
in the formula, PTTxFor the calibrated PTT value, L is the distance between the designated points of the detected object, ρ is the blood density, g is the gravity acceleration, M is a constant, h is the relative height, and PTT isyIs a real-time measured PTT value.
And S504, stopping calibration.
Specifically, when the detected relative height h is smaller than or equal to the preset value, it indicates that the relative height is in the labeling range at this time, and the blood pressure value of the detected object does not need to be calibrated.
Fig. 6 is a control flow diagram of a PTT-based noninvasive blood pressure measurement method according to an embodiment of the disclosure. As shown in fig. 6, the method specifically includes the following steps:
s601, clearing the existing PTT sequence after starting detection;
s602, collecting T second PTT data, calculating characteristic value of a calculator, and calculating PTT0Storing PTT0And the current cuff pressure P0；
S603, starting an NIBP measuring module, and controlling a pump valve to inflate the cuff pressure to a target pressure;
s606, performing step pressure relief on the cuff pressure;
s605, detecting pulse wave information in real time;
s606, judging the pulse wave envelope trend;
s607, judging whether MAP is detected; if MAP is detected, steps S608 to S612 are performed; otherwise, go to step S616;
s608, starting PTT detection;
s609, clearing the PTT sequence to calculate a new PTT value;
s610, collecting a current step PTT value;
s611, calculating a PTT sequence characteristic value;
s612, storing the characteristic value and the current step pressure into a cache region, and executing a step S613;
s613, judging whether DBP is detected or not, and acquiring at least two second PTT characteristic values; if yes, executing steps S616 to S618; otherwise, returning to execute the step S606;
s616, calculating NIBP parameters to obtain SBP, DBP and MAP;
s615, after NIBP measurement is finished, opening a valve to deflate, and enabling the cuff pressure to be restored to the initial state;
s616, calculating a PTT calibration parameter K;
s617, calculating a PTT calibration parameter B;
and S618, setting the calibration mark as TRUE, obtaining the calibrated blood pressure value, and ending the measurement.
Fig. 7 is a control flow chart of a PTT-based noninvasive blood pressure measurement method according to another embodiment of the present disclosure. As shown in fig. 7, the method specifically includes the following steps:
s701, judging whether the reference blood pressure is measured by an NIBP measuring module; if so, executing steps S702 to S707; otherwise, executing steps S707 to S709;
s702, collecting the PTT value in T seconds, calculating the characteristic value, and recording the characteristic value as PTT0_1；
S703, starting an NIBP measuring module to measure the current blood pressure values (SBP, DBP and MAP);
s704, waiting for T2 seconds, and completely discharging the gas in the cuff;
s707, collecting PTT value in T seconds, calculating characteristic value, and calculating PTT value0_2；
S706, calculating the PTT0＝0.7*(PTT0_1+PTT0_2) To PTT0Current pressure P0Storing; and executing steps S710 to S720;
s707, receiving input reference blood pressure values (SBP, DBP and MAP);
s708, collecting the PTT value in T seconds, calculating the characteristic value, and calculating the characteristic value as PTT0；
S709, PTT0Current pressure P0Storing; and executing steps S710 to S720;
s710, controlling a pump valve to inflate the cuff to be near (MAP-7) mmHg through an NIBP measuring module;
s711, collecting the PTT value within T seconds, and calculating the characteristic value PTT thereof1Recording the current cuff pressure P1;
s712, adding P1、PTT1Storing;
s713, carrying out step pressure relief, and judging whether the step pressure is greater than 0.6 × DBP; if yes, executing steps S714 to S716; otherwise, executing steps S717 to S720;
s714, controlling a pump valve to reduce the step pressure of the cuff by Delta P through an NIBP measurement module algorithm;
s717, collecting the PTT value in T seconds, and calculating the characteristic value PTT thereofiRecording the current cuff pressure Pi;
s716, adding Pi、PTTiStoring and returning to execute S713;
s717, opening the valve to deflate to enable the cuff pressure to be restored to the initial state;
s718, calculating a PTT calibration parameter K;
s719, calculating a PTT calibration parameter B;
s720, setting the calibration mark as TRUE, obtaining the calibrated blood pressure value, and ending the measurement.
Fig. 8 is a flowchart of a method for obtaining a PTT value according to an embodiment of the present disclosure.
As shown in fig. 8, the method specifically includes the following steps:
and S801, collecting ECG and PPG signals.
It should be noted that the ECG is generally called electrocardiaGram, i.e. ElectroCardioGram; the PPG is known as photoplethsmograph, PhotoPlethysmoGraphy.
The process of acquiring the ECG and the PPG can be completed by an ECG and PPG data acquisition module in a non-invasive blood pressure measurement device (such as a monitor), that is, raw data of ECG and PPG signals of a detected object are acquired in real time by the ECG and PPG data acquisition module.
And S802, preprocessing the ECG and PPG signals.
After the raw data of the ECG and PPG signals are acquired, the raw data can be processed through an ECG and PPG data processing module, including real-time low-pass filtering and high-pass filtering, and high-frequency burrs and base drift are eliminated respectively.
And S803, detecting characteristic points of ECG and PPG waveforms.
And detecting waveform characteristic points of the processed ECG and PPG signals. The process is completed by a feature point detection module. Specifically, the feature point detection module detects feature points of waveforms of the ECG and PPG signals in real time, respectively, where the feature points may be R-wave peak points, R-wave valley values, and intermediate values (time points corresponding to peak-trough time averages or median amplitudes) of the ECG and PPG signals. In this embodiment, it is preferable to select the R-wave peak as the feature point of the ECG, and the PPG feature point may select a valley point, a maximum slope point, and a peak point.
S804, judging whether ECG and PPG characteristic points are detected; if yes, go to step S805; otherwise, the process returns to step S801.
And S805, calculating the PTT of the current heartbeat.
Detecting the physical time T between the same type of characteristic points of the ECG and the PPG which belong to the same heart beat1、T2The time difference of (A) is taken as the pulse wave transmission time PTT (T) corresponding to the heartbeat2-T1Thereby obtaining a measured PTT value.
In order to realize the embodiment, the invention also provides a noninvasive blood pressure measuring device based on the pulse wave propagation time PTT.
Fig. 9 is a schematic structural diagram of a noninvasive blood pressure measuring device based on the pulse wave propagation time PTT according to an embodiment of the present invention. As shown in fig. 9, the apparatus includes:
a first obtaining module 901, configured to obtain a first PTT characteristic value when the cuff pressure is 0 mmHg;
a control module 902 for controlling the cuff pressure to a target pressure;
a second obtaining module 903, configured to perform step pressure relief on the cuff, and obtain a second PTT characteristic value when the pressure of two or more different steps is not 0 mmHg;
and the processing module 904 is configured to obtain a blood pressure value of the detected object according to the first PTT characteristic value and the two or more second PTT characteristic values.
Further, the second obtaining module 903 is further configured to:
when the pressure is released to one step pressure each time, at least one PTT value of the tested object under the step pressure is obtained;
and acquiring a second PTT characteristic value under the step pressure according to the at least one PTT value.
Further, the second obtaining module 903 is further configured to:
acquiring a reference blood pressure value of a measured object, wherein the reference blood pressure value at least comprises diastolic pressure and systolic pressure;
determining the average pressure of the measured object according to the reference blood pressure value;
and determining the target pressure according to the average pressure.
Further, the second obtaining module 903 is further configured to:
judging whether the current step pressure is greater than a preset step pressure threshold value or not;
if the current step pressure is larger than the preset step pressure threshold value, step pressure relief is continuously carried out;
and if the current step pressure is less than or equal to the preset step pressure threshold, controlling the pressure relief of the cuff to an initial state.
Further, the second obtaining module 903 is further configured to:
detecting pulse waves in real time in the process of releasing pressure from the previous step to the current step each time;
judging whether a first peak value appears in the trend formed by the pulse waves, wherein the first peak values are preset multiples of two adjacent peak values of the first peak value respectively;
and when the pulse wave is judged to have the first peak value, acquiring a second PTT characteristic value corresponding to the current step pressure.
Further, the second obtaining module 903 is further configured to:
after judging that the pulse wave has a first peak value, judging whether the diastolic pressure of the detected object is detected;
if the diastolic pressure of the detected object is detected, acquiring a reference blood pressure value;
controlling the pressure of the cuff to be released to the initial state.
Further, the processing module 904 is further configured to:
acquiring the width of a cuff, the distance between specified points of a detected object and a reference blood pressure value of the detected object;
acquiring calibration parameters for calibrating the blood pressure according to the first PTT characteristic value, the second PTT characteristic value, the cuff pressure value corresponding to the second PTT characteristic value, the width, the distance and the reference blood pressure value;
and calibrating the reference blood pressure value according to the calibration parameters and the real-time measured PTT value to obtain a calibrated blood pressure value of the detected object.
Further, the processing module 904 is further configured to:
acquiring a first calibration parameter for correcting the blood pressure according to the first PTT characteristic value, the second PTT characteristic value and the cuff pressure value corresponding to the second PTT characteristic value, the width and the distance;
and acquiring a second calibration parameter for correcting the blood pressure according to the first PTT characteristic value, the first calibration parameter and the reference blood pressure value.
Further, the processing module 904 obtains a specific formula of the first calibration parameter for correcting the blood pressure as follows:
K＝(ln(PTTi-(L2-L1)/L2*PTT0)-ln(PTTj-(L2-L1)/L2*PTT0))/(Pi–Pj)
where K is the first calibration parameter, PTT0Is a first PTT feature value, PTTi、PTTjIs the second PTT feature value, Pi、PjAre respectively PTTi、PTTjCorresponding cuff pressure value, L1Width of the cuff, L2The distance between points is specified for the detected object.
Further, the specific formula of the processing module 904 for obtaining the second calibration parameter for correcting the blood pressure is as follows:
B＝PTT0/exp(-K*BP0)
wherein B is a second calibration parameter, BP0Is a reference blood pressure value.
Further, the specific formula for the processing module 904 to calibrate the reference blood pressure value according to the calibration parameter and the real-time measured PTT value is as follows:
BP＝(ln(B)–ln(PTT))/K
in the formula, BP is a calibrated blood pressure value, and PTT is a PTT value measured in real time.
Further, the processing module 904 is further configured to:
when the second PTT characteristic values are more than two, combining the second PTT characteristic values in pairs;
for each combination, inputting the second PTT characteristic value and the corresponding cuff pressure value in the combination into a calculation formula of the first calibration parameter, and determining a candidate first calibration parameter;
and determining final first calibration parameters according to the candidate first calibration parameters of all the combinations.
Further, the processing module 904 is further configured to:
acquiring the relative height between the designated points of the detected object;
and if the relative height is larger than the preset value, calibrating the PTT value measured in real time.
Further, the specific formula for the processing module 904 to calibrate the real-time measured PTT value is as follows:
PTTx＝(L*ρ*g*M)/(1-exp(-M*ρ*g*h)*PTTy)
wherein, PTTxFor the calibrated PTT value, L is the distance between the designated points of the detected object, ρ is the blood density, g is the gravitational acceleration, M is a constant, h is the relative height, PTT is the measured objectyIs a real-time measured PTT value.
It should be understood that the above-mentioned apparatus is used for executing the method in the above-mentioned embodiments, and the implementation principle and technical effect of the apparatus are similar to those described in the above-mentioned method, and the working process of the apparatus may refer to the corresponding process in the above-mentioned method, and is not described herein again.
In summary, in the noninvasive blood pressure measuring device based on PTT according to this embodiment, after the first obtaining module obtains the first PTT characteristic value when the cuff pressure is 0mmHg, the control module controls the cuff pressure to the target pressure; then, a second acquisition module performs step pressure relief on the cuff to acquire a second PTT characteristic value of the cuff under different step pressures of not 0 mmHg; further, the processing module obtains the blood pressure value of the detected object according to the first PTT characteristic value and the plurality of second PTT characteristic values. The device obtains the first PTT characteristic value and two or more than two second PTT characteristic values in the process of measuring the blood pressure of the detected object, so that the operation for obtaining the blood pressure value of the detected object is simple, the implementation is easy, the reliability is high, and the device has no special requirements on the measurement environment and can adapt to different clinical environments.
In order to implement the above embodiments, the present invention further provides a medical device, as shown in fig. 10, the electronic device includes a memory 1001, a processor 1002; wherein the processor 1002 runs a program corresponding to the executable program code by reading the executable program code stored in the memory 1001, so as to implement the steps of the above method. Wherein the medical device may be a monitor.
In order to implement the above embodiments, the present invention also provides a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, implements the steps of the above method.
In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. It will be understood by those of ordinary skill in the art that the above terms are used in the present invention as appropriate
The specific meanings of (A) and (B).
In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims (13)

1. A pulse wave propagation time (PTT) -based noninvasive blood pressure measurement method is characterized by comprising the following steps:
acquiring a first PTT characteristic value when the cuff pressure is 0 mmHg;
controlling the cuff pressure to a target pressure;
performing step pressure relief on the cuff to obtain a second PTT characteristic value of the cuff under different step pressures of two or more than two steps, wherein the second PTT characteristic value is not 0 mmHg;
and acquiring the blood pressure value of the detected object according to the first PTT characteristic value and two or more second PTT characteristic values.
2. The method of claim 1, wherein the step venting the cuff to obtain the second PTT characteristic value at non-0 mmHg at two or more different step pressures comprises:
when the pressure is released to one step pressure each time, at least one PTT value of the tested object under the step pressure is obtained;
and acquiring a second PTT characteristic value under the step pressure according to the at least one PTT value.
3. The method of claim 2, further comprising, prior to said controlling said cuff pressure to a target pressure:
acquiring a reference blood pressure value of the measured object, wherein the reference blood pressure value at least comprises diastolic pressure and systolic pressure;
determining the average pressure of the measured object according to the reference blood pressure value;
and determining the target pressure according to the average pressure.
4. The method of claim 3, further comprising:
judging whether the current step pressure is greater than a preset step pressure threshold value or not;
if the current step pressure is larger than the preset step pressure threshold value, continuing to perform step pressure relief;
and if the current step pressure is less than or equal to the preset step pressure threshold, controlling the cuff pressure to be decompressed to an initial state.
5. The method of claim 2, wherein before obtaining the second PTT characteristic value at the step pressure, further comprising:
detecting pulse waves in real time in the process of releasing pressure from the previous step to the current step each time;
judging whether a first peak value appears in the trend formed by the pulse waves, wherein the first peak value is respectively a preset multiple of the peak values on two adjacent sides of the first peak value;
and when the first peak value of the pulse wave is judged to appear, a second PTT characteristic value corresponding to the current step pressure is obtained.
6. The method of claim 5, further comprising:
after the pulse wave is judged to have the first peak value, judging whether the diastolic pressure of the detected object is detected or not;
if the diastolic pressure of the detected object is detected, acquiring the reference blood pressure value;
and controlling the pressure relief of the cuff to an initial state.
7. The method according to any one of claims 1 to 6, wherein the obtaining the blood pressure value of the detected object according to the first PTT feature value and two or more second PTT feature values comprises:
acquiring the width of the cuff, the distance between specified points of the detected object and a reference blood pressure value of the detected object;
acquiring calibration parameters for calibrating blood pressure according to the first PTT characteristic value, the second PTT characteristic value and cuff pressure values corresponding to the second PTT characteristic value, the width, the distance and the reference blood pressure value;
and calibrating the reference blood pressure value according to the calibration parameter and the PTT value measured in real time to obtain the blood pressure value of the detected object.
8. The method of claim 7, wherein the obtaining calibration parameters for calibrating blood pressure according to the cuff pressure values corresponding to the first PTT feature value, the second PTT feature value and the second PTT feature value, and the width, the distance and the reference blood pressure value comprises:
acquiring a first calibration parameter for correcting the blood pressure according to the first PTT characteristic value, the second PTT characteristic value and the cuff pressure value corresponding to the second PTT characteristic value, the width and the distance;
and acquiring a second calibration parameter for correcting the blood pressure according to the first PTT characteristic value, the first calibration parameter and the reference blood pressure value.
9. The method of claim 8, further comprising:
when the second PTT characteristic values are more than two, combining the second PTT characteristic values in pairs;
inputting the second PTT characteristic value and the corresponding cuff pressure value in each combination into a calculation formula of the first calibration parameter to determine a candidate first calibration parameter;
determining the final first calibration parameter according to the candidate first calibration parameters of all combinations.
10. The method of claim 8, further comprising:
acquiring the relative height between the appointed points of the detected object;
and if the relative height is larger than a preset value, calibrating the real-time measured PTT value.
11. A PTT-based non-invasive blood pressure measurement apparatus, the apparatus comprising:
the first acquisition module is used for acquiring a first PTT characteristic value when the cuff pressure is 0 mmHg;
a control module for controlling the cuff pressure to a target pressure;
the second acquisition module is used for carrying out step pressure relief on the cuff to acquire a second PTT characteristic value which is not 0mmHg under two or more different step pressures;
and the processing module is used for acquiring the blood pressure value of the detected object according to the first PTT characteristic value and two or more second PTT characteristic values.
12. A medical device comprising a memory, a processor;
wherein the processor runs a program corresponding to the executable program code by reading the executable program code stored in the memory for implementing the PTT-based noninvasive blood pressure measurement method of any one of claims 1-10.
13. A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out the PTT-based noninvasive blood pressure measuring method of any one of claims 1-10.
CN201910482921.9A 2019-06-04 2019-06-04 Medical equipment and PTT-based noninvasive blood pressure measurement method and device thereof Pending CN112022128A (en)

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