Method and device for processing blood pressure measurement signals and blood pressure storage data, storage medium, computer program product and external defibrillation monitor

Abstract

The invention provides a method, a device, a storage medium, a computer program product and an external defibrillation monitor for processing blood pressure measurement signals and blood pressure storage data. A method for processing a blood pressure measurement signal includes: determining a characteristic of each pulsation in a pressure measurement as a function of time; comparing the characteristics of the pulsations and determining a first number of consistent pulsations in the pressure measurements, the first number being greater than or equal to two, the difference between the characteristics of the consistent pulsations being less than a predetermined characteristic threshold; calculating a pulsation amplitude ratio between the average pulsation amplitude and a preceding average pulsation amplitude and comparing it to a predetermined pulsation amplitude ratio threshold; in response to the pulsation amplitude ratio being less than a pulsation amplitude ratio threshold, storing the cuff pressure value and an average pulsation amplitude; repeating the steps for each deflation; and calculating an average arterial pressure, systolic pressure, and diastolic pressure using the plurality of cuff pressure values and the plurality of average pulsation amplitudes for the successive deflation.

Description

Technical Field

[0001] This invention relates to the field of non-invasive blood pressure measurement technology, specifically to a method for processing blood pressure measurement signals and a method for processing blood pressure storage data, as well as corresponding devices, storage media, computer program products, and external defibrillator monitors. Background Technology

[0002] Cardiac arrest and other heart health conditions are leading causes of death worldwide. Various resuscitation efforts aim to maintain the body's circulatory and respiratory systems during cardiac arrest in an attempt to save the life of the subject. External defibrillators (such as manual defibrillators or automated external defibrillators (AEDs)) have significantly improved the ability to treat these conditions. These devices monitor the subject's vital signs and, upon detecting a life-threatening health event (such as ventricular fibrillation and ventricular tachycardia), treat the subject by applying a corrective electrical impulse to the heart. Examples of external defibrillators are AEDs from a medical company located in Chelmsford, Massachusetts.

[0003] Such external defibrillator monitors can include the measurement of the subject's blood pressure, thereby enabling the assessment of health events and / or control of treatment delivery based on the blood pressure measurement results. Such blood pressure measurement is typically achieved through non-invasive blood pressure measurement techniques (NIBP). NIBP techniques include palpation, auscultation, ultrasound, and oscillometric methods. Summary of the Invention

[0004] According to a first aspect of this application, a method for processing a blood pressure measurement signal is provided, characterized in that the blood pressure measurement signal includes a series of pressure measurements representing a pressure change over time in a blood pressure cuff, the blood pressure cuff being inflated to an initial inflation pressure and then successively deflated, and the series of pressure measurements being measured using a pressure sensor after each of the successively deflated pressures and before the start of the next deflation, the method comprising: a characteristic determination step for determining the characteristics of each pulsation in the time-varying pressure measurements measured after the previous deflation (i.e., the i-th deflation) and before the start of the next deflation (i+1)-th deflation, where i is a positive integer; and a consistent pulsation determination step for comparing the characteristics of the pulsations and determining a first number of consistent pulsations in the pressure measurements based on the comparison. In the process, the first quantity is greater than or equal to two, and the difference between the characteristics of the consistent pulsation is less than a predetermined characteristic threshold; an amplitude comparison step is used to calculate the pulsation amplitude ratio between the average pulsation amplitude after the last deflation (i.e., after the i-th deflation) and the prior average pulsation amplitude after the second-to-last deflation (i.e., after the (i-1)-th deflation), and compare the pulsation amplitude ratio with a predetermined pulsation amplitude ratio threshold; a storage step is used to store the cuff pressure value and the average pulsation amplitude in response to the pulsation amplitude ratio being less than the pulsation amplitude ratio threshold; the characteristic determination step, the consistent pulsation determination step, the amplitude comparison step, and the storage step are repeated for each deflation in the successive deflation; and the mean arterial pressure, systolic pressure, and diastolic pressure are calculated using the multiple cuff pressure values ​​and multiple average pulsation amplitudes stored for the successive deflation.

[0005] According to a second aspect of this application, an apparatus for processing blood pressure measurement signals is provided, characterized in that the apparatus is used in conjunction with a blood pressure cuff, the blood pressure cuff being inflated to an initial inflation pressure and subsequently deflated, the apparatus comprising: a pressure sensor for measuring a series of pressure measurements representing the pressure changing over time in the blood pressure cuff after each of the successive deflations and before the start of the next deflation, as the blood pressure measurement signal; and a processor configured to perform: a characteristic determination step for determining the characteristics of each pulsation in the pressure measurements measured over time after the previous deflation, i.e., the i-th deflation, and before the start of the next deflation, i.e., the (i+1)-th deflation, where i is a positive integer; and a consistent pulsation determination step for comparing the characteristics of the pulsations and determining, based on the comparison, the i-th pulsation in the pressure measurements. A number of consistent pulses, wherein the first number is greater than or equal to two, and the difference between the characteristics of the consistent pulses is less than a predetermined characteristic threshold; an amplitude comparison step for calculating the pulse amplitude ratio between the average pulse amplitude after the last deflation (i.e., after the i-th deflation) and the prior average pulse amplitude after the penultimate deflation (i.e., after the (i-1)-th deflation), and comparing the pulse amplitude ratio with a predetermined pulse amplitude ratio threshold; a storage step for storing the cuff pressure value and the average pulse amplitude in response to the pulse amplitude ratio being less than the pulse amplitude ratio threshold; repeating the characteristic determination step, the consistent pulse determination step, the amplitude comparison step, and the storage step for each deflation in the successive deflations; and calculating the mean arterial pressure, systolic pressure, and diastolic pressure using the multiple cuff pressure values ​​and multiple average pulse amplitudes stored for the successive deflations.

[0006] According to a third aspect of this application, a method for processing stored blood pressure data is provided, characterized in that the stored blood pressure data is measured and stored during successive deflation of a blood pressure cuff, and the stored blood pressure data includes cuff pressure values ​​and average pulse amplitude after each deflation, the method comprising: receiving the stored blood pressure data; generating an average pulse amplitude curve based on multiple cuff pressure values ​​and multiple average pulse amplitudes; calculating a fitting curve that best fits the average pulse amplitude curve; calculating the deviation between the corresponding average pulse amplitude and the fitting curve at each cuff pressure value; calculating the mean of the deviations based on the deviations at each cuff pressure value, and processing the mean of the deviations. The mean is compared with a predetermined deviation threshold; in response to the mean deviation being greater than the deviation threshold, the blood pressure storage data is determined to have motion artifacts; in response to the determination that the blood pressure storage data has motion artifacts, for each average pulse amplitude exceeding the fitted curve, the positive deviation between the average pulse amplitude and the fitted curve is calculated, and the positive deviation is compared with a predetermined positive deviation threshold; in response to the positive deviation being greater than the positive deviation threshold, the average pulse amplitude is replaced with the corresponding value on the fitted curve to obtain a modified average pulse amplitude; and the mean arterial pressure, systolic pressure, and diastolic pressure are calculated using the cuff pressure value and the modified average pulse amplitude.

[0007] According to a fourth aspect of this application, an apparatus for processing blood pressure storage data is provided, characterized in that the blood pressure storage data is measured and stored during successive deflation of a blood pressure cuff, and the blood pressure storage data includes cuff pressure values ​​and average pulse amplitude after each deflation. The apparatus includes: an input unit for receiving the blood pressure storage data; and a processor configured to: generate an average pulse amplitude curve based on multiple cuff pressure values ​​and multiple average pulse amplitudes; calculate a fitting curve that best fits the average pulse amplitude curve; calculate the deviation between the corresponding average pulse amplitude and the fitting curve at each cuff pressure value; and calculate the mean deviation of the deviation based on the deviation at each cuff pressure value. The blood pressure data is analyzed and the mean of the deviation is compared with a predetermined mean deviation threshold. If the mean deviation is greater than the mean deviation threshold, the stored blood pressure data is determined to have motion artifacts. In response to the determination that the stored blood pressure data has motion artifacts, for each average pulse amplitude exceeding the fitted curve, a positive deviation between the average pulse amplitude and the fitted curve is calculated, and the positive deviation is compared with a predetermined positive deviation threshold. If the positive deviation is greater than the positive deviation threshold, the average pulse amplitude is replaced with the corresponding value on the fitted curve to obtain a modified average pulse amplitude. The cuff pressure value and the modified average pulse amplitude are used to calculate mean arterial pressure, systolic pressure, and diastolic pressure.

[0008] Other features and aspects of the invention will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0009] The accompanying drawings, which are included in and form part of this specification, illustrate exemplary embodiments, features, and aspects of the invention together with the specification and serve to explain the principles of the invention.

[0010] Figure 1 This is a block diagram of a blood pressure measuring device according to an embodiment of the present invention.

[0011] Figure 2 This is a schematic diagram showing the deflation process of a blood pressure measuring cuff.

[0012] Figure 3A This is a schematic diagram showing the peak-to-peak amplitude of the pulsation in the pressure measurement after multiple deflations of a blood pressure cuff under ideal conditions.

[0013] Figure 3B This is a schematic diagram showing the peak-to-peak amplitude of the pulsation in the pressure measurement after multiple deflations of a blood pressure cuff under conditions of motion artifact contamination.

[0014] Figure 4 This is a flowchart illustrating a method for processing blood pressure measurement signals according to an embodiment of this application.

[0015] Figure 5 This illustrates a consistent pulsation determined in pressure measurements according to an embodiment of this application.

[0016] Figure 6 This is a flowchart of a method for processing stored blood pressure data according to an embodiment of this application.

[0017] Figure 7 An average pulsation curve generated based on stored blood pressure data is shown according to an embodiment of this application.

[0018] Figure 8 This is a schematic diagram illustrating a Gaussian fitting curve according to an embodiment of this application.

[0019] Figure 9 This is a schematic diagram illustrating an embodiment of the present application of replacing the average pulsation amplitude with a positive deviation greater than a positive deviation threshold.

[0020] Figure 10 A graph showing the modified average pulsation amplitude and cuff pressure value according to an embodiment of this application is provided. Detailed Implementation

[0021] Various exemplary embodiments, features, and aspects of the present invention will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0022] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0023] Furthermore, to better illustrate the present invention, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that the present invention can be practiced without certain specific details. In other instances, methods, means, elements, and circuits well known to those skilled in the art have not been described in detail in order to highlight the spirit of the invention.

[0024] Oscilloscope-based blood pressure measurement devices include a cuff, pump, pressure sensor, valve, and processing unit. The pump inflates the cuff, and the valve opens or closes to inflate or deflate the cuff. The pressure sensor obtains a pressure measurement value representing the pressure in the cuff. To initiate blood pressure measurement, the valve is closed, the pump is turned on, and the cuff is inflated, increasing the cuff pressure to the initial inflation pressure. Once the cuff pressure reaches its initial inflation pressure, the blood pressure monitor deflates the cuff in small pressure steps (e.g., 5-10 mmHg), and after the cuff pressure drops to a new value, the pressure in the cuff is measured and recorded. Due to the heartbeat, the arterial volume changes, causing the pressure in the cuff measured by the pressure sensor to change after each deflation and before the next deflation, producing an oscillation, or pulsation. The amplitude of this pulsation is also measured and recorded after each deflation and before the next deflation. Then, the next deflation begins. Repeat the above procedure until the amplitude of the pulsation in the cuff pressure drops back to a predetermined proportion of the peak value after reaching its peak. At this point, the blood pressure measurement cycle ends, the valve opens, and the cuff is fully deflated.

[0025] Conventional oscillometric blood pressure measurement techniques rely on empirical evidence. The amplitude of the pulsation measured in the blood pressure cuff reaches its maximum when the cuff pressure is close to the subject's mean arterial pressure (MAP). Systolic and diastolic blood pressure are then obtained based on clinical experience using the mean arterial pressure.

[0026] However, conventional oscillometric blood pressure measurement techniques have limitations. For example, during blood pressure measurement, the subject's movement, especially the movement of the arm and / or cuff, can increase the amplitude of the pulse; the cuff pressure measured in this case can be considered a mixture of blood pressure and motion artifacts. The presence of motion artifacts will affect the accurate measurement of the pulse amplitude, and thus the accuracy of the final blood pressure measurement result.

[0027] The above-mentioned technical problems can be solved by the method provided by this invention. In the method provided in this application, on the one hand, in the pressure measurement values ​​taken after each deflation of the cuff, pulsations that may be affected by motion artifacts are excluded "in real time," and the amplitude of the pulsations is calculated based on the pulsations unaffected by motion artifacts. On the other hand, in the "post-processing" after the cuff is fully deflated, pulsations affected by motion artifacts are identified among the recorded multiple pulsation amplitudes, and their amplitudes are corrected. Through these two aspects of processing, the influence of motion artifacts on the final blood pressure measurement result can be minimized, improving the accuracy of the entire blood pressure measurement.

[0028] Figure 1 This is a block diagram of a blood pressure measuring device 100, which includes a cuff 110, a pump 120, a valve 130, a pressure sensor 140, a processing device 150, a drive circuit 160 for driving the pump 120 and the valve 130, and a power supply 170.

[0029] The power source 170 can be a battery or an AC power source (e.g., 220V public power). The power source 170 supplies power to the main components of the blood pressure measuring device, in this example, to the pump 120, valve 130, pressure sensor 140, processing unit 150, and drive circuit 160.

[0030] The blood pressure measuring device 100 may further include an input device 112, which is used for inputting commands such as starting, stopping, and canceling blood pressure measurement. The input device 112 may also be used to input subject information, such as whether the subject is an adult or a child, to initially set the inflation and deflation of the cuff. Optionally, a push-button switch may be used as an example of the input device 112, but the input device 112 is not limited to a push-button switch; for example, it may be other contact input devices such as a pressure-sensitive (resistive) or proximity (capacitive) touch panel. Additionally, the input device 112 may be a voice input device with a microphone, or a communication input device capable of wired or wireless communication with a computer, smartphone, etc. Alternatively, the input device 112 may be any combination of contact input devices, voice input devices, and communication input devices.

[0031] The blood pressure measuring device 100 may also include an output device 114, which is typically a display, for example for providing information such as the final blood pressure measurement result. Optionally, the output device 114 may include one or more speakers for providing audible feedback, or other components (e.g., a printer) for providing other types of feedback (such as haptic / tactile feedback). Additionally, the screen may be a touchscreen display serving as a combined input / output device.

[0032] The processing device 150 includes a memory 152, a blood pressure measurement signal processing unit 154, and a blood pressure storage data processing unit 156.

[0033] The memory 152 in the processing device 150 stores data for controlling the blood pressure measurement signal processing unit 154 and the blood pressure storage data processing unit 156 and their programs, setting data for setting various parameters of the blood pressure measuring device, and data on the output results of the blood pressure measurement signal processing unit 154 and the blood pressure storage data processing unit 156. The memory 152 is used as working memory when executing programs. Here, the setting data for setting various parameters of the blood pressure measuring device includes: biological information input by the subject via the input device 112; the initial inflation pressure value for calculating the required air pressure to be supplied to the cuff based on the biological information; the predetermined deflation target value for each deflation in successive deflation; the time interval between two deflations in successive deflation; the initial inflation rate; the desired inflation rate; the desired deflation rate; and the predetermined time. Such setting data can also be obtained based on empirical data from previous blood pressure measurements and stored in the memory 152 for subsequent blood pressure measurements. In addition, memory 152 stores the results of multiple blood pressure measurements for the same subject for further trend analysis, which can then be used to assess the subject's clinical condition.

[0034] The blood pressure measurement signal processing unit 154 and the blood pressure storage data processing unit 156 in the processing device 150 are used together to process the pressure measurement values ​​from the pressure sensor 140, and ultimately obtain blood pressure measurement results including, for example, mean arterial pressure, systolic pressure, and diastolic pressure. In one possible implementation, during cuff deflation, the blood pressure measurement signal processing unit 154 processes the blood pressure measurement signal after each deflation in "real-time" until the cuff is completely deflated. This blood pressure measurement signal includes a series of pressure measurement values, measured by the pressure sensor 140, representing the pressure in the blood pressure measurement cuff changing over time. Additionally, after the cuff is completely deflated, the blood pressure storage data processing unit 156 performs "post-processing" on, for example, the output signal from the blood pressure measurement signal processing unit 154, i.e., the blood pressure storage data. This blood pressure storage data includes the cuff pressure value after each deflation and the amplitude of the pulsation in the pressure measurement values.

[0035] Figure 2 This is a schematic diagram illustrating the deflation process of a blood pressure measuring cuff. After the blood pressure measuring device 100 receives a command to start blood pressure measurement via the input device 112, the drive circuit 160 drives the pump 120 and valve 130 to inflate the cuff 110 to the expected target pressure. Then, the valve 130 is driven to deflate the cuff 110 sequentially in a series of predetermined small pressure steps, thereby completing the blood pressure measurement. During the sequential deflation of the cuff 110, the pressure sensor 140 continuously measures the pressure in the cuff 110 and provides the pressure measurement value to the processing device 150. Figure 2 As shown, after each deflation of the cuff 110, the pressure in the cuff 110 remains relatively stable, forming a "plateau". After several plateaus, the pressure value of the cuff 110 will become low enough that the cuff pressure measurement process can be ended, and the cuff 110 can be completely deflated. Figure 2 As shown, the pressure measurement values ​​in each platform oscillate due to changes in arterial volume, which is referred to here as "pulsation".

[0036] Figure 3A This is a schematic diagram illustrating the pulsating peak-to-peak amplitude in pressure measurements after multiple deflations of the cuff under ideal conditions. With each deflation, as... Figure 3A As shown in the upper part, the peak-to-peak amplitude of the pulsation initially increases, reaching its maximum at the mean arterial pressure, and then begins to decrease as the cuff pressure falls below the mean arterial pressure. An amplitude-pressure curve can be obtained based on the pressure measurements and the peak-to-peak amplitude of the pulsation, as shown below. Figure 3A As shown in the lower part. In Figure 3A In this example, the peak-to-peak amplitude of the pulsation is largest when the cuff pressure is 128 mmHg. In conventional oscillometric blood pressure measurement techniques, the mean arterial pressure can be defined as 128 mmHg.

[0037] However, as mentioned above, in actual blood pressure measurements, the cuff pressure readings may be affected by motion artifacts, which can cause an increase in the peak-to-peak amplitude of the pulsation. Figure 3B This is a schematic diagram illustrating the peak-to-peak amplitude of pulsations in blood pressure measurements after multiple deflations of a blood pressure cuff under conditions of motion artifact contamination. (Example) Figure 3B As shown, when the cuff pressure is 140 mmHg, the subject may have moved, and the motion artifact causes an abnormally large peak-to-peak amplitude of the pulsation in the pressure measurement at this plateau. This increased peak-to-peak amplitude of the pulsation may be mistaken for the maximum peak-to-peak amplitude value obtained during successive deflation of the cuff, or at least affect the judgment of the maximum peak-to-peak amplitude value, reducing the accuracy of the judgment.

[0038] To eliminate the effects of motion artifacts, the blood pressure measurement signal processing unit 154 performs... Figure 4 The method shown is for processing blood pressure measurement signals in a "real-time" manner after each deflation. Figure 4 A flowchart illustrating a method for processing a blood pressure measurement signal according to an embodiment of this application is provided. The method 400 for processing a blood pressure measurement signal according to an embodiment of this application includes:

[0039] S410: Determine the characteristics of each pulsation in the pressure measurement values ​​that change over time after the previous venting (denoted as the i-th venting) is completed and before the start of the next venting (denoted as the (i+1)-th venting), where i is a positive integer;

[0040] S420: Compare the characteristics of each pulse and determine a first number of consistent pulses in the pressure measurements based on the comparison;

[0041] S430: Calculate the pulse amplitude ratio between the average pulse amplitude after the last (i.e., the i-th) deflation and the previous average pulse amplitude after the second to last (i-1) deflation, and compare the pulse amplitude ratio with a predetermined pulse amplitude ratio threshold.

[0042] S440: If the pulsation amplitude ratio calculated from S430 is less than the pulsation amplitude ratio threshold, then store the cuff pressure value and average pulsation amplitude for the last deflation.

[0043] S450: Repeat steps S410 to S440 for each gas release in the successive gas release process; and

[0044] S460: Calculates mean arterial pressure, systolic pressure, and diastolic pressure using multiple cuff pressure values ​​and multiple average pulsation amplitudes stored for each successive deflation.

[0045] like Figure 2 As shown, after each deflation of the cuff, the pressure measurement value obtained by the pressure sensor 140 changes over time, comprising a series of pulses. The peak-to-peak amplitude of this series of pulses is of interest to oscillometric blood pressure measurement techniques. To characterize the peak-to-peak amplitude of this series of pulses, in one possible implementation, the average peak-to-peak amplitude of multiple pulses with good consistency in the series is determined as the average pulse amplitude of the series. To find multiple pulses with good consistency, the characteristics of each pulse must first be determined.

[0046] Step S410 can also be referred to as the characteristic determination step. In one possible implementation, the characteristic of the pulsation to be determined includes, for example, the amplitude of the pulsation, which refers to the peak-to-peak amplitude from the highest point to the lowest point in a pulsating waveform. This peak-to-peak amplitude can be easily calculated from the pressure measurement value from the pressure sensor 140. For example, the pressure measurement value from the pressure sensor 140 can be an analog voltage signal; after each venting, the analog voltage signal can be directly read and its range of variation measured as the peak-to-peak amplitude of the pulsation. The pressure measurement value from the pressure sensor 140 can also be converted into a digital signal through analog-to-digital (A / D) conversion, and the range of variation of the digital signal can be easily read as the peak-to-peak amplitude of the pulsation.

[0047] The characteristics of the pulsation to be determined may include, for example, the area covered by the pulsation waveform. Figure 3A or Figure 3B The waveform at the top shows a series of pulsating waveforms within a "plateau" after a single deflation. Note that the waveform here oscillates up and down around an amplitude of "0," and does not represent the absolute pressure value of that "plateau," i.e., the absolute pressure value of the cuff after this deflation. In such a pulsating waveform, the area covered by the pulsating waveform or a portion thereof can be calculated, for example, by integrating the absolute value of the pulsating waveform over time.

[0048] The characteristics of the pulse to be determined may include, for example, the time interval between consecutive pulses, which is related to the subject's heart rate. In one possible implementation, the time interval between consecutive pulses can be calculated by measuring the time interval between two peaks or two troughs, based on the measured peak-to-peak amplitude of the pulse. In another possible implementation, the time interval between consecutive pulses can be measured directly, for example, using a specialized sensor.

[0049] The characteristics of the pulsation to be determined may include, for example, the slope of the rising or falling edge of the pulsation. For instance, the slope can be calculated by measuring the time difference between peaks based on the peak-to-peak amplitude of the pulsation. Alternatively, it can be... Figure 3A or Figure 3B The slope is obtained through graphical analysis in the upper waveform diagram.

[0050] The characteristics of the pulses to be determined may include, for example, the duration of the pulses. For instance, given the time intervals between consecutive pulses, the duration of a single pulse can be calculated indirectly. Or, for example, it can be... Figure 3A or Figure 3B The duration of a single pulse is obtained through graphical analysis in the upper waveform diagram.

[0051] Those skilled in the art can also think of other ways to measure characteristics such as the amplitude of the pulsation, the area of the pulsation waveform, the time period between consecutive pulsations, the slope, and the duration. The present application does not limit this here.

[0052] After determining the characteristics of each pulsation in step S410, step S420 can be executed next to compare the characteristics between each pulsation to determine consistent pulsations. Step S420 can also be referred to as the consistent pulsation determination step. In one possible implementation, corresponding characteristic thresholds can be set for each characteristic. If the difference in a specific characteristic between two pulsations is less than the corresponding characteristic threshold, then these two pulsations are considered to be consistent. For example, the duration of the pulsation can be selected for comparison, and the characteristic threshold is set to 200 ms. That is, if in two pulsations, the difference between the duration of the first pulsation and the duration of the second pulsation is less than 200 ms, then these two pulsations are considered to be consistent with respect to the duration. In a preferred implementation, the durations of two pulsations are compared in the form of a ratio. For example, the characteristic threshold can be set to 20%; if the difference between the duration T1 of the first pulsation and the duration T2 of the second pulsation is less than 20% of one of them (T1 or T2), that is, |T2 - T1| < T1 * 0.2 or |T2 - T1| < T2 * 0.2, then these two pulsations are considered to be consistent with respect to the duration of the pulsation. Another example is that the amplitude of the pulsation can be selected for comparison. The amplitude of this pulsation can have different units and values depending on the dynamic range and resolution of the pressure sensor and the supporting circuit used. For example, in Figure 3A the waveform diagram shown, the output of the pressure sensor is a voltage quantity, and the pulsation in the pressure measurement value varies within the range of -20 mV to 50 mV; the characteristic threshold is set to 10 mV. That is, if in two pulsations, the difference between the peak-to-peak amplitude of the first pulsation and the peak-to-peak amplitude of the second pulsation is less than 10 mV, then these two pulsations are considered to be consistent with respect to the amplitude of the pulsation. In a preferred implementation, the peak-to-peak amplitudes of two pulsations are compared in the form of a ratio. For example, the characteristic threshold can be set to 20%; if the difference between the peak-to-peak amplitude A1 of the first pulsation and the peak-to-peak amplitude A2 of the second pulsation is less than 20% of one of them (A1 or A2), that is, |A2 - A1| < A1 * 0.2 or |A2 - A1| < A2 * 0.2, then these two pulsations are considered to be consistent with respect to the amplitude of the pulsation. The specific values of the characteristic thresholds for each different characteristic can be flexibly set according to clinical statistical data and are not limited to the values in the above examples. Similarly, the area of the pulsation waveform, the time period between consecutive pulsations, and / or the slope can also be selected, corresponding characteristic thresholds can be set, and the consistency of two consecutive pulsations with respect to each characteristic can be judged by comparison. Specific descriptions are not provided here.

[0053] In one possible implementation, the pulses are compared based on characteristics such as amplitude, area of ​​the pulse waveform, time interval between consecutive pulses, slope, and duration. Only when both pulses are consistent across all these characteristics are they identified as consistent pulses. Alternatively, several characteristics can be selected for comparison to determine consistent pulses. Another example is comparing all the characteristics, but if a certain number of characteristics are judged to be consistent (e.g., if 3 out of 5 characteristics are judged to be consistent), the two pulses are identified as consistent pulses. Yet another example is assigning weights to the characteristics and calculating a weighted consistency score; two pulses that meet a certain consistency score threshold are identified as consistent pulses.

[0054] As described above, the average pulse amplitude of multiple pulses with good consistency is calculated to characterize the peak-to-peak amplitude of a series of pulses after the last venting. In one possible implementation, characteristics can be compared between any two pulses in the measured pressure values. For example, in a series of pulses in a "plateau" after the last venting, each time a new pulse is obtained by the sensor in chronological order, it is compared with each previously measured pulse in the same "plateau," thus obtaining a consistent pulse if the difference between the characteristics of the new pulse and the characteristics of one or more previously measured pulses is less than a characteristic threshold. Comparisons can also be made between consecutive pulses; that is, each time a new pulse is measured by the sensor, it is compared with the previous pulse to obtain consecutive consistent pulses. The number of consistent pulses to be determined (hereinafter referred to as the first number) is at least two. This first number can also be any positive integer greater than two. While a larger value for the first number may result in a more accurate calculated average pulse amplitude, it also increases the computation time. In a preferred implementation, two consistent pulses are determined in step S420. Figure 5 This illustrates a consistent pulsation determined in pressure measurements according to an embodiment of this application. For example... Figure 5 As shown, in the "plateau" at 75s, two consecutive consistent pulses P1 and P2, marked in red, are found in chronological order.

[0055] When pressure measurements are affected by motion artifacts or other interference, a series of pulses may not be consistent; in other words, a first number of consistent pulses may not be found in the "plateau" after the last deflation. To improve efficiency, in one possible implementation, a first predetermined time period can be set to determine the first number of consistent pulses. Step S420 can be performed on the pressure measurements within the first predetermined time period after the last deflation. If no first number of consistent pulses are found in the pressure measurements within the first predetermined time period, step S420 ends, and subsequent steps S430 and S440 are skipped, and the next deflation of the cuff 110 begins directly. In one possible implementation, the first predetermined time period is set to 12 seconds. Those skilled in the art can also conceive of setting the first predetermined time period to other values, which are not limited herein.

[0056] Furthermore, in practical applications, the first number of consistent pulses identified may not accurately represent the peak-to-peak amplitude of a series of pulses following the previous deflation. For example, two identified consistent pulses may both be affected by instantaneous motion artifacts; therefore, although these two consistent pulses have consistent peak-to-peak amplitudes, their average peak-to-peak amplitude may be excessively large compared to the peak-to-peak amplitudes of the subsequent series of pulses. To improve the accuracy of blood pressure measurement, it is necessary to identify and exclude such consistent pulses.

[0057] To identify consistent pulsations affected by motion artifacts, step S430, also known as the amplitude comparison step, is performed next. Figure 3A As shown in the graph below, under ideal conditions, the difference in average pulsation amplitude between two adjacent venting events is not too large. Therefore, a threshold can be set for this difference; if the difference between the peak-to-peak amplitudes of consistent pulsations in two consecutive "plateaus" is less than the threshold, then motion artifacts are considered to be absent; if the difference is greater than or equal to the threshold, then motion artifacts are considered to be present.

[0058] In one possible implementation, the average pulse amplitude after the previous (i-th) deflation is calculated based on the two consistent pulses obtained from step S420, and the pulse amplitude ratio between this average pulse amplitude and the previous average pulse amplitude after the penultimate (i-1) deflation is calculated. Figure 5 In this embodiment, the average peak-to-peak amplitude of the consistent pulses P1 and P2 obtained in step S410 can be calculated as the average pulse amplitude after venting at 23s. This average pulse amplitude can then be divided by the previous average pulse amplitude after the second-to-last venting (at 20s) (e.g., ...). Figure 5 (As shown in yellow), the pulsation amplitude ratio is obtained. Figure 5In the example, the average pulsation amplitude is expressed as a mV value; however, as mentioned above, the average pulsation amplitude can have different units and values ​​depending on the specific hardware settings used. Since step S430 calculates the ratio between the average pulsation amplitudes after two deflations, it is not affected by specific units or values.

[0059] Combination Figure 2 and Figure 3A It is understandable that as the cuff deflates with each inflation, the peak-to-peak amplitude of the pulsation in the pressure measurement first increases and then decreases. Therefore, when a measurable pulsation first appears in the pressure measurement, steps S410 and S420 can be executed to identify a consistent pulsation and calculate the average peak-to-peak amplitude of this consistent pulsation as the average pulsation amplitude after this inflation. This calculated average pulsation amplitude can then be used as the "previous average pulsation amplitude" after the next inflation. Iterating in this way during each inflation allows for the calculation of the corresponding pulsation amplitude ratio after each subsequent inflation. However, for the inflation step where a "measurable pulsation first appears," since the cuff pressure value is far from the mean arterial pressure at this point, for example... Figure 3A The lower curve corresponds to the position at the left end of the horizontal axis, so step S430 can be skipped after this venting.

[0060] The calculated pulse amplitude ratio is then compared with a predetermined pulse amplitude ratio threshold. For example, this threshold can be set to 120%. If the pulse amplitude ratio is less than 120%, meaning the increase in the average pulse amplitude after this deflation relative to the previous average pulse amplitude after deflation is less than 20% of the previous average pulse amplitude, then the increase is considered not excessive, and the consistent pulse determined in step S420 is deemed not to have motion artifacts. The specific value of the pulse amplitude ratio threshold can be flexibly set based on clinical statistical data, and is not limited to the value in the example above.

[0061] Next, step S440, also known as the "storage step," is performed. If the pulsation amplitude ratio calculated in step S430 is less than the pulsation amplitude ratio threshold, meaning the consistent pulsation determined in step S420 does not have motion artifacts, the average pulsation amplitude calculated based on this consistent pulsation and the corresponding cuff pressure value can be stored in memory 152 for subsequent calculations. The stored average arterial amplitude can be directly derived from the average arterial amplitude calculated in step S430. The stored cuff pressure value refers to the pressure level at the "plateau" after each deflation. Figure 2As shown, the pulsation is essentially a change in pressure measurement from a pressure sensor over time; therefore, the absolute pressure level of a consistent pulsation (e.g., its reading) can be used to represent the cuff pressure value. In one possible implementation, the average readings of each pulsation in the first number of consistent pulsations determined in step S420 can be used as the stored cuff pressure value. Those skilled in the art will also realize that other methods can be used to extract a reading from the first number of consistent pulsations as the stored cuff pressure value, and this application does not limit this.

[0062] If, through comparison of the pulse amplitude ratio in step S430 with a predetermined pulse amplitude ratio threshold, it is determined that the pulse amplitude ratio is greater than or equal to the predetermined pulse amplitude ratio threshold, it means that the average pulse amplitude after the previous (i-th) deflation has increased too much compared to the prior average pulse amplitude after the penultimate (i-1) deflation, and the corresponding consistent pulse may have motion artifacts and should be excluded. Figure 5 As shown, two consistent pulses, P1 and P2, were determined in chronological order after this deflation; however, through calculation and comparison in step S430, it was found that the average pulse amplitude of these consistent pulses P1 and P2 was different from the previous average pulse amplitude after the (i-1)th deflation (e.g., ...). Figure 5 The increase in amplitude (shown in yellow) is too large compared to the previous data, therefore it is determined that the consistent pulsations P1 and P2 may have motion artifacts, making it difficult to accurately characterize the peak-to-peak amplitude of a series of pulsations. Therefore, it is necessary to find other continuous consistent pulsations.

[0063] In this case, steps S432 and S434 are executed after step S430 of method 400. In step S432, another set of consistent pulses is determined by determining the characteristics of the pulses and comparing them with the pressure measurements after the previous (i-th) venting. In step S432, to improve the accuracy of the final average pulse amplitude, a second number of consecutive consistent pulses needs to be determined, wherein this second number is greater than the first number involved in step S420. In one possible implementation, the second number of consecutive consistent pulses is determined after the first number of consistent pulses found previously but which may be affected by motion artifacts. Figure 5 As shown, after pulses P1 and P2, three consecutive, consistent pulses P3, P4, and P5 were determined using a method similar to that in steps S410 and S420 (e.g. Figure 5 (As shown in blue). In another implementation, among all pulses after the last (i-th) deflation, for example in chronological order, a second number of consecutive consistent pulses are found by determining the characteristics of the pulses and comparing them. Figure 5As shown, characteristics can be determined and compared for (P1, P2 and P3) or (P2, P3 and P4); if the three pulses are consistent with each other, they are treated as three consecutive consistent pulses for subsequent calculations.

[0064] After determining the second number of consecutive consistent pulses, step S434 is executed. In step S434, based on the determined second number of consecutive consistent pulses, the absolute pressure level of the second number of consecutive consistent pulses is stored as the cuff pressure value, and the average peak-to-peak amplitude of the consistent pulses is stored as the average pulse amplitude. The method for obtaining the cuff pressure value and the average pulse amplitude in step S434 is similar to that in step S450 above, and will not be repeated here.

[0065] It is understandable that in some cases, after determining that a first number of consistent pulses are affected by motion artifacts, it may be impossible to find a second number of consecutive consistent pulses. To improve efficiency, in one possible implementation, a second predetermined time period can be set for determining the second number of consecutive consistent pulses. Step S432 can be performed on the pressure measurement values ​​within the second predetermined time period after the last deflation. If no second number of consecutive consistent pulses are found in the pressure measurement values ​​within the second predetermined time period, step S432 ends, and the subsequent step S434 is skipped, and the cuff 110 is deflated again (preferably with a smaller pressure step). In one possible implementation, the second predetermined time period is set to 20 seconds. Those skilled in the art can also conceive of setting the second predetermined time period to other values, which are not limited herein.

[0066] After storing the cuff pressure value and average pulsation amplitude after the previous deflation in step S440 or step S434, step S450 can be executed to start the next deflation of cuff 110, and steps S410 to S440 can be repeated for each deflation. This allows the storage of the cuff pressure value and average pulsation amplitude for each deflation.

[0067] After repeatedly deflating the cuff 110 and obtaining multiple cuff pressure values ​​and multiple average pulsation amplitudes, the repetition of steps S410 to S440 can be terminated, and the cuff 110 can be completely deflated to ambient atmospheric pressure. Figure 2As shown, during the successive deflation of the cuff 110, the average pulsation amplitude gradually increases initially, reaching its maximum when the cuff pressure equals the mean arterial pressure, and then decreases with each deflation. In one possible implementation, after step S440 is completed and before step S450 begins, in step S442, it can be determined whether the cycle from S410 to S440 should be stopped based on the stored changes in the average pulsation amplitude. For example, it can be determined that the cycle from S410 to S440 can be stopped and the cuff fully deflated when the stored average pulsation amplitude falls back to a predetermined percentage of the peak value after reaching its peak. This predetermined percentage can be flexibly set based on clinical statistics, for example, it can be 60%; those skilled in the art can also set the predetermined percentage to other values ​​as needed, and this application does not impose any limitations on this.

[0068] After stopping the cycle from S410 to S440 and fully deflating the cuff, step S460 can be executed to calculate the mean arterial pressure, systolic pressure, and diastolic pressure using multiple cuff pressure values ​​and multiple average pulse amplitudes stored for each deflation. In one possible implementation, in step S460, for example, the maximum value can be directly found from the multiple average pulse amplitudes recorded by the blood pressure measurement signal processing unit 154, and the corresponding cuff pressure value can be determined as the mean arterial pressure. Systolic pressure and diastolic pressure are then calculated based on this value. For details on calculating systolic and diastolic pressure based on mean arterial pressure, please refer to the following text. Figure 10 The description.

[0069] Method 400 allows, for example, the influence of motion artifacts on pressure measurements to be eliminated from the stored data; the final blood pressure measurement calculated based on such stored data will have higher accuracy compared to conventional blood pressure measurement techniques.

[0070] According to a preferred embodiment of this application, as a supplement or alternative to directly calculating the mean arterial pressure, systolic pressure, and diastolic pressure based on multiple stored cuff pressure values ​​and multiple average pulse amplitudes in step S460, further post-processing of the signal can be performed. To further eliminate the influence of motion artifacts on the final blood pressure measurement result and improve the accuracy of the final blood pressure measurement result, the blood pressure storage data processing unit 156 performs the following... Figure 6 The method shown for processing blood pressure storage data involves "post-processing" multiple cuff pressure values ​​and multiple average pulsation amplitudes from the blood pressure measurement signal processing unit 154. Figure 6 A flowchart illustrating a method for processing stored blood pressure data according to an embodiment of this application is provided. The method 600 for processing stored blood pressure data according to an embodiment of this application includes:

[0071] S610: Receives and stores blood pressure data;

[0072] S620: Generates an average pulsation amplitude curve based on multiple cuff pressure values ​​and multiple average pulsation amplitudes;

[0073] S630: Calculate the best fit curve to the average pulsation amplitude curve;

[0074] S640: At each cuff pressure value, calculate the deviation between the corresponding average pulsation amplitude and the fitted curve;

[0075] S650: Calculate the mean of the deviations based on the deviations at each of the pressure measurements, and compare the mean of the deviations with a predetermined mean deviation threshold.

[0076] S660: In response to the mean deviation being greater than the mean deviation threshold, it is determined that the blood pressure storage data has motion artifacts;

[0077] S670: In response to the determination that the blood pressure storage data has motion artifacts, for each average pulse amplitude exceeding the fitted curve, calculate the positive deviation between the average pulse amplitude and the fitted curve, and compare the positive deviation with a predetermined positive deviation threshold.

[0078] S680: In response to the positive deviation being greater than a predetermined positive deviation threshold, the average pulsation amplitude is replaced with the corresponding value on the fitted curve to obtain a modified average pulsation amplitude; and

[0079] S690: Calculate mean arterial pressure, systolic pressure, and diastolic pressure using the cuff pressure value and the modified average pulsation amplitude.

[0080] After all the successive deflation of the cuff 110 is completed and all the cuff pressure values ​​and average pulse amplitudes obtained from the successive deflation become available, the blood pressure storage data processing unit 156 begins to execute method 600 to post-process the multiple cuff pressure values ​​and multiple average pulse amplitudes stored in the storage unit 152. Method 600 begins with step S610; in step S610, blood pressure storage data is received from the memory 152. The blood pressure storage data includes at least the multiple cuff pressure values ​​and multiple average pulse amplitudes after the successive deflation of the cuff 110.

[0081] In one possible implementation, the blood pressure storage data can be obtained using conventional detection methods in the prior art, such as directly using the peak-to-peak amplitude of the pulsation and the absolute pressure level from the pressure measurement from the pressure sensor as the blood pressure storage data.

[0082] In a preferred implementation, the blood pressure storage data includes multiple cuff pressure values ​​and multiple average pulse amplitudes stored in the memory 152 by the method 400 described above. In other words, the output of method 400 can be processed as the input of method 600.

[0083] After receiving the stored blood pressure data, step S620 is executed. In step S620, based on multiple cuff pressure values ​​and multiple average pulse amplitudes in the stored blood pressure data, an average pulse amplitude curve is generated with the cuff pressure value on the horizontal axis and the average pulse amplitude on the vertical axis. Figure 7 An average pulsation curve generated based on stored blood pressure data is shown according to an embodiment of this application. Figure 7 The exemplary curve includes 10 sets of cuff pressure values ​​and corresponding average pulse amplitudes. However, those skilled in the art will understand that blood pressure storage data can include more sets of cuff pressure values ​​and average pulse amplitudes, and this application does not limit this.

[0084] As previously combined Figure 3B As described, certain mean pulsation amplitude data may be abnormally increased when affected by motion artifacts. Figure 7 In the exemplary mean pulsation curve, when the cuff pressure is approximately 140 mmHg, motion artifacts cause an abnormal mean pulsation amplitude, which may ultimately affect the determination of the maximum mean pulsation amplitude, thereby reducing the accuracy of the calculated mean arterial pressure, systolic pressure, and diastolic pressure. Therefore, it is necessary to correct for this abnormal mean pulsation amplitude.

[0085] After obtaining the average pulsation curve in step S620, step S630 is then performed to calculate the fitting curve that best fits the average pulsation amplitude curve.

[0086] In one possible implementation, the fitting curve used to fit the average pulsation amplitude curve is a Gaussian curve. Gaussian curve fitting is a common method in probability and statistics. It uses a Gaussian function to fit two-dimensional data, thereby describing the trend or pattern of the data. The Gaussian function, also known as the normal distribution function, has a bell-shaped shape. A one-dimensional Gaussian function can be expressed as...

[0087]

[0088] Where a represents the height of the bell curve peak, b represents the center coordinate of the bell curve, and c represents the standard deviation of the two-dimensional data, corresponding to the width of the bell.

[0089] By adjusting the values ​​of the above parameters, the Gaussian curve is fitted to the two-dimensional data. In one possible implementation, step S630 can be achieved using functions built into libraries of various programming languages ​​or data processing software. For example, in Python, Gaussian curve fitting can be achieved by referencing the cairo library; in MATLAB, the fit function or lsqcurvefit function can be used; and in OpenCV, the cv2.fitGaussianMB function can be used. Those skilled in the art can also conceive of other methods to achieve Gaussian curve fitting for the average pulsation amplitude curve, and this application does not impose any limitations on these methods.

[0090] In one possible implementation, the fitting curve used to fit the average pulsation amplitude curve is a cubic spline curve. Similar to the fitting using a Gaussian curve described above, step S630 can be implemented using functions built into the libraries of various programming languages ​​or data processing software. For example, in MATLAB, the `fit` or `csapi` functions can be used to implement cubic spline curve fitting. Those skilled in the art will also conceive of other ways to implement cubic spline curve fitting for the average pulsation amplitude curve, and this application does not impose any limitations thereon.

[0091] For ease of description, Gaussian curve fitting will be used as an example below. Figure 8 A schematic diagram of a Gaussian fitting curve according to an embodiment of this application is shown. It can be seen that there is a certain deviation between the average pulsation curve obtained in step S620 and the Gaussian curve. Ideally, the average pulsation curve should substantially conform to a normal distribution, i.e., substantially match the Gaussian curve; however, the value of the average pulsation amplitude affected by motion artifacts may significantly deviate from the Gaussian curve. Method 600 is needed to correct such an average pulsation amplitude to eliminate the influence of motion artifacts and improve the accuracy of blood pressure measurement.

[0092] After calculating the best-fitting curve in step S630, step S640 is executed to calculate the deviation between the average pulsation amplitude and the fitted curve at each cuff pressure value. Similar to... Figure 7 , Figure 8The exemplary curve includes 10 sets of cuff pressure values ​​and average pulsation amplitude, where the horizontal axis represents the cuff pressure value, and the corresponding average pulsation amplitude value can be found at each cuff pressure value. Simultaneously, based on the fitted curve calculated in step S630, the corresponding value on the fitted curve is calculated, for example, by substituting each cuff pressure value into the fitted curve. For example, in the implementation using Gaussian curve fitting, each cuff pressure value can be substituted into Formula 1 above to calculate the corresponding value on the Gaussian curve. The difference between the average pulsation amplitude value and the value on the fitted curve is taken as the deviation between the average pulsation amplitude and the fitted curve. Specifically, the deviation at each cuff pressure value can be calculated as follows:

[0093] Deviation = absolute(mean pulsation amplitude – fitted curve) / mean pulsation amplitude (Formula 2)

[0094] Here, `absolute()` represents the absolute value operation. The deviation calculated according to Formula 2 above is in the form of a fraction or percentage.

[0095] Next, step S650 is executed. After calculating the deviation between the average pulsation amplitude and the fitted curve for each of the multiple cuff pressure values ​​in the stored blood pressure data, the mean of the deviations is calculated based on these deviations. Figure 8 In the example, the mean of 10 deviations at 10 cuff pressure values ​​is calculated, and the result is approximately 0.1% or 10%. In another implementation, a weighted average can be used. For example, for each deviation calculated in step S640, lower weights can be assigned to deviations at the extremes of the curve, and higher weights can be assigned to deviations in the middle of the curve, and then a weighted average can be calculated as the mean of the deviations. The specific weight values ​​can be determined by those skilled in the art based on experience or actual needs, and this application does not impose any limitations on this.

[0096] In step S650, the calculated mean of the deviation is further compared with a predetermined mean deviation threshold to determine whether the blood pressure storage data received in step S610 may have motion artifacts. For example, in Figure 8 In the example, the deviation from the mean threshold can be set to 0.08 or 8%. The specific value of the deviation from the mean threshold can be determined based on clinical statistics, and this application does not impose any restrictions on it.

[0097] Next, step S660 is executed. If, in step S650, it is determined through comparison that the deviation from the mean is greater than the deviation threshold, then it is judged that the blood pressure storage data has motion artifacts, that is, the average pulse amplitude is affected by motion artifacts. Figure 8 In the example above, the deviation from the mean was 10%, which is greater than the 8% deviation from the mean threshold, so the blood pressure storage data was judged to have motion artifacts.

[0098] If, in step S650, the deviation from the mean is determined to be less than or equal to the deviation from the mean threshold, then the blood pressure storage data is determined to be unaffected by motion artifacts and can be directly used, for example, in the calculation of mean arterial pressure, systolic pressure, and diastolic pressure in step S690.

[0099] Next, S670 is executed. If it is determined in step S660 that the blood pressure storage data is affected by motion artifacts, then for each average pulse amplitude that exceeds the fitted curve, the positive deviation between the average pulse amplitude and the fitted curve is calculated.

[0100] like Figure 8 As shown, relative to the fitted Gaussian curve, the average pulsation amplitude corresponding to each cuff pressure value may be numerically greater than the value on the Gaussian curve (the point of average pulsation amplitude is higher than the Gaussian curve) or less than the value on the Gaussian curve (the point of average pulsation amplitude is lower than the Gaussian curve). Based on clinical experience, motion artifacts usually cause an abnormal increase in the average pulsation amplitude; therefore, the correction mainly focuses on the points on the average pulsation amplitude curve that are higher than the Gaussian curve. Similar to step S640, based on the average pulsation amplitude of each cuff pressure value and the points on the Gaussian curve, the points on the average pulsation amplitude curve that are higher than the Gaussian curve can be easily found. Specifically, the positive deviation between the average pulsation amplitude and the Gaussian curve can be calculated using the following formula:

[0101] Positive deviation = (mean pulsation amplitude – fitted curve) / mean pulsation amplitude > 0 (Formula 3)

[0102] The positive deviation calculated using Formula 3 above is in the form of a fraction or percentage.

[0103] For calculated positive deviations, further processing of the corresponding average pulsation amplitude is required. However, if the deviation at a certain cuff pressure value is zero or negative, no further processing of the corresponding average pulsation amplitude is performed. Figure 8 In the examples, positive deviations can be found when the cuff pressure values ​​are approximately 142 mmHg, 108 mmHg, 102 mmHg, and 94 mmHg.

[0104] In step S670, after calculating each positive deviation, each positive deviation is compared with a predetermined positive deviation threshold to further determine the average pulsation amplitude that needs correction. Figure 8 In the example, the positive deviation threshold can be set to 20%, and the positive deviations calculated at cuff pressure values ​​of 142 mmHg, 108 mmHg, 102 mmHg, and 94 mmHg can be compared with this positive deviation threshold. The specific value of the positive deviation threshold can be determined based on clinical statistics, and this application does not impose any restrictions on it.

[0105] Next, in step S680, the average pulsation amplitude with a positive deviation greater than the positive deviation threshold is further processed; specifically, the average pulsation amplitude is replaced with the value on the corresponding fitted curve. Figure 9 This is a schematic diagram illustrating an embodiment of the present application of replacing the average pulsation amplitude with a positive deviation greater than a positive deviation threshold. Figure 9 It shows the relationship with Figure 8 The same average pulse amplitude curve and Gaussian fitted curve are used; for example, at a cuff pressure of approximately 142 mmHg, the positive deviation calculated according to Formula 3 is approximately 23%, which is greater than the positive deviation threshold of 20%. Therefore, the average pulse amplitude from the blood pressure storage data is replaced with the corresponding value on the Gaussian curve.

[0106] If, in step S670, the positive deviation is determined to be less than or equal to the positive deviation threshold through comparison, then it is not necessary to replace the corresponding average pulsation amplitude. Figure 9 In the example, although positive deviations were obtained at cuff pressure values ​​of 108 mmHg, 102 mmHg and 94 mmHg, the corresponding positive deviation values ​​were less than the positive deviation threshold of 20%, so no modification to the average pulsation amplitude was required.

[0107] After performing step S680, among all the average pulse amplitudes from the blood pressure storage data, the average pulse amplitudes with positive deviations greater than the positive deviation threshold are modified, while the remaining average pulse amplitudes (including average pulse amplitudes with zero or negative deviations, and average pulse amplitudes with positive deviations less than or equal to the positive deviation threshold) remain unchanged. The resulting set of such average pulse amplitudes is called the modified average pulse amplitude. In the modified average pulse amplitude, and therefore in the graph based on the modified average pulse amplitude and cuff pressure values, the effects of motion artifacts are eliminated. Figure 10 A graph showing the modified average pulsation amplitude and cuff pressure value according to an embodiment of this application is provided.

[0108] Finally, in step S690, the subject's mean arterial pressure, systolic pressure, and diastolic pressure can be calculated using the modified mean pulsation amplitude and cuff pressure value, according to the principles of oscillometric blood pressure measurement technology. Specifically, as follows... Figure 10 As shown, the maximum average pulse amplitude can be found from the curve based on the modified average pulse amplitude and cuff pressure value. The cuff pressure value corresponding to this maximum average pulse amplitude is determined as the subject's mean arterial pressure. Figure 10 The mean is approximately 108 mmHg; then, for example... Figure 10Find the first average pulsation amplitude, which is a predetermined first percentage (e.g., 66%) of the maximum average pulsation amplitude, on the left side of the curve shown (the side with the higher cuff pressure value). Determine the cuff pressure value corresponding to this first average pulsation amplitude as the systolic pressure. Figure 10 The average is approximately 140 mmHg; and in, for example Figure 10 On the right side of the curve shown (the side with lower cuff pressure), find the second average pulsation amplitude, which is a predetermined second percentage (e.g., 70%) of the maximum average pulsation amplitude. Determine the cuff pressure value corresponding to this second average pulsation amplitude as the systolic pressure. Figure 10 The mean is approximately 94 mmHg.

[0109] Please note that in Figures 7-10 In the example, the average pulsation amplitude is expressed in mV. However, as mentioned above, the average pulsation amplitude can have different units and values ​​depending on the specific hardware settings. Since the purpose of modifying the average pulsation amplitude in method 600 is to find the accurate maximum average pulsation amplitude and then use the corresponding cuff pressure value as the mean arterial pressure, the specific measurement and value of the average pulsation amplitude do not affect the implementation of method 600.

[0110] Method 600 yielded the final results of blood pressure measurements for the subjects, including mean arterial pressure, systolic pressure, and diastolic pressure, which eliminated the adverse effects of motion artifacts and improved the accuracy of blood pressure measurements.

[0111] Those skilled in the art will understand that Figure 4 The method 400 shown for "real-time" processing of blood pressure measurement signals and Figure 6 The method 600 shown for "post-processing" blood pressure storage data can be used in combination. That is, as described in the preferred embodiment above, method 400 is first used to process the pressure measurements during the gradual deflation of the cuff to obtain multiple cuff pressure values ​​and multiple average pulsation amplitudes. Then, method 600 is used to process the multiple cuff pressure values ​​and multiple average pulsation amplitudes to obtain the final mean arterial pressure, systolic pressure, and diastolic pressure. In another embodiment, method 400 and method 600 can also be used alone. For example, the pressure measurements during the gradual deflation of the cuff can be processed first using method 400, and then the mean arterial pressure, systolic pressure, and diastolic pressure can be calculated using conventional methods in the prior art instead of method 600, based on the multiple cuff pressure values ​​and multiple average pulsation amplitudes recorded by method 400; or, conventional methods in the prior art can be used first instead of method 400 to obtain the cuff pressure values ​​and average pulsation amplitudes at multiple platforms during the cuff deflation process from the output signal of the pressure sensor, and then the cuff pressure values ​​and average pulsation amplitudes can be post-processed using method 600 to calculate the final mean arterial pressure, systolic pressure, and diastolic pressure.

[0112] It is understood that the various implementation methods mentioned above in this disclosure can be combined with each other to form combined implementations without violating the principles and logic. Due to space limitations, this disclosure will not elaborate further.

[0113] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for processing blood pressure measurement signals, characterized in that, The blood pressure measurement signal includes a series of pressure measurements representing the pressure change over time in the blood pressure cuff, the blood pressure cuff being inflated to an initial inflation pressure and then successively deflated, and the series of pressure measurements being measured using a pressure sensor after each of the successive deflations and before the start of the next deflation, the method comprising: The characteristic determination step is used to determine the characteristics of each pulsation in the pressure measurement values ​​that change over time, measured after the previous venting, i.e., the i-th venting, and before the start of the next venting, i.e., the (i+1)-th venting, where i is a positive integer; A consistent pulsation determination step is used to compare the characteristics of each pulsation and determine a first number of consistent pulsations in the pressure measurement values ​​based on the comparison, wherein the first number is greater than or equal to two, and the difference between the characteristics of the consistent pulsations is less than a predetermined characteristic threshold. The amplitude comparison step is used to calculate the pulse amplitude ratio between the average pulse amplitude after the last venting (i.e., the i-th venting) and the previous average pulse amplitude after the second-to-last venting (i-1) venting, and compare the pulse amplitude ratio with a predetermined pulse amplitude ratio threshold. A storage step is used to store the cuff pressure value and the average pulsation amplitude in response to the pulsation amplitude ratio being less than the pulsation amplitude ratio threshold. The characteristic determination step, the consistent pulsation determination step, the amplitude comparison step, and the storage step are repeated for each gas release in the successive gas release process; and The mean arterial pressure, systolic pressure, and diastolic pressure are calculated using multiple cuff pressure values ​​and multiple average pulsation amplitudes stored for each successive deflation.

2. The method according to claim 1, characterized in that, The average pulsation amplitude represents the average peak-to-peak amplitude of the first number of consistent pulsations measured after the previous deflation, and The cuff pressure value represents the absolute pressure level of the first number of consistent pulsations.

3. The method according to claim 1, characterized in that, The consistent pulsation determination step is used to compare the characteristics of each pulsation in chronological order, and The method further includes: In response to the absence of the first number of consistent pulses in the pulses within a first predetermined time period after the previous deflation is completed, the amplitude comparison step and the storage step are skipped, and the next deflation is performed.

4. The method according to claim 1, characterized in that, The consistent pulsation determination step is used to compare the characteristics of each pulsation in chronological order, and The method further includes: In response to determining that the pulsation amplitude ratio is greater than or equal to the pulsation amplitude ratio threshold, a second number of continuous, consistent pulsations are determined from the pressure measurements that change over time, wherein the second number is greater than the first number. The absolute pressure levels of the second number of consecutive consistent pulsations are stored as cuff pressure values, and the average peak-to-peak amplitude of the second number of consecutive consistent pulsations is stored as the average pulsation amplitude.

5. The method according to claim 4, characterized in that, The second number of consecutive uniform pulses follows the first number of uniform pulses.

6. The method according to claim 4, characterized in that, The method further includes: The next venting is performed in response to the absence of the second number of continuous, consistent pulses within a second predetermined time period after the completion of the previous venting.

7. The method according to claim 1, characterized in that, The characteristics include at least one of the following: the amplitude of the pulsation, the area of ​​the pulsation waveform, the time interval between consecutive pulsations, the slope of the pulsation waveform, and the duration of the pulsation.

8. The method according to claim 1, characterized in that, For each gas release in the successive gas release process, the characteristic determination step, the consistent pulsation determination step, the amplitude comparison step, and the storage step are repeated until the stored average pulsation amplitude falls back to a predetermined proportion of the peak value after reaching the peak value.

9. The method according to claim 8, characterized in that, The predetermined ratio is 60%.

10. The method according to claim 1, characterized in that, The characteristic thresholds are determined based on clinical statistical data for each characteristic, and the pulsation amplitude ratio thresholds are determined based on clinical statistical data.

11. The method according to claim 1, characterized in that, The first number of consistent pulses are continuous pulses.

12. A device for processing blood pressure measurement signals, characterized in that, The device is used in conjunction with a blood pressure cuff, which is inflated to an initial inflation pressure and then deflated sequentially. The device includes: A pressure sensor is used to measure a series of pressure measurements, representing the pressure change over time in the blood pressure cuff, from the completion of each deflation in the successive deflation to the start of the next deflation, as the blood pressure measurement signal; as well as The processor, which is configured to execute: The characteristic determination step is used to determine the characteristics of each pulsation in the pressure measurement values ​​that change over time after the previous venting, i.e., the i-th venting, is completed and before the next venting, i.e., the (i+1)-th venting begins, where i is a positive integer; A consistent pulsation determination step is used to compare the characteristics of each pulsation and determine a first number of consistent pulsations in the pressure measurement values ​​based on the comparison, wherein the first number is greater than or equal to two, and the difference between the characteristics of the consistent pulsations is less than a predetermined characteristic threshold. The amplitude comparison step is used to calculate the pulse amplitude ratio between the average pulse amplitude after the last venting (i.e., the i-th venting) and the previous average pulse amplitude after the second-to-last venting (i-1) venting, and compare the pulse amplitude ratio with a predetermined pulse amplitude ratio threshold. A storage step is used to store the cuff pressure value and the average pulsation amplitude in response to the pulsation amplitude ratio being less than the pulsation amplitude ratio threshold. The characteristic determination step, the consistent pulsation determination step, the amplitude comparison step, and the storage step are repeated for each gas release in the successive gas release process; and The mean arterial pressure, systolic pressure, and diastolic pressure are calculated using multiple cuff pressure values ​​and multiple average pulsation amplitudes stored for each successive deflation.

13. The apparatus according to claim 12, characterized in that, The average pulsation amplitude represents the average peak-to-peak amplitude of the first number of consistent pulsations measured after the previous deflation, and The cuff pressure value represents the absolute pressure level of the first number of consistent pulsations.

14. The apparatus according to claim 12, characterized in that, The consistent pulsation determination step is used to compare the characteristics of each pulsation in chronological order, and The processor is also configured to: In response to the absence of the first number of consistent pulses in the pulses within a first predetermined time period after the previous deflation is completed, the amplitude comparison step and the storage step are skipped, and the next deflation is performed.

15. The apparatus according to claim 12, characterized in that, The consistent pulsation determination step is used to compare the characteristics of each pulsation in chronological order, and The processor is also configured to: In response to determining that the pulsation amplitude ratio is greater than or equal to the pulsation amplitude ratio threshold, a second number of continuous, consistent pulsations are determined from the pressure measurements that change over time, wherein the second number is greater than the first number. The absolute pressure levels of the second number of consecutive consistent pulsations are stored as cuff pressure values, and the average peak-to-peak amplitude of the second number of consecutive consistent pulsations is stored as the average pulsation amplitude.

16. The apparatus according to claim 15, characterized in that, The second number of consecutive uniform pulses follows the first number of uniform pulses.

17. The apparatus according to claim 15, characterized in that, The processor is also configured to: The next venting is performed in response to the absence of the second number of continuous, consistent pulses within a second predetermined time period after the completion of the previous venting.

18. The apparatus according to claim 12, characterized in that, The characteristics include at least one of the following: the amplitude of the pulsation, the area of ​​the pulsation waveform, the time interval between consecutive pulsations, the slope of the pulsation waveform, and the duration of the pulsation.

19. The apparatus according to claim 12, wherein, For each gas release in the successive gas release process, the characteristic determination step, the consistent pulsation determination step, the amplitude comparison step, and the storage step are repeated until the stored average pulsation amplitude falls back to a predetermined proportion of the peak value after reaching the peak value.

20. The apparatus according to claim 19, characterized in that, The predetermined ratio is 60%.

21. The apparatus according to claim 12, characterized in that, The characteristic thresholds are determined based on clinical statistical data for each characteristic, and the pulsation amplitude ratio thresholds are determined based on clinical statistical data.

22. The apparatus according to claim 12, characterized in that, The first number of consistent pulses are continuous pulses.

23. A method for processing stored blood pressure data, characterized in that, The blood pressure data is measured and stored during each deflation of the blood pressure cuff, and the blood pressure data includes the cuff pressure value and average pulsation amplitude after each deflation. The method includes: Receive the stored blood pressure data; An average pulsation amplitude curve is generated based on multiple cuff pressure values ​​and multiple average pulsation amplitudes. Calculate the best fitting curve that best fits the average pulsation amplitude curve; At each of the stated cuff pressure values, the deviation between the corresponding average pulsation amplitude and the fitted curve is calculated; Based on the deviation at each of the cuff pressure values, the mean of the deviation is calculated, and the mean of the deviation is compared with a predetermined mean deviation threshold. If the mean of the deviation is greater than the mean deviation threshold, it is determined that the blood pressure storage data has motion artifacts; In response to the determination that the blood pressure storage data has motion artifacts, for each average pulse amplitude exceeding the fitted curve, the positive deviation between the average pulse amplitude and the fitted curve is calculated, and the positive deviation is compared with a predetermined positive deviation threshold. In response to the positive deviation being greater than the positive deviation threshold, the average pulsation amplitude is replaced with the corresponding value on the fitted curve to obtain a modified average pulsation amplitude; and The mean arterial pressure, systolic pressure, and diastolic pressure are calculated using the cuff pressure value and the modified mean pulsation amplitude.

24. The method according to claim 23, characterized in that, The average pulsation amplitude represents the average peak-to-peak amplitude of multiple pulsations in the pressure measurement values ​​obtained by the pressure sensor over time after each deflation of the blood pressure cuff, and The cuff pressure value represents the absolute pressure level of the plurality of pulses.

25. The method according to claim 23, characterized in that, The method further includes calculating the deviation between the corresponding average pulsation amplitude and the fitted curve according to the following formula: Deviation = absolute(mean pulsation amplitude – fitted curve) / mean pulsation amplitude The absolute() operator represents the absolute value operation.

26. The method according to claim 23, characterized in that, The method further includes calculating the positive deviation between the average pulsation amplitude and the fitted curve according to the following formula: Positive deviation = (average pulsation amplitude – fitted curve) / average pulsation amplitude > 0.

27. The method according to claim 23, characterized in that, The method further includes: In response to the mean deviation being less than or equal to the mean deviation threshold, mean arterial pressure, systolic pressure, and diastolic pressure are calculated using the plurality of cuff pressure values ​​and the plurality of average pulse amplitudes in the blood pressure storage data.

28. The method according to claim 23, characterized in that, In the modified average pulsation amplitude, the average pulsation amplitude with zero or negative deviation from the fitted curve, and the average pulsation amplitude with positive deviation less than or equal to the positive deviation threshold, remain unchanged.

29. The method according to claim 23, characterized in that, The deviation from the mean threshold and the positive deviation threshold are each determined based on clinical statistical data.

30. The method according to claim 23, characterized in that, The fitted curve is a Gaussian curve.

31. A device for processing blood pressure storage data, characterized in that, The blood pressure storage data is measured and stored during each deflation of the blood pressure cuff, and the blood pressure storage data includes the cuff pressure value and average pulsation amplitude after each deflation. The device includes: An input unit is used to receive the stored blood pressure data; The processor is configured as follows: An average pulsation amplitude curve is generated based on multiple cuff pressure values ​​and multiple average pulsation amplitudes. Calculate the best fitting curve that best fits the average pulsation amplitude curve; At each of the stated cuff pressure values, the deviation between the corresponding average pulsation amplitude and the fitted curve is calculated; Based on the deviation at each of the cuff pressure values, the mean of the deviation is calculated, and the mean of the deviation is compared with a predetermined mean deviation threshold. If the mean of the deviation is greater than the mean deviation threshold, it is determined that the blood pressure storage data has motion artifacts; In response to the determination that the blood pressure storage data has motion artifacts, for each average pulse amplitude exceeding the fitted curve, the positive deviation between the average pulse amplitude and the fitted curve is calculated, and the positive deviation is compared with a predetermined positive deviation threshold. In response to the positive deviation being greater than the positive deviation threshold, the average pulsation amplitude is replaced with the corresponding value on the fitted curve to obtain a modified average pulsation amplitude; and The mean arterial pressure, systolic pressure, and diastolic pressure are calculated using the cuff pressure value and the modified mean pulsation amplitude.

32. The apparatus according to claim 31, characterized in that, The average pulsation amplitude represents the average peak-to-peak amplitude of multiple pulsations in the pressure measurement values ​​obtained by the pressure sensor over time after each deflation of the blood pressure cuff, and The cuff pressure value represents the absolute pressure level of the plurality of pulses.

33. The apparatus according to claim 31, characterized in that, The processor is also configured to calculate the deviation between the corresponding average pulsation amplitude and the fitted curve according to the following formula: Deviation = absolute(mean pulsation amplitude – fitted curve) / mean pulsation amplitude The absolute() operator represents the absolute value operation.

34. The apparatus according to claim 31, characterized in that, The processor is also configured to calculate the positive deviation between the average pulsation amplitude and the fitted curve according to the following formula: Positive deviation = (average pulsation amplitude – fitted curve) / average pulsation amplitude > 0.

35. The apparatus according to claim 31, characterized in that, The processor is also configured to: In response to the mean deviation being less than or equal to the mean deviation threshold, mean arterial pressure, systolic pressure, and diastolic pressure are calculated using the plurality of cuff pressure values ​​and the plurality of average pulse amplitudes in the blood pressure storage data.

36. The apparatus according to claim 31, characterized in that, In the modified average pulsation amplitude, the average pulsation amplitude with zero or negative deviation from the fitted curve, and the average pulsation amplitude with positive deviation less than or equal to the positive deviation threshold, remain unchanged.

37. The apparatus according to claim 31, characterized in that, The deviation from the mean threshold and the positive deviation threshold are each determined based on clinical statistical data.

38. The apparatus according to claim 31, characterized in that, The fitted curve is a Gaussian curve.

39. A computer-readable storage medium storing instructions that, when executed by a computer, cause the computer to perform the method according to any one of claims 1-11 and 23-30.

40. A computer program product storing instructions that, when executed by a computer, cause the computer to perform the method according to any one of claims 1-11 and 23-30.

41. An external defibrillator monitor, characterized in that, Includes the apparatus according to any one of claims 12-22 and 31-38.

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