Sphygmomanometer for detecting irregular pulse waves and its operating method

Abstract

The present disclosure relates to a blood pressure monitor for determining an irregular pulse wave and an operating method thereof. A blood pressure monitor according to an embodiment of the present disclosure includes a processor that displays an oscillometric signal detected from a subject while an internal pressure of a cuff surrounding a body part of the subject is varied on a display, determines whether an irregular pulse wave is present based on interval information of the oscillometric signal, and, if the irregular pulse wave is present, displays a visual mark on the display for a region of the oscillometric signal that is determined to be the irregular pulse wave.

Description

[Technical Field]

[0001] The following description relates to a blood pressure monitor that determines an irregular pulse wave and its method of operation. [Background technology]

[0002] There are two methods for measuring blood pressure: invasive and non-invasive. While invasive methods are the most accurate, non-invasive methods are the mainstream due to concerns about pain and infection. Non-invasive methods are divided into auscultation and oscillometric methods, both of which use a cuff. Auscultation involves listening to sound energy generated by turbulence that occurs during the movement of blood flow due to the opening and closing of blood vessels, using a stethoscope. The oscillometric method, which is mainly used in blood pressure monitors, is less accurate than auscultation.

[0003] Arrhythmia is an important measurement item for measuring cardiac function, and is widely used in health checkups to detect changes in blood pressure. Regular pulse waves are generated by the contraction of the cardiac muscle, but when pulse waves do not occur regularly, but rather disappear or occur irregularly, this is called arrhythmia. Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention provides a blood pressure monitor and method for detecting an irregular pulse wave using an oscillometric signal and determining whether the irregular pulse wave is due to arrhythmia.

[0005] The present invention provides a blood pressure monitor and method that simultaneously displays an oscillometric signal and Kortkoff sounds, and provides visual marks in areas of the oscillometric signal and Kortkoff sounds where irregular pulse waves occur.

[0006] However, the technical issues are not limited to those described above, and other technical issues may exist. [Means for solving the problem]

[0007] A blood pressure monitor according to an embodiment of the present disclosure may include a processor that displays an oscillometric signal detected from a subject while an internal pressure of a cuff surrounding a body part of the subject is varied, determines whether an irregular pulse wave is present based on interval information of the oscillometric signal, and, if the irregular pulse wave is present, displays a visual mark on the display for a region of the oscillometric signal that is determined to be the irregular pulse wave.

[0008] The processor can display on the display, together with the oscillometric signal, Kortkoff sounds contained in a sound signal collected by a microphone while the internal pressure of the cuff is varied, and can display the visual mark in an area of ​​the Kortkoff sounds corresponding to an area in the oscillometric signal that is determined to be the irregular pulse wave.

[0009] The processor may obtain the interval information based on a period corresponding to a peak interval or a valley interval of the oscillometric signal.

[0010] The processor may obtain the interval information based on a period corresponding to a peak interval or a valley interval of a graph obtained by differentiating the oscillometric signal.

[0011] The processor can determine that the irregular pulse wave is present when any of the periods deviates from the average value of the periods by a threshold or more.

[0012] The processor determines a baseline for the peak value or valley value of the oscillometric signal, and if there is a section where the peak value or the valley value deviates from the baseline by more than a threshold, it does not determine whether the irregular pulse wave exists for that section.

[0013] When the irregular pulse wave is present, the processor can determine whether the irregular pulse wave is due to arrhythmia, and if so, display an alarm on the display.

[0014] The processor may input the interval information into a machine learning model for determining atrial fibrillation to determine whether the irregular pulse wave is due to atrial fibrillation among the arrhythmias.

[0015] The processor may input the interval information into a machine learning model for determining premature contractions to determine whether the irregular pulse wave is due to the premature contraction of the arrhythmia.

[0016] A blood pressure monitor according to an embodiment of the present disclosure may include a processor that displays an oscillometric signal detected from a subject while an internal pressure of a cuff surrounding a body part of the subject is varied on a display, determines whether or not an irregular pulse wave is present based on interval information of the oscillometric signal, and, if the irregular pulse wave is present, determines whether or not the irregular pulse wave is due to arrhythmia and displays an alarm on the display.

[0017] A method of operating a blood pressure monitor according to an embodiment of the present disclosure may include an operation of detecting an oscillometric signal from a subject while an internal pressure of a cuff surrounding a body part of the subject is varied, and displaying the detected signal on a display; an operation of determining whether an irregular pulse wave is present based on interval information of the oscillometric signal; and an operation of displaying a visual mark on the display for a region of the oscillometric signal determined to be the irregular pulse wave, if the irregular pulse wave is present.

[0018] The method may further include an operation of displaying Kortkoff sounds included in a sound signal collected by a microphone while the internal pressure of the cuff is varied, together with the oscillometric signal, on the display, and the operation of displaying the visual mark on the display may display the visual mark in an area of ​​the Kortkoff sounds corresponding to an area determined to be the irregular pulse wave in the oscillometric signal.

[0019] The method may further include obtaining the interval information based on a period corresponding to a peak interval or a valley interval of the oscillometric signal.

[0020] The method may further include obtaining the interval information based on a period corresponding to a peak interval or a valley interval of a graph obtained by differentiating the oscillometric signal.

[0021] The operation of determining whether or not an irregular pulse wave exists can determine that the irregular pulse wave exists if there is a cycle among the cycles that deviates from the average value of the cycles by more than or less than a threshold value.

[0022] The operation of determining whether or not an irregular pulse wave exists involves determining a reference line for the peak value or valley value of the oscillometric signal, and if there is a section where the peak value or the valley value deviates from the reference line by more than a threshold value, the operation of determining whether or not an irregular pulse wave exists for that section is not performed.

[0023] The method may further include an operation of determining, if the irregular pulse wave is present, whether the irregular pulse wave is due to arrhythmia, and, if the irregular pulse wave is due to arrhythmia, displaying an alarm on the display.

[0024] The operation of determining whether the irregular pulse wave is due to arrhythmia can be performed by inputting the interval information into a machine learning model for determining atrial fibrillation to determine whether the irregular pulse wave is due to atrial fibrillation among the arrhythmias.

[0025] The operation of determining whether the irregular pulse wave is due to arrhythmia can be performed by inputting the interval information into a machine learning model that determines premature contractions to determine whether the irregular pulse wave is due to the premature contractions of the arrhythmia.

[0026] A blood pressure monitor according to one embodiment of the present disclosure may include a processor that synchronizes and displays on a display two or more of an oscillometric signal detected from a subject while the internal pressure of a cuff surrounding a body part of the subject is varied, Kortkoff sounds contained in a sound signal collected by a microphone while the internal pressure of the cuff is varied, and an electrocardiogram measured from the subject while the internal pressure of the cuff is varied. [Effects of the Invention]

[0027] According to an embodiment of the present invention, there is provided a blood pressure monitor and method that utilizes interval information of an oscillometric signal to determine irregular pulse waves and arrhythmias and provide health information to a subject.

[0028] According to one embodiment of the present invention, a blood pressure monitor and method can be provided that displays visual marks in areas of the oscillometric signal and Kortkoff sounds where irregular pulse waves have occurred, allowing a subject to intuitively recognize the occurrence of irregular pulse waves. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 is a diagram illustrating a blood pressure monitor according to an embodiment of the present invention. [Figure 2] FIG. 2 is a flowchart illustrating a method of operating the sphygmomanometer according to one embodiment of the present invention. [Figure 3] 3a and 3b are diagrams illustrating signals detected from a subject according to an embodiment of the present invention. [Figure 4] 4 and 5 are diagrams for explaining interval information of an oscillometric signal according to one embodiment of the present invention. [Figure 5] 4 and 5 are diagrams for explaining interval information of an oscillometric signal according to one embodiment of the present invention. [Figure 6] 6a and 6b are diagrams illustrating measurement errors according to one embodiment of the present invention. [Figure 7] 7a and 7b are diagrams for explaining the display of an irregular pulse wave detected in a signal detected from a subject according to one embodiment of the present invention. [Figure 8] FIG. 8 is a flowchart illustrating a method of operating the sphygmomanometer according to one embodiment of the present invention. [Figure 9] FIG. 9 is a diagram showing a blood pressure monitor according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, the scope of the patent application is not limited to or restricted by such embodiments. The same reference numerals shown in each drawing indicate the same elements.

[0031] Various modifications may be made to the embodiments described below, and the embodiments described below are not intended to be limited to the embodiments, but should be understood to include all modifications, equivalents, or alternatives thereto.

[0032] Although terms such as "first" or "second" may be used to describe multiple components, such terms should be construed only to distinguish one component from the other components. For example, a first component may be designated as a second component, and similarly, a second component may be designated as a first component.

[0033] The terms used in the embodiments are merely used to describe particular embodiments and are not intended to limit the embodiments. A singular expression includes a plural expression unless the context clearly dictates otherwise. In this specification, phrases such as "A or B," "at least one of A and B," "at least one of A or B," "A, B or C," "at least one of A, B and C," and "at least one of A, B, or C" may include any one of the items listed with the phrase or all possible combinations thereof. In this specification, terms such as "comprise" or "have" indicate the presence of a feature, numeral, step, operation, component, part, or combination thereof described in the specification, and should be understood as not precluding the presence or addition of one or more other features, numerals, steps, operations, components, parts, or combinations thereof.

[0034] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art. Commonly used, predefined terms should be interpreted as having a meaning consistent with the meaning they have in the context of the relevant art, and should not be interpreted as having an ideal or overly formal meaning unless expressly defined herein.

[0035] In addition, when describing the present embodiment with reference to the drawings, the same reference numerals will be used to refer to the same components regardless of the reference numerals, and redundant descriptions thereof will be omitted. In the description of the present embodiment, if a detailed description of related prior art is determined to unnecessarily obscure the gist of the embodiment, the detailed description thereof will be omitted.

[0036] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0037] FIG. 1 is a diagram illustrating a blood pressure monitor according to an embodiment of the present invention.

[0038] Referring to FIG. 1, a blood pressure monitor 100 includes a processor (not shown), a display 110 and an input unit 120 .

[0039] The processor controls the overall operation of the sphygmomanometer 100 and may control other components included in the sphygmomanometer 100 .

[0040] The display 110 displays the blood pressure measurement process and results. For example, the display 110 may display in real time a signal detected from the subject 150 while the internal pressure of the cuff 130 surrounding a body part of the subject 150 is varied. The display 110 may also display blood pressure information of the subject 150 once the blood pressure measurement is completed. In addition, the display 110 may display various information related to the blood pressure measurement without limitation.

[0041] The input unit 120 may receive inputs related to blood pressure measurement from the subject 150 and / or the examiner. For example, the input unit 120 may receive inputs such as starting the operation of the sphygmomanometer 100, stopping it in an emergency, outputting measured blood pressure information, or outputting pre-stored blood pressure information, but is not limited to the above examples. In FIG. 1, the input unit 120 is illustrated as a physical button for convenience of explanation, but is not limited to the above examples and may be implemented in various forms (e.g., touch, a jog dial, a switch, etc.). In another embodiment, the input unit 120 may be omitted, and inputs may be received from the subject 150 and / or the examiner via the display 110 embodied as a touch screen.

[0042] The cuff 130 includes an airbag whose internal pressure is adjusted by injecting or discharging a fluid, and the airbag can surround a body part of the subject 150 during blood pressure measurement. For example, the body part of the subject 150 may be the upper arm, but is not limited to the above example. In this specification, the internal pressure of the airbag in the cuff 130 will be referred to as the internal pressure of the cuff 130 for convenience of explanation.

[0043] The connection line 140 includes an electric wire and a fluid tube that connect the sphygmomanometer 100 and the cuff 130. The electric wire can electrically connect a sensor (e.g., a microphone, a pressure sensor, etc.) in the cuff 130 to the sphygmomanometer 100. The fluid tube can transmit fluid injected into an airbag in the cuff 130 and fluid discharged from the airbag.

[0044] The sphygmomanometer 100 can micro-collect a sound signal generated when the cuff 130 is inflated to a pressure equal to or greater than the normal systolic blood pressure and then gradually deflated while the cuff 130 is wrapped around the upper arm of the subject 150, and detect an oscillometric signal using a pressure sensor. The sphygmomanometer 100 can detect Korotkoff sounds from the sound signal by analyzing the sound signal and the oscillometric signal, and can determine the systolic blood pressure and diastolic blood pressure of the subject 150 in real time based on the detected Korotkoff sounds. The sphygmomanometer 100 also displays the detected Korotkoff sounds on the display 110 in real time. When the reference Korotkoff sounds corresponding to the systolic blood pressure and the reference Korotkoff sounds corresponding to the diastolic blood pressure are displayed on the display 110 in real time, the corresponding reference Korotkoff sounds may be visually displayed differently, or a visual mark (e.g., an arrow, a triangle, etc.) indicating the corresponding reference Korotkoff sounds may be displayed.

[0045] In this way, when Kortkoff sounds detected while the cuff 130 is being depressurized are displayed in real time on the display 110, information about the systolic blood pressure and the diastolic blood pressure are also displayed in real time on the display 110, thereby efficiently improving the reliability of the subject 150 in the measured blood pressure. The subject 150 can visually confirm the Kortkoff sounds detected in real time, and can also visually confirm the systolic blood pressure corresponding to the start time of the Kortkoff sounds and the diastolic blood pressure corresponding to the end time of the Kortkoff sounds, thereby improving the reliability of the subject 150 in the measurement results of the sphygmomanometer 100.

[0046] According to one embodiment, the sphygmomanometer 100 can combine the advantages of the auscultation method and the oscillometric method by using characteristics of Kortkoff sounds and oscillometric signals (e.g., the relationship between Kortkoff sounds and the oscillometric signal). The sphygmomanometer 100 may detect the oscillometric signal. The sphygmomanometer 100 may determine whether Kortkoff sounds are detected in a section based on a peak of the oscillometric signal and whether the amplitude of the Kortkoff sounds is equal to or greater than a predetermined threshold amplitude. If a Kortkoff sound equal to or greater than the predetermined threshold amplitude is detected in a section based on the peak of the oscillometric signal, the sphygmomanometer 100 determines whether the Kortkoff sounds are noise through frequency analysis of the Kortkoff sounds. If the Kortkoff sounds are determined not to be noise, the sphygmomanometer 100 may display the Kortkoff sounds on the display 110 in real time.

[0047] FIG. 2 is a flowchart illustrating a method of operating the sphygmomanometer according to one embodiment of the present invention.

[0048] Hereinafter, the operations in the embodiments may be performed in order, but are not necessarily performed in order. For example, the order of the operations may be changed, or at least two operations may be performed in parallel. The operations shown in FIG. 2 may be performed by at least one component of the blood pressure monitor.

[0049] In operation 210, the blood pressure monitor detects an oscillometric signal from the subject.

[0050] The blood pressure monitor detects an oscillometric signal from the subject while varying the internal pressure of a cuff surrounding a body part of the subject. The blood pressure monitor may also detect Kortkoff sounds simultaneously with detecting the oscillometric signal. The blood pressure monitor can display the oscillometric signal and the Kortkoff sounds on a display in real time.

[0051] In operation 220, the blood pressure monitor obtains interval information based on the oscillometric signal.

[0052] After completing the blood pressure measurement, the blood pressure monitor can obtain interval information based on the oscillometric signal. The interval information is information about the interval (i.e., period) from the peak of the nth signal to the peak of the n+1th signal of the oscillometric signal. The interval information is information about the interval (i.e., period) from the valley to the valley from the nth signal to the n+1th signal of the oscillometric signal. The interval information will be further described with reference to FIG. 4.

[0053] In operation 230, the blood pressure monitor determines whether an irregular pulse wave is present based on the interval information.

[0054] The blood pressure monitor may use the interval information to calculate an average value of the interval information. If there is a period that deviates from the average value of the interval information by more than a threshold, the blood pressure monitor determines that an irregular pulse wave is present.

[0055] In operation 240, the blood pressure monitor determines whether the irregular pulse wave is due to arrhythmia.

[0056] When an irregular pulse wave is detected, the blood pressure monitor can determine whether the irregular pulse wave is due to arrhythmia. Specifically, the blood pressure monitor can input interval information indicating the presence of an irregular pulse wave into a machine learning model to determine whether the irregular pulse wave is due to arrhythmia. The machine learning model may be trained to determine whether the irregular pulse wave is due to arrhythmia when the interval information is input. The machine learning model may be a deep neural network (DNN), a convolutional neural network (CNN), and / or a recurrent neural network (RNN), etc.

[0057] The following describes the oscillometric signal and Kortkoff sounds displayed together on the tip-leaf of the sphygmomanometer.

[0058] 3a and 3b are diagrams illustrating signals detected from a subject according to an embodiment of the present invention.

[0059] Referring to FIG. 3a, an oscillometric signal 310, a pressure signal 320, and Kortkoff sounds 330 are shown.

[0060] The oscillometric signal 310 can be detected from the pressure signal 320. The oscillometric signal 310 may be extracted via a filter that extracts the oscillometric signal 310 from the pressure signal 320.

[0061] The pressure signal 320 is a signal related to the pressure inside the cuff. After pressure is applied to the air bag inside the cuff to measure the subject's blood pressure, the pressure gradually decreases. Here, the isocardial pressure generated by the contraction of the heart is transmitted to the upper arm. Therefore, the isocardial pressure is transmitted to the air bag of the cuff wrapped around the upper arm. The pressure signal 320 is a signal related to the pressure inside the cuff and the isocardial pressure. Therefore, although the pressure signal 320 appears to be a straight line, it may fluctuate due to the isocardial pressure.

[0062] The Kortkoff sounds 330 are signals used in auscultation. Auscultation can determine blood pressure based on the Kortkoff sounds 330 generated when the cuff is inflated and then deflated. For example, the point at which the Kortkoff sounds 330 begin to appear when the cuff is deflated is the systolic blood pressure (SBP), and the point at which the Kortkoff sounds 330 cease to appear and disappear can be determined as the diastolic blood pressure (DBP). The systolic blood pressure is the systolic blood pressure 340, and the diastolic blood pressure is the diastolic blood pressure 350. Referring to FIG. 3a, the subject's systolic blood pressure 340 is 134 mmHg, and the diastolic blood pressure 350 is 88 mmHg. The Kortkoff sounds 330 are not collected only between the systolic blood pressure 340 and the diastolic blood pressure 350.

[0063] On the other hand, unlike the Kortkoff sounds 330, the oscillometric signal 310 can be detected outside the range between the systolic blood pressure 340 and the diastolic blood pressure 350. Therefore, in this document, any one of the oscillometric signals 310 outside the range between the systolic blood pressure 340 and the diastolic blood pressure 350 can also be used to obtain interval information. This is because if interval information is obtained only in the range between the systolic blood pressure 340 and the diastolic blood pressure 350, there will be too few samples.

[0064] Referring to Figure 3b, a display is shown that further displays an electrocardiogram (ECG) 360 according to one embodiment of the present disclosure. The oscillometric signal 310, pressure signal 320, Kortkoff sounds 330, systolic blood pressure 340, and diastolic blood pressure 350 of Figure 3b are the same as those described above with reference to Figure 3a, and therefore will not be described in further detail.

[0065] The sphygmomanometer may simultaneously display two or more of the oscillometric signal 310, Kortkoff sounds 330, and electrocardiogram 360. For example, referring to Figure 3b, the sphygmomanometer may simultaneously display the oscillometric signal 310, Kortkoff sounds 330, and electrocardiogram 360. The sphygmomanometer may also display two or more of the oscillometric signal 310, Kortkoff sounds 330, and electrocardiogram 360 on a display in real time.

[0066] Here, the oscillometric signal 310, the Kortkoff sounds 330, and the electrocardiogram 360 can be synchronized and displayed on a display. For example, a blood pressure monitor may display the oscillometric signal 310, the Kortkoff sounds 330, and the electrocardiogram 360 measured at the same time side by side on a display.

[0067] In other words, the blood pressure monitor may display on a display two or more of the oscillometric signal 310 detected from the subject while the internal pressure of the cuff surrounding the subject's body part is varied, the Kortkoff sounds 330 included in the sound signal collected by the microphone while the internal pressure of the cuff is varied, and the electrocardiogram 36 measured from the subject while the internal pressure of the cuff is varied. The two or more signals displayed on the display may be displayed based on the same time axis.

[0068] According to one embodiment, the blood pressure monitor may receive an electrocardiogram 360 measured while the internal pressure of the cuff is varied from a separate electrocardiogram measuring device and display it on a display. Also, according to one embodiment, the blood pressure monitor may measure an electrocardiogram 360 while the internal pressure of the cuff is varied and display it on a display.

[0069] Since irregular pulse waves are most strongly correlated with electrocardiogram 360, electrocardiogram 360 can be used to verify irregular pulse waves determined by the sphygmomanometer using oscillometric signal 310.

[0070] The interval information of the oscillometric signals detected from the subject will be described below.

[0071] 4 and 5 are diagrams for explaining interval information of an oscillometric signal according to one embodiment of the present invention.

[0072] Referring to FIG. 4, there is shown a first graph 410 displaying only the oscillometric signal and a second graph 420 displaying the peak interval of the oscillometric signal.

[0073] The blood pressure monitor can acquire interval information from the time when the magnitude of the oscillometric signal exceeds the threshold. Therefore, the oscillometric signal 411 shown in the first graph 410 is the oscillometric signal 411 displayed after the magnitude exceeds the threshold. Here, the threshold is referred to as a first threshold to distinguish it from a threshold for determining an irregular pulse wave, which will be described below.

[0074] Referring to a first graph 410, there is shown an oscillometric signal 411. In order to use the oscillometric signal 411 to determine whether an irregular pulse wave is present, interval information of the oscillometric signal 411 is required.

[0075] The interval information of the oscillometric signal 411 is the period (i.e., peak interval) that is the time from when a peak 413 of one of the oscillometric signals 411 occurs until when a peak 415 of the next signal occurs. The interval information of the oscillometric signal 411 is the period (i.e., valley interval) that is the time from when a valley 417 of one of the oscillometric signals 411 occurs until when a valley 419 of the next signal occurs.

[0076] In this document, the blood pressure monitor can determine whether an irregular pulse wave exists in the oscillometric signal 411 based on the peak interval or the valley interval. Therefore, the magnitude of the peak or the valley is not taken into consideration when determining whether an irregular pulse wave exists.

[0077] Referring to the second graph 420, the peak interval is shown. The second graph 420 is the peak interval of the oscillometric signal 411 shown in the first graph 410. Therefore, each point shown in the second graph 420 represents the period from when one signal peak occurred until when the next signal peak occurred. For example, the first point 421 represents that it took 0.48 seconds from when one signal peak occurred until when the next signal peak occurred.

[0078] The sphygmomanometer determines whether an irregular pulse wave exists based on interval information (i.e., peak interval or valley interval) of the oscillometric signal 411. The sphygmomanometer calculates the average value of the periods included in the interval information. If any one of the periods deviates from the average value by more than a threshold, the sphygmomanometer determines that an irregular pulse wave exists. Here, the threshold can be called a second threshold to distinguish it from the first threshold for the magnitude of the oscillometric signal described above.

[0079] For example, referring to second graph 420, the average value of the period may be 0.4 seconds. If the threshold is assumed to be 25%, the blood pressure monitor can determine whether an irregular pulse wave exists based on whether there is a period that deviates from 0.3 seconds to 0.5 seconds, which is ±25% of 0.4 seconds. Therefore, because second point 423, third point 425, and fourth point 427 deviate from each other by 0.3 seconds to 0.5 seconds, the blood pressure monitor can determine that an irregular pulse wave exists.

[0080] The threshold value used as a criterion for determining whether an irregular pulse wave exists may be determined in various ways. For example, the threshold value may be set differently depending on age and / or gender.

[0081] It will be obvious to those skilled in the art that the above description of the method for determining an irregular pulse wave using the peak interval can be applied equally to the valley interval, and therefore, the description of the method for determining an irregular pulse wave using the valley interval will be omitted.

[0082] 5, there are shown an oscillometric signal 510, and graphs 520 and 530 obtained by differentiating the oscillometric signal. In FIG. 4 described above, the period between maximum values ​​540 (i.e., peaks) of the oscillometric signal 510 was used to determine whether or not an irregular pulse wave exists.

[0083] The most accurate method for determining whether an irregular pulse wave exists is to use an electrocardiogram, which is a record of the electrical activity of the heart during a cardiac cycle. Specifically, the RR interval of the electrocardiogram is used to determine whether an irregular pulse wave exists.

[0084] Graph 530 is a graph comparing the RR interval of the electrocardiogram with the peak interval of the oscillometric signal 510. Referring to graph 530, it can be seen that the RR interval of the electrocardiogram and the peak interval of the oscillometric signal 510 are similar.

[0085] Cardiac contractions are highly correlated with electrocardiograms. The oscillometric signals 510 are detected after the heart contracts with respect to a heartbeat. Therefore, any one of the oscillometric signals 510 is detected later than any one of the corresponding electrocardiogram signals. The maximum differential value 550 of the oscillometric signal occurs before the maximum value 540 of the oscillometric signal, as this is the moment when the oscillometric signal increases most rapidly. Referring to the oscillometric signals 510, it can be seen that the maximum differential value 550 of the oscillometric signal occurs earlier in time than the maximum value 540 of the oscillometric signal for any one of the signals. Consequently, the time when the maximum differential value 550 of the oscillometric signal occurs is adjacent to the time when the peak of the electrocardiogram (i.e., the R of the QRS complex) occurs, compared to the time when the maximum value 540 of the oscillometric signal occurs.

[0086] Therefore, the peak intervals of graph 520 obtained by differentiating the oscillometric signal are more similar to the RR intervals of an electrocardiogram than the peak intervals of oscillometric signal 510. Therefore, the blood pressure monitor can determine whether an irregular pulse wave is present more accurately when using the peak intervals or valley intervals of graph 520 obtained by differentiating the oscillometric signal than when using the peak intervals or valley intervals of oscillometric signal 510.

[0087] Therefore, as described with reference to Fig. 4, the blood pressure monitor can determine whether an irregular pulse wave exists using not only oscillometric signal 510 but also graph 520 obtained by differentiating the oscillometric signal. The method for determining whether an irregular pulse wave exists using the peak interval or valley interval of graph 520 obtained by differentiating the oscillometric signal is the same as that for oscillometric signal 510, and therefore a description thereof will be omitted.

[0088] 6a and 6b are diagrams illustrating measurement errors according to one embodiment of the present invention.

[0089] Referring to FIG. 6a, similar to FIG. 3a, an oscillometric signal 610 and Kortkoff sounds 620 are shown.

[0090] When detecting the oscillometric signal 610 from the subject, noise can cause the oscillometric signal 610 to be inaccurately collected. For example, if the subject moves while detecting the oscillometric signal 610, the oscillometric signal 610 may contain noise. When a blood pressure monitor uses the noisy oscillometric signal 610 to determine whether an irregular pulse wave is present, the noise can cause an error in determining that a noise exists even when there is no actual irregular pulse wave. Therefore, to prevent this error, the noise portion must be removed from the noisy oscillometric signal 610 to determine whether an irregular pulse wave is present, or the oscillometric signal must be measured again.

[0091] A method for determining whether noise has occurred due to the subject's movements or the like will be described below.

[0092] Referring to the oscillometric signal 610, the shape of the graph in the middle part is different from the shapes of the immediately preceding and following sections, which indicates that noise was generated during blood pressure measurement due to the subject's movements.

[0093] The blood pressure monitor may use the magnitude of the signal (e.g., peak value and / or valley value) to determine whether noise has occurred, unlike the method of determining whether an irregular pulse wave exists. That is, the blood pressure monitor may determine a baseline for the peak value or valley value of the oscillometric signal 610. If there is a section where the peak value or valley value deviates from the baseline by more than a threshold, the blood pressure monitor cannot determine whether a pulse wave exists for that section.

[0094] Alternatively, if there is a section where the peak or valley value deviates from the baseline by more than a threshold value, the blood pressure monitor may remeasure the blood pressure. Here, the threshold value may be referred to as a third threshold value in order to distinguish it from the first and second threshold values ​​described above.

[0095] The reference line may be determined based on various criteria. According to one embodiment, the reference line for the peak value may be determined based on n peak values ​​(n is a natural number) that occurred before the peak value 630 of the signal to be determined. The reference line for the peak value is the average of the n peak values ​​(n is a natural number) that occurred before the peak value 630 of the signal to be determined. Therefore, if the peak value 630 of the signal to be determined deviates from the average of the n peak values ​​by more than a third threshold, the sphygmomanometer can determine that the section including the peak value 630 of the signal to be determined is a section including noise.

[0096] According to one embodiment, the reference line for the peak value may be a kind of trend line. The sphygmomanometer may obtain interval information from the peak value of the oscillometric signal 610 that exceeds a first threshold. Here, the sphygmomanometer may generate a peak value trend line from the peak value of the oscillometric signal 610 that exceeds the first threshold. If the peak value 630 of the signal to be determined deviates from the trend line by a third threshold or more, the sphygmomanometer may determine that the section including the peak value 630 of the signal to be determined is a section including noise.

[0097] It will be obvious to those skilled in the art that the above-described method of determining a reference line for a peak value and determining whether there is a section where the peak value deviates from the reference line by more than the third threshold value can be applied to a valley value as well. Therefore, a description of the method of determining a reference line for a valley value and determining whether there is a section where the valley value deviates from the reference line by more than the third threshold value will be omitted.

[0098] 6b, which illustrates a display further displaying an electrocardiogram 640 according to an embodiment of the present disclosure, the matters described above with reference to FIG. 3b may be applied to the display of the electrocardiogram 640, and therefore a more detailed description will be omitted. The matters described above with reference to FIG. 6a may be applied to the oscillometric signal 610, Kortkoff sounds 620, and signal peak values ​​630 of FIG. 6b, and therefore a more detailed description will be omitted.

[0099] As described above, the section containing signal peak value 630 is a section in which noise occurs due to the subject's movement during blood pressure measurement. Observing electrocardiogram 640, it can be seen that the signal in the section corresponding to the section containing signal peak value 630 fluctuates more than the other signals. This is because the noise is due to the subject's movement during blood pressure measurement. However, the interval information of electrocardiogram 640 remains unchanged.

[0100] The following describes the operation of the blood pressure monitor when it is determined that an irregular pulse wave is present in the oscillometric signal.

[0101] 7a and 7b are diagrams for explaining the display of an irregular pulse wave detected in a signal detected from a subject according to one embodiment of the present invention.

[0102] Referring to FIG. 7a, an oscillometric signal 710 and Kortkoff sounds 720 are shown. The oscillometric signal 710 is a signal determined to have an irregular pulse wave present.

[0103] In other words, the oscillometric signal 710 is determined to have an irregular pulse wave based on interval information. The oscillometric signal 710 is determined to have a period that deviates from the average period by more than a second threshold value among periods corresponding to peak intervals or valley intervals. Alternatively, the oscillometric signal 710 is determined to have a period that deviates from the average period by more than a second threshold value among periods corresponding to peak intervals or valley intervals in a graph obtained by differentiating the oscillometric signal 710.

[0104] The sphygmomanometer displays a visual mark 730 in the area determined to be an irregular pulse wave. By displaying the visual mark 730 in the area determined to be an irregular pulse wave, the subject can intuitively recognize that an irregular pulse wave has occurred. According to one embodiment, the sphygmomanometer may display the oscillometric signal 710 and Kortkoff sounds 720 included in the area determined to be an irregular pulse wave as a bold line, in another color, or by flashing. Therefore, the box display in the area determined to be an irregular pulse wave in FIG. 7a is merely an example of a visual mark, and the present disclosure is not limited thereto.

[0105] Additionally, according to one embodiment, the sphygmomanometer may display, as a single visual mark, areas of the oscillometric signal 710 and the Kortkoff sounds 720 that are determined to be irregular pulse waves. For example, the sphygmomanometer may display, as a single integrated visual mark, areas of the oscillometric signal 710 and the Kortkoff sounds 720 that are determined to be irregular pulse waves.

[0106] The blood pressure monitor may also display visual marks 730 in areas of the oscillometric signal 710 that are determined to be irregular pulse waves, and visual marks 740 in areas of the corresponding Kortkoff sounds 720. The visual marks 730 in the oscillometric signal 710 and the visual marks 740 in the Kortkoff sounds 720 may be the same or different.

[0107] The oscillometric signal 710 and the Kortkoff sounds 720 may be signals detected simultaneously during the same time. Therefore, in Figure 7a, the oscillometric signal 710 and the Kortkoff sounds 720 are simply arranged one above the other for visual convenience and may share the same x-axis (time axis). Therefore, the oscillometric signal 710 and the Kortkoff sounds 720 correspond to each other during the same time period.

[0108] Therefore, it is confirmed that an irregular pulse wave has also occurred in the region of Kortkoff sounds 720 corresponding to the region determined as an irregular pulse wave in the oscillometric signal 710.

[0109] Furthermore, when the blood pressure monitor determines that an irregular pulse wave is present in the oscillometric signal 710, it can determine whether the irregular pulse wave is due to arrhythmia. When the blood pressure monitor determines that an irregular pulse wave is present in the oscillometric signal 710, it can input interval information to a machine learning model for determining atrial fibrillation and a machine learning model for determining premature contractions. The machine learning model for determining atrial fibrillation is a machine learning model trained by various known methods, and can determine whether the irregular pulse wave is due to atrial fibrillation when it receives interval information from the oscillometric signal 710 in which an irregular pulse wave occurs. Similarly, the machine learning model for determining premature contractions is a machine learning model trained by various known methods, and can determine whether the irregular pulse wave is due to premature contractions when it receives interval information from the oscillometric signal 710 in which an irregular pulse wave occurs. Here, premature contractions include all of ventricular premature contractions, atrial premature contractions, and ventricular / atrial premature contractions.

[0110] The blood pressure monitor may display an alarm in addition to the visual marks 730, 740 if the irregular pulse wave is due to premature contractions and / or atrial fibrillation, which are arrhythmias. The blood pressure monitor may also notify the subject via the alarm that an irregular pulse wave has occurred and suggest medical treatment if the irregular pulse wave is suspected to be due to arrhythmia. Therefore, the blood pressure monitor can assist the subject in detecting arrhythmia early.

[0111] 7b illustrates a display further displaying an electrocardiogram 750 according to an embodiment of the present disclosure. The oscillometric signal 710, Kortkoff sounds 720, and visual marks 730 and 740 have been described above, and therefore will not be described again. Furthermore, the display of the electrocardiogram 750 may be similar to that described above with reference to FIG. 3b, and therefore will not be described in further detail.

[0112] The blood pressure monitor may further display an electrocardiogram 750. By detecting the area of ​​the electrocardiogram 750 corresponding to the area determined as an irregular pulse wave in the oscillometric signal 710, it is possible to confirm that one cycle has been skipped. That is, by referring to the electrocardiogram 750, the blood pressure monitor can verify whether the area determined as an irregular pulse wave in the oscillometric signal 710 actually corresponds to an irregular pulse wave.

[0113] If an irregular pulse wave does not exist in a region of the electrocardiogram 750 corresponding to a region determined as an irregular pulse wave in the oscillometric signal 710, the sphygmomanometer does not determine that region as having an irregular pulse wave. Conversely, if an irregular pulse wave exists in a region of the electrocardiogram 750 corresponding to a region not determined as having an irregular pulse wave in the oscillometric signal 710, the sphygmomanometer determines that region as having an irregular pulse wave.

[0114] When the blood pressure monitor further displays an electrocardiogram 750, it may further display a visual mark 760 in a region of the electrocardiogram 750 that corresponds to a region determined to be an irregular pulse wave in the oscillometric signal 710. The above description of the visual marks 750 and 760 can be applied to the visual mark 760 as is, and therefore the description thereof will be omitted.

[0115] FIG. 8 is a flowchart illustrating a method of operating the sphygmomanometer according to one embodiment of the present invention.

[0116] In the following embodiments, the operations may be performed in order, but are not necessarily performed in that order. For example, the order of the operations may be changed, or at least two operations may be performed in parallel. The operations shown in FIG. 2 may be performed by at least one component of the blood pressure monitor.

[0117] In operation 810, the blood pressure monitor detects an oscillometric signal from the subject while varying the internal pressure of a cuff surrounding the subject's body part.

[0118] In operation 820, the blood pressure monitor determines whether an irregular pulse wave is present based on the interval information of the oscillometric signal.

[0119] The blood pressure monitor determines a reference line for the peak or valley value of the oscillometric signal, and if there is a section where the peak or valley value deviates from the reference line by more than a threshold value, it is unable to determine whether an irregular pulse wave exists in the section.

[0120] In operation 830, the blood pressure monitor displays a visual mark on the display for areas of the oscillometric signal that are determined to have irregular pulse waves, if any.

[0121] The blood pressure monitor may obtain interval information based on a period corresponding to a peak interval or a valley interval of the oscillometric signal.

[0122] The blood pressure monitor may acquire interval information based on a period corresponding to a peak interval or a valley interval of a graph obtained by differentiating the oscillometric signal.

[0123] The blood pressure monitor may determine that an irregular pulse wave is present when any of the cycles deviates from the average value of the cycles by more than or less than a threshold value.

[0124] When an irregular pulse wave is present, the blood pressure monitor determines whether the irregular pulse wave is due to arrhythmia. If the irregular pulse wave is due to arrhythmia, the blood pressure monitor may display an alarm on a display.

[0125] The blood pressure monitor may input the interval information into a machine learning model for determining atrial fibrillation, and determine whether the irregular pulse wave is due to atrial fibrillation, a type of arrhythmia.

[0126] The blood pressure monitor may input the interval information into a machine learning model for determining premature contractions to determine whether the irregular pulse wave is due to a premature contraction of arrhythmia.

[0127] The blood pressure monitor may display Kortkoff sounds contained in the sound signal collected by the microphone while the internal pressure of the cuff is varied, together with the oscillometric signal, on a display. The blood pressure monitor may display a visual mark in the area of ​​the Kortkoff sounds corresponding to an area determined to be an irregular pulse wave in the oscillometric signal.

[0128] 1 to 7b can be applied to each operation shown in FIG. 8, and therefore a more detailed description will be omitted.

[0129] FIG. 9 is a diagram showing a blood pressure monitor according to one embodiment of the present invention.

[0130] 9, a blood pressure monitor 900 includes a processor 910. The blood pressure monitor 900 may further include a display 920 and a memory 930. The processor 910, the display 920, and the memory 930 can communicate with each other via a bus, a Peripheral Component Interconnect Express (PCIe), and / or a Network on a Chip (NoC), etc.

[0131] The processor 910 displays on a display an oscillometric signal detected from the subject while the internal pressure of the cuff surrounding the subject's body part is varied, determines whether or not an irregular pulse wave is present based on interval information of the oscillometric signal, and, if an irregular pulse wave is present, displays on the display a visual mark for the area of ​​the oscillometric signal that is determined to be an irregular pulse wave.

[0132] The processor 910 can display the Kortkoff sounds contained in the sound signal collected by the microphone while the internal pressure of the cuff is varied on a display together with the oscillometric signal, and can display visual marks for areas of the Kortkoff sounds that correspond to areas in the oscillometric signal that are determined to be irregular pulse waves.

[0133] The processor 910 can obtain the interval information based on a period corresponding to a peak interval or a valley interval of the oscillometric signal.

[0134] The processor 910 can obtain interval information based on a period corresponding to a peak interval or a valley interval of a graph obtained by differentiating the oscillometric signal.

[0135] If any of the periods deviates from the average period by more than a threshold value, the processor 910 can determine that an irregular pulse wave is present.

[0136] The processor 910 determines a baseline for the peak or valley value of the oscillometric signal, and if there is a section where the peak or valley value deviates from the baseline by more than a threshold, it cannot determine whether an irregular pulse wave exists for the section.

[0137] If an irregular pulse wave is present, the processor 910 can determine whether the irregular pulse wave is due to arrhythmia, and if so, can display an alarm on the display.

[0138] The processor 910 can input the interval information into a machine learning model for determining atrial fibrillation to determine whether the irregular pulse waves are due to atrial fibrillation, an arrhythmia.

[0139] The processor 910 can input the interval information into a machine learning model for determining premature contractions to determine whether the irregular pulse wave is due to a premature contraction of the arrhythmia.

[0140] The processor 910 displays on a display an oscillometric signal detected from the subject while the internal pressure of the cuff surrounding the subject's body part is varied, determines whether or not an irregular pulse wave is present based on the interval information of the oscillometric signal, and if an irregular pulse wave is present, determines whether or not the irregular pulse wave is due to arrhythmia and displays an alarm on the display.

[0141] The display 920 can display in real time the oscillometric signal and Kortkoff sounds detected from the subject while the internal pressure of the cuff surrounding the subject's body part is varied under the control of the processor 910. The display 920 can display visual marks in areas of the oscillometric signal and Kortkoff sounds where irregular pulse waves are present.

[0142] The memory 930 may include computer-readable instructions, and the processor 910 may perform the operations described above by executing the instructions stored in the memory 930. The memory 930 may be a volatile memory or a non-volatile memory.

[0143] Additionally, the blood pressure monitor 900 can process the operations described above.

[0144] Meanwhile, the method according to the present invention can be implemented in various recording media such as magnetic storage media, optically readable media, and digital storage media by being written as a program that can be executed by a computer.

[0145] Implementations of the various techniques described herein may be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or combinations thereof. Implementations may also be implemented as a computer program product, i.e., a computer program tangibly embodied in an information carrier, such as a machine-readable storage device or a radio signal, for processing by or controlling the operation of a data processing device, e.g., a programmable processor, a computer, or multiple computers. Computer programs, such as those described above, may be written in any form of programming language, including compiled or interleaved languages, and may be deployed in any form, including as a stand-alone program or as modules, components, subroutines, or other distinct units suitable for use in a computing environment. Computer programs may be deployed to be processed on one computer or multiple computers at one site, or distributed across multiple sites and interconnected by a communications network.

[0146] Processors suitable for running a computer program include, by way of example, both general-purpose and special-purpose microprocessors, and any one or more processors of any kind of digital computer. Typically, a processor will receive instructions and data from a read-only memory or a random-access memory, or both. Elements of a computer may include at least one processor for executing instructions and one or more memory devices for storing instructions and data. Typically, a computer will include one or more mass storage devices, such as magnetic, magneto-optical, or optical disks, for storing data, and may be coupled to receive data from, transmit data to, or both. Suitable information carriers for embodying computer program instructions and data include, by way of example, semiconductor memory devices, magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CD-ROMs (Compact Disk Read Only Memory) and DVDs (Digital Video Disks), magneto-optical media such as floppy disks, read-only memory (ROM), random access memory (RAM), flash memory, erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), etc. The processor and memory may be supplemented by or included in special purpose logic circuitry.

[0147] Furthermore, the computer-readable recording medium may be any available medium that can be accessed by a computer and includes both computer storage media and transmission media.

[0148] While the present specification contains details of several specific implementations, these should not be construed as limitations on any invention or the scope of the claims, but rather as descriptions of features specific to particular embodiments of particular inventions. Certain features described herein in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented in multiple embodiments individually or in any suitable subcombination. Furthermore, although features may be depicted as operating in a particular combination and initially claimed therewith, one or more features from a claimed combination may, in some cases, be excluded from that combination, and the claimed combination may be modified into a subcombination or a variation of that subcombination.

[0149] Similarly, although acts are depicted in the figures in a particular order, this should not be understood as implying that such acts should be performed in the particular order shown, or in the sequential order shown, to obtain preferred results, or that all of the shown acts must be performed. In certain cases, multitasking and parallel processing may be advantageous. Also, the separation of various apparatus components in the above-described embodiments should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and apparatus may generally be integrated together in a single software product or packaged in multiple software products.

[0150] Meanwhile, the embodiments of the present invention disclosed in this specification and the drawings are merely specific examples presented to aid in understanding and are not intended to limit the scope of the present invention. It is obvious to those skilled in the art to which the present invention pertains that various modifications based on the technical idea of ​​the present invention can be implemented in addition to the embodiments disclosed in this specification.

Claims

1. 1. A blood pressure monitor comprising: a processor that displays on a display an oscillometric signal detected from a subject while an internal pressure of a cuff surrounding a body part of the subject is varied; determines whether or not an irregular pulse wave is present based on interval information of the oscillometric signal; and, if the irregular pulse wave is present, displays on the display a visual mark for a region of the oscillometric signal that is determined to be the irregular pulse wave.

2. 2. The blood pressure monitor of claim 1, wherein the processor displays Kortkoff sounds included in a sound signal collected by a microphone while the internal pressure of the cuff is varied, together with the oscillometric signal, on the display, and displays the visual mark in a region of the Kortkoff sounds corresponding to a region of the oscillometric signal determined to be the irregular pulse wave.

3. The blood pressure monitor according to claim 1 , wherein the processor acquires the interval information based on a period corresponding to a peak interval or a valley interval of the oscillometric signal.

4. The blood pressure monitor according to claim 1 , wherein the processor acquires the interval information based on a period corresponding to a peak interval or a valley interval of a graph obtained by differentiating the oscillometric signal.

5. The blood pressure monitor according to claim 3 , wherein the processor determines that the irregular pulse wave is present when any of the periods deviates from an average value of the periods by a threshold or more.

6. 2. The blood pressure monitor of claim 1, wherein the processor determines a reference line for a peak value or a valley value of the oscillometric signal, and if there is a section where the peak value or the valley value deviates from the reference line by more than a threshold value, the processor does not determine whether the irregular pulse wave exists for the section.

7. 2. The blood pressure monitor of claim 1, wherein the processor, when the irregular pulse wave is present, determines whether the irregular pulse wave is due to arrhythmia, and if the irregular pulse wave is due to arrhythmia, displays an alarm on the display.

8. 8. The blood pressure monitor of claim 7, wherein the processor inputs the interval information into a machine learning model for determining atrial fibrillation to determine whether the irregular pulse wave is due to the atrial fibrillation of the arrhythmia.

9. 8. The blood pressure monitor of claim 7, wherein the processor inputs the interval information into a machine learning model for determining premature contractions to determine whether the irregular pulse wave is due to the premature contraction of the arrhythmia.

10. A blood pressure monitor comprising: a processor that displays on a display an oscillometric signal detected from a subject while an internal pressure of a cuff surrounding a body part of the subject is varied; determines whether or not an irregular pulse wave is present based on interval information of the oscillometric signal; and, if the irregular pulse wave is present, determines whether or not the irregular pulse wave is due to arrhythmia and displays an alarm on the display.

11. detecting an oscillometric signal from the subject while the internal pressure of a cuff surrounding the subject's body part is varied and displaying the signal on a display; determining whether or not an irregular pulse wave exists based on interval information of the oscillometric signal; If the irregular pulse wave is present, displaying a visual mark on the display for a region of the oscillometric signal that is determined to be the irregular pulse wave; A method of operating a blood pressure monitor, including:

12. The method further includes an operation of displaying Kortkoff sounds included in a sound signal collected by a microphone while the internal pressure of the cuff is varied, together with the oscillometric signal, on the display; 12. The method of claim 11, wherein the act of displaying the visual mark on the display displays the visual mark in an area of ​​the Kortkoff sound corresponding to an area of ​​the oscillometric signal determined to be the irregular pulse wave.

13. The method of claim 11 , further comprising obtaining the interval information based on a period corresponding to a peak interval or a valley interval of the oscillometric signal.

14. The method of claim 11 , further comprising: acquiring the interval information based on a period corresponding to a peak interval or a valley interval of a graph obtained by differentiating the oscillometric signal.

15. 15. The method according to claim 13, wherein the operation of determining whether or not an irregular pulse wave is present comprises determining that the irregular pulse wave is present when any of the periods deviates from an average value of the periods by a threshold value or more.

16. 12. The method of claim 11, wherein the operation of determining whether or not an irregular pulse wave exists comprises determining a reference line for peak values ​​or valley values ​​of the oscillometric signal, and if there is a section in which the peak value or the valley value deviates from the reference line by more than a threshold, not determining whether or not the irregular pulse wave exists for the section.

17. If the irregular pulse wave is present, determining whether the irregular pulse wave is due to arrhythmia; If the arrhythmia is caused, an operation of displaying an alarm on the display; The method of claim 11 further comprising:

18. 18. The method of claim 17, wherein the operation of determining whether the irregular pulse wave is due to arrhythmia comprises inputting the interval information into a machine learning model for determining atrial fibrillation to determine whether the irregular pulse wave is due to atrial fibrillation of the arrhythmia.

19. 18. The method of claim 17, wherein the operation of determining whether the irregular pulse wave is due to arrhythmia comprises inputting the interval information into a machine learning model for determining premature contractions to determine whether the irregular pulse wave is due to the premature contraction of the arrhythmia.

20. A blood pressure monitor comprising a processor that synchronizes and displays on a display two or more of an oscillometric signal detected from a subject while an internal pressure of a cuff surrounding a body part of the subject is varied, Kortkoff sounds contained in a sound signal collected by a microphone while the internal pressure of the cuff is varied, and an electrocardiogram measured from the subject while the internal pressure of the cuff is varied.

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