JP2015154884A - Ultrasonic measurement apparatus and ultrasonic measurement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To propose a new technique which can perform non-pressurized and continuous blood pressure monitoring.

SOLUTION: An ultrasonic measurement apparatus 1 determines the blood pressure state (normal/abnormal) of a subject 2 in a non-pressurized state on the basis of the variation in a blood vessel diameter for one heartbeat period of the subject 2 calculated by using an ultrasonic wave, namely calculates the similarity between a waveform for determination indicating the variation in the blood vessel diameter for one heartbeat period and each of a plurality of reference waveforms associated with the blood pressure state in advance, and determines the blood pressure state corresponding to the reference waveform with the maximum similarity as the determination result. The blood vessel diameter has substantially the same variation as the blood pressure, and two peaks due to an ejection wave and a reflection wave of the ejection wave appear in the waveform indicating the variation in the blood vessel diameter at the normal time as well as the blood pressure. With this, the waveform having the two peaks with the normal blood pressure state and the waveform having only one peak with the abnormal blood pressure state are prepared as the reference waveforms.

COPYRIGHT: (C)2015,JPO&INPIT

Description

  The present invention relates to an ultrasonic measurement apparatus that measures a blood vessel diameter using ultrasonic waves.

  In the artificial dialysis treatment, blood pressure is regularly measured for the purpose of monitoring a rapid decrease in blood pressure of a patient. A cuff type sphygmomanometer is generally used as the sphygmomanometer. The cuff-type sphygmomanometer is a pressurization type blood pressure measurement that measures blood pressure by pressing a blood vessel with a cuff wound around the upper arm, for example. Pressurization of the patient's blood vessels could have an impact on blood removal and return during artificial dialysis. In addition, the pressurization type blood pressure measurement is not suitable for the purpose of immediately detecting the occurrence of a decrease in blood pressure during dialysis treatment, because continuous measurement is impossible in principle. Thus, as a technique that is non-pressurized and capable of continuous blood pressure measurement, a technique is known in which a pulse wave is detected by a photoelectric sensor and blood pressure is estimated from the detected pulse wave (see, for example, Patent Document 1). ).

JP 11-89801 A

  However, in the method of estimating blood pressure from the pulse wave detected by the photoelectric sensor as in the technique of Patent Document 1 described above, the estimation accuracy may be low. Therefore, there is a high possibility that measurement with a cuff-type sphygmomanometer is required after all.

  The present invention has been made in view of the above circumstances, and its object is to propose a new technique that enables continuous blood pressure monitoring without pressure.

  A first embodiment for solving the above-described problem includes a blood vessel diameter measuring unit that measures a blood vessel diameter using ultrasonic waves, and blood pressure abnormality based on the measured change in blood vessel diameter for at least one heartbeat period. And a determination unit that determines a blood pressure state.

  Further, as another form, measuring a blood vessel diameter by ultrasonic waves, and determining a blood pressure state including a blood pressure abnormality based on the measured change in blood vessel diameter for at least one heartbeat period, You may comprise the ultrasonic measurement method containing.

  According to the first embodiment and the like, the blood vessel diameter is measured by non-pressurized and non-invasive ultrasonic waves, and the blood pressure state including abnormal blood pressure is determined based on the fluctuation of the blood vessel diameter for one heartbeat period. . Since there is no need for pressurization, continuous blood pressure monitoring is possible.

  Further, as a second form, the ultrasonic measurement apparatus according to the first form, wherein the determination unit is configured to determine a blood pressure state using a blood vessel diameter peak in one heartbeat period. You may do it.

  According to the second embodiment, the blood pressure state is determined using the blood vessel diameter peak in one heartbeat period. Since the blood vessel repeatedly contracts and expands isotropically with the pulsation of the heart, the blood vessel diameter fluctuates substantially the same as the blood pressure. That is, a peak due to the ejection wave and the reflected wave of the ejection wave appears in the waveform indicating the fluctuation of the blood vessel diameter at the normal time, like the blood pressure. Therefore, it is possible to determine whether or not the blood pressure state is normal by determining the peak included in the blood vessel diameter in one measured heartbeat period.

  Further, as a third aspect, in the ultrasonic measurement apparatus according to the second aspect, the determination unit determines the blood pressure state using the number of peaks or the value of the peaks in one heartbeat period. A sound wave measuring device may be configured.

  According to the third aspect, the blood pressure state is determined using the number of peaks or the peak value in one heartbeat period. As described above, at normal times, two peaks resulting from the ejection wave and the reflected wave of the ejection wave appear in the waveform indicating the fluctuation of the blood vessel diameter during one heartbeat period. Therefore, it is possible to determine whether or not the blood pressure state is normal by determining the number of peaks in the waveform of the measured blood vessel diameter.

  Further, as a fourth form, in the ultrasonic measurement apparatus according to the second or third form, the determination unit includes the peak corresponding to the ejection wave and the peak corresponding to the reflected wave in one heartbeat period. You may comprise the ultrasonic measuring device which determines a blood-pressure state using ratio with a peak.

  According to the fourth aspect, the blood pressure state is determined using the ratio of the peaks corresponding to the ejection wave and the reflected wave in one heartbeat period.

  Further, as a fifth aspect, in the ultrasonic measurement apparatus according to the first aspect, the determination unit associates a measured waveform indicating a blood vessel diameter variation for one measured heartbeat period with a blood pressure state. An ultrasound measurement apparatus may be configured that calculates the degree of similarity with each of the plurality of reference waveforms obtained, and determines the blood pressure state based on the calculated degree of similarity.

  According to the fifth aspect, the blood pressure state is determined based on the similarity between the measurement waveform indicating the blood vessel fluctuation for one heartbeat period and each of the plurality of reference waveforms associated with the blood pressure state. That is, the waveforms can be compared, and for example, the blood pressure state corresponding to the reference waveform having the highest similarity can be used as the determination result.

  Further, as a sixth form, the ultrasonic measurement apparatus according to the fifth form, wherein the measurement waveform when the blood pressure state is determined to be normal by the determination unit is used as the new reference waveform corresponding to the normal state An ultrasonic measurement device further including a reference waveform setting unit may be configured.

  According to the sixth embodiment, the measurement waveform when the blood pressure state is determined to be normal is a new reference waveform corresponding to the normal state. As a result, the reference waveform corresponding to the normal state to be compared increases, so that it can be determined with higher accuracy whether or not the blood pressure state is normal.

  Further, as a seventh aspect, the ultrasonic measurement apparatus according to the first aspect further includes a change amount calculation unit that calculates a change amount in one heartbeat period of the measured blood vessel diameter, and the determination unit includes: An ultrasonic measurement device that determines a blood pressure state based on the calculated amount of change may be configured.

  According to the seventh embodiment, the blood pressure state is determined based on the change amount in one heartbeat period of the blood vessel diameter. It is known that the amount of change in blood vessel diameter during one heartbeat period increases as blood pressure decreases. For this reason, it is possible to determine a decrease in blood pressure (low blood pressure) based on the change amount of the blood vessel diameter.

  Further, as an eighth aspect, the ultrasonic measurement apparatus according to any one of the first to seventh aspects, wherein the determination unit is configured to determine that the blood pressure abnormality is low blood pressure as the blood pressure abnormality. Also good.

  According to the eighth embodiment, it is determined that the blood pressure is abnormal as a blood pressure abnormality. That is, for example, it is possible to continuously monitor and detect a decrease in blood pressure, which is the main purpose of blood pressure monitoring during artificial dialysis treatment.

Application example of an ultrasonic measurement device. Explanatory drawing of the measurement of the blood vessel diameter using an ultrasonic wave. An example of the waveform which shows the fluctuation | variation of the blood vessel diameter in case a blood-pressure state is normal. An example of the waveform which shows the fluctuation | variation of the blood vessel diameter in case a blood-pressure state is abnormal (low blood pressure). Explanatory drawing of the comparison with the waveform of the measured blood vessel diameter, and a reference | standard waveform. Explanatory drawing of determination of the blood-pressure state based on a comparison with a reference waveform. The function block diagram of an ultrasonic measuring device. The data structural example of reference | standard waveform data. The flowchart of a blood-pressure monitoring process. An additional explanatory view of a reference waveform whose blood pressure state is normal. Explanatory drawing of the determination of the blood-pressure state based on a peak number and a peak value. Explanatory drawing of the determination of the blood-pressure state based on the fluctuation amount of the blood vessel diameter. Explanatory drawing of the determination of the blood-pressure state based on the expansion speed of the blood vessel. Explanatory drawing of the determination of the blood pressure state based on the variation | change_quantity in a blood vessel diameter.

[overall structure]
FIG. 1 is a diagram illustrating an application example of the ultrasonic measurement apparatus 1 in the present embodiment. The ultrasonic measurement apparatus 1 according to the present embodiment is an apparatus that monitors the blood pressure state of a subject (dialysis patient) 1 using ultrasonic waves, assuming use during dialysis treatment. A sonic probe 20.

  The ultrasonic probe 20 includes an ultrasonic sensor 22 (see FIG. 2) that transmits and receives an ultrasonic pulse signal or burst signal of several MHz to several tens of MHz, and outputs a reception signal to the main body device 10. For example, the ultrasonic probe 20 is attached to the neck of the subject 2 so that the ultrasonic sensor 22 is positioned immediately above the carotid artery. Here, “directly above” means an operation manual meaning when operating the ultrasonic sensor 22. To be precise, the carotid artery is positioned on the ultrasonic irradiation line irradiated by the ultrasonic sensor 22. It is a positional relationship to do.

  The main body device 10 is wired to the ultrasonic probe 20 and monitors the blood pressure state of the subject 2 using the ultrasonic probe 20. Specifically, the ultrasonic wave is irradiated to the blood vessel (carotid artery) of the subject 2 using the ultrasonic probe 20, the blood vessel diameter is measured based on the received signal of the reflected wave, and the measured blood vessel diameter is also measured. And the blood pressure state of the subject 2 is detected. The main body device 10 is configured to be able to transmit and receive data with the dialysis device 30 by wireless communication or the like.

  The dialysis device 30 is a device that circulates the blood of the subject 2 through the blood circuit tube and performs hemodialysis. While monitoring the blood pressure state of the subject 2 detected by the ultrasonic measurement device 1, Perform dialysis treatment. During dialysis treatment, blood pressure may change over time, and when it changes, blood pressure tends to decrease. Therefore, at least whether or not the blood pressure state of the subject 2 is a low blood pressure state is monitored by the ultrasonic measurement device 1.

[principle]
(A) Measurement of blood vessel diameter First, measurement of a blood vessel diameter using ultrasonic waves will be described. FIG. 2 is a view for explaining the measurement of the blood vessel diameter, and shows a cross section along the longitudinal direction of the blood vessel 4. The ultrasonic probe 20 is affixed to the neck of the subject 2 so that the ultrasonic sensor 22 is in close contact with the skin surface 3 immediately above the blood vessel (carotid artery) 4.

  Ultrasonic waves are transmitted from the ultrasonic sensor 22 in the downward direction in FIG. The ultrasonic waves are reflected at portions having different acoustic impedances. That is, a part of the ultrasonic wave transmitted from the ultrasonic sensor 22 is reflected by the front wall 4 a and the rear wall 4 b of the blood vessel as viewed from the ultrasonic sensor 22, and the reflected wave is received by the ultrasonic sensor 22. The And the blood vessel diameter D is calculated | required from the time difference of the reflected wave from the front wall 4a, and the reflected wave from the rear wall 4b, and the transmission speed of an ultrasonic wave.

(B) Measurement Wave of Blood Vessel Diameter A blood vessel repeatedly contracts and expands isotropically with the pulsation of the heart. That is, the blood vessel diameter varies substantially the same as the blood pressure.

  FIG. 3 is a schematic waveform showing the fluctuation of the blood vessel diameter D during one heartbeat period. In FIG. 3, the horizontal direction is time t, and the vertical direction is the blood vessel diameter D. When normal, two peaks appear in the blood vessel diameter waveform in one heartbeat period. One heartbeat period is composed of a systole and a diastole. That is, in the systole, the blood pressure rises due to the ejection wave being sent out from the heart, and the blood vessel diameter increases accordingly. And the 1st peak P1 by an ejection wave appears. After that, after the blood vessel diameter is slightly reduced, the diameter is expanded again, and a second peak P2 due to the reflected wave appears. Thereafter, the blood vessel diameter gradually decreases.

  As shown in FIG. 3A, the two peaks P1 and P2 are usually larger in the first peak P1 due to the ejection wave. However, as shown in FIG. 3B, the second peak P2 may appear larger.

  By the way, when blood pressure is abnormal, such as an abnormal drop in blood pressure (low blood pressure), it is known that one peak disappears and only one peak P appears in the blood vessel diameter waveform as shown in FIG. Yes. FIG. 4 is a schematic waveform showing the fluctuation of the blood vessel diameter at the time of low blood pressure. The horizontal direction is time t, and the vertical direction is the blood vessel diameter D. As shown in FIG. 4, the fluctuation of the blood vessel diameter at the time of low blood pressure is generally gentle and appears as a generally dull waveform. This is presumably because when the blood pressure is lowered, the internal pressure of the blood vessel is lowered, so that the blood vessel expansion and contraction operations are reduced.

(C) Determination of Blood Pressure State In the present embodiment, the blood pressure state of the subject 2 is determined by comparing the measured waveform of the blood vessel diameter with a reference waveform prepared in advance in association with the blood pressure state.

  In the present embodiment, there are two types of blood pressure states, “normal” and “abnormal”. The normal blood pressure state is a state in which the blood pressure can be regarded as being in a normal range (for example, about 90 to 120 [mmHg]). A typical example of the reference waveform corresponding to the normal blood pressure state is a waveform having two peaks in one heartbeat period as shown in FIG. 3, for example.

  Further, the abnormal blood pressure state is a state where the blood pressure is abnormally reduced as compared to normal (a state of low blood pressure). A typical example of the reference waveform corresponding to this abnormal blood pressure state is a waveform having only one peak in one heartbeat period as shown in FIG.

  A plurality of reference waveforms are prepared for each blood pressure state (normal / abnormal). In addition, these reference waveforms are, for example, waveforms that indicate fluctuations in blood vessel diameter actually measured using ultrasonic waves, and are actually measured using a conventional cuff type sphygmomanometer (pressurized sphygmomanometer) or the like. A waveform corresponding to a blood pressure state determined from the blood pressure is generated and prepared.

  In comparison with the reference waveform, first, as shown in FIG. 5, a waveform for one heartbeat period is extracted from the measurement waveform of the blood vessel diameter to obtain a measurement waveform. In this embodiment, one heartbeat period is from the start time of the systole, that is, from the time when the blood vessel diameter corresponding to the minimum blood pressure is minimum to the time when the blood vessel diameter is next minimum.

  Next, the measurement waveform and the reference waveform are compared, but the heart rate is not constant but varies depending on the situation, that is, the length of one heartbeat period (one heartbeat time) is not constant. May have different lengths. For this reason, one waveform is enlarged or reduced along the time axis direction so that one heartbeat time of both waveforms (measurement waveform and basic waveform) coincide. Then, a correlation calculation is performed on the determination waveform and the reference waveform in which the lengths of one heartbeat period are matched, and the similarity (correlation value) is calculated.

  The similarity is calculated for a plurality of reference waveforms as shown in FIG. Then, a reference waveform that maximizes the calculated similarity is selected, and the blood pressure state determined in the selected reference waveform is set as the determination result of the blood pressure state of the subject 2. As a result, when it is determined that there is an abnormality (blood pressure drop), a predetermined alarm operation (notification operation) such as output of a predetermined alarm sound, display of an alarm message, lighting of an alarm lamp is performed, Inform.

[Function configuration]
FIG. 7 is a diagram illustrating a functional configuration of the ultrasonic measurement apparatus 1. According to FIG. 7, the ultrasonic measurement apparatus 1 includes an operation input unit 110, a display unit 120, a sound output unit 130, a communication unit 140, a processing unit 200, and a storage unit 300. .

  The operation input unit 110 is realized by an input device such as a button switch, a touch panel, or various sensors, and outputs an operation signal corresponding to the performed operation to the processing unit 200. The display unit 120 is realized by a display device such as an LCD (Liquid Crystal Display), and performs various displays according to display signals from the processing unit 200.

  The sound output unit 130 is realized by a sound output device such as a speaker, and outputs various sounds based on the sound signal from the processing unit 200. The communication unit 130 is realized by a wireless communication device such as a wireless local area network (LAN) or Bluetooth (registered trademark), and performs communication with an external device (mainly the dialysis device 30).

  The processing unit 200 is realized by electronic components such as a microprocessor such as a CPU (Central Processing Unit) and a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), and an IC (Integrated Circuit) memory. Various operations are executed based on programs and data stored in the processing unit 200, operation signals from the operation input unit 110, and the like, and the operation of the ultrasonic measurement apparatus 1 is controlled. The processing unit 200 includes an ultrasonic measurement control unit 210, a blood vessel diameter calculation unit 220, a determination waveform generation unit 230, a similarity calculation unit 240, and a blood pressure state determination unit 250, and a blood pressure monitoring program The blood pressure monitoring process according to 312 (see FIG. 9) is executed.

  The ultrasonic measurement control unit 210 controls transmission / reception of ultrasonic waves in the ultrasonic probe 20. Specifically, ultrasonic waves are transmitted from the ultrasonic probe 20 at a transmission timing of a predetermined period. Further, the ultrasonic probe 20 amplifies the signal of the reflected wave of the ultrasonic wave received. The ultrasonic measurement control unit 210 can also be referred to as a functional unit that acquires a reception signal of ultrasonic reflected waves (measurement data using ultrasonic waves). The measurement data can be displayed as various image data such as A mode, B mode, and M mode.

  The blood vessel diameter calculation unit 220 calculates the blood vessel diameter of the subject 2 based on the reception signal of the ultrasonic wave reflected by the ultrasonic probe 20. That is, the reception of the reflected wave from each of the front wall and the rear wall of the blood vessel 4 is determined from the reception intensity of the reception signal. Then, the blood vessel diameter is calculated from the time difference between the reception times of the respective reflected waves. As a technique for discriminating the front wall and the rear wall from the reception signal of the reflected ultrasonic wave and calculating the blood vessel diameter, a known technique can be used as appropriate.

  In addition, the calculation of the blood vessel diameter is repeatedly executed at predetermined time intervals (for example, a time interval that can be said to be almost real time such as 10 ms), because the ultrasonic probe 20 transmits the ultrasonic waves and receives the reflected waves as needed. . Thereby, the waveform which shows the fluctuation | variation of the blood vessel diameter is obtained. The blood vessel diameter calculated by the blood vessel diameter calculating unit 220 is stored and stored as measured blood vessel diameter data 330 in association with the measurement time.

  The determination waveform generation unit 230 generates a determination waveform from the blood vessel diameter calculated by the blood vessel diameter calculation unit 220. That is, the waveform portion for one heartbeat period is extracted from the waveform indicating the fluctuation of the blood vessel diameter to obtain a determination waveform. In the present embodiment, the period from the time when the blood vessel diameter becomes the minimum to the time when the next blood vessel diameter becomes the first is set as one heartbeat period. The determination waveform generated by the determination waveform generation unit 230 is stored as determination waveform data 340.

  The similarity calculation unit 240 calculates the similarity between the determination waveform generated by the determination waveform generation unit 230 and each of the plurality of reference waveforms. First, one waveform (for example, the reference waveform) is enlarged or reduced in the time axis direction so that the length of one heartbeat period of the determination waveform and the reference waveform are matched. Next, a correlation value, that is, a similarity is calculated by performing a correlation operation between the determination waveform and the reference waveform.

  The reference waveform is stored as reference waveform data 320. FIG. 8 is a diagram illustrating an example of a data configuration of the reference waveform data 320. The reference waveform data 320 stores blood vessel diameter waveform data 321 of one heartbeat period, a corresponding blood pressure state 322, and a heartbeat period 323 of the waveform.

  The blood pressure state determination unit 250 determines the blood pressure state based on the similarity calculated by the similarity calculation unit 240. That is, the reference waveform that maximizes the similarity is selected from the similarities between the measurement waveform and the reference waveform, and the blood pressure state 322 defined in the selected reference waveform is used as the determination result. The determination result by the blood pressure state determination unit 250 is accumulated and stored as the blood pressure state determination result data 350 in association with the measurement time, for example.

  The storage unit 300 is realized by a storage device such as a ROM, a RAM, and a hard disk. The storage unit 300 stores programs and data for the processing unit 200 to control the ultrasonic measurement apparatus 1 in an integrated manner, and the processing unit 200 performs operations. It is used as an area and temporarily stores the calculation results executed by the processing unit 200, operation data from the operation input unit 110, and the like. In the present embodiment, the storage unit 300 includes a system program 310, a blood pressure monitoring program 312, reference waveform data 320, measurement blood vessel diameter data 330, determination waveform data 340, and blood pressure state determination result data 350. Remembered.

[Process flow]
FIG. 9 is a flowchart illustrating the flow of blood pressure monitoring processing. This process is realized by the processing unit 200 executing a process according to the blood pressure monitoring program 312.

  First, the blood vessel diameter calculation unit 220 causes the ultrasonic probe 20 to start transmitting and receiving ultrasonic waves, and starts calculating the blood vessel diameter (step S1). Next, the determination waveform generation unit 230 extracts the calculated blood vessel diameter in one heartbeat period, and generates a determination waveform (step S3).

  Subsequently, the similarity calculation unit 240 expands or contracts in the time axis direction so that one heartbeat period coincides with the determination waveform for each reference waveform (step S5). Then, for each reference waveform, a correlation calculation with the determination waveform is performed to calculate the similarity (step S7).

  Thereafter, the blood pressure state determination unit 250 selects a reference waveform with the maximum similarity (step S9), and determines the blood pressure state associated with the selected reference waveform as the blood pressure state of the subject 2 ( Step S11). As a result, if the determined blood pressure state is normal (step S13: NO), the process returns to step S3 and the same processing is repeated. On the other hand, if the determined blood pressure state is abnormal (step S13: YES), a predetermined alarm output such as outputting an alarm sound or displaying an alarm message is performed (step S15), and the process ends.

[Function and effect]
As described above, according to the ultrasonic measurement apparatus 1 of the present embodiment, non-pressurization and non-invasive treatment are performed based on the change in the blood vessel diameter for one heartbeat period of the subject 2 measured using ultrasonic waves. The blood pressure state (normal / abnormal) of the examiner 2 can be determined.

  That is, the degree of similarity between the determination waveform indicating the fluctuation of the blood vessel diameter during one heartbeat period and each of a plurality of reference waveforms previously associated with the blood pressure state is calculated, and the blood pressure corresponding to the reference waveform having the maximum similarity The state is the determination result. The blood vessel diameter has substantially the same fluctuation as blood pressure, and the waveform showing the fluctuation of the blood vessel diameter at normal time has two peaks due to the ejection wave and the reflected wave of this ejection wave, as with blood pressure. Is normal. For this reason, as the reference waveform, a waveform having two peaks in which the blood pressure state is normal and a waveform having only one peak in which the blood pressure state is abnormal are prepared.

[Modification]
It should be noted that embodiments to which the present invention can be applied are not limited to the above-described embodiments, and can of course be changed as appropriate without departing from the spirit of the present invention.

(A) Addition of Reference Waveform For example, as shown in FIG. 10, a determination waveform in which the blood pressure state is determined to be normal is added to the reference waveform data 320 as a new reference waveform in which the blood pressure state is normal. It may be used for determination.

(B) Number of peaks and peak value As a method for determining the blood pressure state for the determination waveform, the number of peaks or the peak value may be used.

  Specifically, as shown in FIG. 11 (1), when the blood pressure state is normal, two peaks P1 and P2 usually appear in the waveform indicating the fluctuation of the blood vessel diameter in one heartbeat period. Further, as shown in FIG. 11 (2), when the blood pressure state is abnormal (low blood pressure), there is usually only one peak P that appears in the waveform indicating the blood vessel diameter fluctuation in one heartbeat period. In addition, the difference between the values of the two peaks P1 and P2 that appear in a normal blood pressure state is rarely large. Therefore, as shown in FIG. 11 (3), the blood pressure state is determined based on the number of peaks in one heartbeat period and the peak value. That is, when the number of peaks is one, the blood pressure state is determined to be abnormal. On the other hand, when there are two peaks, the blood pressure state is normal when the ratio (= D1 / D2) of the peak values D1 and D2 of the two peaks P1 and P2 is within a predetermined range that can be regarded as substantially equivalent conditions. If it is not within a predetermined range that can be said to be substantially equivalent, the condition is determined to be abnormal.

(C) Amount of change in blood vessel diameter It is known that when blood pressure decreases, the amount of fluctuation in blood vessel diameter increases. For this reason, the blood pressure state is determined by comparing the fluctuation amount of the blood vessel diameter with a predetermined threshold. Specifically, as shown in FIG. 13, a blood vessel diameter fluctuation amount ΔD (maximum value Dmax−minimum value Dmin) in one heartbeat period is obtained, and when the fluctuation amount ΔD is equal to or greater than a predetermined threshold, Abnormality is determined as the state.

(D) Vascular dilation speed It is also known that the dilation speed of the blood vessel differs between when the blood pressure is normal and when it is abnormal. For this reason, the blood pressure state is determined by comparing the blood vessel expansion rate with a predetermined threshold. Specifically, as shown in FIG. 13, an expansion speed (change speed) V is calculated by differentiating a waveform portion in a period Δt in which the blood vessel diameter expands (increases) in one heartbeat period. The blood pressure state is determined based on whether V is equal to or greater than a predetermined threshold. Alternatively, the dilation speed V may be calculated as a change amount (= ΔD / Δt) of the vascular diameter per unit time in the period Δt in which the vascular diameter D dilates (increases) in one heartbeat period.

(E) Change in blood vessel diameter It is also known that the blood vessel diameter decreases as the blood pressure decreases. For this reason, the blood pressure state is determined by comparing the diastolic blood vessel diameter with a predetermined threshold. Specifically, as shown in FIG. 14, for example, a diastolic blood vessel diameter d0 at the start of blood vessel diameter measurement is used as a reference, and a predetermined ratio (for example, 80%) of the diastolic blood vessel diameter d0 is set as a threshold value. When the diastolic blood vessel diameter d is equal to or smaller than this threshold, it is determined that the blood pressure state is abnormal (low blood pressure).

(F) Blood pressure state In the present embodiment, the blood pressure state is two types of normal / abnormal, but may be three or more types. For example, as the third type of blood pressure state, for example, “attention required” that is between normal and abnormal is determined. As a reference waveform in the case where the blood pressure state needs attention, a waveform in which two peaks appear in one heartbeat period but is a dull peak (for example, a waveform in which the fluctuation amount of the blood vessel diameter is a predetermined value or less). What should I do? Then, when the blood pressure state determination results in more than a predetermined number of cautions, it is regarded as an abnormality and an alarm is output.

DESCRIPTION OF SYMBOLS 1 Ultrasonic measurement apparatus, 10 Main body apparatus, 110 Operation input part, 120 Display part, 130 Sound output part, 140 Communication part, 200 Processing part, 210 Ultrasonic measurement control part, 220 Blood vessel diameter calculation part, 230 Waveform generation for determination Unit, 240 similarity calculation unit, 250 blood pressure state determination unit, 300 storage unit, 310 system program, 312 blood pressure monitoring program, 320 reference waveform data, 330 measurement blood vessel diameter data, 340 determination waveform data, 350 blood pressure state determination result data , 20 Ultrasonic probe, 22 Ultrasonic sensor, 30 Dialysis machine 2 Subject (dialysis patient)

Claims (9)

A blood vessel diameter measuring unit for measuring a blood vessel diameter by ultrasonic;
A determination unit for determining a blood pressure state including a blood pressure abnormality based on the measured change in blood vessel diameter for at least one heartbeat period;
An ultrasonic measurement device. The determination unit determines a blood pressure state using a blood vessel diameter peak in one heartbeat period.
The ultrasonic measurement apparatus according to claim 1. The determination unit determines a blood pressure state using the number of peaks or the value of the peaks in one heartbeat period.
The ultrasonic measurement apparatus according to claim 2. The determination unit determines a blood pressure state using a ratio between the peak corresponding to the ejection wave and the peak corresponding to the reflected wave in one heartbeat period.
The ultrasonic measurement apparatus according to claim 2. The determination unit calculates a similarity between the measured waveform indicating the change in blood vessel diameter for one heartbeat period and each of a plurality of reference waveforms associated with a blood pressure state. Based on the blood pressure state,
The ultrasonic measurement apparatus according to claim 1. A reference waveform setting unit that sets the measurement waveform when the blood pressure state is determined to be normal by the determination unit as a new reference waveform corresponding to the normal state;
The ultrasonic measurement apparatus according to claim 5, further comprising: A change amount calculation unit for calculating a change amount in one heartbeat period of the measured blood vessel diameter;
Further comprising
The determination unit determines a blood pressure state based on the calculated amount of change;
The ultrasonic measurement apparatus according to claim 1. The determination unit determines that the blood pressure is abnormal as low blood pressure;
The ultrasonic measurement apparatus according to claim 1. Measuring the diameter of the blood vessel with ultrasound,
Determining a blood pressure state including a blood pressure abnormality based on the measured change in blood vessel diameter for at least one heartbeat period;
An ultrasonic measurement method including:

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