JP2011024676A - Pulse wave velocity computing apparatus, sphygmomanometer, method for controlling pulse wave velocity computing apparatus, program for controlling pulse wave velocity computing apparatus, and computer-readable recording medium recording the program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To compute the pulse wave velocity by determining the pulse waveforms suitable for computing the pulse wave velocity and using at least two pulse waveforms suitable for computing the pulse wave velocity. <P>SOLUTION: The pulse wave velocity computing apparatus 1 includes a pulse wave data acquisition part 41 for acquiring part of the respective pulse waveforms detected from a plurality of regions of one living body in the same period of computation, a waveform applicability determination part 43 for determining whether the respective pulse waveforms in the period of computation acquired by the pulse wave data acquisition part 41 are applicable to the computation of the pulse wave velocity, and a pulse wave velocity computing part 44 for computing the pulse wave velocity using at least two pulse waveforms determined by the waveform applicability determination part 43 as applicable to the computation of the pulse wave velocity. With this structure, the pulse waveforms suitable for computing the pulse wave velocity are determined, and the pulse wave velocity can be computed by using at least two pulse waveforms suitable for computing the pulse wave velocity. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a pulse wave velocity calculating device, a blood pressure measuring device, a method for controlling a pulse wave velocity calculating device, and a pulse wave velocity calculating device that calculate a pulse wave velocity using a detected pulse wave waveform. The present invention relates to a control program and a computer-readable recording medium on which the program is recorded.

  In recent years, with increasing health consciousness, there is a need for a measuring instrument that can constantly measure biological information such as blood pressure in daily life. By constantly measuring biometric information, it is possible to detect changes in the user's physical condition and signs of illness. Also, by recording and accumulating the measurement results, it is possible to prevent disease.

  When measuring blood pressure, which is one of the biological information, the oscillometric method and the auscultation method (Korotkoff sound method) are generally used. The oscillometric method is a method in which a cuff is wound around one of the extremities, the cuff is pressurized and then depressurized, and blood pressure is measured by changing the cuff pressure in the process of pressurization and depressurization. The auscultation method is a method of measuring blood pressure using a Korotkoff sound, which is a sound generated when an artery is clamped with a cuff.

  Therefore, when blood pressure is measured using an oscillometric method or an auscultation method, it is necessary to press the measurement site with a cuff, which gives a sense of restraint or discomfort to the measurer.

  Therefore, as a method for measuring blood pressure without pressing the measurement site with a cuff, a method using a pulse wave velocity is known. It is known that there is a strong correlation between the variation in the pulse wave velocity and the variation in blood pressure, and blood pressure is measured using the correlation. However, the pulse wave propagation speed may not be measured accurately because the pulse wave signal is disturbed by the wearing state of the pulse wave sensor, the physiological state of the person being measured, the influence of body movement, and the like. Therefore, in order to accurately measure the pulse wave propagation velocity, a method for easily determining whether or not the pulse wave signal can be accurately measured is desired.

  Therefore, in Patent Document 1, a feature amount is calculated from the amplitude, period, and rise time of a pulse wave waveform, and the pulse waveform is classified into a normal waveform, a body motion waveform, and an arrhythmia waveform using the calculated feature amount. A discrimination device is described.

  In Patent Document 2, the sharpness of the pulse wave and the average sharpness which is the average of the sharpness are calculated, and the pulse wave whose comparison value between the sharpness and the average sharpness is within a predetermined range is appropriately selected. An apparatus for determining a pulse wave capable of diagnosing arterial stenosis is described.

  Furthermore, in Patent Document 3, the ratio between the peak height of the first peak of the waveform obtained by first-order differentiation of the pulse waveform and the peak height of the first peak in the pulse waveform before differentiation, There is described a pulse wave signal analysis device that determines whether a pulse wave waveform is good or bad depending on whether or not the product of the rise of the pulse wave waveform in the signal and the time from the peak to the peak in the waveform is within a predetermined range.

Japanese Patent Laid-Open No. 4-285530 (released on October 9, 1992) JP 2004-136107 A (published on May 13, 2004) JP 2006-263354 A (published on October 5, 2006)

  In daily life, in order to constantly measure biological information, it is necessary to consider the attachment and restraint of the measuring device to the living body, that is, not to disturb the daily activities of the living body as much as possible. A commonly used pulse wave velocity calculating device calculates a time difference between electrocardiogram information from the heart and a pulse wave signal obtained from one pulse wave sensor, The pulse wave velocity is calculated from the distance between the two points and the time difference.

  However, the electrocardiograph needs to attach electrodes to the chest and cannot be easily worn in daily life. In addition, the overall apparatus becomes large. Therefore, it is desirable to use two pulse wave sensors without using an electrocardiograph in order to prevent the daily activities of the living body as much as possible. In order to reduce the size of the apparatus, it is desirable to shorten the distance between the two pulse wave sensors as much as possible.

  However, if the distance between the two pulse wave sensors is shortened, the following adverse effects occur. That is, for example, when an experiment is actually performed with a pulse wave sensor attached, when the distance between the two pulse wave sensors is about 15 cm, a value of about 20 ms is obtained as a pulse wave propagation time for a healthy person. However, if the pulse waveform is disturbed for some reason, an error of about 20 ms may occur. Therefore, when the distance between the two pulse wave sensors is short, if the pulse wave waveform is disturbed, the measurement accuracy of the pulse wave propagation time is affected. This is considered to be caused by a slight change in the rising portion of the pulse waveform due to the pulse waveform.

  FIG. 12 is a diagram showing only the rising portion of the pulse wave signal measured when the distance between the measurement sites of the pulse wave sensor attached to two predetermined measurement sites is short.

  In FIG. 12, the waveform of the pulse wave signal measured by the first pulse wave sensor is a pulse wave waveform 1101, and the waveform of the pulse wave signal measured by the second pulse wave sensor is a pulse wave waveform 1201. Then, the waveform of the pulse wave signal measured by the first pulse wave sensor under ideal measurement conditions is shown as a pulse wave waveform 1301 by a broken line. That is, the pulse wave waveform 1101 indicates a case where the pulse wave waveform is disturbed for some reason.

  The minimum point of the pulse wave waveform 1101 is a minimum point 1102, the minimum point of the pulse wave waveform 1301 is a minimum point 1302, and the minimum point of the pulse wave waveform 1201 is a minimum point 1202.

  In this case, the pulse wave propagation time for calculating the pulse wave propagation velocity is a pulse wave propagation time PTT which is a difference between the minimum point 1102 and the minimum point 1202 when the measurement result is used as it is. However, since the actual pulse wave propagation time is the pulse wave propagation time PTT ′ which is the difference between the minimum point 1302 and the minimum point 1202, an error is caused by the difference between the pulse wave propagation time PTT and the pulse wave propagation time PTT ′. become.

  The waveform disturbance as described above does not mean that the amplitude, period, and rise time of the pulse wave waveform have changed greatly, and the technique described in Patent Document 1 cannot determine abnormality.

  In addition, the sharpness of the pulse waveform does not change significantly, and the technique described in Patent Document 2 cannot determine abnormality.

  Furthermore, the ratio of the peak height of the first peak, which is the first peak of the waveform obtained by first-order differentiation of the pulse wave waveform, to the peak height of the first peak in the pulse waveform before differentiation, and the pulse wave signal The product of the time from the rise of the pulse wave waveform to the peak of the same waveform is likely to be in a predetermined range, and it is difficult to determine that the technique described in Patent Document 3 is abnormal.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to determine a pulse wave waveform suitable for calculating a pulse wave propagation velocity and to determine at least two pulses suitable for calculating the pulse wave propagation velocity. The object is to realize a pulse wave velocity calculation device that calculates a pulse wave velocity using a wave waveform.

  In order to solve the above-described problem, a pulse wave velocity calculating apparatus according to the present invention calculates a pulse wave velocity using a pulse wave waveform of a pulse wave detected from at least two locations of one living body. In the velocity calculation device, a pulse wave waveform acquisition unit that acquires a portion of the same calculation period from each pulse wave waveform detected from a plurality of locations of one living body, and the calculation period acquired by the pulse wave waveform acquisition unit Waveform determining means for determining whether or not each of the pulse wave waveforms can be used for calculating the pulse wave velocity, and among the pulse waveform determined that the waveform determining means can be used for calculating the pulse wave velocity And a pulse wave velocity calculating means for calculating a pulse wave velocity using at least two pulse wave waveforms.

  The pulse wave velocity calculating apparatus according to the present invention also includes a pulse wave velocity calculating apparatus that calculates a pulse wave velocity using pulse wave waveforms detected from at least two locations of one living body. A pulse wave waveform acquisition step of acquiring a portion of the same period from each pulse wave waveform detected from a plurality of locations of one living body, and the pulse wave waveform acquisition step Of each of the pulse wave waveforms determined to be usable for calculation of the pulse wave propagation velocity in the waveform determination step and the waveform determination step for determining whether or not each pulse wave waveform can be used for calculation of the pulse wave propagation velocity. And a pulse wave velocity calculation step for calculating a pulse wave velocity using at least two pulse wave waveforms.

  According to the above configuration or method, it is determined whether or not the portions of the same pulse wave waveform detected from a plurality of locations of one living body can be used for calculating the pulse wave propagation velocity. The pulse wave propagation velocity is calculated using at least two pulse wave waveforms out of the pulse wave waveforms determined to be usable for calculating the wave propagation velocity. The calculation period is a period used for calculating the pulse wave propagation velocity for the pulse wave waveform, for example, a period of one pulse wave.

  As a result, the pulse wave velocity can be calculated using at least two pulse wave waveforms suitable for calculating the pulse wave velocity, so that the pulse wave velocity can be accurately calculated.

  In addition, even if the distance between pulse wave measurement sites is short and small disturbances in the pulse wave waveform affect the measurement accuracy, according to the above configuration, the pulse wave waveform causing the small disturbances is converted into a pulse wave. Since the pulse wave waveform that can be used to calculate the propagation velocity is not used, the pulse wave propagation velocity is accurately calculated using the pulse wave waveform suitable for calculating the pulse wave propagation velocity, regardless of the distance between the pulse wave measurement sites. can do.

  In the pulse wave velocity calculation device according to the present invention, the waveform determination means uses the pulse waveform waveform at the time when the differential waveform obtained by differentiating the pulse wave waveform becomes the maximum point as the differential maximum point. An amplitude differential element that is a ratio of displacement from the local minimum point of the pulse wave waveform to the next differential maximum point of the local minimum point with respect to the amplitude of the pulse wave waveform is obtained, and when the amplitude differential element is in the first range, The wave waveform may be determined to be usable for calculating the pulse wave velocity.

  According to said structure, a waveform determination means determines with the pulse wave waveform which has an amplitude differential element in the 1st range being usable for calculation of a pulse wave propagation velocity.

  The amplitude differential element does not change greatly every beat if the pulse wave is detected in an ideal state. On the other hand, when the pulse wave is disturbed for some reason and the position of the minimum point of the pulse wave waveform changes as compared with the case where the pulse wave waveform is detected in an ideal state, the amplitude differential element changes. Therefore, if the first range is set to a range that the amplitude differential element can take if the pulse wave is detected in an ideal state, the position of the minimum point changes compared to the ideal state. The pulse waveform that is not present can be determined as a pulse waveform suitable for calculating the pulse wave velocity.

  The pulse wave propagation velocity can be accurately calculated by using the pulse wave waveform in which the position of the minimum point is not changed compared to the ideal state.

  In addition, the amplitude differential element is larger for each beat if the pulse wave is detected in an ideal state regardless of whether the distance between the measurement points of the pulse wave is long or short. It does not change. Therefore, by using the pulse wave waveform in which the amplitude differential element is included in the first range, it is possible to accurately calculate the pulse wave propagation velocity regardless of the distance between the measurement points of the pulse wave.

  In the pulse wave velocity calculation device according to the present invention, the waveform determination means uses the pulse waveform waveform at the time when the differential waveform obtained by differentiating the pulse wave waveform becomes the maximum point as the differential maximum point. An interval differential element which is a ratio of time from the previous minimum point of the adjacent minimum points to the next differential maximum point of the minimum point with respect to the time between adjacent minimum points of When the is in the second range, the pulse waveform may be determined to be usable for calculating the pulse wave velocity.

  According to the above configuration, the waveform determining means determines that the pulse wave waveform having the interval differential element in the second range can be used for calculating the pulse wave propagation velocity.

  The interval differential element does not change greatly every beat if the pulse wave is detected in an ideal state. On the other hand, when the pulse wave is disturbed for some reason and the position of the minimum point of the pulse wave waveform changes as compared with the case where the pulse wave is detected in an ideal state, the interval differential element changes. Therefore, if the pulse wave is detected in an ideal state, if the second range is set to a range that the interval differential element can take, the position of the minimum point changes compared to the ideal state. A pulse wave waveform that has not been determined can be determined as a pulse wave waveform suitable for calculating the pulse wave velocity.

  The pulse wave propagation velocity can be accurately calculated by using the pulse wave waveform in which the position of the minimum point is not changed compared to the ideal state.

  In addition, the interval differential element is large for each beat if the pulse wave is detected in an ideal state regardless of whether the distance between pulse wave measurement points is long or short. It does not change. Therefore, by using the pulse wave waveform included in the second range as the interval differential element, the pulse wave propagation velocity can be accurately calculated regardless of the distance between the pulse wave measurement points. .

  In the pulse wave propagation velocity calculation device according to the present invention, the waveform determination means is arranged to start from the previous minimum point of the adjacent local minimum points to the time between the adjacent local minimum points of the pulse waveform. An interval maximum element that is a ratio of the time to the local maximum point is obtained, and when the interval maximum element is in the third range, it is determined that the pulse wave waveform can be used for calculating the pulse wave propagation velocity. Also good.

  According to the above configuration, the waveform determining means determines that the pulse waveform having the interval maximum element in the third range can be used for calculating the pulse wave propagation velocity.

  The interval maximum element does not change greatly every beat if the pulse wave is detected in an ideal state. On the other hand, when the pulse wave is disturbed for some reason and the position of the minimum point of the pulse wave waveform changes as compared with the case where the pulse wave is detected in an ideal state, the interval differential element changes. Therefore, if the third range is set to a range that the interval maximum element can take if the pulse wave is detected in an ideal state, the position of the minimum point changes compared to the ideal state. The pulse waveform that is not present can be determined as a pulse waveform suitable for calculating the pulse wave velocity.

  The pulse wave propagation velocity can be accurately calculated by using the pulse wave waveform in which the position of the minimum point is not changed compared to the ideal state.

  In addition, the maximum element of the interval is large for each beat if the pulse wave is detected in an ideal state regardless of whether the distance between pulse wave measurement points is long or short. It does not change. Therefore, by using the pulse wave waveform included in the third range as the interval maximum element, it is possible to accurately calculate the pulse wave propagation velocity regardless of the distance between pulse wave measurement locations. .

  In the pulse wave velocity calculation device according to the present invention, a pulse wave detection unit that is attached to the living body and detects the pulse wave from the living body, and a first after the pulse wave detection unit is attached to the living body. From the pulse wave waveform of the pulse wave detected by the pulse wave detector during the detection period, obtain the amplitude differential element for each calculation period, obtain an average value of the obtained amplitude differential element in the first detection period, Range setting means for setting the first range from a first lower limit value obtained by subtracting a predetermined range determined value from an average value to a first upper limit value obtained by adding the range determined value to the average value. It may be.

  According to said structure, a range setting means sets a 1st range from the average value of the amplitude differential element of the pulse wave waveform in a 1st detection period after a pulse wave detection part is mounted | worn. And the range setting which considered the state after mounting | wearing of a pulse-wave detection part can be performed by using the pulse-wave waveform after mounting | wearing a pulse-wave detection part. The pulse wave detection unit is mounted by setting the first range from the first lower limit value obtained by subtracting the range determination value from the average value to the first upper limit value obtained by adding the range determination value to the average value. It is possible to set a range in consideration of the manner, individual differences, blood vessel conditions at that time, and the like. As a result, compared to the case where the first range is set in advance, it is possible to set the range in accordance with the actual situation, and whether or not it can be used for calculation of the pulse wave propagation velocity is more in accordance with the actual situation. Can be determined.

  The first detection period is a period in which an appropriate average value can be calculated and is as short as possible. For example, a period in which the pulse wave is 20 beats can be mentioned. The range decision value is used to calculate the pulse wave velocity when the set range is from the lower limit value obtained by subtracting the range decision value to the average value to the upper limit value obtained by adding the range decision value to the average value. It is a value which can determine the pulse wave waveform which can be performed, for example, the value of 10% of the said average value can be mentioned.

  In the pulse wave velocity calculation device according to the present invention, a pulse wave detection unit that is attached to the living body and detects the pulse wave from the living body, and a first after the pulse wave detection unit is attached to the living body. From the pulse wave waveform of the pulse wave detected by the pulse wave detection unit during the detection period, obtain the interval differential element for each calculation period, obtain an average value of the obtained interval differential element in the first detection period, Range setting means for setting the second range from a second lower limit value obtained by subtracting a predetermined range determination value from the average value to a second upper limit value obtained by adding the range determination value to the average value. It may be.

  According to said structure, a range setting means sets a 2nd range from the average value of the interval differential element of the pulse wave waveform in a 1st detection period after a pulse wave detection part is mounted | worn. And the range setting which considered the state after mounting | wearing of a pulse-wave detection part can be performed by using the pulse-wave waveform after mounting | wearing a pulse-wave detection part. In addition, the second range from the second lower limit value obtained by subtracting the range determined value from the average value to the second upper limit value obtained by adding the range determined value to the average value is used to mount the pulse wave detector. It is possible to set a range in consideration of the manner, individual differences, and the blood vessel state at that time. As a result, compared to the case where the second range is set in advance, it is possible to set the range in accordance with the actual situation and determine whether it can be used for the calculation of the pulse wave propagation velocity. Can be determined.

  In the pulse wave velocity calculation device according to the present invention, a pulse wave detection unit that is attached to the living body and detects the pulse wave from the living body, and a first after the pulse wave detection unit is attached to the living body. From the pulse wave waveform of the pulse wave detected by the pulse wave detection unit during the detection period, obtain the interval maximum element for each calculation period, determine the average value of the obtained interval maximum element in the first detection period, Range setting means for setting the third range from a third lower limit value obtained by subtracting a predetermined range determined value from the average value to a third upper limit value obtained by adding the range determined value to the average value. It may be.

  According to said structure, a range setting means sets a 3rd range from the average value of the space | interval maximum element of the pulse wave waveform in a 1st detection period after a pulse wave detection part is mounted | worn. And the range setting which considered the state after mounting | wearing of a pulse-wave detection part can be performed by using the pulse-wave waveform after mounting | wearing a pulse-wave detection part. In addition, the third wave range from the third lower limit value obtained by subtracting the range determination value from the average value to the third upper limit value obtained by adding the range determination value to the average value is used to install the pulse wave detection unit. It is possible to set a range in consideration of the manner, individual differences, and the blood vessel state at that time. As a result, compared to the case where the third range is set in advance, it is possible to set the range in accordance with the actual situation and determine whether it can be used for the calculation of the pulse wave propagation velocity. Can be determined.

  In the pulse wave velocity calculation device according to the present invention, the pulse wave detection unit that is attached to the living body and detects the pulse wave from the living body, and the second immediately before the waveform determination means determines the pulse wave waveform. From the pulse wave waveform of the pulse wave detected by the pulse wave detection unit during the detection period, obtain the amplitude differential element for each calculation period, obtain an average value of the obtained amplitude differential element in the second detection period, Range setting means for setting the first range from a fourth lower limit value obtained by subtracting a predetermined range determined value from the average value to a fourth upper limit value obtained by adding the range determined value to the average value. It may be.

  According to said structure, a range setting means sets a 1st range from the average value of the amplitude differential element of the pulse wave waveform in the 2nd detection period just before a waveform determination means determines a pulse wave waveform. Since the state of the human blood vessel changes from time to time, it is possible to set the range in consideration of the state of the blood vessel by setting the range using the pulse wave waveform immediately before the determination. it can. Thereby, it can be determined whether or not the pulse wave waveform can be used for calculating the pulse wave propagation velocity in accordance with the actual condition at the time of determination.

  Note that the second detection period is a period in which an appropriate average value can be calculated and is as short as possible, and can include a period of about 20 seconds, for example.

  In the pulse wave velocity calculation device according to the present invention, the pulse wave detection unit that is attached to the living body and detects the pulse wave from the living body, and the second immediately before the waveform determination means determines the pulse wave waveform. From the pulse wave waveform of the pulse wave detected by the pulse wave detection unit during the detection period, obtain the interval differential element for each calculation period, obtain the average value of the obtained interval differential element in the second detection period, Range setting means for setting the second range from a fifth lower limit value obtained by subtracting a predetermined range determination value from the average value to a fifth upper limit value obtained by adding the range determination value to the average value. It may be.

  According to said structure, a range setting means sets a 2nd range from the average value of the interval differential element of the pulse wave waveform in the 2nd detection period just before a waveform determination means determines a pulse wave waveform. Since the state of the human blood vessel changes from time to time, it is possible to set the range in consideration of the state of the blood vessel by setting the range using the pulse wave waveform immediately before the determination. it can. Thereby, it can be determined whether or not the pulse wave waveform can be used for calculating the pulse wave propagation velocity in accordance with the actual condition at the time of determination.

  In the pulse wave velocity calculation device according to the present invention, the pulse wave detection unit that is attached to the living body and detects the pulse wave from the living body, and the second immediately before the waveform determination means determines the pulse wave waveform. From the pulse wave waveform of the pulse wave detected by the pulse wave detection unit during the detection period, obtain the interval maximum element for each calculation period, obtain the average value of the obtained interval maximum element in the second detection period, Range setting means for setting the predetermined third range from a sixth lower limit value obtained by subtracting a predetermined range determination value from the average value to a sixth upper limit value obtained by adding the range determination value to the average value; May be provided.

  According to said structure, a range setting means sets a 3rd range from the average value of the space | interval local maximum element of the pulse wave waveform in the 2nd detection period immediately before a waveform determination means determines a pulse wave waveform. Since the state of the human blood vessel changes from time to time, it is possible to set the range in consideration of the state of the blood vessel by setting the range using the pulse wave waveform immediately before the determination. it can. Thereby, it can be determined whether or not the pulse wave waveform can be used for calculating the pulse wave propagation velocity in accordance with the actual condition at the time of determination.

  In the pulse wave propagation velocity calculation device according to the present invention, the waveform determination means has a maximum difference in the differential waveform obtained by differentiating the pulse wave waveform with respect to the two pulse wave waveforms in the calculation period acquired by the pulse wave acquisition means. The amplitude that is the ratio of the displacement from the minimum point of the pulse wave waveform to the next differential maximum point of the pulse point waveform relative to the amplitude of the pulse wave waveform, with the point of the pulse waveform at the time of A differential element is obtained, and when the ratio of the amplitude differential element of the two pulse wave waveforms is in the fourth range, it is determined that the two pulse wave waveforms can be used for calculation of the pulse wave velocity, The pulse wave velocity calculating unit may calculate the pulse wave velocity using two pulse wave waveforms determined by the waveform determining unit to be usable for calculating the pulse wave velocity.

  According to the above configuration, when the ratio of the amplitude differential element is in the fourth range with respect to the two pulse wave waveforms acquired by the pulse wave acquisition unit, the waveform determination unit transmits the two pulse wave waveforms to the pulse wave It is determined that it can be used for speed calculation.

  Then, when the increase and decrease of the amplitude differential element of the two pulse wave waveforms are similar, if the amplitude differential element itself is used for the determination, the pulse wave waveform is converted into the pulse wave even though there is no abnormality in the pulse wave waveform. There is a possibility that it can be determined that it cannot be used to calculate the propagation velocity.

  On the other hand, if there is no abnormality in the two pulse wave waveforms, but the increase and decrease of the amplitude differential element of each pulse wave waveform is the same, the amplitude Since the ratio of the differential elements does not change so much, it can be determined that the pulse wave waveform can be used for calculating the pulse wave propagation velocity. Therefore, the pulse wave velocity can be calculated more accurately than in the case where the amplitude differential element itself is used.

  In addition, when one of the amplitude differential elements of two pulse wave waveforms increases and the other decreases, using the amplitude differential element itself causes the pulse wave waveform to propagate through the pulse wave even though the pulse wave waveform is abnormal. There is a possibility that it can be determined that it can be used for speed calculation.

  On the other hand, the ratio of the amplitude differential element changes greatly when one of the amplitude differential elements of the two pulse wave waveforms increases and the other decreases, so the pulse waveform is used for calculating the pulse wave velocity. It can be determined that it is not possible. Therefore, the pulse wave velocity can be calculated more accurately than in the case where the amplitude differential element itself is used.

  In the pulse wave propagation velocity calculation device according to the present invention, the waveform determination means has a maximum difference in the differential waveform obtained by differentiating the pulse wave waveform with respect to the two pulse wave waveforms in the calculation period acquired by the pulse wave acquisition means. The point of the pulse wave waveform at the time to be the differential maximum point, and the time between the adjacent minimum points of the pulse waveform from the previous minimum point of the adjacent minimum points to the above next of the minimum point An interval differential element that is a ratio of time to the differential maximum point is obtained, and when the ratio of the interval differential element of the two pulse wave waveforms is in the fifth range, the two pulse wave waveforms are The pulse wave velocity calculating means determines the pulse wave velocity using the two pulse wave waveforms determined by the waveform determining means to be usable for calculating the pulse wave velocity. It may be calculated.

  According to the above configuration, when the ratio of the interval differential element is within the fifth range for the two pulse wave waveforms acquired by the pulse wave acquisition unit, the waveform determination unit transmits the two pulse wave waveforms to the pulse wave. It is determined that it can be used for speed calculation.

  If the increase and decrease of the interval differential element of the two pulse wave waveforms are approximately the same, if the interval differential element itself is used for the determination, the pulse wave waveform is converted into the pulse wave even though there is no abnormality in the pulse wave waveform. There is a possibility that it can be determined that it cannot be used to calculate the propagation velocity.

  On the other hand, when there is no abnormality in the two pulse wave waveforms, if the increase and decrease of the interval differential element of each pulse wave waveform is about the same, even if each value of the interval differential element increases or decreases, Since the ratio of the differential elements does not change so much, it can be determined that the pulse wave waveform can be used for calculating the pulse wave propagation velocity. Therefore, the pulse wave velocity can be calculated more accurately than in the case where the interval differential element itself is used.

  In addition, when one of the interval differential elements of the two pulse wave waveforms increases and the other decreases, when the interval differential element itself is used, the pulse wave waveform is converted into the pulse wave even though the pulse wave waveform is abnormal. There is a possibility that it can be determined that it can be used to calculate the propagation velocity.

  On the other hand, since the ratio of the interval differential element changes greatly when one of the interval differential elements of the two pulse wave waveforms increases and the other decreases, the pulse waveform is used for calculating the pulse wave velocity. It can be determined that it is not possible. Therefore, the pulse wave velocity can be calculated more accurately than in the case where the interval differential element itself is used.

  In the pulse wave velocity calculating device according to the present invention, the waveform determining means is a time between adjacent minimum points of the pulse wave waveform for two pulse wave waveforms in the calculation period acquired by the pulse wave acquiring means. Is determined as an interval maximum element, which is a ratio of time from the previous minimum point of the adjacent minimum points to the next maximum point of the minimum point, and the ratio of the interval maximum elements of the two pulse wave waveforms is When it is in the sixth range, it is determined that the two pulse wave waveforms can be used for calculating the pulse wave velocity, and the pulse wave velocity calculating means is configured to determine whether the waveform determining means has the pulse wave velocity. The pulse wave velocity may be calculated using two pulse wave waveforms determined to be usable for calculation.

  According to the above configuration, when the ratio of the interval maximum elements is within the sixth range for the two pulse wave waveforms acquired by the pulse wave acquisition unit, the waveform determination unit transmits the two pulse wave waveforms to the pulse wave. It is determined that it can be used for speed calculation.

  If the increase and decrease of the interval maximum elements of the two pulse wave waveforms are approximately the same, if the interval maximum element itself is used for the determination, the pulse waveform is converted into the pulse wave even though there is no abnormality in the pulse waveform. There is a possibility that it can be determined that it cannot be used to calculate the propagation velocity.

  On the other hand, if there is no abnormality in the two pulse wave waveforms, and the increase and decrease of the interval maximum element of each pulse wave waveform are the same, even if each value of the interval maximum element increases and decreases, Since the ratio of the maximal elements does not change so much, it can be determined that the pulse wave waveform can be used for calculation of the pulse wave propagation velocity. Therefore, the pulse wave velocity can be calculated more accurately than in the case where the interval maximum element itself is used.

  In addition, when one of the two maximal elements of the pulse wave waveform increases and the other decreases, using the maximal element itself causes the pulse wave waveform to propagate through the pulse wave even though the pulse wave waveform is abnormal. There is a possibility that it can be determined that it can be used for speed calculation.

  On the other hand, since the ratio of the interval maximum elements changes greatly when one of the interval maximum elements of the two pulse wave waveforms increases and the other decreases, the pulse waveform is used for calculating the pulse wave propagation velocity. It can be determined that it is not possible. Therefore, the pulse wave velocity can be calculated more accurately than in the case where the interval maximum element itself is used.

  In the pulse wave velocity calculation device according to the present invention, after the two pulse wave detection units that are attached to the living body and detect the pulse wave from the living body and the two pulse wave detection units are both attached to the living body. The ratio of the amplitude differential element for each calculation period of the pulse waveform of each pulse wave detected by the two pulse wave detectors in the first detection period is determined, and the ratio of the calculated amplitude differential element is An average value in one detection period is obtained, and the fourth lower limit value is obtained by subtracting a predetermined range determination value from the average value to a seventh upper limit value obtained by adding the range determination value to the average value. And a range setting means for making the above range.

  According to the above configuration, the range setting means sets the fourth range from the average value of the ratios of the amplitude differential elements of the pulse wave waveform in the first detection period after the pulse wave detector is mounted. And the range setting which considered the state after mounting | wearing of a pulse-wave detection part can be performed by using the pulse-wave waveform after mounting | wearing a pulse-wave detection part. In addition, since the fourth range is from the seventh lower limit value obtained by subtracting the range determination value from the average value to the seventh upper limit value obtained by adding the range determination value to the average value, It is possible to set a range in consideration of the manner, individual differences, and the blood vessel state at that time. As a result, compared to the case where the fourth range is set in advance, it is possible to set the range in accordance with the actual situation, and whether or not it can be used for the calculation of the pulse wave propagation speed is more in accordance with the actual situation. Can be determined.

  In the pulse wave velocity calculation device according to the present invention, after the two pulse wave detection units that are attached to the living body and detect the pulse wave from the living body and the two pulse wave detection units are both attached to the living body. The ratio of the interval differential element for each calculation period of the pulse wave waveform of each pulse wave detected by the two pulse wave detectors in the first detection period is determined, and the ratio of the calculated interval differential element is An average value in one detection period is obtained, and an eighth lower limit value obtained by subtracting a predetermined range determination value from the average value to an eighth upper limit value obtained by adding the range determination value to the average value is the fifth value. And a range setting means for making the above range.

  According to the above configuration, the range setting means sets the fifth range from the average value of the ratios of the interval differential elements of the pulse wave waveform in the first detection period after the pulse wave detector is mounted. And the range setting which considered the state after mounting | wearing of a pulse-wave detection part can be performed by using the pulse-wave waveform after mounting | wearing a pulse-wave detection part. Further, the pulse wave detection unit is mounted by setting the fifth range from the eighth lower limit value obtained by subtracting the range determination value from the average value to the eighth upper limit value obtained by adding the range determination value to the average value. It is possible to set a range in consideration of the manner, individual differences, and the blood vessel state at that time. As a result, compared to the case where the fifth range is set in advance, it is possible to set the range in accordance with the actual situation, and whether or not it can be used for the calculation of the pulse wave propagation velocity is more in accordance with the actual situation. Can be determined.

  In the pulse wave velocity calculation device according to the present invention, after the two pulse wave detection units that are attached to the living body and detect the pulse wave from the living body and the two pulse wave detection units are both attached to the living body. To the ratio of the interval maximum elements for each calculation period of the pulse wave waveforms of the respective pulse waves detected by the two pulse wave detectors in the first detection period, and the ratio of the calculated interval maximum elements An average value in one detection period is obtained, and the ninth lower limit value obtained by subtracting a predetermined range determination value from the average value to the ninth upper limit value obtained by adding the range determination value to the average value is the sixth value. And a range setting means for making the above range.

  According to said structure, a range setting means sets a 6th range from the average value of the ratio of the space | interval local maximum element of a pulse wave waveform in a 1st detection period after a pulse wave detection part is mounted | worn. And the range setting which considered the state after mounting | wearing of a pulse-wave detection part can be performed by using the pulse-wave waveform after mounting | wearing a pulse-wave detection part. In addition, the pulse wave detection unit can be mounted by setting the sixth range from the ninth lower limit value obtained by subtracting the range determination value from the average value to the ninth upper limit value obtained by adding the range determination value to the average value. It is possible to set a range in consideration of the manner, individual differences, and the blood vessel state at that time. As a result, compared to the case where the sixth range is set in advance, it is possible to set the range in accordance with the actual situation, and whether or not it can be used for calculating the pulse wave propagation velocity is more in accordance with the actual situation. Can be determined.

  In the pulse wave velocity calculation apparatus according to the present invention, the second pulse wave detection unit that is attached to the living body and detects the pulse wave from the living body, and the second immediately before the waveform determination unit determines the pulse wave waveform. The ratio of the amplitude differential element for each calculation period of the pulse waveform of each pulse wave detected by the two pulse wave detectors during the detection period is obtained, and the second detection of the ratio of the obtained amplitude differential element is obtained. An average value in a period is obtained, and the tenth lower limit value obtained by subtracting a predetermined range determination value from the average value to the tenth upper limit value obtained by adding the range determination value to the average value is referred to as the fourth range. And a range setting means for performing the above.

  According to the above configuration, the range setting unit sets the fourth range from the average value of the ratios of the amplitude differential elements of the pulse waveform in the second detection period immediately before the waveform determination unit determines the pulse waveform. To do. Since the state of the human blood vessel changes from time to time, it is possible to set the range in consideration of the state of the blood vessel by setting the range using the pulse wave waveform immediately before the determination. it can. Thereby, it can be determined whether or not the pulse wave waveform can be used for calculating the pulse wave propagation velocity in accordance with the actual condition at the time of determination.

  In the pulse wave velocity calculation apparatus according to the present invention, the second pulse wave detection unit that is attached to the living body and detects the pulse wave from the living body, and the second immediately before the waveform determination unit determines the pulse wave waveform. The ratio of the interval differential element for each calculation period of the pulse waveform of each pulse wave detected by the two pulse wave detectors during the detection period is calculated, and the second detection of the ratio of the calculated interval differential element is performed. An average value in a period is obtained, and an eleventh lower limit value obtained by subtracting a predetermined range determination value from the average value to an eleventh upper limit value obtained by adding the range determination value to the average value is referred to as the fifth range. And a range setting means for performing the above.

  According to the above configuration, the range setting means sets the fifth range from the average value of the ratios of the interval differential elements of the pulse waveform in the second detection period immediately before the waveform determination means determines the pulse waveform. To do. Since the state of the human blood vessel changes from time to time, the range can be set in consideration of the state of the blood vessel at that time by setting the range using the pulse wave waveform immediately before the determination. . Thereby, it can be determined whether or not the pulse wave waveform can be used for calculating the pulse wave propagation velocity in accordance with the actual condition at the time of determination.

  In the pulse wave velocity calculation apparatus according to the present invention, the second pulse wave detection unit that is attached to the living body and detects the pulse wave from the living body, and the second immediately before the waveform determination unit determines the pulse wave waveform. The ratio of the interval maximum elements for each calculation period of the pulse waveform of each pulse wave detected by the two pulse wave detectors during the detection period is obtained, and the second detection of the ratio of the calculated interval maximum elements is performed. An average value in a period is obtained, and a twelfth lower limit value obtained by subtracting a predetermined range determination value from the average value to a twelfth upper limit value obtained by adding the range determination value to the average value is referred to as the sixth range. And a range setting means for performing the above.

  According to the above configuration, the range setting unit sets the sixth range from the average value of the ratios of the interval maximum components of the pulse waveform in the second detection period immediately before the waveform determination unit determines the pulse waveform. To do. Since the state of the human blood vessel changes from time to time, the range can be set in consideration of the state of the blood vessel at that time by setting the range using the pulse wave waveform immediately before the determination. . Thereby, it can be determined whether or not the pulse wave waveform can be used for calculating the pulse wave propagation velocity in accordance with the actual condition at the time of determination.

  In the pulse wave velocity calculating apparatus according to the present invention, when the waveform determining unit determines that any of the pulse wave waveforms acquired by the pulse wave acquiring unit cannot be used for calculating the pulse wave velocity, the determination result is obtained. You may provide the presentation means to present.

  According to the above configuration, since any of the pulse wave waveforms acquired by the pulse wave acquisition unit cannot be used for calculating the pulse wave propagation speed, the determination result is presented. It can be recognized that it cannot be used for calculation of.

  In addition, when the number of times when it is determined that the pulse wave waveform cannot be used to calculate the pulse wave velocity exceeds a predetermined number (for example, 5 times), it is assumed that the degree of attachment of the pulse wave detection unit is defective. Thus, the user can recognize that the mounting condition of the pulse wave detection unit is poor.

  A blood pressure measurement device comprising the pulse wave velocity calculating device and a blood pressure value estimating means for estimating a blood pressure value using the pulse wave velocity calculated by the pulse wave velocity calculating device has the above-described effects. be able to.

  The pulse wave propagation velocity calculation device may be realized by a computer. In this case, the pulse wave propagation velocity for realizing the pulse wave propagation velocity calculation device by a computer by operating the computer as each of the above-described means. A control program for the speed calculation device and a computer-readable recording medium that records the control program also fall within the scope of the present invention.

  As described above, the pulse wave velocity calculation device according to the present invention includes a pulse wave waveform acquisition unit that acquires a portion of the same calculation period from each pulse wave waveform detected from a plurality of locations of one living body, A waveform determination unit that determines whether each pulse waveform of the calculation period acquired by the pulse waveform acquisition unit can be used to calculate a pulse wave propagation speed; and And a pulse wave velocity calculating means for calculating a pulse wave velocity using at least two of the pulse wave waveforms determined to be usable for calculation.

  Further, the control method of the pulse wave velocity calculating device according to the present invention includes a pulse wave waveform acquisition step of acquiring a part of the same period from each pulse wave waveform detected from a plurality of locations of one living body, and the pulse A waveform determination step for determining whether or not each pulse waveform of the period acquired in the wave waveform acquisition step can be used for calculation of the pulse wave propagation velocity; and for calculating the pulse wave propagation velocity in the waveform determination step. A pulse wave velocity calculating step for calculating a pulse wave velocity using at least two of the pulse wave waveforms determined to be usable.

  As a result, the pulse wave velocity can be calculated using at least two pulse wave waveforms suitable for calculating the pulse wave velocity, so that the pulse wave velocity can be accurately calculated.

  In addition, even if the distance between pulse wave measurement sites is short and small disturbances in the pulse wave waveform affect the measurement accuracy, according to the above configuration, the pulse wave waveform causing the small disturbances is converted into a pulse wave. Since the pulse wave waveform that can be used to calculate the propagation velocity is not used, the pulse wave propagation velocity is accurately calculated using the pulse wave waveform suitable for calculating the pulse wave propagation velocity, regardless of the distance between the pulse wave measurement sites. There is an effect that can be done.

1, showing an embodiment of the present invention, is a block diagram illustrating a main configuration of a pulse wave velocity calculation device. FIG. In the said embodiment, it is a figure which shows the pulse wave waveform of the pulse wave data for 1 beat which the pulse wave data acquisition part acquired. In the said embodiment, it is a figure which shows the relationship between an amplitude differential element and pulse wave propagation time. In the said embodiment, it is a figure which shows the relationship between an interval differential element and pulse wave propagation time. In the said embodiment, it is a figure which shows the relationship between a space | interval maximum element and a pulse wave propagation time. In the said embodiment, it is a figure which shows the case where the propriety determination element of a 1st pulse wave waveform and a 2nd pulse wave waveform changes to the same direction. In the said embodiment, it is a figure which shows the case where the suitability determination element of a 1st pulse wave waveform and a 2nd pulse wave waveform changes to a reverse direction. In the said embodiment, it is a flowchart which shows the flow of a process of the pulse wave velocity calculation apparatus. 5 is a flowchart showing a flow of a range reference value initial setting process in the embodiment. In the said embodiment, it is a flowchart which shows the flow of the suitability determination process of a pulse wave waveform. 5 is a flowchart showing a flow of a range reference value update process in the embodiment. It is a block diagram which shows the principal part structure of the blood-pressure measuring apparatus which concerns on this Embodiment. In the said embodiment, it is a flowchart which shows the flow of a process in a blood pressure measuring device. In prior art, it is the figure which showed only the rising part of the pulse wave signal measured when the distance between the measurement parts of the pulse wave sensor with which two predetermined measurement parts were mounted | worn is short.

  An embodiment of the present invention will be described below with reference to FIGS.

  The pulse wave velocity calculation device 1 according to the present embodiment is a pulse wave waveform of a pulse wave detected by a first pulse wave sensor (pulse wave detection unit) 11 and a second pulse wave sensor (pulse wave detection unit) 12. It is determined whether the waveform during the calculation period is suitable for calculating the pulse wave velocity using the elements of the pulse waveform when the pulse wave velocity becomes abnormal, and the pulse waveform determined to be suitable Is used to calculate the pulse wave velocity. Thereby, the case where the pulse wave propagation velocity becomes abnormal can be eliminated, and the pulse wave propagation velocity can be accurately calculated.

  FIG. 1 is a block diagram of a pulse wave velocity calculation apparatus 1 according to the present embodiment. As shown in FIG. 1, the pulse wave velocity calculation device 1 includes a first pulse wave sensor 11, a second pulse wave sensor 12, a storage unit 13, a control unit 14, and a display unit 15.

  The first pulse wave sensor 11 and the second pulse wave sensor 12 are sensors for detecting a pulse wave from a living body, and are a light emitting element such as an LED (Light-emitting diode) and a light receiving element such as a PD (Photo diode). It is comprised by. In the present embodiment, the pulse wave waveform of the pulse wave detected by the first pulse wave sensor 11 is the first pulse wave waveform, and the pulse wave waveform of the pulse wave detected by the second pulse wave sensor 12 is the second pulse wave waveform. This is called a pulse wave waveform.

  The principle of detecting a pulse wave from a living body is as follows. Light emitted from the light emitting element enters the living body and is absorbed by blood vessels in the living body. And since the volume of the blood vessel in the living body changes in synchronization with the heartbeat, the amount of incident light absorbed also changes in synchronization with the heartbeat. Therefore, if light incident on the living body and scattered and reflected is detected by the light receiving element, a pulse wave signal synchronized with the heartbeat can be obtained. The wavelength of light emitted from the light emitting element is a wavelength that easily propagates in the living body, and light of about 700 nm to 1000 nm is often used for pulse wave detection.

  In addition, as the mounting positions of the first pulse wave sensor 11 and the second pulse wave sensor 12, a finger, a wrist, an arm, an ear, a carotid artery, and the like are conceivable. In order to realize a wearable biosensor in order to enable continuous measurement, it is preferable to attach it to the peripheral part of the living body. This is because it is considered that the user wearing the erasure part has a lower sense of restraint and discomfort for the user.

  In order to calculate the pulse wave propagation velocity, it is necessary to detect pulse wave signals in at least two measurement sites. In addition, the shorter the distance between the two measurement parts, the shorter the pulse wave propagation time between the two measurement parts, and it is necessary to increase the sampling frequency in order to perform accurate measurement. In addition, the shorter the distance between the two measurement sites, the greater the influence that the measurement error of the pulse wave signal has on the calculation result of the pulse wave velocity. That is, it greatly affects the accuracy of pulse wave velocity calculation.

  For example, when a finger and a wrist are used as the measurement site, the distance between the two measurement sites is about 15 cm. Therefore, if the pulse wave propagation speed is 600 cm / s, a value of 20 ms is obtained as the pulse wave propagation time. The first pulse wave sensor 11 and the second pulse wave sensor 12 are not limited to the above-described method, and may detect a pulse wave using a pressure sensor or the like.

  The storage unit 13 stores information, and includes a nonvolatile storage device such as a flash memory and a ROM (Read Only Memory) and a volatile storage device such as a RAM (Random Access Memory). Examples of contents stored in the nonvolatile storage device include various programs, various operation setting values, and various data. On the other hand, examples of the contents stored in the volatile storage device include a working file and a temporary file. In the present embodiment, the storage unit 13 includes a first pulse wave data storage unit 31 and a second pulse wave data storage unit 32.

  The first pulse wave data storage unit 31 and the second pulse wave data storage unit 32 store the pulse waves detected by the first pulse wave sensor 11 and the second pulse wave sensor 12 together with their times.

  The display unit 15 displays information such as the pulse wave velocity calculated by the pulse wave velocity calculating device 1, whether the first pulse wave sensor 11 and the second pulse wave sensor 12 are worn, and whether the pulse wave is good or bad. Is. The display unit 15 may be implemented by any device as long as it can display information. Specific examples include a liquid crystal display, an organic EL (Electro Luminescence) display, and a plasma display. Etc. Moreover, you may provide the vibrator which transmits information with a vibration with the display part 15. FIG.

  By using the vibrator, information can be transmitted to the user by vibration. For example, even when the user cannot always see the display unit with a wearable measurement device, measurement errors, etc. Information can be transmitted.

  The control unit 14 calculates a pulse wave propagation velocity, and includes a pulse wave data acquisition unit (pulse wave waveform acquisition unit) 41, a suitability range reference value setting unit (range setting unit) 42, and a waveform suitability determination unit (waveform determination). Means, range setting means) 43, pulse wave velocity calculation section (pulse wave velocity calculation means) 44, display control section 45, and wearing quality determination section 46.

  The pulse wave data acquisition unit 41 acquires pulse wave data for a predetermined period from the pulse wave data stored in the first pulse wave data storage unit 31 and the second pulse wave data storage unit 32, and determines whether or not the range is appropriate. This is transmitted to the value setting unit 42, the waveform suitability determination unit 43, and the pulse wave propagation velocity calculation unit 44. As the predetermined period, for example, a period corresponding to one beat of the latest pulse wave can be cited.

  The suitability range reference value setting unit 42 sets a range reference value used by the waveform suitability determination unit 43. The pulse waveform of the pulse wave obtained from the first pulse wave sensor 11 and the second pulse wave sensor 12 is the wearing state of the first pulse wave sensor 11 and the second pulse wave sensor 12, individual differences, and the wearer's current state. It changes depending on the blood vessel condition. Therefore, it is desirable to set the range reference value after the measurement subject wears the first pulse wave sensor 11 and the second pulse wave sensor 12. In addition, since the blood vessel state of the non-measurement person may change even after wearing, it is desirable to update the range reference value. Therefore, the suitability range reference value setting unit 42 performs initial setting and update of the range reference value. A specific setting and updating method will be described later.

  When the range reference value cannot be set, the suitability range reference value setting unit 42 transmits information indicating that to the wearing quality determination unit 46.

  The wearing quality determination unit 46 determines whether or not the first pulse wave sensor 11 and the second pulse wave sensor 12 are worn. Specifically, when information indicating that the range reference value could not be set is acquired from the suitability range reference value setting unit 42, at least one of the first pulse wave sensor 11 and the second pulse wave sensor 12 is correctly attached. It is determined that it is not, and information indicating the determination result is transmitted to the display control unit 45. In addition, when the wearing quality determination unit 46 acquires information that the range reference value could not be set from the suitability range reference value setting unit 42 a predetermined number of times, at least one of the first pulse wave sensor 11 and the second pulse wave sensor 12 is acquired. It may be determined that either one is not correctly mounted.

  As a result, the first pulse wave sensor 11 and the second pulse wave sensor 12 are not properly mounted (such as the mounting pressure), so that the pulse wave waveform is not stable and the pulse wave velocity cannot be calculated. The person to be measured can be prompted to correctly put on the pulse wave sensor 11 and the second pulse wave sensor 12 again.

  When the waveform suitability determination unit 43 obtains the range reference value from the suitability range reference value setting unit 42, the waveform reference waveform obtained from the pulse wave data acquisition unit 41 using the range reference value is converted into a pulse waveform. It is determined whether it is suitable for the calculation of the wave propagation velocity. Specifically, there is a suitability determination element in a range sandwiched by a value obtained by subtracting and adding a predetermined range determination value (in this embodiment, a value of 10% of the range reference value) to the acquired range reference value. Judgment by whether or not.

  In addition, the waveform suitability determination unit 43 stores the suitability determination element calculated for determining the suitability of the waveform in the storage unit 13. Further, the waveform suitability determination unit 43 transmits the determination result to the pulse wave propagation velocity calculation unit 44 and the display control unit 45. A specific method of determination will be described later.

  Next, the suitability determination element will be described with reference to FIG. FIG. 2 is a diagram showing a pulse wave waveform 205 of the pulse wave data for one beat acquired by the pulse wave data acquisition unit 41. As shown in FIG. 2, the pulse wave waveform 205 includes minimum points 201 and 202, a maximum point 203, and a differential maximum point 204. The differential maximum point is a point of the pulse wave waveform before differentiation of time taking the maximum point of the differential waveform obtained by differentiating the pulse wave waveform.

  Further, the amplitude of the pulse wave waveform 205 is the pulse wave amplitude P, the displacement difference between the minimum point 201 and the differential maximum point 204 is displacement D, the time from the minimum point 201 to the next minimum point 202 is the time PT, and from the minimum point 201 The time from the maximum differential point 204 is defined as time DT, and the time from the minimum point 201 to the maximum point 203 is defined as time UT.

  In this embodiment, the propriety determination element is an amplitude differential element (D / P) that is a ratio of the displacement D from the minimum point 201 to the differential maximum point 204 with respect to the pulse wave amplitude P of the pulse wave waveform 205, and the pulse wave waveform. From the differential point (DT / PT), which is the ratio of the time DT from the minimum point 201 to the differential maximum point 204 with respect to the time PT from the minimum point 201 of 205 to the next minimum point 202, from the minimum point 201 of the pulse waveform 205 There are three interval maximum elements (UT / PT) which are ratios of the time UT from the minimum point 201 to the maximum point 203 with respect to the time PT until the next minimum point 202.

  Then, the above three elements of the amplitude differential element, the interval differential element, and the interval maximum element hardly change every beat when the pulse wave can be measured in an ideal state. On the other hand, as shown in FIG. 12, when the pulse wave is disturbed and the position of the minimum point 1302 is changed to the position of the minimum point 1102, the position of the differential maximum point 1103 in the disturbed pulse wave is the original pulse wave. There is no significant change from the position of the differential maximum point 1303 of the waveform 1301. Therefore, when the pulse wave is disturbed, the above three elements change.

  An example of the amplitude differential element will be described with reference to FIG. FIG. 3 is a diagram showing the relationship between the amplitude differential element and the pulse wave propagation time. In FIG. 3, the pulse propagation time is shown on the left vertical axis, and the value of the amplitude differential element is shown on the right vertical axis. The horizontal axis is time. In FIG. 3, the black triangle mark indicates the pulse wave propagation time, the white square mark indicates the amplitude differential element of the first pulse wave waveform, and the white circle mark indicates the amplitude differential element of the second pulse wave waveform. As shown in FIG. 3, when the two amplitude differential elements show approximately constant values, the pulse wave propagation time does not change greatly. However, it can be seen that if any of the amplitude differential elements changes greatly, the pulse wave propagation time changes greatly and takes an abnormal value. Therefore, the suitability of the pulse wave waveform can be determined by using the amplitude differential element.

  Next, an example of the interval differential element will be described with reference to FIG. FIG. 4 is a diagram showing the relationship between the interval differential element and the pulse wave propagation time. In FIG. 4, the pulse propagation time is shown on the left vertical axis, and the value of the interval differential element is shown on the right vertical axis. The horizontal axis is time. In FIG. 4, the black triangle mark indicates the pulse wave propagation time, the white square mark indicates the interval differential element of the first pulse wave waveform, and the white circle mark indicates the interval differential element of the second pulse wave waveform. As shown in FIG. 4, when the two interval differential elements show approximately constant values, the pulse wave propagation time does not change greatly. However, it can be seen that if any one of the differential elements changes greatly, the pulse wave propagation time changes greatly and takes an abnormal value. Therefore, the suitability of the pulse wave waveform can be determined by using the interval differential element.

  Furthermore, an example of the interval maximum element will be described with reference to FIG. FIG. 4 is a diagram showing the relationship between the interval maximum element and the pulse wave propagation time. In FIG. 4, the pulse propagation time is shown on the left vertical axis, and the value of the interval maximum element is shown on the right vertical axis. The horizontal axis is time. In FIG. 4, the black triangle mark indicates the pulse wave propagation time, the white square mark indicates the interval maximum element of the first pulse wave waveform, and the white circle mark indicates the interval maximum element of the second pulse wave waveform. As shown in FIG. 4, when the two interval maximum elements show a substantially constant value, the pulse wave propagation time does not change greatly. However, it can be seen that if any one of the interval maxima changes greatly, the pulse wave propagation time changes greatly and takes an abnormal value. Therefore, the suitability of the pulse wave waveform can be determined by using the interval maximum element.

  In addition, the suitability determination element may be a ratio of the above-described amplitude differential element, interval differential element, and interval maximum element (hereinafter referred to as appropriateness determination element) of the first pulse wave waveform and the second pulse wave waveform. . The advantages of using the ratio will be described with reference to FIGS.

  First, FIG. 4 is a diagram showing a case where the suitability determination elements of the first pulse wave waveform and the second pulse wave waveform change in the same direction. In FIG. 5, white circles indicate the suitability determination element of the first pulse wave waveform, and black square marks indicate the suitability determination element of the second pulse wave waveform. The black triangle mark indicates the ratio between the appropriateness determining element of the first pulse wave waveform and the appropriateness determining element of the second pulse wave waveform. Moreover, a broken line and a dashed-dotted line show the range where each element is determined to be appropriate.

  In FIG. 4, the point 401 of the appropriateness determination element of the second pulse waveform and the point 402 of the appropriateness determination element of the first pulse waveform are out of the range determined to be appropriate. However, when the suitability determination element changes in the same direction as in the point 401 and the point 402, it is considered that each suitability determination element has changed in the same manner because the state of the blood vessel has changed. Therefore, in this case, it is not preferable to make the points 401 and 402 inappropriate. Therefore, when the ratio between the appropriateness determining element of the first pulse wave waveform and the appropriateness determining element of the second pulse wave waveform is obtained, the ratio does not change when the same changes in the same direction. The point 403 corresponding to the ratio is in a range determined to be appropriate.

  Therefore, it is possible to determine that the ratio is appropriate if it is inappropriate if the appropriateness of the pulse wave is determined only by the appropriateness determination element, even though the waveform is appropriate. It is possible to determine whether the pulse waveform is appropriate.

  Next, FIG. 5 is a diagram showing a case where the propriety determination elements of the first pulse wave waveform and the second pulse wave waveform change in opposite directions. In FIG. 5, white circles indicate the appropriateness determination elements for the first pulse wave waveform, and black square marks indicate the appropriateness determination elements for the second pulse wave waveform. The black triangle mark indicates the ratio between the appropriateness determining element of the first pulse wave waveform and the appropriateness determining element of the second pulse wave waveform. Moreover, a broken line and a dashed-dotted line show the range where each element is determined to be appropriate.

  In FIG. 5, the point 501 of the appropriateness determination element of the second pulse wave waveform and the point 502 of the appropriateness determination element of the first pulse wave waveform exist within the range determined to be appropriate. However, when the suitability determination element changes in the opposite direction as in points 501 and 502, it is considered that the suitability determination elements have changed due to the influence of body movement, etc., rather than the change in the blood vessel state. . Therefore, in this case, it is not preferable to determine the points 501 and 502 as appropriate. Therefore, when the ratio between the appropriateness determining element of the first pulse wave waveform and the appropriateness determining element of the second pulse wave waveform is obtained, the ratio changes greatly when it changes in the opposite direction, so the ratio between the points 501 and 502 The point 503 corresponding to is out of the range determined to be appropriate.

  Therefore, when the suitability of the pulse wave is determined only by the suitability determination element, even though it is an inappropriate pulse waveform, it can be determined to be inappropriate by using the ratio when it is appropriate. It is possible to determine whether the pulse waveform is appropriate.

  The pulse wave velocity calculating unit 44 calculates the pulse wave velocity using the pulse wave waveform determined to be appropriate by the waveform suitability determining unit 43. Specifically, both the first pulse wave waveform of the pulse wave detected by the first pulse wave sensor 11 and the second pulse wave waveform of the pulse wave detected by the second pulse wave sensor 12 are both determined as appropriate. If it is determined as appropriate by the unit 43, the pulse wave propagation time is calculated from the first pulse wave waveform and the second pulse wave waveform determined as appropriate.

  The pulse wave propagation time calculation method is performed by determining a pulse wave velocity calculation reference point in two pulse wave waveforms and calculating a time difference between the reference points. Examples of the pulse wave velocity calculation reference include a rising point (minimum point) of the pulse wave and a point when the height is 1/5 of the pulse wave amplitude.

  Then, the pulse wave velocity is calculated by dividing the distance between the first pulse wave sensor 11 and the second pulse wave sensor 12 by the calculated pulse wave propagation time. Then, the calculated pulse wave propagation velocity is transmitted to the display control unit 45.

  The display control unit 45 displays the acquired information on the display unit 15. Specifically, when the wearing condition determination result is acquired from the wearing quality determination unit 46, the wearing condition determination result is displayed on the display unit 15. Further, when the determination result of the pulse waveform is acquired from the waveform suitability determination unit 43, the determination result is displayed on the display unit 15. Further, when the pulse wave velocity is acquired from the pulse wave velocity calculator 44, the pulse wave velocity is displayed on the display unit 15.

  Next, the flow of processing in the pulse wave velocity calculation device 1 will be described with reference to FIG. FIG. 6 is a flowchart showing a processing flow of the pulse wave velocity calculation apparatus 1. As shown in FIG. 6, in the pulse wave velocity calculation device 1, first, the suitability range reference value setting unit 42 performs an initial setting process of the range reference value of the pulse wave waveform (S100). The range reference value initial setting process will be described later. When the initial setting of the range reference value is completed, the waveform suitability determination unit 43 performs a pulse wave waveform suitability determination process using the set range reference value (S200, waveform determination step). The suitability determination process of the pulse wave waveform will be described later. When the suitability determination process ends, the suitability range reference value setting unit 42 performs a range reference value update process using the suitability determination element of the pulse waveform determined by the waveform suitability determination unit 43 (S300). . The range reference value update process will be described later. Then, the pulse wave velocity calculating unit 44 calculates the pulse wave velocity using the pulse wave waveform determined to be appropriate by the waveform suitability determining unit 43 (S400, pulse wave velocity calculating step), and the display unit 15 calculates. The transmitted pulse wave velocity is displayed (S500). Then, the process returns to step S200. This is the end of the process flow of the pulse wave velocity calculation device 1.

  Next, the flow of the range reference value initial setting process will be described with reference to FIG. FIG. 7 is a flowchart showing the flow of the range reference value initial setting process.

  First, the pulse wave data acquisition unit 41 acquires a pulse wave waveform for one beat (calculation period) of the pulse wave detected by the first pulse wave sensor 11 and the second pulse wave sensor 12 (S101). Next, the suitability range reference value setting unit 42 is a first pulse wave waveform that is a pulse wave waveform detected by the first pulse wave sensor 11 and a pulse wave waveform that is detected by the second pulse wave sensor 12. The pulse wave interval of each second pulse wave waveform is calculated (S102). The pulse wave interval is the time between adjacent local minimum points in the pulse wave waveform.

  Then, it is determined whether the ratio of the calculated pulse wave interval of the first pulse wave waveform to the pulse wave interval of the second pulse wave waveform is within a predetermined range (for example, 0.95 to 1.05) ( S103). The pulse wave interval is synchronized with the heartbeat, and normally, the pulse wave interval of the first pulse wave waveform and the pulse wave interval of the second pulse wave waveform are substantially equal. Accordingly, if the ratio of the pulse wave interval of the first pulse wave waveform to the pulse wave interval of the second pulse wave waveform does not fall within a predetermined range, the pulse wave per beat is accurately determined due to the influence of body movement or the like. It can be determined that it has not been detected.

  If the ratio of the pulse wave interval of the first pulse wave waveform to the pulse wave interval of the second pulse wave waveform is not within the predetermined range (NO in S103), the suitability range reference value setting unit 42 sets the number of measurement errors. It is incremented by 1 and stored in the storage unit 13 (S104). Then, it is determined whether or not the number of measurement errors exceeds a predetermined number (for example, 5 times) (S107), and if it does not exceed the predetermined number (NO in S107), the process returns to step S101. On the other hand, if the predetermined number of times has been exceeded (YES in S107), the wearing quality determination unit 46 determines that the first pulse wave sensor 11 or the second pulse wave sensor 12 is worn and the display unit 15 is worn. A specific error is displayed (S114). And it will be in the state which waits for the 1st pulse wave sensor 11 and the 2nd pulse wave sensor 12 to be reattached (S116).

  On the other hand, if the ratio of the pulse wave interval of the first pulse wave waveform to the pulse wave interval of the second pulse wave waveform is within a predetermined range (YES in S103), each of the first pulse wave waveform and the second pulse wave waveform A suitability determination element is calculated (S105). As described above, the suitability determination element is at least one of an amplitude differential element (D / P), an interval differential element (DT / PT), and an interval maximum element (UT / PT). Moreover, the ratio of each said element may be sufficient. Then, the suitability determination element calculated for each of the first pulse wave waveform and the second pulse wave waveform is within a predetermined range (for example, 0.2 to 0.6 in the case of the amplitude differential element, and 0. 03 to 0.1, and in the case of the interval maximum element, 0.1 to 0.25) is determined (S106).

  If the suitability determination element is not within the predetermined range (NO in S106), the process proceeds to step 104, where the number of measurement errors is incremented by 1 and stored in the storage unit 13. On the other hand, if the suitability determination element is within the predetermined range (YES in S106), the calculated suitability determination element is stored in the storage unit 13 and the number of measurements is incremented by 1 (S108).

  Then, the suitability range reference value setting unit 42 determines whether or not the measured beat number exceeds a predetermined beat number (for example, 20 beats, the first detection period) (S109). If the measured beat number does not exceed the predetermined beat number (NO in S109), the process returns to step S101. On the other hand, if the measured number of beats exceeds the predetermined number of beats (YES in S109), the variance corresponding to the predetermined number of beats of the suitability determining element for each of the first pulse wave waveform and the second pulse wave waveform is calculated (S110). Then, it is determined whether or not the calculated variance is equal to or less than a predetermined value (for example, 0.02 in the case of an amplitude differential element, 0.005 in the case of an interval differential element, and 0.01 in the case of an interval maximum element). (S111). If the variance is larger than the predetermined value (NO in S111), the display unit 15 displays a wearing condition error (S114). This is because when the variance is larger than the predetermined value, it can be determined that the pulse wave waveform is not stable, that is, the first pulse wave sensor 11 or the second pulse wave sensor 12 is worn. Then, it waits for the pulse wave waveform to be acquired again (S116), and the range reference value initial setting process is performed from the beginning.

  On the other hand, if the variance is equal to or less than the predetermined value (YES in S111), the display unit 15 displays the wearing condition of the first pulse wave sensor 11 and the second pulse wave sensor 12 as good (S112).

  Then, the suitability range reference value setting unit 42 calculates an average value of suitability determination elements having a predetermined number of beats stored (S113), and sets the calculated average value as an initial value of the range reference value. This completes the range reference value initial setting process.

  In addition, when determining the wearing condition of the 1st pulse wave sensor 11 and the 2nd pulse wave sensor 12, you may use the sensor (for example, acceleration sensor) which detects a well-known body motion. By using the body motion sensor, it is possible to determine the wearing state of the first pulse wave sensor 11 and the second pulse wave sensor 12 with higher accuracy. This is because the pulse wave obtained from a living body is easily affected by body movement, and therefore it is possible to clarify whether the disturbance of the pulse wave is caused by the wearing condition or the body movement.

  Next, the flow of the pulse wave waveform suitability determination process will be described with reference to FIG. FIG. 8 is a flowchart showing the flow of the pulse wave waveform suitability determination process. First, the waveform suitability determination unit 43 obtains, from the pulse wave data acquisition unit 41, one pulse (calculation period) of the pulse wave waveform that is the waveform of the pulse wave detected by the first pulse wave sensor 11 and the second pulse wave sensor 12. Obtain (S201, pulse waveform acquisition step). Then, from the acquired pulse wave waveform, the same suitability determination element as the process in step S105 of FIG. 7 is calculated (S202). Next, the waveform suitability determination unit 43 determines whether or not the calculated suitability determination element falls within a range of ± X% (for example, ± 10%, range determination value) of the range reference value (S203).

  Note that the above ranges are the first range when the amplitude differential element is used, the fourth range when the ratio of the amplitude differential element is used, and the second range when the interval differential element is used. The fifth range is obtained when the ratio of the range and the interval differential element is used, the third range is obtained when the interval maximum element is used, and the sixth range is obtained when the ratio of the interval maximum element is used.

  If the suitability determination element is within a range of ± X% of the range reference value (YES in S203), it is determined as a pulse wave waveform suitable for pulse wave velocity calculation, and the result is sent to the pulse wave velocity calculator 44. At the same time, the calculated suitability determination element is stored in the storage unit 13 (S204). On the other hand, if the suitability determination element is not within the range of ± X% of the range reference value (NO in S203), it is determined that the pulse wave waveform is not suitable for pulse wave velocity calculation, and is suitable for pulse wave velocity calculation. It is determined whether the period determined not to be a pulse wave waveform exceeds a predetermined period (for example, 5 minutes) (S205). If the predetermined time is exceeded (YES in S205), the display unit 15 displays an error message indicating how the first pulse wave sensor 11 or the second pulse wave sensor 12 is mounted (S206). Then, it waits for the pulse waveform to be acquired again (S207), and the range reference value initial setting process is performed from the beginning.

  On the other hand, if the predetermined time has not been exceeded (NO in S205), the process returns to step S201, and the pulse wave waveform for the next one beat is acquired. The flow of the pulse wave waveform suitability determination process is thus completed.

  Next, the flow of the range reference value update process will be described with reference to FIG. FIG. 9 is a flowchart showing the flow of the range reference value update process.

  First, the suitability range reference value setting unit 42 stores the waveform suitability determination unit 43 in a predetermined period (for example, the second detection period for 20 seconds) immediately before the waveform suitability determination unit 43 determines that it is appropriate. The average value of the suitability determination elements stored in 13 is calculated. Then, the calculated average value is updated as a range reference value (S302).

  A blood pressure measurement device 2 that further includes a blood pressure value estimation unit 61 that estimates a blood pressure from the pulse wave propagation velocity with respect to the pulse wave propagation velocity calculation device 1 will be described with reference to FIGS. 10 and 11.

  FIG. 10 is a block diagram showing a main configuration of the blood pressure measurement device 2 according to the present embodiment. The blood pressure value estimation unit 61 acquires the pulse wave propagation speed calculated by the pulse wave propagation speed calculation unit 44 and estimates the blood pressure value from the acquired pulse wave propagation speed. Then, the estimated blood pressure value is transmitted to the display control unit 45.

  Here, a method for estimating the blood pressure value from the pulse wave velocity will be described.

  The pulse wave velocity (PWV) is represented by the following Moens-Korteweg equation. PWV = (Eh / ρD) 1/2. Here, E is the elastic modulus, h is the blood vessel wall diameter, ρ is the blood density, and D is the blood vessel diameter. Therefore, the pulse wave propagation speed becomes faster as the blood vessel becomes harder and the blood vessel wall becomes thicker. Further, the pulse wave propagation speed increases as the blood vessel inner diameter decreases and the blood density decreases.

  It is also known that blood vessels become harder as blood pressure increases. The higher the blood pressure, the greater the blood vessel wall tension, and the harder the blood vessels. Therefore, when the blood pressure increases, the pulse wave propagation speed also increases.

  And there is a relationship as shown in the following equation between the pulse wave velocity (PWV) and the blood pressure value (BP). BP = a × PWV + b. Here, the inclination a and the intercept b have individual differences. Moreover, even if it is the same person, it changes with the state of the blood vessel of the day. Therefore, the inclination a and the intercept b are determined by obtaining the relationship between the blood pressure value and the pulse wave velocity in advance.

  Therefore, if the slope a and the intercept b are determined in advance, the blood pressure value can be estimated from the pulse wave velocity.

  Next, the flow of processing in the blood pressure measurement device 2 will be described with reference to FIG. FIG. 11 is a flowchart showing a process flow in the blood pressure measurement device 2. In FIG. 11, Steps S100 to S400 are the same as those in FIG.

  When the pulse wave propagation speed is calculated in step S400, the blood pressure value estimation unit 61 estimates the blood pressure value from the preset relationship between the pulse wave propagation speed and the blood pressure value using the calculated pulse wave propagation speed (S600). ). Then, the display unit 15 displays the blood pressure value estimated by the blood pressure value estimation unit 61 (S700). This is the end of the process flow in the blood pressure measurement device 2.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

  Finally, each block of the pulse wave velocity calculation device 1 and the blood pressure measurement device 2, particularly the pulse wave data acquisition unit 41, the suitability range reference value setting unit 42, the waveform suitability determination unit 43, the pulse wave velocity calculation unit 44, the display The control unit 45, the wearing quality determination unit 46, and the blood pressure value estimation unit 61 may be configured by hardware logic, or may be realized by software using a CPU (central processing unit) as follows.

  In other words, the pulse wave velocity calculation device 1 and the blood pressure measurement device 2 include a CPU that executes instructions of a control program that realizes each function, a ROM (read only memory) that stores the program, and a RAM (random) that expands the program. access memory), a storage device (recording medium) such as a memory for storing the program and various data. An object of the present invention is to provide program codes (execution format program, intermediate code program, source program) of control programs for the pulse wave velocity calculation device 1 and the blood pressure measurement device 2, which are software for realizing the functions described above, on a computer. The readable recording medium is supplied to the pulse wave velocity calculation device 1 and the blood pressure measurement device 2, and the computer (or CPU or MPU (microprocessor unit)) stores the program code recorded on the recording medium. This can also be achieved by executing reading.

  Examples of the recording medium include a tape system such as a magnetic tape and a cassette tape, a magnetic disk such as a floppy (registered trademark) disk / hard disk, a CD-ROM (compact disc read-only memory) / MO (magneto-optical) / Disk systems including optical disks such as MD (Mini Disc) / DVD (digital versatile disk) / CD-R (CD Recordable), card systems such as IC cards (including memory cards) / optical cards, or mask ROM / EPROM ( An erasable programmable read-only memory) / EEPROM (electrically erasable and programmable read-only memory) / semiconductor memory system such as a flash ROM can be used.

  Further, the pulse wave velocity calculating device 1 and the second pulse wave sensor 12 may be configured to be connectable to a communication network, and the program code may be supplied via the communication network. The communication network is not particularly limited. For example, the Internet, intranet, extranet, LAN (local area network), ISDN (integrated services digital network), VAN (value-added network), CATV (community antenna television) communication. A network, a virtual private network, a telephone line network, a mobile communication network, a satellite communication network, etc. can be used. In addition, the transmission medium constituting the communication network is not particularly limited. For example, IEEE (institute of electrical and electronic engineers) 1394, USB, power line carrier, cable TV line, telephone line, ADSL (asynchronous digital subscriber loop) line Wireless such as IrDA (infrared data association) and remote control such as remote control, Bluetooth (registered trademark), 802.11 wireless, HDR (high data rate), mobile phone network, satellite line, terrestrial digital network, etc. But it is available. The present invention can also be realized in the form of a computer data signal embedded in a carrier wave in which the program code is embodied by electronic transmission.

  Regardless of the measurement distance of the pulse wave sensor, the pulse wave propagation speed can be accurately calculated, which is suitable for a pulse wave propagation speed calculation apparatus that can freely determine the mounting site of the pulse wave sensor. Further, it is suitable for a device that estimates blood pressure from the pulse wave velocity, for example, a blood pressure measuring device in which a pulse wave sensor is attached to the wrist and fingertip.

DESCRIPTION OF SYMBOLS 1 Pulse wave propagation velocity calculation apparatus 11 1st pulse wave sensor (pulse wave detection part)
12 Second pulse wave sensor (pulse wave detector)
41 Pulse wave data acquisition unit (pulse wave waveform acquisition means)
42 Appropriate range reference value setting unit (range setting means)
43 Waveform suitability determination unit (waveform determination means, range setting means)
44 Pulse wave velocity calculation unit (Pulse wave velocity calculation means)

Claims (18)

In a pulse wave propagation velocity calculation device for calculating a pulse wave propagation velocity using a pulse wave waveform of a pulse wave detected from at least two locations of one living body,
Pulse wave waveform acquisition means for acquiring a part of the same calculation period from each pulse wave waveform detected from a plurality of locations of one living body;
Waveform determination means for determining whether or not each pulse wave waveform of the calculation period acquired by the pulse wave waveform acquisition means can be used for calculation of the pulse wave propagation velocity;
Pulse wave velocity calculating means for calculating the pulse wave velocity using at least two pulse wave waveforms out of the pulse wave waveforms determined by the waveform determining means to be usable for calculating the pulse wave velocity. A pulse wave velocity calculation device.   The waveform determination means uses a point of the pulse wave waveform at a time when the differential waveform obtained by differentiating the pulse wave waveform becomes a maximum point as a differential maximum point, from a minimum point of the pulse wave waveform with respect to the amplitude of the pulse wave waveform. An amplitude differential element that is a ratio of displacement from the local minimum point to the differential maximum point is obtained, and when the amplitude differential element is in the first range, the pulse waveform can be used for calculating the pulse wave propagation velocity. The pulse wave velocity calculation device according to claim 1, wherein   The waveform determining means uses the point of the pulse waveform at the time when the differential waveform obtained by differentiating the pulse waveform becomes a maximum point as a differential maximum point, and the adjacent to the time between adjacent minimum points of the pulse waveform An interval differential element, which is a ratio of time from a previous minimum point to a differential maximum point next to the minimum point, and when the interval differential element is in the second range, the pulse wave 2. The pulse wave velocity calculating apparatus according to claim 1, wherein the waveform is determined to be usable for calculating the pulse wave velocity. A pulse wave detector that is mounted on the living body and detects the pulse wave from the living body;
From the pulse wave waveform of the pulse wave detected by the pulse wave detection unit in the first detection period after the pulse wave detection unit is mounted on the living body, the amplitude differential element for each calculation period is obtained and obtained. A first upper limit obtained by adding the range determination value to the average value from a first lower limit value obtained by calculating an average value of the amplitude differential element in the first detection period and subtracting a predetermined range determination value from the average value. The pulse wave velocity calculation device according to claim 2, further comprising range setting means for setting the first range up to a value. A pulse wave detector that is mounted on the living body and detects the pulse wave from the living body;
The interval differential element for each calculation period is obtained from the pulse wave waveform of the pulse wave detected by the pulse wave detection unit in the first detection period after the pulse wave detection unit is attached to the living body. A second upper limit obtained by calculating an average value of the interval differential element in the first detection period and adding the range determination value to the average value from a second lower limit value obtained by subtracting a predetermined range determination value from the average value. The pulse wave velocity calculation device according to claim 3, further comprising range setting means for setting the second range up to a value. A pulse wave detector that is mounted on the living body and detects the pulse wave from the living body;
The amplitude differential element for each calculation period is obtained from the pulse wave waveform of the pulse wave detected by the pulse wave detection unit in the second detection period immediately before the waveform determination means determines the pulse wave waveform. A third upper limit obtained by calculating an average value of the amplitude differential element in the second detection period and adding the range determination value to the average value from a third lower limit value obtained by subtracting a predetermined range determination value from the average value. The pulse wave velocity calculation device according to claim 2, further comprising range setting means for setting the first range up to a value. A pulse wave detector that is mounted on the living body and detects the pulse wave from the living body;
From the pulse wave waveform of the pulse wave detected by the pulse wave detection unit in the second detection period immediately before the waveform determination means determines the pulse wave waveform, the interval differential element for each calculation period is obtained and obtained. A fourth upper limit obtained by calculating an average value of the interval differential element in the second detection period and adding the range determination value to the average value from a fourth lower limit value obtained by subtracting a predetermined range determination value from the average value. The pulse wave velocity calculation device according to claim 3, further comprising range setting means for setting the second range up to a value. The waveform determination means obtains the point of the pulse wave waveform at the time when the differential waveform obtained by differentiating the pulse wave waveform becomes the maximum point with respect to the two pulse wave waveforms in the calculation period acquired by the pulse wave waveform acquisition means. As the differential maximum point, an amplitude differential element that is a ratio of displacement from the minimum point of the pulse waveform to the next differential maximum point of the minimum relative to the amplitude of the pulse waveform is obtained, and the two pulse waveforms When the ratio of the amplitude derivative element is within the third range, it is determined that the two pulse wave waveforms can be used for calculation of the pulse wave velocity,
The pulse wave velocity calculating means calculates the pulse wave velocity using two pulse wave waveforms determined by the waveform determining means to be usable for calculating the pulse wave velocity. Item 2. The pulse wave velocity calculation device according to Item 1. The waveform determination means obtains the point of the pulse wave waveform at the time when the differential waveform obtained by differentiating the pulse wave waveform becomes the maximum point with respect to the two pulse wave waveforms in the calculation period acquired by the pulse wave waveform acquisition means. As a differential maximum point, an interval that is a ratio of the time from the previous minimum point of the adjacent minimum points to the differential maximum point next to the minimum point with respect to the time between adjacent minimum points of the pulse waveform A differential element is obtained, and when the ratio of the interval differential element between the two pulse wave waveforms is in the fourth range, it is determined that the two pulse wave waveforms can be used for calculation of the pulse wave velocity,
The pulse wave velocity calculating means calculates the pulse wave velocity using two pulse wave waveforms determined by the waveform determining means to be usable for calculating the pulse wave velocity. Item 2. The pulse wave velocity calculation device according to Item 1. Two pulse wave detectors mounted on the living body and detecting pulse waves from the living body;
The amplitude differential for each calculation period of the pulse waveform of each pulse wave detected by the two pulse wave detection units in the first detection period after both of the two pulse wave detection units are mounted on the living body. An element ratio is obtained, an average value of the obtained amplitude differential element ratio in the first detection period is obtained, and a fifth range lower limit value obtained by subtracting a predetermined range determination value from the average value is set to the average value. 9. The pulse wave velocity calculation device according to claim 8, further comprising range setting means for setting the third range up to a fifth upper limit value obtained by adding the range determination value. Two pulse wave detectors mounted on the living body and detecting pulse waves from the living body;
The interval differential for each calculation period of the pulse waveform of each pulse wave detected by the two pulse wave detection units in the first detection period after both of the two pulse wave detection units are mounted on the living body. An element ratio is obtained, an average value of the obtained interval differential element ratio in the first detection period is obtained, and from a sixth lower limit value obtained by subtracting a predetermined range determination value from the average value, the average value is added to the average value. 10. The pulse wave velocity calculation device according to claim 9, further comprising range setting means for setting the fourth range up to a sixth upper limit value obtained by adding the range determination value. Two pulse wave detectors mounted on the living body and detecting pulse waves from the living body;
The ratio of the amplitude differential element for each calculation period of the pulse waveform of each pulse wave detected by the two pulse wave detectors in the second detection period immediately before the waveform determination means determines the pulse waveform. And obtaining an average value of the ratio of the obtained amplitude differential elements in the second detection period, and subtracting a predetermined range decision value from the average value, and the range decision value is added to the average value. The pulse wave velocity calculation device according to claim 8, further comprising: range setting means for setting the third range up to a seventh upper limit value obtained by adding Two pulse wave detectors mounted on the living body and detecting pulse waves from the living body;
The ratio of the interval differential element for each calculation period of the pulse waveform of each pulse wave detected by the two pulse wave detectors in the second detection period immediately before the waveform determination means determines the pulse waveform. And obtaining an average value in the second detection period of the ratio of the obtained interval differential elements, and subtracting a predetermined range decision value from the average value, and the range decision value is added to the average value. The pulse wave velocity calculation device according to claim 9, further comprising: a range setting unit that sets the fourth range up to an eighth upper limit value obtained by adding.   When the waveform determination means determines that any one of the pulse wave waveforms acquired by the pulse wave waveform acquisition means cannot be used for calculating the pulse wave propagation velocity, the waveform determination means includes a presentation means for presenting a determination result. The pulse wave velocity calculation device according to any one of claims 1 to 13. The pulse wave velocity calculation device according to any one of claims 1 to 14,
A blood pressure measurement device, comprising: a blood pressure value estimation unit that estimates a blood pressure value using the pulse wave propagation velocity calculated by the pulse wave propagation velocity calculation device.   A pulse wave velocity calculation device control program for operating the pulse wave velocity calculation device according to any one of claims 1 to 14, wherein the pulse wave velocity velocity calculation for causing a computer to function as each of the above means is provided. Device control program.   The computer-readable recording medium which recorded the pulse wave velocity calculation apparatus control program of Claim 16. A control method of a pulse wave velocity calculation device for calculating a pulse wave velocity using pulse wave waveforms of pulse waves detected from at least two locations of one living body,
A pulse waveform acquisition step of acquiring a portion of the same period from each pulse waveform detected from a plurality of locations of one living body;
A waveform determination step for determining whether or not each pulse wave waveform of the period acquired in the pulse wave waveform acquisition step can be used for calculating a pulse wave propagation velocity;
A pulse wave velocity calculating step for calculating a pulse wave velocity using at least two of the pulse wave waveforms determined to be usable for calculating the pulse wave velocity in the waveform determining step. A control method for a pulse wave velocity calculating device.

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