JP6137895B2 - Sphygmomanometer - Google Patents

Description

  The present invention relates to a sphygmomanometer.

  In a typical upper arm type sphygmomanometer, a blood pressure value is measured by winding a cuff (arm band) around the arm, sending air into the cuff and pressurizing the cuff. In such an upper arm type blood pressure monitor, it is assumed that measurement is performed with a bare arm, but there are circumstances in which it is desired to measure without wearing a sleeve while wearing clothes in a low temperature environment in winter. Therefore, a sphygmomanometer is known which can be measured by wrapping a cuff on the sleeve of clothes.

  Patent Document 1 describes a blood pressure measurement device that can improve measurement accuracy when blood pressure is measured while wearing clothes. This sphygmomanometer stores in advance parameters for calculating a blood pressure value from a measurement value in a clothing state from a measurement value in a state where clothes are removed from a measurement site and a measurement value in the clothing state. . When the clothing mode is selected with a button during blood pressure measurement, the blood pressure value is calculated using the parameters stored for the measurement value.

  Patent Literature 2 discloses a blood pressure calculation unit that calculates a blood pressure based on the pressure in the cuff by winding a cuff that is supplied with air and expands around the measurement site, and a first surface that is in contact with the inner surface of the cuff and on the surface side of the measurement site. A thickness detecting unit for measuring a distance between the inner surface of the first inner surface and a second inner surface that is the inner surface and faces the first inner surface, and a thickness is detected after a certain amount of air is supplied and confined to the cuff during winding. An electronic sphygmomanometer comprising a winding determination unit that detects a winding state by comparing a value of a measurement distance output from a unit with a value indicating a state in which the cuff is optimally wound around a measurement site Has been.

  Patent Document 3 discloses a cuff that is wound around a measurement site of a living body and expands when air is supplied, a sensor that measures the internal pressure of the cuff, and a blood pressure / pulse that calculates blood pressure based on the internal pressure measured by the sensor. A measurement condition detecting unit for detecting whether or not clothes are interposed between the living body and the cuff based on the cuff pressure detected at the measurement site where the cuff is wound when calculating the blood pressure, and blood pressure / pulse An electronic sphygmomanometer is described that includes a notification unit that notifies the data calculated by the calculation unit and the detection result by the measurement condition detection unit.

Japanese Patent No. 4730332 JP 2009-297353 A JP 2010-017334 A

  For example, in the case of a thin shirt, it is considered that there is little error even when measuring with a cuff wrapped around the clothes. However, what kind of clothes can be measured from above is a subjective judgment for the user. It is difficult for the user to determine whether or not his / her clothes are clothes that can accurately measure blood pressure.

  Although it is conceivable to determine the presence or absence of clothes by detecting the thickness of clothes, the influence on blood pressure measurement differs depending on the material of the clothes even at the same thickness. For this reason, in practice, it is not possible to determine whether or not measurement is possible only by the thickness.

  In view of the above, an object of the present invention is to provide a sphygmomanometer that can more accurately determine whether or not a measurement site is covered with clothes that affect blood pressure measurement, as compared with a case where the measurement part is not provided. And

  The sphygmomanometer according to the present invention includes a pressurizing unit that pressurizes the cuff, a cuff pressure detecting unit that detects pressure in the cuff pressed by the pressurizing unit, and when the cuff is pressurized by the pressurizing unit. The contact pressure detector that detects the contact pressure distribution between the measurement site of the subject and the cuff, and the blood pressure of the subject is appropriately measured according to the contact pressure distribution detected by the contact pressure detector. And a determination unit for determining whether or not.

  In the sphygmomanometer according to the present invention, the determination unit preferably determines whether or not the measurement subject's blood pressure is appropriately measured according to the variation amount of the contact pressure distribution.

  In the sphygmomanometer according to the present invention, as the variation amount, when the cuff is pressurized to the upper pressure limit by the pressurizing unit, the determination unit follows the pressurization and the contact pressure at each point of the contact surface is It is preferable to use the time difference between the time points at which they become maximum.

  In the sphygmomanometer according to the present invention, it is preferable that the determination unit further uses a variation amount of the contact pressure distribution before the pressurization unit pressurizes the cuff as the variation amount.

  In the sphygmomanometer according to the present invention, it is preferable that the determination unit further uses a variation amount of the contact pressure distribution after the pressurization unit pressurizes the cuff to the upper pressure limit as the variation amount.

  In the sphygmomanometer according to the present invention, the contact pressure detection unit is preferably a tactile array sensor including a plurality of tactile sensor elements provided on the surface of the cuff in contact with the measurement site of the measurement subject.

  In the sphygmomanometer according to the present invention, it is preferable that the blood pressure monitor further includes a notification unit that notifies the determination result by the determination unit.

  According to the present invention, it is possible to provide a sphygmomanometer that can more accurately determine whether or not the measurement site is covered with clothing that affects blood pressure measurement, as compared with the case where the configuration is not provided. become.

1 is a perspective view of a blood pressure monitor 10. FIG. It is a figure for demonstrating the influence which clothing has on blood pressure measurement. It is the graph which showed the change of the blood pressure measurement value by clothes. It is explanatory drawing of the tactile-array sensor 31. FIG. 1 is a schematic block diagram of a blood pressure monitor 10. FIG. It is the graph which showed typically the time change of the contact pressure detected by each tactile sensor when cuff 50 is pressurized. 4 is a flowchart showing an example of blood pressure measurement by the sphygmomanometer 10; It is a table | surface which shows the data of the experimental result which determines the threshold value of the variation amount of contact pressure distribution. It is the graph which showed the result of having wound the cuff 50 on the sleeve of different clothes about a certain test subject, and measuring the time change of contact pressure distribution.

  Hereinafter, a blood pressure monitor according to the present invention will be described in detail with reference to the accompanying drawings. However, it should be noted that the technical scope of the present invention is not limited to these embodiments, but extends to the invention described in the claims and equivalents thereof.

  FIG. 1 is a perspective view of a sphygmomanometer 10. The sphygmomanometer 10 includes a main body 20, a cuff 50, and an air tube 60. The cuff 50 incorporates an air bag (not shown), and is fixed to, for example, the upper arm of the measurement subject by a predetermined belt. The cuff 50 is connected to the main body 20 by an air pipe 60, and air is fed into the cuff 50 through the air pipe 60. The sphygmomanometer 10 measures the blood pressure of the measurement subject in the process of depressurizing the cuff 50 after pressurizing the cuff 50.

  The main body 20 includes at least a display unit 21 and an operation unit 22. The display unit 21 is composed of, for example, a liquid crystal display panel, and displays numerical values being measured, measurement results of systolic blood pressure values, and systolic blood pressure values. The operation unit 22 includes a switch for instructing start / stop of measurement, a switch for selecting a person to be measured, and the like.

  For example, in an oscillometric sphygmomanometer, a cuff is wound around the arm, air is sent into the cuff to increase the tightening pressure of the arm, and pressurize until the pulse wave from the artery disappears. Thereafter, the blood pressure value is measured from the wave height state between the appearance and disappearance of the pulse wave when the pressure is reduced at a constant flow rate. The oscillometric sphygmomanometer is premised on measurement with a bare arm in order to detect the state of the pulse wave from the artery during pressurization and decompression.

  FIG. 2A and FIG. 2B are diagrams for explaining the influence of clothes on blood pressure measurement. 2A and 2B are schematic views showing a state where the cuff 85 is directly wound around the skin 82 of the arm 81 and a state where the cuff 85 is wound around the arm 81 from above the clothes (sleeves) 84, respectively. FIG. 86 is a cuff material, and 87 is air in the cuff. When the cuff 85 is wound from above the garment 84, a kind of damper action occurs depending on the material of the garment 84, and the propagation of the pulse wave from the artery 83 to the cuff 85 and the pressure distribution in the cuff 85 become non-uniform. For this reason, if the measurement is performed from above the clothes, the accuracy of detecting the pulse wave is degraded, and the blood pressure value tends to be measured higher than when measured with a bare arm.

  FIG. 3 is a graph showing how blood pressure values change when measured from various clothes on subjects whose maximum and minimum blood pressure values are 130 mmHg and 80 mmHg, respectively, when measured with a bare arm. As shown in the figure, when measured from the top of the Y-shirt, the value is not much different from that of a bare arm because it is thin clothes. However, when measured from above a trainer or sweater, the value is higher than when measured with a bare arm due to the thickness of the clothes and the elasticity of the material. Further, when the cuff is wound around the skin with the trainer rolled up, the measurement site itself is a bare arm, but the arm is blocked by rolling up, so the numerical value is also increased.

  As described above, since the generation / disappearance of the pulse wave is changed by the damper effect of the clothes, the upper arm type sphygmomanometer basically measures the measurement by rolling up the sleeves of the clothes and winding the cuff. However, it is normal to wear clothes in the winter, and when the sleeves are rolled up and measured, the blood pressure increases due to the pressure caused by rolling up the sleeves. In addition, blood pressure values change even in a low-temperature environment. Especially in the elderly, it is difficult to take off clothes easily because there is a risk of inducing a stroke or the like due to a rapid temperature change called a heat shock in winter. For this reason, there is a situation where it is desired to measure blood pressure without wearing a sleeve while wearing clothes.

  In a commercially available sphygmomanometer, for example, if it is a thin shirt, it is said that there is little error even if it is measured by wrapping a cuff over clothing. However, it is difficult for the user to determine what kind of clothes can be measured from above the clothes. A sphygmomanometer is also known that detects the thickness of clothes and determines the presence or absence of clothes, but the elasticity varies depending on the material of the clothes even at the same thickness, and the influence on blood pressure measurement differs. For this reason, in practice, it is not possible to determine whether or not measurement is possible only by the thickness.

  Therefore, in the sphygmomanometer 10, a sheet-like tactile array sensor is arranged on the surface of the cuff 50 on the side in contact with the measurement site (skin or clothes) of the measurement subject. Then, when the cuff 50 is pressurized by the tactile array sensor, a change in the contact pressure distribution between the cuff 50 and the measurement site is detected. The degree of variation in the contact pressure distribution reflects the thickness and elasticity of the clothes around which the cuff 50 is wound. For this reason, the sphygmomanometer 10 quantifies the degree of variation so that the blood pressure of the measurement subject can be appropriately measured (that is, the measurement site is not covered with clothing that affects the blood pressure measurement). ) Determine whether.

  4A and 4B are explanatory diagrams of the tactile array sensor 31. FIG. The tactile array sensor 31 includes a plurality of tactile sensors 31A arranged in a lattice pattern, and is arranged on a contact surface with the measurement site of the measurement subject. FIG. 4A shows a diagram in which the tactile array sensor 31 is disposed on the unfolded cuff 50 and a schematic diagram in which the upper surface of the tactile array sensor 31 is enlarged. As an example, the sphygmomanometer 10 uses a tactile array sensor 31 in which a detection area of 16 mm × 16 mm is divided into 42 in a lattice shape and a tactile sensor 31A is arranged in each lattice. Thus, the tactile array sensor 31 only needs to have an area of a certain size that can detect the distribution of contact pressure, and does not necessarily need to cover the entire surface of the cuff 50.

  FIG. 4B is a diagram for explaining the principle that each tactile sensor 31A detects the contact pressure. In each tactile sensor 31A, a capacitor is formed by two electrodes 31B arranged along the surface of the tactile array sensor 31. When the surface of the tactile sensor 31 is pressurized, the distance d between the electrodes 31B of each tactile sensor 31A is reduced, and the capacitance is changed. The sphygmomanometer 10 detects a contact pressure between the measurement site and the cuff 50 by detecting a change in the capacitance of the tactile array sensor 31 and converting it to a pressure.

  FIG. 5 is a schematic block diagram of the sphygmomanometer 10. The main body 20 of the sphygmomanometer 10 includes a display unit 21, an operation unit 22, a pressurizing pump 23, a drive circuit 24, a pressure sensor 25, an oscillation circuit 26, a slow leak valve 27, a drive circuit 28, And a control unit 40. The pressurizing pump 23, the pressure sensor 25, and the slow leak valve 27 are connected by a cuff 50 and an air pipe 60.

  The display unit 21 and the operation unit 22 are as described above with reference to FIG. The display unit 21 displays a message for notifying the user of the possibility of measurement with clothes, together with the measurement result of the blood pressure value. The display unit 21 is an example of a notification unit.

  The pressurizing pump 23 pressurizes the inside of the cuff 50 by sending air into the cuff 50. The pressurizing pump 23 is an example of a pressurizing unit. The drive circuit 24 drives the pressurizing pump 23 based on a control signal given from the control unit 40.

  The pressure sensor 25 is a sensor that detects the pressure in the cuff 50 and converts it into an electrical signal, and outputs a pressure detection signal to the oscillation circuit 26. The pressure in the cuff 50 is the pressure in the air bag provided in the cuff 50. The pressure sensor 25 is an example of a cuff pressure detection unit. The oscillation circuit 26 converts the pressure detection signal acquired from the pressure sensor 25 into a frequency signal and outputs it to the control unit 40. The pressure in the cuff 50 is calculated from this change in frequency.

  The slow leak valve 27 gradually exhausts the air accumulated in the cuff 50. The drive circuit 28 opens and closes the slow leak valve 27 based on a control signal given from the control unit 40.

  The cuff 50 has a tactile array sensor 31, and the main body 20 has a tactile detection circuit 32. The tactile sense detection circuit 32 detects a contact pressure between the measurement site of the measurement subject and the cuff 50 by detecting a change in the capacitance of the tactile array sensor 31 and converting it to a pressure. The tactile array sensor 31 and the tactile detection circuit 32 are an example of a contact pressure detection unit.

  The control unit 40 is configured as a control circuit including a CPU, RAM, ROM, and the like. The control unit 40 includes, as functional blocks, a memory 41, a pressurization control unit 42, a blood pressure value measurement unit 43, an exhaust control unit 44, a display control unit 45, a pressure distribution acquisition unit 46, and a pressure change analysis unit. 47 and a measurement availability determination unit 48.

  The memory 41 stores the measurement value of the measurement subject measured by the blood pressure value measurement unit 43. The pressurization control unit 42 controls the drive circuit 24 to pressurize the cuff 50 until the pressure detected by the pressure sensor 25 reaches a predetermined pressurization upper limit pressure.

  The blood pressure value measuring unit 43 uses, for example, an oscillometric method based on data such as a start pressure value of each pulse wave detected from a change in frequency of the frequency signal generated by the oscillation circuit 26 and a measurement time thereof. Measure the systolic blood pressure and the minimum blood pressure.

  The exhaust control unit 44 controls the exhaust of air in the cuff 50 by the slow leak valve 27. The display control unit 45 causes the display unit 21 to display a message for informing the user of the maximum / minimum blood pressure values measured by the blood pressure value measurement unit 43 and the measurement availability determined by the measurement availability determination unit 48.

  The pressure distribution acquisition unit 46 acquires the distribution of contact pressure on the contact surface between the measurement site of the measurement subject and the cuff 50 detected by the tactile sense detection circuit 32. The distribution of the contact pressure detected when the cuff 50 is pressurized varies depending on the material around which the cuff 50 is wound. When pressure is applied to a completely uniform object, the contact pressure distribution is also uniform. However, when the cuff 50 is wound around the sleeve of the clothes and pressed, the contact pressure distribution varies depending on the material of the clothes. Different.

  The pressure change analysis unit 47 quantifies the degree of variation in the contact pressure distribution acquired by the pressure distribution acquisition unit 46 by paying attention to the following three amounts with reference to FIG.

  FIG. 6 is a graph schematically showing temporal changes in contact pressure detected by each tactile sensor when the cuff 50 is pressurized. Since the output of the capacitance change is different for each tactile sensor constituting the tactile array sensor 31, this graph shows that the contact pressure varies with a certain width depending on the position of each tactile sensor.

  The first amount that the pressure change analysis unit 47 focuses on is the pressure difference ΔP1 that occurs when the cuff 50 is simply wrapped around the measurement site before the pressurization is started. The pressure difference here is a difference between the maximum value and the minimum value of the contact pressure detected by the 42 tactile sensors. For example, when the cuff 50 is wound over woolen yarn such as a sweater, the pressure difference ΔP1 increases because the variation in contact pressure increases depending on the bristle even when no pressure is applied.

  The second amount that the pressure change analysis unit 47 focuses on is the time difference ΔT of the pressure change during pressurization. This time difference ΔT is the time when the contact pressures at the 42 tactile sensors become maximum when the pressurization control unit 42 pressurizes to the pressurization upper limit pressure and stops pressurization. The time difference between the earliest time point and the latest time point. When the cuff 50 is wound on a material having high elasticity, the followability is poor, and the ease of transmission of the influence of pressurization varies depending on the position, so this time difference ΔT increases.

  The third amount that the pressure change analysis unit 47 focuses on is the pressure difference ΔP2 that occurs after the cuff 50 is pressurized to the pressurization upper limit pressure. This pressure difference is also the difference between the maximum value and the minimum value of the contact pressure detected by the 42 tactile sensors, similarly to ΔP1. In particular, with a thick material, the pressure difference ΔP2 at the time of completion of pressurization becomes large.

  The measurement availability determination unit 48 determines whether or not the measurement site is covered with clothes that affect blood pressure measurement according to the variation amounts ΔP1, ΔT, and ΔP2 of the contact pressure distribution quantified by the pressure change analysis unit 47. To do. For example, the measurement availability determination unit 48 sets the threshold values of the variation amounts ΔP1, ΔT, and ΔP2 to 1000 pF, 5 seconds, and 3000 pF, respectively. Note that the contact pressure detected by the tactile array sensor 31 increases with the capacitance of the tactile sensor, and therefore the pressure is expressed in units of capacitance pF (picofarad) for convenience.

  The measurement availability determination unit 48 is configured to accurately measure blood pressure when the measurement subject wears clothes that affect blood pressure measurement on the measurement site when ΔP1 ≧ 1000 pF, ΔT ≧ 5 seconds, and ΔP2 ≧ 3000 pF. Judge that it is not possible. At other times, that is, when ΔP1 <1000 pF, ΔT <5 seconds, or ΔP2 <3000 pF, even if the measurement subject wears clothes on the measurement site, It is determined that blood pressure can be measured while wearing The measurement availability determination unit 48 is an example of a determination unit.

  Next, the operation of blood pressure measurement by the sphygmomanometer 10 will be described. FIG. 7 is a flowchart showing an operation example of blood pressure measurement by the sphygmomanometer 10. The processing flow shown in FIG. 7 is executed by the CPU of the control unit 40 in accordance with a program recorded in advance in the ROM of the control unit 40.

  When measuring the blood pressure, the person to be measured wears the cuff 50 on the wrist, uses the switch of the operation unit 22 to select the person to be measured, and instructs the start of measurement. First, the exhaust control unit 44 closes the slow leak valve 27 so that the cuff 50 can be pressurized (S11).

  Prior to pressurization, the pressure change analysis unit 47 quantifies the pressure difference ΔP1 when no pressure is applied based on the output from the tactile array sensor 31 (S12). Next, the drive circuit 24 is controlled by the pressurization control unit 42, and the inside of the cuff 50 is pressurized to the pressurization upper limit pressure by feeding air into the cuff 50 (S13). When the pressurization is completed, the pressure change analysis unit 47 quantifies the time difference ΔT of the pressure change (S14). Further, the pressure change analysis unit 47 quantifies the pressure difference ΔP2 when the pressurization is completed (S15).

  Then, the measurement availability determination unit 48 determines whether each of the variation amounts ΔP1, ΔT, ΔP2 obtained by the pressure change analysis unit 47 is less than a threshold value (S16). When any of ΔP1, ΔT, and ΔP2 exceeds the threshold value (No in S16), the display control unit 45 displays a message “Accurate measurement cannot be performed because of clothes” on the display unit 21 (S17). ). Then, while the slow leak valve 27 is opened by the exhaust control unit 44 and the cuff 50 is decompressed, the blood pressure value measuring unit 43 measures the blood pressure (S18), and proceeds to S21.

  On the other hand, when the variation amounts ΔP1, ΔT, and ΔP2 are all less than the threshold value (Yes in S16), the blood pressure value measurement unit 43 measures the blood pressure while reducing the cuff 50 without displaying the above message. (S19). In this case, the control unit 40 stores the measurement value in the memory 41 (S20).

  When the blood pressure measurement is completed, the display control unit 45 controls the display unit 21 to display the measurement result (S21). Further, the exhaust control unit 44 opens the slow leak valve 27 and exhausts the air in the cuff 50 rapidly (S22). The blood pressure measurement operation by the sphygmomanometer 10 is thus completed.

  Next, the basis of the above threshold value regarding the variation amount of the contact pressure distribution will be described. The above threshold value is determined based on the result of an experiment in which variation amounts ΔP1, ΔT, and ΔP2 are measured for 10 subjects with bare arms. In this experiment, the tactile array sensor described with reference to FIG. 4A is used. The variation amounts ΔP1, ΔT, and ΔP2 of the outputs from the 42 tactile sensors when cuffing around 10 naked subjects and pressurizing to 0 to 200 mmHg are as shown in FIG. .

  As shown in the figure, the values of variations ΔP1, ΔT, and ΔP2 for 10 subjects are in the ranges of 300 to 710 pF, 1.8 to 3.8 seconds, and 1520 to 2480 pF, respectively. From this result, if each variation amount detected at the time of blood pressure measurement is within these ranges, blood pressure can be measured even if there is an influence of clothing, but if each variation amount exceeds these ranges, It can be said that the accuracy of the measured value cannot be guaranteed due to the influence of the above. Therefore, if the variation amounts ΔP1, ΔT, and ΔP2 are not significantly different from the above experimental results, respectively less than 1000 pF, less than 5 seconds, and less than 3000 pF, even if the cuff is measured on the clothes, It can be said that the same accuracy as that obtained when measuring is obtained. For this reason, the sphygmomanometer 10 sets the threshold value of each variation amount as described above.

  Note that the measurement availability determination unit 48 may determine the measurement availability based only on the time difference ΔT, or the measurement availability based on two of the time difference ΔT and the pressure difference ΔP1, or two of the time difference ΔT and the pressure difference ΔP2. May be determined. However, the time difference ΔT is an essential criterion because blood pressure cannot be measured unless it is within the threshold value. If the time difference ΔT increases, the vibration of the pulse is deformed and propagated to the sphygmomanometer 10, so that the blood pressure value may not be determined. On the other hand, with respect to the pressure differences ΔP1 and ΔP2, blood pressure can be measured even if the pressure difference is out of the threshold value, but the error of the measured value increases. Therefore, the determination as to whether measurement is possible does not necessarily have to be performed for all of the variation amounts ΔP1, ΔT, ΔP2, but it is preferable to perform determination for all three variation amounts ΔP1, ΔT, ΔP2 from the viewpoint of measurement accuracy.

  9 (A) to 9 (C) are graphs showing the results of measuring a change in contact pressure distribution over time by winding a cuff 50 on a shirt, a trainer, and a sweater sleeve for a subject. is there. The horizontal axis of each graph is time (seconds), and the vertical axis is pressure (pF). Similar to the above, the pressure is displayed as the capacitance of the tactile sensor. In each graph, all temporal changes in the outputs of the tactile sensors constituting the tactile array sensor 31 are displayed in an overlapping manner. In the figure, the time difference at which the output of each tactile sensor rises in the portion surrounded by the broken line corresponds to ΔT. Further, the pressure difference indicated by the arrow corresponds to ΔP2. Further, the pressure difference before the output of each tactile sensor rises (to the left of the portion surrounded by the broken line) corresponds to ΔP1.

  FIG. 9A is a graph when the cuff 50 is wound from above the shirt and measured. In this case, the variation amounts quantified by the pressure change analysis unit 47 are ΔP1 = 600 pF, ΔT = 3 seconds, and ΔP2 = 2400 pF. In the case of this shirt, since the contact pressure distribution is relatively uniform and relatively follows the pressure change of the cuff 50, it can be said that it is a clothing material that does not affect blood pressure measurement. Since all the variation amounts are within the above threshold value, in this case, the measurement availability determination unit 48 determines that blood pressure measurement is possible.

  In addition, when the cuff 50 is directly wound on the bare arm (skin) and measured, the same result as in FIG. 9A is obtained. Actually, due to the non-uniform thickness (fat) of the skin, there is some variation in the contact pressure distribution even when not using clothes.

  FIG. 9B is a graph when the cuff 50 is wound from above the trainer and measured. In this case, the variation amounts quantified by the pressure change analysis unit 47 are ΔP1 = 600 pF, ΔT = 12 seconds, and ΔP2 = 3400 pF. In the case of this trainer, the variation in contact pressure is large, and damping occurs when the contact pressure changes with the pressurization of the cuff 50, and the variation in rising between the tactile sensors becomes large. Therefore, it can be said that this trainer is a clothing material that affects blood pressure measurement. Since the time difference ΔT and the pressure difference ΔP2 exceed the above threshold value, in this case, the measurement availability determination unit 48 determines that accurate blood pressure measurement cannot be performed.

  FIG. 9C is a graph when the cuff 50 is wound around the sweater and measured. In this case, the variation amounts quantified by the pressure change analysis unit 47 are ΔP1 = 1800 pF, ΔT = 26 seconds, and ΔP2 = 4000 pF. In the case of this sweater, the contact pressure variation is large, and the delay variation (time difference ΔT) in the pressurizing process of the cuff 50 is large. Since all the variations ΔP1, ΔT, and ΔP2 exceed the threshold value, in this case, the measurement availability determination unit 48 determines that accurate blood pressure measurement cannot be performed.

  By the way, if an inaccurate measurement value when the measurement site is covered with clothes that affect blood pressure measurement is stored, when the user checks the past measurement value stored in the memory 41, the blood pressure There is a risk that fluctuations in value may not be detected correctly. Therefore, as shown in the flow of FIG. 7, the sphygmomanometer 10 may store the measurement value in the memory 41 only when the measurement availability determination unit 48 determines that blood pressure measurement is possible. Similarly, when the measurement value of the sphygmomanometer 10 is stored in an external data collection terminal, the measurement value may be stored only when the measurement availability determination unit 48 determines that blood pressure measurement is possible.

  In the flow of FIG. 7, even when it is determined that accurate blood pressure measurement cannot be performed, the blood pressure value measurement unit 43 measures blood pressure (S18), but when it is determined that measurement is impossible, blood pressure measurement may be stopped. Good. In addition, when it is determined that accurate blood pressure measurement cannot be performed, instead of displaying the message to that effect on the display unit 21 or in addition to that, the fact may be notified to the subject by voice guidance. .

  In the above description, the tactile array sensor 31 has been described in which a contact pressure is detected in accordance with a change in capacitance. However, the tactile array sensor 31 may be of other types. For example, as the tactile array sensor 31, a sensor in which a large number of tactile sensors that detect a contact pressure using a change in contact resistance or a change in the amount of reflected light may be used.

  The blood pressure measurement method using the sphygmomanometer 10 is not limited to the oscillometric method as long as the cuff is fixed to the measurement site of the measurement subject and the blood pressure is measured in the process of depressurization after the cuff is pressurized. Not.

DESCRIPTION OF SYMBOLS 10 Blood pressure monitor 20 Main body 21 Display part 22 Operation part 23 Pressurization pump 25 Pressure sensor 27 Slow leak valve 31 Tactile array sensor 32 Tactile detection circuit 40 Control part 41 Memory 42 Pressure control part 43 Blood pressure value measurement part 44 Exhaust control part 45 Display control unit 46 Pressure distribution acquisition unit 47 Pressure change analysis unit 48 Measurement availability determination unit 50 Cuff 60 Air tube

Claims (5)

A pressurizing part for pressurizing the cuff;
A cuff pressure detector for detecting the pressure in the cuff pressed by the pressurizer,
A contact pressure detection unit that detects a contact pressure distribution between the measurement site of the measurement subject and the cuff when the cuff is pressurized by the pressurization unit;
A determination unit that determines whether blood pressure measurement of the measurement subject is appropriately performed according to a variation amount of the contact pressure distribution detected by the contact pressure detection unit ,
The determination unit follows the pressurization when the cuff is pressurized to the pressurization upper limit pressure as the variation amount at each point on the contact surface between the measurement site and the cuff. Use the time difference between multiple time points where the contact pressure of each becomes maximum,
Blood pressure meter which is characterized a call. The sphygmomanometer according to claim 1 , wherein the determination unit further uses a variation amount of the contact pressure distribution before the pressurization unit pressurizes the cuff as the variation amount. The determination section, as the variation amount, the pressing is further used a variation of the contact pressure distribution after pressurizing the cuff to the pressure upper limit pressure, blood pressure monitor according to claim 1 or 2 . The contact pressure detection portion is provided on the surface of the cuff that contacts the measurement site of the measurement subject, a tactile array sensor including a plurality of tactile sensor elements, any one of claims 1 to 3 The sphygmomanometer described in 1. The determining unit further includes a notification unit for notifying the determination result by the blood pressure monitor according to any one of claims 1-4.

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