Sphygmomanometers, blood pressure measurement methods, and procedures

Abstract

The blood pressure meter of the present invention is a blood pressure meter (100) that temporarily compresses a wrist (210) as a measured part by a blood pressure measurement cuff (10), uses a pressure sensor (62) for detecting the pressure in the cuff, and performs blood pressure measurement using an oscillometric method, wherein the blood pressure meter (100) comprises: a mode operating unit (40) for inputting a mode indication for switching the mode to a nighttime blood pressure measurement mode that automatically starts blood pressure measurement according to a predetermined schedule; a first determination unit (110) for switching to the nighttime blood pressure measurement mode in response to the input of the mode indication, temporarily pressurizing the cuff to a pressure lower than the cuff pressure used for blood pressure measurement, and determining the winding state of the cuff based on the output of the pressure sensor; and a notification unit (30) for notifying the determined winding state of the cuff in response to the determination of the winding state of the cuff.

Description

Technical Field

[0001] The present invention relates to a sphygmomanometer, and more specifically, to a sphygmomanometer having a nighttime (sleep) blood pressure measurement mode. Furthermore, the present invention relates to a blood pressure measurement method for measuring blood pressure using such a sphygmomanometer. Furthermore, the present invention relates to a program for causing a computer to execute such a blood pressure measurement method. Background Art

[0002] In oscillometric blood pressure measurement, in which the blood pressure is measured while the cuff compresses the measured part, it is necessary to properly wrap the cuff around the measured part (upper arm or wrist) in order to perform accurate measurement. For example, if the cuff is loosely wrapped, the pressure of the cuff cannot be accurately transmitted to the artery, making it impossible to perform accurate blood pressure measurement. Therefore, Patent Document 1 discloses a technique for detecting the wrapping strength of the cuff relative to the measured part when the blood pressure measurement start switch is turned on, thereby determining whether the cuff is tightly wrapped around the measured part ("tightly wrapped"), "properly" wrapped around the measured part ("properly wrapped"), or loosely wrapped around the measured part ("loosely wrapped"), and notifying the subject of the determination result.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 5408142

[0006] In the technology of Patent Document 1, after the blood pressure measurement start switch is turned on, a cuff wrapping check is performed immediately before blood pressure measurement begins. If the cuff is not properly wrapped around the measurement site, the subject is notified to rewrap the cuff. If the cuff is properly wrapped around the measurement site, blood pressure measurement begins. Therefore, this technology allows blood pressure measurement to be performed with the cuff properly wrapped, resulting in highly reliable measurement results.

[0007] However, the wrapping determination method described in Patent Document 1 can be applied to normal blood pressure measurements (in other words, blood pressure measurements not performed while the subject is asleep), but cannot be directly applied to blood pressure measurements taken while the subject is asleep, i.e., during nighttime blood pressure measurements, the subject is asleep. Therefore, even if the wrapping determination result is notified to the subject during blood pressure measurement, the subject cannot rewrap the cuff while asleep. Summary of the Invention

[0008] Problems to be solved by the invention

[0009] The present invention has been made to solve the above-mentioned problems, and its object is to provide a sphygmomanometer and a blood pressure measurement method that can accurately measure blood pressure while a subject is sleeping. Furthermore, the present invention is to provide a program for causing a computer to execute such a blood pressure measurement method.

[0010] Means used to solve problems

[0011] In order to achieve the object of the present invention, the blood pressure meter of the present invention temporarily compresses the wrist as the measured part by a blood pressure measurement cuff, uses a pressure sensor to detect the pressure in the cuff, and uses an oscillometric method to measure blood pressure, and is characterized in that:

[0012] The blood pressure monitor has:

[0013] a mode operation unit for inputting a mode instruction for switching the mode between a normal blood pressure measurement mode in which blood pressure measurement is performed according to an input blood pressure measurement instruction and a nighttime blood pressure measurement mode in which blood pressure measurement is automatically started according to a predetermined schedule;

[0014] a first determination unit that switches to the nighttime blood pressure measurement mode in response to input of the mode instruction, temporarily pressurizes the cuff to a pressure lower than the cuff pressure used for the blood pressure measurement, and determines a wrapped state of the cuff based on an output of the pressure sensor; and

[0015] The second determination unit temporarily pressurizes the cuff to a pressure lower than the cuff pressure used for the blood pressure measurement in the normal blood pressure measurement mode before the blood pressure measurement instruction is input and the second determination unit determines the wrapped state of the cuff based on the output of the pressure sensor according to a normal determination criterion that predetermines the degree of the wrapped state of the cuff.

[0016] In the nighttime blood pressure measurement mode, the first determination unit determines the wrapped state of the cuff according to a strict determination criterion in which the degree of the wrapped state of the cuff deviates in a tightening direction compared to the normal determination criterion.

[0017] The blood pressure monitor includes a notification unit configured to notify, upon determining the wrapped state of the cuff, of the determined wrapped state of the cuff.

[0018] In this specification, the "mode operation unit" can be, for example, a switch provided on the main body of the blood pressure monitor, which can accept the switch being turned on by the user as an instruction, or the "mode operation unit" can also be composed of a communication unit that receives instructions from a smartphone or the like outside the blood pressure monitor via wireless communication.

[0019] "Upon switching to the nighttime blood pressure measurement mode" typically refers to the time of switching to the nighttime blood pressure measurement mode, but may also refer to a time period within which the subject is expected to be awake, such as within 5 minutes from that time. Similarly, "Upon determination of the cuff's wrapped state" typically refers to a time period within which the cuff's wrapped state is determined, and may also refer to a time period within which the subject is expected to be awake, such as within 5 minutes from that time.

[0020] The "wrap state of the cuff" indicates whether the cuff is properly wrapped around the measured area. For example, as described in Patent Document 1, this refers to whether the cuff is wrapped tightly around the measured area ("tightly wrapped"), properly wrapped around the measured area ("properly wrapped"), or loosely wrapped around the measured area ("loosely wrapped"). Furthermore, the "degree of wrapping of the cuff" indicates the degree of wrapping from loose wrapping to tight wrapping.

[0021] In the sphygmomanometer of the present invention, in the normal blood pressure measurement mode, before a blood pressure measurement instruction is input and a blood pressure measurement is performed, the second determination unit temporarily pressurizes the cuff to a pressure lower than the cuff pressure used for the blood pressure measurement. Based on the output of the pressure sensor, the second determination unit determines the cuff wrapping state according to a normal determination standard that predetermines the degree of wrapping of the cuff. Following the determination of the cuff wrapping state, the notification unit notifies the subject of the determined cuff wrapping state. This notification allows the subject to determine whether the cuff is properly wrapped around the measured area according to the normal determination standard. Therefore, for example, if the cuff wrapping state is inappropriate according to the normal determination standard and is loosely wrapped ("loosely wrapped"), the subject can rewrap the cuff to a "properly" wrapped state ("properly wrapped"). By performing the blood pressure measurement only when the cuff is "properly wrapped," as in conventional examples, the measurement results obtained in the normal blood pressure measurement mode are highly reliable.

[0022] In the sphygmomanometer of the present invention, for example, a subject inputs a mode instruction through the mode operation unit to switch the mode to a nighttime blood pressure measurement mode in which blood pressure measurement automatically begins according to a predetermined schedule. The sphygmomanometer thereby switches to the nighttime blood pressure measurement mode. In the nighttime blood pressure measurement mode, when the sphygmomanometer automatically begins blood pressure measurement according to the schedule, the subject cannot be expected to change the cuff wrapping position while sleeping. Upon input of the mode instruction, the sphygmomanometer switches to the nighttime blood pressure measurement mode. The first determination unit temporarily pressurizes the cuff to a pressure lower than the cuff pressure used for blood pressure measurement and, based on the output of the pressure sensor, determines the cuff wrapping position according to a strict determination criterion in which the degree of cuff wrapping deviates from the normal determination criterion in a tightening direction. Upon determining the cuff wrapping position, the notification unit notifies the subject of the determined cuff wrapping position. This notification allows the subject to determine whether the cuff is properly wrapped around the measured area according to the strict determination criterion. Therefore, for example, if the winding state of the cuff is inappropriate under the strict judgment standard and the cuff is in a loosely wound state ("loosely wound"), the subject can rewind it to a "properly" wound state ("properly wound"). Then, the sphygmomanometer automatically starts blood pressure measurement according to a predetermined schedule in the nighttime blood pressure measurement mode. As a result, in the nighttime blood pressure measurement mode, blood pressure measurement is performed using the oscillometric method when the winding state of the cuff is appropriate according to the strict judgment standard. Therefore, according to this sphygmomanometer, accurate blood pressure measurement can be performed when the subject's blood pressure is measured while he or she is sleeping.

[0023] In one embodiment of the sphygmomanometer, it is characterized in that:

[0024] The first determination unit determines whether the wrapped state of the cuff is appropriate based on the determined wrapped state of the cuff according to the strict determination criterion.

[0025] The second determination unit determines whether the wrapped state of the cuff is appropriate based on the determined wrapped state of the cuff according to the normal determination criterion.

[0026] The notification unit notifies whether the wrapped state of the cuff is appropriate.

[0027] In this embodiment of the blood pressure monitor, in the normal blood pressure measurement mode, before a blood pressure measurement instruction is input and blood pressure measurement is performed, the second determination unit temporarily pressurizes the cuff to a pressure lower than the cuff pressure used for the blood pressure measurement and, based on the output of the pressure sensor, determines whether the cuff is properly wrapped according to the normal determination criteria. Therefore, as in conventional examples, by performing blood pressure measurement only when the cuff is properly wrapped, the measurement results obtained in the normal blood pressure measurement mode are highly reliable.

[0028] On the other hand, in the sphygmomanometer of this embodiment, the first determination unit determines whether the wound state of the cuff is appropriate based on the strict determination standard in the nighttime blood pressure measurement mode. As described above, as the wound state of the cuff is determined, the notification unit notifies whether the determined wound state of the cuff is appropriate. Through this notification, the subject can recognize whether the cuff is appropriately wound relative to the measured part. Therefore, the subject can change the wound state of the cuff to an extent that the wound state of the cuff is determined to be "appropriate" based on the strict determination standard. Therefore, when the sphygmomanometer automatically starts blood pressure measurement according to the schedule in the nighttime blood pressure measurement mode, it can be expected that the wound state of the cuff is maintained as "appropriate" based on the normal determination standard. Therefore, according to this sphygmomanometer, accurate blood pressure measurement can be performed in the nighttime blood pressure measurement mode.

[0029] In one embodiment of the sphygmomanometer, it is characterized in that:

[0030] This blood pressure monitor includes a control unit configured to deactivate the first determination unit and the notification unit when blood pressure measurement is automatically started according to the schedule in the nighttime blood pressure measurement mode.

[0031] During the phase of switching to the nighttime blood pressure measurement mode and waiting for the scheduled blood pressure measurement, it is expected that the subject is in a sleeping state. Even if the notification unit attempts to make a notification, it is believed that the subject who is in a sleeping state will not notice it. Therefore, in the blood pressure meter of this embodiment, when the blood pressure measurement is automatically started according to the schedule in the nighttime blood pressure measurement mode, the first determination unit and the notification unit are made inoperative by the control unit. Therefore, when the blood pressure measurement is automatically started according to the schedule, the determination of the winding state of the cuff and the notification of the determined winding state of the cuff are not made. This prevents the first determination unit from making useless determinations and the notification unit from attempting useless notifications. Therefore, it can help save power.

[0032] In one embodiment of the blood pressure monitor, the measured site is a wrist.

[0033] Since the blood pressure monitor of one embodiment compresses the wrist, the measured area, it is expected to interfere less with the subject's sleep than blood pressure monitors that compress the upper arm (Imai et al., "Development and evaluation of a home nocturnal blood pressure monitoring system using a wrist-cuff device," Blood Pressure Monitoring 2018, 23, pp. 318-326). Therefore, this blood pressure monitor is suitable for measuring blood pressure at night (while sleeping).

[0034] In one embodiment of the sphygmomanometer, it is characterized in that:

[0035] The blood pressure monitor includes a main body integrally provided with the blood pressure measurement cuff.

[0036] The main body is equipped with a blood pressure measurement unit, the mode operation unit, the first determination unit, and the notification unit. The blood pressure measurement unit temporarily compresses the wrist with the blood pressure measurement cuff, uses a pressure sensor that detects the pressure in the cuff, and measures blood pressure using an oscillometric method.

[0037] Here, the “blood pressure measurement unit” includes, for example, a pump that supplies pressurized fluid to the blood pressure measurement cuff, a valve that discharges fluid from the blood pressure measurement cuff, and a member that drives and controls these pumps and valves.

[0038] The blood pressure monitor of this embodiment can be constructed in an integrated and compact manner, thereby making it easier for the user to handle the device.

[0039] On the other hand, the blood pressure measurement method of the present invention is a blood pressure measurement method for a sphygmomanometer, wherein the sphygmomanometer temporarily compresses a measured portion of a subject using a blood pressure measurement cuff, uses a pressure sensor that detects the pressure within the cuff, and performs blood pressure measurement using an oscillometric method, and is characterized in that:

[0040] The blood pressure monitor includes a mode operation unit for inputting a mode instruction for switching the mode between a normal blood pressure measurement mode for performing blood pressure measurement according to an input blood pressure measurement instruction and a nighttime blood pressure measurement mode for automatically starting blood pressure measurement according to a predetermined schedule.

[0041] The blood pressure measurement method comprises:

[0042] a first determination method, in response to input of the mode instruction, switching to the nighttime blood pressure measurement mode, temporarily pressurizing the cuff to a pressure lower than the cuff pressure used for the blood pressure measurement, and determining the wrapped state of the cuff based on the output of the pressure sensor;

[0043] The second determination method comprises the following steps: in the normal blood pressure measurement mode, before the blood pressure measurement instruction is input and the blood pressure measurement is performed, the cuff is temporarily pressurized to a pressure lower than the cuff pressure used for the blood pressure measurement, and the wrapped state of the cuff is determined based on the output of the pressure sensor according to a normal determination standard that predetermines the degree of the wrapped state of the cuff.

[0044] In the first determination method, in the nighttime blood pressure measurement mode, the wrapped state of the cuff is determined based on a strict determination criterion in which the degree of the wrapped state of the cuff deviates in a tightening direction compared to the normal determination criterion.

[0045] In the blood pressure measurement method,

[0046] When the wrapped state of the cuff is determined, the determined wrapped state of the cuff is notified.

[0047] According to the blood pressure measurement method of the present invention, when the blood pressure of a subject is measured while the subject is sleeping, accurate blood pressure measurement can be performed.

[0048] Furthermore, in yet another aspect, a program of the present invention causes a computer to execute the blood pressure measurement method.

[0049] The blood pressure measurement method can be performed by causing a computer to execute the program of the present invention.

[0050] Effects of the Invention

[0051] As can be seen from the above, the sphygmomanometer and blood pressure measurement method of the present invention can accurately measure blood pressure while the subject is sleeping. In addition, the program of the present invention can cause a computer to execute such a blood pressure measurement method. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is a schematic diagram showing a wrist blood pressure monitor according to an embodiment of the present invention.

[0053] Figure 2 Yes Figure 1 The diagram shows a schematic diagram of a wrist blood pressure monitor wrapped around the left wrist.

[0054] Figure 3 Yes Figure 1 Block diagram of a wrist blood pressure monitor shown.

[0055] Figure 4 It is a graph showing the change in cuff pressure over time.

[0056] Figure 5 Graph showing the relationship between the first time and the second time according to the wrapped state of the cuff.

[0057] Figure 6 is Figure 1 The flowchart shown is a typical blood pressure measurement performed by a wrist blood pressure monitor.

[0058] Figure 7 is Figure 1 Flowchart showing nighttime blood pressure measurement performed with a wrist sphygmomanometer.

[0059] Figure 8 This is a flowchart of nighttime blood pressure measurement performed by a wrist blood pressure monitor according to another embodiment. DETAILED DESCRIPTION

[0060] Hereinafter, embodiments of the wrist blood pressure monitor according to the present invention will be described with reference to the accompanying drawings.

[0061] [Wrist Blood Pressure Monitor]

[0062] Figure 1 The schematic structure of a wrist blood pressure monitor (hereinafter, appropriately referred to as a "blood pressure monitor") 100 according to an embodiment of the present invention is shown. As described later, this blood pressure monitor 100 has a normal mode in which blood pressure measurement begins immediately after the blood pressure measurement switch is turned on, and a nighttime mode in which blood pressure measurement begins at a predetermined scheduled time or at a scheduled time after a specified time.

[0063] [Structure of a wrist blood pressure monitor]

[0064] like Figure 1 As shown, the sphygmomanometer 100 includes a blood pressure measurement cuff 10 that is wrapped around a portion to be measured of a subject, and a sphygmomanometer body 20 that is integrally mounted on the cuff 10 .

[0065] like Figure 2 As shown, the blood pressure monitor 100 of the embodiment is a wrist blood pressure monitor. Therefore, the cuff 10 has a long and narrow band shape to be wrapped around the left wrist 210 of the subject 200, for example. The cuff 10 has an air bag 12 (see FIG. 1 ) for compressing the left wrist 210. Figure 3 ). In addition, in order to always maintain the cuff 10 in an annular shape, a loop (not shown) having appropriate flexibility may be provided in the cuff 10.

[0066] The sphygmomanometer body 20 is integrally attached to a substantially longitudinally central portion of the band-shaped cuff 10. In the embodiment, the portion where the sphygmomanometer body 20 is to be attached corresponds to the palmar side surface 210a of the left wrist 210.

[0067] The sphygmomanometer body 20 has a flat, substantially rectangular parallelepiped shape along the outer circumference of the cuff 10 and is formed small and thin so as not to disturb the sleep of the subject 200. Figure 1 The corners connecting the surface shown in the figure and the side surfaces surrounding it are rounded in a curved shape.

[0068] like Figure 1 As shown, a display unit (notification unit) 30 constituting a display screen and an operation unit 40 for inputting instructions from the subject 200 are provided on the upper surface of the outer surface of the sphygmomanometer body 20 on the side farthest from the left wrist 210 .

[0069] In the embodiment, the display unit 30 includes an LCD (Liquid Crystal Display) that displays predetermined information, such as the maximum blood pressure (in mmHg), the minimum blood pressure (in mmHg), the pulse rate (in beats per minute), and the results of the cuff 10 wrapping determination, described later, in response to control signals from the CPU (Central Processing Unit) 110 (described later). Furthermore, the display unit 30 may be an organic EL (Electro Luminescence) display or an LED (Light Emitting Diode).

[0070] Operation unit 40 includes a plurality of buttons or switches for subject 200 to operate. In the embodiment, operation unit 40 includes a blood pressure measurement start switch 42A, which is used by subject 200 to input a blood pressure measurement instruction in normal mode, and a nighttime measurement switch 42B, which is used by subject 200 to input a blood pressure measurement instruction in nighttime mode. Blood pressure measurement start switch 42A functions as a switch that stops the ongoing blood pressure measurement when pressed during the measurement.

[0071] In the following description, "normal blood pressure measurement" refers to blood pressure measurement initiated immediately after blood pressure measurement start switch 42A is turned on. Furthermore, in the following description, "nighttime blood pressure measurement" refers to blood pressure measurement automatically performed according to a predetermined schedule, for example, while subject 200 is asleep, based on an instruction input via nighttime measurement switch 42B. Blood pressure measurement performed according to a predetermined schedule includes, for example, blood pressure measurement performed at a predetermined time such as 1:00 AM, 2:00 AM, or 3:00 AM, or blood pressure measurement performed, for example, two hours and / or four hours after nighttime measurement switch 42B is pressed.

[0072] In the embodiment, the blood pressure measurement switch 42A and the nighttime measurement switch 42B are both momentary (automatic reset) switches, which are in the on state only while being pressed and return to the off state when released.

[0073] Figure 3 The block structure of the sphygmomanometer 100 is shown.

[0074] The air bladder 12 included in the cuff 10 and various fluid control devices (described below) included in the sphygmomanometer body 20 are connected via air piping 50 so that fluid can flow therethrough.

[0075] In addition to the display unit 30 and operation unit 40 described above, the sphygmomanometer body 20 further includes a CPU 110 as a control unit, a memory 112 as a storage unit, a power supply unit 114, a pressure sensor 62, a pump 72, and a valve 82. Furthermore, the sphygmomanometer body 20 includes an A / D conversion circuit 64 that converts the output of the pressure sensor 62 from an analog signal to a digital signal; a pump drive circuit 74 that drives the pump 72; and a valve drive circuit 84 that drives the valve 82. The pressure sensor 62, pump 72, and valve 82 are connected to the air bladder 12 via the air piping 50 to allow fluid to flow.

[0076] The memory 112 stores programs for controlling the sphygmomanometer 100, data for controlling the sphygmomanometer 100, setting data for setting various functions of the sphygmomanometer 100, and data on blood pressure measurement results. Furthermore, the memory 112 is also used as a working memory for temporarily storing various information during program execution. In particular, the memory 112 in the embodiment serves as a program storage unit, storing a normal blood pressure measurement program and a nighttime blood pressure measurement program for calculating blood pressure using the oscillometric method described later, a normal winding determination program for determining the winding state of the cuff 10 during normal blood pressure measurement, and a nighttime winding determination program for determining the winding state of the cuff 10 during nighttime blood pressure measurement.

[0077] The CPU 110 is configured to control the overall operation of the sphygmomanometer 100. Specifically, the CPU 110 comprises the following components: a pressure control unit that drives the pump 72 or valve 82 according to a program for controlling the sphygmomanometer 100 stored in the memory 112; a first determination unit that determines the wrapped state of the cuff 10 based on the output of the pressure sensor 62 using a nighttime wrapping determination program (described later); a second determination unit that determines the wrapped state of the cuff 10 based on the output of the pressure sensor 62 using a normal wrapping determination program (described later); and a measurement unit that performs blood pressure measurements using a normal blood pressure measurement program or a nighttime blood pressure measurement program (described later). The CPU 110 also displays the blood pressure value and the cuff 10 wrapping determination result obtained through the blood pressure measurement on the display unit 30 and stores them in the memory 112.

[0078] In the embodiment, the power supply unit 114 is comprised of a secondary battery and supplies power to the CPU 110, the pressure sensor 62, the pump 72, the valve 82, the display unit 30, the memory 112, the A / D conversion circuit 64, the pump drive circuit 74, and the valve drive circuit 84. The power supply unit 114 is also configured to switch between an on / off state. When in the off state, if the blood pressure measurement switch 42A is continuously pressed for, for example, three seconds or longer, the power supply unit 114 is switched to the on state.

[0079] The pump 72 supplies air (a fluid) to the air bladder 12 via the air piping 50, thereby increasing the pressure within the air bladder 12 of the cuff 10. The valve 82 is configured to control the cuff pressure by opening to release air from the air bladder 12 via the air piping 50 or by closing to maintain the cuff pressure. The pump drive circuit 74 drives the pump 72 based on a control signal supplied by the CPU 110. The valve drive circuit 84 opens and closes the valve 82 based on a control signal supplied by the CPU 110.

[0080] The pressure sensor 62 and the A / D conversion circuit 64 are configured to detect cuff pressure. In the embodiment, the pressure sensor 62 is a piezo-resistive pressure sensor that detects and outputs the cuff pressure of the air bag 12 as resistance due to the piezo-resistive effect. The A / D conversion circuit 64 converts the output (resistance) of the pressure sensor 62 from an analog signal to a digital signal and outputs it to the CPU 110. In the embodiment, the CPU 110 obtains the cuff pressure based on the resistance output from the pressure sensor 62.

[0081] [Blood Pressure Measurement Procedure]

[0082] The blood pressure measurement program calculates the blood pressure of a subject 200 wearing the blood pressure monitor body 20 on the left wrist 210. The blood pressure measurement program includes a normal blood pressure measurement program and a nighttime blood pressure measurement program. The normal blood pressure measurement program assumes that the subject 200 is sitting on a chair, etc., and maintains the left wrist 210 wearing the blood pressure monitor body 20 at the same height as the heart of the subject 200. The nighttime blood pressure measurement program assumes that the subject 200 is lying on a bed, etc., and places the left wrist 210 wearing the blood pressure monitor body 20 at a position lower than the heart of the subject 200. It is known that the relationship between the height of the blood pressure monitor body 20 and the height of the heart of the subject 200 is different, and thus different blood pressure values ​​are calculated. Therefore, in the normal blood pressure measurement program and the nighttime blood pressure measurement program, the parameters used in the blood pressure calculation are pre-adjusted in consideration of the assumed relationship between the height of the blood pressure monitor body 20 and the height of the heart of the subject 200.

[0083] When executing the normal blood pressure measurement program or the nighttime blood pressure measurement program, CPU 110 obtains a pulse wave signal from the varying components of the pulse wave contained in the cuff pressure obtained by the pressure sensor 62, and uses the various programs stored in the memory 112 to calculate the blood pressure values ​​(maximum blood pressure and minimum blood pressure).

[0084] [Wrapping judgment program]

[0085] In the embodiment, the wrapping determination program determines whether the subject 200 has wrapped the cuff 10 around their left wrist 210 in a "properly wrapped state." As used herein, the properly wrapped state refers to a state in which the circumference of the cylinder formed by the cuff 10 when wrapped around the left wrist 210 is substantially equal to the circumference of the left wrist 210, and appropriate pressure is applied to the left wrist 210. Furthermore, a state in which the cuff 10 is wrapped tighter around the left wrist 210 than in the properly wrapped state, exerting greater pressure on the left wrist 210, is referred to as a "tightly wrapped state." Furthermore, a state in which the cuff 10 is wrapped looser around the left wrist 210 than in the properly wrapped state, exerting less pressure on the left wrist 210, is referred to as a "loosely wrapped state."

[0086] The cuff pressure of the cuff 10 gradually increases over time while the pump 72 supplies air to the air bag 12 of the cuff 10. Figure 4 As shown, the relationship between time and cuff pressure varies depending on the wrapped state of the cuff 10 .

[0087] exist Figure 4, solid lines 310 and 320 represent the relationship between time and cuff pressure in a properly wound state. Dashed lines 312 and 322 represent the relationship between time and cuff pressure in a tightly wound state. Dashed lines 314 and 324 represent the relationship between time and cuff pressure in a loosely wound state. Of the two solid lines 310 and 320, the solid line 310 on the left side of the figure represents the relationship between time and cuff pressure when a small-sized cuff is used, and the solid line 320 on the right side of the figure represents the relationship between time and cuff pressure when a large-sized cuff is used. Similarly, of the two dashed lines 312 and 322, the dashed line 312 on the left side of the figure represents the relationship between time and cuff pressure when a small-sized cuff is used, and the dashed line 322 on the right side of the figure represents the relationship between time and cuff pressure when a large-sized cuff is used. In addition, the dotted line 314 on the left side of the two dotted lines represents the relationship between time and cuff pressure when a small cuff is used, while the dashed line 324 on the right side of the figure represents the relationship between time and cuff pressure when a large cuff is used. The illustrated relationship between time and cuff pressure indicates that the closer the cuff 10 is to a tightened state, the more rapidly the cuff pressure increases. Furthermore, the relationship between time and cuff pressure varies depending on the size of the cuff 10; smaller cuffs 10 are more likely to experience a rapid increase in cuff pressure.

[0088] like Figure 4 As shown, in the aforementioned relationship between time and cuff pressure, the difference in the increasing tendency of the cuff pressure, which varies depending on the wrapped state of the cuff 10, occurs at an earlier stage, i.e., at a lower pressure. Therefore, the time required for the cuff pressure to rise from a first pressure P1 to a second pressure P2 (P1 < P2), i.e., first time 336, reflects the wrapped state of the cuff 10. For example, the closer the cuff 10 is to a tightly wrapped state, the shorter the first time 336, while the closer the cuff 10 is to a loosely wrapped state, the longer the first time 336.

[0089] In addition, the tendency of the cuff pressure to increase with time varies depending on the size of the cuff 10. Even in the same wrapped state, the first time 336 varies depending on the size of the cuff 10. Figure 4 As shown, the influence of cuff 10 size occurs during the high cuff pressure phase. Therefore, the second time 346, when the cuff pressure rises from a third pressure P3 greater than first pressure P1 and second pressure P2 to a fourth pressure P4 (P3 < P4), reflects the size of cuff 10. For example, the smaller the size of cuff 10, the shorter the second time 346, and the larger the size of cuff 10, the longer the second time 346.

[0090] Pressures P1, P2, P3, and P4 are set to, for example, 10 mmHg, 15 mmHg, 25 mmHg, and 35 mmHg, respectively. However, these pressures are not limited thereto and may be determined based on actual measured values ​​within a range lower than the cuff pressure used for blood pressure measurement (the lowest blood pressure measured (diastolic blood pressure)).

[0091] Figure 5 The figure shows the relationship between first time 336 for the cuff pressure to change from a first pressure P1 to a second pressure P2 and second time 346 for the cuff pressure to change from a third pressure P3 to a fourth pressure P4. Circles indicate the relationship between first time 336 and second time 346, respectively, measured in the properly wound state. Triangles indicate the relationship between first time 336 and second time 346, respectively, measured in the loosely wound state. Although not shown, when characteristic curves are plotted based on the data indicated by the circles and the data indicated by the triangles, the characteristic curve in the properly wound state indicated by the circles shows a flatter gradient than the characteristic curve in the loosely wound state. Furthermore, in both the properly wound state and the loosely wound state, the second time 346 increases relative to the first time 336. Therefore, in both the properly wound state and the loosely wound state, the relationship between first time 336 and second time 346 is substantially linear.

[0092] As described above, in the embodiment, for normal blood pressure measurement (blood pressure measurement performed with the subject 200 sitting on a chair), the Figure 5 The relationship between first time 336 and second time 346 is shown, and a normal properly wound threshold value 350, represented by a linear function shown as a solid line, is set as a normal criterion (normal criterion) for determining the wound state of cuff 10. Furthermore, when blood pressure measurement start switch 42A is turned on while cuff 10 is wound around left wrist 210 of subject 200, air is supplied to cuff 10, and first time 336 and second time 346 are measured based on the change in cuff pressure at that time. The relationship between first time 336 and second time 346 is compared with normal properly wound threshold value 350 to determine whether cuff 10 is properly wound (or loosely wound).

[0093] On the other hand, as described above, since the blood pressure measurement at night (the blood pressure measurement performed with the subject 200 lying down) is performed multiple times according to a predetermined schedule, the cuff 10 tends to become loose. Therefore, in the blood pressure measurement at night, the cuff 10 is preferably more appropriately wound so that it is not easily loosened. Therefore, for the blood pressure measurement at night, the appropriate winding state at night (the second reference value) 360 is set to be lower than the normal appropriate winding threshold 350 so that the winding state of the cuff 10 in the blood pressure measurement at night becomes a strict judgment standard (strict judgment standard), wherein the strict judgment standard means that the degree of the winding state of the cuff 10 is shifted in the direction of tightening compared to the judgment standard (normal judgment standard) in the normal blood pressure measurement. Furthermore, when the cuff 10 is wrapped around the left wrist 210 of the subject 200 and the nighttime measurement switch 42B is turned on, air is supplied to the cuff before the subject goes to bed, and the first time 336 and the second time 346 are measured based on the change in the cuff pressure at this time. The relationship between the first time and the second time is compared with the nighttime appropriate wrapping threshold to determine whether the cuff is in an appropriately wrapped state (or whether it is in a loosely wrapped state).

[0094] In the embodiment, the temporary function of the normal appropriate winding threshold 350 and the temporary function of the nighttime appropriate winding threshold 360 are set as, for example, the following Mathematical Formula 1 and Mathematical Formula 2. However, these functions are merely examples, and may be defined by other functions.

[0095] [Mathematical formula 1]

[0096] (First time) = 0.55 × (Second time) + 0.08

[0097] [Mathematical formula 2]

[0098] (First time) = 0.55 × (Second time) - 0.05

[0099] When the CPU 110 executes the normal winding determination program or the nighttime winding determination program, the CPU 110 calculates the first time 336 and the second time 346 based on the cuff pressure obtained by the pressure sensor 62, and calculates the time interval ( Figure 5 Whether the cuff is in a loosely wound state or a properly wound state is determined by determining whether the point (shown above) is above (loosely wound region) or below (properly wound region) the corresponding normal proper winding threshold value (temporary function) 350 or nighttime proper winding threshold value (temporary function) 360. The determination result is displayed on the display unit 30, for example.

[0100] [Normal blood pressure measurement mode]

[0101] Normal blood pressure measurement will be described. In this case, when the blood pressure measurement switch 42A of the blood pressure monitor body 20 is pressed once while the cuff 10 of the blood pressure monitor 100 is wrapped around the left wrist 210 of the subject 200, a normal blood pressure measurement instruction (mode instruction) is output to the CPU 110. CPU 110 then drives the pump 72 and valve 82 to increase the cuff pressure of the cuff 10, thereby compressing the left wrist 210. In this state, the normal winding determination routine described above is executed. If the cuff 10 is loosely wound, the display unit 30 displays the message "Please rewind"; if the cuff 10 is properly wound, the display unit 30 displays the message "Properly wound." Furthermore, a normal blood pressure measurement routine using the oscillometric method is executed. During blood pressure measurement (for example, while the cuff 10 is being pressurized), if the blood pressure measurement switch 42A is pressed again, the pump 72 stops, the valve 82 opens, and the blood pressure measurement ends.

[0102] Figure 6 The flowchart shows the operation flow when the subject 200 performs normal blood pressure measurement using the sphygmomanometer 100. During this normal blood pressure measurement, the subject 200 wearing the sphygmomanometer 100 on the left wrist 210 remains seated on a chair or the like.

[0103] In this state, if Figure 6 As shown in step S1, when subject 200 presses blood pressure measurement switch 42A provided on sphygmomanometer body 20 to input a normal blood pressure measurement instruction, CPU 110 initializes pressure sensor 62 (step S2). Specifically, CPU 110 initializes the processing memory area and, while pump 72 is stopped and valve 82 is open, adjusts pressure sensor 62 to 0 mmHg (setting atmospheric pressure to 0 mmHg).

[0104] Next, CPU 110 closes valve 82 via valve drive circuit 84 (step S3), and then drives pump 72 via pump drive circuit 74 to begin pressurizing cuff 10 (air bag 12) (step S4). At this time, CPU 110 controls the pressurization rate of the cuff pressure (the pressure within air bag 12) based on the output of pressure sensor 62 while supplying air from pump 72 to air bag 12 via air piping 50.

[0105] If the cuff pressure output by pressure sensor 62 does not reach the predetermined pressure (if the answer is "No" in step S5), step S4 is repeated. In this case, CPU 110 obtains, based on the change in the cuff pressure output by pressure sensor 62, a first time 336, which is the time when the cuff pressure changes from the first pressure P1 to the second pressure P2, and a second time 346, which is the time when the cuff pressure changes from the third pressure P3 to the fourth pressure P4.

[0106] When the cuff pressure output by pressure sensor 62 reaches a predetermined pressure (when the "Yes" branch is taken in step S5), CPU 110 uses the normal winding determination program stored in memory 112 to determine the winding state of cuff 10 based on the acquired first time 336 and second time 346. If cuff 10 is loosely wound, CPU 110 displays a message "Please rewind" on display 30, or if cuff 10 is properly wound, CPU 110 displays a message "Properly wound" on display 30 (step S6). Thus, by only performing blood pressure measurement when cuff 10 is properly wound, the reliability of the measurement results obtained in the normal blood pressure measurement mode is increased.

[0107] Next, in step S7 , the CPU 110 calculates the blood pressure values ​​(maximum blood pressure and minimum blood pressure) based on the pulse wave signal obtained at that time using the above-described normal blood pressure measurement program stored in the memory 112 .

[0108] At this moment, if CPU 110 is unable to calculate the blood pressure value due to insufficient data (when branching to "No" in step S8), the processing of steps S4 to S8 is repeated as long as the cuff pressure does not reach the upper limit pressure (for example, pre-set to 300 mmHg for safety reasons).

[0109] When the blood pressure value is calculated (when the control branch is "YES" in step S8), CPU 110 controls to stop pump 72 (step S9), open valve 82 (step S10), and exhaust the air in cuff 10 (air bag 12).

[0110] Then, the CPU 110 controls the display unit 30 to display the calculated blood pressure value (step S11 ) and stores the blood pressure value in the memory 112 .

[0111] [Nighttime blood pressure measurement mode]

[0112] Nighttime blood pressure measurement will be described. When the cuff 10 of the sphygmomanometer 100 is wrapped around the left wrist 210 of the subject 200, and the subject 200, who is not asleep, presses the nighttime measurement switch 42B of the sphygmomanometer body 20 once, a nighttime blood pressure measurement indication (mode indication) is output to the CPU 110. Consequently, the CPU 110 drives the pump 72 and valve 82 to increase the cuff pressure of the cuff 10, temporarily compressing the left wrist 210 with the cuff 10. In this state, the aforementioned nighttime winding determination program is executed. If the cuff 10 is in a loosely wound state, a message such as "Please rewind" is displayed on the display unit 30. Alternatively, if the cuff 10 is in a properly wound state, a message such as "Properly wound" is displayed on the display unit 30.

[0113] The nighttime blood pressure measurement sequence is then executed according to a predetermined schedule. However, if the nighttime measurement switch 42B is pressed again during the period leading up to the blood pressure monitor 100 performing a blood pressure measurement of the subject while they are asleep (e.g., during the standby period leading up to the execution of the predetermined nighttime blood pressure measurement sequence), the nighttime blood pressure measurement is stopped, and the nighttime blood pressure measurement sequence is not executed.

[0114] In the embodiment, the nighttime blood pressure measurement schedule is configured to execute the nighttime blood pressure measurement program at a predetermined time (e.g., four hours) after the nighttime measurement switch 42B is pressed. Furthermore, if necessary, the nighttime blood pressure measurement program is executed at predetermined time intervals (e.g., two hours) from that time until a predetermined time (e.g., 7:00 AM). In an embodiment in which the time to perform the nighttime blood pressure measurement is calculated based on the time when the nighttime measurement switch 42B is pressed, the nighttime blood pressure measurement program includes a measurement time determination program (not shown), and the measurement time is determined based on this time determination program.

[0115] The execution schedule of nighttime blood pressure measurement is not limited to this, and may also be set to predetermined scheduled times, such as executing the nighttime blood pressure measurement program at 1:00, 2:00, or 3:00 in the morning.

[0116] Figure 7 The flowchart shows the operation flow when the subject 200 performs nighttime blood pressure measurement using the sphygmomanometer 100. During the nighttime blood pressure measurement, the subject 200, wearing the sphygmomanometer 100 on the left wrist 210, remains lying in bed.

[0117] In this state, if Figure 7 As shown in step S101, when the subject 200 presses the nighttime measurement switch 42B provided on the sphygmomanometer body 20 and inputs a nighttime blood pressure measurement instruction, the CPU 110 switches the program for determining the winding state of the cuff 10 from the normal winding determination program to the nighttime winding determination program (step S102).

[0118] Next, CPU 110 initializes pressure sensor 62 (step S103 ). Specifically, CPU 110 initializes the processing memory area and adjusts pressure sensor 62 to 0 mmHg (setting atmospheric pressure to 0 mmHg) with pump 72 stopped and valve 82 open.

[0119] Next, the CPU 110 closes the valve 82 via the valve drive circuit 84 (step S104 ), and then drives the pump 72 via the pump drive circuit 74 to start pressurizing the cuff 10 (air bladder 12 ) (step S105 ).

[0120] When the cuff pressure output by the pressure sensor 62 does not reach the specified pressure (when branching to "No" in step S106), CPU110 repeatedly performs step S105, and obtains the first time 336 when the cuff pressure changes from the first pressure P1 to the second pressure P2 and the second time 346 when the cuff pressure changes from the third pressure P3 to the fourth pressure P4 based on the change of the cuff pressure output by the pressure sensor 62.

[0121] When the cuff pressure output by pressure sensor 62 reaches a predetermined pressure (fourth pressure P4) (when the "Yes" branch is taken in step S106), CPU 110 uses the aforementioned nighttime winding determination program stored in memory 112 to determine the winding state of cuff 10 based on the acquired first time 336 and second time 346. If the cuff 10 is loosely wound, CPU 110 displays a message "Please rewind" on display 30, or if the cuff 10 is properly wound, CPU 110 displays a message "Appropriately wound" on display 30 (step S107). In this nighttime winding determination program, the appropriate winding state of cuff 10 is determined based on the aforementioned strict determination criteria. Therefore, the subject can adjust the winding state of cuff 10 to a level that is determined to be "appropriately wound" based on the aforementioned strict determination criteria. Therefore, when the sphygmomanometer 100 automatically starts blood pressure measurement according to the schedule in the nighttime blood pressure measurement mode, it can be expected that the cuff wrapping state is maintained "appropriately" based on the normal judgment criteria. Therefore, the sphygmomanometer 100 can perform accurate blood pressure measurement in the nighttime blood pressure measurement mode.

[0122] After displaying the above-mentioned text, the CPU 110 controls the pump 72 to stop (step S108 ), opens the valve 82 (step S109 ), and exhausts the air in the cuff 10 (air bag 12 ).

[0123] Next, CPU 110 determines whether it is the measurement time specified in the specified schedule (step S110 ). If it is not the measurement time specified in the schedule (when the decision is “No” in step S110 ), CPU 110 waits until the measurement time becomes the measurement time.

[0124] When the measurement time is reached (when the decision is made to "Yes" in step S110), Figure 6 Similarly to step S2 , CPU 110 initializes pressure sensor 62 (step S111 ).

[0125] Next, with Figure 6Similarly to steps S3 and S4, CPU 110 closes valve 82 via valve drive circuit 84 (step S112), then drives pump 72 via pump drive circuit 74 to begin pressurizing cuff 10 (air bag 12) (step S113). At this time, CPU 110 controls the pressurization rate of the cuff pressure (the pressure within air bag 12) based on the output of pressure sensor 62 while supplying air from pump 72 to air bag 12 via air piping 50.

[0126] Next, in step S114, Figure 6 Similarly, in step S7 , CPU 110 calculates blood pressure values ​​(maximum blood pressure and minimum blood pressure) based on the pulse wave signal acquired at that time using the aforementioned nighttime blood pressure measurement program stored in memory 112 .

[0127] At this moment, if CPU 110 is unable to calculate the blood pressure value due to insufficient data (when branching to "No" in step S115), steps S113 and S114 are repeated as long as the cuff pressure does not reach the upper limit pressure (for safety reasons, pre-set to 300 mmHg, for example).

[0128] When the blood pressure value is calculated (when the control branch goes to “YES” in step S115 ), CPU 110 controls to stop pump 72 (step S116 ), open valve 82 (step S117 ), and exhaust the air in cuff 10 (air bag 12 ).

[0129] Then, the CPU 110 controls the display unit 30 to display the calculated blood pressure value (step S118 ) and stores the blood pressure value in the memory 112 .

[0130] When a blood pressure measurement specified in the schedule is completed, CPU 110 determines whether all blood pressure measurements specified in the schedule have been completed (step S119). If a blood pressure measurement specified in the schedule is still scheduled (if the "Not Completed" branch is taken in step S119), CPU 110 returns to step S110 to determine whether it is the next measurement time specified in the schedule. If it is not the next measurement time (if the "No" branch is taken in step S110), CPU 110 waits until the next measurement time becomes the next measurement time.

[0131] When the next measurement time specified in the above schedule comes (when the "Yes" branch is taken in step S110), CPU 110 repeatedly performs the processing of steps S111 to S118. In step S119, it is again determined whether all blood pressure measurements specified in the above schedule have been completed. Here, while CPU 110 is repeatedly performing the processing of steps S111 to S118, in order to avoid unnecessary winding determinations, the night winding determination program of steps S103 to S109 is not executed. Therefore, when the blood pressure measurement is automatically started by processing steps S111 to S118 for the second or subsequent time according to the above schedule, the winding state of the cuff 10 is not determined, and the determined winding state is not notified. This prevents the CPU 110 from making unnecessary determinations and attempting unnecessary notifications. Therefore, it can help save power.

[0132] When all the blood pressure measurements specified in the above-mentioned schedule are completed (when the process branches to "END" in step S119), CPU 110 ends the nighttime blood pressure measurement.

[0133] During the normal and nighttime blood pressure measurements described above, if the cuff 10 is loosely wound, a message "Please rewind" is displayed, or if the cuff 10 is properly wound, a message "Properly wound" is displayed (steps S6 and S107). This allows the subject 200 to understand the wound state of the cuff 10 before actually performing the blood pressure measurement. When the message "Please rewind" is displayed, the subject 200 can stop the blood pressure measurement and rewind the cuff 10. Therefore, since the cuff 10 can be easily wrapped around the left wrist 210 of the subject 200 in a properly wound state, the subject's blood pressure can be accurately measured even while the subject 200 is sleeping.

[0134] Furthermore, the nighttime winding determination program executed during nighttime blood pressure measurement determines the wound state of cuff 10 using a lower threshold, i.e., stricter conditions, than the normal winding determination program, thereby urging subject 200 to wind cuff 10 more appropriately or slightly more tightly. Consequently, during nighttime blood pressure measurement, even if the cuff is repeatedly pressurized and depressurized, the winding of cuff 10 does not loosen, enabling accurate blood pressure measurement.

[0135] Thus, according to the sphygmomanometer 100, in the nighttime blood pressure measurement mode, the oscillometric blood pressure measurement is performed with the cuff properly wrapped. Therefore, according to the sphygmomanometer, accurate blood pressure measurement can be performed while the subject is sleeping.

[0136] Blood pressure monitor 100 compresses the wrist (left wrist 210 in this embodiment, but may also be the right wrist) as the measured site. Therefore, compared to blood pressure monitors that compress the upper arm, it is expected that it is less likely to disturb the sleep of subject 200 (Imai et al., "Development and evaluation of a home nocturnal blood pressure monitoring system using a wrist-cuff device," Blood Pressure Monitoring 2018, 23, pp. 318-326). Therefore, blood pressure monitor 100 is suitable for nighttime blood pressure measurement.

[0137] Furthermore, the sphygmomanometer 100 is integrally and compactly configured as a wrist sphygmomanometer, and thus is easy for the subject 200 to handle.

[0138] [Other embodiments]

[0139] In the above embodiment, the CPU 110 switches from the normal winding determination program to the nighttime winding determination program in step S102 during nighttime blood pressure measurement in order to determine the winding state of the cuff 10 under strict conditions. Figure 8 As shown, the normal winding determination program may be executed even during nighttime blood pressure measurement without switching.

[0140] In the above-described embodiment, the CPU 110 calculates the blood pressure while the cuff 10 (air bladder 12) is being inflated. However, the CPU 110 may calculate the blood pressure while the cuff is being deflated.

[0141] In the above-mentioned embodiment, the blood pressure monitor 100 has: a display unit 30, which displays text such as "Please rewind" if the cuff 10 is in a loosely wound state, or displays text such as "Properly wound" if the cuff 10 is in a properly wound state; but the blood pressure monitor 100 can also notify the subject of the winding determination result through a voice notification unit, which notifies by reading the content of the text using voice.

[0142] In the above embodiment, the blood pressure monitor 100 has a blood pressure measurement switch 42A for inputting a normal blood pressure measurement instruction and a nighttime measurement switch 42B for inputting a nighttime blood pressure measurement instruction. However, for example, the signal receiving unit of the blood pressure monitor may also receive an instruction (mode instruction) from a smartphone or the like existing outside the blood pressure monitor via wireless communication, and use the signal received by the signal receiving unit instead of the signal output from the normal blood pressure measurement switch or the nighttime measurement switch to the CPU.

[0143] In the above embodiment, although the blood pressure monitor 100 is configured so that the blood pressure measurement switch 42A outputs a signal indicating normal blood pressure measurement to the CPU 110, and the nighttime measurement switch 42B outputs a signal indicating the nighttime blood pressure amount to the CPU 110, it may also be configured so that, for example, the signal indicating normal blood pressure measurement (mode indication) is output to the CPU by pressing the blood pressure measurement switch once, and the signal indicating nighttime blood pressure measurement (mode indication) is output to the CPU by pressing the blood pressure measurement switch twice within a certain period of time.

[0144] In the above embodiment, the sphygmomanometer body 20 is provided integrally with the cuff 10 , but may be provided separately from the cuff and connected to the cuff 10 (air bladder 12 ) via a flexible air tube so that fluid can flow.

[0145] In the above embodiment, the normal blood pressure measurement program, the nighttime blood pressure measurement program, the normal winding determination program, the nighttime winding determination program, and these processes are stored as software in memory 112. However, these programs and processes may also be stored on non-transitory media such as CDs (Compact Discs), DVDs (Digital Versatile Discs), or flash memory. By installing the software stored on these media into a physical computer device such as a personal computer, PDA (Personal Digital Assistant), or smartphone, these computer devices can execute the programs and processes described above.

[0146] Description of reference numerals:

[0147] 100: Blood pressure monitor, 10: Cuff, 30: Notification unit (display unit), 40: Mode operation unit, 62: Pressure sensor, 110: First determination unit (CPU), 210: Wrist.

Claims

1. A blood pressure monitor that measures blood pressure using an oscillometric method by temporarily compressing a measured area with a blood pressure measurement cuff and using a pressure sensor that detects the pressure within the cuff, wherein: The blood pressure monitor has: a mode operation unit for inputting a mode instruction for switching the mode between a normal blood pressure measurement mode in which blood pressure measurement is performed according to an input blood pressure measurement instruction and a nighttime blood pressure measurement mode in which blood pressure measurement is automatically started according to a predetermined schedule; a first determination unit that switches to the nighttime blood pressure measurement mode in response to input of the mode instruction, temporarily pressurizes the cuff to a pressure lower than the cuff pressure used for the blood pressure measurement before starting to wait for a measurement time based on the schedule, and determines a wrapped state of the cuff based on an output of the pressure sensor; as well as The second determination unit temporarily pressurizes the cuff to a pressure lower than the cuff pressure used for the blood pressure measurement in the normal blood pressure measurement mode before the blood pressure measurement instruction is input and the second determination unit determines the wrapped state of the cuff based on the output of the pressure sensor according to a normal determination criterion that predetermines the degree of the wrapped state of the cuff. The first determination unit measures a first passage time required for the pressure of the blood pressure measurement cuff to pass through a predetermined first pressure range lower than the cuff pressure used for the blood pressure measurement. The first determination unit measures a second passage time required for the pressure of the blood pressure measurement cuff to pass through a predetermined second pressure range that is higher than the first pressure range and lower than the cuff pressure used for the blood pressure measurement, wherein a starting pressure value of the second pressure range is higher than an ending pressure value of the first pressure range. In the nighttime blood pressure measurement mode, the wrapped state of the cuff is determined based on the measured first and second passing times according to a strict determination criterion set on a plane having the second passing time as the horizontal axis and the first passing time as the vertical axis, wherein the degree of the wrapped state of the cuff is shifted toward a tightening direction and is lower than the normal determination criterion. The blood pressure monitor includes a notification unit configured to notify the determined wrapped state of the cuff before starting to wait for a measurement time based on the schedule, following determination of the wrapped state of the cuff.

2. The blood pressure monitor according to claim 1, wherein The first determination unit determines whether the wrapped state of the cuff is appropriate based on the determined wrapped state of the cuff according to the strict determination criterion. The second determination unit determines whether the wrapped state of the cuff is appropriate based on the determined wrapped state of the cuff according to the normal determination criterion. The notification unit notifies whether the wrapped state of the cuff is appropriate.

3. The sphygmomanometer according to claim 1 or 2, wherein: This blood pressure monitor includes a control unit that, when blood pressure measurement is automatically started according to the schedule in the nighttime blood pressure measurement mode, disables the first determination unit and the notification unit.

4. The sphygmomanometer according to claim 1 or 2, wherein: The measured part is the wrist.

5. The sphygmomanometer according to claim 4, wherein The blood pressure monitor includes a main body integrally provided with the blood pressure measurement cuff. The main body is equipped with a blood pressure measurement unit, the mode operation unit, the first determination unit and the notification unit. The blood pressure measurement unit temporarily compresses the wrist with the blood pressure measurement cuff, uses a pressure sensor that detects the pressure in the cuff, and measures blood pressure using an oscillometric method.

6. A blood pressure measurement method for a sphygmomanometer, wherein the sphygmomanometer temporarily compresses a measured portion of a subject using a blood pressure measurement cuff, uses a pressure sensor that detects the pressure within the cuff, and performs blood pressure measurement using an oscillometric method, wherein: The blood pressure monitor includes a mode operating unit for inputting a mode instruction for switching the mode between a normal blood pressure measurement mode for performing blood pressure measurement according to an input blood pressure measurement instruction and a nighttime blood pressure measurement mode for automatically starting blood pressure measurement according to a predetermined schedule. The blood pressure measurement method comprises: A first determination method comprises: switching to the nighttime blood pressure measurement mode upon input of the mode instruction, temporarily pressurizing the cuff to a pressure lower than the cuff pressure used for the blood pressure measurement before starting to wait for the measurement time based on the schedule, and determining the wrapped state of the cuff based on the output of the pressure sensor; The second determination method comprises the following steps: in the normal blood pressure measurement mode, before the blood pressure measurement instruction is input and the blood pressure measurement is performed, the cuff is temporarily pressurized to a pressure lower than the cuff pressure used for the blood pressure measurement, and the wrapped state of the cuff is determined based on the output of the pressure sensor according to a normal determination standard that predetermines the degree of the wrapped state of the cuff. In the first determination method, measuring a first passage time required for the pressure of the blood pressure measurement cuff to pass through a predetermined first pressure range lower than the cuff pressure used for the blood pressure measurement; measuring a second passage time required for the pressure of the blood pressure measurement cuff to pass through a predetermined second pressure range that is higher than the first pressure range and lower than the cuff pressure used for the blood pressure measurement, wherein a starting pressure value of the second pressure range is higher than an ending pressure value of the first pressure range; In the nighttime blood pressure measurement mode, the wrapped state of the cuff is determined based on the measured first and second passing times according to a strict determination criterion set on a plane having the second passing time as the horizontal axis and the first passing time as the vertical axis, wherein the degree of the wrapped state of the cuff is shifted toward a tightening direction and is lower than the normal determination criterion. In the blood pressure measurement method, As the wrapped state of the cuff is determined, the determined wrapped state of the cuff is notified before starting to wait for the measurement time based on the schedule. 7 . A recording medium having a program recorded thereon, the program causing a computer to execute the blood pressure measurement method according to claim 6 .

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