JP2008099819A - Electronic hemomanometer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent omitted detection of pulse waves immediately after the beginning of decompression and prolonged measurement by starting the decompression of a cuff pressure at a target decompression rate in an electronic hemomanometer. <P>SOLUTION: When the pressure within a pressure cuff bag 1 is reduced by a decompression means 4, the pressure within the pressure cuff bag 1 is detected by a pressure detection means 2. A control initial value adjustment means 14 adjusts the control initial value for the start of the decompression in the subsequent measurement of blood pressure from the pressure within the pressure cuff bag 1 detected. In the start of reducing the pressure of the pressure cuff bag 1 for the subsequent measurement of blood pressure, the degree of the opening of an exhaust valve of the decompression means 4 is controlled from the control initial value adjusted in the decompression for the current measurement of blood pressure. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electronic sphygmomanometer, and more particularly to an electronic sphygmomanometer that measures blood pressure while the cuff pressure is reduced.

  Some electronic sphygmomanometers measure blood pressure while gradually decreasing the cuff pressure (hereinafter referred to as cuff pressure). In this type of electronic blood pressure monitor, when the air in the cuff is discharged, the cuff pressure reduction speed becomes a desired speed by controlling the opening degree of the exhaust valve composed of an electromagnetic valve connected to the cuff. It is configured as follows. In general, the closing force of an electromagnetic valve is determined by a control value for controlling the opening degree of the electromagnetic valve and a power supply voltage. Conventionally, the initial value of the control value (hereinafter referred to as the control initial value) is a state in which a user with an average physique has wound the cuff around the upper arm, etc., with just the right and left, and pressurized to a predetermined cuff pressure with the rated voltage. It is fixed at a value that is optimal when.

  There is also known a control device for a constant speed exhaust device that measures the pressure in a pressurizing space such as an arm band and displaces a piezoelectric element actuating member for opening and closing a valve based on the measurement signal. The sphygmomanometer using this control device pumps air to the armband, and when the pressure in the armband reaches a set value, the piezoelectric element actuating member is displaced to form a gap between the valve and the exhaust port. Thus, the air on the armband side is exhausted at a preset speed. Further, the pressure in the armband is measured, and the opening degree of the valve is adjusted so that the exhaust speed becomes a set value by feedback control (see, for example, Patent Document 1).

JP-A-2-2121121 (page 4, lower left column, 8th line to 17th line)

  However, in the above-described conventional electronic blood pressure monitor, since the initial control value of the electromagnetic valve is a fixed value, for example, when the user's physique deviates significantly from the average, due to changes over time of the electromagnetic valve, individual differences of the electromagnetic valve, The cuff decompression may be started at a speed higher or lower than the target decompression speed. When the cuff decompression is started at a higher speed than the target decompression speed, there is a problem that the pulse wave may not be detected immediately after the decompression is started. On the other hand, if the pressure reduction is started at a speed lower than the target pressure reduction speed, there is a problem that the time required until the blood pressure measurement is completed becomes long. These problems also apply to the sphygmomanometer using the control device disclosed in Patent Document 1.

  The present invention updates the initial control values of electromagnetic valves and the like based on the pressure reduction rate at the previous blood pressure measurement and starts cuff pressure reduction at the target pressure reduction rate in order to eliminate the above-described problems caused by the prior art. Accordingly, an object of the present invention is to provide an electronic sphygmomanometer that can prevent a pulse wave detection omission immediately after the start of decompression and a long measurement time.

  In order to solve the above-described problems and achieve the object, an electronic sphygmomanometer according to the invention of claim 1 controls a cuff, a decompression means for decompressing the pressure in the cuff, and the decompression means based on a control value. Based on the pressure in the cuff detected by the pressure detecting means when the pressure in the cuff is reduced by the pressure reducing means, the pressure detecting means for detecting the pressure in the cuff, Control value adjusting means for correcting the control value for the next decompression.

  According to a second aspect of the present invention, in the electronic sphygmomanometer according to the first aspect of the invention, the control value is a control initial value for the decompression control means to control the decompression means at the start of decompression. It is characterized by.

  According to a third aspect of the present invention, in the electronic sphygmomanometer according to the second aspect of the present invention, the control value adjusting means determines whether the elapsed time from the start of decompression coincides with the set value. A decompression speed calculating means for calculating a decompression speed at a time point when the predetermined time has elapsed from the start of decompression by the elapsed time judging means, and a decompression speed calculated by the decompression speed calculating means from a target decompression speed. Decompression speed deviation calculating means for calculating a deviation, and pressure drop amount calculating for calculating a decrease amount of the pressure in the cuff from the start of depressurization when it is determined by the elapsed time determining means that a predetermined time has elapsed from the start of the depressurization. And a correction amount of the control initial value is determined based on the speed deviation calculated by the pressure reducing speed deviation calculating means and the pressure drop calculated by the pressure drop calculating means. The control initial value correction amount determining means, the control initial value correcting means for correcting the control initial value based on the correction amount determined by the control initial value correction amount determining means, and the control initial value correcting means. Control initial value storage means for storing the control initial value.

  According to a fourth aspect of the present invention, in the electronic sphygmomanometer according to the third aspect of the present invention, the deviation of the decompression speed from the target decompression speed, the pressure drop amount from the start of decompression, the target decompression speed, and the control initial value are corrected. A control initial value correction amount table that defines a relationship between the amounts, wherein the control initial value correction amount determination means further determines a correction amount of the control initial value based on the control initial value correction amount table. Features.

  The electronic sphygmomanometer according to the invention of claim 5 is the electronic blood pressure monitor according to claim 2, wherein the control value adjusting means includes a decompression speed calculating means for calculating a decompression speed during decompression, and the decompression speed calculating means. Decompression speed deviation calculating means for calculating a deviation of the calculated decompression speed from the target decompression speed, target decompression speed arrival judging means for judging that the decompression speed has reached the target decompression speed, and said target decompression speed arrival judging means The elapsed time calculation means for calculating the elapsed time from the start of pressure reduction until it is determined that the target pressure reduction speed is reached, and the cuff until the target pressure reduction speed arrival determination means determines that the target pressure reduction speed is reached. A pressure drop amount calculating means for calculating a pressure drop amount from the start of pressure reduction, an elapsed time calculated by the elapsed time calculating means, and a pressure drop amount calculating means. A control initial value correction amount determining means for determining a correction amount of the control initial value based on the pressure drop amount, and the control initial value based on the correction amount determined by the control initial value correction amount determining means. Control initial value correcting means for correcting; and control initial value storing means for storing the control initial value corrected by the control initial value correcting means.

  According to a sixth aspect of the present invention, in the electronic sphygmomanometer according to the fifth aspect of the present invention, the control initial value correction amount determining means includes the pressure drop amount from the start of pressure reduction, the elapsed time from the start of pressure reduction, and the control initial value. The correction amount of the initial control value is determined based on the relational expression of the value correction amount.

  According to the present invention, the control value adjusting means controls the decompression means during decompression based on the pressure in the cuff detected by the pressure detection means when the pressure in the cuff is decompressed by the decompression means. The control value is corrected. At the next decompression, the decompression means is controlled by the decompression control means based on the control value adjusted at the current decompression.

  According to the electronic sphygmomanometer according to the present invention, since the current decompression control is performed based on the control initial value corrected and adjusted at the previous decompression, the cuff can be decompressed at a decompression speed close to the target value. Therefore, there is an effect that it is possible to prevent a pulse wave detection omission immediately after the start of decompression and a long measurement time.

  Exemplary embodiments of an electronic blood pressure monitor according to the present invention will be described below in detail with reference to the accompanying drawings. Note that, in the following description of the embodiments and the accompanying drawings, the same reference numerals are given to the same components, and duplicate descriptions are omitted.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing the overall configuration of the electronic blood pressure monitor according to Embodiment 1 of the present invention. As shown in FIG. 1, the electronic sphygmomanometer includes a cuff 1, a pressure detection unit 2, a pressurization unit 3, a decompression unit 4, a display unit 5, an operation unit 6, and a microcomputer (hereinafter referred to as a microcomputer) 7. Yes. The cuff 1, the pressure detection means 2, the pressurization means 3 and the decompression means 4 are connected by a tube 8.

  The pressure detection means 2 detects the pressure in the cuff 1. The pressure detection means 2 is comprised by the pressure sensor, for example. The pressurizing means 3 pressurizes the cuff 1 based on the output signal of the microcomputer 7. The pressurizing means 3 is constituted by, for example, a pump that sends a fluid such as air (hereinafter simply referred to as air or the like) to the cuff 1.

  The decompression means 4 reduces the pressure in the cuff 1 based on the output signal of the microcomputer 7. The decompression means 4 is constituted by, for example, an exhaust valve that exhausts air or the like in the cuff 1 at a slow speed and rapidly. This exhaust valve is fully opened at the end of blood pressure measurement based on the output signal of the microcomputer 7 and rapidly depressurizes the cuff 1. Note that the decompression means 4 may have a configuration including a slow exhaust valve that exhausts air or the like in the cuff 1 at a slow speed, and a quick exhaust valve that exhausts the air quickly.

  The display means 5 displays the maximum blood pressure value and the minimum blood pressure value determined by the microcomputer 7. The display unit 5 includes, for example, a liquid crystal display panel and a control unit that performs display control of the liquid crystal display panel. The display means 5 may be configured to display the pulse rate and time.

  The operation means 6 has various buttons and switches that are operated by the user during blood pressure measurement. For example, a measurement start button also serving as a power button, a user ID button for inputting a user identifier, a switch for setting a pressurization value, a memory button for storing a measurement result, and the like are provided. Yes.

  The microcomputer 7 implements the pressurization control means 11, the decompression control means 12, the blood pressure value determination means 13, the control initial value adjustment means 14, and the pulse wave detection means 15 by executing the blood pressure measurement program. The pressurization control means 11 performs drive control of the pump constituting the pressurization means 3 based on the pressure value in the cuff 1 detected by the pressure detection means 2. For example, when the pressure in the cuff 1 reaches a predetermined pressure during the pressurization of the cuff 1, the pressurization control unit 11 stops the pump.

  The decompression control unit 12 controls the opening degree of the exhaust valve based on the initial control value when the cuff 1 is started to be depressurized at a slow speed after the pressurization of the cuff 1 is completed. And the decompression control means 12 controls the opening degree of the exhaust valve so that the decompression speed approaches the target decompression speed based on the pressure value in the cuff 1 detected by the pressure detection means 2 during the slow decompression of the cuff 1. To do. Further, the decompression control means 12 fully opens the exhaust valve at the end of blood pressure measurement.

  Here, although not particularly limited, for example, the exhaust valve is driven by a pulse width modulated drive signal. In this case, the initial control value for controlling the opening degree of the exhaust valve at the start of decompression and the control value for controlling the opening degree of the exhaust valve during decompression are represented by digital values corresponding to the pulse width. The decompression control means 12 controls the opening degree of the exhaust valve by changing the digital value and changing the duty of the exhaust valve drive signal.

  Although not particularly limited, for example, the exhaust valve of the pressure reducing means 4 has a smaller opening degree as the control value is larger, and opens more as the control value is smaller. Therefore, if the control value is large, the depressurization speed of the cuff 1 is decreased, and if the control value is small, the depressurization speed of the cuff 1 is increased. For example, when the control value is zero, the exhaust valve is fully opened and the cuff 1 is rapidly exhausted.

  The control initial value adjusting means 14 adjusts the control initial value based on the pressure value in the cuff 1 detected by the pressure detecting means 2 during the slow depressurization of the cuff 1. The control initial value updated by this adjustment is used as the control initial value at the start of decompression of the next blood pressure measurement. That is, in the electronic sphygmomanometer according to the embodiment, the decompression control unit 12 controls the opening degree of the exhaust valve at the start of decompression of the current blood pressure measurement based on the control initial value updated at the previous blood pressure measurement.

  The pulse wave detection means 15 detects a pulse wave component included in the output signal of the pressure detection means 2 when the cuff 1 is depressurized at a slow speed. Based on the pulse wave component detected by the pulse wave detection means 15, the blood pressure value determination means 13 determines a maximum blood pressure value and a minimum blood pressure value by, for example, a blood pressure determination algorithm based on a known oscillometric method. The determined blood pressure value is displayed on the display means 5. Further, when the blood pressure value determining means 13 determines the blood pressure value, the blood pressure value determining means 13 notifies the decompression control means 12 of the end of measurement in order to fully open the exhaust valve.

  FIG. 2 is a block diagram showing the configuration of the control initial value adjusting means. As shown in FIG. 2, the control initial value adjusting means 14 includes an elapsed time determining means 21, a decompression speed calculating means (hereinafter simply referred to as a decompression speed calculating means) 22 when a predetermined time has elapsed since the start of decompression, and a decompression speed deviation. Calculation means 23, pressure drop amount calculation means (hereinafter simply referred to as pressure drop amount calculation means) 24 when a predetermined time has elapsed from the start of pressure reduction, control initial value correction amount determination means 25, control initial value correction amount table 26, control Initial value correction means 27 and control initial value storage means 28 are provided.

  The elapsed time determination means 21 determines that a predetermined time (for example, 1 second or 2 seconds) has elapsed from the start of the pressure reduction of the cuff 1. The elapsed time is obtained by subtracting the decompression start time from the current time. Specifically, for example, the elapsed time determination means 21 is predetermined from the start of pressure reduction when a specific routine in the pressure reduction processing routine is processed a predetermined number of times by the microcomputer 7 in the pressure reduction processing routine of the blood pressure measurement program. A step for determining that the time has elapsed is described, and this is realized by the microcomputer 7 processing the step.

  Thus, when determining the elapsed time by software processing, the decompression start time is the time when the decompression processing routine is started and is zero. The current time is the time when the microcomputer 7 has processed a specific routine in the decompression process routine a predetermined number of times. The elapsed time from the start of decompression is the time required for the microcomputer 7 to process a specific routine in the decompression process routine a predetermined number of times.

  Here, the decompression processing routine is a program for decompressing the cuff 1, and is executed by the microcomputer 7 after the end of the pressurization processing routine that is a program for pressurizing the cuff 1. Instead of determining the elapsed time based on the description of such a program, a counter, a timer, or the like may be provided in the electronic sphygmomanometer so as to measure the time.

  The decompression speed calculation means 22 calculates the decompression speed of the cuff 1 when it is determined by the elapsed time determination means 21 that a predetermined time has elapsed since the start of decompression. The decompression speed is obtained by, for example, differentiating the pressure value in the cuff 1 detected by the pressure detection means 2. The decompression speed deviation calculating means 23 calculates a deviation (speed deviation) of the decompression speed calculated by the decompression speed calculating means 22 from the target decompression speed. The speed deviation is obtained by subtracting the target decompression speed from the current decompression speed.

  The pressure drop amount calculating unit 24 calculates the amount of decrease in the pressure in the cuff 1 from the start of depressurization when the elapsed time determining unit 21 determines that a predetermined time has elapsed from the start of depressurization. The pressure drop amount is obtained by subtracting the current pressure value in the cuff 1 from the pressure value in the cuff 1 at the start of pressure reduction. The control initial value correction amount table 26 defines the relationship among the speed deviation, the pressure drop amount, the target pressure reduction speed, and the control initial value correction amount. The control initial value correction amount table 26 is described in the blood pressure measurement program.

  FIG. 3 shows an example of the control initial value correction amount table. Here, the speed deviation, the pressure drop amount, and the target pressure reduction speed are ΔV [mmHg / sec], P [mmHg], and R [mmHg / sec], respectively. In the control initial value correction amount table 26 shown in FIG. 3, for example, when ΔV is smaller than −4, if [P ≦ 0.5 × R], the control initial value correction amount is −5, and [ If 0.5 × R <P ≦ R], the correction amount of the control initial value is −4. When ΔV is larger than 4, if [R <P ≦ 1.5 × R], the correction amount of the control initial value is +4, and if [1.5 × R <P], the control initial value is set. The value correction amount is +5.

  That is, in the control initial value correction amount table 26, when the pressure reduction speed of the cuff 1 is smaller than the target pressure reduction speed, in order to increase the opening degree of the exhaust valve and increase the pressure reduction speed, the control value is made smaller. Conversely, when the pressure reduction speed of the cuff 1 is larger than the target pressure reduction speed, a correction amount is defined so as to increase the control value in order to reduce the opening degree of the exhaust valve and reduce the pressure reduction speed. . Further, the correction amount is defined such that the control value is smaller when the pressure drop amount is small, and conversely the control value is larger when the pressure drop amount is large. Note that the correction amount of the control initial value when ΔV is other values is as shown in FIG. 3 and is not shown here.

  The control initial value correction amount determining means 25 refers to the control initial value correction amount table 26 and corresponds to the speed deviation calculated by the pressure reduction speed deviation calculating means 23 and the pressure drop amount calculated by the pressure drop amount calculating means 24. Determine the correction amount of the initial control value. The control initial value correction means 27 corrects the control initial value based on the correction amount determined by the control initial value correction amount determination means 25. For example, the control initial value correction means 27 reads the control initial value stored in the control initial value storage means 28 and adds the correction amount determined by the control initial value correction amount determination means 25 to the control initial value. .

  The control initial value storage means 28 stores the control initial value corrected by the control initial value correction means 27. The control initial value storage means 28 is constituted by a memory in the microcomputer 7. The decompression control unit 12 reads the control initial value from the control initial value storage unit 28 at the start of decompression of the next blood pressure measurement.

  Here, the reason for considering both the speed deviation and the pressure drop amount when determining the correction amount of the control initial value will be described. When measuring the blood pressure during the decompression of the cuff 1, it is desirable to perform the measurement at a stable decompression speed in order to reliably detect the pulse wave. For example, control may be performed so that measurement is performed at a constant decompression speed, or decompression may be controlled while changing the target decompression speed according to the pressure of the cuff 1. In order to finish the blood pressure measurement in as short a time as possible, it is necessary to reach the pressure reduction speed suitable for blood pressure measurement, that is, the target pressure reduction speed in the shortest possible time after the start of the pressure reduction of the cuff 1. Further, in order to detect a pulse wave immediately after the start of decompression of the cuff 1, it is necessary to reach the target decompression speed with the pressure in the cuff 1 as high as possible. Therefore, it is necessary to consider both the speed deviation and the pressure drop.

  As a result of repeated studies by the present inventors, it has been found that there is an appropriate range for the opening degree of the exhaust valve at the start of the pressure reduction of the cuff 1. If the opening of the exhaust valve is smaller than the appropriate range, it takes a long time to reach the target decompression speed, and the measurement time becomes long. On the other hand, if the opening degree of the exhaust valve is too large, the amount of pressure drop immediately after the start of decompression becomes too large, which is not suitable for blood pressure measurement. In the experiments of the present inventors, in the combination of a specific cuff and an exhaust valve, when the opening degree of the exhaust valve at the start of pressure reduction of the cuff 1 is about 30 to 40%, the pressure drop amount is the shortest in the shortest time. The target decompression speed was reached in a small state.

  FIG. 4 is a flowchart showing a procedure after the start of decompression in the blood pressure measurement procedure of the electronic sphygmomanometer according to the first embodiment of the present invention. A series of procedures shown in FIG. 4 is started when the cuff 1 is pressurized and the pressure in the cuff 1 reaches a predetermined pressure. As shown in FIG. 4, when the pressure reduction of the cuff 1 is started, the pressure reduction control means 12 first reads the control initial value from the control initial value storage means 28 (step S1). Next, the decompression control unit 12 sets the control initial value read from the control initial value storage unit 28 to the control value at the start of the current decompression (step S2).

  Next, the blood pressure is measured by a known blood pressure determination algorithm (step S3). At the start of the decompression of the cuff 1, the exhaust valve of the decompression means 4 is opened by the decompression control means 12 corresponding to the control value (the control initial value read from the control initial value storage means 28) set in step S2. Set to At this time point, it is immediately after the start of decompression, and the maximum blood pressure value and the minimum blood pressure value are not determined (step S4: No). Therefore, the decompression control means 12 executes a known decompression control algorithm, and performs decompression control based on the pressure value in the cuff 1 detected by the pressure detection means 2 (step S5).

  Next, the control initial value adjusting means 14 determines whether or not the control initial value has been adjusted (step S6). If the control initial value has been adjusted (step S6: Yes), the process returns to the blood pressure measurement in step S3. On the other hand, if the control initial value is not adjusted (step S6: No), the control initial value adjusting means 14 performs a control initial value adjusting process described later (step S7), and returns to the blood pressure measurement in step S3. Then, blood pressure measurement is continued, and when the maximum blood pressure value and the minimum blood pressure value are determined by the blood pressure value determination means 13 (step S4: Yes), the exhaust valve of the decompression means 4 is fully opened and the cuff 1 is rapidly exhausted. A series of decompression processes shown in FIG.

  FIG. 5 is a flowchart showing a control initial value adjustment procedure of the electronic sphygmomanometer according to the first embodiment of the present invention. When the control initial value adjustment process is started in step S7 of FIG. 4, first, the elapsed time determination means 21 obtains the elapsed time (T) from the start of the pressure reduction of the cuff 1 (step S11), and the elapsed time (T ) Has reached the set value (step S12). Here, in order to clearly indicate that the subsequent processing is to be performed when the elapsed time from the start of decompression of the cuff 1 reaches a predetermined time, the elapsed time is determined in step S11 and step S12. As described above, the elapsed time (T) reaches the set value when the microcomputer 7 processes a specific routine in the decompression process routine a predetermined number of times.

  If the elapsed time (T) from the start of pressure reduction of the cuff 1 does not reach the set value (step S12: No), the series of control initial value adjustment processing shown in FIG. When the elapsed time (T) from the start of depressurization of the cuff 1 reaches the set value (step S12: Yes), the depressurization rate when the predetermined time has elapsed from the start of depressurization of the cuff 1 is calculated by the depressurization rate calculating means 22. (Step S13). Next, the speed deviation (ΔV) is calculated by the decompression speed deviation calculating means 23 (step S14). Further, the pressure drop amount calculation means 24 calculates the pressure drop amount (P) when a predetermined time has elapsed from the start of the pressure reduction of the cuff 1 (step S15).

  Based on the speed deviation (ΔV) and the pressure drop amount (P) calculated in Steps S14 and S15, the control initial value correction amount determination means 25 reads the corresponding control initial value from the control initial value correction amount table 26. Is read (step S16). Next, the control initial value correcting means 27 reflects the correction amount read in step S16 on the current control initial value to newly set the control initial value (step S17). The control initial value correcting means 27 stores the new control initial value in the control initial value storage means 28 (step S18). Then, a series of control initial value adjustment processes shown in FIG.

  FIG. 6 is a characteristic diagram showing an example of the effect when the initial control value is corrected, and shows the relationship between the pressure in the cuff 1 and the speed deviation of the decompression speed, and the relationship between time and the pressure in the cuff 1, respectively. ing. In FIG. 6, “first time” means that the cuff 1 is decompressed when the initial control value is a value (design value) at the time of shipment from the factory, and is “11th time”. Is the one in which the cuff 1 is decompressed after the control initial value has already been corrected 10 times.

  From FIG. 6, it can be seen that by correcting the control initial value, the pressure of the cuff 1 decreases in a state close to a straight line in a shorter time after the start of the decompression of the cuff 1.

Embodiment 2. FIG.
In the second embodiment, the initial control value is corrected based on the time required for the cuff pressure reduction speed to reach the target pressure reduction speed and the cuff pressure drop amount. The overall configuration of the sphygmomanometer is the same as that shown in FIG. However, in the following description, since the configuration of the control initial value adjusting unit is different from that of the first embodiment, the reference numeral of the control initial value adjusting unit is “34”.

  FIG. 7 is a block diagram showing the configuration of the control initial value adjusting means of the electronic sphygmomanometer according to the second embodiment of the present invention. As shown in FIG. 7, the control initial value adjusting means 34 includes a decompression speed calculating means 41, a decompression speed deviation calculating means 42, a target decompression speed arrival determining means 43, an elapsed time calculating means (hereinafter simply referred to as a target decompression speed arrival means). 44, an elapsed time calculation means), a pressure drop amount calculation means (hereinafter simply referred to as a pressure drop amount calculation means) 45, a control initial value correction amount determination means 46, and a control initial value correction means. 47 and a control initial value storage means 48.

  The decompression speed calculation means 41 calculates the decompression speed of the cuff 1 during the decompression of the cuff 1 based on the pressure value in the cuff 1 detected by the pressure detection means 2. The decompression speed deviation calculating means 42 is the same as the decompression speed deviation calculating means 23 of the first embodiment. The target decompression speed arrival determination means 43 determines whether or not the decompression speed of the cuff 1 has reached the target decompression speed. For example, the target decompression speed arrival determination unit 43 determines that the decompression speed of the cuff 1 is the target when the absolute value of the speed deviation of the decompression speed calculated by the decompression speed deviation calculation unit 42 is equal to or less than a preset allowable value. It is determined that the decompression speed has been reached.

  The elapsed time calculation means 44 calculates the elapsed time from the start of pressure reduction until the target pressure reduction speed arrival determination means 43 determines that the target pressure reduction speed has been reached. For example, the elapsed time calculation unit 44 calculates the elapsed time by software processing, similar to the elapsed time determination unit 21 of the first embodiment. The pressure drop amount calculation means 45 is the same as the pressure drop amount calculation means 24 of the first embodiment in that the pressure in the cuff 1 until the target pressure reduction speed arrival determination means 43 determines that the target pressure reduction speed has been reached. Calculate the amount of descent from the start of decompression.

  Based on the elapsed time calculated by the elapsed time calculating unit 44 and the pressure drop calculated by the pressure drop calculating unit 45, the control initial value correction amount determining unit 46 calculates the control initial value correction amount from a predetermined relational expression. To decide. When the elapsed time and pressure drop amount from the start of the pressure reduction of the cuff 1 to the target pressure reduction speed are T and P, respectively, and α and β are coefficients set according to the target pressure reduction speed, the relational expression is Although not particularly limited, for example, it is represented by [α × P−β × T].

  This relational expression and the coefficients α and β are described in the blood pressure measurement program. For example, when the target decompression speed is 10 mmHg / sec, α and β are 0.1 and 1.0, respectively. The control initial value correcting means 47 and the control initial value storing means 48 are the same as the control initial value correcting means 27 and the control initial value storing means 28 of the first embodiment, respectively. The procedure after the start of decompression in the blood pressure measurement procedure of the electronic sphygmomanometer according to the second embodiment is the same as the flowchart shown in FIG. Therefore, the description is omitted.

  FIG. 8 is a flowchart showing a control initial value adjustment procedure of the electronic sphygmomanometer according to the second embodiment of the present invention. When the control initial value adjustment process is started in step S7 of FIG. 4, first, the pressure reduction speed of the cuff 1 is calculated by the pressure reduction speed calculation means 41 (step S21). Next, the speed deviation (ΔV) of the decompression speed is calculated by the decompression speed deviation calculating means 42 (step S22). Next, the target pressure reduction speed attainment determination unit 43 determines whether or not the absolute value of the speed deviation (ΔV) is equal to or less than an allowable value (step S23).

  When the absolute value of the speed deviation (ΔV) exceeds the allowable value (step S23: No), the series of control initial value adjustment processes shown in FIG. When the absolute value of the speed deviation (ΔV) is equal to or less than the allowable value (step S23: Yes), the elapsed time (T) from the start of the cuff 1 decompression to the current time is calculated by the elapsed time calculation means 44 ( Step S24). Further, the pressure drop amount calculating means 45 calculates the pressure drop amount (P) in the cuff 1 from the start of the pressure reduction of the cuff 1 to the present time (step S25).

  Then, the control initial value correction amount determination means 46 calculates the correction amount of the control initial value from the relational expression described above based on the elapsed time (T) and the pressure drop amount (P) calculated in steps S24 and S25. (Step S26). Next, the control initial value correcting unit 47 reflects the correction amount calculated in step S26 on the current control initial value to newly set the control initial value (step S27), and stores it in the control initial value storage unit 48. Store (step S28). Then, a series of control initial value adjustment processing shown in FIG. 8 ends.

  As described above, according to each embodiment, the control initial value is adjusted by the control initial value adjusting means 14 and 34 based on the pressure in the cuff 1 detected during the decompression of the cuff 1. At the start of the pressure reduction of the next blood pressure measurement, the opening degree of the exhaust valve of the pressure reducing means 4 is controlled based on the initial control value adjusted at the time of the pressure reduction of the current blood pressure measurement. The opening degree of the exhaust valve at the start of decompression is in an appropriate state according to the change with time of the valve or the individual difference of the electromagnetic valve. Accordingly, since the pressure reduction of the cuff 1 is always started at a pressure reduction speed close to the target value, it is possible to prevent a pulse wave detection omission immediately after the pressure reduction starts and a prolonged blood pressure measurement.

  As described above, the present invention is not limited to the above-described embodiment, and various modifications can be made. For example, the numerical values described in the description of the embodiments and the accompanying drawings are examples, and the present invention is not limited to these values. In the embodiment, an example in which the exhaust valve is driven by a pulse width modulated drive signal has been described. However, the exhaust valve may be driven by another drive method.

  As described above, the electronic sphygmomanometer according to the present invention is useful for an electronic sphygmomanometer that measures blood pressure when the cuff is depressurized, and particularly for an electronic sphygmomanometer that controls the depressurization speed of the cuff during blood pressure measurement. Is suitable.

It is a block diagram which shows the whole structure of the electronic blood pressure monitor concerning Embodiment 1 of this invention. It is a block diagram which shows the structure of the control initial value adjustment means of the electronic blood pressure monitor concerning Embodiment 1 of this invention. It is a graph which shows an example of the control initial value correction amount table of the electronic blood pressure monitor concerning Embodiment 1 of this invention. It is a flowchart which shows the blood-pressure measurement procedure of the electronic sphygmomanometer concerning Embodiment 1 of this invention. It is a flowchart which shows the control initial value adjustment procedure of the electronic blood pressure monitor concerning Embodiment 1 of this invention. It is a characteristic diagram which shows the relationship between time and the pressure in a cuff by comparing the presence or absence of correction of a control initial value. It is a block diagram which shows the structure of the control initial value adjustment means of the electronic blood pressure monitor concerning Embodiment 2 of this invention. It is a flowchart which shows the control initial value adjustment procedure of the electronic blood pressure monitor concerning Embodiment 2 of this invention.

Explanation of symbols

1 Cuff 2 Pressure detection means 4 Pressure reduction means 12 Pressure reduction control means 14, 34 Control initial value adjustment means 21 Elapsed time determination means 22, 41 Pressure reduction speed calculation means 23, 42 Pressure reduction speed deviation calculation means 24, 45 Pressure drop amount calculation means 25 , 46 Control initial value correction amount determination means 26 Control initial value correction amount table 27, 47 Control initial value correction means 28, 48 Control initial value storage means 43 Target decompression speed arrival determination means 44 Elapsed time calculation means

Claims (6)

With cuff,
Pressure reducing means for reducing the pressure in the cuff;
Decompression control means for controlling the decompression means based on a control value;
Pressure detecting means for detecting the pressure in the cuff;
Control value adjusting means for correcting the control value for the next time of pressure reduction based on the pressure in the cuff detected by the pressure detecting means when the pressure in the cuff is being reduced by the pressure reducing means; ,
An electronic blood pressure monitor comprising:   The electronic sphygmomanometer according to claim 1, wherein the control value is a control initial value for the decompression control unit to control the decompression unit at the start of decompression. The control value adjusting means is
Elapsed time determination means for determining whether the elapsed time from the start of decompression matches the set value;
A decompression speed calculating means for calculating a decompression speed at a time when it is determined by the elapsed time determining means that a predetermined time has elapsed from the start of decompression;
Decompression speed deviation calculating means for calculating a deviation of the decompression speed calculated by the decompression speed calculating means from a target decompression speed;
A pressure drop amount calculating means for calculating a decrease amount from the pressure reduction start of the pressure in the cuff at a time when it is determined by the elapsed time determination means that a predetermined time has elapsed from the pressure reduction start;
A control initial value correction amount determination means for determining a correction amount of the control initial value based on the speed deviation calculated by the pressure reduction speed deviation calculation means and the pressure drop amount calculated by the pressure drop amount calculation means;
Control initial value correction means for correcting the control initial value based on the correction amount determined by the control initial value correction amount determination means;
Control initial value storage means for storing the control initial value corrected by the control initial value correction means;
The electronic blood pressure monitor according to claim 2, further comprising: A control initial value correction amount table that defines the relationship between the deviation of the decompression speed from the target decompression speed, the amount of pressure drop from the start of decompression, the target decompression speed and the correction amount of the control initial value;
The electronic sphygmomanometer according to claim 3, wherein the control initial value correction amount determining means further determines a correction amount of the control initial value based on the control initial value correction amount table. The control value adjusting means is
Decompression speed calculation means for calculating the decompression speed during decompression;
Decompression speed deviation calculating means for calculating a deviation of the decompression speed calculated by the decompression speed calculating means from a target decompression speed;
A target decompression speed attainment judging means for judging that the decompression speed has reached the target decompression speed;
Elapsed time calculation means for calculating an elapsed time from the start of pressure reduction until it is determined by the target pressure reduction speed arrival determination means that the target pressure reduction speed is reached;
A pressure drop amount calculating means for calculating a decrease amount from the start of pressure reduction of the pressure in the cuff until it is determined by the target pressure reducing speed arrival determining means that the target pressure reducing speed is reached;
A control initial value correction amount determining means for determining a correction amount of the control initial value based on the elapsed time calculated by the elapsed time calculating means and the pressure drop amount calculated by the pressure drop amount calculating means;
Control initial value correction means for correcting the control initial value based on the correction amount determined by the control initial value correction amount determination means;
Control initial value storage means for storing the control initial value corrected by the control initial value correction means;
The electronic blood pressure monitor according to claim 2, further comprising:   The control initial value correction amount determination means determines the correction amount of the control initial value based on a relational expression of a pressure drop amount from the start of pressure reduction, an elapsed time from the start of pressure reduction, and a correction amount of the control initial value. The electronic blood pressure monitor according to claim 5.

Images