JP2008188303A - Electronic sphygmometer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To judge insufficient pressurization as needed and to judge the insufficient pressurization corresponding to the probability of pulse wave information extracted in the pressurizing process of a cuff. <P>SOLUTION: The electronic sphygmometer comprises: a cuff 1; a pressurizing means 2 for pressurizing the cuff 1; a depressurizing means 4 for depressurizing the cuff 1; a pressure detection means 5 for detecting the pressure of the cuff 1; a pulse wave component detection means 11 for detecting pulse wave components superimposed on cuff pressure signals detected by the pressure detection means 5; a pulse wave amplitude value calculation means 12 for calculating a pulse wave amplitude value from the pulse wave components detected by the pulse wave component detection means 11; and an insufficient pressurization judgement means 20 for judging that the cuff pressure is sufficient when the pulse wave amplitude value captured in the initial period of a depressurizing process is equal to or smaller than a threshold and judging that the cuff pressure is insufficient when it is not so. When the probability of the pulse wave information extracted in the pressurizing process is extremely high, the insufficient pressurization judgement means 20 does not judge the insufficient pressurization. Also, the threshold is changed corresponding to the probability of the pulse wave information extracted in the pressurizing process of the cuff 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an oscillometric electronic sphygmomanometer, and more particularly to an electronic sphygmomanometer that measures blood pressure during cuff decompression.

  Conventionally, an oscillometric electronic sphygmomanometer that measures blood pressure during decompression of the cuff pressurizes the cuff to a predetermined pressure value that is estimated to be higher than the maximum blood pressure value, and then gradually reduces the pressure. The cuff pressure (hereinafter referred to as cuff pressure) is detected in the process, and the blood pressure is determined based on the pulse wave component included in the cuff pressure signal. Therefore, accurate blood pressure cannot be determined even when the process proceeds to the pressure reduction process with insufficient cuff pressurization. In view of this, an electronic sphygmomanometer having a function of determining whether or not the pressure state of the cuff is sufficient at the initial stage of the pressure reduction process after the pressurization of the cuff has been proposed.

  For example, it has a function of comparing the amplitude of the pulse wave component immediately after the start of measurement (hereinafter referred to as pulse wave amplitude) with a reference value, and determining that pressurization is insufficient if the pulse wave amplitude exceeds the reference value. The first electronic sphygmomanometer is known (for example, see Patent Document 1). In Patent Document 1, the reference value is assumed to be the maximum value of the pulse wave amplitude at the highest possible blood pressure. In addition, the function of determining the ratio between the maximum value of the pulse wave amplitude during the decompression process of the cuff and the pulse wave amplitude immediately after the start of measurement and determining that the pressure is insufficient when the ratio value does not reach the determination value. A second electronic sphygmomanometer is known (for example, see Patent Document 1).

  Furthermore, the maximum value of the pulse wave amplitude extracted during cuff pressurization is detected, a threshold value is calculated based on the maximum value, and this threshold value and the pulse wave amplitude captured at the beginning of the cuff decompression process are calculated. In comparison, if the pulse wave amplitude detected immediately after the transition to the decompression process is smaller than the threshold value, it is determined that the cuff pressurization is sufficient. Is known (for example, see Patent Document 2).

JP-A-61-128939 (2. Claims (1) and (4)) JP-A-5-111468 ([Claim 1] of [Claims])

  However, the first sphygmomanometer has a problem that the accuracy of determination of insufficient pressurization is low because there are some people whose reference values are appropriate and others who are not, depending on individual differences among subjects. In the second sphygmomanometer, since it is necessary to continue the decompression until the maximum value of the pulse wave amplitude is detected after the transition to the decompression process of the cuff, the time required for the determination of insufficient pressurization becomes longer. There is a problem that it causes pain.

  Further, in the third sphygmomanometer, since the pressurization rate is generally higher than the depressurization rate, it is not always possible to accurately extract the pulse wave during pressurization. If the extracted pulse wave is not accurate, an accurate threshold value cannot be obtained, and there is a problem that the determination accuracy of insufficient pressurization is low.

  An object of the present invention is to provide an electronic sphygmomanometer that determines the lack of pressurization as necessary in order to eliminate the above-described problems caused by the conventional technology. It is another object of the present invention to provide an electronic sphygmomanometer that determines the lack of pressurization according to the likelihood of pulse wave information extracted during the cuff pressurization process.

  In order to solve the above-described problems and achieve the object, an electronic sphygmomanometer according to the invention of claim 1 includes a cuff, a pressurizing unit that pressurizes the cuff, and a depressurizing unit that depressurizes the cuff after pressurization is completed. An underpressure determining means for determining whether cuff pressure is insufficient in the cuff depressurization process, wherein the underpressure determination is performed according to pulse information extracted in the cuff pressurization process The determination by means is not performed.

  An electronic sphygmomanometer according to a second aspect of the present invention is the electronic blood pressure monitor according to the first aspect, wherein the pulse wave information is detected from a pressure detection means for detecting the pressure of the cuff and a cuff pressure signal detected by the pressure detection means. A pulse wave information detecting means for detecting pressure, a pressurization stop pressure calculating means for calculating a pressurization stop pressure from the pulse wave information, and a pressurization stop pressure estimation for calculating the accuracy of the pressurization stop pressure from the pulse wave information. An accuracy calculation unit, and the determination by the underpressure determination unit is not performed according to the accuracy of the pressurization stop pressure.

  An electronic sphygmomanometer according to a third aspect of the invention is the electronic blood pressure monitor according to the second aspect, wherein the pulse wave component superimposed on the cuff pressure signal detected by the pressure detecting means is detected and the detected pulse wave is detected. Pulse wave amplitude information calculating means for calculating pulse wave amplitude information from a component, wherein the under-pressurization determining means compares the pulse wave amplitude information captured in the cuff decompression process with a threshold value, and It is determined that the cuff pressure is sufficient when the pulse wave amplitude information is equal to or less than the threshold value, and it is determined that the cuff pressure is insufficient when the pulse wave amplitude information is greater than the threshold value. To do.

  According to a fourth aspect of the present invention, there is provided an electronic sphygmomanometer comprising a cuff, a pressurizing unit that pressurizes the cuff, a depressurizing unit that depressurizes the cuff after completion of pressurization, and a pressure detecting unit that detects the pressure of the cuff. A pulse wave amplitude information calculating unit that detects a pulse wave component superimposed on the cuff pressure signal detected by the pressure detecting unit and calculates pulse wave amplitude information from the detected pulse wave component; and a pressure reduction of the cuff A cuff pressure signal detected by the pressure detecting means in an electronic sphygmomanometer comprising: an underpressure determining unit that determines whether the cuff pressure is insufficient by comparing the pulse wave amplitude information captured in the process with a threshold value The accuracy of the pulse wave information is calculated from the pulse wave information, and the threshold value is changed according to the accuracy of the pulse wave information.

  An electronic sphygmomanometer according to a fifth aspect of the present invention is the electronic sphygmomanometer according to the fourth aspect, wherein the pulse wave information detecting means detects pulse wave information from the cuff pressure signal detected by the pressure detecting means; Pressurization stop pressure calculating means for calculating the pressurization stop pressure from the wave information; and pressurization stop pressure estimation accuracy calculating means for calculating the accuracy of the pressurization stop pressure from the pulse wave information. The threshold value is changed according to the accuracy of the pressure stop pressure.

  An electronic blood pressure monitor according to a sixth aspect of the present invention is the electronic blood pressure monitor according to the fourth or fifth aspect, wherein the insufficient pressurization determining means is configured to detect cuff pressure when the pulse wave amplitude information is equal to or less than the threshold value. Is determined to be sufficient, and when the pulse wave amplitude information is larger than the threshold value, it is determined that the cuff pressure is insufficient.

  An electronic blood pressure monitor according to a seventh aspect of the present invention is the electronic blood pressure monitor according to any one of the first to sixth aspects, wherein the pulse wave information includes a pulse wave number and a pulse wave extracted during the pressurizing process of the cuff. And one or more types of information among the calculated pulse wave amplitude values.

  According to an eighth aspect of the present invention, in the electronic blood pressure monitor according to any one of the first to seventh aspects, the pulse wave amplitude information includes a pulse wave amplitude value, a pulse wave area, or a pulse wave amplitude derivative. It is one or more types of information among values.

  According to the first aspect of the present invention, since the determination of insufficient pressurization is not performed according to the pulse information extracted during the pressurization process of the cuff, the determination of insufficient pressurization is performed as necessary. For example, when the probability of the pulse information extracted during the cuff pressurization process is very high, the determination of insufficient pressurization is not performed. Therefore, useless processing is not performed. Conventionally, if noise larger than the threshold value occurs due to the influence of body movement or the like in the early stage of the decompression process, it is determined that the pressurization is insufficient, so that it is not actually necessary to repressurize the cuff. Nevertheless, there was a problem that re-pressurization was performed. On the other hand, according to the invention of claim 1, since the determination of insufficient pressurization is not performed according to the pulse information extracted in the cuff pressurization process, the error due to the influence of such noise is not performed. Judgment is lost. Therefore, unnecessary repressurization is not performed.

  According to the fourth aspect of the present invention, the threshold value used for the determination of insufficient pressurization is calculated based on the probability of the pulse information extracted in the cuff pressurization process. Since the determination of insufficient pressurization is performed using this threshold value, the determination of insufficient pressurization is performed according to the probability of the pulse information extracted during the cuff pressurization process. For example, when the probability of the pulse information extracted during the cuff pressurization process is high, the threshold value is increased, so that it is difficult to determine that pressurization is insufficient, and when the probability is low, the threshold is set. Since the value is lowered, it is easily determined that the pressure is insufficient. That is, the determination of insufficient pressurization is not performed more strictly than necessary.

  According to the electronic sphygmomanometer according to the present invention, there is an effect that it is possible to determine the lack of pressurization as necessary. In addition, there is an effect that it is possible to change the condition for determining the lack of pressurization according to the probability of the pulse wave information extracted during the cuff pressurization process.

  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.

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

  The microcomputer 6 includes a pressurization control means 21, a quick exhaust control means 22, a decompression control means 23, a pulse wave component detection means 11, a pulse wave amplitude value calculation means 12, a blood pressure value determination means 13, and a pressurization pulse wave information detection means. 15, a pressurization stop pressure calculating unit 17, a pressurization stop pressure estimation accuracy calculating unit 18, a threshold value calculating unit 19, and a pressurization insufficient determining unit 20. These means constituting the microcomputer 6 are realized by the microcomputer 6 executing a pressure measurement program.

  The pressurization control means 21 controls the pressurization means 2 (a pump for sending a fluid such as air to the cuff 1) that pressurizes the cuff 1 based on the output signal of the pressure detection means 5 to control the pressurization speed of the cuff 1. Control. Further, the pressurization control unit 21 controls to stop pressurization based on the output signal of the pressurization stop pressure calculating unit 17. Further, the pressurization control means 21 controls to pressurize the cuff 1 again based on the output signal of the pressurization insufficient determination means 20.

  The rapid exhaust control unit 22 controls the rapid exhaust unit 3 (a rapid exhaust valve or the like that rapidly exhausts air or the like in the cuff 1) based on the notification from the blood pressure value determination unit 13, and rapidly decompresses the cuff 1. . The decompression control means 23 controls the decompression means 4 (such as a slow exhaust valve that exhausts the air in the cuff 1 at a very low speed) based on the output signal of the pressurization stop pressure calculating means 17, and the slow speed of the pressure of the cuff 1. The decompression is started, and the decompression speed is controlled based on the output signal of the pressure detecting means 5.

  The pressure detection means 5 detects the pressure of the cuff 1. The pressure detection means 5 is comprised by the pressure sensor, for example. The display unit 7 displays the maximum blood pressure value and the minimum blood pressure value determined by the microcomputer 6. The display unit 7 includes, for example, a liquid crystal display panel and a control unit that performs display control of the liquid crystal display panel.

  The pressurizing pulse wave information detecting unit 15 detects pulse wave information included in the output signal of the pressure detecting unit 5 when the cuff 1 is pressurized by the pressurizing unit 2. At this time, the pulse wave information detected by the pressurizing pulse wave information detecting means 15 is a differential value (pressurization speed) of the pressure of the cuff 1. This is because the pressure fluctuation caused by the pulse detected when the cuff 1 is pressurized is so small that it is difficult to observe.

  FIG. 2 is a characteristic diagram showing the differential value of the cuff pressure in the pressurizing process, with the horizontal axis as the cuff pressure. In the example shown in FIG. 2, although not particularly limited, the pressurization speed is controlled to be 15 mmHg / sec. As shown in FIG. 2, by taking a differential value of the cuff pressure, minute pressure fluctuations can be observed, so that a pulse wave can be made obvious.

  The pressurization stop pressure calculating means 17 calculates the pressurization stop pressure for stopping the pressurization of the cuff 1 by the pressurizing means 2 based on the differential value of the cuff pressure detected by the pressurization pulse wave information detecting means 15. To do. For example, the pressurization stop pressure calculating means 17 sets the pressure obtained by adding 60 mmHg to the cuff pressure when the differential pulse wave amplitude value is maximized as the pressurization stop pressure. When the cuff pressure reaches the pressurization stop pressure when the cuff 1 is pressurized, the output signal of the pressurization stop pressure calculating means 17 is asserted. Thereby, the drive of the pressurizing means 2 is stopped, and instead, the slow exhaust valve constituting the decompression means 4 is opened, and the slow decompression of the cuff 1 is started.

  The pulse wave component detection means 11 detects the pulse wave component superimposed in the output signal of the pressure detection means 5 when the pressure of the cuff 1 is gradually reduced by the pressure reduction means 4. The pulse wave amplitude value calculating unit 12 calculates a pulse wave amplitude value in the decompression process based on the pulse wave component detected by the pulse wave component detecting unit 11. Based on the output signal of the pulse wave amplitude value calculation means 12 and the output signal of the pressure detection means 5, the blood pressure value determination means 13 determines the maximum blood pressure value and the minimum blood pressure value by a blood pressure determination algorithm based on a known oscillometric method. .

  When the blood pressure value is determined, the quick exhaust valve constituting the quick exhaust means 3 is opened, and the quick exhaust of the cuff 1 is started. In addition, the minimum blood pressure value and the maximum blood pressure value are displayed on the display unit 7.

  The pressurization stop pressure estimation accuracy calculation means 18 is based on the pulse wave information detected by the pressurization pulse wave information detection means 15 to determine how much the pressurization stop pressure is calculated by the pressurization stop pressure calculation means 17. That is, that is, the estimated accuracy of pressurization stop pressure (hereinafter referred to as pressurization stop pressure estimation accuracy) is calculated. The pulse wave information used at this time is based on the differential value of the pressure of the cuff 1, the pulse wave number extracted during the pressurizing process of the cuff 1, the pulse wave interval, and the calculated pulse wave amplitude value One or more types of information.

  As an example, the pressurization stop pressure estimation accuracy calculation means 18 determines the pressurization stop pressure estimation accuracy at the levels (1) to (5) according to the following criteria (1) to (5). (1) The number of differential pulse wave amplitude values equal to or greater than a set threshold value (for example, 10 mmHg / sec) among the pulse wave information detected by the pressurizing pulse wave information detection means 15 is counted, and the counted value Is 1 beat or zero. (2) The number of pulse waves having a differential pulse wave amplitude value greater than or equal to a set threshold value among the pulse wave information detected by the pressurizing pulse wave information detection means 15 is 2 or more, of which The differential pulse wave amplitude value of the last detected pulse wave is maximum. (3) The number of pulse waves having a differential pulse wave amplitude value greater than or equal to a set threshold value among the pulse wave information detected by the pressurizing pulse wave information detection means 15 is 2 beats or more, The differential pulse wave amplitude value of the pulse wave detected at the end of is not maximum. (However, the case that satisfies the criteria of (5) below is excluded.) (4) During re-pressurization. (5) The number of pulse waves having a differential pulse wave amplitude value greater than or equal to a set threshold value among the pulse wave information detected by the pressurizing pulse wave information detection means 15 is 3 beats or more, When the differential pulse wave amplitude value of the pulse wave detected at the end of the pulse wave is 50% or less of the maximum value of the differential pulse wave amplitude value of the pulse wave detected before that.

  In the example of FIG. 2, there are six pulse waves having a differential pulse wave amplitude value of 10 mmHg / sec or more, and a pulse wave U having a differential pulse wave amplitude value of 10 mmHg / sec or more detected last is 15 mmHg / sec. Since it is sec and is 50% or less of the differential pulse wave amplitude value of the pulse wave S (41 mmHg / sec) having the maximum amplitude value, the pressurization stop pressure estimation accuracy is applicable to the case of the above (5).

The threshold calculation unit 19 calculates a threshold based on the pressurization stop pressure estimation accuracy calculated by the pressurization stop pressure estimation accuracy calculation unit 18. For example, when the pressurization stop pressure estimation accuracy is (1) or (2), the threshold value is H _th150 mmHg. When the pressurization stop pressure estimation accuracy is (5), the threshold value calculation means 19 does not calculate the threshold value.

  When the pressurization stop pressure estimation accuracy is (3) or (4), the threshold value calculation means 19 determines a threshold value based on a threshold value setting table, for example, as described below. This threshold value setting table may be stored in a non-volatile memory built in the microcomputer 6, or may be described in a blood pressure measurement program executed by the microcomputer 6.

FIG. 3 is a chart showing an example of the threshold setting table, and FIG. 4 is a characteristic chart showing an example of the relationship between the pressurization stop pressure and the threshold. As shown in these figures, although not particularly limited, for example, the threshold when the pressurization stop pressure is less than ₁₅₀₀ mmHg is H _th150 mmHg, and the threshold when it is _180.0 mmHg or more is H _th180 mmHg ( > H _th150 mmHg).

The threshold value when the pressurization stop pressure is 150.0 mmHg or more and less than 180.0 mmHg is obtained by the following equation, where the pressurization stop pressure is P _STOP mmHg.
Threshold = (P _STOP −150) × (H _th180 −H _th150 ) / 30 + H _th150

The relationship between the pressurization stop pressure and the threshold value when the pressurization stop pressure is 150.0 mmHg or more and less than 180.0 mmHg is not limited to the above formula and can be variously changed. For example, in the pressure stop pressure range, or changed stepwise thresholds to _H th180 mmHg from _H th150 mmHg, may vary in a curve. Further, the critical value of the pressurization stop pressure may not be 150 mmHg or 180 mmHg.

  When the pressurization stop pressure estimation accuracy is other than (5), the under-pressurization determining unit 20 calculates the pulse wave amplitude value at the initial stage of the depressurization process and the threshold value calculated by the threshold value calculating unit 19. The pulse wave amplitude value calculated by the means 12 is compared. The under-pressurization determining means 20 determines that the cuff pressure is sufficient when the pulse wave amplitude value is less than or equal to the threshold value, and determines that the cuff pressure value is greater than the threshold value. It is determined that the pressure is insufficient.

  When the cuff pressure is insufficient, the output signal of the insufficient pressure determination means 20 is asserted. As a result, the slow exhaust valve constituting the pressure reducing means 4 is closed, and instead, the driving of the pressurizing means 2 is resumed, and repressurization of the cuff 1 is started. When the cuff pressure after the re-pressurization is sufficient, the cuff 1 is depressurized as it is. On the other hand, when the pressurization stop pressure estimation accuracy is (5), the underpressure determination unit 20 determines that the estimation accuracy of the pressurization stop pressure is very high, and does not determine the lack of pressurization.

  5 and 6 are flowcharts showing the blood pressure measurement procedure of the electronic sphygmomanometer according to the embodiment of the present invention, and FIG. 6 is a continuation of FIG. After the cuff 1 is wound around the upper arm of the measurer, as shown in FIG. 5, when the blood pressure measurement process is started, first, the pressurization stop pressure is set to the initial value A (step S1). This initial value A may be stored in a non-volatile memory built in the microcomputer 6, or may be described in a blood pressure measurement program executed by the microcomputer 6. Next, pressurization of the cuff 1 is started by the pressurizing means 2, and the upper arm of the measurer is pressed (step S2). And it is judged by the pressure detection means 5 and the pressurization pulse wave information detection means 15 whether the pulse wave at the time of pressurization was able to be detected (step S3).

  If the pulse wave cannot be detected (step S3: No), the process proceeds to step S9. When the pulse wave can be detected (step S3: Yes), the pulse wave information detecting means 15 at the time of pressurization calculates a differential pulse wave amplitude value (step S4). Then, the calculated differential pulse wave amplitude value and the corresponding pulse wave start pressure (the cuff pressure at the start point of the pulse wave) are stored in the memory in the microcomputer 6 (step S5). This memory is omitted in FIG.

  Subsequently, it is determined by the pressurization pulse wave information detection means 15 whether or not the differential pulse wave amplitude value calculated in step S4 is maximum (step S6). An area for storing the maximum value of the differential pulse wave amplitude value is provided in the memory in the microcomputer 6, and the maximum value of the differential pulse wave amplitude value stored in the area and the differential pulse wave amplitude value newly calculated in step S4 This determination is made by comparing However, when the differential pulse wave amplitude value is calculated for the first time, nothing is stored in the area on the memory in the microcomputer 6 that stores the maximum value of the differential pulse wave amplitude value. It is determined that the amplitude value is the maximum. If it is determined in step S6 that the differential pulse wave amplitude value calculated in step S4 is the maximum (step S6: Yes), the maximum value of the differential pulse wave amplitude value is updated (step S7). Then, the pressurization stop pressure calculating means 17 calculates the pressurization stop pressure (step S8), and the process proceeds to step S9.

  On the other hand, when the differential pulse wave amplitude value calculated in step S4 is not the maximum (step S6: No), step S7 is omitted and the process proceeds to step S8.

  In step S9, it is determined whether or not the current pressure of the cuff 1 is higher than the pressurization stop pressure calculated in step S8 (step S9). If it is higher (step S9: Yes), the pressurization stop pressure estimation accuracy calculation means 18 calculates the pressurization stop pressure estimation accuracy (step S10). Then, the pressurization of the cuff 1 by the pressurizing means 2 is finished (step S11). If the current pressure is not higher than the pressurization stop pressure (step S9: No), the process returns to step S2, and steps S2 to S9 are repeated until the current cuff pressure becomes higher than the pressurization stop pressure. Immediately after the start of pressurization or when the pressurization has progressed but no pulse wave can be detected in step S3 (step S3: No), the pressurization stop pressure in step S9 is the initial value A set in step S1. It becomes.

  When the pressurization of the cuff 1 is completed, the decompression means 4 starts the slow depressurization of the cuff 1 (step S12). And the pulse wave at the time of pressure reduction is extracted by the pulse wave component detection means 11 and the pulse wave amplitude value calculation means 12 (step S13). That is, the pulse wave component detection means 11 detects the pulse wave component included in the output signal of the pressure detection means 5, and based on the pulse wave component, the pulse wave amplitude value calculation means 12 calculates the pulse wave amplitude value. calculate.

  Next, based on the estimated accuracy information of the pressurization stop pressure given from the pressurization stop pressure estimation accuracy calculation unit 18, the underpressurization determination unit 20 determines whether or not it is necessary to determine the lack of pressurization. (Step S14). If it is necessary to determine the lack of pressurization (step S14: Yes), the lack of pressurization is determined (step S15). This determination procedure for insufficient pressurization will be described later.

  As a result of the determination, when it is determined that the pressurization is insufficient (step S15: Yes), a predetermined value α is added to the current pressurization stop pressure to obtain a new pressurization stop pressure (step S16). Here, the predetermined value α is, for example, a value of about 30 to 40 mmHg. Then, returning to step S2, the cuff 1 is re-pressurized to the new pressurization stop pressure set in step S16. However, in the case of repressurization, since it is not necessary to perform steps S3 to S8, steps S3 to S8 are omitted, and the process proceeds to step S9 following step S2.

  If it is determined in step S15 that the pressurization is sufficient (step S15: No), or if it is not determined in step S14 that the pressurization is insufficient (step S14: No), the cuff 1 continues to be depressurized at a low speed. The blood pressure value determining means 13 calculates the maximum blood pressure value and the minimum blood pressure value (step S17).

  When the maximum blood pressure value and the minimum blood pressure value are determined, the blood pressure measurement is terminated. When the measurement is finished (step S18: Yes), the quick exhaust means 3 performs quick exhaust of the cuff 1 (step S19). The maximum blood pressure value and the minimum blood pressure value are displayed on the display unit 7. Then, the series of blood pressure measurement processes described above is terminated. When the measurement is not finished (step S18: No), the process returns to step S12, and steps S12 to S18 are repeated.

  FIG. 7 is a flowchart showing the under-pressurization determination procedure in step S15 of FIG. As shown in FIG. 7, when the under-pressurization determination process is started, it is first determined whether or not it is a section for performing under-pressurization determination (step S21).

  This step 21 is provided in order to determine whether or not the pressurization is insufficient only during a certain period after the cuff 1 is started to depressurize at a low speed. This fixed period is, for example, an initial period of the depressurization process until the depressurization progresses by about 30 mmHg from the pressure of the cuff 1 at the start of the slow depressurization. After this fixed period, it is not necessary to determine whether the pressurization is insufficient.

  If it is not a section in which underpressurization determination is performed (step S21: No, if No in step S15 in FIG. 6), the process proceeds to step S17 in FIG. 6 to perform blood pressure measurement processing. If the current time is an interval for determining whether or not pressurization is insufficient (step S21: Yes), it is further determined whether or not, for example, it is within 2 beats after starting the slow depressurization of the cuff 1 (step S22). . If it is not within 2 beats (step S22: No, if No in step S15 in FIG. 6), the process proceeds to step S17 in FIG. 6 to perform blood pressure measurement processing.

  If it is within 2 beats (step S22: Yes), the underpressurization determining means 20 determines whether or not the pulse characteristic value is below a threshold value (step S23). Here, the characteristic value of the pulse is a peak value, that is, a pulse wave amplitude value. When the pulse wave amplitude value is larger than the threshold value (step S23: No), it is determined that the pressurization is insufficient. Then, the process proceeds to step S <b> 16 in FIG. 6, the pressurization stop pressure is reset, and the cuff 1 is repressurized. When the pulse wave amplitude value is equal to or less than the threshold value (step S23: Yes), it is determined that the cuff pressure is sufficient, and the process proceeds to step S17 in FIG. 6 to perform blood pressure measurement processing.

  Conventionally, if noise larger than the threshold value occurs due to the influence of body movement or the like in the early stage of the decompression process, it is determined that the pressurization is insufficient. Regardless, there was a problem that re-pressurization was performed. On the other hand, according to the embodiment, since the determination of insufficient pressurization is not performed when the certainty of the pressurization stop pressure is very high, such erroneous determination due to the influence of noise is eliminated. Unnecessary repressurization can be avoided. Further, when the certainty of the pressurization stop pressure is high, the threshold value is increased to make it difficult to determine that the pressurization is insufficient, so that the risk of erroneous determination due to noise is reduced. As described above, the present invention is not limited to the above-described embodiment, and various modifications can be made.

  In this embodiment, the pulse wave amplitude value is used as the characteristic value of the pulse used for the determination of insufficient pressurization. However, the present invention is not limited to this, and a pulse wave area or a pulse wave differential value may be used. Of course, the determination may be made by combining and combining the pulse wave amplitude value, the pulse wave area, and the pulse wave differential value. When the pulse wave area is used, a triangular area obtained by connecting the start point, the apex, and the end point of the pulse wave with a straight line may be approximately used.

  As described above, the electronic sphygmomanometer according to the present invention is useful for an electronic sphygmomanometer that measures blood pressure during decompression of the cuff, and in particular, determines the pressurization state of the cuff at the initial stage of the start of decompression of the cuff. Suitable for electronic blood pressure monitors with functions.

It is a block diagram which shows the structure of the electronic blood pressure meter concerning embodiment of this invention. It is a characteristic view which shows the relationship between the cuff pressure in a pressurization process, and its differential value. It is a table | surface which shows an example of the threshold value setting table of the electronic blood pressure monitor concerning embodiment of this invention. It is a characteristic view which shows an example of the relationship between the pressurization stop pressure and threshold value of the electronic blood pressure monitor concerning embodiment of this invention. It is a flowchart which shows the blood-pressure measurement procedure of the electronic sphygmomanometer concerning embodiment of this invention. 6 is a flowchart showing a continuation of FIG. It is a flowchart which shows the insufficient pressurization determination procedure of the electronic blood pressure monitor concerning embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cuff 2 Pressurizing means 4 Depressurizing means 5 Pressure detecting means 11 Pulse wave component detecting means 12 Pulse wave amplitude value calculating means 20 Pressurizing insufficient determining means

Claims (8)

An electronic device comprising: a cuff; a pressurizing unit that pressurizes the cuff; a depressurizing unit that depressurizes the cuff after the pressurization is completed; and an underpressurization determining unit that determines whether or not the cuff pressure is insufficient during the depressurization process of the cuff. In the sphygmomanometer,
An electronic sphygmomanometer, characterized in that the determination by the insufficient pressurization determining means is not performed in accordance with pulse wave information extracted in the pressurizing process of the cuff.   A pressure detecting means for detecting the pressure of the cuff; a pulse wave information detecting means for detecting pulse wave information from a cuff pressure signal detected by the pressure detecting means; and an application for calculating a pressurization stop pressure from the pulse wave information. Pressure stop pressure calculation means, and pressurization stop pressure estimation accuracy calculation means for calculating the accuracy of the pressurization stop pressure from the pulse wave information, and the insufficient pressurization according to the accuracy of the pressurization stop pressure The electronic sphygmomanometer according to claim 1, wherein the determination by the determination unit is not performed. A pulse wave amplitude information calculating unit that detects a pulse wave component superimposed on the cuff pressure signal detected by the pressure detecting unit and calculates pulse wave amplitude information from the detected pulse wave component;
The underpressurization determining means compares the pulse wave amplitude information captured in the cuff depressurization process with a threshold value, and when the pulse wave amplitude information is equal to or less than the threshold value, the cuff pressure is sufficient. 3. The electronic sphygmomanometer according to claim 2, wherein a determination is made and it is determined that the cuff pressure is insufficient when the pulse wave amplitude information is greater than the threshold value. A cuff, a pressurizing unit that pressurizes the cuff, a depressurizing unit that depressurizes the cuff after pressurization, a pressure detecting unit that detects the pressure of the cuff, and a cuff pressure signal detected by the pressure detecting unit. The pulse wave amplitude information calculating means for detecting the superimposed pulse wave component and calculating the pulse wave amplitude information from the detected pulse wave component is compared with the pulse wave amplitude information captured during the cuff decompression process and a threshold value. In an electronic sphygmomanometer comprising an underpressure determination means for determining whether or not the cuff pressure is insufficient,
An electronic sphygmomanometer, wherein the accuracy of pulse wave information is calculated from the cuff pressure signal detected by the pressure detection means, and the threshold value is changed according to the accuracy of the pulse wave information.   From the pulse wave information detecting means for detecting pulse wave information from the cuff pressure signal detected by the pressure detecting means, the pressurization stop pressure calculating means for calculating the pressurization stop pressure from the pulse wave information, and the pulse wave information. 5. A pressurization stop pressure estimation accuracy calculation means for calculating the accuracy of the pressurization stop pressure, and the threshold value is changed according to the accuracy of the pressurization stop pressure. The electronic sphygmomanometer described in 1.   The insufficient pressurization determining means determines that the cuff pressure is sufficient when the pulse wave amplitude information is equal to or less than the threshold value, and the cuff pressure is insufficient when the pulse wave amplitude information is greater than the threshold value. The electronic sphygmomanometer according to claim 4, wherein the electronic sphygmomanometer is determined as follows.   2. The pulse wave information is one or more kinds of information among a pulse wave number extracted during the pressurizing process of the cuff, a pulse wave interval, and a calculated pulse wave amplitude value. The electronic blood pressure monitor as described in any one of thru | or 6.   8. The electron according to claim 1, wherein the pulse wave amplitude information is one or more kinds of information of a pulse wave amplitude value, a pulse wave area, or a pulse wave amplitude differential value. 9. Sphygmomanometer.

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