JP5146997B2 - Electronic blood pressure monitor and signal processing method thereof - Google Patents

Description

  The present invention relates to a signal processing technique in blood pressure measurement, and particularly to a signal processing technique in oscillometric blood pressure measurement.

  The method of extracting blood pressure values (systolic blood pressure values, diastolic blood pressure values) in an oscillometric electronic sphygmomanometer is based on the cuff pressure indicating the pressure in the blood vessel of the artery under the cuff (signal indicating the pressure in the cuff), This utilizes the characteristic that a minute change in the pressure in the blood vessel accompanying the blood flow is superimposed as a pulse wave component.

  The method of extracting the blood pressure value based on the pulse wave component superimposed on the cuff pressure in this way is called an oscillometric method.

  In the conventional oscillometric electronic sphygmomanometer, when measuring the blood pressure value, first, the cuff wound around the ischemic region is pressurized to the systolic blood pressure value or higher, and then the cuff pressure is finely adjusted (for example, 2 to 3 mmHg / second). The pressure is reduced to near atmospheric pressure. Then, the pulse wave component superimposed on the cuff pressure in this decompression process is acquired, and the transition of the amplitude value (pulse wave amplitude value) of the acquired pulse wave component (the pulse wave amplitude value that changes in response to the change in the cuff pressure) A systolic blood pressure value and a diastolic blood pressure value are extracted based on the change profile.

  FIG. 1 is a diagram showing how the cuff pressure changes with the pulse wave component superimposed in the process of reducing the cuff pressure. In the figure, the horizontal axis represents the elapsed time in the decompression process, and the vertical axis represents the cuff pressure. As shown in the figure, the cuff pressure decreases in proportion to the passage of time in the decompression process, and the size and shape of the superimposed pulse wave component also change.

  FIG. 2 is a diagram showing how the pulse wave amplitude value of the pulse wave component superimposed on the cuff pressure is correlated with the change of the cuff pressure in the process of reducing the cuff pressure. As can be seen from FIG. 2, the pulse wave amplitude value gradually increases at the beginning in the process of reducing the cuff pressure, and gradually decreases after the time point M at which the maximum pulse wave amplitude value appears. It has.

  Here, a method of extracting systolic blood pressure values and diastolic blood pressure values in a conventional oscillometric electronic blood pressure monitor will be described with reference to FIG.

  In the conventional oscillometric electronic sphygmomanometer, the pulse wave amplitude value that gradually increases in the process of reducing the cuff pressure is obtained by multiplying the maximum pulse wave amplitude value PA by a predetermined ratio α to a threshold TH1 (= The cuff pressure at the time point L exceeding (α × PA) is extracted and used as the systolic blood pressure value.

  Further, a pulse wave amplitude value that decreases after the time point M at which the maximum pulse wave amplitude value appears passes a threshold TH2 (= β × PA) obtained by multiplying the maximum pulse wave amplitude value PA by a predetermined ratio β. The cuff pressure at the time point N when it reaches is extracted and used as the diastolic blood pressure value.

  The systolic blood pressure value and the diastolic blood pressure value extracted from the pulse wave component superimposed on the cuff pressure in this way are set to the threshold values TH1 and TH2, for example, in order to minimize errors in individual measurements. Until now, attempts have been made to set based on statistical means based on data from several hundred people.

  However, in the case of a method of setting a threshold value based on statistical means and extracting a systolic blood pressure value and a diastolic blood pressure value as in a conventional oscillometric electronic blood pressure monitor, the systolic blood pressure value of the measurement subject In addition, the systolic blood pressure value and the diastolic blood pressure value are correctly extracted for the measurement subject whose tendency of the change profile of the pulse wave amplitude value in the vicinity of the diastolic blood pressure value is different from the tendency of the general change profile. There was a problem that I could not.

  The present invention has been made in view of the above problems, and an object thereof is to accurately extract systolic blood pressure values and diastolic blood pressure values in an oscillometric electronic blood pressure monitor.

In order to solve the above-described problems, an electronic blood pressure monitor according to the present invention has the following configuration. That is,
An air bag for ischemia that is laid on the side in contact with the blood pressure measurement site and compresses the entire blood pressure measurement site;
A sub-air bag that is laid on the side of the air bag for blood pressure measurement that is in contact with the blood pressure measurement site and compresses the heart side of the blood vessel of the blood pressure measurement site;
A pulse wave detection air bag for detecting a pulse wave on the side of the blood pressure measurement site, which is laid on the side in contact with the blood pressure measurement site of the ischemic bladder, and slightly downstream of the blood vessel of the blood pressure measurement site;
An electronic sphygmomanometer capable of detecting a cuff pressure in a decompression process, in which a plurality of pulse wave components are superimposed in time series,
For each of the plurality of pulse wave components superimposed on the detected cuff pressure, the first waveform component due to propagation of the intravascular pressure and the volume of the blood vessel part accompanying the pumping of blood flow in the compressed blood vessel part Identification means for identifying at least a second waveform component derived from a minute change in the position of the sub-air bag and a minute change in the position of the pulse wave detection air bag ,
Of the plurality of pulse wave components, the waveform component derived from a minute change in the position of the sub air bag due to the compression of the sub air bag is suppressed, so that the second waveform component is the first wave component. against the emergence of the first waveform component, recognizes the pulse wave component that have appeared with a delay, of the pulse wave component obtained by said recognition, the pulse wave component and the second waveform component first appears is superimposed A first extraction means for extracting the cuff pressure at the time of being performed as a systolic blood pressure value;
Among the plurality of pulse wave component, said that no longer affected by the pressure of the sub air bag, the second waveform component, relative to the appearance of the first waveform component, emerging without delay First, the second waveform component of the recognized pulse wave components appears without delay with respect to the first waveform component. And a second extraction means for extracting the cuff pressure at the time when the pulse wave component is superimposed as a diastolic blood pressure value.

  According to the present invention, a systolic blood pressure value and a diastolic blood pressure value can be accurately extracted in an oscillometric electronic blood pressure monitor.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. The electronic sphygmomanometer described below is characterized in that the systolic blood pressure value and the diastolic blood pressure value are extracted based on the pulse wave component itself rather than the pulse wave amplitude value change profile.

  The electronic sphygmomanometer shown below is based on the premise that a cuff having a triple cuff structure is used instead of a conventional double cuff structure when extracting a systolic blood pressure value and a diastolic blood pressure value based on a pulse wave component. Hereinafter, embodiments of the present invention will be described in detail. Needless to say, the present invention is not limited to the following embodiments.

[First Embodiment]
1. Relationship between cuff pressure and pulse wave component Extraction for accurately extracting systolic blood pressure value and diastolic blood pressure value based on pulse wave component superimposed on cuff pressure detected using cuff with triple cuff structure In describing the method, first, for comparison, a configuration of a cuff having a double cuff structure and a pulse wave component superimposed on a cuff pressure obtained under the configuration of the cuff will be described.

1.1 Case of Double Cuff Structure (1) Configuration of Cuff of Double Cuff Structure FIG. 3A is a cross-sectional view in the longitudinal direction of the arm (the direction in which the upper arm extends) when the cuff is put on the upper arm 301.

  The cuff shown in FIG. 3A has a double cuff structure including a large cuff 311 for blood vessel ischemia and a small cuff 312 for pressure detection. FIG. 3A shows a state where the blood vessel 300 is blocked at a portion Q by the pressurized large cuff 311 for blood vessel ischemia, and the blood flow from the upstream side 300a to the downstream side 300b is suppressed.

  The force for squeezing the upper arm 301 by the large cuff 311 for blood vessel ischemia is strongest at the center in the width direction in the cuff (portion A in the figure), becomes weaker as it approaches both ends, and becomes almost zero at both ends. The small cuff 312 for pressure detection is provided in the central portion (portion A in the figure) in the width direction in the cuff, and captures a change in intravascular pressure in this portion. The “cuff pressure” described in the specification of the present application means the pressure inside the cuff, but is substantially equal to the compression force of the arm at the central portion (A portion in the figure) in the width direction inside the cuff. .

  Under such a configuration, the pulse wave component superimposed on the cuff pressure detected by the pressure detecting small cuff 312 is the pressure of the cuff generated when the intra-arterial pressure vibrates the blood vessel and propagates to the cuff. The internal volume of the cuff is changed by the waveform component (hereinafter referred to as the W0 waveform) derived from the minute change of the blood vessel, and the internal volume of the blood vessel changes minutely as the blood flow from the upstream side to the downstream side in the cuff. A waveform component (hereinafter referred to as a W1 waveform) derived from a minute change in the cuff pressure caused by the minute change and a waveform component derived from a minute change in the cuff pressure due to reflection from a blood vessel on the outer downstream side of the cuff ( Hereinafter, it is divided into W2 waveform).

Among these, the W1 waveform can be divided into the following three for convenience.
-The inner volume of the blood vessel slightly changes with the pulsation of the blood flow under the central portion in the width direction in the cuff, that is, the portion A in FIG. 3 (hereinafter simply referred to as the central portion A in the cuff). The waveform component W1-A (hereinafter referred to as the W1-A waveform) derived from the minute change in the cuff pressure caused by the minute change in the internal volume of the cuff.
-The internal volume of the blood vessel slightly changes as the blood flows under the upstream portion in the width direction in the cuff, that is, the portion B in FIG. 3 (hereinafter simply referred to as the upstream portion B in the cuff). The waveform component W1-B (hereinafter referred to as the W1-B waveform) derived from the minute change in the cuff pressure caused by the minute change in the internal volume of the cuff.
-The internal volume of the blood vessel changes minutely as the blood flows under the width direction in the cuff, that is, the portion C in FIG. 3 (hereinafter simply referred to as the cuff in the cuff). The waveform component W1-C (hereinafter referred to as the W1-C waveform) derived from the minute change in the cuff pressure caused by the minute change in the internal volume of the cuff.

(2) Properties of Each Waveform Constructing Pulse Wave Component Next, the waveform of the pulse wave component superimposed on the cuff pressure under the configuration of FIG. 3A will be described. FIG. 3B schematically shows a state where the W1 waveform is synthesized from the W1-B waveform, the W1-A waveform, and the W1-C waveform, and is further synthesized with the W0 waveform and the W2 waveform, thereby forming a pulse wave component waveform PW. FIG. The waveform PW of the pulse wave component in FIG. 3B shows a typical waveform of the pulse wave component that appears until the cuff pressure shifts from the systolic blood pressure value to the diastolic blood pressure value in the decompression process.

  The W0 waveform is a waveform component derived from a minute change in the cuff pressure caused by the intra-arterial pressure vibrating the blood vessel and propagating to the cuff, and thus a signal is generated in synchronization with the change in the intra-arterial pressure. Since the W2 waveform is a reflection from the outer downstream part of the cuff with respect to the blood flow, the appearance of the peak is caused by the timing when the pressure in the blood vessel outside the cuff becomes higher than the cuff pressure. Delayed from appearance. FIG. 3B shows that the appearance of the peak of the W2 waveform is delayed from the appearance of the peak of the W1 waveform.

  In general, the reflection of the pulse wave component of the shape of the W2 waveform on the entire waveform is smaller than the reflection of the shape of the W1 waveform (the combined waveform of the W1-B waveform, the W1-A waveform, and the W1-C waveform). Further, when the cuff pressure in the decompression process is close to the diastolic blood pressure value, the pressure in the blood vessel under the downstream portion C in the cuff has sufficiently recovered to the state before ischemia by the cuff. There is virtually no reflection from the blood vessels. Therefore, the waveform component superimposed on the cuff pressure detected in the vicinity of the diastolic blood pressure value has substantially disappeared W2.

  During the depressurization process, during the transition of the cuff pressure from the systolic blood pressure value to the diastolic blood pressure value, blood flows into the central part A of the cuff, and a phenomenon in which blood flows from the upstream side to the downstream side in the cuff is generated. Seen. Therefore, the W1 waveform is superimposed while the cuff pressure shifts from the systolic blood pressure value to the diastolic blood pressure value.

  The blood flow is generated when the cuff pressure is lower than the intra-arterial pressure because the force of blood flow needs to be greater than the force of compressing the blood vessel. The compression force of the upstream part B in the cuff is smaller than the compression force of the central part A in the cuff (this phenomenon is generally called a cuff edge effect). Therefore, the time during which the compression force at the point in the cuff upstream portion B is smaller than the arterial pressure is earlier than the time during which the compression force at the point in the cuff upstream portion A is smaller than the arterial pressure. Therefore, the waveform change of the W1-B waveform appears before the waveform change of the W1-A waveform.

  On the other hand, the W1-C waveform is associated with the pulsation of blood flow under the cuff in the downstream part C. Since the compression force in the cuff inner downstream portion C is lower than the cuff inner central portion A, the compression force in the cuff inner downstream portion C is lower than the arterial inner pressure. However, when no blood flow is generated in the cuff central portion A on the upstream side, naturally no blood flow is generated in the downstream portion C in the cuff. Therefore, the occurrence of blood flow in the cuff inner downstream portion C is substantially equal to the timing at which blood flow occurs in the cuff central portion A. Therefore, the waveform change of the W1-C waveform appears almost simultaneously with the waveform change of the W1-A waveform.

  Here, since the small cuff for pressure detection is attached to the central portion A in the cuff, the W1-A waveform is most easily detected as compared with the W1-B waveform and the W1-C waveform. Therefore, the characteristics of the W1-A waveform are largely reflected in the shape of the W1 waveform as compared with the characteristics of the W1-B waveform and the W1-C waveform.

  Further, the compression force of the upstream portion B in the cuff decreases rapidly as it goes to the end portion of the cuff. Accordingly, even in the upstream portion B within the cuff, the compression force is greatly different between the most upstream side and the central portion A side within the cuff, and therefore the time difference during which the compression force is smaller than the intra-arterial pressure also increases. Accordingly, the width of the change in the W1-B waveform is increased.

  In summary, the W1-B waveform is generated before the W1-A waveform in time, the amplitude of the waveform is smaller than that of the W1-A waveform, and the changing time width is gentle.

  The W1 waveform is generated by the blood flow. Since the generation of blood flow occurs only when the compression force falls below the intra-arterial pressure, the change in the W1 waveform should start with a predetermined time delay, that is, with a predetermined time difference T from the time when the change in the intra-arterial pressure starts. However, because the cuff edge effect causes the compression force to fall below the intra-arterial pressure at the end of the cuff at almost the same timing as the start of the change in the intra-arterial pressure, the change in the W1 component gradually increases with the start of the change in the intra-arterial pressure. The shape becomes larger. That is, conventionally, because of the change component of the W1-B waveform, the change start point of the W0 waveform cannot be clearly distinguished from the change start point of the W1 waveform.

1.2 Triple Cuff Structure Next, the cuff structure of the triple cuff structure and the pulse wave component superimposed on the cuff pressure acquired under the cuff structure will be described.

(1) Configuration of Cuff with Triple Cuff Structure The cuff shown in FIG. 4A has a signal and vibration due to blood flow in the upstream side of the large cuff in addition to the large cuff 411 for blood vessel ischemia and the small cuff 412 for pressure detection. It has a triple cuff structure including a sub-cuff 413 for restraining. FIG. 4A shows a state in which the blood vessel 400 is blocked at the portion Q ′ by the pressurized large cuff 411 for blood vessel ischemia, and the blood flow from the upstream side 400a to the downstream side 400b is suppressed. .

(2) Properties of Each Waveform Constructing Pulse Wave Component Next, the waveform of the pulse wave component superimposed on the cuff pressure under the configuration of FIG. 4A will be described. As described above, in the case of the triple cuff structure, the blood vessel 400 is blocked at the portion Q ′ by the pressurized large cuff 411 and the sub-cuff 413, and the blood flow is suppressed.

  For this reason, the pulse wave component superimposed on the cuff pressure detected by the small cuff 412 for pressure detection suppresses the W1-B component, as shown in FIG. 4B.

  As described above, when the cuff having the triple cuff structure is used, the effect of the sub-cuff 413 makes it possible to remove the W1-B waveform component in the upstream portion in the cuff, and therefore, the W0 waveform and the W1 waveform change in the arterial pressure. It is superimposed with a delay of a time difference T from the start until the intra-arterial pressure exceeds the cuff pressure. As a result, the change start point of the W1 waveform can be clearly identified.

1.3 Change in pulse wave component accompanying change in cuff pressure FIG. 5 shows the cuff pressure in which the pulse wave component is superimposed in the depressurization process after pressurizing to a value higher than the systolic blood pressure value under the triple cuff structure. It is a graph which shows an example of a change of. For convenience of explanation, the pulse wave component is illustrated in an enlarged manner so that the waveform of the pulse wave component can be understood.

  Further, the lower side (511 to 514) of FIG. 5 is a diagram schematically showing the state of blood vessels when each pulse wave component is detected.

  According to FIG. 5, when the first pulse wave component 501 is detected in the depressurization process after pressurizing the systolic blood pressure or higher, the blood is completely blocked under the central part A in the cuff (511 ), The components of the W1-A waveform and the W1-C waveform do not exist. Further, the W1-B waveform component is also substantially absent because it is attenuated by the triple cuff structure. Therefore, only the W0 waveform is detected as the cuff pressure.

  On the other hand, when the second pulse wave component 502 is detected in the decompression process, the maximum value of the arterial pressure is higher than the cuff pressure under the central part A in the cuff. (512). Therefore, in the detected pulse wave component 502, in addition to the W0 waveform, a component W1-A waveform and a W1-C waveform due to blood flow are detected. At this time, the time difference T from the detection of the W0 waveform to the detection of the W1-A waveform and the W1-C waveform is t1.

  It should be noted that the cuff pressure at the time when this state (the state where blood has started to flow) 512 becomes an accurate value of the maximum blood pressure to be obtained.

  Subsequently, when the pulse wave component 503 is detected for the third time in the depressurization process, the change in the arterial pressure becomes larger than the cuff internal pressure under the central part A in the cuff as in the case of detecting the pulse wave component 502. The blood flow occurs at a certain time, and the W1-A waveform and the W1-C waveform are generated in addition to the W0 waveform. However, since the cuff internal pressure is reduced compared to the case where the second pulse wave component 502 is detected, the time from the start of the change in the arterial pressure until the change in the arterial pressure becomes larger than the cuff internal pressure is shortened. Yes. Therefore, when the time difference T from the detection of the W0 waveform to the detection of the W1-A waveform and the W1-C waveform is t2, t2 <t1.

  When the fourth pulse wave component 504 is detected in the decompression process, the cuff pressure and the minimum value of the arterial pressure are substantially the same under the central portion A in the cuff. It becomes a state that disappears. At this time, the time during which the arterial pressure is greater than the cuff pressure is substantially equal to the change start point of the arterial pressure, so the appearance timing of the W0 waveform coincides with the appearance timing of the W1-A waveform and the W1-C waveform, and the time difference T Does not occur.

  It can be said that the cuff pressure at the time when this state (the state where the blood vessel has completely returned to 514) is obtained is an accurate value of the diastolic blood pressure value to be obtained.

2. Extraction principle of systolic blood pressure value and diastolic blood pressure value Considering the above relationship between the state of the blood vessel and the waveform of the pulse wave component, the oscillometric electronic sphygmomanometer accurately calculates the systolic blood pressure value and the diastolic blood pressure value. The logic for extraction is as follows.
(1) Systolic blood pressure value In addition to the W0 waveform, the W1-A waveform and the W1-C waveform are included in each pulse wave component detected in the decompression process after the cuff pressure is increased to the systolic blood pressure value or more. The cuff pressure at the time when the first appearing pulse wave component (pulse wave component 502 in the example of FIG. 5) is superimposed is extracted as the systolic blood pressure value.

In addition, it is possible to extract by following the pressure reduction process shown in FIG. That is, the W1-A waveform and the W1-C waveform that appeared in addition to the W0 waveform disappeared among the pulse wave components detected in the pressurization process after the cuff pressure was reduced below the diastolic blood pressure value. The cuff pressure at the time when the first pulse wave component is superimposed may be extracted as the systolic blood pressure value.
(2) Diastolic blood pressure value Of each pulse wave component detected in the decompression process after the cuff pressure is increased to the systolic blood pressure value or more, the appearance timing of the W0 waveform, the W1-A waveform, and the W1-C waveform The cuff pressure at the time of superimposing the first pulse wave component (in the example of FIG. 5, the pulse wave component 504) that coincides with the appearance timing of is extracted as a diastolic blood pressure value.

  In addition, it is possible to extract by following the pressure reduction process shown in FIG. That is, among the pulse wave components detected in the pressurization process after reducing the cuff pressure below the diastolic blood pressure value, the appearance timing of the W0 waveform and the appearance timing of the W1-A waveform and the W1-C waveform are The cuff pressure at the time when the last pulse wave component that coincides (when there is no delay) is superimposed may be extracted as the diastolic blood pressure value.

3. Functional configuration of electronic sphygmomanometer FIG. 6 is a block diagram showing an electronic sphygmomanometer using a triple cuff according to an embodiment of the present invention to which the above extraction principle is applied.

  In FIG. 6, the cuff body 601 includes a cloth cuff member 602 that is detachably provided to a blood pressure measurement site including the upper arm. The cuff body 601 is provided with a male (hook type) surface fastener 603 and a female (loop type) surface fastener 604 at the end of the cuff member 602 on the measurement site contact side.

  For this reason, the cuff main body 601 can be attached to the upper arm by winding the cuff member 602 around the upper arm as shown in the drawing and locking each hook-and-loop fastener. Here, the hook-and-loop fastener is merely an example, and other members may be used. Alternatively, the hook-and-loop fastener may be formed in a cylindrical shape and inserted into the upper arm.

  Inside the cuff member 602, an ischemic air bag 608 is provided for compressing the whole blood pressure measurement site. In addition, a sub-air bag 607 formed with a narrower width to squeeze the heart H side of the blood pressure measurement site is laid on the side of the air bag 608 that contacts the blood pressure measurement site. A first buffer member 609 that attenuates vibration of the sub air bag 607 is provided between the sub air bag 607 and the ischemic air bag 608.

  In addition, it is laid on the side where the blood pressure measurement site contacts the air bag 608 for ischemia, compresses the blood vessel at the blood pressure measurement site, and changes the internal volume of the blood vessel with the blood flow, so that the cuff Pressure detection air bag 606 for detecting the pressure in the blood vessel including the minute change in the cuff pressure caused by the change in the internal volume, and packing for tightly attaching the pressure detection air bag 606 to the blood pressure measurement site A member 605 is laid.

  In order to pressurize and depressurize the cuff body 601 configured as described above, the pump 623 is connected to the air bag 608 of the cuff body 601 through the second pipe 612 and the pipe 615. Further, the pressure detection air bag 606 of the cuff body 601 is connected to the cuff body 601 via the first pipe 611 and the fluid resistor 614. In addition, the cuff body 601 is connected to the sub air bag 607 via the third pipe 613 and the on-off valve 616.

  A pressure sensor (cuff pressure detection means) 631 for detecting the cuff pressure of the pressure detection air bladder 606 is connected to the pressure detection air bladder 606 via the first pipe 611.

  The first pipe 611, the second pipe 612, and the third pipe 613 are made of soft tubes and are detachably arranged with respect to the main body 630 via the connector 610.

  Note that a damper device 618 (shown by a broken line) having a function of smoothing the pressure by increasing the volume in proportion to the pressure may be connected to the third pipe 613.

  A pump 623 and a rapid exhaust valve / constant speed exhaust valve 622 are connected to the cross branch portion 620. The quick exhaust / constant exhaust valve 622 is connected to the control unit 648, and the on-off valve 616 is connected to the control unit 646. The opening area of the quick exhaust / constant speed exhaust valve 622 is controlled by a command from the central control unit 635, and the opening / closing operation of the on-off valve 616 is controlled by a command from the central control unit 635.

  The pump 623 is driven in accordance with power supply from a pump drive unit 649 connected to the motor M, and pressurizes by introducing outside air into the pump 623 through the opening 623a. The pressurized air is sent to the pipe 615 and the third pipe 613 via the cross-branching portion 620 to pressurize the air bags (605, 607, 608).

  The rapid exhaust valve / constant exhaust valve 622 is configured to vary the opening area with the strength of electromagnetic force in order to realize a pressure reduction speed of 2 to 4 mmHg per second. The rapid exhaust valve / constant speed exhaust valve 622 can set an arbitrary pressure reduction speed based on the PWM drive signal from the control unit 648.

  On the other hand, the cuff pressure detected by the pressure sensor 631 is amplified by the amplifier 632, converted into a digital signal by the A / D converter 633, input to the central control unit 635, and contracted by the central control unit 635. The systolic blood pressure value and the diastolic blood pressure value are extracted. The extracted systolic blood pressure value and diastolic blood pressure value are displayed on the display unit 637.

  Note that the cuff pressure detected by the pressure sensor 631 may be filtered using a high-pass filter. This is because only the pulse wave component can be extracted from the cuff pressure on which the pulse wave component is superimposed by performing the filtering process.

4). Measurement process flow diagram 7 systolic blood pressure value and diastolic blood pressure values, using an electronic sphygmomanometer according to this embodiment (FIG. 6), in measuring the systolic blood pressure value and diastolic blood pressure value, the It is a figure which shows the flow of operation | movement of an electronic blood pressure monitor. In performing the measurement, first, the cuff body 601 is attached to the upper arm as shown in FIG.

  When the start of measurement is instructed, in step S701, the opening area of the quick exhaust valve / constant speed exhaust valve 622 is fully opened, and the open / close valve 616 is opened to exhaust the air bags (605, 607, 608). I do. When exhaust of the residual air in each air bag is completed, the pressure sensor 631 is zero-set (initialized).

  Next, in step S702, the rapid exhaust valve / constant speed exhaust valve 622 is fully closed while the on-off valve 616 is kept open.

  When the preparation for pressurization to the cuff (the air bag for ischemia, the pressure detection air bag, the sub air bag) is completed by the above processing, the pump 623 is driven in step S703.

  Subsequently, in step S704, it is checked whether or not the cuff pressure has reached a specified pressure (a pressure that does not become an obstacle to ischemia and inflates the sub air bag 607 so as to reduce the cuff edge effect). If it is determined in step S704 that the specified pressure has been reached, the process proceeds to step S705, where the on-off valve 616 is closed.

  And the drive of the pump 623 is continued and the cuff pressure is pressurized to a pressurization set value 20-30 mmHg higher than the expected systolic blood pressure.

  In step S706, it is determined whether or not the cuff pressure has reached the pressurization set value. If it is determined that the cuff pressure has reached the pressurization set value, the process proceeds to step S707, and after stopping the pump drive, the cuff decompression routine (step The process proceeds to S708).

5. Flow cuff decompression routine Figure 8 is a diagram showing the flow of a detailed process of the cuff pressure reducing routine (step S 708).

  In step S801, based on the signal from the pressure sensor 631, the control of the opening area of the quick exhaust / constant exhaust valve 622 is started so that the decompression speed becomes 2 to 3 mmHg / sec. In step S802, input of the cuff pressure detected by the pressure sensor 631 is started.

  In step S803, whether or not the W1-A waveform and the W1-C waveform appear in each pulse wave component superimposed on the input cuff pressure is sequentially determined by pulse wave pattern recognition. If it is determined in step S803 that the W1-A waveform and the W1-C waveform have appeared, the process proceeds to step S804, where the first pulse wave component in which the W1-A waveform and the W1-C waveform have appeared is displayed. The cuff pressure (at the time when is superimposed) is extracted as the systolic blood pressure value.

  Further, in step S805, for each pulse wave component superimposed on the input cuff pressure, a time difference T between the appearance timing of the W1-A waveform and the W1-C waveform with respect to the appearance timing of the W0 waveform is sequentially calculated. It is determined whether or not it is zero.

  If it is determined in step S805 that the time difference T = 0, the process proceeds to step S806, and the first pulse that appears at that time (the W1-A waveform and the W1-C waveform appear without delay from the appearance of the W0 waveform). The cuff pressure at the time when the wave component is superimposed is extracted as the diastolic blood pressure value.

  Thereafter, in step S807, the opening area of the quick exhaust valve / constant speed exhaust valve 622 is fully opened, and the on / off valve 616 is opened to bring the cuff to atmospheric pressure.

  In step S808, the extracted systolic blood pressure value and diastolic blood pressure value are displayed on the display unit 637, and the series of operations ends.

  As is clear from the above description, in the electronic sphygmomanometer according to the present embodiment, attention is paid to each component included in the pulse wave component superimposed on the cuff pressure in the decompression process, and the W1-A waveform and the W1-C waveform are observed. The cuff pressure at the time of appearance was extracted as a systolic blood pressure value. This makes it possible to extract the cuff pressure at the time when blood flow begins to flow in the depressurization process after the cuff pressure is increased to the systolic blood pressure value or more. As a result, it is possible to extract the systolic blood pressure value with higher accuracy than in the case where the conventional statistical means is used.

  Further, in the electronic sphygmomanometer according to the present embodiment, the appearance timing of the W0 waveform and the appearance timing of the W1-A waveform and the W1-C waveform in the decompression process after the cuff pressure is increased to the systolic blood pressure value or more. The cuff pressure when the time difference became zero was set as the diastolic blood pressure value. This makes it possible to extract the cuff pressure at the time when the blood vessel is restored based on the decompression process after the cuff pressure is increased to the systolic blood pressure value or more. As a result, it is possible to measure the diastolic blood pressure value with higher accuracy than in the case where extraction is performed by a conventional statistical means.

  In the above description, the method for determining whether or not the W1-A waveform and the W1-C waveform appear in the pulse wave component superimposed on the cuff pressure is not particularly mentioned, but the W1-A waveform is not mentioned. The determination as to whether or not the W1-C waveform appears is made based on the waveform of the pulse wave component.

  As described with reference to FIG. 4, the inner volume of the cuff changes minutely due to the minute change of the inner volume of the blood vessel with the blood flow under the central part A in the cuff, and the cuff generated accordingly The inner volume of the blood vessel changes minutely with the W1-A waveform derived from the minute change in pressure and the blood flow under the cuff downstream portion C, so that the inner volume of the cuff changes minutely and occurs accordingly. The W1-C waveform derived from the minute change in the cuff pressure is a predetermined time difference from the W0 waveform derived from the minute change in the cuff pressure caused by the intra-arterial pressure vibrating the blood vessel and propagating to the cuff. Appears with T. For this reason, the waveform of the pulse wave component in which the W1-A waveform and the W1-C waveform appear with a time difference T has a notch shape (a shape in which the slope changes greatly from the bottom to the peak of the pulse wave component waveform). Will be included.

  Therefore, in the electronic sphygmomanometer according to the present embodiment, whether or not the W1-A waveform and the W1-C waveform appear based on the presence / absence of the notch shape using the waveform characteristics of the pulse wave component. to decide.

[Second Embodiment]
In the first embodiment, the systolic blood pressure value and the diastolic blood pressure value are extracted based on the cuff pressure detected in the decompression process after the cuff pressure is increased to the systolic blood pressure value or higher. However, the present invention is not limited to this. For example, the systolic blood pressure value and the diastolic blood pressure value may be extracted based on the cuff pressure detected in the pressurization process after the cuff pressure is reduced below the diastolic blood pressure value.

  FIG. 9 is a diagram showing a flow of processing for extracting a systolic blood pressure value and a diastolic blood pressure value in the electronic sphygmomanometer according to the present embodiment.

  In step S901, the opening area of the quick exhaust valve / constant speed exhaust valve 622 is fully opened, and the open / close valve 616 is opened to exhaust each air bag (605, 607, 608). When exhaust of the residual air in each air bag is completed, the pressure sensor 631 is zero-set (initialized).

  Next, in step S902, the quick exhaust valve / constant speed exhaust valve 622 is fully closed while the on-off valve 616 is kept open.

  In step S903, the on-off valve 616 is opened, and in step S904, the pump 623 is driven.

  In step S905, it is checked whether or not the cuff pressure has reached a specified pressure (for example, 40 mmHg). If it is determined in step S905 that the specified pressure has been reached, the process proceeds to step S906, where the on-off valve 616 is closed.

  In step S907, the pump 623 is continuously driven and pressurized at 2 to 3 mmHg / sec. In step S908, input of the cuff pressure detected by the pressure sensor 631 is started and stored in a memory in the central control unit 635.

  In step S909, the pulse wave shape for each pulse wave component superimposed on the input cuff pressure is acquired.

  In step S910, it is determined whether or not the systolic blood pressure value has been extracted based on the acquired pulse wave shape. The systolic blood pressure value is superimposed on the first pulse wave component in which the W1-A waveform and the W1-C waveform disappeared in addition to the W0 waveform among the pulse wave components detected in the pressurization process. The cuff pressure at that time is extracted as the systolic blood pressure value.

  If it is determined in step S910 that the systolic blood pressure value has been extracted, the process proceeds to step S911, and the driving of the pump 623 is stopped. In step S912, the quick exhaust / constant exhaust valve 622 is opened.

  In step S913, a diastolic blood pressure value is extracted based on the cuff pressure stored in the memory in step S908.

  In step S914, the extracted systolic blood pressure value and diastolic blood pressure value are displayed on the display unit 637, and the series of operations ends.

  As is apparent from the above description, the electronic sphygmomanometer according to the present embodiment accurately measures the diastolic blood pressure value and the systolic blood pressure value based on the pulse wave component superimposed on the cuff pressure in the pressurization process. It becomes possible. Further, according to the present embodiment, it is possible to shorten the measurement time as compared with the first embodiment.

It is a figure which shows the mode of the change of the cuff pressure on which the pulse wave component was superimposed in the pressure reduction process of the cuff pressure. It is the figure which showed the change profile of the pulse wave amplitude value of the pulse wave component superimposed on the cuff pressure in association with the change of the cuff pressure in the process of reducing the cuff pressure. It is sectional drawing of the longitudinal direction (direction where an upper arm extends) of an arm when a cuff of a double cuff structure is put on upper arm 301 in order to add cuff pressure. It is the figure which showed typically the waveform PW of the pulse-wave component superimposed on a cuff pressure in the pressure reduction process in the case of the cuff of a double cuff structure. FIG. 6 is a cross-sectional view in the longitudinal direction of the arm (the direction in which the upper arm extends) when a cuff having a triple cuff structure is put on the upper arm 401 in order to apply cuff pressure. In the case of a cuff having a triple cuff structure, it is a diagram schematically showing a waveform PW of a pulse wave component superimposed on the cuff pressure in the decompression process. It is a graph which shows a mode that the pulse-wave component is superimposed on the cuff pressure in the pressure-reduction process at the time of depressurizing cuff pressure at a very low speed after pressurizing more than the systolic blood pressure value. It is a block diagram which shows the electronic blood pressure monitor using the triple cuff concerning one Embodiment of this invention. It is a figure which shows the flow of operation | movement for measuring a systolic blood pressure value and a diastolic blood pressure value in the electronic sphygmomanometer according to the first embodiment of the present invention. It is a figure which shows the flow of the process for extracting the systolic blood pressure value and the diastolic blood pressure value in the electronic sphygmomanometer according to the first embodiment of the present invention. It is a figure which shows the flow of the process for extracting a systolic blood pressure value and a diastolic blood pressure value in the electronic blood pressure monitor concerning the 2nd Embodiment of this invention.

Claims (2)

An air bag for ischemia that is laid on the side in contact with the blood pressure measurement site and compresses the entire blood pressure measurement site;
A sub-air bag that is laid on the side of the air bag for blood pressure measurement that is in contact with the blood pressure measurement site and compresses the heart side of the blood vessel of the blood pressure measurement site;
A pulse wave detection air bag for detecting a pulse wave on the side of the blood pressure measurement site, which is laid on the side in contact with the blood pressure measurement site of the ischemic bladder, and slightly downstream of the blood vessel of the blood pressure measurement site;
An electronic sphygmomanometer capable of detecting a cuff pressure in a decompression process, in which a plurality of pulse wave components are superimposed in time series,
For each of the plurality of pulse wave components superimposed on the detected cuff pressure, the first waveform component due to propagation of the intravascular pressure and the volume of the blood vessel part accompanying the pumping of blood flow in the compressed blood vessel part Identification means for identifying at least a second waveform component derived from a minute change in the position of the sub-air bag and a minute change in the position of the pulse wave detection air bag ,
Of the plurality of pulse wave components, the waveform component derived from a minute change in the position of the sub air bag due to the compression of the sub air bag is suppressed, so that the second waveform component is the first wave component. against the emergence of the first waveform component, recognizes the pulse wave component that have appeared with a delay, of the pulse wave component obtained by said recognition, the pulse wave component and the second waveform component first appears is superimposed A first extraction means for extracting the cuff pressure at the time of being performed as a systolic blood pressure value;
Among the plurality of pulse wave component, said that no longer affected by the pressure of the sub air bag, the second waveform component, relative to the appearance of the first waveform component, emerging without delay First, the second waveform component of the recognized pulse wave components appears without delay with respect to the first waveform component. An electronic sphygmomanometer, comprising: a second extraction unit that extracts the cuff pressure at the time when the pulse wave component is superimposed as a diastolic blood pressure value. An air bag for ischemia that is laid on the side in contact with the blood pressure measurement site and compresses the entire blood pressure measurement site;
A sub-air bag that is laid on the side of the air bag for blood pressure measurement that is in contact with the blood pressure measurement site and compresses the heart side of the blood vessel of the blood pressure measurement site;
A pulse wave detection air bag for detecting a pulse wave on the side of the blood pressure measurement site, which is laid on the side in contact with the blood pressure measurement site of the ischemic bladder, and slightly downstream of the blood vessel of the blood pressure measurement site;
A signal processing method in an electronic sphygmomanometer capable of detecting a cuff pressure in a decompression process in which a plurality of pulse wave components are superimposed in time series,
For each of the plurality of pulse wave components superimposed on the detected cuff pressure, the first waveform component due to propagation of the intravascular pressure and the volume of the blood vessel part accompanying the pumping of blood flow in the compressed blood vessel part An identification step for identifying at least a second waveform component derived from a minute change in the position of the sub-air bag and a minute change in the position of the pulse wave detection air bag ;
Of the plurality of pulse wave components, the waveform component derived from a minute change in the position of the sub air bag due to the compression of the sub air bag is suppressed, so that the second waveform component is the first wave component. against the emergence of the first waveform component, recognizes the pulse wave component that have appeared with a delay, of the pulse wave component obtained by said recognition, the pulse wave component and the second waveform component first appears is superimposed A first extraction step of extracting the cuff pressure at a time point as a systolic blood pressure value;
Among the plurality of pulse wave component, said that no longer affected by the pressure of the sub air bag, the second waveform component, relative to the appearance of the first waveform component, emerging without delay First, the second waveform component of the recognized pulse wave components appears without delay with respect to the first waveform component. And a second extraction step of extracting the cuff pressure at the time when the pulse wave component is superimposed as a diastolic blood pressure value. A signal processing method in an electronic sphygmomanometer, comprising:

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