JP4943869B2 - Blood pressure measurement device - Google Patents

Description

  The present invention relates to a blood pressure measurement device and a blood pressure measurement method, and more particularly to a technique for measuring blood pressure by an oscillometric method using an ischemic cuff.

  The method of obtaining systolic blood pressure in the blood pressure measurement method using an ischemic cuff is to raise the cuff pressure once higher than the systolic blood pressure, which is the highest pressure in the artery, and lower it after the blood flow in the artery is stopped In this case, the blood flow is detected when the blood vessel pressure and the cuff pressure coincide with each other.

  According to the oscillometric sphygmomanometer, the cuff pressure is increased to a pressure higher than the systolic blood pressure, and the arterial vibration generated based on the change in the volume of the artery at the measurement site is detected while gradually decreasing the cuff pressure. The blood pressure was determined by the change in amplitude of vibration.

  On the other hand, according to the Korotkoff method (auscultation method), the cuff pressure is raised above the systolic blood pressure, and once the blood flow is stopped, the cuff pressure is gradually lowered and the blood flow is resumed. The Korotkoff sound is detected at the distal side downstream of the cuff, the internal pressure of the air bag for ischemia at that time is obtained as the systolic blood pressure value (maximum blood pressure value), and the internal pressure of the air bag for ischemia in which the Korotkoff sound has disappeared is expanded It is calculated as the blood pressure value (minimum blood pressure value).

  The oscillometric method is a method of capturing the phenomenon of blood flow resumption as a change in the volume of the artery under the cuff as a pressure vibration of the air bag for ischemia. This eliminates the need for a microphone or a stethoscope for detecting Korotkoff sound, which is necessary in the Korotkoff method, and has the advantage of reducing costs.

  In addition, the Korotkoff sphygmomanometer detects noise (cuff cloth, cuff tube rubbing noise, vibration) generated during blood pressure measurement as the frequency component of the noise is close to the frequency component of the Korotkoff sound. Has the disadvantage of being easily done.

  On the other hand, the frequency component of the pressure fluctuation used in the oscillometric method is considerably lower than the frequency component of the Korotkoff sound, and greatly deviates from the noise frequency generated during blood pressure measurement. For this reason, the oscillometric method is less susceptible to noise, and can be measured sufficiently even when there is some misalignment compared to the Korotkoff method, where positioning of the microphone and artery is important. Therefore, it is suitable for an automatic blood pressure monitor used at home.

  However, the oscillometric method has a problem related to detection of systolic blood pressure (maximum blood pressure value) due to blood vessel compression characteristics. The Ribarochchi cuff, which winds an air bag around a measurement site and pressurizes and depressurizes the air bag to measure the blood pressure, can obtain a compressive force reflecting the cuff pressure at the center in the width direction. However, if it deviates from the central portion, the compression force reflecting the cuff pressure cannot be obtained, and the compression force gradually decreases from the central portion toward the end portion of the cuff, and the end portion exhibits zero characteristics.

  Due to these characteristics, the cuff pressure is increased more than the systolic blood pressure, and the cuff pressure is gradually decreased from the ischemic state to measure the systolic blood pressure. The cuff pressure is slightly higher than the systolic blood pressure. When high, blood flow is stopped only at the center of the cuff. As a result, a phenomenon occurs in which the blood flow enters and returns from the upstream portion of the cuff to the central portion of the cuff in synchronization with the pulsation of the heart. Due to this phenomenon, the generation of a pulse wave that detects the resumption of blood flow downstream of the cuff (forearm side), which is a detection index of systolic blood pressure, has already occurred when the cuff pressure is higher than the systolic blood pressure. There is a problem.

  In addition, when the cuff pressure becomes lower than the systolic blood pressure and the blood flow is resumed, a volume change due to the resumed blood flow occurs downstream from the center part under the cuff. Since the vessel is slightly below the arterial pressure, the blood vessel closes immediately after opening for a short time, so the downstream volume change under the cuff is very small compared to the upstream volume change. Since the pulse wave detected by the oscillometric method is a volume change in which the upstream volume change under the cuff and the downstream volume change overlap, only the pulse wave change based on the resumption of blood flow is selected. It becomes very difficult to detect. As described above, the oscillometric method causes the deterioration of the S / N ratio in the measurement of systolic blood pressure as compared with the Korotkoff method.

  In order to solve the above-described problems in the detection of the resumption of blood flow, the following measures have been conventionally taken.

  When the pressure of the cuff is further lowered from the systolic blood pressure, the volume change on the downstream side under the cuff is gradually increased because the time during which the arterial pressure becomes higher than the cuff pressure becomes longer within one heart cycle. The increase gradually increases the amplitude of the pulse wave. Further, although depending on the degree of congestion, if the intravascular pressure at the peripheral portion of the artery is higher than the cuff pressure, the pressure reflection phenomenon from the periphery occurs, and the pulse wave suddenly increases due to this reflection.

  As the cuff pressure is further reduced, the time during which the vascular pressure in the peripheral region is larger than the cuff in the peripheral region is longer than the cuff pressure, and the upstream region of the cuff is just before the blood vessel is closed within one vibration cycle. A phenomenon occurs in which the blood vessels in the downstream portion are fully opened at the same time and the amplitude of the pulse wave is maximized.

  In the measurement of systolic blood pressure by the oscillometric method, the volume change at this time is the cuff center portion where the volume change under the cuff mainly corresponds to about 50% of the whole blood volume under the cuff. Since this is a change on the upstream side, a method is adopted in which the systolic blood pressure is set at a timing at which the pulse wave amplitude of about 50% of the maximum pulse wave amplitude generated by repeating the fully open and fully closed blood vessels under the cuff repeatedly. is doing.

  However, this ratio indicates that the upstream and downstream volume imbalance contributes to the formation of the pulse wave under the cuff due to the cuff winding, the compliance difference due to the cuffing strength, and the increase in the intravascular pressure at the peripheral site. And affected by the rate of change. In addition, the increase in intravascular pressure at the peripheral site is affected by the degree of congestion due to the short repetition time of blood pressure measurement, but the blood pressure value, the degree of peripheral circulation, the vascular compliance on the peripheral side, which are mainly individual differences in the living body, are affected. Affect.

In order to solve these problems, a double cuff method has been proposed. In this double cuff system, a blood-breaking air bag used for compressing a blood vessel and a pulse-wave detection air bag for detecting only a pulse wave are provided separately from the blood-blocking function at a central portion below the blood-breaking air bag. According to the double cuff method, the influence of the pulse wave based on the volume change on the upstream side under the air bag for ischemia at the time of measuring the systolic blood pressure, which is a problem in the oscillometric method, can be reduced. It is possible to detect a change in volume on the downstream side under the air bag for ischemia as a guideline with a good S / N ratio. (Patent Document 1)
However, at the detection timing of systolic blood pressure, the blood flow that enters the upstream side under the air bag for ischemia enters the immediate vicinity of the air bag for detecting the pulse wave. The vibration due to this invasion is partially transmitted to the pulse wave detection air bag. In addition, since the pulse wave detection air bag is provided below the ischemic air bag, the cuff vibration based on the volume change on the upstream side of the cuff below the ischemic air bag detected by the ischemic air bag is in contact. As a result of partial transmission to the pulse wave detection air bag, the S / N ratio in measurement of systolic blood pressure may be deteriorated.

Therefore, the pressure detection performance of the pulse wave detection air bag is improved so that the blood flow entering from the cuff upstream side to the pulse wave detection air bag is not brought close when the blood vessel is closed with the air bag for ischemia. A backing material is installed between the air bag for pulse wave detection and the air bag for ischemia, and a buffer material for damping the transmitted pulse wave from the air bag for ischemia is installed. There has also been proposed a buffer material for damping the pulse wave. (Patent Document 2)
However, according to this proposal, the compression force of the pulse wave detection bladder can be improved, but there is a large variation in the distance that the position where the pulse wave enters from the upstream part of the cuff is separated from the pulse wave detection bladder. There is a problem. In addition, since the damping characteristics of the member used are limited, a relatively high frequency component of the pulse wave can be attenuated, but a low component cannot be sufficiently attenuated. For this reason, the systolic blood pressure may not be detected with a good S / N ratio.

  Further, in the double cuff method, when both the pressure of the ischemic bladder and the pressure of the pulse wave detecting bladder are detected using one pressure sensor, the cuff upstream generated when the cuff pressure is equal to or higher than the systolic blood pressure. Since the change in blood vessel volume on the side is detected by the air bag for ischemia and transmitted to the pressure sensor via the pipe, it is necessary to attenuate the change in pulse wave in the air bag for ischemia.

Therefore, according to the double cuff method, a fluid resistor is provided between a large capacity buffer tank having a capacity of, for example, 500 cc or more in parallel with the air bag for ischemia, the air bag for ischemia and the air bag for detecting the pulse wave, thereby The pulse wave detected by the air bag for smoothing is attenuated by smoothing.
JP 2004-195056 A Japanese Patent No. 3667326

  Therefore, the present invention has been made in view of the above situation, and in the double cuff sphygmomanometer which is an improved version of the oscillometric method, the cuff upstream side worsens the S / N ratio at the time of systolic blood pressure measurement. A large volume buffer tank that can improve the S / N ratio by attenuating the pulse wave and detecting the pressure of the air bag for the ischemia and the pulse wave of the air bag for detecting the pulse wave using one pressure sensor An object of the present invention is to provide a blood pressure measurement device and a blood pressure measurement method that are configured such that the size can be reduced without using the device.

  In order to solve the above-described problem, according to the blood pressure measurement device of the present invention, a cuff member that is detachably attached to a blood pressure measurement site, and a blood pressure measurement site that is laid on the side of the cuff member that contacts the blood pressure measurement site. An air bag for ischemia that compresses the entire body, a sub-air bag that is laid on the air bag for ischemia and compresses the heart side of the blood pressure measurement site, and a downstream side of the artery for the blood pressure measurement site that is laid on the air bag for ischemia A blood pressure measuring device comprising: a cuff main body configured to include a pulse wave detecting air bag; and a pressure increasing / decreasing means connected via a pipe to pressurize and depressurize the cuff main body, The pipe has a first pipe connected to the air bag for ischemia and the sub air bag, a cuff pressure detection for obtaining a cuff pressure signal from a pressure change of the pulse wave detection air bag and the pulse wave detection air bag. Second arrangement connected between the means And a pulse wave detecting means for detecting a pulse wave superimposed on the cuff pressure signal and obtaining a pulse wave signal, comprising a bypass flow path branched and connected between the first pipe and the second pipe, A blood pressure detection means for determining a blood pressure value based on the cuff pressure signal and the pulse wave signal; and a blood pressure display means for displaying the blood pressure value, the first acoustic resistance, the second acoustic resistance, the acoustic inertance, and the acoustic An acoustic impedance means including compliance is connected to the bypass flow path to attenuate the pressure fluctuation of the heartbeat vibration frequency included in the cuff pressure signal during the decompression.

  In addition, the first acoustic resistance and the first acoustic inertance are obtained by a first coil body that is connected from the first piping side and is wound in a coil shape with a tube body having a first flow path length and a first inner diameter hole. In addition, the second acoustic resistance and the second acoustic inertance are obtained by a second coil body that is connected from the second piping side and is wound in a coil shape with a tubular body having a second flow path length and a second inner diameter hole. In addition, the acoustic impedance means is configured to obtain the acoustic compliance by a volume body having a volume portion connected between the first coil body and the second coil body.

  In addition, a set of vertical portions for accommodating the first inlet end portion and the first outlet end portion of the first coil body and the second inlet end portion and the second outlet end portion of the second coil body in alignment. The first coil body and the second coil body are stacked and stored in a cylindrical body having a groove, and has a connection opening connected to the first outlet end and the second outlet end. It is characterized in that it is directly connected to the volume body.

  Further features of the present invention will become apparent from the best mode for carrying out the present invention and the accompanying drawings.

  According to the present invention, when the cuff pressure is higher than the systolic blood pressure by the sub-cuff provided in the upstream portion on the blood pressure measurement site side of the air bag for ischemia and the acoustic impedance device provided in the bypass flow path branched from the pipe. The pulse wave generated on the upstream side of the cuff can be attenuated, and the pulse wave generated by the blood flow flowing downstream of the cuff, which is a detection index of systolic blood pressure, can be detected with a high S / N ratio. This can be realized and a large buffer tank is not required, and the size can be reduced.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram showing a blood pressure measurement device according to an embodiment of the present invention.

  In the embodiment shown in the figure, the cuff body 1 includes a cloth cuff member 2 that is detachably provided to a blood pressure measurement site including the upper arm portion, and a male cuff indicated by a broken line is provided at the end of the back surface of the cuff member 2. A surface fastener 3 is provided, and a female surface fastener 4 is provided at the end of the surface. The cuff member 2 is wound around the upper arm as shown in the figure, and the hook-and-loop fastener 1 is locked so that the cuff body 1 can be attached and detached. Here, the hook-and-loop fastener is merely an example, and other members may be used, or an arm-in type in which the upper arm is inserted after being formed in a cylindrical shape may be used.

  On the blood pressure measurement site side of the cuff member 2, an air bag 8 for ischemia shown in broken lines is laid to press the entire blood pressure measurement site. In addition, a sub air bag 9 shown in a broken line having a narrower width is laid on the side in contact with the blood pressure measurement site of the ischemic air bladder 8 so as to compress the heart H side of the blood pressure measurement site. The air bag 8 for ischemia and the sub air bag 9 are connected to the first pipe 6 made of a soft tube constituting one pipe connected to the pump 27 and the electromagnetic opening / closing valve 26 which are pressure increasing / decreasing means. As the motor M of the pump 27 is driven, outside air is introduced through the opening 6c to pressurize it, and the air opening / closing valve 26 is energized to exhaust air from the opening 6d so that each air bag can be decompressed. It is configured.

  In addition, the side of the blood pressure measuring part 8 in contact with the blood pressure measuring part presses the blood vessel downstream side of the blood pressure measuring part, and a pulse wave detecting air bag 10 for detecting a pulse wave interposes a blocking device 5 described later. Is laid. The pulse wave detection air bag 10 is connected to a second pipe 7 made of a soft tube to constitute one pipe, and is detachably provided from the main body 20 by the connector 21 together with the first pipe 6. ing. Although it is detachably connected by the connector 21, it may be an integral pipe.

  The bypass pipe 18 is connected to the first pipe 6 and the second pipe 7 from the branch portions 6 a and 7 a, and the pulse wave detection air bag 10 is pressurized and depressurized through the bypass path 18.

  The second pipe 7 includes a change in pulse wave in which a pulse wave component is attenuated by the acoustic filter 22 of the first pipe 6, a change in ischemic pressure in the air bag for ischemia, and a change in pressure in the air bag 10 for detecting the pulse wave. A pressure sensor 30 which is a cuff pressure detecting means for obtaining a cuff pressure signal is connected, a pressure measuring unit 31 for converting the pressure sensor 30 into an analog electric signal is connected, and an A / D converter 32 is further connected. It is connected and configured to output a cuff pressure signal to the central control unit 33 as a digital signal.

  The central control unit 33 includes a ROM, a RAM, and the like that store various computer-readable control programs. The central control unit 33 detects a pulse wave superimposed on the cuff pressure signal and obtains a pulse wave signal and a cuff pressure. A pulse wave processing unit 34, a cuff pressure processing unit 35, a blood pressure measurement unit 37, and a display control unit 38, which are blood pressure detection means for determining a blood pressure value based on a signal (= cuff ischemic pressure), are preinstalled as control programs. .

  Further, the central control unit 33 performs opening / closing drive of the liquid crystal display unit 40 which is a blood pressure display means for displaying a blood pressure value, the pump drive unit 42 which performs drive control of the pump 27, and the electromagnetic opening / closing valve 26. The valve drive control unit 41 is connected, and each operation necessary for blood pressure measurement can be performed in accordance with power supply from the power supply unit 44 including a dry battery.

  On the other hand, the bypass channel 18 is connected with acoustic impedance means 22 shown by a broken line, which is configured by adding a first acoustic resistance, a second acoustic resistance, acoustic inertance, and acoustic compliance, which are formed of thin tubes, as illustrated.

  By connecting to the bypass channel in this way, it occurs due to a change in blood vessel volume on the upstream side of the cuff when the cuff pressure included in the pressure signal of the sub-air bag and the ischemic air bag is higher than the systolic blood pressure at the time of decompression described later. The pressure fluctuation of the subcuff and the air bag for ischemia is attenuated.

  2A is an external perspective view illustrating a state after the cuff body 1 is attached to the upper arm, and FIG. 2B is a cross-sectional view taken along the line YY of FIG. 3 is a cross-sectional view taken along line XX in FIG.

  In FIG. 2 and FIG. 3, the same reference numerals are given to the components or parts already described, and the description will be omitted. First, in FIG. 2A, after the cuff body 1 is attached to the upper arm, the sub air While the bag 9 is positioned on the heart side, the pulse wave detection air bag 10 is positioned on the artery of the measurement site with the blocking device 5 interposed. Moreover, the 1st piping 6 and the 2nd piping 7 will be in the state which has come out outside in parallel like illustration.

  In FIG. 2 (b), the blocking device 5 is provided so as to form an air layer between the blood bag 8 for ischemia and the air bag 10 for pulse wave detection. Transmission to the pulse wave detection air bag 10 is prevented.

  For this reason, the blocking device 5 further refers to the three-dimensional exploded view of FIG. 4, and is formed of a soft sheet material and has a first sheet member 15 having a surface shape of a sealed bag of the pulse wave detection air bag 10, Similarly, the second sheet member 16, the first sheet member 15, and the second sheet member 16, which have the surface shape of the air bag for the pulse wave detection air bag 10, are positioned on the air bag for the ischemic air bag 8. The first spacer members 13 are provided between the short pieces at both ends of the first spacer members 13 and 13 and have the entire length of the short pieces. In addition, a square second spacer member 14 is provided in the center between the first sheet member 15 and the second sheet member 16, and the first sheet member 1 and the second sheet member after attachment are in close contact with each other. By preventing this, an air layer having the same thickness can be maintained as shown in FIG.

  Further, in FIG. 4, the third spacer members 12 and 12 each having the entire length of the short piece of the hermetic bag are further provided on the short pieces at both ends of the hermetic bag, so that the pulse wave detection air bag 10 has a predetermined amount or more. Care is taken to allow air to enter.

  Next, referring to the external perspective view of the air bag 8 for ischemia and the sub air bag 9 shown in FIG. 5 (b), the sub air bag 9 is not limited to the size shown in the drawing, The portion may protrude, and if it is correctly arranged on the heart side, it may have the same vertical length as that of the air bag 8 for ischemia.

  The sub air bag 9 includes a first pipe 6 and a bar member 11 that can be bent as a whole by sandwiching the front and back sheet materials 9a and 9b made of a soft resin from above and below, and then attaching the flange portion 9f to the first pipe 6 (FIG. 5). (see (c)) is prepared as an integrally formed hermetic bag in which the inside is hermetically sealed by continuous heat welding and the communicating portion is formed along the longitudinal direction of the rod member 11. At the same time, the rod member 11 is also sandwiched from the top and bottom sheet materials 8a and 8b made of a soft resin from the top and bottom of the air bag 8 for ischemia, and then the flange portion 8f is continuously welded at a high frequency as shown in the figure so that the inside is sealed. Prepare as a one-piece sealed bag. After that, by folding one of the sealed bags in the direction of the arrow, the bar member 11 is also bent about 180 degrees to obtain the state shown in FIG.

  According to this configuration, the piping individually connected to the ischemic air bag 8 as in the prior art becomes unnecessary, so that the cost can be reduced accordingly, and the sub air bag 9 is first inflated at the time of pressurization, Thereafter, the air bag 8 for ischemia is pressurized and inflated.

  As a result, the tendency that the air supply amount to the sub air bag 9 is reduced can be effectively prevented, and the decrease of the pulse wave attenuation effect by the sub air bag 9 can be prevented. Further, since the amount of air in the sub air bag 9 can be made constant, variations can be prevented. Further, according to the conventional configuration, the residual air amount in the sub air bag 9 may vary depending on the residual air amount of each air bag at the time of pressurization. It can be completely eliminated.

  After the rod member 11 is bent as described above and laid so that the air bags overlap each other, the pulse wave detection air bag 10 to which the second pipe 7 is connected after the state shown in FIG. Be placed. Here, the sub air bag 9 is integrally formed from a first sealing bag formed in a rectangular flat shape using a soft material, and a first pipe 6 whose open end communicates with the first sealing bag. The air bag 8 for ischemia is formed from a second airtight bag formed in a rectangular flat shape larger than the first airtight bag using a soft material, and one end of the bar member 11 is relayed to the first airtight bag. The tube is integrally molded with the other end of the tube positioned in the second sealed bag.

  Further, the pulse wave detection air bag 10 may be integrally formed by continuously joining the flange portion 10f after the second pipe 7 is sandwiched from above and below by the soft material front and back sheet materials 10a and 10b. Needless to say.

  In FIG. 3 again, the cuff is attached so as to be on the left ventricular side where the blood flow of the artery at the blood pressure measurement site flows. Further, as described above, the blocking device 5 is provided so as to form an air layer between the air bag 8 for ischemia and the air bag 10 for detecting the pulse wave. The vibration generated by the volume change is effectively prevented from being transmitted to the pulse wave detection air bag 10.

  Conventionally, a damper having a laminated structure of rigid plate material and foamed urethane is provided in place of the blocking device 5. However, the damping characteristic of this damper may be compressed due to the cuff pressure, and in particular, a damping characteristic that absorbs vibrations close to the heartbeat frequency could not be obtained.

  On the other hand, since the air layer as described above is provided and the air layer can be maintained in a state where the air layer is not crushed, a damping characteristic that absorbs vibration close to the heartbeat frequency can be obtained.

  As a result, when the internal pressure of the air bag 10 for ischemia is slightly lower than the blood pressure, it is possible to detect the pulse wave M generated on the downstream side of the cuff blood vessel with a high S / N ratio. It was.

  Further, the cooperative action with the acoustic impedance means 22 described later prevents the pulse wave generated on the upstream side of the cuff generated when the cuff pressure is higher than the blood pressure from being transmitted between the cuffs. Only the pulse wave change due to the arterial volume change due to the blood flow that is attenuated and pulsates downstream at the measurement timing at the measurement timing can be accurately detected by improving the S / N ratio.

Next, FIG. 6 is a schematic diagram of the acoustic impedance means 22 connected to the bypass flow path 18 described above. In this figure, the same reference numerals are given to the components or parts that have already been described, and the description thereof is omitted. The branch portion 6a of the first pipe 6 has a first flow path length L1 and a first inner diameter hole cross-sectional area S1. is connected first coil member 23 wound in a coil shape is a tube having a together with obtaining a first acoustic resistance from the relation of friction r / S1 ^2, the relationship of the first acoustic inertance L1 * air density / S1 Have gained from.

On the other hand, a second coil body 25 in which a tube having a second flow path length L2 and a second inner diameter hole cross-sectional area S2 is wound in a coil shape is connected to the branch portion 7a of the second pipe 7. with obtaining the resistance from the relation of friction r / S2 ^2, and a second acoustic inertance to obtain the relation of L2 * air density / S2.

An acoustic compliance is obtained from a relational expression of volume W / air density * sound speed ² by a volume body having a volume portion connected between the first coil body 23 and the second coil body 25, so that the overall acoustic impedance is obtained. Means 22 is configured, and the cut-off frequency is the same as or approximated to the heartbeat vibration so as to be attenuated as air vibration. By winding each coil as described above, a volume of about 1/10 of the conventional buffer tank volume can be realized, and the entire apparatus can be downsized.

  FIG. 7 is an external perspective view illustrating one configuration for miniaturization. The first inlet end portion 23a and the first outlet end portion 23b of the first coil body 23 and the second inlet end portion 25a and the second outlet end portion 25b of the second coil body 25 shown in broken lines are aligned vertically. Yes. From this state, a cylindrical body 53 having a pair of longitudinal groove portions 53a and 53b for accommodating each coil body is provided, and the first coil body 23 and the second coil body 25 are laminated inside as shown in the figure. Let me store.

  On the other hand, a fixing portion 52 is formed on the mounting base 52 of the main body so that the cylindrical body 53 can be moved downward and fixed. In addition, a volume body 24 having connection openings 24a and 24b is provided adjacent to the first outlet end portion 23b and the second outlet end portion 25b so that they can be directly connected as shown in the figure. ing. The volume body 24 is also fixed by matching with the fixing portion 51 of the mounting base 52.

  According to the acoustic impedance means 22 having the above configuration, the pulse wave component normally detected by the sub-air bag and the ischemic air bag can be attenuated by 1 to 1.5 Hz, that is, 60 to 70 beats / min. Only the change in the pulse wave due to the change in the volume of the artery on the downstream side of the cuff can be accurately detected by improving the S / N ratio at the measurement timing of the systolic blood pressure.

  The cuff body 1 configured as described above can be used for various blood pressure measuring devices. For example, the blood pressure measuring device shown in FIG. 1 reads the stored control program by a computer, and FIG. The blood pressure measurement routine can be operated as shown in the flowchart of FIG.

  First, the blood pressure measurement device is activated, the cuff body 1 is mounted as shown in FIG. 2, and when a start switch (not shown) is pressed, the valve drive unit 41 energizes the on-off valve 26 in step S1, and the valve The air remaining in each air bag is exhausted by opening the. When the exhaust of the residual air is completed, the pressure sensor is zero-set (initialized), and then the on-off valve 26 is closed in step S2 to prepare for measurement.

  Thereafter, in step S3, the pump 27 is continuously driven with a set pressure P equal to or higher than 20 to 30 mmHg higher than the expected systolic blood pressure. In step S4, whether or not the pressure of the air bag 8 for ischemia and the sub air bag 9 has reached the set pressure P is checked by a signal from the cuff pressure detecting unit, and continues until the set pressure is reached. In S5, the pump drive is stopped. When the pressure of the cuff body 1 reaches the set pressure P, the process proceeds to step S6, and the pressure reduction control unit uses the signal from the cuff pressure detection unit to start the pressure reduction so that the pressure reduction rate becomes 2 to 3 mmHg / sec.

  Following this, in step S7, a cuff pressure is obtained from the cuff pressure detector, and in the next step S8, detection of a pulse wave is started. In step S9, the pulse wave signal detected by the pulse wave detection unit is sent to the storage unit in the blood pressure detection unit, and the cuff pressure and the pulse wave amplitude are stored as a set. In step S10, the fact that the pulse wave amplitude has suddenly increased is compared with, for example, the average value of the amplitude values so far, and a point that has doubled is detected as a systolic blood pressure point. Steps S6 to S10 are repeated until the above systolic blood pressure is detected.

Subsequently, the process proceeds to step S11, the cuff pressure is reduced, and if the phenomenon that the pulse wave amplitude decreases for each heartbeat is further detected by the blood pressure detection unit in step S12, the pulse wave maximum value is equal to or less than the predetermined ratio until now. For example, a pulse wave of 60% or less is detected, and the cuff pressure at that time is determined as the diastolic blood pressure (minimum blood pressure value). When this diastolic blood pressure is determined, the evacuation control unit rapidly evacuates. In step S13, the systolic blood pressure value and the diastolic blood pressure value thus determined are displayed on the blood pressure display unit 40, and the series of blood pressure measurement operations is completed.

  As described above, it is possible to detect the pulse wave generated on the peripheral side when the internal pressure of the air bag for ischemia is lower than the blood pressure without using the fluid resistance, which is a throttle with a large pressure loss, so the measurement time can be shortened. It becomes.

It is a block diagram which shows the blood pressure measuring device of one Embodiment of this invention. (a) is the external appearance perspective view which illustrated the mode after mounting the cuff main body 1 to the upper arm, (b) is the YY arrow directional cross-sectional view of (a). FIG. 3 is a cross-sectional view taken along line XX in FIG. It is a three-dimensional exploded view of the blocking device 5. (a) is an external perspective view of the air bag 8 for ischemia and the sub air bag 9, and (b) is a development view of the air bag 8 for ischemia and the sub air bag 9. 3 is a schematic diagram of acoustic impedance means 22 connected to a bypass flow path 18. FIG. 2 is an external perspective view of acoustic impedance means 22. FIG. It is operation | movement explanatory flowchart of a blood-pressure measurement apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Blood pressure measuring device 2 Cuff member 3, 4 Surface fastener 5 Shut-off device 6 1st piping 7 2nd piping 8 Blood-blocking air bag 9 Sub air bag 10 Pulse wave detection air bag 18 Bypass flow path 20 Main body 22 Acoustic impedance device 23 First coil 25 Second coil 24 Volume H Heart K Artery M Pulse wave

Claims (3)

A cuff member provided detachably with respect to the blood pressure measurement site, an air bag for ischemia laid on the side of the cuff member in contact with the blood pressure measurement site, and compresses the entire blood pressure measurement site, and laid on the air bag for ischemia A cuff body comprising: a sub-air bag that compresses the heart side of the blood pressure measurement site; and a pulse wave detection air bag that is laid in the air bag for ischemia and compresses the downstream side of the artery of the blood pressure measurement site; A blood pressure measuring device comprising pressure increasing / decreasing means connected via a pipe to pressurize and depressurize the main body,
The piping is
A first pipe connected to the air bag for ischemia and the sub air bag;
A second pipe connected between the pulse wave detecting air bag and a cuff pressure detecting means for obtaining a cuff pressure signal from a pressure change of the pulse wave detecting air bag;
A bypass flow path that is branched and connected between the first pipe and the second pipe;
Pulse wave detection means for detecting a pulse wave superimposed on the cuff pressure signal to obtain a pulse wave signal;
Blood pressure detection means for determining a blood pressure value based on the cuff pressure signal and the pulse wave signal;
Blood pressure display means for displaying the blood pressure value,
By connecting the acoustic impedance means including the first acoustic resistance, the second acoustic resistance, the acoustic inertance, and the acoustic compliance to the bypass flow path, the pressure fluctuation of the heartbeat vibration frequency included in the cuff pressure signal at the time of the decompression A blood pressure measuring device characterized by attenuating minutes. The first acoustic resistance and the first acoustic inertance are obtained by a first coil body that is connected from the first pipe side and wound in a coil shape with a tube body having a first flow path length and a first inner diameter hole,
The second acoustic resistance and the second acoustic inertance are obtained by a second coil body that is connected from the second pipe side and wound in a coil shape with a tube body having a second flow path length and a second inner diameter hole,
2. The acoustic impedance means is configured to obtain the acoustic compliance by a volume body having a volume portion connected between the first coil body and the second coil body. The blood pressure measurement device described. A set of longitudinal groove portions for accommodating the first inlet end portion and the first outlet end portion of the first coil body and the second inlet end portion and the second outlet end portion of the second coil body in alignment. The first coil body and the second coil body are stacked and stored in a cylindrical body having
The blood pressure measurement device according to claim 2, wherein the blood pressure measuring device is directly connected to the volume body having a connection opening connected to the first outlet end and the second outlet end.

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