blood pressure monitor

Abstract

To provide a non-invasive blood pressure monitor that can measure blood pressure while the cuff is being pressurized, while also extending the lifespan of the pressurizing pump. [Solution] The non-invasive blood pressure monitor 1 for measuring blood pressure comprises a cuff 3 wrapped around the area to be measured 2, a pressurizing pump 7 for supplying air to the cuff 3, and an air tank 8 and air filters 10, 11 arranged in the air supply path from the pressurizing pump 7 to the cuff 3. Inside the air tank 8, an air chamber 23 is formed, which is located on the pressurizing pump 7 side of all the air filters 10, 11 in the air supply path from the pressurizing pump 7 to the cuff 3, and the air flowing from the pressurizing pump 7 into the air tank 8 flows into the air chamber 23.

Description

Technical Field

[0001] The present invention relates to a non-invasive sphygmomanometer.

Background Art

[0002] Conventionally, a non-invasive electronic sphygmomanometer including a cuff and a pressure pump for supplying air to the cuff has been known (see, for example, Patent Document 1). The electronic sphygmomanometer described in Patent Document 1 includes air flow control means disposed between the cuff and the pressure pump. The air flow control means includes an air tank and fine tubes disposed on both sides of the air tank. The air inlet of the air tank is connected to the pressure pump via the fine tube and the air tube, and the air outlet of the air tank is connected to the cuff via the fine tube and the air tube. In the electronic sphygmomanometer described in Patent Document 1, due to the action of the air flow control means, fluctuations in the flow rate of the pressure pump do not appear as fluctuations in the cuff pressure, and air pressure vibrations due to the pulsation of the pressure pump do not propagate to the air pressure of the cuff. Therefore, with this electronic sphygmomanometer, it is possible to measure blood pressure when the cuff is pressurized.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the electronic sphygmomanometer described in Patent Document 1, as described above, it is possible to measure blood pressure when the cuff is pressurized. However, in the case of this electronic sphygmomanometer, due to the influence of the fine tube disposed between the air inlet of the air tank and the pressure pump, a large load is likely to be applied to the pressure pump when the cuff is pressurized. Therefore, with this electronic sphygmomanometer, the life of the pressure pump may be shortened. Further, in the electronic sphygmomanometer described in Patent Document 1, the pressurization rate of the cuff cannot be controlled.

[0005] Therefore, the first objective of the present invention is to provide a non-invasive blood pressure monitor that can extend the lifespan of the pressurizing pump, even when it is possible to measure blood pressure while the cuff is pressurized. The second objective of the present invention is to provide a non-invasive blood pressure monitor that can control the pressurizing speed of the cuff. [Means for solving the problem]

[0006] To solve the first problem described above, the blood pressure monitor of the present invention is a non-invasive blood pressure monitor for measuring blood pressure, comprising a cuff wrapped around the site to be measured, a pressurizing pump for supplying air to the cuff, and an air tank and an air filter arranged in the air supply path from the pressurizing pump to the cuff, wherein an air chamber is formed inside the air tank, positioned on the pressurizing pump side of all the air filters in the air supply path from the pressurizing pump to the cuff, and the air flowing from the pressurizing pump into the air tank flows into the air chamber.

[0007] In the blood pressure monitor of the present invention, an air tank and an air filter are arranged in the air supply path from the pressurizing pump to the cuff. Therefore, in the present invention, fluctuations in the flow rate of air supplied from the pressurizing pump to the cuff are less likely to manifest as fluctuations in the pressure inside the cuff. Consequently, in the present invention, it is possible to measure blood pressure when the cuff is pressurized. Furthermore, in the present invention, the air flowing from the pressurizing pump to the air tank flows into an air chamber located on the pressurizing pump side of all the air filters in the air supply path from the pressurizing pump to the cuff, without passing through an air filter. Therefore, in the present invention, a large load is less likely to be placed on the pressurizing pump when pressurizing the cuff via the air tank. Consequently, in the present invention, even though it is possible to measure blood pressure when the cuff is pressurized, the lifespan of the pressurizing pump can be extended.

[0008] Furthermore, in order to solve the second problem described above, the blood pressure monitor of the present invention is a non-invasive blood pressure monitor for measuring blood pressure, comprising: a cuff wrapped around the site to be measured; a pressurizing pump for supplying air to the cuff; an air tank and an air filter arranged in the air supply path from the pressurizing pump to the cuff; a first air pressure sensor for detecting the air pressure inside the air tank; a second air pressure sensor for detecting the air pressure inside the cuff; and a blood pressure monitor control unit having a pump control circuit for controlling the pressurizing pump, wherein an air chamber is formed inside the air tank, arranged on the pressurizing pump side of at least one air filter in the air supply path from the pressurizing pump to the cuff; the first air pressure sensor detects the air pressure in the air chamber; and the blood pressure monitor control unit controls the pressurizing pump based on the detection result of the first air pressure sensor.

[0009] The blood pressure monitor of the present invention is equipped with a first air pressure sensor for detecting the air pressure inside an air tank located in the air supply path from the pressurizing pump to the cuff, and the blood pressure monitor control unit controls the pressurizing pump based on the detection result of the first air pressure sensor. Therefore, the present invention makes it possible to control the pressurizing speed of the cuff. Furthermore, in the present invention, since the first air pressure sensor detects the air pressure in an air chamber located on the pressurizing pump side of at least one air filter in the air supply path from the pressurizing pump to the cuff, the detection result of the first air pressure sensor is less affected by the pulse wave of the measurement site due to the action of the air filter. Therefore, in the present invention, it is possible to control the pressurizing speed of the cuff with high precision based on the detection result of the first air pressure sensor. [Effects of the Invention]

[0010] As described above, the blood pressure monitor of the present invention makes it possible to measure blood pressure while the cuff is being pressurized, while also extending the lifespan of the pressurizing pump. Furthermore, the blood pressure monitor of the present invention makes it possible to control the cuff pressurization speed. [Brief explanation of the drawing]

[0011] [Figure 1]This is a schematic diagram illustrating the configuration of a blood pressure monitor according to an embodiment of the present invention. [Figure 2] Figure 1 is a block diagram illustrating the configuration of the blood pressure monitor shown. [Figure 3] This is a schematic diagram illustrating the configuration of a blood pressure monitor according to another embodiment of the present invention. [Figure 4] Figure 3 is a block diagram illustrating the configuration of the blood pressure monitor shown. [Modes for carrying out the invention]

[0012] Embodiments of the present invention will be described below with reference to the drawings.

[0013] (Blood pressure monitor configuration) Figure 1 is a schematic diagram illustrating the configuration of a blood pressure monitor 1 according to an embodiment of the present invention. Figure 2 is a block diagram illustrating the configuration of the blood pressure monitor 1 shown in Figure 1.

[0014] The blood pressure monitor 1 in this embodiment is a non-invasive blood pressure monitor for measuring the blood pressure of humans or experimental animals. The blood pressure monitor 1 comprises a cuff 3 that is wrapped around the part to be measured 2, such as the arm of the person to be measured, to compress an artery, a Korotkoff sound microphone 4 (hereinafter referred to as "microphone 4") attached to the cuff 3, and a blood pressure monitor body 5 to which the cuff 3 is connected. The blood pressure monitor body 5 comprises a pressure pump 7 for supplying air to the cuff 3, and air tanks 8 and air filters 10, 11 arranged in the air supply path from the pressure pump 7 to the cuff 3. The blood pressure monitor body 5 in this embodiment is equipped with two air filters 10, 11.

[0015] Furthermore, the blood pressure monitor body 5 includes an air pressure sensor 12 for detecting the air pressure inside the air tank 8, an air pressure sensor 13 for detecting the air pressure (internal pressure) inside the cuff 3, an intermediate exhaust valve 14 and a constant-speed exhaust valve 15 for discharging air from inside the air tank 8, a full exhaust valve 16 for discharging air from inside the cuff 3, and a blood pressure monitor control unit 17 for controlling the blood pressure monitor 1. In this embodiment, the air pressure sensor 12 is the first air pressure sensor, and the air pressure sensor 13 is the second air pressure sensor.

[0016] The air tank 8 is formed, for example, in a cylindrical (pipe-like) shape with both ends closed. The air tank 8 is made of, for example, polyvinyl chloride. For example, the total length of the air tank 8 is about 150 mm, the outer diameter of the air tank 8 is about 38 mm, and the wall thickness of the air tank 8 is about 3.5 mm.

[0017] Air filter 10 consists of two silencers 21 and a silencer fixing plate 22 to which the two silencers 21 are fixed. Similarly to air filter 10, air filter 11 consists of two silencers 21 and a silencer fixing plate 22. Air filters 10 and 11 function as air resistors. Air filters 10 and 11 are located inside the air tank 8. The silencer fixing plate 22 is formed in a disc shape and is fixed to the inner circumferential surface of the air tank 8. The silencers 21 are fixed to the silencer fixing plate 22 from both sides.

[0018] The interior of the air tank 8 is partitioned by air filters 10 and 11, and an air chamber 23, an air chamber 24, and a connection chamber 25 are formed inside the air tank 8. In this embodiment, the interior of the air tank 8 is composed of an air chamber 23, an air chamber 24, and a connection chamber 25. The air chamber 23 is formed between one end of the air tank 8 and the air filter 10. The air chamber 24 is formed between the air filter 10 and the air filter 11. The connection chamber 25 is formed between the other end of the air tank 8 and the air filter 11. The connection chamber 25 is narrower than the air chambers 23 and 24.

[0019] A pressure pump 7 is connected to the air chamber 23 via an air tube 26 whose one end is attached to the air inlet of the air tank 8. The air flowing from the pressure pump 7 into the air tank 8 flows into the air chamber 23. A cuff 3 is connected to the connection chamber 25 via an air tube 27 whose one end is connected to the air outlet of the air tank 8. The air flowing out of the air tank 8 flows out of the connection chamber 25. The air inlet and outlet are, for example, pipes made of aluminum alloy. Thus, inside the air tank 8, in the air supply path from the pressure pump 7 to the cuff 3, there are formed an air chamber 23 disposed on the pressure pump 7 side of all the air filters 10 and 11, and an air chamber 24 disposed on the pressure pump 7 side of one air filter 11.

[0020] An air pressure sensor 12 is connected to the air chamber 24 via an air tube 28 whose one end is attached to the air inlet / outlet of the air tank 8. The air inlet / outlet is, for example, a pipe made of aluminum alloy. The air pressure sensor 12 functions to detect the air pressure in the air chamber 24. That is, the air pressure sensor 12 functions to detect the pressure of the air passing through the air filter 10 in the air tank 8. An air pressure sensor 13 is connected to the cuff 3 and the connection chamber 25 via the air tube 27 or the like. As described above, the air pressure sensor 13 functions to detect the internal pressure of the cuff 3. In this embodiment, the detection result of the air pressure sensor 13 is used for blood pressure measurement, and the detection result of the air pressure sensor 12 is not used for blood pressure measurement.

[0021] An intermediate exhaust valve 14 and a constant-speed exhaust valve 15 are connected to the air chamber 24 via the air tube 28. A full exhaust valve 16 is connected to the cuff 3 and the connection chamber 25 via the air tube 27 or the like. The intermediate exhaust valve 14 and the full exhaust valve 16 are on-off valves. As will be described later, the sphygmomanometer 1 can measure blood pressure when the cuff 3 is decompressed. The intermediate exhaust valve 14 and the constant-speed exhaust valve 15 are used when measuring blood pressure during decompression of the cuff 3. The full exhaust valve 16 is used to exhaust air from the inside of the cuff 3 after blood pressure measurement is completed.

[0022] The blood pressure measurement control unit 17 includes a pump control circuit 31 that controls the pressurizing pump 7, an amplifier circuit 32 to which the output signal of the air pressure sensor 12 is input, a pressure wave separation circuit 33 to which the output signal of the air pressure sensor 13 is input, an amplifier circuit 34 connected to the full exhaust valve 16, an amplifier circuit 35 to which the output signal of the microphone 4 is input, a setting and display unit 36 for performing various settings and displays, and a CPU 37 to which these components are electrically connected.

[0023] The blood pressure measurement control unit 17 controls the pressurizing pump 7 based on the detection result of the air pressure sensor 12. Specifically, the blood pressure measurement control unit 17 controls the pressurizing pump 7 based on the detection result of the air pressure sensor 12 when pressurizing the cuff. For example, regardless of the size of the cuff 3, the blood pressure measurement control unit 17 controls the pressurizing pump 7 so that the pressure of the cuff 3 increases at a constant rate. Also, for example, after the start of blood pressure measurement, until the cuff 3 lightly contacts the measurement part 2 (for example, until the pressure of the cuff 3 reaches about 20 to 30 mmHg), the blood pressure measurement control unit 17 rapidly pressurizes the pressure of the cuff 3, and then controls the pressurizing pump 7 so that the pressure of the cuff 3 increases at a constant rate slower than during rapid pressurization.

[0024] The blood pressure measurement control unit 17 stores in advance reference pressurization gradient data for increasing the pressure of the cuff 3 at a constant rate. The blood pressure measurement control unit 17 controls the pressurizing pump 7 based on the detection result of the air pressure sensor 12 and the reference pressurization gradient data so that the pressure of the cuff 3 increases at a constant rate. The pressurization speed of the cuff 3 depends on the heart rate of the person being measured and the experimental animal being targeted, but is usually set to about 2 to 5 mmHg per second.

[0025] In the blood pressure monitor 1, it is possible to measure blood pressure when pressurizing the cuff

[0026] During blood pressure measurement, a pressure fluctuation signal based on the pulse wave superimposed on the pressure of the cuff 3 is output from the pneumatic sensor 13 as a blood pressure detection signal. The pressure wave separation circuit 33 amplifies the blood pressure detection signal output from the pneumatic sensor 13 and separates the amplified blood pressure detection signal into a pressure signal and a pulse wave signal. The CPU 37 identifies the blood pressure based on the pulse wave signal input from the pressure wave separation circuit 33 and displays the identified blood pressure on a predetermined display unit. The pressure signal output from the pressure wave separation circuit 33 is a pressure signal corresponding to the pressure in which the influence of the pulse wave of the unit being measured 2 has been reduced (i.e., a pressure close to the pressure of the cuff 3 itself).

[0027] Furthermore, when measuring blood pressure, Korotkoff sounds (blood flow sounds, hereinafter referred to as "K sounds") output from microphone 4 are used. Specifically, when measuring blood pressure while pressurizing cuff 3, the blood pressure at which the K sounds begin to be emitted after pressurization starts is defined as the diastolic blood pressure, and the blood pressure at which the K sounds stop is defined as the systolic blood pressure. Similarly, when measuring blood pressure while depressurizing cuff 3, the blood pressure at which the K sounds begin to be emitted after depressurization starts is defined as the systolic blood pressure, and the blood pressure at which the K sounds stop is defined as the diastolic blood pressure.

[0028] (Main effects of this form) As explained above, in this embodiment, an air tank 8 and air filters 10 and 11 are arranged in the air supply path from the pressurizing pump 7 to the cuff 3. Therefore, in this embodiment, fluctuations in the airflow rate (or air pressure) supplied from the pressurizing pump 7 to the cuff 3 are attenuated by the air tank 8 and air filters 10 and 11. Consequently, in this embodiment, fluctuations in the airflow rate supplied from the pressurizing pump 7 to the cuff 3 are less likely to appear as fluctuations in the internal pressure of the cuff 3, and as a result, it becomes possible to measure blood pressure when the cuff 3 is pressurized.

[0029] In this configuration, the air flowing from the pressurizing pump 7 to the air tank 8 flows into the air chamber 23, which is located on the pressurizing pump 7 side of all the air filters 10 and 11 in the air supply path from the pressurizing pump 7 to the cuff 3, without passing through the air filters 10 and 11. Therefore, in this configuration, the pressurizing pump 7 is less likely to be subjected to a large load when pressurizing the cuff 3 via the air tank 8. Consequently, in this configuration, even if it is possible to measure blood pressure when pressurizing the cuff 3, the lifespan of the pressurizing pump 7 can be extended.

[0030] In this embodiment, the blood pressure monitor 1 is equipped with an air pressure sensor 12 for detecting the air pressure inside an air tank 8 located in the air supply path from the pressurizing pump 7 to the cuff 3, and the blood pressure monitor control unit 17 controls the pressurizing pump 7 based on the detection result of the air pressure sensor 12. Therefore, in this embodiment, it is possible to control the pressurizing speed of the cuff 3.

[0031] In this configuration, the air pressure sensor 12 detects the air pressure in the air chamber 24 located on the side of the pressure pump 7 closer to the pressure pump 7 than the air filter 11 in the air supply path from the pressure pump 7 to the cuff 3. Therefore, due to the action of the air filter 11, the detection result of the air pressure sensor 12 is less affected by the pulse wave of the unit being measured 2. Furthermore, in this configuration, the air pressure sensor 12 detects the air pressure in the air chamber 24 formed between the air filter 10 and the air filter 11. Therefore, due to the action of the air chamber 23 and the air filter 10, the detection result of the air pressure sensor 12 is less affected by fluctuations in the flow rate of the air supplied from the pressure pump 7. Consequently, in this configuration, it becomes possible to accurately control the pressurization speed of the cuff 3 based on the detection result of the air pressure sensor 12.

[0032] (Example of blood pressure monitor modification) Figure 3 is a schematic diagram illustrating the configuration of a blood pressure monitor 1 according to another embodiment of the present invention. Figure 4 is a block diagram illustrating the configuration of the blood pressure monitor 1 shown in Figure 3.

[0033] In the above-described configuration, as shown in Figures 3 and 4, the blood pressure monitor body 5 does not necessarily have to be equipped with an air pressure sensor 12. In the modified example shown in Figures 3 and 4, the blood pressure monitor body 5 does not have an air filter 10, and the inside of the air tank 8 is composed of one air chamber 40 and a connection chamber 25. In this modified example, the intermediate exhaust valve 14 and the constant-speed exhaust valve 15 are connected to the air chamber 40 via an air tube 27.

[0034] In this modified example, the pressure signal output from the pressure wave separation circuit 33 is input to the pump control circuit 31. The blood pressure monitor control unit 17 controls the pressurizing pump 7 when the cuff 3 is pressurized based on the pressure signal output from the pressure wave separation circuit 33. In this modified example as well, since the pressurizing pump 7 is controlled based on a pressure signal with reduced influence from the pulse wave of the unit being measured 2, it becomes possible to control the pressurizing speed of the cuff 3 with high precision.

[0035] (Other embodiments) In the configuration described above, the blood pressure monitor 1 does not need to be equipped with a microphone 4. In this case, when measuring blood pressure while pressurizing the cuff 3, it is difficult to detect the diastolic blood pressure from the pulse wave signal while the cuff 3 is being pressurized. However, as the pressurization continues, the pulse wave signal becomes larger, and its maximum point becomes the mean blood pressure. The systolic blood pressure is then detected. The diastolic blood pressure is calculated from the systolic blood pressure and the mean blood pressure.

[0036] In the above-described configuration, the air filter 11 may be located outside the air tank 8, and the connection chamber 25 may not be formed inside the air tank 8. In these cases, for example, one end of the air tube 27 is connected to the air filter 11. Also, in the above-described configuration, three or more air filters may be located inside the air tank 8, and three or more air chambers may be formed inside the air tank 8.

[0037] In the configuration described above, the blood pressure monitor body 5 does not necessarily have to be equipped with an air filter 10. In this case, as shown in Figure 3, the inside of the air tank 8 is composed of one air chamber 40 and a connection chamber 25. In this case, the air pressure sensor 12 performs the function of detecting the air pressure in the air chamber 40. Furthermore, in the modified examples shown in Figures 3 and 4, the blood pressure monitor body 5 may be equipped with an air filter 10.

[0038] In the above-described configuration, an air chamber 23 does not necessarily have to be formed inside the air tank 8. In this case, for example, one end of the air tube 26 is connected to the air filter 10. Also, in the above-described configuration, an air filter may be placed in the air supply path from the pressure pump 7 to the air tank 8. In this case, for example, the air filter 10 does not necessarily have to be placed inside the air tank 8.

[0039] In the configuration described above, blood pressure may be measured by the blood pressure monitor 1 only when cuff 3 is pressurized. When measuring blood pressure when cuff 3 is depressurized, it is usually necessary to rapidly pressurize cuff 3 to a constant pressure of about 150 mmHg, which requires a large pressurizing pump 7. However, if blood pressure is measured only when cuff 3 is pressurized, rapid pressurization is not necessary, making it possible to miniaturize the pressurizing pump 7. However, if cuff 3 is large, the pressurization rate of cuff 3 may decrease drastically when pressurizing up to nearly 300 mmHg, so it is necessary to select a pressurizing pump 7 that is suitable for cuff 3. [Explanation of Symbols]

[0040] 1. Blood pressure monitor 2 Part to be measured 3 Cuffs 7. Pressure pump 8 Air Tanks 10, 11 Air filters 12. Air pressure sensor (1st air pressure sensor) 13. Air pressure sensor (second air pressure sensor) 17 Blood pressure monitor control unit 23 Air chambers 24 air chambers 31 Pump control circuit 40 air chambers

Claims

1. In a non-invasive blood pressure monitor for measuring blood pressure, The device comprises a cuff wrapped around the area to be measured, a pressure pump for supplying air to the cuff, and an air tank and an air filter arranged in the air supply path from the pressure pump to the cuff. Inside the air tank, an air chamber is formed which is located on the side of the pressure pump that is closer to the pressure pump than all of the air filters in the air supply path from the pressure pump to the cuff. A blood pressure monitor characterized in that the air flowing from the pressure pump into the air tank flows into the air chamber.

2. In a non-invasive blood pressure monitor for measuring blood pressure, The blood pressure monitor comprises a cuff wrapped around the area to be measured, a pressure pump for supplying air to the cuff, an air tank and an air filter arranged in the air supply path from the pressure pump to the cuff, a first air pressure sensor for detecting the air pressure inside the air tank, a second air pressure sensor for detecting the air pressure inside the cuff, and a blood pressure monitor control unit having a pump control circuit for controlling the pressure pump. Inside the air tank, an air chamber is formed which is located on the side of the pressure pump that is closer to the pressure pump than at least one air filter in the air supply path from the pressure pump to the cuff. The first air pressure sensor detects the air pressure in the air chamber, The blood pressure monitor control unit is characterized by controlling the pressurizing pump based on the detection result of the first air pressure sensor.

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