A blood pressure sensor

Abstract

This application provides a blood pressure sensor, comprising: a tubing having a first end and a second end disposed opposite to each other, the first end being for connecting to a blood vessel, and the second end being for injecting a pressure measuring medium; a pressure sensor disposed in the tubing and used for measuring the liquid pressure in the tubing; and a filter element installed at the first end, or installed between the first end and the pressure sensor. The filter element is used to filter blood cells in the blood entering the tubing from the first end, while allowing the pressure measuring medium to pass through. In this application, the filter element prevents large particles such as blood cells from entering the tubing, preventing blood cells from agglomerating and forming thrombi in the tubing, and also preventing blood from being flushed back into the blood vessel, causing a series of serious consequences such as arterial embolism, myocardial infarction, and pulmonary embolism. Simultaneously, the filter element allows the pressure measuring medium to pass through, thereby ensuring smooth pressure measurement.

Description

Technical Field

[0001] This application belongs to the field of blood pressure detection technology, and more specifically, relates to a blood pressure sensor. Background Technology

[0002] Blood pressure sensors are used clinically to continuously measure a patient's arterial blood pressure during each cardiac cycle, reflecting trends and instantaneous changes in blood pressure. The blood pressure sensor connects to a device already inserted into the artery (such as a central venous catheter or indwelling arterial needle). The pressure within the blood vessel is transmitted to the external blood pressure sensor via fluid within the catheter to achieve blood pressure detection. Due to the rapid pumping speed and high pressure of blood in the arteries, blood may potentially enter the transmission tubing of the blood pressure sensor along the catheter within the blood vessel. However, because the fluid flow rate inside the blood pressure sensor is relatively low (approximately 1-3 mL / h), it is difficult to flush the blood that has entered the transmission tubing back into the blood vessel. Furthermore, blood already in the transmission tubing may coagulate into thrombi, and flushing it back into the blood vessel can cause a series of serious consequences such as arterial embolism, myocardial infarction, and pulmonary embolism. Utility Model Content

[0003] The purpose of this application is to provide a blood pressure sensor to solve the technical problem in the prior art where blood from inside blood vessels can easily enter the blood sensor, causing thrombosis and other problems.

[0004] To achieve the above objectives, the technical solution adopted in this application is: to provide a blood pressure sensor, comprising:

[0005] The tubing has a first end and a second end that are arranged opposite to each other. The first end is used to connect to a blood vessel, and the second end is used to inject a pressure measuring medium.

[0006] A pressure sensor is installed in the pipeline and is used to measure the liquid pressure in the pipeline;

[0007] A filter element is installed at the first end, or between the first end and the pressure sensor; the filter element is used to filter blood cells in the blood entering the pipeline from the first end, and the filter element allows the pressure measuring medium to pass through.

[0008] In some embodiments, a connector is provided at the first end of the pipeline, and the filter element is installed in the connector; or, the filter element is installed in the pipeline near the connector.

[0009] In some embodiments, the filter element includes a filter membrane, which has a porous structure.

[0010] In some embodiments, a connector is provided at the first end of the pipeline, the connector having a fluid channel communicating with the pipeline; the filter element includes a filter membrane installed in the fluid channel.

[0011] In some embodiments, the filter membrane has through-pores with a pore size ranging from 0.01µm to 0.1µm.

[0012] In some embodiments, the porosity of the filter membrane ranges from 85% to 95%.

[0013] In some embodiments, at least one surface of the filter membrane is coated with a functional coating that has hydrophilic and / or anticoagulant functions.

[0014] In some embodiments, the functional coating includes a heparin-chitosan coating.

[0015] In some embodiments, the filter membrane includes a filter portion and an edge portion connected to a periphery of the filter portion, the edge portion being used for connection with the connector, and the thickness of the filter portion is in the range of 0.05um-2um.

[0016] In some embodiments, the filter membrane is perpendicular to the length extension direction of the fluid channel.

[0017] The beneficial effects of the blood pressure sensor provided in this application are as follows: By installing a filter at the first end of the tubing or between the first end and the pressure sensor, the filter filters blood cells from the blood entering the tubing from the first end, while allowing the pressure measuring medium to pass through. This arrangement prevents large particles such as blood cells from entering the tubing, thus preventing blood cells from agglomerating and forming thrombi. It also prevents blood from being flushed back into the blood vessels, which could cause serious consequences such as arterial embolism, myocardial infarction, and pulmonary embolism. Simultaneously, the filter allows the pressure measuring medium to pass through, ensuring smooth pressure measurement. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of the blood pressure sensor provided in the embodiments of this application;

[0020] Figure 2 This is a schematic diagram of the structure of the protective film in the blood pressure sensor provided in the embodiments of this application;

[0021] Figure 3 This is an assembly diagram of the filter and connector in the blood pressure sensor provided in the embodiments of this application.

[0022] The following are the labeling elements in the figure:

[0023] 100. Piping; 110. First end; 120. Second end; 200. Pressure sensor; 210. Sensor unit; 220. Housing; 300. Filter element; 310. Filter membrane; 311. Filter section; 312. Edge section; 320. Functional coating; 400. Connector; 410. Annular groove; 420. Fluid passage; 500. Injector; 600. Flow regulator; 700. Terminal; 800. Three-way valve; 900. Protective cap. Detailed Implementation

[0024] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0025] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0026] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0027] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0028] Generally, blood pressure sensors are directly connected to an intravascular catheter. Due to the high pumping speed and pressure of blood in arteries, blood may flow along the intravascular catheter into the blood pressure sensor's delivery tubing. However, because the fluid flow rate inside the blood pressure sensor is relatively low (approximately 1-3 mL / h), it is not easy to flush the blood that has entered the delivery tubing back into the blood vessel. Furthermore, blood that has already entered the delivery tubing may coagulate into thrombi, and flushing it back into the blood vessel could cause a series of serious consequences such as arterial embolism, myocardial infarction, and pulmonary embolism.

[0029] To address the aforementioned technical problems, this application provides a blood pressure sensor. By incorporating a filter 300 in the blood pressure sensor's conduit 100, the filter 300 filters out large particles such as blood cells from the blood while allowing pressure-measuring media such as saline solution to pass freely. This avoids the risk of blood clots in the blood pressure in the conduit 100, and also prevents blood from rushing back into the blood vessels, which could cause arterial embolism, myocardial infarction, pulmonary embolism, and other consequences.

[0030] Please see Figure 1 The blood pressure sensor provided in the embodiments of this application will now be described.

[0031] The blood pressure sensor includes a tubing 100, a pressure sensor 200, and a filter 300. The tubing 100 has a first end 110 and a second end 120 disposed opposite each other. The first end 110 is used to connect to a blood vessel, and the second end 120 is used to inject a pressure-measuring medium. The pressure sensor 200 is disposed in the tubing 100 and is used to measure the liquid pressure in the tubing 100. The filter 300 is installed at the first end 110, or between the first end 110 and the pressure sensor 200. The filter 300 is used to filter blood cells in the blood entering the tubing 100 from the first end 110, and allows the pressure-measuring medium to pass through.

[0032] The first end 110 of the tubing 100 is used to connect to an indwelling needle inserted into a blood vessel, thereby connecting the tubing 100 to the blood vessel. The second end 120 of the tubing 100 is used to inject a pressure measuring medium to maintain the pressure balance of the entire tubing 100, ensuring the accuracy of the pressure sensor 200. The pressure measuring medium can be sterile saline (0.9% sodium chloride solution). To prevent blood clotting in the tubing 100, an anticoagulant can also be injected simultaneously.

[0033] It should be noted that the pressure sensor 200 is located in the pipeline 100, which means that the pressure sensor 200 is located in the path of the pipeline 100 and is connected to the pipeline 100 so that the pressure sensor 200 can accurately measure the pressure value of the liquid in the pipeline 100.

[0034] Additionally, it should be noted that the filter element 300 is installed at the first end 110 or between the pressure sensor 200 and the first end 110. The filter element 300 is used to filter blood cells in the blood entering the pipeline 100 from the first end 110. Specifically, blood generally includes plasma and blood cells, including white blood cells, red blood cells, and platelets. Large particles such as white blood cells, red blood cells, and platelets are evenly distributed in the plasma. As the blood circulates throughout the body, white blood cells, red blood cells, and platelets can aggregate and cause thrombosis. The filter element 300 filters and blocks blood cells in the blood, while allowing plasma to enter the pipeline 100. Plasma will not coagulate into thrombi in the pipeline 100, and the blood will not cause serious consequences such as arterial embolism, myocardial infarction, or pulmonary embolism when it is flushed back into the blood vessels. Furthermore, the filter element 300 allows the pressure measuring medium to pass through, thus meeting the pressure measuring requirements while preventing thrombus formation in the pipeline 100.

[0035] The blood pressure sensor in this embodiment uses a filter 300 disposed at the first end 110 of the tubing 100 or between the first end 110 and the pressure sensor 200. The filter 300 filters blood cells from the blood entering the tubing 100 from the first end 110, while allowing the pressure measuring medium to pass through. This arrangement prevents large particles such as blood cells from entering the tubing 100, thus preventing blood cells from agglomerating and forming thrombi. It also prevents blood from being flushed back into the blood vessels, which could cause serious consequences such as arterial embolism, myocardial infarction, and pulmonary embolism. Simultaneously, the filter 300 allows the pressure measuring medium to pass through, ensuring smooth pressure measurement.

[0036] In some embodiments, please refer to Figure 1 The first end 110 of the tubing 100 is provided with a connector 400, which is used to connect to a central venous catheter or arterial indwelling needle that has been inserted into a blood vessel. A filter element 300 is installed in the connector 400. Installing the filter element 300 in the connector 400 reduces the difficulty of installing the filter element 300 and simplifies the manufacturing of the tubing 100. It also prevents blood cells from entering any location within the tubing 100, reducing the risk of thrombosis and simplifying the cleaning process. Understandably, in other embodiments of this application, the filter element 300 can also be installed in the tubing 100 near the connector 400, or even anywhere within the tubing 100 between the pressure sensor 200 and the connector 400.

[0037] In some embodiments, please refer to Figure 1The filter element 300 includes a filter membrane 310, which has a porous structure. The porous structure of the filter membrane 310 filters blood cells from the blood, specifically blocking blood cells with a diameter larger than the maximum size of the pores in the filter membrane 310 on the side of the filter membrane facing the blood vessel, thereby achieving blood cell filtration. In this embodiment, the filter membrane 310 filters blood cells. Because the filter membrane 310 is relatively thin, its presence does not attenuate the pressure of the liquid flowing through it, thus reducing the impact of the filter membrane 310 on blood pressure detection. It is understood that in other embodiments of this application, the filter element 300 may also include other porous structures to filter blood cells; this is not a limiting factor.

[0038] In some embodiments, please refer to Figure 1 and Figure 2 The first end 110 of the conduit 100 is provided with a connector 400, which has a fluid channel 420 connecting the conduit 100 and the blood vessel. The filter element 300 includes a filter membrane 310, which is installed in the fluid channel 420. This arrangement not only reduces the impact of the filter membrane 310 on blood pressure detection, but also reduces the difficulty of installing the filter membrane 310.

[0039] In some embodiments, the pores in the filter membrane 310 can be circular, square, or a combination of shapes, wherein the combination shape is a closed shape formed by connecting straight lines and / or curves end to end in sequence. For example, it can be a closed shape formed by connecting multiple straight lines end to end in sequence, or it can be a closed shape formed by connecting multiple curves end to end in sequence, or it can be a closed shape formed by connecting at least one straight line and at least one curve end to end in sequence.

[0040] In some embodiments, the filter membrane 310 has through-holes with a pore size ranging from 0.01µm to 0.1µm. For example, the pore size can be 0.01µm, 0.02µm, 0.03µm, 0.04µm, 0.05µm, 0.06µm, 0.07µm, 0.08µm, 0.09µm, or 0.1µm. The pore size in the filter membrane 310 cannot be too large, as this would result in poor filtration of blood cells. Conversely, the pore size in the filter membrane 310 cannot be too small, as this would obstruct the flow of the pressure measuring medium through the filter membrane 310, affecting the rate of liquid flow and consequently attenuating the pressure of the liquid flowing through the filter membrane 310, thus impacting the accuracy of pressure detection. In this embodiment, by limiting the pore size of the through holes in the filter membrane 310 to the range of 0.01um-0.1um, the filter membrane 310 can ensure the filtering effect on blood cells in the blood pressure without attenuating the pressure of the liquid flowing through the filter membrane 310, thus ensuring the accuracy of blood pressure detection.

[0041] Regarding the diameter of a through hole, it should be noted that when the through hole is circular, the diameter is the diameter of the circle; when the through hole is non-circular, the diameter refers to the maximum distance between any two points within the through hole. For example, when the through hole is square, the diameter is the length of the perpendicular line of the square; when the through hole is elliptical, the diameter is the length of the major axis of the ellipse; when the through hole is irregularly shaped, the diameter is the distance between the two points furthest apart within the through hole.

[0042] In some embodiments, the porosity of the filter membrane 310 ranges from 85% to 95%. For example, the porosity of the filter membrane 310 can be 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, or 95%, etc. The porosity of the filter membrane 310 refers to the ratio of the area of ​​the pores in the filter membrane 310 to the total area of ​​the filter membrane 310. A higher porosity indicates a larger area occupied by the pores in the filter membrane 310; a lower porosity indicates a smaller area occupied by the pores in the filter membrane 310. Furthermore, excessively high porosity of the filter membrane 310 leads to weak overall structural strength, resulting in a shorter service life; excessively low porosity leads to greater resistance to hydraulic forces, affecting the fluid flow rate and pressure, ultimately impacting the blood pressure detection effect. In this embodiment, by controlling the porosity of the filter membrane 310 within the range of 85%-95%, the flow resistance of the filter membrane 310 to the liquid is reduced, so that the liquid can be maintained within a flow rate unit of 0.5mL / h-3mL / h, the pressure fluctuation delay of the liquid is less than 5ms, and the dynamic pressure transmission error of the liquid is less than 2 mmHg. This ensures that the continuous arterial blood pressure waveform acquisition is not distorted, and also ensures the structural strength of the filter membrane 310, ensures the assembly reliability of the filter membrane 310, and improves the service life of the filter membrane 310.

[0043] In some embodiments, the pores in the filter membrane 310 can be formed by phase separation, stretching, and track etching. Phase separation involves dissolving a polymer material in a solvent, coating it into a film, then immersing the film in a non-solvent bath to induce phase separation through solvent-non-solvent exchange, thus forming micropores. Stretching involves first calendering polytetrachloroethylene into a thin film, then stretching the film unidirectionally / bidirectionally, and finally separating at the crystal interface to form a network of micropores. Track etching involves exposing the polymer film to an ion beam to form damage tracks, and then chemically etching these tracks to form cylindrical pores.

[0044] In some embodiments, the filter membrane 310 may be made of polyethersulfone material, in which case through-pores can be formed by phase separation. Alternatively, the filter membrane 310 may also be made of polytetrachloroethylene or cellulose acetate material, in which case through-pores can be formed by stretching. Alternatively, the filter membrane 310 may also be made of polymer material, in which case through-pores can also be formed by track etching.

[0045] In some embodiments, please refer to Figure 3 At least one surface of the filter membrane 310 is coated with a functional coating 320 having hydrophilic and / or anticoagulant functions. For example, a hydrophilic functional coating 320, an anticoagulant functional coating 320, or a functional coating 320 having both hydrophilic and anticoagulant functions can be coated on one side of the filter membrane 310. Alternatively, a hydrophilic functional coating 320, an anticoagulant functional coating 320, or a functional coating 320 having both hydrophilic and anticoagulant functions can be coated on both opposite sides of the filter membrane 310.

[0046] Preferably, both sides of the filter membrane 310 are coated with a functional coating 320 that has hydrophilic and anticoagulant functions. This reduces the platelet adhesion rate on both sides of the filter membrane 310 and reduces platelet aggregation on the surface of the filter membrane 310. This not only reduces the possibility of thrombus formation at the filter membrane 310, but also reduces the obstruction of fluid flow due to platelet aggregation on the surface of the filter membrane 310.

[0047] In some embodiments, the functional coating 320 includes a heparin-chitosan coating, a type of functional coating used in the biomedical field. It can be achieved through the co-deposition of dopamine / chitosan and the electrostatic interaction between heparin and immobilized chitosan, and can be prepared within one hour, making it a simple, substrate-independent coating. The coating effectively prevents surface-induced thrombosis. Understandably, in other embodiments of this application, the functional coating 320 may also be formed using heparin coating materials, non-biologically derived antithrombotic coating materials, and heparin-agarose gel materials, etc.

[0048] In some embodiments, please refer to Figure 2 and Figure 3The filter membrane 310 includes a filter section 311 and an edge section 312 connected to the periphery of the filter section 311. The edge section 312 is used to connect with the connector 400. The thickness of the filter section 311 ranges from 0.05um to 2um. Specifically, the thickness of the filter section 311 can be 0.05um, 0.06um, 0.07um, 0.08um, 0.09um, 1um, 1.1um, 1.2um, 1.3um, 1.4um, 1.5um, 1.6um, 1.7um, 1.8um, 1.9um, or 2um. The filter membrane 310 cannot be too thin, as this would affect its structural strength and service life; conversely, the filter membrane 310 cannot be too thick, as this would affect the pressure of the liquid flowing through it and thus the accuracy of pressure detection. In this embodiment, by limiting the thickness range of the filter membrane 310 to 0.05um-2um, the structural strength of the filter membrane 310 can be guaranteed and the service life of the filter membrane 310 can be improved without affecting the pressure detection accuracy.

[0049] In some embodiments, the filter portion 311 and the edge portion 312 are integrally connected, which not only reduces the manufacturing difficulty of the filter membrane 310, but also improves the reliability of the filter membrane 310 in the connector 400. Of course, in other embodiments, under special circumstances, the filter portion 311 and the edge portion 312 may also be provided separately.

[0050] In some embodiments, the thickness of the edge portion 312 ranges from 200µm to 250µm. Specifically, the thickness of the edge portion 312 can be 200µm, 210µm, 220µm, 230µm, 240µm, or 250µm, etc. In this embodiment, by setting the thickness of the edge portion 312 of the filter membrane 310 to be much greater than the thickness of the filter portion 311, it is easier to install the edge portion 312 in the connector 400.

[0051] In some embodiments, please refer to Figure 3 The inner peripheral wall of the connector 400 has an annular groove 410, and the edge portion 312 is inserted into the annular groove 410 to form a connection. Specifically, the edge portion 312 can be embedded into the annular groove 410 by interference fit. Alternatively, after the edge portion 312 is inserted into the annular groove 410, an adhesive can be filled between the edge portion 312 and the inner wall of the annular groove 410 to improve the assembly reliability of the edge portion 312 in the annular groove 410. In addition, in other embodiments, after the edge portion 312 is inserted into the annular groove 410, it can be fixed in the annular groove 410 by fasteners such as rivets and locking members.

[0052] In some embodiments, please refer to Figure 3The filter membrane 310 is perpendicular to the length of the fluid channel 420. Liquid flows along the length of the fluid channel 420, meaning the filter membrane 310 is perpendicular to the liquid flow direction. When blood flows perpendicularly through the filter membrane 310, the filter membrane 310 will not block blood cells and can reduce the accumulation of residual blood cells on the surface of the filter membrane 310. Furthermore, the perpendicular orientation of the filter membrane 310 to the liquid flow reduces the time and resistance of the liquid flowing through the filter membrane 310, and minimizes the attenuation of liquid pressure on the filter membrane 310. It is understood that in other embodiments of this application, the filter membrane 310 may also be configured to be slightly inclined relative to the direction perpendicular to the fluid flow direction; this is not a limiting factor.

[0053] In some embodiments, please refer to Figure 1 The blood pressure sensor also includes an infusion device 500, which is installed at the second end 120 of the pipeline 100. The infusion device 500 is used to inject the pressure measuring medium into the pipeline 100 to maintain the pressure balance of the entire pipeline 100, so as to ensure the accuracy of the measurement by the pressure sensor 200.

[0054] In some embodiments, please refer to Figure 1 The blood pressure sensor also includes a flow regulator 600, which is located between the infusion unit 500 and the pressure sensor 200. The flow regulator 600 is used to regulate the flow rate of the liquid entering the infusion unit 500.

[0055] In some embodiments, please refer to Figure 1 The pressure sensor 200 is connected to a connector 700, which is used to connect to a monitor, thereby detecting the data detected by the pressure sensor 200 and implementing control.

[0056] In some embodiments, please refer to Figure 1 A three-way valve 800 is provided between the pressure sensor 200 and the connector 400. The three-way valve 800 is mainly used to connect and control the pressure measuring line 100 and related equipment. Specifically, the three-way valve 800 can connect the pressure sensor 200 and the pressure measuring line 100, or it can connect to devices such as infusion sets or syringes. In clinical operations, the three-way valve 800 can perform multiple functions. For example, by adjusting the position of the three-way valve 800, blood can be drawn and monitored without re-puncturing the patient's blood vessels, thereby reducing patient pain and the risk of infection. When multiple blood pressure monitoring channels are required, the three-way valve 800 can connect multiple sensors, enabling quick plugging and unplugging and branching functions, which helps improve monitoring efficiency and ensure the accuracy of different pressure measurement signals. In addition, the three-way valve 800 may also be used to control the connection of the infusion or aspiration line 100, facilitating infusion or other medical procedures while measuring blood pressure.

[0057] In some embodiments, please refer to Figure 1 The blood pressure sensor also includes a protective cap 900. The protective film is used to cover the connector 400 when the blood pressure sensor is not in use, in order to protect the connector 400 and prevent external substances from entering the tubing 100.

[0058] In some embodiments, please refer to Figure 1 The blood pressure sensor includes a sensor unit 210 and a housing 220. The sensor unit 210 is installed in the path of the pipeline 100 and is connected to the pipeline 100. The housing 220 is installed outside the sensor unit 210 and is used to realize the installation of the sensor unit 210 in the pipeline 100.

[0059] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A blood pressure sensor, characterized in that, include: The tubing has a first end and a second end that are arranged opposite to each other. The first end is used to connect to a blood vessel, and the second end is used to inject a pressure measuring medium. A pressure sensor is installed in the pipeline and is used to measure the liquid pressure in the pipeline; A filter element is installed at the first end, or between the first end and the pressure sensor; the filter element is used to filter blood cells in the blood entering the pipeline from the first end, and the filter element allows the pressure measuring medium to pass through.

2. The blood pressure sensor as described in claim 1, characterized in that, The first end of the pipeline is provided with a connector, and the filter element is installed in the connector; or, the filter element is installed in the pipeline near the connector.

3. The blood pressure sensor as described in claim 1, characterized in that, The filter element includes a filter membrane, which has a porous structure.

4. The blood pressure sensor as described in claim 1, characterized in that, The first end of the pipeline is provided with a connector, the connector having a fluid channel communicating with the pipeline; the filter element includes a filter membrane, the filter membrane being installed in the fluid channel.

5. The blood pressure sensor as described in claim 3 or 4, characterized in that, The filter membrane has through pores with a pore size ranging from 0.01µm to 0.1µm.

6. The blood pressure sensor as described in claim 3 or 4, characterized in that, The porosity of the filter membrane ranges from 85% to 95%.

7. The blood pressure sensor as described in claim 3 or 4, characterized in that, At least one side of the filter membrane is coated with a functional coating that has hydrophilic and / or anticoagulant properties.

8. The blood pressure sensor as described in claim 7, characterized in that, The functional coating includes a heparin-chitosan coating.

9. The blood pressure sensor as described in claim 4, characterized in that, The filter membrane includes a filter section and an edge section connected to the periphery of the filter section. The edge section is used to connect with the connector. The thickness of the filter section ranges from 0.05µm to 2µm.

10. The blood pressure sensor as described in claim 4, characterized in that, The filter membrane is perpendicular to the length extension direction of the fluid channel.

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