Passive anorectum pressure measuring device

Abstract

The invention provides a passive anorectum pressure measuring device. The passive anorectum pressure measuring device comprises a pressure measuring device body and an expandable balloon, the pressure measuring device body is of a flexible tubular structure with a cavity and comprises an air inlet section, a detection section and an inflation section which are sequentially arranged in the direction from the near end to the far side of the pressure measuring device body, the expandable balloon is connected with the wall of the flexible tubular structure of the pressure measuring device body, the inflation section extends into the expandable balloon, an air hole is formed in the inflation section, and the air hole is communicated with the inflation section. The inflation section is communicated with gas in the expandable balloon through the gas hole; a multistable cell string is arranged in the cavity of the detection section; the air inlet section is provided with a connector used for being connected with an external air source. The pressure measuring device provided by the invention does not need external source connection, so that the portability and usability of the pressure measuring device are improved.

Description

Technical Field

[0001] The invention relates to the field of medical instruments, and in particular to a passive anorectal pressure measuring device. Background Art

[0002] At present, anorectal function assessment needs to be completed with the help of anorectal manometry in clinical practice. Surgeons rely on anorectal manometry to understand the patient's anorectal function, and then accurately assess the patient's anorectal function and formulate a reasonable treatment plan.

[0003] At present, the relevant research work carried out by domestic and foreign researchers in the field of anorectal pressure measuring devices mainly focuses on the integration of sensors, lacks practical research on portable devices, and does not meet the needs of convenience and ease of use in clinical practice. A comprehensive analysis of the existing technologies shows that there are three main problems: Insufficient portability: The existing pressure measuring devices based on piezoelectric sensors require power supply, and the range of movement is greatly limited. During use, it is difficult to achieve portable use in various environments; Insufficient ease of use: The existing pressure measuring devices usually need to be equipped with bulky acquisition instrument hardware to collect and decode the measured electric field, and must be subjected to complex calculations and processing through dedicated computer software, and the measurement data cannot be obtained intuitively; Poor accuracy: The anal canal pressure measured by the existing airbag method is actually a section of pressure rather than a point. Due to the compressibility of air, the transmitted pressure wave is weakened, and the response frequency is poor, resulting in poor accuracy and sensitivity, which is easily affected by human factors and has large differences.

[0004] Therefore, designing a portable, easy-to-use anorectal manometry device that allows surgeons to immediately complete anorectal function assessment for patients in the outpatient clinic is crucial for the diagnosis and treatment of patients with related diseases and the development of the discipline. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the related art. To this end, the present invention provides a passive anorectal pressure measuring device.

[0006] The present invention provides a passive anorectal pressure measuring device, comprising: The manometry device body and the expandable balloon; The pressure measuring device body is a flexible tubular structure with a cavity, comprising an air intake section, a detection section and an air filling section arranged in sequence from the proximal end to the distal end of the pressure measuring device body. The expandable balloon is connected to the flexible tubular structure wall of the pressure measuring device body, the inflatable section extends into the expandable balloon, and an air hole is provided on the inflatable section, and the inflatable section is connected to the internal gas of the expandable balloon through the air hole; A multi-stable cell string is arranged in the cavity of the detection section; The air inlet section is provided with an interface for connecting with an external air source.

[0007] According to a passive anorectal pressure measuring device provided by the present invention, when the inflation section extends into the first area to be tested, gas is supplied to the air inlet section from an external air source. After the gas enters the air inlet section, the gas enters through the air holes of the inflation section and fills the expandable balloon to form an expansion structure. The expansion structure is used to resist the boundary structure of the first area to be tested to detect the pressure change in the first area to be tested.

[0008] According to a passive anorectal pressure measuring device provided by the present invention, when the expandable balloon forms an expansion structure, the air intake section is closed so that the pressure measuring device body and the expandable balloon form a closed structure, and when the expansion structure presses against the boundary structure of the first area to be measured, the pressure change in the first area to be measured causes the gas pressure inside the expansion structure to change, and the gas pressure change in the expansion structure is transmitted to the multi-stable cell string in the detection section.

[0009] According to a passive anorectal pressure measuring device provided by the present invention, the multistable cell string includes a plurality of multistable cells connected in series, and the plurality of multistable cells connected in series generate multi-level deformation in response to the change of gas pressure in the first area to be measured.

[0010] According to a passive anorectal pressure measuring device provided by the present invention, the multistable cell is a curved beam structure, wherein the curved beam structure deforms when subjected to pressure.

[0011] According to a passive anorectal pressure measuring device provided by the present invention, each multistable cell of the multistable cell string arranged in series in the detection segment cavity serves as a first multistable cell, and on the peripheral side of each first multistable cell, a plurality of second multistable cells are connected in parallel with the first multistable cell, and radiate outward with the first multistable cell as the center. When the detection segment is placed in the second area to be tested (for example, the anal canal area), the subject to be tested performs actions such as contracting the anus, simulating defecation, coughing, etc. according to the instructions, or quickly injecting air or water into the rectum to induce the rectal anal inhibition reflex. At this time, the flexible tubular structure wall at the detection segment deforms in response to the pressure change of the anal sphincter, and generates a compressive force on the air in the detection segment cavity from the circumferential direction, and the second multistable cells deform in response to the compressive force.

[0012] According to a passive anorectal pressure measuring device provided by the present invention, a line connecting midpoints of curved beams of a plurality of the first multistable cells is collinear with an axis of a body of the pressure measuring device.

[0013] According to a passive anorectal pressure measuring device provided by the present invention, the directions of the curved beams of the plurality of second multistable cells connected in parallel are arranged to withstand the circumferential pressure changes of the detection section cavity.

[0014] A passive anorectal manometry device according to the present invention further comprises: Multiple pressure sensors; A plurality of pressure sensors are arranged on the curved beams of the multistable cell.

[0015] A passive anorectal manometry device according to the present invention further comprises: Operating handle; The operating handle is sleeved on the air intake section.

[0016] The passive anorectal pressure measuring device of the present invention uses the deformation of a multi-stable cell string in the longitudinal direction of the pressure measuring device body to reflect the pressure change in the rectal cavity, avoiding the pressure attenuation caused by air compression, and has high accuracy and sensitivity. The response of the multi-stable cell string to pressure is achieved through its own deformation, and no external power supply is required, so it is a passive device.

[0017] In the circumferential direction of the detection section, the pressure changes from the anal sphincter on a plane can be measured by the parallel multistable cells arranged along the circumference. The changes in the multistable cell curved beams can reflect the pressure changes in all directions on the circumference. In addition, the asymmetry of the anal sphincter pressure can also be reflected by the different changes in the curved beams of each parallel multistable cell in the circumference. Therefore, the asymmetric pressure changes of the anal sphincter can be detected. The parallel multistable cells arranged in the longitudinal direction can detect the pressure changes of the inner and outer sphincters in the anal canal area. The function of the anal sphincter can be comprehensively evaluated by the combination of circumferential and longitudinal parallel multistable cell strings. It overcomes the disadvantage that the existing rectal manometry device cannot measure single-point pressure when measuring anal canal pressure.

[0018] The pressure measuring device provided by the present invention does not require external hardware equipment for data collection and decoding. Through mechanical principles, the pressure measuring device responds to its own deformation, and then according to calibration or conversion, it quickly reads and converts various key indicators after pressure measurement to complete the measurement, forming a passive pressure measuring structure, thereby improving the portability and ease of use of the pressure measuring device.

[0019] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 It is a schematic structural diagram of a passive anorectal manometry device provided by an embodiment of the present invention; Figure 2 is a forward schematic diagram of an unpressurized state of a multi-stable cell string in a passive anorectal manometry device provided by an embodiment of the present invention; Figure 3 It is a schematic diagram of a multi-stable cell string in an unpressurized state in a passive anorectal pressure measurement device provided by an embodiment of the present invention.

[0022] Figure 4 It is a schematic diagram of a passive anorectal manometry device provided by an embodiment of the present invention in a working state.

[0023] Reference numerals: 100. Pressure measuring device body; 110. Air inlet section; 120. Detection section; 130. Inflatable section; 140. Air hole; 200. Expandable balloon; 300. Multistable cell string; 310. First multistable cell; 320. Second multistable cell. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments, and they should not be understood as limitations on the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. In the description of the present invention, it should be understood that the terms used are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0025] In this specification, when "distal" or "distal end" is mentioned, it refers to the side close to the object to be measured or the area to be measured, that is, the side away from the air inlet section of the pressure measuring device body. In this specification, when "proximal" or "proximal end" is mentioned, it refers to the side of the air inlet section of the pressure measuring device body, that is, the side away from the object to be measured or the area to be measured.

[0026] Combine the following Figures 1 to 4 Embodiments of the present invention are described.

[0027] like Figure 1 As shown, the present invention provides a passive anorectal manometry device, comprising: The pressure measuring device body 100 and the expandable balloon 200; The pressure measuring device body 100 is a flexible tubular structure having a cavity, and includes an air intake section 110, a detection section 120 and an inflation section 130 which are sequentially arranged from the proximal end to the distal end of the pressure measuring device body 100. The expandable balloon 200 is connected to the flexible tubular structure wall of the pressure measuring device body 100, the inflatable section 130 extends into the expandable balloon 200, and an air hole 140 is provided on the inflatable section, and the inflatable section 130 is in gas communication with the inside of the expandable balloon 200 through the air hole 140; A multi-stable cell string 300 is arranged in the cavity of the detection section 120; The air inlet section 110 is provided with an interface for connecting to an external air source.

[0028] like Figure 4 As shown, an air hole is provided on the inflation section of the pressure measuring device body, and the inflation section and the expandable balloon of the pressure measuring device body are used to extend into the rectal cavity of the object to be tested, the detection section is arranged in the anal canal area of ​​the object to be tested, and the air intake section is usually arranged outside the body of the object to be tested.

[0029] like Figure 4 As shown in , in the working state, that is, when the expandable balloon is inflated to form an expanded structure and presses against the boundary structure in the rectal cavity (i.e., the inner wall of the rectum), in response to the change in the gas pressure inside the expanded structure, it can be seen from the small right picture of the magnified detection section that the multistable cell string 300 is deformed as a whole, from the pre-deformation shape on the left to the compressed deformation shape on the right. Figure 4 As can be seen in the figure, the multi-stable cell string 300 is arranged in the detection section of the pressure measuring device body 100, that is, the position of the pressure measuring device body 100 corresponding to the anal canal area of ​​the subject to be tested. When testing the anal function, the subject to be tested needs to hold his breath or perform specific anal sphincter movements to measure the pressure changes in the anal canal to detect various indicators reflecting the anal function.

[0030] In a specific embodiment, the length of the manometry device body is 30-120 cm, wherein the length of the detection section is greater than the length of the anal canal region of the subject to be tested. Since the length of the anal canal region of a normal adult is 2.5-4 cm, the length of the detection section may be at least greater than 4 cm. In another specific embodiment, the length of the detection section may be less than the length of the anal canal region of the subject to be tested.

[0031] In one embodiment, the gas supplied by the external gas source may be air or carbon dioxide.

[0032] Among them, when the inflation section extends into the first area to be tested, gas is supplied to the air inlet section by an external gas source. After entering the air inlet section, the gas enters through the air holes of the inflation section and fills the expandable balloon 200 to form an expansion structure. The expansion structure presses against the boundary structure of the first area to be tested to detect the pressure changes in the first area to be tested.

[0033] In a specific embodiment, the first area to be tested is the rectal cavity.

[0034] Among them, when the expandable balloon 200 forms an expanded structure, the air inlet section 110 is closed to make the pressure measuring device body 100 and the expandable balloon 200 form a closed structure. When the expanded structure presses against the boundary structure of the first area to be measured, the pressure change in the first area to be measured causes the gas pressure inside the expanded structure to change. The gas pressure change in the expanded structure is transmitted to the multistable cell string 300 in the detection section 120, thereby causing the deformation of the multistable cell string.

[0035] Furthermore, a valve may be provided on the air inlet section 110, and when the expandable balloon 200 is inflated to form an expanded structure, for example, a sphere, the operator may close the valve. In another embodiment, a flange may be provided on the air inlet section to connect to a pipeline of an external gas source, and a valve or other flow control device on the external gas source pipeline may be used to cut off or start the gas delivery.

[0036] In one embodiment, the material of the expandable balloon can be medical-grade silicone material, which has good elasticity and biocompatibility. When measuring pressure, the elastic expansion structure made of silicone can first fit the inner wall structure of the rectum, and when there is a pressure change in the rectum, it can also have good deformation performance to meet different measurement requirements.

[0037] The multistable cell string 300 includes a plurality of multistable cells connected in series, and the plurality of multistable cells connected in series generate multi-level deformation in response to the change of gas pressure in the first region to be measured.

[0038] Furthermore, the curved beam exhibits more complex characteristics when subjected to stress, including the coupling of axial deformation and in-plane bending, the coupling of vertical flexure and torsion, and the coupling with cross-sectional distortion. Among them, the most important is the coupling of flexural deformation and torsion deformation, that is, the curved beam will produce bending and torque at the same time under the action of vertical load and torque, and they will affect each other.

[0039] When a curved beam structure is subjected to external pressure, its geometric shape can produce large deformation or displacement. This deformation or displacement can be directly captured by the pressure sensor and converted into electrical signals or other forms of processable data. That is to say, when a curved beam is subjected to pressure, due to the existence of "bending-torsion" coupling, the principal tensile stress of its cross section is greater, thereby increasing its sensitivity to pressure changes.

[0040] Among them, each multistable cell of the multistable cell string 300 arranged in series in the detection section cavity serves as a first multistable cell 310, and on the periphery of each first multistable cell 310, a plurality of second multistable cells 320 are connected in parallel with the first multistable cell 310 and radiate outward with the first multistable cell 310 as the center.

[0041] In one embodiment, a plurality of multistable cells connected in parallel present a "petal-like" structure, wherein a multistable cell string longitudinally arranged in a cavity serves as a central multistable cell string, and each multistable cell of the central multistable cell string, i.e., a first multistable cell 310, serves as a central multistable cell. Along the circumference of the detection section cavity, on the plane of each central multistable cell, multistable cells connected in parallel, i.e., a second multistable cell 320, radiate outward with the central multistable cell as the center.

[0042] Further, such as Figure 2 and Figure 3 As shown, multiple multistable cells arranged in the length direction of the pressure measuring device body, that is, multiple first multistable cells 310 are all arranged in series, and the curved beam structures of the multistable cell string 300 are all upward, and the curved beam structure of each relatively lower multistable cell is connected to the bottom of the adjacent multistable cell through a connecting axis.

[0043] Furthermore, on the peripheral side of each first multistable cell, a plurality of second multistable cells located in the same plane are connected in parallel, and the curved beam structure of each second multistable cell is connected to the peripheral side surface of the corresponding first multistable cell through a connecting axis.

[0044] Figures 2 to 3 FIG. 3 is a schematic diagram of the structure of the multistable cell string 300 in an uncompressed state, that is, a fully expanded form of the multistable cell string. Figure 2 is the front view of the unstressed state of the multistable cell string, Figure 3 A top view of the multistable cell string in its unstressed state.

[0045] Depend on Figure 2It can be seen that the multistable cell string 300 is provided with a plurality of first multistable cells connected in series in the axial direction, and a plurality of second multistable cells are evenly arranged in the circumferential direction of each axial first multistable cell, and the second multistable cells are perpendicular to the axis of the first multistable cells. This structural setting enables the multistable cell string to sensitively change its shape no matter which direction it is compressed, and the change shape of the multistable cell string may also be a full expansion mode (not compressed), a full deformation mode (compressed in all directions), an axial deformation mode only (compressed in the axial direction only), a circumferential deformation mode only (compressed in all directions only in the circumferential direction), and a circumferential partial deformation mode (compressed in only a partial circumferential direction), which can be used for multiple areas (i.e., the first area to be tested and the second area to be tested, in Figure 4 In the embodiment shown, comprehensive sensing is performed on the pressure change areas of the rectal cavity and anal canal area.

[0046] The line connecting the midpoints of the curved beams of the first multi-stable cells 310 is collinear with the axis of the pressure measuring device body 100 .

[0047] The direction of the curved beam of the parallel second multistable cell 320 is set to withstand the circumferential pressure change of the detection section cavity, so that the parallel second multistable cell 320 can detect the pressure change of the second test area where the detection section is located.

[0048] In one embodiment, the second area to be detected may be the anal canal area. Preferably, the length of the detection segment may be greater than the anal canal area, so that the pressure changes generated by the contraction of the internal anal sphincter and the external anal sphincter can be detected simultaneously through a plurality of second multistable cells connected in parallel in the longitudinal direction. Of course, in another embodiment, the length of the detection segment may be less than the length of the anal canal area, so that the pressure changes of only the internal anal sphincter or only the external anal sphincter can be detected by changing the placement position of the detection segment.

[0049] In one embodiment, the curved beam of the first multistable cell is arranged to face the longitudinal axis of the cavity to withstand longitudinal pressure changes. In rectal manometry, deformation of the curved beam of the first multistable cell reflects pressure changes in the rectal cavity.

[0050] In one embodiment, the curved beams of the second multistable cells connected in parallel are arranged to face the circumference of the cavity to withstand the pressure changes from the circumference. Figure 4 As shown in the figure, in rectal manometry, the detection segment is placed in the anal canal of the subject to be tested, so that the deformation of the curved beam of the parallel multistable cells can reflect the pressure changes of the anal sphincter. When performing anal sphincter pressure testing, doctors will evaluate several key indicators, including maximum voluntary contraction pressure, defecation pressure, resting pressure, sphincter pressure changes during coughing, rectal anal inhibitory reflex (RAIR), and rectal volume sensory threshold.

[0051] In a specific embodiment, the parallel multistable cells may be 4, 6, 8, or 10 multistable cells connected in parallel with a central multistable cell, preferably 8.

[0052] In the present invention, the multistable cell string adopts a "petal-like" structure, that is, a combination of a first multistable cell ("stamen") and a second multistable cell ("petal") in parallel. Multiple first multistable cells are connected in series to reflect the pressure change in the rectal cavity through the deformation of multiple multistable cells. The curved beam of each parallel second multistable cell faces the circumference of the cavity. Therefore, each petal of the "petal-like" structure is on the same plane, such as Figure 3 In the embodiment, one first multistable cell and eight parallel second multistable cells can reflect the pressure changes in all directions along the circumference of the detection section cavity. In the longitudinal direction, the multiple second multistable cells on the central axis of the pressure measuring device body cavity can reflect the pressure changes of the internal and external anal sphincters along the length of the anal canal area, see Figure 4 .

[0053] By utilizing the multi-stable cell string configuration of the "petal-like" structure of the passive anorectal pressure measuring device of the present invention, the curved beams of multiple parallel second multi-stable cells serving as "petals" can also measure the asymmetric changes in anal sphincter pressure. This pressure deviation phenomenon is helpful for anal continence and can also serve as a reliable indicator for evaluating the efficacy of biofeedback training.

[0054] Furthermore, the series design can increase the response amplitude of the system. Since the deformation or displacement of the cell string can be superimposed, the response of the entire device to pressure changes is more significant, thereby improving the sensitivity and accuracy of the measurement.

[0055] In one embodiment, the passive anorectal manometry device 100 further comprises: Multiple pressure sensors; A plurality of pressure sensors are arranged on the curved beams of the multistable cell.

[0056] In one embodiment, when the multistable cell is a curved beam structure, a pressure sensor can be provided on the curved beam of the multistable cell. In response to pressure changes, the curved beam deforms, and the pressure sensor provided on the curved beam can detect the pressure changes borne by the curved beam.

[0057] Furthermore, when the cells in the multistable cell string are subjected to external pressure, they can be deformed according to the change of external pressure. This deformation includes not only the relative position change between the microscopic cells, but also the macroscopic shape change of the entire cell string. In the pressure measurement for the anorectum, the multistable cell string acts as a sensitive element, converting the pressure change in the measured area into a measurable deformation.

[0058] Furthermore, the pressure sensor is a device for detecting the deformation field data of the multistable cell string, which can capture the deformation information of the multistable cell string under pressure and convert it into electrical signals or other forms of processable data. When the multistable cell string is deformed, the physical quantities inside the pressure sensor, such as resistance, capacitance, inductance, etc., will change accordingly, thereby generating a measurable signal, which is then transmitted wirelessly to an external computing device for subsequent pressure calculation and analysis.

[0059] In one embodiment, an external computing device (e.g., an industrial computer, a single-chip microcomputer, or a personal computer, etc.) can be used to receive the deformation field data output by the pressure sensor, and the pressure field data of multiple test areas (e.g., the rectal cavity and anal canal area) can be calculated according to a preset mapping relationship, and the results can then be displayed to the user in a visual or other form.

[0060] In one embodiment, the passive anorectal manometry device 100 further comprises: Operating handle; The operating handle is sleeved on the air inlet section of the pressure measuring device body.

[0061] Furthermore, the operating handle can be used by the operator to hold the pressure measuring device 100 and operate the air intake, air exhaust and closing of the pressure measuring device 100.

[0062] A passive anorectal pressure measuring device provided by the present invention is a passive pressure measuring structure. Through the response of the self-deformation of the multi-stable cell string, through the recommended calibration or conversion, the various key indicators after the pressure measurement are quickly read and converted, that is, the pressure measurement without the addition of an external power supply and equipment can be completed. The device is highly portable and easy to use, and can enable the physician to grasp the relevant conditions of the patient's anorectal function in the first time, accurately evaluate the condition of the patient's anorectal function, formulate a reasonable treatment plan, and improve convenience, economy and timeliness.

[0063] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0064] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A passive anorectal manometry device, characterized in that: include: The manometry device body and the expandable balloon; The pressure measuring device body is a flexible tubular structure with a cavity, comprising an air intake section, a detection section and an air filling section arranged in sequence from the proximal end to the distal end of the pressure measuring device body. The expandable balloon is connected to the flexible tubular structure wall of the pressure measuring device body, the inflatable section extends into the expandable balloon, and an air hole is provided on the inflatable section, and the inflatable section is connected to the internal gas of the expandable balloon through the air hole; A multi-stable cell string is arranged in the cavity of the detection section; The air inlet section is provided with an interface for connecting with an external air source.

2. A passive anorectal manometry device according to claim 1, characterized in that: When the inflation section extends into the first area to be tested, gas is supplied to the air inlet section from an external gas source. After entering the air inlet section, the gas enters through the air holes of the inflation section and fills the expandable balloon to form an expansion structure. The expansion structure is used to resist the boundary structure of the first area to be tested to detect the pressure changes in the first area to be tested.

3. A passive anorectal manometry device according to claim 2, characterized in that: When the expandable balloon forms an expanded structure, the air inlet section is closed so that the pressure measuring device body and the expandable balloon form a closed structure. When the expanded structure presses against the boundary structure of the first area to be measured, the pressure change in the first area to be measured causes the gas pressure inside the expanded structure to change. The gas pressure change in the expanded structure is transmitted to the multistable cell string in the detection section.

4. A passive anorectal manometry device according to claim 3, characterized in that: The multistable cell string includes a plurality of multistable cells connected in series, and the plurality of multistable cells connected in series generate multi-level deformation in response to the change of gas pressure in the first area to be measured.

5. A passive anorectal manometry device according to claim 4, characterized in that: The multistable cell is a curved beam structure, wherein the curved beam structure deforms when subjected to pressure.

6. A passive anorectal manometry device according to claim 4, characterized in that: Each multistable cell in the multistable cell string arranged in the detection section cavity serves as a first multistable cell. On the periphery of each first multistable cell, a plurality of second multistable cells are connected in parallel with the first multistable cell and radiate outward with the first multistable cell as the center.

7. A passive anorectal manometry device according to claim 6, characterized in that: A line connecting the midpoints of the curved beams of the first multistable cells is collinear with the axis of the pressure measuring device body.

8. A passive anorectal manometry device according to claim 6, characterized in that: The direction of the curved beam of the parallel second multistable cell is set to withstand the circumferential pressure change of the detection section cavity, so that the parallel second multistable cell can detect the pressure change of the second test area where the detection section is located.

9. A passive anorectal manometry device according to claim 1, characterized in that: Also includes: Multiple pressure sensors; A plurality of pressure sensors are arranged on the curved beams of the multistable cell.

10. A passive anorectal manometry device according to claim 1, characterized in that: Also includes: Operating handle; The operating handle is sleeved on the air intake section.

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