Lung tissue specimen fixing device and method capable of adjusting and displaying perfusion pressure

Abstract

The invention relates to the technical field of lung tissue diagnosis, in particular to a lung tissue specimen fixing device and method capable of adjusting and displaying perfusion pressure, which comprises a fixing container, a pressure linkage cylinder, a U-shaped pressure gauge, an air pressure buffer and a pressure regulator, through cooperative use of a fixed container, a pressure linkage cylinder, a U-shaped pressure gauge, an air pressure buffer and a pressure regulator, the pressure borne by lung tissue can be monitored in real time in the process that the lung tissue passively sucks stationary liquid, and the pressure is kept under the condition of functional residual gas pressure; the U-shaped pressure gauge can accurately detect the pressure value borne by the lung tissue, and meanwhile potential damage possibly caused by the reverse acting force of detection liquid in the U-shaped pressure gauge to the lung tissue is avoided. The technical problem that according to an existing fixing method, due to individual differences of animals, lung overpressure of some individuals is caused, and potential tissue damage or different alveolar expansion is caused is solved.

Description

Technical Field

[0001] The invention relates to the technical field of lung tissue diagnosis, and in particular to a lung tissue specimen fixing device and method capable of adjusting and displaying perfusion pressure. Background Art

[0002] At present, the most commonly used lung tissue fixation method is to cut the lung tissue into small pieces and directly put them into the fixative and cover the lungs with gauze to prevent the lung tissue from floating to the surface of the liquid. This fixation method causes the natural shrinkage of the lung tissue after being removed from the body and still contains a large amount of gas, which leads to slow penetration of the fixative. Over time, it may cause cell autolysis, ultimately leading to alveolar atrophy and collapse, tissue damage and other problems that affect the evaluation of pathological test results.

[0003] Methods to solve these problems include: (1) tying off the main trachea before removing the lung from the body, so that the lung tissue is in a certain state of expansion, and then hanging a heavy object to make the lung tissue sink into the fixative. This method cannot solve the problems of alveolar atrophy and tissue damage due to the large amount of gas in the lung tissue and the surrounding water pressure; (2) placing the lung tissue in a closed environment to create negative pressure conditions for the closed environment. The generation of negative pressure causes the gas in the lung tissue to be discharged. This method is conducive to the penetration of the fixative, but it cannot solve the problem of alveolar atrophy and collapse; (3) fixing the lung tissue by directly perfusing the fixative through the main trachea. This method cannot expel the original gas. The active pressurized perfusion method may also cause potential structural damage to the lung tissue due to the different size and structure of the main and bronchi of the lung. Problems such as different liquid flow pressure and direction; (4) simulating normal breathing, changing the external pressure of the lung to discharge the gas, and passively inhaling the fixative. This method can keep the lung tissue in a good structure and fixation effect.

[0004] However, this method cannot determine the pressure value applied to the lung tissue. The method of estimating lung volume through experimental body weight and inhaling a certain amount of fixative may cause potential tissue damage or different alveolar expansion due to individual differences in animals, which may ultimately lead to different comparison conditions for research results. In addition, according to the official seminar report of the American Thoracic Society, reliable histological assessment of lung injury requires the lung to be correctly fixed at functional residual capacity, even if the lung tissue is maintained in an expanded state of 15-20cm water column pressure. At present, no pathological fixation device that can detect the pressure of lung tissue has been found. Summary of the invention

[0005] The purpose of the present invention is to provide a lung tissue specimen fixation device and method that can adjust and display the perfusion pressure, which solves the problem that the existing fixation method cannot determine the pressure value applied to the lung tissue. The method of estimating the lung volume by experimental body weight and inhaling a certain amount of fixative may cause overpressure in the lungs of some individuals due to individual differences in animals, resulting in potential tissue damage or different alveolar expansion, which ultimately leads to different comparison conditions for research results.

[0006] To achieve the above-mentioned purpose, the present invention provides a lung tissue specimen fixing device that can adjust and display perfusion pressure, including a fixing container, a pressure linkage cylinder, a U-shaped pressure gauge, a pneumatic buffer and a pressure regulator, wherein a first connecting tube and a second connecting tube extend into the fixing container, the first connecting tube is connected to the pressure linkage cylinder, the second connecting tube is connected to the pressure regulator, the U-shaped pressure gauge is connected to the pressure linkage cylinder and is located on a side of the pressure linkage cylinder away from the first connecting tube, the pneumatic buffer is respectively connected to the U-shaped pressure gauge and the pressure regulator, and the pneumatic buffer is located between the U-shaped pressure gauge and the pressure regulator.

[0007] Among them, a first pressure-linked piston is arranged in the pressure-linked cylinder, and the first pressure-linked piston divides the internal space of the pressure-linked cylinder into two left and right chambers. The left chamber is a fixed liquid chamber, and the right chamber is an air chamber.

[0008] Wherein, a fixing groove is arranged on the outer side of the pressure regulator, and the pressure regulator is fixed outside the fixing plate through the fixing groove.

[0009] Among them, a second pressure-linked piston is arranged in the pressure regulator, and the second pressure-linked piston divides the internal space of the pressure regulator into two left and right chambers, the left chamber is the first air chamber, and the right chamber is the second air chamber.

[0010] Wherein, a piston limiting protrusion is arranged in the pressure regulator, and the piston limiting protrusion is used to limit the extreme position of the second pressure linkage piston.

[0011] Among them, a piston connecting rod, a pressure adjusting stud and a limiter are arranged outside the second pressure-linked piston, the piston connecting rod is arranged above the second pressure-linked piston, the pressure adjusting stud is arranged on the side of the piston connecting rod away from the second pressure-linked piston, and the limiter is used to limit and fix the position of the pressure adjusting stud.

[0012] The present invention also provides a lung tissue specimen fixing method capable of adjusting and displaying perfusion pressure, comprising the following steps:

[0013] The intact lung tissue without leakage is ligated and fixed to the second tube opening of the first connecting tube, and the sealing cover is tightly closed to make the fixed container in a sealed state;

[0014] Then, the pipe port 3 of the second connecting pipe is connected to the connecting port 1 of the pressure regulator by a pipe, and the pressure regulating nut is turned to compress the first air chamber, so that the air pressure compresses the lung tissue in the fixed container and discharges the gas in the lung;

[0015] Afterwards, the pipe opening of the first connecting pipe is connected to the connecting opening of the pressure linkage cylinder by the pipe, and before the connection, the pipe cavity between the lung tissue and the fixing liquid chamber is filled with fixing liquid;

[0016] Then, the pipeline is used to connect the second communication port of the pressure linkage cylinder and the first communication port of the U-shaped pressure gauge, and the second communication port of the pressure regulator is connected to the first communication port of the air pressure buffer, and the second communication port of the air pressure buffer is connected to the second communication port of the U-shaped pressure gauge;

[0017] The pressure regulating nut is turned to expand the air chamber, so that negative pressure is generated between the fixed container and the outside of the lung, and the negative pressure drives the lung tissue to expand, and while the lung tissue expands, the fixing liquid in the pipeline is absorbed;

[0018] While the fixing liquid is being sucked, the reduction of the fixing liquid in the fixing liquid chamber causes the first pressure-linked piston to move toward the fixing liquid chamber;

[0019] At this time, the expansion of the air cavity generates negative pressure, which causes the liquid level on one side of the U-shaped pressure gauge to rise and the liquid level on the other side to drop, and the pressure on the lung tissue is obtained by reading the difference between the two liquid levels.

[0020] The present invention discloses a lung tissue specimen fixing device and method capable of adjusting and displaying perfusion pressure. Through the coordinated use of the fixing container, the pressure linkage cylinder, the U-shaped pressure gauge, the air pressure buffer and the pressure regulator, the pressure borne by the lung tissue can be monitored in real time during the process of passively absorbing the fixing liquid, and the pressure can be maintained under the functional residual capacity pressure condition. In addition, a negative pressure compensation circuit is designed, so that the U-shaped pressure gauge can accurately detect the pressure value borne by the lung tissue while avoiding the potential damage to the lung tissue caused by the reverse force of the detection liquid in the U-shaped pressure gauge, thereby achieving better fixation of the lung tissue to form a specimen, while avoiding the structural damage of the tissue caused by the fixing liquid pressure exceeding the bearing range of the lung tissue through pressure monitoring. Through pressure monitoring and adjustment, the lung tissue can be placed in a better natural expansion state for lung pathology observation reported in the literature, and specimens of different individuals can be placed at the same pressure level, so that the microscopic structure of the lung tissue slice can be made clear while further improving the accuracy and comparability of the slice observation results. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0022] Figure 1 It is a schematic diagram of the overall structure of a lung tissue specimen fixing device capable of adjusting and displaying perfusion pressure according to the first embodiment of the present invention.

[0023] Figure 2 It is a flowchart of a lung tissue specimen fixing method capable of adjusting and displaying perfusion pressure according to a first embodiment of the present invention.

[0024] In the figure: 10-fixed container, 20-sealing cover, 21-first connecting pipe, 22-pipe mouth 1, 23-pipe mouth 2, 24-second connecting pipe, 25-pipe mouth 3, 26-pipe mouth 4, 30-pressure linkage cylinder, 31-first pressure linkage piston, 32-fixed liquid chamber, 33-air chamber, 40-pressure regulator, 41-second pressure linkage piston, 42-piston connecting rod, 43-pressure regulating stud, 44-nut limiting clamp, 45-pressure regulating nut, 46-piston limiting protrusion, 47-fixing groove, 48-first air chamber, 49-second air chamber, 50-U-type pressure gauge, 60-air pressure buffer, 411-fixed plate. DETAILED DESCRIPTION

[0025] Embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0026] First embodiment:

[0027] See also Figure 1 , Figure 1 It is a schematic diagram of the overall structure of a lung tissue specimen fixing device capable of adjusting and displaying perfusion pressure according to a first embodiment of the present invention. The present invention provides a lung tissue specimen fixing device capable of adjusting and displaying perfusion pressure, comprising a fixing container 10, a pressure linkage cylinder 30, a U-shaped pressure gauge 50, an air pressure buffer 60 and a pressure regulator 40.

[0028] In this embodiment, by using the fixing container 10, the pressure linkage cylinder 30, the U-shaped pressure gauge 50, the air pressure buffer 60 and the pressure regulator 40 in coordination, the pressure of the lung tissue can be monitored in real time during the process of passively absorbing the fixing liquid, and the pressure can be maintained under the functional residual capacity pressure condition. In addition, a negative pressure compensation circuit is designed so that the U-shaped pressure gauge 50 can accurately detect the pressure value of the lung tissue while avoiding the potential damage to the lung tissue caused by the reverse force of the detection liquid in the U-shaped pressure gauge 50. This can achieve better fixation of the lung tissue to form a specimen while avoiding the structural damage of the tissue caused by the fixing liquid pressure exceeding the bearing range of the lung tissue through pressure monitoring. By monitoring and regulating the pressure, the lung tissue can be in a better natural expansion state for lung pathology observation reported in the literature, and specimens of different individuals can be at the same pressure level. This can make the microscopic structure of the lung tissue slice clear while further improving the accuracy and comparability of the slice observation results.

[0029] Among them, a first connecting tube 21 and a second connecting tube 24 are extended into the fixed container 10, the first connecting tube 21 is connected to the pressure linkage cylinder 30, the second connecting tube 24 is connected to the pressure regulator 40, the U-shaped pressure gauge 50 is connected to the pressure linkage cylinder 30, and is located on the side of the pressure linkage cylinder 30 away from the first connecting tube 21, the air pressure buffer 60 is respectively connected to the U-shaped pressure gauge 50 and the pressure regulator 40, and the air pressure buffer 60 is located between the U-shaped pressure gauge 50 and the pressure regulator 40.

[0030] Secondly, a sealing cover 20 is disposed above the fixed container 10 , and the sealing cover 20 is used to seal the inner space of the fixed container 10 .

[0031] Again, a first pressure-linked piston 31 is provided in the pressure-linked cylinder 30 , and the first pressure-linked piston 31 divides the internal space of the pressure-linked cylinder 30 into two left and right chambers. The left chamber is a fixed liquid chamber 32 , and the right chamber is an air chamber 33 .

[0032] At the same time, a fixing groove 47 is provided on the outside of the pressure regulator 40, and the pressure regulator 40 is fixed to the outside of the fixing plate 411 through the fixing groove 47. A second pressure-linked piston 41 is provided in the pressure regulator 40, and the second pressure-linked piston 41 divides the internal space of the pressure regulator 40 into two left and right chambers. The chamber on the left is the first air chamber 48, and the chamber on the right is the second air chamber 49.

[0033] In addition, a piston limiting protrusion 46 is provided in the pressure regulator 40 , and the piston limiting protrusion 46 is used to limit the extreme position of the second pressure linkage piston 41 .

[0034] In addition, a piston connecting rod 42, a pressure adjusting stud 43 and a limit piece are arranged outside the second pressure-linked piston 41. The piston connecting rod 42 is arranged above the second pressure-linked piston 41, and the pressure adjusting stud 43 is arranged on the side of the piston connecting rod 42 away from the second pressure-linked piston 41. The limit piece is used to limit and fix the position of the pressure adjusting stud 43. When the second pressure-linked piston 41 moves laterally in the pressure regulator 40, the piston connecting rod 42 will move laterally with the second pressure-linked piston 41, thereby driving the pressure adjusting stud 43 to move laterally outside the fixing plate 411.

[0035] Finally, the limiting component includes a nut limiting clip 44 and a pressure adjusting nut 45. The nut limiting clip 44 is arranged on the fixing plate 411, and the pressure adjusting stud 43 passes through the nut limiting clip 44. The pressure adjusting nut 45 is detachably connected to the nut limiting clip 44, abuts against the pressure adjusting stud 43, and passes through the nut limiting clip 44. When the second pressure linkage piston 41 no longer moves laterally, the pressure adjusting stud 43 no longer continues to move laterally outside the fixing plate 411. Afterwards, the pressure adjusting bolt is gradually screwed into the nut limiting clip 44, so that the position of the pressure adjusting stud 43 is limited and fixed, and then the position of the second pressure linkage piston 41 is finally limited and fixed.

[0036] When using the lung tissue specimen fixing device of this embodiment that can adjust and display the perfusion pressure, the complete and leak-free lung tissue is ligated and fixed to the pipe mouth 23 of the first connecting tube 21, and the sealing cover 20 is tightly closed to make the fixing container 10 in a sealed state. Then, the pipe mouth 3 25 of the second connecting tube 24 is connected to the connecting port 1 of the pressure regulator 40 by a pipeline, and the pressure adjusting nut 45 is rotated to compress the first air chamber 48. The air pressure compresses the lung tissue in the fixing container 10 and discharges the gas in the lung.

[0037] Afterwards, the pipe mouth 22 of the first connecting pipe 21 is connected to the connecting port 1 of the pressure linkage cylinder 30 by a pipeline, and before the connection, the pipe cavity between the lung tissue and the fixing liquid chamber 32 is filled with fixing liquid, and then, the connecting port 2 of the pressure linkage cylinder 30 and the connecting port 1 of the U-shaped pressure gauge 50 are connected by a pipeline, and the connecting port 2 of the pressure regulator 40 is connected to the connecting port 1 of the air pressure buffer 60, and the connecting port 2 of the air pressure buffer 60 is connected to the connecting port 2 of the U-shaped pressure gauge 50.

[0038] Then, the pressure regulating nut 45 is rotated to expand the air chamber 33, so that negative pressure is generated between the fixed container 10 and the outside of the lung. The negative pressure drives the lung tissue to expand, and while the lung tissue expands, the fixing liquid in the pipeline is absorbed. While the fixing liquid is absorbed, the reduction of the fixing liquid in the fixing liquid chamber 32 causes the first pressure-linked piston 31 to move toward the fixing liquid chamber 32. At this time, the expansion of the air chamber 33 generates negative pressure, and the negative pressure causes the liquid level on one side of the U-shaped pressure gauge 50 to rise and the liquid level on the other side to drop. The pressure on the lung tissue is obtained by reading the difference between the two liquid levels.

[0039] In summary, through the coordinated use of the fixing container 10, the pressure linkage cylinder 30, the U-shaped pressure gauge 50, the air pressure buffer 60 and the pressure regulator 40, the pressure of the lung tissue can be monitored in real time during the process of passively absorbing the fixing liquid, and the pressure can be maintained under the functional residual capacity pressure condition. In addition, a negative pressure compensation circuit is designed so that the U-shaped pressure gauge 50 can accurately detect the pressure value of the lung tissue while avoiding the potential damage to the lung tissue caused by the reverse force of the detection liquid in the U-shaped pressure gauge 50, thereby achieving better fixation of the lung tissue to form a specimen while avoiding the structural damage of the tissue caused by the fixing liquid pressure exceeding the bearing range of the lung tissue through pressure monitoring. Through pressure monitoring and regulation, the lung tissue can be in a better natural expansion state for lung pathology observation reported in the literature, and specimens of different individuals can be at the same pressure level, which can make the microscopic structure of the lung tissue slice clear and further improve the accuracy and comparability of the slice observation results.

[0040] Third embodiment:

[0041] Based on the second embodiment, please refer to Figure 2 , Figure 2 1 is a flowchart of a lung tissue specimen fixing method capable of adjusting and displaying perfusion pressure according to a first embodiment of the present invention. The present invention also provides a lung tissue specimen fixing method capable of adjusting and displaying perfusion pressure, comprising the following steps:

[0042] S101, ligating and fixing the intact lung tissue without leakage to the second tube opening 23 of the first connecting tube 21, and closing the sealing cover 20 to make the fixed container 10 in a sealed state.

[0043] S102, connect the pipe port 3 25 of the second connecting pipe 24 to the connecting port 1 of the pressure regulator 40 with a pipe, rotate the pressure regulating nut 45, compress the first air chamber 48, and the air pressure compresses the lung tissue in the fixed container 10 and discharges the gas in the lung;

[0044] S103, then, connecting the pipe opening 22 of the first connecting pipe 21 and the connecting opening 1 of the pressure linkage cylinder 30 with the pipe, and before the connection, filling the pipe cavity between the lung tissue and the fixing liquid chamber 32 with fixing liquid;

[0045] S104, then, connect the second communication port of the pressure linkage cylinder 30 and the first communication port of the U-shaped pressure gauge 50 with the pipeline, connect the second communication port of the pressure regulator 40 to the first communication port of the air pressure buffer 60, and connect the second communication port of the air pressure buffer 60 to the second communication port of the U-shaped pressure gauge 50;

[0046] S105, rotating the pressure regulating nut 45 to expand the air chamber 33, so that negative pressure is generated between the fixing container 10 and the outside of the lung, and the negative pressure drives the lung tissue to expand, and while the lung tissue expands, the fixing liquid in the pipeline is absorbed;

[0047] S106, while the fixing liquid is being sucked, the reduction of the fixing liquid in the fixing liquid chamber 32 causes the first pressure-linked piston 31 to move toward the fixing liquid chamber 32;

[0048] S107. At this time, the air chamber 33 expands to generate negative pressure. The negative pressure causes the liquid level on one side of the U-shaped pressure gauge 50 to rise and the liquid level on the other side to drop. The pressure on the lung tissue is obtained by reading the difference between the two liquid levels.

[0049] Specifically, negative pressure is generated by expanding the air chamber 33. The negative pressure causes the liquid level on one side of the U-shaped pressure gauge 50 to rise and the liquid level on the other side to drop, and the pressure on the lung tissue is obtained by reading the difference between the two liquid levels. At the same time, the reaction force generated by the gravity of the liquid column in the U-shaped pressure gauge 50 will act in the opposite direction on the lung tissue, causing potential damage to the lung tissue. Therefore, pressure compensation is required to prevent the reaction force of the U-shaped pressure gauge 50, that is, the pressure linkage piston is designed in the pressure regulator 40 so that the first air chamber 48 generates a negative pressure while the second air chamber 49 generates the same positive pressure. The positive pressure is used to compensate for the pressure lost on one side of the second connecting port of the U-shaped pressure gauge 50, wherein the compensating positive pressure generated by the second air chamber 49 cannot be equal to the pressure lost on the other side, so as to avoid inaccurate pressure readings on the lung tissue. In addition, the air pressure buffer 60 is arranged between the U-shaped pressure gauge 50 and the pressure regulator 40, and the pressure on one side of the second connecting port of the U-shaped pressure gauge 50 is slightly lower than the pressure on the other side. At the same time, while the liquid column in the U-shaped pressure gauge 50 has a downward inclination, a certain supporting force is given to prevent the reaction force of the liquid column of the U-shaped pressure gauge 50 from causing potential damage to the lung tissue.

[0050] What is disclosed above is only one or more preferred embodiments of the present application, and cannot be used to limit the scope of rights of the present application. Ordinary technicians in this field can understand that all or part of the processes of implementing the above embodiments and equivalent changes made according to the claims of the present application are still within the scope covered by the present application.

Claims

1. A lung tissue specimen fixing device capable of adjusting and displaying perfusion pressure, characterized in that: It includes a fixed container, a pressure linkage cylinder, a U-shaped pressure gauge, a gas pressure buffer and a pressure regulator. A first connecting pipe and a second connecting pipe extend into the fixed container. The first connecting pipe is connected to the pressure linkage cylinder, and the second connecting pipe is connected to the pressure regulator. The U-shaped pressure gauge is connected to the pressure linkage cylinder and is located on the side of the pressure linkage cylinder away from the first connecting pipe. The gas pressure buffer is connected to the U-shaped pressure gauge and the pressure regulator respectively, and the gas pressure buffer is located between the U-shaped pressure gauge and the pressure regulator.

2. The lung tissue specimen fixing device capable of adjusting and displaying perfusion pressure as claimed in claim 1, characterized in that: A first pressure-linked piston is arranged in the pressure-linked cylinder. The first pressure-linked piston divides the internal space of the pressure-linked cylinder into two left and right chambers. The left chamber is a fixed liquid chamber, and the right chamber is an air chamber.

3. The lung tissue specimen fixing device capable of adjusting and displaying perfusion pressure as claimed in claim 1, characterized in that: A fixing groove is arranged on the outer side of the pressure regulator, and the pressure regulator is fixed outside the fixing plate through the fixing groove.

4. The lung tissue specimen fixing device capable of adjusting and displaying perfusion pressure as claimed in claim 3, characterized in that: A second pressure-linked piston is provided in the pressure regulator, and the second pressure-linked piston divides the internal space of the pressure regulator into two left and right chambers, the left chamber is the first air chamber, and the right chamber is the second air chamber.

5. The lung tissue specimen fixing device capable of adjusting and displaying perfusion pressure as claimed in claim 4, characterized in that: A piston limiting protrusion is arranged in the pressure regulator, and the piston limiting protrusion is used to limit the extreme position of the second pressure linkage piston.

6. The lung tissue specimen fixing device capable of adjusting and displaying perfusion pressure as claimed in claim 5, characterized in that: A piston connecting rod, a pressure adjusting stud and a limiter are arranged outside the second pressure-linked piston. The piston connecting rod is arranged above the second pressure-linked piston, and the pressure adjusting stud is arranged on the side of the piston connecting rod away from the second pressure-linked piston. The limiter is used to limit and fix the position of the pressure adjusting stud.

7. A lung tissue specimen fixing method capable of adjusting and displaying perfusion pressure, applied to a lung tissue specimen fixing device capable of adjusting and displaying perfusion pressure as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: The intact lung tissue without leakage is ligated and fixed to the second tube opening of the first connecting tube, and the sealing cover is tightly closed to make the fixed container in a sealed state; Then, the pipe port 3 of the second connecting pipe is connected to the connecting port 1 of the pressure regulator by a pipe, and the pressure regulating nut is turned to compress the first air chamber, so that the air pressure compresses the lung tissue in the fixed container and discharges the gas in the lung; Afterwards, the pipe opening of the first connecting pipe is connected to the connecting opening of the pressure linkage cylinder by the pipe, and before the connection, the pipe cavity between the lung tissue and the fixing liquid chamber is filled with fixing liquid; Then, the pipeline is used to connect the second communication port of the pressure linkage cylinder and the first communication port of the U-shaped pressure gauge, and the second communication port of the pressure regulator is connected to the first communication port of the air pressure buffer, and the second communication port of the air pressure buffer is connected to the second communication port of the U-shaped pressure gauge; Turning the pressure regulating nut to expand the air chamber, so that negative pressure is generated between the fixed container and the outside of the lung, the negative pressure drives the lung tissue to expand, and while the lung tissue expands, the fixing liquid in the pipeline is absorbed; While the fixing liquid is being sucked, the reduction of the fixing liquid in the fixing liquid chamber causes the first pressure-linked piston to move toward the fixing liquid chamber; At this time, the expansion of the air chamber generates negative pressure, which causes the liquid level on one side of the U-shaped pressure gauge to rise and the liquid level on the other side to drop, and the pressure on the lung tissue is obtained by reading the difference between the two liquid levels.

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