Pressure measuring device, sheath having same and perfusion aspiration system

Abstract

A pressure measuring device, a sheath having same and a perfusion aspiration system. The pressure measuring device comprises a housing (2) and a pressure measuring assembly (5). The housing (2) is provided with a pressure measuring cavity (21) and a mounting cavity (20). The pressure measuring cavity (21) is provided with an air inlet (22) used for communicating with a sheath pressure measuring connection opening and a vent hole (23) used for communicating with the outside, a switch being arranged at the vent hole (23). The pressure measuring assembly (5) is arranged in the mounting cavity (20), and the pressure measuring assembly (5) comprises a gauge pressure sensor, a voltage adjustment circuit, an operational amplifier circuit and a conversion circuit, the gauge pressure sensor, the voltage adjustment circuit and the operational amplifier circuit being electrically connected to the conversion circuit, and the gauge pressure sensor being used for converting a pressure signal of the inside of the pressure measuring cavity (21) into a voltage signal.

Description

Pressure detection device, sheath tube and perfusion suction system having the same Technical Field

[0001] The present invention relates to the field of sheath tubes, and in particular to a sheath tube device capable of measuring pressure and a micro-pressure sensor used for the sheath tube. Background Art

[0002] During conventional flexible ureteroscopic lithotripsy, stone dust and hematuria within the renal pelvis can blur vision, necessitating irrigation with flushing fluid to maintain a clear field of vision. However, due to excessive irrigation and poor reflux, renal pelvic pressure can significantly increase. This can lead to infected urine, bacteria, and endotoxins entering the blood and lymphatic circulation, leading to fever, systemic inflammatory response syndrome, and even fatal urosepsis after surgery. To prevent severe infection caused by excessive renal pelvic pressure during flexible ureteroscopic lithotripsy, intraoperative control of renal pelvic pressure within a safe range is essential. Furthermore, feedback adjustment of the irrigation rate and / or the level of negative pressure suction based on intraoperative renal pelvic pressure is necessary. The ability of the pressure measurement method to accurately and in real time measure renal pelvic pressure is crucial for ensuring the performance of the pressure measurement and control system and the safety of the surgical procedure. There are three traditional pressure measurement methods: 1. The first method measures pressure by installing a pressure sensor in the irrigation line. Normal saline is passed through a silicone membrane for monitoring. However, this method only reflects the irrigation pressure and is not the most direct way to monitor renal pressure. 2. The second pressure measurement method uses a sensor to directly monitor intrarenal pressure. The sensor is installed inside the main control unit and connected to the introducer sheath via tubing, thereby enabling intrarenal pressure monitoring. This method monitors and provides feedback based on the height difference in the fluid level within a long tubing line. However, the sensor's range is too large compared to the intrarenal pressure, resulting in low accuracy. 3. The third method also monitors intrarenal pressure using an external sensor with a smaller range. This sensor is connected to the introducer sheath via tubing, which is filled with fluid. Pressure is monitored and provided by infusion or aspiration. However, this method also suffers from the problem of long tubing, and the fluid level fluctuates with position, affecting pressure deviation. All three methods suffer from the long tubing from the renal pelvis to the sensor, i.e., the pressure measuring chamber, which can lead to large measurement errors. Furthermore, the infusion and aspiration system is bulky and requires numerous cables and tubing. The physician must simultaneously operate the endoscope, the main unit, aspiration, and infusion, inevitably causing accidental collisions with the pressure measuring line. This can cause sudden pressure fluctuations, further leading to pressure measurement errors. Therefore, there are the above technical problems when the sensor is placed in the perfusion line, perfusion host or externally. At present, there is also a method of directly embedding the sensor into the distal end of the endoscope or the distal end of the sheath. In this way, the pressure is directly monitored after the endoscope or sheath enters the body cavity. This installation method directly locates the renal pelvis and the detection error will be smaller. However, in actual operation, the perfusion and suction system is used for laser lithotripsy. The high temperature generated during the laser lithotripsy process will damage the tissue. Therefore, a perfusion and suction cycle is required to reduce the temperature in the body cavity and maintain constant temperature and pressure. However, the laser lithotripsy process will cause instantaneous high pressure, which cannot reflect the actual pressure in the cavity. At present, it generally takes 2-5 seconds from the sensor to the display of the pressure value. When the instantaneous high pressure is displayed, the pressure in the cavity has stabilized. The pressure output value at this time cannot truly reflect the actual pressure in the cavity and will miscontrol the perfusion and suction device. Therefore, placing the sensor in the cavity has more disadvantages. Summary of the Invention

[0003] In a first aspect, the present invention provides a sheath tube with a pressure measurement function, the sheath tube comprising a sheath tube body, the sheath tube body having a main channel extending from a proximal end to a distal end and a pressure measurement channel, the proximal end of the pressure measurement channel being provided with an interface, the sheath tube further comprising a pressure detection device, the pressure detection device comprising:

[0004] A housing having a pressure measuring cavity and a mounting cavity, wherein the pressure measuring cavity has an air inlet for communicating with the sheath pressure measuring interface and a vent for communicating with the outside world, and a switch is provided at the vent;

[0005] A pressure detection assembly is disposed in the mounting cavity and includes a gauge pressure sensor, a voltage adjustment circuit, an operational amplifier circuit, and a conversion circuit. The gauge pressure sensor, the voltage adjustment circuit, the operational amplifier circuit, and the conversion circuit are electrically connected. The gauge pressure sensor converts the pressure signal in the pressure measuring cavity into a voltage signal.

[0006] The voltage adjustment circuit is used to increase the voltage difference of the voltage signal, and the operational amplifier circuit multiplies the increased voltage difference; the conversion circuit is used to convert the multiplied voltage signal into a pressure value;

[0007] The aerogel insulation is encapsulated on the surface of the pressure detection component to transmit pressure.

[0008] In some embodiments, the gauge pressure sensor has an input voltage positive electrode (+vin), an input voltage negative electrode GND (-vin), an analog signal output voltage positive electrode (+out), and an analog signal output voltage negative electrode (-out); the voltage adjustment circuit includes at least a first resistor (R1) and a second resistor (R3), the first resistor (R1) is connected in parallel between the input voltage positive electrode (+vin) and the analog signal output voltage positive electrode (+out), and the first resistor (R3) is connected in parallel between the input voltage negative electrode GND (-vin) and the analog signal output voltage negative electrode (-out).

[0009] In some embodiments, the op amp circuit is a GS8332 precision op amp chip that amplifies the voltage difference by 100 times. In some embodiments, the resistance of the first resistor (R1) and the second resistor (R3) is 100K. In some embodiments, the conversion circuit is a single-chip microcontroller (MCU) STM32F103C8T6.

[0010] In some embodiments, the shell includes: a base, a pressure measuring tube for forming a pressure measuring chamber is provided on the base, an air inlet is provided at one end of the pressure measuring tube, and a vent is formed at the other end, and the pressure measuring tube has an outlet for the outflow of gas in the pressure measuring tube; an upper cover, the upper cover is arranged above the base; a PCB board, the PCB board is located inside the base and fixed on the upper cover, the PCB board integrates a pressure detection component and a control circuit, the pressure detection component is arranged directly at the outlet and is sealed by an aerogel insulating member; a control button, the control button is arranged on the shell and is communicatively connected to the control circuit; a connecting cable, the connecting cable is connected to the conversion circuit to output a pressure test value.

[0011] In a second aspect, the present invention provides a method for detecting the aforementioned sheath device, the method comprising the following steps:

[0012] Step 1) Conversion stage: The gauge pressure sensor converts the pressure signal into a μV-level voltage; Step 2) Increasing the voltage difference stage: By connecting a first resistor (R1) in parallel between the positive pole of the input voltage (+vin) and the positive pole of the analog signal output voltage (+out), and connecting a second resistor (R3) in parallel between the negative pole of the input voltage GND (-vin) and the negative pole of the analog signal output voltage (-out), the voltage difference is increased to the mV level to meet the minimum voltage difference requirement of the op amp circuit; Step 3) Op amp stage: Through the op amp circuit, the voltage difference is amplified 100 times to the V (volt) level; the range is (0.5-3.0V); Step 4) Conversion stage: The voltage difference in step 3) is converted into a pressure value output through the conversion circuit; Step 5) Acquisition stage: The gauge pressure sensor performs multiple acquisitions, and the microcontroller removes the extreme values ​​and calculates the average to convert it into a pressure value output.

[0013] In a third aspect, the present invention provides a pressure detection device, which adopts the pressure detection device described above.

[0014] In a fourth aspect, the present invention provides an intelligent constant pressure controlled perfusion and suction system, the system comprising

[0015] The sheath tube mentioned above further has a suction channel in the sheath tube body;

[0016] an endoscope, wherein the endoscope is inserted into the sheath tube and a liquid delivery channel is formed in the endoscope;

[0017] a perfusion device, the perfusion device being in communication with the liquid delivery channel for injecting perfusion liquid into the body cavity;

[0018] A suction device, the suction device is connected to the suction channel and is used to extract liquid from the human body cavity, and the irrigation device cooperates with the suction device to maintain the cavity at a suitable pressure;

[0019] The main control machine is in communication with the conversion circuit, the perfusion device and the suction device, and controls the flow rate and pressure of the perfusion device and the suction device according to the pressure value output by the conversion circuit.

[0020] In some embodiments, the pressure detection assembly further includes a control circuit, which is connected to a main control machine to control the infusion device and the suction device.

[0021] In a fifth aspect, the present invention provides a method for intelligently controlling constant pressure in a perfusion and suction system, the method comprising the following steps:

[0022] Step 1) Preset a maximum warning pressure value, a minimum warning pressure value, a pressure control value, and an infusion flow rate gear; Step 2) A main control machine controls the delivery of infusion fluid to the infusion device and the withdrawal of fluid from the suction device, and collects intracavitary pressure and negative pressure suction pressure; Step 3) A pressure detection device collects intracavitary pressure and transmits it to the main control machine. The main control machine dynamically adjusts the infusion and suction states based on the real-time monitored pressure value and the data change trend of the pressure value, so that the current intracavitary pressure is balanced at the pressure control value, thereby achieving a balanced state of infusion and suction. The infusion parameters include the infusion flow rate gear, and the suction parameters include the opening of the pressure relief valve and the suction pressure threshold;

[0023] The main control machine pressure regulation mode includes a coarse adjustment mode, a fine adjustment mode and a mixed adjustment mode. The coarse adjustment mode is for the case where the pressure in the cavity is in an extreme situation, the fine adjustment mode is for the case where the pressure difference between the cavity pressure and the pressure control value is small, and the mixed adjustment mode is for the case where the pressure in the cavity does not reach an extreme situation but the deviation value is large.

[0024] In some embodiments, when the pressure difference between the cavity pressure and the pressure control value is in an extreme situation, for example, exceeding ±20 mmHg, the coarse adjustment mode is started; when the pressure difference exceeds ±3 mmHg and is within ±8 mmHg, the fine adjustment mode is started; when the pressure difference is detected to be exceeding ±8 mmHg and within ±20 mmHg, the mixed adjustment mode is started.

[0025] In some embodiments, the coarse adjustment mode includes the following steps: when the pressure value in the body cavity exceeds the highest warning line, the main control machine controls the reduction of the perfusion flow rate gear and controls the suction pressure threshold so that the suction flow rate is greater than the perfusion flow rate. When the pressure difference in the cavity pressure exceeds the lowest warning line, the perfusion process gear will be increased, the pressure relief valve will be opened, and the suction pressure threshold will be adjusted to the threshold value under the stable state to achieve a rapid balance effect, so that the pressure in the cavity can be removed from the extreme state as soon as possible.

[0026] In some embodiments, the fine adjustment mode includes the following steps: maintaining the perfusion gear in operation, keeping the pressure relief valve closed, and performing pressure regulation by finely adjusting the suction pressure threshold.

[0027] In some embodiments, when the pressure difference exceeds -3 mmHg and is within -8 mmHg, the perfusion flow rate gear is kept unchanged, the pressure relief valve is kept closed, the perfusion maintains the current operation, and the uploaded data change trend is observed. If it is in an upward stage, the suction pressure threshold is increased. If it is in a downward trend, the suction pressure threshold is reduced and the reduction amplitude is greater than the amplitude of increasing the suction pressure threshold in the upward stage. In this way, during the data adjustment process, there is an overall trend to reduce the suction pressure threshold, and the pressurization effect is achieved in a fine-tuning manner; when the pressure difference exceeds 3 mmHg and is within 8 mmHg, the perfusion maintains the current gear operation, and the uploaded data change trend is observed. If it is in an upward stage, the "suction pressure threshold" is increased. If it is in a downward trend, the "suction pressure threshold" is reduced and the reduction amplitude is less than the amplitude of increasing the suction pressure threshold in the upward stage. During the data adjustment process, there is an overall trend to increase the "suction pressure threshold" to achieve a decompression effect.

[0028] In some embodiments, the hybrid regulation mode includes the following steps: by combining the adjustment of the perfusion flow gear, the pressure relief valve and the suction pressure threshold, the fine adjustment of the perfusion flow, the fine adjustment of the pressure relief valve and the fine adjustment of the suction pressure threshold are combined to jointly act on the intracavitary pressure to achieve the effect of increasing or decreasing pressure.

[0029] In some embodiments, when it is detected that the pressure difference exceeds 8 mmHg and is within 20 mmHg, the perfusion flow rate is appropriately reduced, and the change trend of the uploaded data is observed. If it is in an upward stage, the suction pressure threshold is increased. If it is in a downward trend, the "suction pressure threshold" is reduced, and the reduction amplitude is smaller than the amplitude of the increase of the suction pressure threshold in the upward stage; in this way, during the data adjustment process, there is an overall trend of increasing the "suction pressure threshold" to achieve a decompression effect; when it is detected that the pressure difference is lower than -8 mmHg and within -20 mmHg, the perfusion flow rate maintains the current operation, the pressure relief valve is opened in stages, and the change trend of the uploaded data is observed. If it is in an upward stage, the suction pressure threshold is increased. If it is in a downward trend, the "suction pressure threshold" is reduced, and the reduction amplitude is larger than the amplitude of the increase of the suction pressure threshold in the upward stage; in this way, during the data adjustment process, there is an overall trend of reducing the "suction pressure threshold" to achieve a pressurization effect;

[0030] In some embodiments, the adjustment range of the suction pressure threshold increases as the pressure difference between the intracavity pressure and the pressure control value increases.

[0031] The present invention installs the pressure detection device at the proximal end of the sheath tube, which first solves the problem of the traditional pressure detection pipeline being too long and having high errors. Secondly, the sheath tube is located in the cavity during actual operation, and the doctor will not accidentally touch the sheath tube, thus avoiding the pressure detection error caused by the doctor accidentally bumping into the pressure measurement pipeline. Finally, the present invention places the pressure detection device at the proximal end of the sheath tube, which will not detect the instantaneous high pressure caused by laser lithotripsy, and the stable pressure in the cavity is detected with small detection error and high accuracy. The sheath tube device provided by the present invention combines the sheath tube and the pressure detection component in a design, based on the relationship between the voltage and pressure of the gauge pressure sensor, and after passing through the voltage adjustment circuit and the operational amplifier circuit, it is converted by the single-chip microcomputer to convert the voltage signal into a specific pressure value, thereby realizing real-time monitoring of the intracavity pressure with high detection accuracy and high sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG1 is a schematic structural diagram of a sheath tube provided by the present invention;

[0033] Figures 2-6 are schematic structural diagrams of a pressure detection device provided by the present invention;

[0034] FIG7 is a schematic diagram of the working principle of the pressure detection device provided by the present invention;

[0035] FIG8 is a schematic structural diagram of a pressure detection assembly provided by the present invention;

[0036] FIG9 is a schematic structural diagram of the sheath tube body provided by the present invention;

[0037] FIG10 is a schematic structural diagram of the perfusion system provided by the present invention;

[0038] FIG11 is a circuit diagram of a gauge pressure sensor provided by the present invention;

[0039] FIG12 is a schematic diagram of a voltage regulation circuit provided by the present invention;

[0040] FIG13 is a schematic diagram of an operational amplifier circuit provided by the present invention;

[0041] 14-16 are process curve diagrams of the control method provided by the present invention. DETAILED DESCRIPTION

[0042] In the description of the present invention, it should be understood that the terms "upper," "lower," "front," "back," "left," "right," "inner," "outer," "near," "far," and the like, indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They do not indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific direction, and therefore should not be construed as limitations on the present invention. Furthermore, features defined as "first" or "second" may explicitly or implicitly include one or more of such features.

[0043] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances. Example 1

[0044] Referring to Figures 1-9, an embodiment of the present invention provides a sheath with a pressure measurement function. The sheath includes a sheath body 1 and a pressure detection device. The sheath body has a main channel 11 extending from the proximal end to the distal end and a pressure measurement channel 12. The main channel 11 is used for instrument placement, perfusion, and suction. The proximal end of the pressure measurement channel 12 is provided with an interface 121. The pressure detection device is assembled at the interface to detect the pressure within the pressure measurement cavity. Thus, the present invention installs the pressure detection device at the proximal end of the sheath, solving the problem of high error caused by the excessive length of the traditional pressure detection pipeline. In actual operation, the sheath is located within the cavity, so the doctor will not accidentally touch the sheath, thus avoiding pressure detection errors caused by the doctor accidentally hitting the pressure measurement pipeline. This embodiment places the pressure detection device at the proximal end of the sheath, preventing the detection of transient high pressure caused by laser lithotripsy. Instead, it detects the stable pressure within the cavity, resulting in low detection error and high accuracy. Current pressure detection devices have technical problems such as difficult assembly, inaccurate detection, large errors, and low sensitivity. In particular, when a gauge pressure sensor is used to detect the pressure in the renal pelvis, since the directly monitored pressure is a μV-level voltage, if it is directly amplified by an operational amplifier circuit, this μV-level voltage is difficult to meet the amplification requirements of the operational amplifier circuit, and during the amplification process, the voltage difference must increase in proportion to the pressure. Based on this, the pressure detection device provided in this embodiment includes a housing 2, an aerogel insulator 3, and a pressure detection assembly 5. The housing 2 has a pressure measurement chamber 21 and an installation chamber 20. The pressure measurement chamber 21 has an air inlet 22 for communicating with the sheath pressure measurement interface and a vent 23 for communicating with the outside world. The vent 23 is provided with a switch. The pressure detection assembly 5 is disposed in the installation chamber 22. The pressure measurement chamber 21 is aligned with the pressure detection assembly 5 to form an outlet 210. The outlet 210 is sealed by the aerogel insulator 3. The aerogel insulator 3 is used to transmit the pressure of the pressure measurement chamber 21 to the pressure detection assembly 5.

[0045] As shown in Figure 7, the A end of the vent 23 is connected to a switch. When it is opened, it can connect the pressure detection device to the atmosphere for zero calibration; when it is closed, pressure can be measured. The B end of the air inlet 22 is connected to the interface 121 of the sheath body; after zeroing, the switch at the A end is closed. When pressure comes from the B end, the pressure passes through the polycarbonate insulating gel and is converted into a signal output by the gauge pressure sensor; the switch is opened to connect the air and the air inlet. The subsequent pressure measurement is based on the current pressure. Each sensor has certain differences. It is calibrated using software and the calibration data is saved in the microcontroller. The calibration data is still saved when the power is off; therefore, each sensor only needs to be calibrated once.

[0046] The pressure detection assembly provided in this embodiment includes a gauge pressure sensor, a voltage adjustment circuit, an operational amplifier circuit, and a conversion circuit. The gauge pressure sensor, voltage adjustment circuit, operational amplifier circuit, and conversion circuit are electrically connected. The gauge pressure sensor converts the pressure signal within the pressure measuring chamber into a voltage signal. The voltage adjustment circuit increases the voltage difference of the voltage signal, and the operational amplifier circuit amplifies the increased voltage difference. The conversion circuit converts the amplified voltage signal into a pressure value. In this embodiment, the pressure signal is converted from pressure to voltage, amplified by pull-up and pull-down resistors, and finally further amplified by the operational amplifier circuit before being transmitted to a microcontroller for analog-to-digital conversion to obtain the specific pressure value.

[0047] Figure 11 shows the detection circuit within the gauge pressure sensor. This circuit's primary function is to convert the pressure signal into a voltage signal with a conversion relationship of 5µV / V / mmHg. Directly acquiring this signal using 12-bit A / D conversion would require amplification because the voltage difference between the voltage and pressure is too small. The microcontroller's 12-bit A / D acquisition accuracy is 3.3V / 4096 = 8.056mV, far exceeding the pressure-voltage relationship of the gauge pressure sensor (5µV / V / mmHg). Therefore, this implementation increases the voltage difference between the analog signal output terminal (V+) and the analog signal output terminal (V-), while maintaining a linear relationship between voltage and pressure.

[0048] The gauge pressure sensor has a positive input voltage (+vin), a negative input voltage (GND) (-vin), a positive analog signal output voltage (+out), and a negative analog signal output voltage (-out). As shown in FIG12 , the voltage adjustment circuit includes a first resistor (R1) and a second resistor (R3). The first resistor (R1) is connected in parallel between the positive input voltage (+vin) and the positive analog signal output voltage (+out). R1 ​​is connected between V+ and VDD6V. This resistor is connected in parallel with the pull-up resistor inside the sensor. After the resistors are connected in parallel, the resistance decreases, and the voltage of V+ is greater than the sensor output voltage V+. The first resistor (R2) is connected in parallel between the negative input voltage (GND) (-vin) and the negative analog signal output voltage (-out). R3 is connected between V- and GND, and is connected in parallel with the pull-down resistor inside the sensor. The voltage of V- is smaller than the sensor voltage V-. This part of the circuit increases the voltage difference between V+ and V-, preparing for the next step of the operational amplifier.

[0049] As shown in Figure 13, in order to maintain the linear relationship between the sensor pressure and voltage, the GS8332 precision operational amplifier chip is used to amplify the voltage difference by 100 times.

[0050] Optionally, the operational amplifier circuit is a GS8332 precision operational amplifier chip, which amplifies the voltage difference by 100 times. The resistance value of the first resistor (R1) and the second resistor (R3) is 100K. The conversion circuit is a single-chip microcomputer stm32f103c8t6

[0051] The detection method of the present invention comprises the following steps:

[0052] Step 1) Conversion stage: The gauge pressure sensor converts the pressure signal into a μV voltage.

[0053] Step 2) Increase the voltage difference: Connect a first resistor (R1) in parallel between the positive input voltage (+vin) and the positive analog signal output voltage (+out), and a second resistor (R3) in parallel between the negative input voltage (-vin) and the negative analog signal output voltage (-out) to increase the voltage difference and meet the minimum voltage difference requirement of the op amp circuit.

[0054] Step 3) Operational amplifier stage: The voltage difference is amplified 100 times to the V (volt) level through the operational amplifier circuit;

[0055] Step 4) Conversion stage: The voltage difference in step 4) is converted into a pressure value output through a conversion circuit;

[0056] Step 5) Acquisition phase: The gauge pressure sensor collects data multiple times, and the microcontroller removes the extreme values ​​and calculates the average value to convert it into a pressure value output.

[0057] For example,

[0058] Part 1:

[0059] Please refer to Figure 11. The analog signal output terminal positive electrode V+ and the analog signal output terminal negative electrode V- are connected to R6, R7, R4, R6, R7, and R10, all of which are 10K. The voltage at C8 is VOUT. According to the op amp formula VOUT-(V+ / 2)=(V+ / 2)-(V-), we get VOUT=(V+)-(V-). Therefore, the function of this part is to calculate the voltage difference between the analog signal output terminal positive electrode V+ and the analog signal output terminal negative electrode V-.

[0060] Part II:

[0061] Please refer to Figure 12, R9=1k, R8=100K, mainly through these two resistors to amplify the voltage difference between V+ and V-. According to the relationship between R8 and R9, the voltage difference is amplified by 100 times, and the final output voltage range is 0.5V-3.0V, which is in line with the AD acquisition range of STM32F103C8T6.

[0062] The pressure detection device provided by this invention offers the following advantages over existing technologies: 1. Data can be saved after sensor calibration. 2. Calibration accuracy can be adjusted (by controlling pull-up and pull-down resistors). 3. Analog signals are converted into digital signals and transmitted to a host computer via a serial port by a single-chip microcontroller, increasing sensor compatibility. 4. The sensor module is independent, allowing for wider application scenarios.

[0063] In this embodiment, the shell includes a base 3, an upper cover 4, a PCB board 5, a control button 6 and a connecting cable 7; the base 1 is provided with a pressure measuring tube 21 for forming a pressure measuring chamber, and the pressure measuring tube 21 is provided with an air inlet 22 at one end and a vent 23 at the other end. The pressure measuring tube 21 has an outlet 210 for the outflow of gas in the pressure measuring tube; the upper cover 4 is provided above the base; the PCB board 5 is located inside the base and fixed on the upper cover, and the PCB board integrates a pressure detection component and a control circuit, and the pressure detection component is arranged at the outlet 210 and is sealed by an aerogel insulating member 3; the control button is provided on the shell and is communicatively connected to the control circuit; the connecting cable 7 is connected to the conversion circuit to output the pressure test value, and the connecting cable has an aviation connector 71.

[0064] Specifically, the PCB board, pressure detection assembly and control circuit are installed in the housing 50 . A through hole is formed on the housing and sealed by polycarbonate insulating gel. The through hole is arranged opposite to the outlet 210 .

[0065] In some embodiments, the pressure detection assembly further includes a control circuit, which is connected to a main control machine to control the infusion device and the suction device.

[0066] The sheath tube device provided by the present invention combines the sheath tube and the pressure detection component in a design. Based on the relationship between the voltage and pressure of the gauge pressure sensor, and after passing through the voltage adjustment circuit and the operational amplifier circuit, the voltage signal is converted into a specific pressure value through AD conversion, avoiding the pressure deviation caused by the long pipeline and ultimately realizing real-time monitoring of the intracavitary pressure. Example 2

[0067] Referring to FIG10 , this embodiment provides an intelligent constant pressure controlled perfusion and aspiration system, comprising the sheath described in Example 1, an endoscope 8, a perfusion device, a suction device, and a main control unit 100. The sheath further comprises a suction channel, which in this embodiment is the same channel as the main channel. The endoscope 8 is inserted into the sheath, forming a liquid delivery channel within the endoscope 8. The perfusion device 10 is connected to the liquid delivery channel for injecting perfusion fluid into the body cavity.

[0068] The suction device is used to suck the waste fluid and stones in the cavity through the sheath tube through the main machine under negative pressure, and collect the waste fluid and stones into the collector through the negative pressure suction tubes 2 and 1. The perfusion device cooperates with the suction device to maintain the cavity at a suitable pressure.

[0069] The perfusion device includes a liquid inlet pipe 101, a liquid storage tank 102 and a perfusion pump. The perfusion pump 103 is connected to the liquid storage bag through the liquid inlet pipe 101; the perfusion pump 103 is connected to the 8 liquid delivery channels of the endoscope through the liquid outlet pipe 103;

[0070] The suction device includes a suction pump, a first negative pressure suction tube 91, a suction container 93, a second negative pressure suction tube 92 and a pressure sensor. One end of the first negative pressure suction tube 91 is connected to the outer sheath tube 1, and the other end is connected to the suction container 93. One end of the second negative pressure suction 92 is connected to the suction container 93, and the other end is connected to the suction pump. The pressure sensor is used to detect the intracavitary pressure in the suction container 93. The suction container 93 is provided with a pressure relief valve.

[0071] The main control machine 100 is communicatively connected with the conversion circuit, the perfusion device and the suction device. The main control machine controls the flow rate and pressure of the perfusion device and the suction device according to the pressure value output by the conversion circuit. In this embodiment, the perfusion pump, the suction pump and the main control machine are integrated and installed. Optionally, the perfusion pump is a peristaltic pump and the suction pump is a diaphragm pump.

[0072] The pressure detection device provided in this embodiment is also provided with a control circuit, which is connected to the main control machine 100 via a cable connector 71. The single-chip microcomputer transmits the pressure value to the main control machine, and the main control machine adjusts the flow and pressure of the perfusion device and the suction device according to the pressure output value to adjust the pressure in the chamber.

[0073] The system also includes a display capable of displaying the pressure output value.

[0074] In one embodiment of the present invention, the present invention provides a constant voltage intelligent control method, which includes the following steps:

[0075] Step 1) The pressure of the pressure detection device is output to the main control machine, and the main control machine compares the pressure with the preset ideal pressure. If the pressure does not meet the ideal pressure requirement, the main control machine controls the perfusion and aspiration parameters, such as proportional pressure, temperature, and flow rate;

[0076] Step 2) The pressure detection device is provided with a control button, which can be used to directly control the perfusion device and the suction device to regulate the pressure in the body cavity.

[0077] In a preferred embodiment of the present invention, the suction device further includes a pressure sensor, which is used to detect the intracavity pressure in the suction container 93. The suction container 93 is provided with a pressure relief valve.

[0078] The main control machine controls the change of the suction pressure threshold. When the pressure of the suction container 93 is greater than the suction pressure threshold, the suction pump stops. When the pressure of the suction container is less than the suction pressure threshold and the current cavity pressure is greater than the "pressure control value -3mmHg", the suction pump is turned on. The pressure of the suction container is adjusted by changing the suction pressure threshold. The different pressures of the suction container lead to different suction flow rates. By adjusting the suction flow rate and the perfusion flow rate, a certain pressure is maintained in the cavity to achieve a dynamic balance between perfusion and suction.

[0079] The master controller further presets a maximum warning pressure value, a minimum warning pressure value, a pressure control value, and an infusion flow rate level. The "pressure control value" here refers to the desired pressure value or pressure range within the chamber, and the "warning pressure value" refers to the state where the pressure difference between the chamber pressure and the pressure control value exceeds this value. The pressure detection device monitors the chamber pressure every 0.25 seconds. If the chamber pressure is not within the "pressure control value ±8 mmHg," it indicates that the pressure is too high or too low compared to the "pressure control value," and the pressure difference is too large. In this case, coarse pressure adjustment is required, such as adjusting the infusion level and the pressure relief valve to quickly adjust the chamber pressure to approach or reach the pressure control value. However, when the chamber pressure is within the "pressure control value ±8 mmHg," the pressure difference between the chamber pressure and the pressure control value is small. Continued coarse adjustments, such as adjusting the infusion level or the pressure relief valve, can easily cause the chamber pressure to reach the other extreme, making it difficult to reach or reach the control value. In addition, the suction pressure of the suction pump of the suction device is relatively large. If the pressure is directly adjusted by the suction pump, it is also difficult to achieve the effect of fine adjustment. Based on this, the present invention fine-tunes the pressure threshold of the suction container; in summary, the present invention aims to obtain a dynamic balance of pressure in the cavity, and maintains the pressure in the cavity in a dynamic balance state of the pressure control value through a combination of coarse adjustment and fine adjustment.

[0080] The present invention provides a constant pressure control method for a perfusion and suction system, the method comprising the following steps:

[0081] Step 1) Preset the maximum warning pressure value, minimum warning pressure value, pressure control value, and perfusion flow rate gear;

[0082] Step 2) The main control unit controls the delivery of perfusion solution to the perfusion device and the suction of the suction device, and collects the intracavitary pressure and negative pressure suction pressure:

[0083] Step 3) The pressure detection device collects the pressure in the cavity and transmits it to the main control computer. The main control computer automatically adjusts the corresponding state system based on the real-time monitored pressure value and the data change trend of the pressure value to balance the current cavity pressure at the pressure control value. When the data exceeds the standard, the system automatically adjusts its own perfusion and suction state to quickly achieve a balanced perfusion and suction state while maintaining a certain cavity pressure. The perfusion parameters include the perfusion flow rate gear, and the suction parameters include the opening of the pressure relief valve and the suction pressure threshold.

[0084] The main control unit's pressure regulation modes include a coarse adjustment mode, a fine adjustment mode, and a mixed adjustment mode. The coarse adjustment mode is for extreme intracavity pressure, while the fine adjustment mode is for a small pressure difference between the intracavity pressure and the pressure control value. The mixed adjustment mode is for situations where the intracavity pressure is not extreme but has a large deviation. For example, when the pressure difference between the intracavity pressure and the pressure control value is extreme, such as exceeding ±20 mmHg, the coarse adjustment mode is activated; when the pressure difference exceeds ±3 mmHg and is within ±8 mmHg, the fine adjustment mode is activated; and when the pressure difference exceeds ±8 mmHg and is within ±20 mmHg, the mixed adjustment mode is activated.

[0085] The pressure control value can be a point value or an interval value. In some embodiments of the present invention, referring to Figures 14-16, the pressure control value is 10 mmHg. When the pressure difference between the intracavitary pressure and the pressure control value is within ±3 mmHg, the pressure regulation process is started.

[0086] Please refer to Figure 14. When it is detected that the intracavitary pressure value exceeds the highest warning line, that is, the pressure difference between the intracavitary pressure and the pressure control value is in an extreme situation, for example, greater than 20 mmHg, the main control machine controls to reduce the perfusion flow gear and controls the suction pressure threshold so that the suction flow>perfusion flow. When the pressure difference of the intracavitary pressure exceeds the lowest warning line, the perfusion process gear is adjusted to the maximum, the pressure relief valve is opened, and the suction pressure threshold is adjusted to the threshold value under the stable state to achieve a rapid balance effect and enable the equipment to get out of the current state as soon as possible.

[0087] This speeds up the system response and reduces the static error, but the overshoot of this adjustment method will increase and the stability will deteriorate. In this embodiment, the perfusion process gear is adjusted to the lowest gear or the highest gear to speed up the pressure callback. At the same time, in order to avoid excessive pressure adjustment, the suction pressure threshold is adjusted to the suction pressure threshold in the stable state. The suction pressure threshold in the stable state refers to the corresponding suction pressure threshold when the intracavity pressure recorded by the main control machine reaches the pressure control value range.

[0088] Please refer to Figure 15. When the pressure difference is detected to be greater than ±3mmHg and within ±8mmHg, it means that the pressure difference in the cavity is not large. In order to maintain the perfusion demand during operation and keep the perfusion flow constant, the suction pressure threshold is controlled to dynamically balance the perfusion and control the internal pressure to the "pressure control value". In this state, there is no need to adjust the perfusion or open the pressure relief valve. Because these two adjustment methods will cause large fluctuations in the data. It is also easy to disrupt the current dynamic balance. Therefore, at this stage, it is necessary to start the system's fine-tuning mode, keep the perfusion gear running, and keep the pressure relief valve closed, and adjust the pressure by fine-tuning the suction pressure threshold. In addition, during the perfusion and suction process, there are many pipelines in the cavity, the pressure fluctuations are large, and the frequency of pressure detection is fast. The setting of the suction pressure threshold also needs to be adjusted in real time according to the changing trend of the data. In one embodiment of the present invention, when the pressure differential exceeds -3 mmHg and is within -8 mmHg, the perfusion flow rate is maintained at the same level, the pressure relief valve is closed, and perfusion continues at its current level. The uploaded data trends are monitored. If the pressure is rising, the suction pressure threshold is increased; if it is falling, the suction pressure threshold is decreased by a greater amount than the increase during the rising phase. This results in an overall downward trend in the suction pressure threshold during the data adjustment process, achieving a pressurization effect through fine-tuning. When the pressure differential exceeds 3 mmHg and is within 8 mmHg, the perfusion continues at its current level, and the uploaded data trends are monitored. If the pressure is rising, the suction pressure threshold is increased; if it is falling, the suction pressure threshold is decreased by a lesser amount than the increase during the rising phase. This results in an overall upward trend in the suction pressure threshold during the data adjustment process, achieving a decompression effect. By determining the current state of the pressure detection value and the data trends, the suction pressure threshold is adjusted to either an upward or downward trend, minimizing damage to the body cavity caused by large pressure fluctuations.

[0089] In some embodiments of the present invention, when it is detected that the pressure difference exceeds ±8mmHg and is within ±20mmHg, the perfusion flow rate is fine-tuned, the pressure relief valve is fine-tuned and the suction pressure threshold is fine-tuned to act on the intracavitary pressure together to achieve the effect of pressurization or decompression. Specifically, when it is detected that the pressure difference exceeds 8mmHg and is within 20mmHg, the perfusion flow rate is lowered and the trend of changes in the uploaded data is observed. If it is in an upward stage, the suction pressure threshold is increased. If it is in a downward trend, the "suction pressure threshold" is reduced and the magnitude of the reduction is less than the magnitude of the increase in the suction pressure threshold in the upward stage. In this way, in the process of data adjustment, there is an overall trend of increasing the "suction pressure threshold" to achieve decompression. Effect: When it is detected that the pressure difference exceeds -8mmHg and is within -20mmHg, the perfusion flow maintains the current operation, the pressure relief valve is opened in stages, and the change trend of the uploaded data is observed. If it is in an upward stage, the suction pressure threshold is increased. If it is in a downward trend, the "suction pressure threshold" is reduced and the reduction amplitude is greater than the amplitude of increasing the suction pressure threshold in the upward stage; in this way, during the data adjustment process, there is an overall trend to reduce the "suction pressure threshold" to achieve a pressurization effect; in this embodiment, the adjustment amplitude of the suction pressure threshold increases with the increase of the pressure difference between the intracavitary pressure and the pressure control value. In this way, the combination of coarse adjustment and fine adjustment is achieved through the amplitude of the suction pressure threshold, so that the intracavitary pressure quickly reaches the pressure control value, avoiding tissue damage caused by excessive pressure fluctuations in the body.

[0090] For example, the relationship between the negative pressure suction flow rate (unit: ml / min) and the corresponding suction pressure threshold is statistically analyzed and divided into 12 categories. They are -5mmhg, -10mmhg, -15mmhg, -20mmhg, -25mmhg, -30mmhg, -35mmhg, -40mmhg, -45mmhg, -50mmhg, -60mmhg, and -70mmhg. This value is generally used as the system's default initial value when the system is turned on. Later, as dynamic equilibrium progresses, the balance point value will be updated to achieve a dynamic equilibrium effect.

[0091] The pressure difference Pa (unit: mmhg) between the cavity pressure and the pressure control value is counted and then classified. The cavity pressure has the following 13 states: 1: >20, 2: 15 <Pa<=20,3:10<Pa<=15,4:8<Pa<=10,5:5<Pa<=8, 6:3<Pa<=5,7:-3<Pa<=3,8:-5 <Pa<=-3 ,9:-8<Pa<=-5,10:-10<Pa<=-8,11:-15<Pa<=-10, 12:-20<Pa<=-15 13:-20<Pa。

[0092] According to the above statistical classification, compare the newly collected pressure data in the cavity with the historical data, and based on the change trend of the historical data, quickly achieve the dynamic balance of perfusion and aspiration by adjusting the perfusion, aspiration, and pressure relief valves.

[0093] According to the pressure difference Pa (unit: mmHg) between the pressure in the cavity and the pressure control value, the following processing methods are provided in this embodiment:

[0094] 1. (Pa > 20): The perfusion runs at the current gear - 4, increasing the aspiration pressure. According to the negative pressure aspiration flow corresponding to the statistically obtained aspiration pressure threshold, strengthen the aspiration flow so that the aspiration flow > perfusion flow; and observe the change trend of the uploaded data. If it continues to rise, adjust the perfusion to the lowest gear, and adjust the aspiration pressure threshold to the threshold at the balanced state until the current pressure in the cavity returns to the "pressure control value", and then restore the perfusion flow. If it continues to decline, adjust the perfusion flow according to the change requirements, and increase the aspiration pressure threshold to achieve the pressure reduction effect;

[0095] 2. (15 < Pa <= 20): The perfusion runs at the current gear - 3, observing the change trend of the uploaded data. If it is in the rising stage, increase the "aspiration pressure threshold + 5"; if it is in the declining trend, decrease the "aspiration pressure threshold - 2". In this way, during the data adjustment process, there is an overall tendency to increase the "aspiration pressure threshold"; achieving the pressure reduction effect;

[0096] 3. (10 < Pa <= 15): The perfusion runs at the current gear - 2, observing the change trend of the uploaded data. If it is in the rising stage, increase the "aspiration pressure threshold + 5"; if it is in the declining trend, decrease the "aspiration pressure threshold - 3". In this way, during the data adjustment process, there is an overall tendency to increase the "aspiration pressure threshold". Achieving the pressure reduction effect;

[0097] 4. (8 < Pa <= 10): The perfusion runs at the current gear - 1, observing the change trend of the uploaded data. If it is in the rising stage, increase the "aspiration pressure threshold + 4"; if it is in the declining trend, decrease the "aspiration pressure threshold - 1". In this way, during the data adjustment process, there is an overall tendency to increase the "aspiration pressure threshold". Achieving the pressure reduction effect;

[0098] 5. (5 < Pa <= 8): The perfusion maintains the current operation, observing the change trend of the uploaded data. If it is in the rising stage, increase the "aspiration pressure threshold + 3"; if it is in the declining trend, decrease the "aspiration pressure threshold - 1". In this way, during the data adjustment process, there is an overall tendency to increase the "aspiration pressure threshold". Achieving the pressure reduction effect;

[0099] 6. (3 < Pa <= 5): Observe the changing trend of the uploaded data. If it is in an upward stage, increase the "suction pressure threshold + 2"; if it is in a downward trend, decrease the "suction pressure threshold - 1". In this way, during the data adjustment process, there is an overall tendency to increase the "suction pressure threshold", achieving a decompression effect;

[0100] 7. (-3 < Pa <= 3): Maintain the current state, start timing, record the data. When a certain time is reached, record the current suction pressure threshold (i.e., the suction pressure threshold corresponding to the stable state), and update it in real time. When the state is disrupted, restart the timing. The saved value can be used during the dynamic adjustment process to quickly restore the equilibrium state;

[0101] 8. (-5 < Pa <= -3): The perfusion maintains the current operation. Observe the changing trend of the uploaded data. If it is in an upward stage, increase the "suction pressure threshold + 1"; if it is in a downward trend, decrease the "suction pressure threshold - 2". In this way, during the data adjustment process, there is an overall tendency to decrease the "suction pressure threshold", achieving a pressurization effect;

[0102] 9. (-8 < Pa <= -5): The perfusion maintains the current operation. Observe the changing trend of the uploaded data. If it is in an upward stage, increase the "suction pressure threshold + 1"; if it is in a downward trend, decrease the "suction pressure threshold - 3". In this way, during the data adjustment process, there is an overall tendency to decrease the "suction pressure threshold", achieving a pressurization effect;

[0103] 10. (-10 < Pa <= -8): The perfusion maintains the current operation. Periodically open the pressure relief valve. Observe the changing trend of the uploaded data. If it is in an upward stage, increase the "suction pressure threshold + 1"; if it is in a downward trend, decrease the "suction pressure threshold - 4". In this way, during the data adjustment process, there is an overall tendency to decrease the "suction pressure threshold", achieving a pressurization effect;

[0104] 11. (-15 < Pa <= -10): The perfusion maintains the current operation. Periodically open the pressure relief valve. Observe the changing trend of the uploaded data. If it is in an upward stage, increase the "suction pressure threshold + 3"; if it is in a downward trend, decrease the "suction pressure threshold - 5". There is an overall tendency to decrease the "suction pressure threshold", achieving a pressurization effect;

[0105] 12. (-20 < Pa <= -15): The perfusion runs at the current gear + 3, open the pressure relief valve, and adjust the "suction pressure threshold" to the threshold value in the stable state. Observe the changing trend of the uploaded data. If it is in an upward stage, increase the "suction pressure threshold + 2"; if it is in a downward trend, decrease the "suction pressure threshold - 5". In this way, during the data adjustment process, there is an overall tendency to decrease the "suction pressure threshold", achieving a pressurization effect;

[0106] 13. (Pa < -20) Run the device at the current gear +4, open the pressure relief valve, and adjust the suction pressure threshold to the threshold value under stable conditions to achieve a rapid balance effect and allow the device to exit the current state as soon as possible.

[0107] As described above, by analyzing historical data, data analysis is performed on the intracavitary pressure value, pressure control value and pressure threshold, so as to dynamically adjust the perfusion flow and suction flow to achieve a balance of intracavitary pressure.

[0108] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "specific embodiments," "optional embodiments," "examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0109] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A sheath tube with a pressure measuring function, the sheath tube comprising a sheath tube body, the sheath tube body having a main channel extending from a proximal end to a distal end and a pressure measuring channel, the proximal end of the pressure measuring channel being provided with an interface; characterized in that: The sheath tube further comprises a pressure detection device, and the pressure detection device comprises: A housing, wherein the housing has a pressure measuring cavity and a mounting cavity, the pressure measuring cavity has an air inlet for communicating with the sheath tube pressure measuring interface and a vent for communicating with the outside, and a switch is provided at the vent; A pressure detection assembly, which is arranged in the installation cavity and includes a gauge pressure sensor, a voltage adjustment circuit, an operational amplifier circuit and a conversion circuit. The gauge pressure sensor, the voltage adjustment circuit, the operational amplifier circuit and the conversion circuit are electrically connected. The gauge pressure sensor converts the pressure signal in the pressure measuring cavity into a voltage signal. The voltage adjustment circuit is used to increase the voltage difference of the voltage signal, and the operational amplifier circuit multiplies the increased voltage difference; the conversion circuit is used to convert the multiplied voltage signal into a pressure value; Aerogel insulation is encapsulated on the surface of the pressure detection component to transmit pressure.

2. The sheath tube according to claim 1, characterized in that: The gauge pressure sensor has an input voltage positive electrode (+vin), an input voltage negative electrode GND (-vin), an analog signal output voltage positive electrode (+out), and an analog signal output voltage negative electrode (-out); the voltage adjustment circuit at least includes a first resistor (R1) and a second resistor (R3), the first resistor (R1) is connected in parallel between the input voltage positive electrode (+vin) and the analog signal output voltage positive electrode (+out), and the second resistor (R3) is connected in parallel between GND (-vin) and the analog signal output voltage negative electrode (-out).

3. The sheath tube according to claim 1, characterized in that: The operational amplifier circuit is a GS8332 precision operational amplifier chip, which amplifies the voltage difference 100 times.

4. The sheath tube according to claim 1, characterized in that: The resistance values ​​of the first resistor (R1) and the second resistor (R3) are 100K.

5. The sheath tube according to claim 1, characterized in that: The conversion circuit is a single-chip microcomputer stm32f103c8t6.

6. The sheath tube according to claim 1, characterized in that: The housing comprises: A base, wherein a pressure measuring tube for forming a pressure measuring cavity is disposed on the base, an air inlet is disposed at one end of the pressure measuring tube, and a vent is formed at the other end, and an outlet is disposed on the pressure measuring tube for the gas in the pressure measuring tube to flow out; An upper cover, the upper cover is arranged above the base; A PCB board, the PCB board is located inside the base and fixed on the upper cover, the PCB board integrates a pressure detection component and a control circuit, the pressure detection component is arranged directly at the outlet and is sealed by an aerogel insulating member; A control button, which is disposed on the housing and is in communication connection with the control circuit; A connecting cable is connected to the conversion circuit to output a pressure test value.

7. The method for detecting a sheath tube according to any one of claims 1 to 6, characterized in that: The detection method comprises the following steps: Step 1) Conversion stage: The gauge pressure sensor converts the pressure signal into a μV voltage; Step 2) Increasing the voltage difference: By connecting the first resistor (R1) in parallel between the positive pole of the input voltage (+vin) and the positive pole of the analog signal output voltage (+out), and connecting the second resistor (R3) in parallel between the negative pole of the input voltage GND (-vin) and the negative pole of the analog signal output voltage (-out), the voltage difference is increased to reach the mV level to meet the minimum voltage difference requirement of the operational amplifier circuit; Step 3) Op amp stage: Through the op amp circuit, the voltage difference is amplified 100 times to reach the V (volt) level; range (0.5-3.0V) Step 4) Conversion stage: the voltage difference in step 3) is converted into a pressure value output through a conversion circuit; Step 5) Collection phase: The gauge pressure sensor collects data multiple times, and the microcontroller removes the extreme values ​​and calculates the average value to convert it into a pressure value output.

8. A pressure detection device, characterized in that: The pressure detection device adopts the pressure detection device according to any one of claims 1 to 6; the pressure detection device comprises: A housing, wherein the housing has a pressure measuring cavity and a mounting cavity, the pressure measuring cavity has an air inlet for communicating with the sheath tube pressure measuring interface and a vent for communicating with the outside, and a switch is provided at the vent; A pressure detection assembly, which is arranged in the installation cavity and includes a gauge pressure sensor, a voltage adjustment circuit, an operational amplifier circuit and a conversion circuit. The gauge pressure sensor, the voltage adjustment circuit, the operational amplifier circuit and the conversion circuit are electrically connected. The gauge pressure sensor converts the pressure signal in the pressure measuring cavity into a voltage signal. The voltage adjustment circuit is used to increase the voltage difference of the voltage signal, and the operational amplifier circuit multiplies the increased voltage difference; the conversion circuit is used to convert the multiplied voltage signal into a pressure value; an aerogel insulator which is encapsulated on the surface of the pressure detection component to transmit pressure; Preferably, the gauge pressure sensor has an input voltage positive electrode (+vin), an input voltage negative electrode GND (-vin), an analog signal output voltage positive electrode (+out), and an analog signal output voltage negative electrode (-out); the voltage adjustment circuit at least includes a first resistor (R1) and a second resistor (R3), the first resistor (R1) is connected in parallel between the input voltage positive electrode (+vin) and the analog signal output voltage positive electrode (+out), and the second resistor (R3) is connected in parallel between GND (-vin) and the analog signal output voltage negative electrode (-out); Further preferably, the housing comprises: A base, wherein a pressure measuring tube for forming a pressure measuring cavity is disposed on the base, an air inlet is disposed at one end of the pressure measuring tube, and a vent is formed at the other end, and an outlet is disposed on the pressure measuring tube for the gas in the pressure measuring tube to flow out; An upper cover, the upper cover is arranged above the base; A PCB board, the PCB board is located inside the base and fixed on the upper cover, the PCB board integrates a pressure detection component and a control circuit, the pressure detection component is arranged directly at the outlet and is sealed by an aerogel insulating member; A control button, which is disposed on the housing and is in communication connection with the control circuit; A connecting cable is connected to the conversion circuit to output a pressure test value.

9. An intelligent constant pressure controlled perfusion and suction system, characterized in that: The system includes The sheath tube according to claims 1 to 6, wherein the sheath tube body further comprises a suction channel; An endoscope, wherein the endoscope is inserted into the sheath tube and a liquid delivery channel is formed in the endoscope; a perfusion device, the perfusion device being in communication with the liquid delivery channel and being used for injecting perfusion liquid into the body cavity; A suction device, the suction device is connected to the suction channel to extract the liquid in the human body cavity, and the perfusion device cooperates with the suction device to maintain the cavity at a suitable pressure; A main control machine is connected to the conversion circuit, the injection device and the suction device for communication. The main control machine controls the flow rate and pressure of the injection device and the suction device according to the pressure value output by the conversion circuit.

10. The constant pressure control method of the perfusion suction system according to claim 9, characterized in that: The method comprises the following steps: Step 1) Preset the maximum warning pressure value, the minimum warning pressure value, the pressure control value, and the perfusion flow rate gear; Step 2) The main control machine controls the delivery of perfusion liquid into the perfusion device and the suction of the suction device, and the intracavitary pressure and negative pressure suction pressure are collected: Step 3) The pressure detection device collects the pressure in the cavity and transmits it to the main control machine. The main control machine dynamically adjusts the perfusion and suction states according to the real-time monitored pressure value and the data change trend of the pressure value, so that the current cavity pressure is balanced at the pressure control value, and the perfusion and suction balance state is achieved. The perfusion parameters include the perfusion flow rate gear, and the suction parameters include the opening of the pressure relief valve and the suction pressure threshold; The main control machine pressure regulation mode includes a coarse adjustment mode, a fine adjustment mode and a mixed adjustment mode. The coarse adjustment mode is for the case where the cavity pressure is in an extreme situation, the fine adjustment mode is for the case where the pressure difference of the cavity pressure from the pressure control value is small, and the mixed adjustment mode is for the case where the cavity pressure does not reach an extreme situation but the deviation value is large; When the pressure difference between the intracavitary pressure and the pressure control value exceeds ±20mmHg, the coarse adjustment mode is started; when the pressure difference exceeds ±3mmHg and is within ±8mmHg, the fine adjustment mode is started; when the pressure difference is detected to be more than ±8mmHg and within ±20mmHg, the mixed adjustment mode is started; the coarse adjustment mode includes the following steps: when the pressure value in the body cavity exceeds the highest warning line, the main control machine controls to reduce the perfusion flow gear, controls the suction pressure threshold so that the suction flow>perfusion flow, and when the pressure difference in the cavity pressure exceeds the lowest warning line, the perfusion process gear is increased, the pressure relief valve is opened, and the suction pressure threshold is adjusted to the threshold value under the stable state, so as to achieve a rapid balance effect and make the pressure in the cavity get out of the extreme state as soon as possible; The fine adjustment mode includes the following steps: maintaining the filling gear to maintain operation, and keeping the pressure relief valve closed, and adjusting the pressure by fine adjustment of the suction pressure threshold; When the pressure difference exceeds -3mmHg and is within -8mmHg, keep the perfusion flow rate gear unchanged, keep the pressure relief valve closed, maintain the current perfusion operation, observe the change trend of the uploaded data, if it is in the rising stage, increase the suction pressure threshold, if it is in a downward trend, reduce the suction pressure threshold and the reduction amplitude is greater than the amplitude of increasing the suction pressure threshold in the rising stage. In this way, during the data adjustment process, there is an overall trend to reduce the suction pressure threshold, and achieve the pressurization effect in a fine-tuning manner; when the pressure difference exceeds 3mmHg and is within 8mmHg, maintain the current gear operation of the perfusion, observe the change trend of the uploaded data, if it is in the rising stage, increase the suction pressure threshold, if it is in a downward trend, reduce the suction pressure threshold and the reduction amplitude is less than the amplitude of increasing the suction pressure threshold in the rising stage. During the data adjustment process, there is an overall trend to increase the suction pressure threshold, and achieve the decompression effect; The mixed adjustment mode includes the following steps: by combining the adjustment of the perfusion flow gear, the pressure relief valve and the suction pressure threshold, the fine adjustment of the perfusion flow, the fine adjustment of the pressure relief valve and the fine adjustment of the suction pressure threshold are combined to act on the intracavitary pressure together to achieve the effect of pressurization or decompression; when the pressure difference is detected to exceed 8mmHg and is within 20mmHg, the perfusion flow is appropriately reduced, and the change trend of the uploaded data is observed. If it is in the rising stage, the suction pressure threshold is increased. If it is in a downward trend, the suction pressure threshold is reduced and the reduction amplitude is less than the amplitude of the increase of the suction pressure threshold in the rising stage; in this way, in the process of data adjustment, there is an overall trend of increasing the suction pressure threshold to achieve the decompression effect; when the pressure difference is detected to be lower than -8mmHg and within -20mmHg, the perfusion flow maintains the current operation, the pressure relief valve is opened in stages, and the change trend of the uploaded data is observed. If it is in the rising stage, the suction pressure threshold is increased, if it is in a downward trend, the suction pressure threshold is reduced and the reduction amplitude is greater than the amplitude of the increase of the suction pressure threshold in the rising stage; in this way, in the process of data adjustment, there is an overall trend of reducing the suction pressure threshold to achieve the pressurization effect.

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