A cryoablation system for convenient fluid flow state monitoring

Abstract

The present application relates to a cryoablation system that facilitates fluid flow state monitoring, which is composed of a cryoablation device and a cryoablation catheter. The cryoablation device includes a human-machine interaction module, a control module, and an air circuit module. The human-machine interaction module is electrically connected to the control module, the control module is electrically connected to the air circuit module, and the air circuit module is connected to the cryoablation catheter. The cryoablation catheter includes a catheter elongated shaft, a catheter handle arranged at the proximal end of the catheter elongated shaft, a freezing unit arranged at the distal end of the catheter elongated shaft, an air inlet pipe and an air return pipe arranged in the cavity of the catheter elongated shaft, the air inlet pipe and the air return pipe are in fluid communication with the inner cavity of the freezing unit, and a gas flow state monitoring sensor is arranged at the proximal end of the air return pipe. The system effectively detects and prevents catheter safety risks by setting multiple safety devices, greatly reducing its risks during application.

Description

Technical Field

[0001] The present application belongs to the field of minimally invasive interventional treatment, and specifically relates to a cryoablation system that facilitates fluid flow status monitoring. Background Art

[0002] Cryoablation is a new technology for treating arrhythmias. Its principle is to absorb heat and evaporate liquid refrigerant to take away tissue heat, reduce the temperature of the target ablation site, and destroy abnormal cell tissue, thereby achieving the purpose of treatment. The catheter used in cryoablation needs to enter the human body and go deep into the lesion site. Any cryoablation system has certain safety risks, and how to effectively detect and prevent related risks is the main problem that needs to be solved in this field. For the cryoablation process, there are two main safety risks: first, congestion in the catheter gas circuit causes the balloon to operate at a higher pressure, posing a safety hazard; second, damage to the catheter causes human blood to enter the catheter, causing partial blood loss in the patient. Although the probability of the above risks is extremely low, once the risk occurs, it will have an adverse effect on the patient's health and even life safety. Therefore, it is necessary to use safe and effective detection devices to accurately and effectively predict risks and prevent them in time.

[0003] For the first safety risk, the existing detection system generally determines whether the catheter gas circuit is blocked by detecting the intake pressure or flow rate. However, this method has the defect of delayed detection response. If the gas circuit is blocked, the balloon of the freezing unit will be over-pressurized within two seconds. The gas circuit is generally blocked for 2-3 seconds or even longer before it can be effectively detected and the gas source can be shut down, which poses an obvious safety hazard. Therefore, it is urgent to provide a more responsive gas circuit blockage detection method to achieve instantaneous and accurate detection of gas circuit blockage and real-time feedback to avoid the risk of balloon over-pressure.

[0004] For the second safety risk, the existing solution is mainly to detect leaked liquid (generally patient blood) by setting a photoelectric sensor in the catheter. The photoelectric sensor is to install the transmitter and receiver face to face on both sides of a transparent catheter. When there is no obstruction, the light source of the transmitter shines on the receiver through the transparent catheter. After the receiver receives the light, it is determined that there is no foreign matter. When liquid is accidentally immersed, the light source of the transmitter is partially or completely blocked, and the receiver receives part of the light or cannot receive the light, that is, it is determined that there is a foreign matter, that is, there is an unexpected liquid invasion. It is inevitable that liquid (generally patient blood) will enter the catheter when detecting liquid leakage by this method, thereby affecting the health of the patient. In addition, since the photoelectric sensor needs to set the transmitter and receiver in the catheter, it will inevitably increase the outer diameter of the catheter, and then there is a problem that it cannot adapt to some blood vessels. Third, the sensor requires a power supply line and a signal line, and at least four wires need to be set in the catheter. Adding four wires in the narrow space of the catheter is very likely to affect its performance. Therefore, it is urgent to provide a safety device that can detect liquid leakage into the catheter. The device has a simple structure and does not increase the size of the catheter. At the same time, it is necessary to avoid the risk of blood loss caused by liquid entering the catheter. Summary of the invention

[0005] The purpose of this application is to overcome the existing technical defects and design a cryoablation system that is convenient for monitoring fluid flow status. The cryoablation system effectively detects and prevents catheter safety risks by setting up multiple safety devices, thereby greatly reducing the risks during the application of the cryoablation system.

[0006] The purpose of this application is achieved through the following technical solutions:

[0007] A cryoablation system for monitoring fluid flow status, comprising a cryoablation device and a cryoablation catheter, the cryoablation device comprising a human-machine interaction module, a control module, and an air circuit module, the human-machine interaction module being electrically connected to the control module, the control module being electrically connected to the air circuit module, the air circuit module being connected to the cryoablation catheter, the cryoablation catheter comprising a slender catheter shaft, a catheter handle arranged at the proximal end of the slender catheter shaft, a freezing unit arranged at the distal end of the slender catheter shaft, an air inlet pipe and an air return pipe arranged in the cavity of the slender catheter shaft, the air inlet pipe and the air return pipe being connected to the inner cavity fluid of the freezing unit, and a gas flow status monitoring sensor being arranged at the proximal end of the air return pipe.

[0008] The purpose of this application can also be achieved through the following technical solutions:

[0009] In one embodiment, a negative pressure suction pump is provided at the proximal end of the air return pipe, and the gas flow state monitoring sensor is provided at the inlet of the negative pressure suction pump.

[0010] In a preferred embodiment, the gas flow state monitoring sensor is a pressure sensor, a flow sensor or a flow velocity sensor.

[0011] In one embodiment, a liquid blocking mechanism is disposed in the distal end of the elongated shaft of the catheter, and the liquid blocking mechanism has a hydrophobic microporous structure.

[0012] In a preferred embodiment, the surface properties and dimensional structure of the liquid sealing mechanism conform to the following quantitative relationship:

[0013]

[0014] in P is the absolute pressure of the liquid at the leakage point, λ is the surface tension coefficient, r is the equivalent hydraulic radius of the pore, and Ѳ is the contact angle of the liquid on the pore wall. In the calculation, for circular pores, r is the pore radius. For non-circular or other irregular pore structures such as square, triangle, etc., r is the equivalent hydraulic radius of the pore structure.

[0015] In a preferred embodiment, the liquid blocking mechanism is a hydrophobic coating coated on the inner wall (inner surface) of the slender shaft of the catheter and the outer walls (outer surfaces) of the air inlet pipe and the air return pipe.

[0016] In a preferred embodiment, the liquid blocking mechanism is disposed in a space defined by the inner wall of the slender shaft of the catheter and the outer walls of the air inlet pipe and the air return pipe, and the liquid blocking mechanism is an array having a hydrophobic microporous structure.

[0017] In a preferred embodiment, the liquid blocking mechanism is a hydrophobic thread placed in the gap between the inner wall of the slender shaft of the catheter and the outer walls of the air inlet pipe and the air return pipe.

[0018] In a preferred embodiment, the liquid blocking mechanism is a combination of a hydrophobic coating, a hydrophobic thread, and a hydrophobic microporous structure, wherein the combination includes any two structures used in combination or three structures combined together.

[0019] In a preferred embodiment, the liquid blocking mechanism has a millimeter-scale, micrometer-scale or nanometer-scale pore structure.

[0020] In a preferred embodiment, the liquid blocking mechanism is a honeycomb array, or the hydrophobic microporous structure of the liquid blocking mechanism is an ordered array or a disordered array, and the liquid blocking mechanism can prevent liquid from passing through but allow gas to pass through.

[0021] In one embodiment, a water vapor sensor is disposed in the cryoablation system, the water vapor sensor is in fluid communication with the elongated shaft of the catheter, and the water vapor sensor is electrically connected to the control module.

[0022] In a preferred embodiment, the cryoablation device is connected to the catheter handle via a flexible connecting tube, and the water vapor sensor is disposed inside the catheter handle, inside the flexible connecting tube, or inside the cryoablation device.

[0023] In one embodiment, the water vapor sensor is a humidity sensor.

[0024] In a preferred embodiment, a negative pressure pump is provided inside the cryoablation device, the negative pressure pump is fluidically connected to the elongated shaft of the catheter, the negative pressure pump is electrically connected to a control module, and the water vapor sensor is provided on the inlet side of the negative pressure pump.

[0025] In a preferred embodiment, a water molecule isolator is provided between the water vapor sensor and the negative pressure pump.

[0026] In a preferred embodiment, a stop valve is provided between the water vapor sensor and the negative pressure pump, and the stop valve is electrically connected to the control module.

[0027] In one embodiment, the freezing unit includes a freezing bladder and a protective bladder, wherein the protective bladder is wrapped outside the freezing bladder, and the air inlet pipe and the air return pipe are in fluid communication with the inner cavity of the freezing bladder.

[0028] In a preferred embodiment, a thermocouple is also arranged in the slender shaft of the catheter, and the thermocouple is connected to the control module wire. The thermocouple includes a positive wire and a negative wire. The distal end of the positive wire and the distal end of the negative wire are both arranged in the protective capsule, and the distal end of the positive wire is connected to the distal end of the negative wire. A safety device is arranged on the thermocouple.

[0029] In a preferred embodiment, the safety device consists of a positive electrode accessory wire and a negative electrode accessory wire, the proximal end of the positive electrode accessory wire is electrically connected to the positive electrode wire, the distal end of the positive electrode accessory wire is arranged in the protective capsule, the proximal end of the negative electrode accessory wire is electrically connected to the negative electrode wire, the distal end of the negative electrode accessory wire is arranged in the protective capsule, and the distal end of the positive electrode accessory wire is spaced a distance from the distal end of the negative electrode accessory wire, that is, the distal end of the positive electrode accessory wire is not in direct contact with the distal end of the negative electrode accessory wire.

[0030] In a preferred embodiment, a catheter connecting end is provided on the cryoablation device, one end of the catheter connecting end is fixedly connected to the air circuit module, and the other end of the catheter connecting end is connected to the catheter handle via a flexible connecting tube, and the air inlet pipe, the air return pipe, the positive electrode wire, the negative electrode wire, the positive electrode auxiliary wire and the negative electrode auxiliary wire pass through the lumen of the flexible connecting tube and the catheter connecting end to be connected to the cryoablation device.

[0031] In a preferred embodiment, the conduit connection end is threadedly connected to the gas circuit module.

[0032] In a preferred embodiment, the proximal end of the air inlet pipe is connected to the air circuit module, and the distal end of the air inlet pipe is arranged in the distal end of the freezing capsule, and the proximal end of the return air pipe is connected to the air circuit module, and the distal end of the return air pipe is arranged in the proximal end of the freezing capsule.

[0033] In a preferred embodiment, the proximal end of the air inlet pipe and the proximal end of the air return pipe are both snap-connected to the air circuit module.

[0034] In a preferred embodiment, the safety device is an opening respectively arranged on the distal parts of the positive wire and the negative wire, and the opening is arranged on the distal side of the liquid sealing mechanism. The opening exposes the conductive metal wires in the positive wire and the negative wire, and the exposed conductive metal wires of the positive wire and the negative wire are not in direct contact.

[0035] In a preferred embodiment, a catheter connecting end is provided on the cryoablation device, one end of the catheter connecting end is fixedly connected to the air circuit module, and the other end of the catheter connecting end is connected to the catheter handle via a flexible connecting tube, and the air inlet pipe, the air return pipe, the positive electrode wire and the negative electrode wire pass through the lumen of the flexible connecting tube and the catheter connecting end to be connected to the cryoablation device.

[0036] Compared with the prior art, the advantages of this application are:

[0037] 1. The present application is provided with a gas flow status monitoring sensor at the proximal end of the return air pipe. Existing catheter gas circuit blockage detection is generally performed by detecting the intake air or the internal pressure of the balloon, which has the risk of delayed response and thus causing the instantaneous pressure in the balloon to be too high. The present application can realize the immediate monitoring of the gas circuit blockage without delay by providing a gas flow status monitoring sensor at the proximal end of the return air pipe, which can prevent the internal pressure of the refrigeration unit balloon from exceeding the rated requirement value, and the safety is significantly better than the existing products.

[0038] 2. The present application designs a liquid blocking mechanism at the distal end of the slender shaft of the catheter, which can automatically intercept the leaked liquid from entering the catheter by using the liquid's own surface tension. Existing catheter liquid leakage detection devices all detect liquid after a large amount of liquid enters the catheter through photoelectric sensors or other liquid sensors, and cannot effectively detect liquid before it enters the catheter, and therefore cannot solve the technical problem of liquid entering the catheter after leakage. The present application is based on the physical property that the surface tension of liquid passing through pores with different surface characteristics has different directions. By setting a hydrophobic pore structure, the reverse surface tension of the liquid itself is used to automatically limit the flow of the liquid itself, successfully locking the liquid, preventing the leaked liquid from entering the catheter, and thus preventing patients from losing blood due to catheter liquid leakage.

[0039] 3. The present application sets a water vapor sensor in the cryoablation system, which can effectively intercept liquid from entering the catheter and effectively detect liquid leakage, solving the problem of being unable to effectively detect liquid leakage while preventing leaked liquid from entering the catheter. The liquid blocking mechanism set in the catheter of the present application can allow water vapor gas molecules to pass through while intercepting liquid from entering the catheter. Therefore, a water vapor sensor can be set in the extracorporeal area of ​​the catheter or at the end of the device, thereby realizing liquid leakage detection by detecting the content of water vapor molecules. Since the liquid blocking mechanism only needs to be coated or filled in the slender shaft of the catheter, this method does not increase the size of the catheter entering the human body.

[0040] 4. The photoelectric sensors used in the liquid leakage detection systems of some existing catheters require power supply lines and signal lines, and at least four wires are required. Adding four wires to the narrow space of the catheter lumen is likely to increase the size of the catheter lumen, thereby increasing the size of the wound and affecting the performance of the catheter. This application does not require the installation of sensor-type components, so there is no need to add a power supply line to the catheter, avoiding electric shock injuries to the patient in extreme cases. In addition, the method of relatively internally setting sensors can further reduce the size of the catheter, improve the safety of the interventional catheter, increase the flexibility of the catheter, can adapt to different vascular conditions, and expand the scope of use.

[0041] 5. The present application improves the thermocouples that are usually set in the catheter, utilizes the conductivity of metal, and realizes the detection of liquid through two wires, avoiding the placement of photoelectric sensors or liquid sensors, streamlining the structure, and saving the internal space of the catheter lumen. Compared with the method of setting a sensor inside the catheter lumen, the size of the catheter is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a schematic diagram of the overall structure of a cryoablation system for convenient fluid flow status monitoring according to the present application.

[0043] Figure 2This is a schematic structural diagram of a catheter gas circuit blockage detection device for a cryoablation device according to an embodiment of the present application.

[0044] Figure 3a to Figure 3c A schematic diagram of determining the blockage of a conduit gas circuit in an embodiment of the present application.

[0045] Figure 4 This is a schematic structural diagram of the distal end of a cryoablation catheter according to an embodiment of the present application.

[0046] Figure 5 This is a structural schematic diagram of a first implementation manner of a liquid sealing mechanism of an embodiment of the present application.

[0047] Figure 6 This is a structural schematic diagram of a second implementation of a liquid sealing mechanism of an embodiment of the present application.

[0048] Figure 7 This is a structural schematic diagram of a third implementation manner of a liquid sealing mechanism of an embodiment of the present application.

[0049] Figure 8 Schematic diagram of liquid force analysis in a single pore of a liquid sealing mechanism according to an embodiment of the present application.

[0050] Fig. 9 A schematic diagram of an implementation of providing a water vapor sensor in the cryoablation system of the present application.

[0051] Fig.10 A schematic diagram of another embodiment of providing a water vapor sensor in the cryoablation system of the application.

[0052] Fig.11 This is a schematic structural diagram of a catheter connection end according to an embodiment of the present application.

[0053] Fig.12 This is a schematic structural diagram of the distal end of a cryoablation catheter according to another embodiment of the present application.

[0054] Fig.13 This is a schematic structural diagram of a catheter connection end according to another embodiment of the present application.

[0055] Fig.14 This is a schematic structural diagram of the distal end of a cryoablation catheter according to an embodiment of the present application. DETAILED DESCRIPTION

[0056] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and examples.

[0057] Embodiment 1

[0058] like Figure 1 and Figure 2 As shown, a cryoablation system for monitoring fluid flow status is composed of a cryoablation device 1 and a cryoablation catheter 2, wherein the cryoablation device includes a human-computer interaction module 11, a control module 12, and an air circuit module 13, wherein the human-computer interaction module 11 is electrically connected to the control module 12, and the control module 12 is electrically connected to the air circuit module 13, and the cryoablation catheter 2 includes a catheter slender shaft 23, a catheter handle 22 arranged at the proximal end of the catheter slender shaft 23, a freezing unit 24 arranged at the distal end of the catheter slender shaft 23, an air inlet pipe 25 and an air return pipe 26 arranged in the catheter slender shaft 23, wherein the air inlet pipe 25 and the air return pipe 26 are connected to the inner cavity fluid of the freezing unit 24, and a gas flow status monitoring sensor 15 is arranged at the proximal end of the air return pipe.

[0059] In one embodiment, if Figure 2 As shown, a negative pressure suction pump 14 is provided at the proximal end of the return air pipe, and the gas flow state monitoring sensor 15 is provided at the inlet of the negative pressure suction pump 14. The gas flow state monitoring sensor 15 is a pressure sensor, a flow sensor or a flow velocity sensor. When the pressure sensor detects that the gas pressure, flow or flow velocity suddenly drops by a certain ratio (the recommended value is 30% / s), it can be judged that the catheter gas circuit is blocked, and the control module 12 immediately closes the catheter inlet valve 16 to avoid excessive pressure inside the balloon. The setting of this structure can greatly reduce the risk of surgery.

[0060] like Figure 3a to Figure 3cAs shown, fluid transmission is a point-to-point sequential transmission process. The previous flow point can be regarded as the flow source of the next flow point, and the flow state of the flow source determines the flow state of all subsequent fluids. When the fluid circuit is blocked, the flow source of the entire fluid circuit does not instantly become 0, but the fluid flow rate at the blockage point first becomes 0. Therefore, the flow rate of the entire fluid circuit will not immediately become 0. Under the action of fluid inertia, the fluid flow rate of the fluid circuit before the blockage point will slowly decrease until zero, and the fluid in the fluid circuit after the blockage point will instantly become 0 because the flow rate of the flow source (i.e., the blockage point) instantly becomes 0. The fluid flow rate in the circuit after the blockage point instantly becomes completely 0. Therefore, setting the fluid flow state monitoring point at the proximal end of the return air pipe (such as monitoring point 1) can monitor the blockage state of the fluid circuit more quickly, close the air intake valve 16 in time, and avoid excessive pressure inside the balloon. The prior art generally uses a pressure sensor to detect the internal pressure of the balloon to determine whether the balloon is over-pressured or uses a flow sensor set in the air intake line to determine the blockage of the fluid circuit. If the blockage point is located at the end of the fluid circuit and the monitoring point is before the blockage point (such as monitoring point 2), there will be an obvious monitoring lag phenomenon. During the period from the blockage (time point A) to the delayed monitoring (time point B), due to the inertia of fluid transmission, the fluid continues to flow and gather inside the balloon, and the flow resistance is increased to infinity due to the blockage at the end of the fluid circuit. The fluid flow from the balloon to the outside drops rapidly to near zero. Therefore, the pressure inside the balloon will increase significantly within 1-2 seconds after the blockage of the fluid circuit occurs (the rate of increase is related to the air source pressure). Even if the internal pressure of the balloon is directly detected, as long as the blockage point is located in the fluid circuit behind the balloon, a monitoring lag will occur. The present application sets the monitoring point at the proximal end of the return air pipe. If a blockage occurs at any position of the entire catheter fluid circuit, the flow state information such as the flow rate, flow rate or pressure of the monitoring point will be fed back without delay (time point C). The signal is fed back to the control module 12 to immediately close the catheter air inlet valve 16, which can avoid the increase of the internal pressure of the balloon, thereby greatly reducing the risk of surgery.

[0061] Embodiment 2

[0062] This embodiment is different from the first embodiment in that Figure 1 and 4 As shown, a liquid blocking mechanism 28 is provided in the distal end of the catheter elongated shaft 23 and a water vapor sensor 29 is provided in the cryoablation system. The blocking structure 28 has a hydrophobic microporous structure (such as Figure 5As shown in the figure, the liquid blocking mechanism 28 is arranged in the space defined by the inner wall of the slender shaft 23 of the catheter and the outer walls of the air inlet pipe 25 and the air return pipe 26, and the liquid blocking mechanism 28 is an array 281 with a hydrophobic microporous structure. In one embodiment, the liquid blocking mechanism 28 has a pore structure of millimeter level, micrometer level or nanometer level. In a preferred embodiment, the liquid blocking mechanism 28 is a honeycomb array, or the hydrophobic microporous structure of the liquid blocking mechanism 28 is an array arranged in an orderly manner or an array arranged in a disordered manner, and the liquid blocking mechanism 28 can prevent liquid from passing through and allow gas to pass through. The present application designs a liquid blocking mechanism 28 in the distal end of the slender shaft of the catheter, which can automatically intercept the leaked liquid from entering the catheter by using the surface tension of the liquid itself. Existing catheter liquid leakage detection devices all detect through photoelectric sensors or other liquid sensors after a large amount of liquid enters the catheter, and cannot perform effective detection before the liquid enters the catheter, and thus cannot solve the technical problem of liquid entering the catheter after leakage. The present application is based on the physical property that the surface tension of liquid passing through pores with different surface characteristics has different directions. By setting a hydrophobic pore structure, the liquid's own reverse surface tension is used to automatically limit the liquid's own flow, successfully locking the liquid naturally and preventing the leaked liquid from entering the catheter, thereby preventing the patient from bleeding due to catheter liquid leakage.

[0063] In order to effectively inhibit blood from passing through the liquid blocking mechanism 28, the surface properties and size structure of the liquid blocking mechanism 28 conform to the following quantitative relationship:

[0064] (1)

[0065] In the above formula P is the absolute pressure of the liquid at the leakage point, λ is the surface tension coefficient, r is the pore radius, and Ѳ is the contact angle of the liquid on the pore wall.

[0066] The theoretical derivation process is as follows (see Figure 8 ):

[0067] Liquid surface tension (2)

[0068] The component of surface tension in the y direction is:

[0069] (3)

[0070] Assume that the absolute pressure of the liquid at the leakage point is P , then the axial force generated by the liquid pressure at the pore entrance can be expressed as:

[0071] (4)

[0072] When the axial force generated by the liquid pressure at the leakage point at the pore entrance is smaller than the surface tension component in the y direction, that is, When the surface tension is too great, the liquid cannot overcome the surface tension and pass through the pore, so the liquid can be effectively intercepted.

[0073] Substituting equation 3-4 into the equation, we can get:

[0074] (5)

[0075] The above formula can also be expressed as (1)

[0076] Therefore, as long as the inner diameter of the hydrophobic pore liquid blocking mechanism 28 is r The surface tension coefficient λ and the contact angle Ѳ with the blocked liquid conform to the above formula, and the liquid will be effectively blocked.

[0077] The above formula also holds true for non-circular or other irregular pore structures such as squares and triangles. r is the equivalent hydraulic radius of the pore structure.

[0078] In one embodiment, if Figure 4 As shown, the freezing unit 24 includes a freezing capsule 241 and a protective capsule 242, wherein the protective capsule 242 is wrapped outside the freezing capsule 241, and the air inlet pipe 25 and the air return pipe 26 are in fluid communication with the inner cavity of the freezing capsule 241. During the operation of the cryoablation system, if the protective capsule 242 is damaged, blood in the human body will enter the elongated shaft 23 of the catheter through the rupture, and the blood entering the elongated shaft 23 of the catheter will generate obvious surface tension opposite to the flow direction at the entrance of the liquid blocking mechanism 28, thereby inhibiting its flow.

[0079] In one embodiment, if Figure 6 As shown, the liquid blocking mechanism 28 is a hydrophobic coating 282 coated on the inner wall (inner surface) of the catheter slender shaft 23 and the outer surfaces of the air inlet pipe 25 and the air return pipe 26, which can achieve liquid interception and blocking effects.

[0080] In one embodiment, if Figure 7 The liquid blocking mechanism 28 is a hydrophobic thread 283 that is filled in the gap between the inner wall of the slender shaft 23 of the catheter and the outer walls of the air inlet pipe 25 and the air return pipe 26. The hydrophobic thread 283 can be of millimeter level, micrometer level, or nanometer level. The diameter of the hydrophobic thread 283 can be consistent or inconsistent. The hydrophobic pore structure formed between the hydrophobic threads 283 can form reverse surface tension for the liquid passing through it, thereby achieving liquid blocking. The higher the filling density of the hydrophobic thread 283, the smaller the thread diameter, and the corresponding equivalent hydraulic radius rThe smaller it is, the better the liquid plugging effect is, according to Formula 1. It is more convenient to achieve it by plugging with hydrophobic silk thread, and the processing cost is lower.

[0081] In a preferred embodiment, the hydrophobic coating 282, the hydrophobic thread 283, and the hydrophobic microporous structure 281 are used in pairs or in combination to improve the liquid blocking effect.

[0082] In one embodiment, if Figure 1 As shown, a water vapor sensor 29 is provided in the cryoablation system, and the water vapor sensor 29 is in fluid communication with the catheter slender shaft 23, and the water vapor sensor 29 is electrically connected to the control module 12. In a preferred embodiment, the cryoablation device 1 is connected to the catheter handle 22 via a flexible connecting tube 21, and the water vapor sensor 29 is provided inside the catheter handle 22, inside the flexible connecting tube 21, or inside the cryoablation device 1. When the catheter is damaged and fluid leakage occurs, external blood enters the catheter. Although the liquid cannot flow into the catheter due to the surface tension opposite to the flow direction, the water vapor partial pressure in the catheter is much lower than the saturated water vapor partial pressure, and the liquid evaporates and diffuses rapidly. Therefore, a small amount of vapor can smoothly pass through the liquid sealing mechanism 28 into the catheter, and is effectively detected by the water vapor sensor 29 provided inside the catheter handle 22. When the water vapor sensor 29 detects the liquid vapor, it transmits an electrical signal to the control module 12, and the control module 12 immediately gives feedback and issues a corresponding instruction to stop the operation. As shown in FIG. Fig. 9 As shown, the control module 12 closes the catheter air inlet valve 16 and turns on the negative pressure suction pump 14. The negative pressure suction pump 14 is arranged at the proximal end of the return air pipe 26 of the catheter to remove the gas in the catheter fluid circulation loop and reduce the risk of gas entering the blood through the damaged part of the catheter. The present application is provided with a water vapor sensor in the cryoablation system, which can effectively intercept the liquid from entering the catheter and effectively detect the liquid leakage, solving the problem of not being able to effectively detect the liquid leakage while preventing the leaked liquid from entering the catheter. The liquid blocking mechanism provided in the catheter of the present application can allow water vapor gas molecules to pass through while intercepting the liquid from entering the catheter. Therefore, a water vapor sensor can be provided in the extracorporeal area of ​​the catheter or at the device end, thereby realizing liquid leakage detection by detecting the content of water vapor molecules. Since the liquid blocking mechanism only needs to be coated or filled in the slender shaft of the catheter, this method does not increase the size of the catheter entering the human body.

[0083] In one embodiment, the water vapor sensor 29 is a humidity sensor, which monitors the water vapor level inside the conduit by monitoring the humidity change. Fig. 9As shown, a negative pressure pump 17 is arranged inside the cryoablation device 1, and the negative pressure pump 17 is in fluid communication with the slender shaft 23 of the catheter, and is used to keep the internal pressure of the slender shaft 23 of the catheter lower than the external blood pressure. The negative pressure pump 17 is electrically connected to the control module 12, and the water vapor sensor 29 is arranged on the inlet end side of the negative pressure pump 17. The negative pressure pump 17 can keep the inside of the catheter in a negative pressure environment to prevent the internal pressure of the catheter from being higher than the external blood pressure. When the catheter leaks, the internal pressure of the catheter is lower than the external blood pressure, which can prevent gas from entering the blood and causing the risk of gas embolism. When the system detects a catheter leak, the control module 12 turns off the negative pressure pump 17 to prevent the negative pressure pump 17 from continuously inhaling air and causing blood loss.

[0084] In one embodiment, if Fig.10 As shown, a stop valve 19 is provided between the water vapor sensor 29 and the negative pressure pump 17, and the stop valve 19 is electrically connected to the control module 12. Generally, after the negative pressure pump 17 is turned off, its rotor will still rotate for a certain period of time due to inertia. In order to avoid blood loss caused by its inertial negative pressure, the system sets a stop valve 19 in front of the negative pressure pump 17. When the system detects a catheter fluid leak, the stop valve 19 is closed in time, which can inhibit the continuous entry of gas into the system and reduce blood loss. In one embodiment, a water molecule isolator 18 is provided between the water vapor sensor 29 and the negative pressure pump 17. The water molecule isolator 18 can prevent water vapor molecules from passing through, but allow other gases to pass through, thereby increasing the water vapor content at the front end of the water molecule isolator 18 (i.e., the installation area of ​​the water vapor sensor 29) and improving the detection reaction speed.

[0085] Embodiment 3

[0086] The present embodiment is different from the second embodiment in that a guide wire lumen 27, a thermocouple 3 and a safety device 4 are arranged in the cryoablation catheter 2. Figure 1 and Figure 4As shown, a cryoablation system with multiple safety detection and prevention devices is composed of a cryoablation device 1 and a cryoablation catheter 2. The cryoablation device includes a human-machine interaction module 11, a control module 12, and an air circuit module 13. The human-machine interaction module 11 is electrically connected to the control module 12, and the control module 12 is electrically connected to the air circuit module 13. The cryoablation catheter 2 includes a catheter slender shaft 23, a catheter handle 22 arranged at the proximal end of the catheter slender shaft 23, a freezing unit 24 arranged at the distal end of the catheter slender shaft 23, an air inlet pipe 25, an air return pipe 26 and a guidewire lumen 27 arranged in the catheter slender shaft 23, and the freezing unit 24 includes a guide wire lumen 27. It includes a freezing capsule 241 and a protective capsule 242, wherein the protective capsule 242 is wrapped outside the freezing capsule 241, and the air inlet pipe 25 and the air return pipe 26 are in fluid communication with the inner cavity of the freezing capsule 241. A liquid blocking mechanism 28 is provided in the distal end of the catheter slender shaft 23, and the liquid blocking mechanism 28 is arranged in a space defined by the inner surface of the distal end of the catheter slender shaft 23 and the outer surfaces of the air inlet pipe 25, the air return pipe 26 and the guidewire lumen 27, or the liquid blocking mechanism 28 is a hydrophobic coating 282 coated on the inner wall (inner surface) of the catheter slender shaft 23 and the outer surfaces of the air inlet pipe 25, the air return pipe 26 and the guidewire lumen 27, which can achieve a liquid interception and blocking effect. Fig.11 and Fig.12 As shown, a thermocouple 3 is also arranged in the slender shaft 23 of the catheter, and the thermocouple 3 is connected to the control module 12 by wire. The thermocouple 3 includes a positive wire 31 and a negative wire 32. The distal end 311 of the positive wire 31 and the distal end 321 of the negative wire 32 are both arranged in the protective capsule 242, the distal end 311 of the positive wire 31 is connected to the distal end 321 of the negative wire 32, the proximal end of the positive wire 31 and the proximal end of the negative wire 32 are both electrically connected to the control module 12, and a safety device 4 is connected to the thermocouple 3. The safety device 4 is composed of a positive auxiliary wire 41 and a negative auxiliary wire 42. The proximal end of the positive auxiliary wire 41 is electrically connected to the positive wire 31. The distal end 411 of the positive auxiliary wire 41 is disposed in the protective capsule 242. The proximal end of the negative auxiliary wire 42 is electrically connected to the negative wire 32. The distal end 421 of the negative auxiliary wire 42 is disposed in the protective capsule 242. The distal end 411 of the positive auxiliary wire 41 is spaced a distance from the distal end 421 of the negative auxiliary wire 42. The distal end 411 of the positive auxiliary wire 41 is not in direct contact with the distal end 421 of the negative auxiliary wire 42. In a preferred embodiment, the proximal end of the positive auxiliary wire 41 is electrically connected to the proximal end of the positive wire 31, and the proximal end of the negative auxiliary wire 42 is electrically connected to the proximal end of the negative wire 32.

[0087] In one embodiment, a catheter connecting end 5 is provided on the cryoablation device 1, one end of the catheter connecting end 5 is fixedly connected to the gas circuit module 13, and the other end of the catheter connecting end 5 is connected to the catheter handle 22 through a flexible connecting tube 21, and the air inlet pipe 25, the air return pipe 26, the positive electrode wire 31, the negative electrode wire 32, the positive electrode auxiliary wire 41 and the negative electrode auxiliary wire 42 pass through the lumen of the flexible connecting tube 21 and the catheter connecting end 5 to be connected to the cryoablation device 1.

[0088] In a preferred embodiment, the conduit connecting end 5 is threadedly connected to the gas circuit module 13 .

[0089] In one embodiment, the proximal end of the air inlet pipe 25 is connected to the air circuit module 13, the distal end 251 of the air inlet pipe 25 is disposed in the distal end of the freezing capsule 241, the proximal end of the return air pipe 26 is connected to the air circuit module 13, and the distal end 261 of the return air pipe 26 is disposed in the proximal end of the freezing capsule 241.

[0090] In a preferred embodiment, the proximal end of the air inlet pipe 25 and the proximal end of the air return pipe 26 are both snap-connected to the air circuit module 13 .

[0091] In one embodiment, a guidewire lumen 27 is disposed in the catheter elongated shaft 23 , and the guidewire lumen 27 extends out of the distal end of the catheter elongated shaft 23 . The distal end of the freezing unit 24 is fixedly connected to the guidewire lumen 27 .

[0092] During the operation, first start the cryoablation device 1, and operate the cryoablation catheter 2 to enter the patient's body. After being filled with refrigerant, the balloon 24 is deployed in the patient's body. When there is no liquid intrusion, there is no conductive medium between the distal end 411 of the positive auxiliary wire 41 and the distal end 421 of the negative auxiliary wire 42, and they cannot be connected. When liquid intrusion occurs, due to the conductivity of the liquid, the distal end 411 of the positive auxiliary wire 41 and the distal end 421 of the negative auxiliary wire 42 are connected, resulting in the potential measured by the thermocouple not being at the temperature measurement point where the distal end 311 of the positive wire 31 of the thermocouple and the distal end 321 of the negative wire 32 of the thermocouple are connected, but at the connection between the positive wire 31 and the positive auxiliary wire 41 and the connection between the negative wire 32 and the negative auxiliary wire 42. The electric potential returns to the control module 12, is processed by the control module 12, and is finally fed back to the human-computer interaction module 11. At the same time, the control module 12 is operated to stop the gas circuit module 13 from operating, so as to avoid further aggravation of the problem of liquid intrusion.

[0093] The present application improves the thermocouple that is usually set in the catheter, connects the proximal ends of the positive auxiliary wire and the negative auxiliary wire to the thermocouple, and uses the conductivity of metal to detect the liquid through two wires, avoiding the placement of photoelectric sensors or liquid sensors. Therefore, there is no need to add a power supply line in the catheter, which simplifies the structure and saves space inside the catheter lumen. It not only avoids electric shock injuries to patients in extreme cases, but also further reduces the size of the catheter, improves the safety of interventional catheters, increases the flexibility of catheters, can adapt to different vascular conditions, and expands the scope of use. In addition, the existing photoelectric sensor requires a power supply line and a signal line, which requires at least four wires. Adding four wires in the narrow space of the catheter lumen is likely to affect its performance. The present application reduces the number of wires that need to be connected to the control module at the catheter connector end, improving ease of use and stability.

[0094] Embodiment 4

[0095] The difference between this embodiment and the third embodiment is that the structure of the safety device 4 is different. Fig.13 and Fig.14 As shown, the safety device 4 is openings 43 and 44 respectively arranged on the distal parts of the positive wire 31 and the negative wire 32, and the openings 43 and 44 are arranged on the distal side of the liquid sealing mechanism 28. The openings 43 and 44 expose the conductive metal wires in the positive wire 31 and the negative wire 32, and the exposed conductive metal wires of the positive wire 31 and the negative wire 32 are not in direct contact.

[0096] In one embodiment, a catheter connection end 5 is provided on the cryoablation device, one end of the catheter connection end 5 is fixedly connected to the gas circuit module 13, and the other end of the catheter connection end 5 is connected to the catheter handle 22 through a flexible connecting tube 21, and the air inlet pipe 25, the air return pipe 26, the positive lead 31 and the negative lead 32 pass through the lumen of the flexible connecting tube 21 and the catheter connection end 5 is connected to the cryoablation device 1. In a preferred embodiment, the catheter connection end 5 is threadedly connected to the gas circuit module 13.

[0097] In one embodiment, the proximal end of the air inlet pipe 25 is connected to the air circuit module 13, and the distal end of the air inlet pipe 25 is disposed in the distal end of the freezing capsule 241; the proximal end of the return air pipe 26 is connected to the air circuit module 13, and the distal end of the return air pipe 26 is disposed in the proximal end of the freezing capsule 241.

[0098] In a preferred embodiment, the proximal end of the air inlet pipe 25 and the proximal end of the air return pipe 26 are both snap-connected to the air circuit module 13 .

[0099] In this embodiment, no wire is attached to the positive wire 31 of the thermocouple 3 and the negative wire 32 of the thermocouple 3. Instead, two openings are set at a certain distance from the distal measurement point of the thermocouple 3 to the proximal direction. The two openings expose the conductive metal wire of the positive wire 31 and the conductive metal wire of the negative wire 32 by cutting the outer skin of the positive wire 31 and the negative wire 32. When there is no liquid in the cavity, the exposed positive conductive metal wire and the negative conductive metal wire do not come into contact, and the potential measured by the thermocouple 3 is still the potential of the measurement point. When liquid invades, the liquid submerges the opening, and the conductivity of the liquid makes the exposed positive conductive metal wire and the negative conductive metal wire conductive, thereby forming a second temperature measurement point at this location. The thermocouple potential is actually the temperature of the second temperature measurement point. The potential of the second temperature measurement point is actually different from the potential of the first temperature measurement point, and the difference can be used to determine liquid invasion. The measured potential is transmitted to the control module 12, processed by the control module 12, and finally fed back to the human-computer interaction module 11. At the same time, the control module 12 is operated to stop the gas circuit module 13 to avoid further aggravation of the problem of liquid intrusion.

[0100] The present application uses only one thermocouple to complete the liquid detection function, optimizes the inner size of the catheter, improves the safety of the interventional catheter, increases the flexibility of the catheter, and expands the adaptability to different vascular conditions.

[0101] Finally, it should be noted that the above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A cryoablation system for monitoring fluid flow status, comprising a cryoablation device and a cryoablation catheter, wherein the cryoablation device comprises a human-machine interaction module, a control module, and an air circuit module, wherein the human-machine interaction module is electrically connected to the control module, the control module is electrically connected to the air circuit module, and the air circuit module is connected to the cryoablation catheter, characterized in that: The cryoablation catheter comprises a slender catheter shaft, a catheter handle arranged at the proximal end of the slender catheter shaft, a freezing unit arranged at the distal end of the slender catheter shaft, an air inlet pipe and an air return pipe arranged in the cavity of the slender catheter shaft, the air inlet pipe and the air return pipe are in fluid communication with the inner cavity of the freezing unit, a gas flow state monitoring sensor is arranged at the proximal end of the air return pipe, and a liquid blocking mechanism is arranged in the distal end of the slender catheter shaft, the liquid blocking mechanism has a hydrophobic microporous structure, and the surface properties and size structure of the liquid blocking mechanism meet the following quantitative relationship: P<λ2cos(π-θ) / r Where P is the absolute pressure of the liquid at the leakage point, λ is the surface tension coefficient, r is the equivalent hydraulic radius of the pore, and θ is the contact angle of the liquid on the pore wall.

2. The cryoablation system for facilitating fluid flow status monitoring according to claim 1, characterized in that: A negative pressure suction pump is arranged at the proximal end of the air return pipe, and the gas flow state monitoring sensor is arranged at the inlet of the negative pressure suction pump.

3. The cryoablation system for facilitating fluid flow status monitoring according to claim 1, characterized in that: The gas flow state monitoring sensor is a pressure sensor, a flow sensor or a flow velocity sensor or a combination thereof.

4. The cryoablation system for facilitating fluid flow status monitoring according to claim 1, characterized in that: The liquid sealing mechanism is a hydrophobic coating coated on the inner wall of the slender shaft of the catheter and the outer walls of the air inlet pipe and the air return pipe, or the liquid sealing mechanism is arranged in the space defined by the inner wall of the slender shaft of the catheter and the outer walls of the air inlet pipe and the air return pipe, the liquid sealing mechanism is an array with a hydrophobic microporous structure, or the liquid sealing mechanism is a hydrophobic thread placed in the gap between the inner wall of the slender shaft of the catheter and the outer walls of the air inlet pipe and the air return pipe.

5. The cryoablation system for facilitating fluid flow status monitoring according to claim 4, characterized in that: The liquid blocking mechanism is a combination of a hydrophobic coating, a hydrophobic thread, and a hydrophobic microporous structure.

6. The cryoablation system for facilitating fluid flow status monitoring according to any one of claims 1 to 5, characterized in that: The liquid sealing mechanism has a millimeter-level, micrometer-level or nanometer-level pore structure, the liquid sealing mechanism is a honeycomb array, or the hydrophobic microporous structure of the liquid sealing mechanism is an ordered array or a disordered array, and the liquid sealing mechanism can prevent liquid from passing through but allow gas to pass through.

7. The cryoablation system for facilitating fluid flow status monitoring according to claim 6, characterized in that: The freezing unit includes a freezing bladder and a protective bladder, the protective bladder is wrapped outside the freezing bladder, the air inlet pipe and the air return pipe are connected to the inner cavity fluid of the freezing bladder, a thermocouple is also arranged in the slender shaft of the catheter, the thermocouple is connected to the control module wire, the thermocouple includes a positive wire and a negative wire, the distal end of the positive wire and the distal end of the negative wire are both arranged in the protective bladder, the distal end of the positive wire is connected to the distal end of the negative wire, and a safety device is arranged on the thermocouple.

8. The cryoablation system for facilitating fluid flow status monitoring according to claim 7, characterized in that: The safety device consists of a positive electrode accessory wire and a negative electrode accessory wire, the proximal end of the positive electrode accessory wire is electrically connected to the positive electrode wire, the distal end of the positive electrode accessory wire is arranged in the protective capsule, the proximal end of the negative electrode accessory wire is electrically connected to the negative electrode wire, the distal end of the negative electrode accessory wire is arranged in the protective capsule, and the distal end of the positive electrode accessory wire is not in direct contact with the distal end of the negative electrode accessory wire.

9. The cryoablation system for facilitating fluid flow status monitoring according to claim 7, characterized in that: The safety device is an opening respectively arranged on the distal parts of the positive wire and the negative wire, and the opening is arranged on the distal side of the liquid sealing mechanism. The opening exposes the conductive metal wires in the positive wire and the negative wire, and the exposed conductive metal wires of the positive wire and the negative wire are not in direct contact.

10. The cryoablation system for facilitating fluid flow status monitoring according to claim 1, characterized in that: A water vapor sensor is arranged in the cryoablation system. The water vapor sensor is in fluid communication with the elongated shaft of the catheter and is electrically connected to the control module.

11. The cryoablation system for facilitating fluid flow status monitoring according to claim 10, characterized in that: A negative pressure pump is arranged inside the cryoablation device, the negative pressure pump is in fluid communication with the elongated shaft of the catheter, the negative pressure pump is electrically connected to the control module, and the water vapor sensor is arranged at the inlet end side of the negative pressure pump.

12. The cryoablation system for facilitating fluid flow status monitoring according to claim 11, characterized in that: A water molecule isolator and a stop valve are arranged between the water vapor sensor and the negative pressure pump, and the stop valve is electrically connected to the control module.

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