CN110882051B - A cryoablation system for convenient fluid flow state monitoring - Google Patents

Abstract

The application relates to a cryoablation system convenient for monitoring fluid flow state, which consists of a cryoablation device and a cryoablation catheter, wherein the cryoablation device comprises a man-machine interaction module, a control module and an air channel module, the man-machine interaction module is electrically connected with the control module, the control module is electrically connected with the air channel module, the air channel module is connected with the cryoablation catheter, the cryoablation catheter comprises a catheter slender shaft, a catheter handle arranged at the proximal end of the catheter slender shaft, a freezing unit arranged at the distal end of the catheter slender shaft, an air inlet pipe and an air return pipe arranged in the cavity of the catheter slender shaft, the air inlet pipe and the air return pipe are in fluid communication with the 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 the safety risk of the catheter by arranging the multiple safety devices, and greatly reduces the risk of the catheter in the application process.

Description

Cryoablation system convenient for monitoring fluid flow state

Technical Field

The application belongs to the field of minimally invasive interventional therapy, and particularly relates to a cryoablation system convenient for monitoring a fluid flow state.

Background

Cryoablation is a new technique in the treatment of cardiac arrhythmias. The principle is that the heat of the tissue is taken away through the endothermic evaporation of the liquid refrigerant, so that the temperature of the target ablation part is reduced, and abnormal cell tissues are destroyed, thereby achieving the purpose of treatment. Catheters used in cryoablation all need to enter the interior of the body and penetrate deep into the focal site. Any cryoablation system presents a certain safety risk, and how to effectively detect and prevent the associated risks is a major problem that needs to be addressed in the art. For the cryoablation process, the safety risks are mainly two, namely, firstly, the potential safety hazard is formed by the balloon running under higher pressure due to the congestion of a catheter gas loop, and secondly, the safety risk is formed by the damage of a catheter, so that human blood enters the catheter to cause partial blood loss of a patient. Although the risk occurrence probability is extremely low, once the risk occurrence is caused, the health and even life safety of a patient are adversely affected. Therefore, a safe and effective detection device is needed to accurately and effectively predict and timely prevent risks.

Aiming at the first safety risk, the existing detection system generally judges whether a gas loop of a conduit is blocked by detecting the pressure or the flow of the inlet gas, however, the detection by the method has the defect of detection reaction lag, under the condition that the gas loop is blocked, the balloon of the freezing unit can generate an overpressure risk within two seconds, and the gas loop can be effectively detected and the gas source can be closed after the gas loop is blocked for 2-3 seconds or even longer, so that obvious potential safety hazards exist. Therefore, it is highly desirable to provide a method for detecting a gas loop blockage with a quicker response, which can realize the accurate detection and real-time feedback of the gas loop blockage at the moment, and avoid the risk of balloon overpressure.

For the second safety risk, the existing solutions are mainly to detect leaking liquid (typically patient blood) by arranging a photoelectric sensor inside the catheter. The photoelectric sensor is formed by mounting the transmitter and the receiver face to face on both sides of a length of transparent conduit. When no obstruction exists, the light source of the emitter irradiates the receiver through the transparent conduit, and after the receiver receives the light, the unobstructed foreign matter is judged. When the liquid is accidentally immersed, the light source of the emitter is blocked partially or totally, and the receiver receives part of the light or cannot receive the light, namely, the foreign matter is judged, namely, the accidental liquid is immersed. By this method detection of fluid leakage it is inevitable that fluid (typically patient blood) will enter the catheter, thereby affecting patient health. In addition, since the photoelectric sensor needs to provide a transmitter and a receiver in the catheter, the outer diameter of the catheter is inevitably increased, and there is a problem in that it is impossible to adapt to a part of the blood vessel. Thirdly, the sensor needs a power supply circuit and a signal circuit, at least four wires are required to be arranged in the catheter, and the performance of the sensor is possibly influenced by adding the four wires in a narrow space of the catheter. Therefore, there is an urgent need to provide a safety device capable of detecting leakage of liquid into a catheter, which is simple in structure, does not increase the size of the catheter, and avoids the risk of blood loss of a patient caused by liquid entering the catheter.

Disclosure of Invention

The application aims to overcome the defects of the prior art, designs a cryoablation system which is convenient for monitoring the fluid flow state, the cryoablation system effectively detects and prevents the safety risk of the catheter by arranging the multiple safety devices, and greatly reduces the risk in the application process of the cryoablation system.

The application aims at realizing the following technical scheme:

The cryoablation system comprises cryoablation equipment and a cryoablation catheter, wherein the cryoablation equipment comprises a man-machine interaction module, a control module and an air channel module, the man-machine interaction module is electrically connected with the control module, the control module is electrically connected with the air channel module, the air channel module is connected with the cryoablation catheter, the cryoablation catheter comprises a catheter slender shaft, a catheter handle arranged at the proximal end of the catheter slender shaft, a freezing unit arranged at the distal end of the catheter slender shaft, an air inlet pipe and an air return pipe arranged in a cavity of the catheter slender shaft, the air inlet pipe and the air return pipe are in fluid communication with the cavity of the freezing unit, and a gas flow state monitoring sensor is arranged at the proximal end of the air return pipe.

The aim of the application can be achieved by the following technical scheme:

In one embodiment, a negative pressure getter pump is provided at the proximal end of the muffler, and the gas flow state monitoring sensor is provided at an inlet of the negative pressure getter pump.

In a preferred embodiment, the gas flow state monitoring sensor is a pressure sensor, a flow sensor or a flow rate sensor.

In one embodiment, a liquid blocking mechanism is disposed within the distal end of the catheter elongate shaft, the liquid blocking mechanism having a hydrophobic microporous structure.

In a preferred embodiment, the surface properties and dimensional structure of the liquid blocking mechanism correspond to the following quantitative relationship:

Where P is the absolute pressure of the fluid at the leak point, λ is the surface tension coefficient, r is Kong Dangliang hydraulic radius, and Ѳ is the contact angle of the fluid on the pore wall. In calculation, r is the pore radius for circular pores, and the equivalent hydraulic radius for non-circular or other irregular pore structures such as square, triangular, etc.

In a preferred embodiment, the liquid blocking mechanism is a hydrophobic coating applied to the inner wall (inner surface) of the catheter elongate shaft and the outer wall (outer surface) of the air inlet tube and the air return tube.

In a preferred embodiment, the liquid blocking mechanism is disposed within a space defined by an inner wall of the elongate shaft of the catheter and an outer wall of the air inlet tube and the air return tube, the liquid blocking mechanism being an array having a hydrophobic microporous structure.

In a preferred embodiment, the liquid blocking mechanism is a hydrophobic wire placed in a gap between an inner wall of the catheter elongate shaft and an outer wall of the air inlet tube and the air return tube.

In a preferred embodiment, the liquid blocking mechanism is a combination of a hydrophobic coating, a hydrophobic thread, a hydrophobic microporous structure. The combination comprises any two structures being matched or three structures being combined together.

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

In a preferred embodiment, the liquid blocking means is a honeycomb-like array, or the hydrophobic microporous structure of the liquid blocking means is an ordered array or an unordered array, the liquid blocking means being capable of blocking the passage of liquid while allowing the passage of gas.

In one embodiment, a water vapor sensor is disposed within the cryoablation system, the water vapor sensor in fluid communication with the catheter elongate shaft, the water vapor sensor in electrical communication with the control module.

In a preferred embodiment, the cryoablation device is connected to the catheter handle by a flexible connection tube, and the water vapor sensor is disposed inside the catheter handle, inside the flexible connection tube, or inside the cryoablation device.

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

In a preferred embodiment, a negative pressure pump is provided inside the cryoablation apparatus, the negative pressure pump being in fluid communication with the catheter elongate shaft, the negative pressure pump being electrically connected to a control module, the water vapor sensor being provided on an inlet end side of the negative pressure pump.

In a preferred embodiment, a water molecule separator is provided between the water vapor sensor and the negative pressure pump.

In a preferred embodiment, a shut-off valve is provided between the water vapor sensor and the negative pressure pump, said shut-off valve being electrically connected to the control module.

In one embodiment, the refrigeration unit includes a refrigeration bladder and a protection bladder, the protection bladder is wrapped around the refrigeration bladder, and the air inlet tube and the air return tube are in fluid communication with the interior cavity of the refrigeration bladder.

In a preferred embodiment, a thermocouple is further arranged in the catheter slender shaft, the thermocouple is connected with the control module through wires, the thermocouple comprises an anode wire and a cathode wire, the distal end of the anode wire and the distal end of the cathode wire are both arranged in the protection capsule, the distal end of the anode wire is connected with the distal end of the cathode wire, and a safety device is arranged on the thermocouple.

In a preferred embodiment, the safety device is composed of a positive auxiliary wire and a negative auxiliary wire, the proximal end of the positive auxiliary wire is electrically connected with the positive wire, the distal end of the positive auxiliary wire is disposed in the protective capsule, the proximal end of the negative auxiliary wire is electrically connected with the negative wire, the distal end of the negative auxiliary wire is disposed in the protective capsule, and the distal end of the positive auxiliary wire is spaced apart from the distal end of the negative auxiliary wire by a distance that is, the distal end of the positive auxiliary wire is not in direct contact with the distal end of the negative auxiliary wire.

In a preferred embodiment, a catheter connection end is provided on the cryoablation device, one end of the catheter connection end is fixedly connected with the air path module, the other end of the catheter connection end is connected with the catheter handle through a flexible connection pipe, and the air inlet pipe, the air return pipe, the positive electrode lead wire, the negative electrode lead wire, the positive electrode auxiliary lead wire and the negative electrode auxiliary lead wire penetrate through a lumen of the flexible connection pipe and the catheter connection end is connected with the cryoablation device.

In a preferred embodiment, the conduit connection end is threadably connected to the gas circuit module.

In a preferred embodiment, the proximal end of the air inlet tube is connected to the air passage module, the distal end of the air inlet tube is disposed within the distal end of the freezing bladder, the proximal end of the air return tube is connected to the air passage module, and the distal end of the air return tube is disposed within the proximal end of the freezing bladder.

In a preferred embodiment, the proximal end of the air inlet pipe and the proximal end of the air return pipe are both in snap connection with the air circuit module.

In a preferred embodiment, the safety device is an opening provided on distal end portions of the positive electrode lead and the negative electrode lead, respectively, the opening being provided on a distal end side of the liquid blocking mechanism, the opening exposing conductive wires within the positive electrode lead and the negative electrode lead, the conductive wires exposed by the positive electrode lead and the negative electrode lead not being in direct contact.

In a preferred embodiment, a catheter connection end is provided on the cryoablation device, one end of the catheter connection end is fixedly connected with the air path module, the other end of the catheter connection end is connected with the catheter handle through a flexible connecting pipe, and the air inlet pipe, the air return pipe, the positive electrode lead wire and the negative electrode lead wire penetrate through a lumen of the flexible connecting pipe and the catheter connection end is connected with the cryoablation device.

Compared with the prior art, the application has the advantages that:

1. The application is provided with a gas flow state monitoring sensor at the proximal end of the muffler. Existing catheter gas circuit occlusion detection is typically performed by detecting the inlet or balloon internal pressure, with the risk disadvantage of reaction hysteresis leading to excessive instantaneous pressure within the balloon. According to the application, the gas flow state monitoring sensor is arranged at the proximal end of the muffler, so that the non-delay immediate monitoring of the blocking condition of the gas loop can be realized, the condition that the internal pressure of the balloon of the refrigerating unit exceeds the rated requirement value can be avoided, and the safety is obviously superior to that of the existing product.

2. The application designs the liquid blocking mechanism in the far end of the slender shaft of the catheter, which can automatically intercept the leaked liquid from entering the catheter by utilizing the self surface tension of the liquid. The existing liquid leakage detection device for the guide pipe can detect liquid after a large amount of liquid enters the guide pipe through a photoelectric sensor or other liquid sensors, and cannot effectively detect the liquid before the liquid enters the guide pipe, so that the technical problem that the liquid enters the guide pipe after leakage cannot be solved. The application is based on the physical characteristics that the surface tension of the liquid passing through the pores with different surface characteristics has different directivities, and by arranging the hydrophobic pore structure, the liquid is automatically limited to flow by utilizing the reverse surface tension of the liquid, so that the liquid is successfully locked, and the leaked liquid is prevented from entering the catheter, thereby preventing the blood loss of a patient caused by the leakage of the liquid in the catheter.

3. The application is provided with the steam sensor in the cryoablation system, can effectively intercept liquid from entering the catheter and effectively detect liquid leakage, and solves the problem that liquid leakage cannot be effectively detected while liquid leakage is prevented from entering the catheter. The liquid blocking mechanism arranged in the conduit can block liquid from entering the conduit and allow water vapor gas molecules to pass through, so that the liquid leakage detection can be realized by arranging the water vapor sensor in the external area or the equipment end of the conduit and detecting the content of the water vapor molecules. This approach does not increase the size of the catheter entering the body segment, as the liquid blocking mechanism need only be coated or filled within the catheter elongate shaft.

4. The photoelectric sensor adopted by the liquid leakage detection system of the existing part of the catheter needs a power supply circuit and a signal circuit, at least four wires are needed, and the size of the catheter lumen is increased by adding the four wires in a narrow space of the catheter lumen, so that the size of a wound is increased, and the usability of the catheter is affected. The application does not need to arrange a sensor element, so that a power supply circuit is not needed to be added in the catheter, and electric shock injury to a patient possibly caused under extreme conditions is avoided. In addition, compared with the method of arranging the sensor inside, the size of the catheter can be further reduced, the safety of the interventional catheter is improved, the flexibility of the catheter is improved, the catheter can adapt to different vascular conditions, and the application range is enlarged.

5. According to the application, the thermocouples which are usually arranged in the catheter are improved, the detection of liquid is realized through two wires by utilizing the metal conductivity, the placement of a photoelectric sensor or a liquid sensor is avoided, the structure is simplified, the internal space of the lumen of the catheter is saved, and compared with the method of arranging the sensor in the lumen of the catheter, the size of the catheter is reduced.

Drawings

Fig. 1 is a schematic diagram of the overall structure of a cryoablation system of the present application for facilitating fluid flow condition monitoring.

Fig. 2 is a schematic structural view of a catheter gas circuit blockage detection device of a cryoablation apparatus in accordance with one embodiment of the present application.

Fig. 3a to 3c are schematic diagrams illustrating a determination of a blockage of a gas circuit in a conduit according to an embodiment of the application.

Fig. 4 is a schematic structural view of the distal end of a cryoablation catheter in accordance with one embodiment of the application.

Fig. 5 is a schematic view showing the structure of a first embodiment of a liquid blocking mechanism according to an embodiment of the present application.

Fig. 6 is a schematic structural view of a second embodiment of a liquid blocking mechanism according to an embodiment of the present application.

Fig. 7 is a schematic view showing the structure of a third embodiment of the liquid blocking mechanism according to an embodiment of the present application.

FIG. 8 is a schematic illustration of liquid force analysis in a single aperture of a liquid blocking mechanism according to one embodiment of the application.

Fig. 9 is a schematic view of an embodiment of the cryoablation system of the present application wherein a water vapor sensor is provided.

Fig. 10 is a schematic view of another embodiment of the cryoablation system of the application wherein a water vapor sensor is provided.

FIG. 11 is a schematic view of the structure of a catheter connection end according to an embodiment of the present application.

Fig. 12 is a schematic view of the structure of the distal end of a cryoablation catheter in accordance with another embodiment of the application.

Fig. 13 is a schematic structural view of a catheter connection end according to another embodiment of the present application.

Fig. 14 is a schematic structural view of the distal end of a cryoablation catheter in accordance with one embodiment of the application.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application will be further described in detail below by referring to the accompanying drawings and examples.

Example 1

As shown in fig. 1 and 2, a cryoablation system convenient for monitoring fluid flow state is composed of a cryoablation device 1 and a cryoablation catheter 2, wherein the cryoablation device comprises a man-machine interaction module 11, a control module 12 and a gas circuit module 13, the man-machine interaction module 11 is electrically connected with the control module 12, the control module 12 is electrically connected with the gas circuit module 13, the cryoablation catheter 2 comprises 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, the air inlet pipe 25 and the air return pipe 26 are in fluid communication with the inner cavity of the freezing unit 24, and a gas flow state monitoring sensor 15 is arranged at the proximal end of the air return pipe.

In one embodiment, as shown in fig. 2, a negative pressure suction pump 14 is provided at the proximal end of the muffler, 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 rate sensor. When the pressure sensor detects that the pressure, flow or flow speed of the gas drops by a certain ratio (recommended value is 30%/s), the blockage situation of the gas loop of the catheter can be judged, the control module 12 immediately closes the air inlet valve 16 of the catheter, the condition that the pressure in the balloon is too high can be avoided, and the setting of the structure can greatly reduce the operation risk.

As shown in fig. 3a to 3c, the fluid transfer is a point-to-point sequential transfer process, where the last 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 the following fluids. When the fluid circuit is blocked, the flow source of the whole fluid circuit does not instantaneously and completely become 0, but the fluid flow rate at the blocking point is first changed to 0, so that the flow rate of the whole fluid circuit does not instantaneously and completely become 0. Therefore, the fluid flow state monitoring point is arranged at the proximal end of the muffler (such as the monitoring point 1), the blocking state of the fluid loop can be monitored more quickly, the air inlet valve 16 is closed timely, and the internal pressure of the balloon is prevented from being too high. In the prior art, whether the balloon is internally over-pressurized or not is judged by detecting the pressure in the balloon through a pressure sensor or the blocking condition of a fluid circuit is judged through a flow sensor arranged on an air inlet pipeline. If the occlusion point is at the end of the fluid circuit and the monitoring point is before the occlusion point (e.g., monitoring point 2), a significant monitoring hysteresis will occur, and during the period from the onset of occlusion (time point a) to the hysteresis monitoring (time point B), fluid continues to flow and accumulate inside the balloon due to the inertial effects of the fluid transfer, while the flow resistance increases to infinity due to occlusion at the end of the fluid circuit, and the fluid flow from the balloon is rapidly reduced to approximately zero, so that the pressure inside the balloon increases significantly (the rate of increase is related to the pressure of the air source) within 1-2 seconds of the occurrence of the occlusion of the fluid circuit. Even if the balloon internal pressure is detected directly, a monitoring lag will occur as long as the occlusion point is located in the post-balloon fluid circuit. According to the application, the monitoring point is arranged at the proximal end of the muffler, any position of the whole catheter fluid loop is blocked, the flow state information such as the flow speed, the flow rate or the pressure of the monitoring point is 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, and the pressure rise in the balloon can be avoided, so that the operation risk is greatly reduced.

Example two

This embodiment differs from the first embodiment in that a liquid occlusion mechanism 28 is provided in the distal end of the catheter elongate shaft 23 and a water vapor sensor 29 is provided in the cryoablation system, as shown in fig. 1 and 4. The plugging structure 28 has a hydrophobic microporous structure (as shown in fig. 5), the liquid plugging mechanism 28 is disposed in a space defined by the inner wall of the catheter elongated shaft 23 and the outer walls of the air inlet pipe 25 and the air return pipe 26, and the liquid plugging mechanism 28 is an array 281 having a hydrophobic microporous structure. In one embodiment, the liquid blocking mechanism 28 has a millimeter-scale, micrometer-scale, or nanometer-scale pore structure. In a preferred embodiment, the liquid blocking mechanism 28 is a honeycomb-like array, or the hydrophobic microporous structure of the liquid blocking mechanism 28 is an ordered array or an unordered array, the liquid blocking mechanism 28 being capable of blocking the passage of liquid while allowing the passage of gas. The application designs a liquid blocking mechanism 28 in the distal end of the catheter elongate shaft, which can automatically intercept leaked liquid from entering the catheter by utilizing the self surface tension of the liquid. The existing liquid leakage detection device for the guide pipe can detect liquid after a large amount of liquid enters the guide pipe through a photoelectric sensor or other liquid sensors, and cannot effectively detect the liquid before the liquid enters the guide pipe, so that the technical problem that the liquid enters the guide pipe after leakage cannot be solved. Based on the physical characteristics that the surface tension of the liquid passing through the pores with different surface characteristics has different directivities, the application utilizes the reverse surface tension of the liquid to automatically limit the flow of the liquid by arranging the hydrophobic pore structure, successfully locks the liquid naturally, and prevents the leaked liquid from entering the catheter, thereby preventing the blood loss of a patient caused by the leakage of the liquid in the catheter.

In order to effectively inhibit blood from passing through the liquid occlusion mechanism 28, the surface properties and dimensional structure of the liquid occlusion mechanism 28 satisfy the following quantitative relationships:

(1)

Where P is the absolute pressure of the liquid at the leak point, lambda is the surface tension coefficient, r is the pore radius, Ѳ is the contact angle of the liquid on the pore wall.

The theoretical derivation process is as follows (see fig. 8):

surface tension of liquid (2)

The surface tension in the y-direction is:

(3)

Assuming that the leak fluid absolute pressure is P, the axial force generated by the fluid pressure at the aperture inlet can be expressed as:

(4)

the liquid pressure at the point of leakage produces an axial force at the aperture entrance that is less than the surface tension component in the y-direction, i.e When the liquid cannot overcome the surface tension effect, the liquid can not pass through the pores, and the liquid can be effectively intercepted.

Bringing formulae 3-4 into availability:

(5)

the above can also be expressed as (1)

Thus, as long as the inside diameter r and the surface tension coefficient λ of the hydrophobic pore liquid plugging mechanism 28 and the contact angle Ѳ with the plugged liquid conform to the above formulas, the liquid will be effectively plugged.

The above formula is also true for non-circular or other irregular pore structures such as square, triangular, etc., where r in formula 1 is the equivalent hydraulic radius of the pore structure.

In one embodiment, as shown in fig. 4, the freezing unit 24 includes a freezing bladder 241 and a protecting bladder 242, the protecting bladder 242 is wrapped around the freezing bladder 241, and the air inlet pipe 25 and the air return pipe 26 are in fluid communication with the inner cavity of the freezing bladder 241. During operation of the cryoablation system, if the protective balloon 242 is broken, blood in the body will enter the catheter elongate shaft 23 through the hole, and the blood entering the catheter elongate shaft 23 will generate a significant surface tension at the inlet of the liquid blocking mechanism 28 opposite to the flow direction, inhibiting its flow.

In one embodiment, as shown in fig. 6, the liquid blocking mechanism 28 is a hydrophobic coating 282 applied to the inner wall (inner surface) of the elongate shaft 23 of the catheter and to the outer surface of the air inlet tube 25 and the outer surface of the air return tube 26 to provide a liquid blocking seal.

In one embodiment, as depicted in FIG. 7, the liquid blocking mechanism 28 is a hydrophobic wire 283 that is packed within the space between the inner wall of the catheter elongate shaft 23 and the outer wall of the air inlet tube 25 and the air return tube 26, the hydrophobic wire 283 may be millimeter-sized, micron-sized, or nano-sized, the diameter of the hydrophobic wire 283 may be uniform or non-uniform, and the hydrophobic pore structure formed between the hydrophobic wires 283 may create a reverse surface tension to the liquid passing therethrough, thereby achieving liquid blocking. The higher the packing density of the hydrophobic threads 283, the smaller the thread diameter and accordingly the smaller the equivalent hydraulic radius r, the better the liquid blocking effect, as can be seen from equation 1. The method is more convenient to realize by a hydrophobic thread filling mode, and the processing cost is lower.

In a preferred embodiment, the hydrophobic coating 282 is used in combination with the hydrophobic threads 283, the hydrophobic microporous structure 281, or in combination of two or three, to enhance the liquid blocking effect.

In one embodiment, as shown in fig. 1, a water vapor sensor 29 is disposed within the cryoablation system, the water vapor sensor 29 being in fluid communication with the catheter elongate shaft 23, the water vapor sensor 29 being electrically connected to the control module 12. In a preferred embodiment, the cryoablation device 1 is connected to the catheter handle 22 by a flexible connection tube 21, and the water vapor sensor 29 is disposed inside the catheter handle 22, inside the flexible connection tube 21, or inside the cryoablation device 1. When the catheter is damaged to cause leakage of fluid, external blood enters the catheter, although liquid cannot flow into the catheter due to the action of surface tension opposite to the flowing direction, the partial pressure of vapor in the catheter is far lower than the partial pressure of vapor in a saturated state, the liquid is rapidly evaporated and diffused, so that a small amount of vapor can smoothly enter the catheter through the liquid blocking mechanism 28, and is effectively detected by the vapor sensor 29 arranged in the catheter handle 22, and when the vapor sensor 29 detects the vapor, an electric signal is transmitted to the control module 12, and the control module 12 immediately gives feedback to send out a corresponding instruction to stop operation. As shown in fig. 9, the control module 12 closes the catheter inlet valve 16, opens the negative pressure suction pump 14, and the negative pressure suction pump 14 is disposed at the proximal end of the catheter's muffler 26 for removing gas from the catheter's fluid circulation circuit, reducing the risk of gas entering the blood through the catheter's break. The application is provided with the steam sensor in the cryoablation system, can effectively intercept liquid from entering the catheter and effectively detect liquid leakage, and solves the problem that liquid leakage cannot be effectively detected while liquid leakage is prevented from entering the catheter. The liquid blocking mechanism arranged in the conduit can block liquid from entering the conduit and allow water vapor gas molecules to pass through, so that the liquid leakage detection can be realized by arranging the water vapor sensor in the external area or the equipment end of the conduit and detecting the content of the water vapor molecules. This approach does not increase the size of the catheter entering the body segment, as the liquid blocking mechanism need only be coated or filled within the catheter elongate shaft.

In one embodiment, the water vapor sensor 29 is a humidity sensor, and the water vapor level in the conduit is determined by humidity change monitoring. As shown in fig. 9, a negative pressure pump 17 is provided inside the cryoablation apparatus 1, the negative pressure pump 17 is in fluid communication with the catheter elongate shaft 23 for maintaining the pressure inside the catheter elongate shaft 23 below the external blood pressure, the negative pressure pump 17 is electrically connected to the control module 12, and the water vapor sensor 29 is provided at the inlet end side of the negative pressure pump 17. The negative pressure pump 17 can maintain the negative pressure environment inside the catheter, and avoid the pressure inside the catheter to be higher than the external blood pressure. When the catheter leaks, the pressure inside the catheter is lower than the pressure of the external blood, so that the risk of air embolism caused by air entering the blood can be avoided. When the system detects a catheter leak, the control module 12 turns off the negative pressure pump 17, avoiding the negative pressure pump 17 from continuously inhaling to cause blood loss.

In one embodiment, as shown in fig. 10, a shut-off valve 19 is provided between the water vapor sensor 29 and the negative pressure pump 17, and the shut-off valve 19 is electrically connected to the control module 12. In general, after the negative pressure pump 17 is closed, the rotor of the negative pressure pump rotates for a certain time under the action of inertia, in order to avoid the blood loss caused by the inertia negative pressure, the system is provided with the stop valve 19 in front of the negative pressure pump 17, and when the system detects the leakage of the catheter fluid, the stop valve 19 is closed timely, so that the gas can be prevented from continuously entering the system, and the blood loss is reduced. In one embodiment, a water molecule separator 18 is provided between the water vapor sensor 29 and the negative pressure pump 17. The water molecule separator 18 can prevent water vapor molecules from passing through, but allows other gases to pass through, so that the water vapor content of the front end of the water molecule separator 18 (namely, the installation area of the water vapor sensor 29) is increased, and the detection reaction speed is increased.

Example III

This embodiment differs from the second embodiment in that a guidewire lumen 27, a thermocouple 3 and a safety device 4 are provided within the cryoablation catheter 2. As shown in fig. 1 and 4, a cryoablation system with multiple safety detection and prevention devices is composed of a cryoablation device 1 and a cryoablation catheter 2, wherein the cryoablation device comprises a man-machine interaction module 11, a control module 12 and a gas circuit module 13, the man-machine interaction module 11 is electrically connected with the control module 12, the control module 12 is electrically connected with the gas circuit module 13, the cryoablation catheter 2 comprises 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 arranged in the catheter slender shaft 23, a gas inlet pipe, The refrigerating unit 24 comprises a refrigerating bag body 241 and a protecting bag body 242, the protecting bag body 242 is wrapped outside the refrigerating bag body 241, the air inlet pipe 25 and the air returning pipe 26 are in fluid communication with the inner cavity of the refrigerating bag body 241, a liquid blocking mechanism 28 is arranged in the far end of the catheter slender shaft 23, the liquid blocking mechanism 28 is arranged in a space defined by the far end inner surface of the catheter slender shaft 23 and the outer surfaces of the air inlet pipe 25, the air returning pipe 26 and the wire guide cavity tube 27, or the liquid blocking mechanism 28 is coated on the inner wall (inner surface) of the catheter slender shaft 23 and the air inlet pipe 25, the hydrophobic coating 282 on the outer surface of the muffler 26 and the guidewire lumen 27 can provide a liquid blocking effect. As shown in fig. 11 and 12, a thermocouple 3 is further disposed in the catheter slender shaft 23, the thermocouple 3 is electrically connected with the control module 12, the thermocouple 3 includes a positive electrode wire 31 and a negative electrode wire 32, the distal end 311 of the positive electrode wire 31 and the distal end 321 of the negative electrode wire 32 are both disposed in the protective capsule 242, the distal end 311 of the positive electrode wire 31 is connected with the distal end 321 of the negative electrode wire 32, the proximal ends of the positive electrode wire 31 and the negative electrode wire 32 are both electrically connected with the control module 12, and the 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, wherein the proximal end of the positive auxiliary wire 41 is electrically connected with the positive auxiliary wire 31, the distal end 411 of the positive auxiliary wire 41 is arranged in the protective capsule 242, the proximal end of the negative auxiliary wire 42 is electrically connected with the distal negative wire 32, the distal end 421 of the negative auxiliary wire 42 is arranged in the protective capsule 242, the distal end 411 of the positive auxiliary wire 41 is spaced from the distal end 421 of the negative auxiliary wire 42 by a distance, and 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.

In one embodiment, a catheter connection end 5 is disposed on the cryoablation device 1, one end of the catheter connection end 5 is fixedly connected with the air path module 13, the other end of the catheter connection end 5 is connected with the catheter handle 22 through a flexible connection pipe 21, and the air inlet pipe 25, the air return pipe 26, the positive electrode lead 31, the negative electrode lead 32, the positive electrode auxiliary lead 41 and the negative electrode auxiliary lead 42 penetrate through the lumen of the flexible connection pipe 21 and the catheter connection end 5 is connected with the cryoablation device 1.

In a preferred embodiment, the conduit connection end 5 is screwed with the gas circuit module 13.

In one embodiment, the proximal end of the air inlet tube 25 is connected to the air passage module 13, the distal end 251 of the air inlet tube 25 is disposed within the distal end of the freezing bladder 241, the proximal end of the air return tube 26 is connected to the air passage module 13, and the distal end 261 of the air return tube 26 is disposed within the proximal end of the freezing bladder 241.

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

In one embodiment, a guidewire lumen 27 is disposed within the catheter elongate shaft 23, the guidewire lumen 27 extending beyond the distal end of the catheter elongate shaft 23, the distal end of the freezing unit 24 being fixedly coupled to the guidewire lumen 27.

In operation, the cryoablation device 1 is first activated and the cryoablation catheter 2 is maneuvered into a patient. The balloon 24 is deployed within the patient after being inflated with a refrigerant. When no liquid intrusion occurs, the distal end 411 of the positive auxiliary wire 41 and the distal end 421 of the negative auxiliary wire 42 are not conductive with each other. When liquid intrusion occurs, the distal end 411 of the positive subsidiary wire 41 and the distal end 421 of the negative subsidiary wire 42 are conducted due to the conductivity of the liquid, resulting in that the electric potential measured by the thermocouple is not at the temperature measuring point at the junction of 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, but at the junction of the positive wire 31 and the positive subsidiary wire 41 and the junction of the negative wire 32 and the negative subsidiary wire 42. The potential returns to the control module 12, is processed by the control module 12 and finally is fed back to the man-machine interaction module 11, and meanwhile, the control module 12 is operated to stop the operation of the air path module 13, so that the problem of liquid invasion is further aggravated.

According to the application, the thermocouples which are normally arranged in the catheter are improved, the proximal ends of the positive auxiliary lead and the negative auxiliary lead are connected with the thermocouples, the detection of liquid is realized through the two leads by utilizing metal conductivity, and the placement of a photoelectric sensor or a liquid sensor is avoided, so that a power supply circuit is not required to be added in the catheter, the structure is simplified, the space in the lumen of the catheter is saved, the electric shock injury to a patient possibly caused under extreme conditions is avoided, the size of the catheter can be further reduced, the safety of the interventional catheter is improved, the flexibility of the catheter is increased, the catheter can adapt to different vascular conditions, and the application range is enlarged. In addition, the existing photoelectric sensor needs a power supply circuit and a signal circuit, at least four wires are needed, and the performance of the photoelectric sensor is possibly influenced by adding the four wires in a narrow space of a catheter lumen. The application reduces the number of wires required to connect with the control module at the conduit joint end, and improves the usability and stability.

Example IV

The present embodiment differs from the third embodiment in the structure of the safety device 4. As shown in fig. 13 and 14, the safety device 4 is openings 43 and 44 provided on distal end portions of the positive electrode lead 31 and the negative electrode lead 32, respectively, the openings 43 and 44 being provided on distal end sides of the liquid blocking mechanism 28, the openings 43 and 44 exposing conductive wires within the positive electrode lead 31 and the negative electrode lead 32, the conductive wires exposed by the positive electrode lead 31 and the negative electrode lead 32 not being in direct contact.

In one embodiment, a catheter connection end 5 is disposed on the cryoablation device, one end of the catheter connection end 5 is fixedly connected with the air path module 13, the other end of the catheter connection end 5 is connected with the catheter handle 22 through a flexible connection pipe 21, and the air inlet pipe 25, the air return pipe 26, the positive electrode lead 31 and the negative electrode lead 32 penetrate through the lumen of the flexible connection pipe 21 and the catheter connection end 5 is connected with the cryoablation device 1. In a preferred embodiment, the conduit connection end 5 is screwed with the gas circuit module 13.

In one embodiment, the proximal end of the air inlet pipe 25 is connected to the air passage module 13, the distal end of the air inlet pipe 25 is disposed within the distal end of the freezing bladder 241, the proximal end of the air return pipe 26 is connected to the air passage module 13, and the distal end of the air return pipe 26 is disposed within the proximal end of the freezing bladder 241.

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

In this embodiment, the positive electrode lead 31 of the thermocouple 3 and the negative electrode lead 32 of the thermocouple 3 are not attached with leads, but two openings are provided at positions spaced apart from the distal end measuring point of the thermocouple 3 in the proximal direction, and the two openings expose the conductive wires of the positive electrode lead 31 and the negative electrode lead 32 by cutting the outer skins of the positive electrode lead 31 and the negative electrode lead 32. When no liquid exists in the cavity, the exposed positive electrode conductive metal wire and the exposed negative electrode conductive metal wire are not contacted, and the potential measured by the thermocouple 3 is still the potential of the measuring point. When the liquid invades, the liquid submerges the opening, and the exposed positive electrode conductive metal wire and the exposed negative electrode conductive metal wire are conducted through the conductivity of the liquid, so that a second temperature measuring point is formed at the opening. The thermocouple potential is actually the temperature at the second temperature measurement point. The potential of the second temperature measuring point is actually different from the potential of the first temperature measuring point, and liquid invasion can be judged by the difference. The measured potential is transmitted to the control module 12, processed by the control module 12 and finally fed back to the man-machine interaction module 11, and the control module 12 is operated to stop the operation of the air path module 13, so that the problem of liquid invasion is further aggravated.

The application only uses one thermocouple to complete the liquid detection function. The internal dimension of the catheter is optimized, the safety of the interventional catheter is improved, the flexibility of the catheter is improved, and the adaptation to different vascular conditions is enlarged.

Finally, it should be understood that the foregoing description is merely illustrative of the preferred embodiments of the present application, and that no limitations are intended to the scope of the application, as defined by the appended claims.

Claims (12)

1. The cryoablation system is characterized in that the cryoablation catheter comprises a catheter slender shaft, a catheter handle arranged at the proximal end of the catheter slender shaft, a freezing unit arranged at the distal end of the catheter slender shaft, an air inlet pipe and an air return pipe arranged in a cavity of the catheter slender shaft, the air inlet pipe and the air return pipe are in fluid communication with an inner cavity of the freezing unit, a gas flow state monitoring sensor is arranged at the proximal end of the air return pipe, a liquid blocking mechanism is arranged in the distal end of the catheter slender shaft, the liquid blocking mechanism has a hydrophobic micropore structure, and the surface properties and the size structure of the liquid blocking mechanism accord with the following quantitative relation:

P<λ2cos(π-θ)/r

where P is the absolute pressure of the liquid at the leak point, lambda is the surface tension coefficient, r is Kong Dangliang hydraulic radius, and θ is the contact angle of the liquid on the pore wall.

2. The cryoablation system of claim 1 wherein a negative pressure aspiration pump is disposed proximal to the muffler and the gas flow condition monitoring sensor is disposed at an inlet of the negative pressure aspiration pump.

3. The cryoablation system of claim 1 wherein the gas flow condition monitoring sensor is a pressure sensor, a flow sensor, or a flow rate sensor, or a combination thereof.

4. The cryoablation system of claim 1 wherein the liquid blocking mechanism is a hydrophobic coating applied to the inner wall of the catheter elongate shaft and the outer walls of the air inlet tube and the air return tube or the liquid blocking mechanism is disposed within a space defined by the inner wall of the catheter elongate shaft and the outer walls of the air inlet tube and the air return tube, the liquid blocking mechanism being an array having a hydrophobic microporous structure or the liquid blocking mechanism being a hydrophobic wire disposed within a void between the inner wall of the catheter elongate shaft and the outer walls of the air inlet tube and the air return tube.

5. The cryoablation system for facilitating monitoring of fluid flow conditions of claim 4 wherein the liquid blocking mechanism is a combination of a hydrophobic coating, a hydrophobic wire, a hydrophobic microporous structure.

6. The cryoablation system of any of claims 1-5 wherein the liquid blocking mechanism has a millimeter, micron or nanometer pore structure, 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, the liquid blocking mechanism being capable of blocking liquid passage while allowing gas passage.

7. The cryoablation system of claim 6 wherein the cryounit comprises a cryoballoon and a protective balloon, the protective balloon is wrapped around the cryoballoon, the air inlet tube and the air return tube are in fluid communication with the lumen of the cryoballoon, a thermocouple is further disposed within the elongate shaft of the catheter, the thermocouple is electrically connected to the control module, the thermocouple comprises a positive wire and a negative wire, the distal end of the positive wire and the distal end of the negative wire are both disposed within the protective balloon, the distal end of the positive wire is connected to the distal end of the negative wire, and a safety device is disposed on the thermocouple.

8. The cryoablation system of claim 7 wherein the safety device is comprised of a positive satellite wire and a negative satellite wire, the proximal end of the positive satellite wire being electrically connected to the positive wire, the distal end of the positive satellite wire being disposed within the protective capsule, the proximal end of the negative satellite wire being electrically connected to the negative wire, the distal end of the negative satellite wire being disposed within the protective capsule, the distal end of the positive satellite wire not being in direct contact with the distal end of the negative satellite wire.

9. The cryoablation system of claim 7 wherein the safety device is an opening disposed on a distal portion of the positive and negative leads, respectively, the opening being disposed on a distal side of the liquid blocking mechanism, the opening exposing conductive wires within the positive and negative leads, the conductive wires exposed by the positive and negative leads not being in direct contact.

10. The cryoablation system of claim 1 wherein a water vapor sensor is disposed within the cryoablation system, the water vapor sensor in fluid communication with the catheter elongate shaft, the water vapor sensor in electrical communication with the control module.

11. The cryoablation system of claim 10 wherein a negative pressure pump is disposed within the cryoablation device, the negative pressure pump in fluid communication with the catheter elongate shaft, the negative pressure pump in electrical communication with the control module, the water vapor sensor disposed on an inlet end side of the negative pressure pump.

12. The cryoablation system of claim 11 wherein a water molecule isolator and a shut-off valve are disposed between the water vapor sensor and the negative pressure pump, the shut-off valve being electrically connected to the control module.