n/a
The invention relates to medical devices, and more particularly to minimally invasive surgical systems.
Medical devices configured for minimally invasive surgery are rapidly becoming the tools of choice for many surgical procedures. Not only do these devices provide an alternative to more invasive surgical tools and procedures, but they have also fostered the development of entirely new procedures.
Devices including highly flexible catheters, as well as rigid and semi-flexible probes have received increased attention in recent years and continue to be refined for cardiovascular, pulmonary, urogenital, and other applications. Devices for each of these applications present different technology and material challenges. Angioplasty catheters, for example, can require fluid-tight passages or channels for circulating a cooling fluid (liquid or gas) through a catheter to cool an electro-surgical structure, such as radio frequency ablation electrode, to prevent overheating of the electrode or of surrounding tissue. Similarly, a cooling or cryogenic fluid can be reduce the temperature of a structure, such as an ablation surface, to a therapeutic temperature. Some cooling fluids, however, can be harmful or fatal to the patient if they unintentionally escape from the surgical device.
Although careful fabrication techniques, quality materials, and thorough testing can reduce the chances of cooing fluid leakage, it would be desirable to provide additional system features that further minimize the occurrence of leaks; and should a leak occur, provide features that detect cooling fluid loss or escape immediately so that use of the surgical device can be terminated and patient remediation efforts can be undertaken if required.
The present invention provides a medical device having an elongate body defining an injection lumen and an exhaust lumen, as well as a first pliable element defining a cooling chamber disposed at a point along the elongate body, the cooling chamber in fluid communication with the injection lumen and the exhaust lumen. A second pliable element at least partially encloses the first pliable element, defining a junction between the first and second pliable element. The medical device further includes a first leak detector in fluid communication with the cooling chamber and a second leak detector in fluid communication with the junction. A check valve may be included in fluid communication with the junction, the check valve further being in fluid communication with the exhaust lumen. Moreover, a cryogenic fluid supply may be in fluid communication with the injection lumen, while a vacuum source is provided in fluid communication with the exhaust lumen. A control unit is also included in communication with the first and second leak detector, wherein the control unit is responsive to output from the first and second leak detectors to control fluid flow through the medical device.
Exemplary leak detection apparatus include an impedance measurement circuit, an infrared sensor, a pulsed ultrasonic device, or a length of duplex wire having a portion of insulation removed.
The invention will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings in which:
In the discussion which follows, “surgical device” is intended to encompass any surgical implement used in association with human or animal medical treatment, diagnosis, study, or analysis. More particularly, a surgical device is intended to encompass any implement or portion thereof that is entirely or partially inserted into a human or animal body by any means of entry, such as through a natural body orifice, an incision, or a puncture. The term surgical device is not intended to connote a limitation to treatment of a single body system, organ, or site. The surgical device can be rigid as a thick steel pipe, completely flexible and pliant like a thread, or have a flexibility between the two extremes. The surgical device can have a diameter that ranges from inches to microns.
As used herein, “fluid” is intended to encompass materials in a liquid state, a gas state, or in a transition state between liquid and gas, and liquid and solid. The fluid can be a “cryogenic fluid” capable of reaching or creating extremely cold temperatures well below the freezing point of water, such as below minus 20 degrees Centigrade; a “cooling fluid” that does not reach or create temperatures below the freezing point of water; a fluid capable of transferring heat away from a relatively warmer structure or body tissue; a fluid capable of transferring heat to a relatively cooler structure or body tissue; a fluid at or capable of creating a temperature between the freezing and boiling points of water; and a fluid at or capable of reaching or creating a temperature above the boiling point of water.
A “fluid path” as used herein is intended to encompass any boundary, channel or guide through which a fluid can travel. It can include concentrically disposed catheters, multi-lumen catheters, or a single loop of tubing within a sheath. The fluid path can also include connectors and valves, as well as passages in support equipment, such as the console disclosed herein.
Referring now to
Either or both of the catheter 12 and the console 10 can be provided with detection devices that are in electrical communication with the console and which provide a signal output that can be representative of an event that indicates flow path integrity loss or a leak within a sealed catheter and/or console. As shown in
The purpose and function of the leak detectors is better understood once another feature of the invention is introduced, namely, a vacuum pump 24, as shown in
Although a single type of leak detector could be functional, an exemplary embodiment of the invention is provided with three different types of leak detectors for enhanced detection probability. For example, the first leak detector 18 can be a simple circuit formed by a wire, such as a pull-wire used to help steer the catheter tip, and a conductive catheter tip portion. Specifically, as shown in
However, some catheters 12 may include multiple conductors running within one or more lumens and electrical insulation on the conductors is necessary to avoid unwanted electrical connections and interferences. Many such catheters also contain uninsulated wires, for example as mechanical deflectors to alter catheter configuration, or for example as stiffening agents to alter catheter flexibility or pushability. However, if the pull wire (or other wire that is part of the leak detection circiut) contacts another uninsulated wire, electrode ring or other conductive element, a false leak detection signal could be generated. Accordingly, a form of insulation that provides mechanical insulation while allowing fluid conductivity is desirable.
Although the first leak detector 18 is well suited for detecting leaks at or near the distal end of the catheter 12, a leak may develop between the distal end and the handle portion 21 of the catheter and an infrared sensor can be disposed in the handle as the second leak detector 20. As soon as the first and/or second leak detectors output a signal to the console indicative of a leak, the refrigerant injection can be stopped. In an exemplary embodiment, shown in
Even though refrigerant injection is stopped, it can still be desirable to apply vacuum to the catheter to withdraw refrigerant already introduced into the catheter, along with refrigerant contaminated blood. Thus, a third leak detector 22 (shown in
In an alternative embodiment, leak detection may be provided for a catheter having one or more expandable elements, e.g., a balloon catheter or the like.
The catheter 12 further provides a second pliable element 62 at least partially enclosing the first pliable element 58, thereby defining a junction 64 between the first and second pliable elements. The second pliable element 62 provides a safeguard to prevent fluid from leaking out of the cooling chamber 60 and into surrounding tissue should the first pliable element 58, and therefore the cooling chamber 60, rupture or develop a leak. The junction 64 between the first and second pliable elements may be substantially under a vacuum, such that the first and second pliable elements are generally in contact with each other, with little or no open space between them.
A check valve 66 is provided in fluid communication with the junction 64 between the first and second pliable elements, with the check valve 66 also being in fluid communication with the exhaust lumen 54. The check valve 66 is a one way valve that prevents fluid from traveling from the exhaust lumen 54 into the junction 64 between the first and second pliable elements, yet allows fluid, if any, to flow from the junction 64 between the first and second pliable elements towards the exhaust lumen 54. The check valve 66 may be such that the valve opens automatically in response to a pressure change in the junction 64.
A first leak detector 68 may be included in fluid communication with the junction 64 to provide the ability to detect any ingress of blood or fluid into the junction 64, thereby indicating a leak or other structural compromise of the catheter. Further, a second leak detector 70 may be included in fluid communication with the exhaust lumen 54, which could indicate when a leak in the guidewire lumen or other structural breach has allowed fluid ingress into the exhaust lumen 54. Although the first and second leak detectors are described as independent, they may be in communication with each other at some point along the length of the catheter, i.e., the second leak detector 70 may be an extension or branch of the first leak detector 68. The first and second leak detectors can detect an ingress of fluid by providing an impedance measurement, which would change upon the presence of blood or other foreign fluids within the junction 64 or exhaust lumen 54. Alternatively, the leak detectors may include an insulated length of duplex wire 72, where a portion of the wire insulation has been stripped as shown in
In an exemplary operation of the embodiment described above, fluid flow is provided through the first fluid path. At least partially surrounding the first pliable element 58 is the second pliable element 62, with the junction 64 formed therebetween substantially under a vacuum. As the check valve 66 is provided in fluid communication with both the junction 64 between the first and second pliable element as well as the exhaust lumen 54, the fluid pressure in the exhaust lumen 54 is higher than that of the vacuum pressure in the junction 64. As a result, the check valve 66 remains closed under normal operating conditions, preventing any fluid flow through the check valve 66.
However, in the event of a leak or rupture of either the first pliable element 58 or the second pliable element 62, fluid will flow into the junction 64 between the two pliable elements, thus eliminating the vacuum in the junction 64. As a result, if the pressure in the junction 64 exceeds that of the pressure in the exhaust lumen 54 downstream of the check valve 66, then the check valve 66 will open. Subsequently, as the check valve 66 is forced open due to the pressure change, a second fluid path results, which flows from the cooling chamber 60 into the junction 64 between the first and second pliable element 62, through the check valve 66, and into the exhaust lumen 54.
It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings without departing from the scope and spirit of the invention, which is limited only by the following claims.
This application is a continuation-in-part of and claims priority to pending application Ser. No. 10/889,620, filed Jul. 12, 2004, by Marwan Abboud, et al., entitled LEAK DETECTION SYSTEM, which application is continuation of application Ser. No. 10/124,560, filed Apr. 17, 2002, by Marwan Abboud, et al, entitled LEAK DETECTION SYSTEM, now issued U.S. Pat. No. 6,761,714, which application is a divisional of and claims priority from U.S. patent application Ser. No. 09/489,707, filed Jan. 24, 2000, by Marwan Abboud, et al, entitled LEAK DETECTION SYSTEM, now issued U.S. Pat. No. 6,569,158, which application is related to and claims priority from U.S. Provisional Patent Application Ser. No. 60/117,175, filed Jan. 25, 1999, by Marwan Abboud, et al., entitled CRYOABLATION SYSTEM, now expired, the entirety of all of which are incorporated herein by reference.
Number | Date | Country | |
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60117175 | Jan 1999 | US |
Number | Date | Country | |
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Parent | 09489707 | Jan 2000 | US |
Child | 10124560 | Apr 2002 | US |
Number | Date | Country | |
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Parent | 10124560 | Apr 2002 | US |
Child | 10889620 | Jul 2004 | US |
Number | Date | Country | |
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Parent | 10889620 | Jul 2004 | US |
Child | 11129021 | May 2005 | US |