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EP-3592268-B1 - SYSTEMS TO ENSURE GAS EGRESS DURING CRYOTHERAPY

EP3592268B1EP 3592268 B1EP3592268 B1EP 3592268B1EP-3592268-B1

Inventors

  • MCDERMOTT, Sean A.
  • VADALA, Charles J.
  • HANLEY, BRIAN M.
  • O'CONNOR, JOHN P.

Dates

Publication Date
20260506
Application Date
20180307

Claims (6)

  1. A sensor (202, 302, 602) for use with a catheter that delivers cryogen gas within a body of a patient, comprising: a gas inlet (204, 301, 601) at a patient side of the sensor that receives cryogen gas vented from the patient's body; a gas outlet (209, 303, 603) at an atmosphere side of the sensor that vents cryogen gas out of the sensor to the atmosphere; a connection (212, 312, 612) between the sensor and a console for the catheter, and characterized by a flexure point (208, 308, 608) that deflects upon attachment of a ventilator tube to the gas outlet; and wherein the connection (212, 312, 612) comprises a switch (210, 310, 610) that is actuated upon deflection of the flexure point to convey a signal along the connection (212, 312, 612) to the console preventing the catheter from operating so that egress of cryogen gas from the gas outlet is ensured whenever the catheter is operable.
  2. The sensor of claim 1, further comprising a valve that communicates with the atmosphere at the gas outlet when the valve is open; and wherein the connection comprises a cable, the cable connected to the valve and the console, the cable controlled at the console by an actuator to open the valve automatically to the atmosphere when the catheter is operable.
  3. The sensor of claim 2, wherein the cable is a push-pull cable, and the actuator is a linear actuator.
  4. The sensor of any of the foregoing claims, wherein: the gas outlet is configured to engage with a ventilator tube; and the connection comprises an air pressure port having a first end for connection to a source of air, and a pressure relief opening on the gas outlet at a second end of the port, whereby the pressure relief opening is at least partially covered by the ventilator tube when the ventilator tube is engaged with the gas outlet, creating a threshold air pressure in the port that is measurable at the console to prevent the catheter from operating.
  5. The sensor of any of the foregoing claims, further comprising a manual vent valve that communicates with the atmosphere at the gas outlet, and wherein a valve position corresponding to the valve being open or closed is communicated via the connection to the console to allow the catheter to respectively operate or not operate.
  6. The sensor of any of the foregoing claims, wherein: the gas inlet is configured to mount to a ventilator tube inlet of an endotracheal tube adapter; the gas outlet includes a venting aperture that will not engage a ventilator tube; and the sensor includes a switch that detects when the gas inlet is mounted to the endotracheal tube adapter; and wherein the connection when the switch is actuated signals the console to allow operation of the catheter.

Description

PRIORITY This application claims the benefit of priority under 35 U.S.C. § 119 to United States Provisional Patent Application Serial No. 62/468,631, filed March 8, 2017. FIELD The present disclosure relates generally to the field of cryotherapy. In particular, the present disclosure relates to cryotherapy systems that ensure egress of gas generated as a result of cryogen liquid delivered within a patient's body during cryotherapy procedures and, more particularly, the present disclosure relates to sensors for use with cryotherapy systems that include delivery catheters, wherein the systems ensure that egress of cryogen-induced gas from the patient's body is possible whenever the catheter is operating. BACKGROUND Cryoablation, as an example of cryotherapy, is a surgical procedure in which diseased, damaged or otherwise undesirable tissue (collectively referred to herein as "target tissue" and/or "treatment region") may be destroyed by focal delivery of a cryogen spray. These systems along with other cryotherapy systems are typically referred to as cryoablation systems, cryospray systems, cryospray ablation systems, cryosurgery systems, cryosurgery spray systems and/or cryogen spray ablation systems. As typically used, "cryogen" refers to any fluid {.e.g., gas, liquefied gas or other fluid known to one of ordinary skill in the art) with a sufficiently low boiling point {i.e., below approximately - 153°C) for therapeutically effective use during a cryogenic surgical procedure. Suitable cryogens may include, for example, liquid argon, liquid nitrogen and liquid helium. Pseudo-cryogens such as liquid carbon dioxide and liquid nitrous oxide that have a boiling temperature above -153°C but still very low (e.g., -89°C for liquid N20) may also be used. For example, during operation of a cryospray ablation system, a medical professional {e.g., clinician, technician, physician, surgeon, etc.) directs a cryogen spray onto the surface of a treatment area via a cryogen delivery catheter. The medical professional may target the cryogen spray visually through a video-assisted device or endoscope, such as a bronchoscope, gastroscope, colonoscope, or ureteroscope. Cryogen spray exits the cryogen delivery catheter at a temperature ranging from 0°C to -196°C for LN2, causing the target tissue to freeze or "cryofrost." As liquid cryogen exits the cryogen delivery catheter and impacts upon the target, it converts to a gaseous state with a significant increase in volume. For example, 1 cubic centimeter (cm3) of liquid nitrogen converts to 694 cm3 of nitrogen gas at body temperature. If not properly isolated and/or vented from the patient and allowed to progress further into the body from the treatment site, these expanding gases may cause undue distention and may have life-threatening consequences, including, for example, pneumothorax of the lungs and perforations of the upper or lower gastrointestinal (GI) tract. In a cryoablation procedure in the trachea involving ventilation, an endotracheal (ET) tube with an ET tube adaptor on the proximal end of the tube may be placed in the trachea to facilitate breathing. In such conventional ventilation systems, the ventilator tube must be detached from the endotracheal tube adaptor in order for any intemal gas within the patient to egress to the open atmosphere. Accordingly, various advantages may be realized by cryotherapy systems and methods as disclosed herein, which ensure an adequate pathway for venting of cryogen gas outside of the patient whenever the cryogen delivery catheter is operable. US2004078033 discloses a cryosurgical instrument and its accessory system operating on the base of a refrigerant evaporation. US2013253491 discloses a cryosurgery system for application of medical-grade liquid nitrogen to a treatment area via a small, low pressure, open tipped catheter. The system includes a console, including a touch panel computer, a cryogen module, a suction module and an electronics module, and a disposable spray kit. US2015066005 also discloses a cryosurgery system for application of medical-grade liquid nitrogen to a treatment area via a small, low pressure, open tipped catheter. US2015306329 discloses an adapter for use in airway exchange procedure capable of being rapidly coupled and uncoupled to the catheter and being capable of regulating the flow of fluid delivered to the trachea of the patient. SUMMARY The invention is limited by the scope of independent claim 1. Further embodiments are disclosed in the dependent claims. Embodiments of the present disclosure may include a sensor for use with a catheter that delivers cryogen gas within a body of a patient. The sensor may include a gas inlet at a patient side of the sensor that receives cryogen gas vented from the patient's body. The sensor may include a gas outlet at an atmosphere side of the sensor that vents cryogen gas out of the sensor to the atmosphere. The sensor may include a connection between the sensor and