Cryogenic System and Method of Use

Abstract

A cryogenic medical device for delivery of subcooled liquid cryogen to various configurations of cryoprobes is designed for the treatment of damaged, diseased, cancerous or other unwanted tissues. The device is a closed or semi-closed system in which the liquid cryogen is contained in both the supply and return stages. The device is capable of generating cryogen to a supercritical state and may be utilized in any rapid cooling systems. As designed, the device comprises a number of parts including a vacuum insulated outer dewar, submersible cryogen pump, baffled linear heat exchanger, multiple pressurization cartridges, a return chamber, and a series of valves to control the flow of the liquid cryogen interconnected with cryotreatment devices including cryoprobes and catheters. The cryogenic medical device promotes subcooling to the tips of various external cryogenic instrument configurations.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation of U.S. patent application Ser. No. 15 / 445,968, filed Feb. 28, 2017, which is a continuation of U.S. patent application Ser. No. 14 / 336,317, filed Jul. 21, 2014, which is a continuation of U.S. patent application Ser. No. 13 / 061,171, filed Feb. 28, 2011, which is a National Stage entry of International Patent Application Ser. No. PCT / US2009 / 62928, filed Nov. 2, 2009, and is a continuation of U.S. patent application Ser. No. 12 / 553,005, filed Sep. 2, 2009, which claims priority to U.S. Provisional Patent Application Ser. No. 61 / 093,916, filed Sep. 3, 2008; and further is a continuation of U.S. patent application Ser. No. 12 / 562,301 filed Sep. 18, 2009, which claims priority to U.S. Provisional Patent Application 61 / 098,244, filed Sep. 19, 2008, the entirety of which are herein incorporated by reference.FIELD OF THE INVENTION[0002]The present invention relates generally to the medical technology field and,...

AI Technical Summary

Benefits of technology

[0009]In one embodiment, the closed or semi-closed system has multiple pressurized cylinders filling and firing in sequence, and pressurized through a heating coil in one or more of the contained pressurized cylinders. The device is vented to the surrounding atmosphere through an adjustable pressure vent to prevent excess pressure buildup while in operation. The device comprises a number of parts including a vacuum insulated outer dewar, submersible cryogen pump, a series of self -pressurizing pulsatile delivery chambers, baffled linear heat exchanger, return chamber, and a series of valves to control the flow of the liquid cryogen. The outer dewar comprises a cryogenic apparatus having pressurizing pulsatile delivery chambers which drive liquid cryogen through the baffled linear heat exchanger. The linear heat exchanger comprises a tube-within-a-tube (i.e. chamber within a chamber configuration) whereby a vacuum is applied to the outer chamber to subcool an isolated reservoir of liquid cryogen. The inner chamber comprises a series of baffles and a central spiral to increase the flow path of the liquid cryogen while providing for increased contact-based surface area with the outer chamber to allow for more effective heat transfer and subcooling of the cryogen being delivered to the probe.

[0013]In one embodiment, a dual insulative barrier is capable of being formed. The device creates a temperature initiated transient vacuum insulation along the length of a catheter. The device further couples the temperature initiated vacuum with that of a surface modification along the inner tubes / lines to enhance nucleation and deposition of the saturated gas on the outer surface of the inner tubes to create an additional layer of insulation. The enhanced deposition or nucleation modification contributes by making the vacuum more effective. In addition, the saturated gas filled lumen of the outer tube at ambient temperature may be run at any given pressure. For exemplary purposes and not limitation, one embodiment maintains the pressure at atmospheric levels or may control the pressure to elevated or reduced levels.

Problems solved by technology

At present, current systems utilizing liquid nitrogen operate at pressures between 14-480 psi; the systems in use cannot operate or withstand pressures greater that 500 psi.

Further, the use of heat exchangers have been limited to coils placed into a bath of cryogen to allow for time consuming, inefficient passive subcooling of the cryogen in which activation of these devices circulate a cryogen (such as liquid nitrogen) to a probe to create a heat sink, thus resulting in tissue freezing.

Images