Heat exchange catheter with multi-lumen tube having a fluid return passageway

Abstract

The catheter includes a multi-lumen tube having an outflow portion and an accessory portion. The accessory portion is integrally formed within an interior volume of the outflow portion. The accessory portion has a cross-section smaller than the outflow portion. The outflow portion is offset from the accessory portion such that they are integrally joined. The space between these portions defines a fluid return passageway and the space within the accessory portion defines an accessory passageway. A flexible outer sleeve cooperates with the multi-lumen tube to form a fluid inlet passageway. During operation, an inlet flow of warming fluid flows through the fluid inlet passageway formed between the outer sleeve and the multi-lumen tube. The flow continues around a distal end of the outflow portion of the multi-lumen tube, thus becoming an outlet flow of the warming fluid which is directed through the fluid return passageway.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This is a continuation of U.S. Ser. No. 11 / 417,407, entitled “Heat Exchange Catheter with Multi-Lumen Tube Having a Fluid Return Passageway”, filed May 4, 2006 which is a continuation-in-part of U.S. Ser. No. 11 / 148,454, entitled “Heat Exchange Catheter and Method of Use”, filed Jun. 9, 2005.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to urological warming and cooling devices and more particularly to a warming catheter and method of warming the urethra of a patient during ablative surgery. The apparatus is particularly useful in cryosurgery to prevent damage to tissues surrounding a surgical site from the extremely cold temperatures employed therein. The apparatus is especially useful during transperineal cryoablation of the prostate gland in human males to maintain the temperature of the urethral tissues and thereby prevent urethral sloughing. The apparatus may also have utility where it ...

AI Technical Summary

Benefits of technology

[0016]The heat exchange catheter is particularly useful as a warming catheter for prostatic cryosurgical procedures where cryosurgical probes are used and it is desired to maintain the temperature of the urethral tissues to prevent urethral sloughing.

[0017]Utilization of a multi-lumen tube has several advantages over the '673 device discussed above. Since the inlet flow is on the outside of the heat exchange catheter heat transfer is optimized. The cost is minimized because there are fewer parts to be manufactured. Furthermore, more standard processes may be used during manufacturing.

[0018]Offset positioning of the outflow portion of the multi-lumen tube relative to the outer sleeve, in contrast to any coaxial relationship of these elements and the accessory portion of the multi-lumen tube has certain advantages. An offset relationship enhances the fluid dynamic properties of the catheter. It provides an increased turbulence, which, in turn, maximizes the heat exchange efficiency.

[0019]Furthermore, this offset positioning provides the ability to have an accessory portion of the multi-lumen tube of minimal thickness and thus enhanced flexibility, which is important, for example, for application in the urethra in which the catheter must be able to bend around the pubic bone when inserted through the urethra.

Problems solved by technology

However, other necrosed tissue may slough off and pass through the urethra, often causing undesirable blockage.

The devices would collapse if the flow were reversed.

As a result, the urethral tissue near the bladder neck sphincter (near the hot water outlet) is heated more than the urethral tissue near the external sphincter, creating a strong thermal gradient in the prostatic urethra and an uneven heating effect.

By the time the hot water reaches the external sphincter, it may have lost so much heat to the upper region of the urethra that it is not warm enough to protect the external sphincter from freezing.

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