Catheter with multiple heating/cooling fibers employing fiber spreading features

Abstract

A catheter using multiple hollow fibers to carry a heating / cooling fluid employs fiber spreading features to improve heat transfer and help prevent clotting of body fluids within which the catheter is immersed. The catheter includes a length of outer tube surrounding an inner tube. The inner tube conveys fluids in one direction, and the passageway between inner and outer tubes conveys fluids in the opposite direction. The inner and outer tubes have proximal distal ends. The distal end is closed, but the proximal end is open to permit introduction of a heating or cooling fluid into the inner tube, and withdrawal of the fluid from the passageway between the inner and outer tubes. At the tubes' distal end resides a proximal fluid transfer housing coupled to multiple hollow heat exchange fibers. The distal ends of these fibers may be commonly connected to a distal fluid transfer housing and optional reservoir, which cooperatively return fluid to the passageway between inner and outer tubes. In another embodiment, each fiber includes both outflowing and return lumens, enabling the fibers' distal ends to freely move about. In another embodiment, each fiber proceeds outward from the proximal fluid transfer housing, and returns back to form a loop. In each different embodiment, the invention includes one or more actuating structures to spread the fibers. The actuating structure may include, for example, fiber shaping, a retractable spreading member, elastic bias built into the fibers, etc.

Description

[0001] This application is a continuation-in-part of U.S. application Ser. No. 09 / 133,813, entitled "Indwelling Heat Exchange Catheter and Method of Using Same," filed on Aug. 13, 1998. The foregoing application will be referred to as the parent '813 application.[0002] 1. Field of the Invention[0003] The present invention relates to catheters that effect heat exchange using a bundle of multiple hollow fibers.[0004] 2. Description of the Related Art[0005] In warm blooded creatures, temperature regulation is one of the most important functions of the body. Despite the known importance of properly maintaining body temperature, scientists have discovered certain beneficial effects of artificially inducing a hypothermic state. For instance, cooling the body can help regulate vital functions during surgery by lowering the metabolism. With stroke, trauma, and other pathological conditions, hypothermia also reduces the permeability of the blood / brain barrier. Also, induced hypothermia inhib...

AI Technical Summary

Benefits of technology

[0013] A different embodiment is called "free tip" because the fibers are not bound at the catheter's tip. This embodiment eliminates the distal fluid transfer housing and reservoir. Here, each hollow fiber incorporates an outflowing lumen and a return lumen. In this embodiment, the proximal fluid transfer housing not only directs fluid into the outflowing lumens, but also guides fluid from the return lumens into the passageway between the inner and outer tubes.

[0017] The invention affords its users with a number of distinct advantages. Chiefly, by spreading the heating / cooling fibers the invention helps prevent clotting of blood or other body fluids that surround the catheter. In addition, with more widely distributed fibers, the catheter of this invention can cool the nearby tissue more efficiently. The invention also provides a number of other advantages and benefits, which should be apparent from the following description of the invention.

Problems solved by technology

Although this technique has been used with some success, some physicians may find it cumbersome, and particularly time consuming.

Also, it is difficult to precisely control body temperature with ice packing.

As a result, the patient's body temperature overshoots and undershoots the optimal temperature, requiring physicians to add or remove ice.

Furthermore, there is some danger of injuring the skin, which is necessarily cooled more than any other body part.

Nonetheless, some delay is still inherent, first for a cooling element to change the temperature of the cooling medium, and then for the temperature adjusted cooling medium to cool the desired body part.

This delay is even longer if the targeted body part is an internal organ, since the most effective cooling is only applied to the skin, and takes some time to successively cool deeper and deeper layers within the body.

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