SELF-CENTERING PATIENT TEMPERATURE CONTROL CATHETER
A catheter includes working fluid supply and return lumens through which working fluid circulates to exchange heat with a patient in whom the catheter is positioned. Plural wires arranged in a mesh are located longitudinally along the catheter and engaged therewith. The mesh can be moved between a radially expanded configuration, in which the mesh circumscribes an inner wall of a vessel in which the catheter is disposed and in which blood flowing through the vessel is not significantly impeded from flowing within the mesh past the catheter, and a radially collapsed configuration, in which the mesh lies against the catheter or is closely spaced therefrom to facilitate advancement and retraction of the catheter from the vessel.
The present application relates generally to patient temperature control systems.
BACKGROUND OF THE INVENTIONIt has been discovered that the medical outcome for a patient suffering from severe brain trauma or from ischemia caused by stroke or heart attack or cardiac arrest is improved if the patient is cooled below normal body temperature (37° C.). Furthermore, it is also accepted that for such patients, it is important to prevent hyperthermia (fever) even if it is decided not to induce hypothermia. Moreover, in certain applications such as post-CABG surgery, it might be desirable to rewarm a hypothermic patient.
As recognized by the present application, the above-mentioned advantages in regulating temperature can be realized by cooling or heating the patient's entire body using a closed loop heat exchange catheter placed in the patient's venous system and circulating a working fluid such as saline through the catheter, heating or cooling the working fluid as appropriate in an external heat exchanger that is connected to the catheter. The following U.S. patents, all of which are incorporated herein by reference, disclose various intravascular catheters/systems/methods for such purposes: U.S. Pat. Nos. 6,881,551 and 6,585,692 (tri-lobe catheter), U.S. Pat. Nos. 6,551,349 and 6,554,797 (metal catheter with bellows), U.S. Pat. Nos. 6,749,625 and 6,796,995 (catheters with non-straight non-helical heat exchange elements), U.S. Pat. Nos. 6,126,684, 6,299,599, 6,368,304, and 6,338,727 (catheters with multiple heat exchange balloons), U.S. Pat. Nos. 6,146,411, 6,019,783, 6,581,403, 7,287,398, and 5,837,003 (heat exchange systems for catheter), U.S. Pat. No. 7,857,781 (various heat exchange catheters).
SUMMARY OF THE INVENTIONAccordingly, a catheter includes at least one working fluid supply lumen and at least one working fluid return lumen. Working fluid circulates through the supply and return lumens to exchange heat with a patient in whom the catheter is positioned. At least one of the lumens is defined by plural coils axially spaced from each other. Furthermore, at least a first coil is a large coil that inflates with working fluid to seat against a wall of a blood vessel in which the catheter is positioned such that blood may flow through the coil so as not to block blood flow in the vessel. Thus, working fluid may flow serially through the coils to exchange heat with the patient.
In some embodiments, a second of the plural coils may be a smaller coil relative to the large coil, where the smaller coil does not contact the wall of the blood vessel when inflated with working fluid. Even further, if desired, at least one of the lumens may define plural large coils separated from each other by at least one small coil as described herein. Also if desired, at least one of the lumens may define a straight tube coaxial with the coils and in fluid communication with the coils. In non-limiting embodiments, the straight tube may extend through the coils, or may optionally be located outside the coils.
In some non-limiting embodiments, the coils may be in the working fluid supply path and the straight tube may define at least part of the working fluid return path. In other non-limiting embodiments, the coils may be in the working fluid return path and the straight tube may define at least part of the working fluid supply path.
In still another aspect, a catheter includes working fluid supply and return lumens. Working fluid circulates through the supply and return lumens to exchange heat with a patient in whom the catheter is positioned. The catheter also includes at least one expandable wire located longitudinally along the catheter and engaged with the catheter. The wire is expandable against a wall of a blood vessel in which the catheter is positioned to center heat exchange regions of the catheter in the vessel. In one example, the at least one wire includes plural wires arranged in a mesh movable between a radially expanded configuration, in which the mesh circumscribes an inner wall of a vessel in which the catheter is disposed and in which blood flowing through the vessel is not significantly impeded from flowing within the mesh past the catheter, and a radially collapsed configuration, in which the mesh lies against the catheter or is closely spaced therefrom to facilitate advancement and retraction of the catheter from the vessel.
The details of the present invention, both as to its structure and operation, can best be understood in reference to the accompanying drawings, in which like reference numerals refer to like parts, and in which:
Referring initially to
As shown, working fluid may be circulated between the heat exchange system 12 and catheter 10 through supply and return lines 16, 18 that connect to the proximal end of the catheter 10 as shown. A patient temperature signal from a catheter-borne temperature sensor on the distal region of the catheter may be provided to the system 12 through an electrical line 20, or wirelessly if desired. Alternatively, a patient temperature signal may be provided to the system 12 from a separate esophageal probe or rectal probe or tympanic sensor or bladder probe or other temperature probe that measures the temperature of the patient 14. Note that as used herein, “proximal” and “distal” in reference to the catheter are relative to the system 12.
The catheter 10, in addition to ulterior supply and return lumens through which the working fluid is circulated, may also have one or more infusion lumens connectable to an IV component 22 such as a syringe or IV bag for infusing medicaments into the patient, or an instrument such as an oxygen or pressure monitor for monitoring patient parameters, etc.
The catheter 10 can be positioned typically in the vasculature of the patient 14 and more preferably in the venous system of the patient 14 such as in the inferior vena cava through a groin insertion point or the superior vena cava through a neck (jugular or subclavian) insertion point.
Next, regarding
Furthermore, it is to be understood that distal heat exchange regions of the catheters as described herein may be made of a shape memory material such as, but not limited to, nitinol in non-limiting embodiments. Also in non-limiting embodiments, the shape memory material disclosed herein may expand and contract in accordance with present principles. However, it is to be further understood that the heat exchange regions as disclosed herein may be flexible and/or pliant in non-limiting embodiments such that distal regions of the catheters of
Now specifically in reference to
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However, it may be appreciated from the non-limiting embodiment of
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Thus, as shown in
As understood herein, the wire(s) 58 may be made of a shape memory substance such as, but not limited to, nitinol. It is to be further understood that the heat exchange regions) 60 may be substantially coaxial with the wire(s) 58 when the wire(s) 58 is expanded against the wall of the blood vessel, which may be further appreciated in
Thus,
It may be appreciated from
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Thus, as shown in
As understood herein, the wires 78 may be made of a shape memory substance in accordance with present principles. It is to be further understood that the heat exchange region(s) 80 may be substantially coaxial with the wires 78 when the wires 78 are expanded against the wall of the blood vessel, which may be further appreciated in reference to
In contrast to the embodiment described in reference to
Accordingly, the catheter 68 as shown in
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To this end, a distal end portion 120 of the mesh 116 is fixedly secured to the distal end of the catheter 100 as shown. This securing may be effected by, without limitation, solvent bonding, rf sealing, ultrasonic welding, etc. If desired, a marker band 122 may be disposed along the distal portion of the catheter to visualize positioning of the catheter using, e.g., fluoroscopy.
On the other hand, a proximal end portion 124 of the mesh 116 is fixedly secured to an axially movable sheath 126 that may surround the body of the catheter 100, terminating proximally at an operator 128. The operator 128 may be moved proximally by a person to pull the proximal portion 124 of the mesh 116 away from the distal portion 120, moving the mesh 116 toward the radially collapsed configuration of
While the particular SELF-CENTERING PATIENT TEMPERATURE CONTROL CATHETER is herein shown and described in detail, it is to be understood that the subject matter which is encompassed by the present invention is limited only by the claims.
Claims
1. A catheter, comprising;
- working fluid supply and return lumens through which working fluid circulates to exchange heat with a patient in whom the catheter is positioned; and
- at least one expandable wire located longitudinally along the catheter and engaged therewith, the wire being expandable against a wall of a blood vessel in which the catheter is positioned to center heat exchange regions of the catheter in the vessel.
2. The catheter of claim 1, wherein the wire is made of a shape memory substance.
3. The catheter of claim 1, wherein the heat exchange regions are substantially coaxial with the wire when the wire is expanded against the wall of the blood vessel.
4. The catheter of claim 1, wherein the catheter is engaged with plural wires alternating longitudinally along the catheter such that only one wire is engaged with only-one longitudinal portion of the catheter.
5. The catheter of claim 1, wherein the catheter is engaged with plural wires located along the same longitudinal portion of the catheter.
6. The catheter of claim 1, wherein the at least one wire includes plural wires arranged in a mesh movable between a radially expanded configuration, in which the mesh circumscribes an inner wall of a vessel in which the catheter is disposed and in which blood flowing through the vessel is not significantly impeded from flowing within the mesh past the catheter, and a radially collapsed configuration, in which the mesh lies against the catheter or is closely spaced therefrom to facilitate advancement and retraction of the catheter from the vessel.
7. A catheter, comprising:
- working fluid supply and return lumens through which working fluid circulates to exchange heat with a patient in whom the catheter is positioned; and
- plural wires arranged in a mesh located longitudinally along the catheter and engaged therewith, the mesh being movable between a radially expanded configuration, in which the mesh circumscribes an inner wall of a vessel in which the catheter is disposed and in which blood flowing through the vessel is not significantly impeded from flowing within the mesh past the catheter, and a radially collapsed configuration, in which the mesh lies against the catheter or is closely spaced therefrom to facilitate advancement and retraction of the catheter from the vessel.
8. The catheter of claim 7, wherein the wire is made of a shape memory substance.
Type: Application
Filed: Mar 13, 2015
Publication Date: Jul 2, 2015
Inventors: Jeremy T. Dabrowiak (Redwood City, CA), Alex L. Lim (Santa Clara, CA), Venkata Vishnu Gurukula (Mountain View, CA), Richard A. Helkowski (Redwood City, CA), Masoumeh Mafi (Mountain View, CA)
Application Number: 14/656,915