Abstract
A catheter system for controlling the body temperature of a patient by modifying the temperature of blood flowing within a blood vessel of the patient. The catheter system comprises a catheter body having a heat exchange region in contact with the blood; and a temperature probe having a distal end that extends from the catheter body, thereby monitoring the temperature of blood flowing within the blood vessel.
Claims
1.-59. (canceled)
60. A heat exchange catheter system comprising: a heat exchange catheter device comprising a catheter shaft and a temperature probe lumen which extends between a proximal opening on the heat exchange catheter device and a distal opening on the catheter device; and, an elongate temperature probe having a proximal portion and a distal end; the temperature probe being insertable into the temperature probe lumen and, when so inserted, axially advanceable from a non-deployed position in which the distal end resides within the temperature probe lumen and the proximal portion extends out of the proximal opening; to a deployed position in which some of the proximal portion has been advanced through the proximal opening and into the temperature probe lumen and the distal end has advanced out of the distal opening to a position a spaced distance away from the heat exchange catheter device.
61. A system according to claim 60 wherein said spaced distance is a distance sufficient to allow the temperature probe to accurately sense the body temperature of a subject in whom the heat exchange catheter device has been inserted.
62. A system according to claim 60 wherein said spaced distance is between 1.8 mm and 3.2 mm from the heat exchange catheter device.
63. A system according to claim 62 wherein the temperature probe further comprises indicia which indicates when the distal end of the temperature probe has reached said spaced distance.
64. A system according to claim 63 wherein said indicia comprises marking on the proximal portion of the temperature probe.
65. A system according to claim 64 wherein the heat exchange catheter device has a proximal hub and wherein the proximal opening comprises a port on the proximal hub.
66. A system according to claim 65 wherein distally advancing the proximal portion of the temperature probe until the marking becomes aligned with the port indicates that the distal end of the temperature probe has reached said spaced distance.
67. A system according to claim 60 further comprising a locking surface for locking the temperature probe in its current axial position within the temperature probe lumen.
68. A system according to claim 67 wherein the locking surface is useable to lock the temperature probe in position after its distal end has been advanced to said spaced distance.
69. A system according to claim 60 wherein the heat exchange catheter comprises a closed loop catheter through which a heat exchange fluid is circulated.
70. A system according to claim 60 wherein the temperature probe has at least one thermistor at or near its distal end.
71. A system according to claim 70 wherein said at least one thermistor comprises first and second thermistors.
72. A system according to claim 1 wherein the temperature probe comprises an elongate member having at least one temperature sensor at or near the distal end and one or more wires for connecting said at least one temperature sensor to an extracorporeal control device.
73. A system according to claim 72 further comprising a control device programmed to use signals received from said at least one temperature sensor to control operation of the heat exchange catheter.
74. A system according to claim 60 wherein at least a portion of the temperature probe lumen is within the catheter shaft.
75. A system according to claim 60 wherein at least a portion of the temperature probe lumen is external to the catheter shaft.
76. A system according to claim 60 wherein the temperature probe lumen extends external of and along at least a portion of the catheter shaft.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0050] FIG. 1 is a perspective view of a catheter system in accordance with the present invention;
[0051] FIG. 2A is a sectional view of the catheter illustrated in FIG. 1 taken along the line 2A-2A;
[0052] FIG. 2B is a sectional view of the catheter illustrated in FIG. 1 taken along the line 2B-2B;
[0053] FIG. 2C is a cross section of the balloon portion of the catheter taken along the lines 2C-2C in FIG. 1;
[0054] FIG. 3A is a sectional view of the catheter illustrated in FIG. 1 of the portion of the catheter of FIG. 1 contained in circle 3A-3A;
[0055] FIG. 3B is an elevation view of a distal end portion of a temperature probe lumen in accordance with the present invention;
[0056] FIG. 4 is an elevation view of a distal end portion of a temperature probe lumen in accordance with an alternative embodiment of the present invention; and
[0057] FIG. 5 is an elevation view of a distal end portion of a temperature probe lumen in accordance with an alternative embodiment of the present invention; and
[0058] FIG. 6 is an elevation view of a distal end portion of a temperature probe lumen in accordance with an alternative embodiment of the present invention.
[0059] FIG. 7 is an elevational view of the cable and connector of the invention;
[0060] FIG. 8A is an elevational view of a distal end portion of a catheter system of an alternative embodiment of the present invention with the probe shown in a deployed state;
[0061] FIG. 8B is an elevation view of a distal end portion of a temperature probe in accordance with an alternative embodiment of the present invention with the probe shown in a collapsed state;
[0062] FIG. 9A is an elevation view of a distal end portion of a temperature probe in accordance with an alternative embodiment of the present invention with the probe shown in an undeployed state;
[0063] FIG. 9B is an elevation view of a distal end portion of a temperature probe in accordance with an alternative embodiment of the present invention with the probe shown in a deployed state;
[0064] FIG. 10A is an elevation view of a distal end portion of a temperature probe in accordance with an alternative embodiment of the present invention with the probe shown in an undeployed state;
[0065] FIG. 10B is an elevation view of a distal end portion of a temperature probe in accordance with an alternative embodiment of the present invention with the probe shown in a deployed state;
[0066] FIG. 11A is an elevation view of a distal portion of a temperature probe in accordance with an alternative embodiment of the present invention with the probe shown in an undeployed state;
[0067] FIG. 11B is an elevation view of a distal portion of a temperature probe in accordance with an alternative embodiment of the present invention with the probe shown in a deployed state;
[0068] FIG. 12A is an elevation view of a distal end portion of a temperature probe in accordance with an alternative embodiment of the present invention with the probe shown in an undeployed state;
[0069] FIG. 12B is an elevation view of a distal end portion of a temperature probe in accordance with an alternative embodiment of the present invention with the probe shown in a deployed state;
[0070] FIG. 13A is an elevation view of a distal end portion of a temperature probe in accordance with an alternative embodiment of the present invention with the probe shown in an undeployed state;
[0071] FIG. 13B is an elevation view of a distal end portion of a temperature probe in accordance with an alternative embodiment of the present invention with the probe shown in a deployed state;
[0072] FIG. 14 is a cross section of the catheter system of the invention taken along the line 14-14 in FIG. 13B;
[0073] FIG. 15A is an elevation view of a distal end portion of a catheter system of the present invention;
[0074] FIG. 15B is an elevation view of a distal end portion of a catheter system in accordance with an alternative embodiment of the present invention;
[0075] FIG. 16A is an elevation view of a distal end portion of a temperature probe in accordance with an alternative embodiment of the present invention with the probe shown in an unadvanced state;
[0076] FIG. 16B is an elevation view of a distal end portion of a temperature probe in accordance with an alternative embodiment of the present invention with the probe shown in an advanced state;
[0077] FIG. 17A is an elevation view of a distal end portion of a temperature probe in accordance with an alternative embodiment of the present invention with the probe shown in an undeployed state;
[0078] FIG. 17B is an elevation view of a distal end portion of a temperature probe in accordance with an alternative embodiment of the present invention with the probe shown in a deployed state;
[0079] FIG. 18A is an elevational view of the proximal end of a catheter system of FIG. 17A where the with the distal end of the probe is undeployed; and
[0080] FIG. 18B is an elevational view of the proximal end of a catheter system of FIG. 17B with the distal end of the probe deployed.
DESCRIPTION OF SPECIFIC EXEMPLARY EMBODIMENTS
[0081] Referring to FIG. 1, a heat exchange catheter system that includes a catheter body 10 is illustrated. Catheter body 10 may comprise any type of heat exchange catheter. Numerous suitable examples of heat exchange catheter systems which may comprise the present catheter body 10 are found in various US Patents. It is to be understood that the present invention may be adapted for use with a wide variety of different temperature regulating catheter systems. For example, in accordance with the present invention, the catheter system used may comprise a catheter system adapted for warming the body fluid passing thereover (for example, a system having an electric heater disposed therein, or a catheter with a heat exchange region thereon which is warmed by circulating warm heat exchange fluid therethrough). In addition, the catheter system used may comprise a catheter system adapted for cooling the body fluid passing thereover (for example, a catheter with a heat exchange region such as a heat exchange balloon or the like thereon, which heat exchange region is placed in the blood stream and cooled by pumping a cooled fluid flow therethrough). Furthermore, those skilled in the art will understand that even non-heat exchange catheters may be used with the present invention if a catheter having an on-board deployable temperature probe is desirable.
[0082] In the embodiment of the invention illustrated in FIG. 1, catheter body or shaft 10 includes a proximal end portion 11 in the form of a Y adaptor, a heat exchange region 16 on the distal portion of the catheter in the form of a helically wound multi-lobed balloon, a temperature probe exit region 17 as illustrated in FIG. 3A, and a distal end 19 having a soft, atraumatic tip 25.
[0083] The heat exchange region 16 is heated or cooled by the flow of a heat exchange liquid therethrough. Referring to FIG. 2A, the shaft 10 has four lumens therein proximal of the temperature probe exit region 17, and three lumens therein distal of that region. Proximal of that region, the shaft includes an inflow lumen 12, an outflow lumen 13, a guidewire lumen 14 and a temperature probe lumen 15. The transition between the four lumen (FIG. 2A) and three lumen (FIG. 2B) catheter tubing may be made by merely skiving off the top portion of the tube, or may be a joinder of the three lumen extrusion to four lumen extrusion using extension tubes between the three lumens to be retained and an external jacket around that joined length of catheter shaft made of the two different extrusions. The jacket may be heat shrunk or heat welded around the tubing to secure the joint. Outflow lumen 13 is fluidly connected between outflow connector 84 and outflow lumens 58, 60, 62. Inflow lumen is fluidly connected between inflow connector 82 and balloon inflow lumen 64. A complete description of heat transfer catheters similar to that described here is included in U.S. Pat. No. 6,231,594 B1 owned by applicant's assignee and incorporated herein in full, and U.S. application Ser. No. 09/777,612.
[0084] The proximal end of the catheter of the invention terminates in a Y adaptor 78 which is attached to an outflow connector 84, an inflow connector 82, a guide wire lumen terminus 83, a temperature probe lumen terminus 86, and an aspiration valve 88. A short length of strain relief tubing 90 may be placed over the catheter at the location where it attaches to the Y adaptor. The outflow connector may fluidly connect the outflow lumen 13 to an outflow line 92 carrying heat exchange fluid between the outflow lumen and the controller 25. The inflow connector fluidly connects the inflow lumen of the catheter 12 to an inflow line 94 that carries heat exchange fluid from the controller to the inflow lumen. The inflow connector 84 may be closed, and the heat exchange fluid in the balloon withdrawn through the aspiration valve 88 when it is desired to collapse the balloon, for example when the catheter is to be withdrawn from within the vasculature of a patient. The guide wire lumen terminus provides access from the Y adaptor to the guide wire lumen 14 that extends entirely through the catheter for insertion of a guide wire 27 therethrough. The guidewire lumen also functions as a working lumen for the injection of drugs, thrombolytics, or other substances from outside the body to a location distal to the catheter, or for sensing the pressure of the blood stream distal of the catheter. It is also possible to insert other devices through the lumen, for example a temperature sensor for sensing the temperature distal of the heat exchange balloon, an angioplasty catheter for treating the patient at a location distal of the balloon, an angiojet type device or any similar type device for treatment distal of the balloon. In fact, it is possible if a temperature is sensed proximal of the balloon, and another temperature is sensed distal of the balloon, and the amount of energy emitted or absorbed by the balloon is determined, to determine blood flow.
[0085] The proximal portion of the temperature probe 20 exits the catheter from the temperature probe lumen terminus 86. The proximal end terminates in an appropriate plug, for example a plastic clip type plug 96. That plug, in turn attaches to a clip type jack 98 reminiscent of the type of plastic clip attachments common in telephones and similar devices. This plug to jack attachment connects the temperature probe electrically to the temperature probe cable 100 which in turn is connected to the controller. This provides for temperature signals generated by the temperature probe as will be described below to be transmitted to the controller so that the controller may control the heating and cooling effected by the catheter based on temperature feed back from the patient as described in U.S. Pat. Nos. 6,149,673 and 6,149,676 incorporated herein in full. A controller suitable for receiving temperature signals generated by the present invention and using said signals to control the transfer of heat from a patient is described in U.S. patent application Ser. No. 09/707,257 incorporated herein in full.
[0086] A temperature probe 20 is included and is movable within temperature probe lumen 15. As can be seen in FIGS. 3b, 4, 5 and 6, the temperature probe preferably includes temperature sensor such as a thermistor 21 at its distal end portion 22. Other temperature sensors may be employed, for example a thermocouple, light probes capable of sensing temperature, infra red sensors, or similar device, as long as the sensor is able to sense the temperature of a specified tissue and generate a signal representing that temperature that may subsequently be transmitted to a controller for controlling the heat exchange of a heat exchange catheter or for some other desired purpose. In the example as shown in this embodiment, the temperature sensor is a thermistor, the sensed is that of the blood surrounding the thermistor, and the signal generated is an electrical signal representing that temperature.
[0087] At least a portion 23 of the temperature probe adjacent its distal end portion generally comprises insulating materials. A coating of plastic 106, as in encasing the signal wires 102, 104 within a plastic tube, may be sufficient. It is important that the wires that carry the electric signal from the thermistor be sufficiently insulated that they do not conduct the temperature of the heat exchange catheter to the thermistor and thereby significantly influence the temperature sensed by the thermistor.
[0088] For safety reasons, it is generally preferable that there be redundancy in the temperature sensors. For example, the distal portion of the temperature probe may contain two thermistors each of which has independent connector wires that extend down the probe to the connection 96/98 and thus to the controller. The controller is generally programmed so that if the two signals do not correspond to each other within some predetermined range, the controller responds appropriately. For example, it may sound an alarm; it may flash a warning on a user interface if it has one; it may cease to provide hot or cold heat exchange fluid to the catheter, or any combination including all of the above. While this redundancy will generally not be repeated as to each embodiment described below, it is to be understood that such redundancy may be a feature incorporated into each embodiment. Furthermore, the redundancy may be accomplished by incorporating two or more sensors in each probe, or by incorporating more than one embodiment of the probe in a particular catheter.
[0089] FIGS. 2A, 2B illustrate cross sections of the catheter depicting the portion of the catheter shaft containing the temperature probe lumen. The innerdiameter of temperature probe lumen 15 is generally in a range of 0.020 to 0.035-0. Preferably, the inner-diameter of the temperature probe lumen is about 0.030 and may not be round, depending on the extrusion. The temperature probe along its length is configured to move through the lumen, for example, the probe may comprise a tube with thermistors in it near the distal end and wires for transmitting a signal from the thermistors contained within the tube. The tube may have, for example an outer diameter of about 0.025 or less. As described below, the diameter of the probe along its length may vary. For example, a portion may be flat for alignment with a flat exit ramp; a portion may have a slightly larger diameter so that it cannot be entirely withdrawn, or the like. If the probe is of the type that is moved within the temperature probe lumen, the probe, the lumen, or both may be constructed of material that slides easily against the other such as PTFE (Teflon) or FEP.
[0090] FIG. 4 illustrates a slot 30 at the distal end portion of the temperature control lumen. The slot is provided to allow thermistor 21 of temperature probe 20 to protrude from the catheter in order that the thermistor may be advanced away from the catheter shaft and into the blood stream when the catheter is inserted into a subject's blood vessel. As can be seen in FIG. 4, the thermistor preferably curls into a substantially J-shape so that it moves away from the catheter and the effects of the temperature generated by the heat exchange catheter, thus allowing the thermistor to obtain a more accurate measurement of the temperature of blood flow of the subject. Preferably, the tip of the temperature probe containing the thermistor moves at least 1.8-2.2 mm away from the catheter. The temperature control catheter generally contains a flow of heat exchange fluid at a temperature different than the blood temperature of the patient, and it has been found that if a temperature is sensed by the thermistor at a distance greater then 1.8 mm from the shaft of the catheter, it generally accurately represents the temperature of the blood flowing within the vessel and is not unduly influenced by the temperature of the catheter shaft. It may be possible to advance the probe too far, however. For example, if the catheter is in a vessel and the sensor is too far away from the shaft, the sensor in may impact on the vessel wall. Likewise, if the sensor portion of the temperature probe is extended too far out of the temperature probe lumen, it may prolapse back onto the catheter shaft and the temperature sensed may be significantly influenced by the temperature of the catheter shaft.
[0091] The location of the distal exit opening in the temperature probe lumen along the length of the catheter is also important. When the catheter is used for whole body cooling in the inferior vena (IVC) the catheter is generally inserted through an introducer sheath into the femoral vein and advanced so that the balloon is located entirely in the IVC. So that the cooling may be maximized, it is desirable that the balloon occupy as much as possible of the IVC. That means that the shaft of the catheter is located to a large extent in the femoral vein, a much smaller vein than the IVC. In fact the shaft extends all the way back through the introducer sheath. The blood in the introducer sheath tends to flow very little if at all, and therefore to be greatly influenced by the temperature of the catheter shaft. Thus it is desirable that the temperature sensed be that of the blood in the IVC and not in the femoral vein or in the introducer sheath. Yet if the sensor is too close to the balloon, the effect heat exchange region, it is likely to be greatly influenced by the temperature of the heat exchange fluid. Therefore the exit of the temperature probe lumen is desirably as close to the balloon as possible to ensure that it is measuring the temperature of the blood in the IVC and not the femoral vein, or the introducer sheath, and yet far enough away from the balloon to accurately sense the temperature of the blood and not be unduly influenced by the temperature of the heat exchange fluid in the balloon. It has been found that if the probe lumen exit slot 30 is located about 0.5 cm or more proximal of the heat exchange region, that this is generally acceptable. (The closeness of the probe tip to the expanded balloon also has the important advantage of allowing the balloon to somewhat act as a bumper to shield the tip of the probe from contacting the wall of the vessel.)
[0092] Likewise, the length that the probe extends from the exit opening in the lumen is important. Besides not prolapsing on the catheter shaft, it is important that the probe not extend far enough to lay against the balloon. Again, in this embodiment, it has been found that generally a gentle J shaped extension resulting in the thermistors being extended 1.8-1.0 mm from the shaft is desirable.
[0093] As can be seen in FIG. 4, the end of the temperature probe lumen preferably includes a ramp 31 leading up to the opening. Thus, when the thermistor portion of the temperature control probe encounters the ramp, the ramp directs the thermistor up and through slot 30 into the blood stream. The end of the probe is generally shaped in a gentle J shape in a manner well know to those in the art of guide wires and like probes, and is constrained in a relatively straight shape within the temperature probe lumen. Once extended out of the lumen through the ramp, it assumes its substantially J-shape.
[0094] It will be appreciated that a J-shaped wire that is round may be rotated, and the distal tip of the probe may not be directed out away from the catheter. In order to assure proper orientation of the J tip away from the catheter, slot 30 is preferably in the form of a flat slot. The portion of temperature probe 20 that mates against this flat surface when the probe is extended is preferably in the form of a substantially flat probe. Thus, when the flat portion of the temperature probe encounters the flat ramp, the shape of the ramp orients the probe to ensure that the substantially J-shape extends outward away from the catheter shaft.
[0095] Accordingly, the catheter is inserted into a subject's blood vessel with the temperature probe retracted and the thermistors on the end of the probe within the temperature lumen in an undeployed state. By extending the temperature probe forward, the thermistor tip is moved through the slot and the temperature is thus deployed into the subject's blood stream.
[0096] Since the catheter is within a blood vessel, tip 40 of the thermistor preferably comprises an atraumatic tip. This helps prevent puncturing of the blood vessel or irritating the endothelium of the vessel if the temperature control probe encounters the wall of the blood vessel.
[0097] Other embodiments of an on-board temperature probe are clearly within the contemplation of this invention. With reference to FIG. 3A, it can be seen that instead of having a lumen within the catheter for a movable temperature probe as shown in FIG. 2A, a tube with a channel 50 may extend along the exterior of the catheter shaft. With the embodiment illustrated in FIG. 3A, the deployable temperature probe may be deployed into its substantially J-shape through a slot as illustrated in FIG. 3B.
[0098] FIG. 5 illustrates alternative embodiment of the catheter system and the on-board temperature probe. The temperature probe 150 is fixedly contained within a temperature probe channel 152 and held in place by plug 154. The distal portion 156 of the temperature probe is upwardly biased so that if unrestrained it assumes a curved shape 156 with the tip extending outward away from the catheter body. A biodegradable band such as a suture 60 that may be rapidly dissolvable in blood restrains the distal portion against the shaft of the catheter. When the catheter is placed into the blood stream, the restraining band is dissolved and the distal portion of the probe assumes its curved configuration 156 with the temperature sensors in the tip 158 extending outward from the catheter shaft. Preferably this assumes a gentle J shape as described above to adequately locate the temperature sensor away from the catheter shaft but to have an atraumatic configuration. The distal portion of the probe may have a mechanical bias such as a fixed shape with spring-like bias, or it may have a temperature sensitive bias. That is, it may have a straight shape when at room temperature, but be made of a shape memory material such as nitonol or various temperature memory plastics, so it is straight at room temperature but assumes a curved shape when it is warmed to body temperature by the blood. If this type of shape memory material is used, a restraining band need not be used, although it might also be used as an additional restraint. It should be noted that whenever a probe tip is described herein as biased in a particular configuration, that bias may be a permanent mechanical bias or it may be a bias that is temperature dependent as described herein, and both are within the contemplation of this invention.
[0099] FIG. 6 illustrates another embodiment wherein the temperature probe is fixed in its axial orientation, and uses a pull wire mechanism to deploy the distal portion of the temperature probe away from the catheter shaft. In this embodiment, two wires 70, 71 are used to deploy the temperature probe into the bloodstream. The distal portion is configured, either as a spring (not illustrated) or a solid portion with cut-out sections. The wires are attached to the tip at a location slightly off-center. By pulling on one wire or the other, the top of the distal portion is compressed, and the lower portion expands to deploy the temperature probe into the bloodstream, preferably in a gentle, substantially J-shape. Reversing the process may return the probe to its generally straight configuration and thus minimize its profile for insertion and withdrawal. Various mechanism for activating the pull wire or pull wires are well known in the art and are not illustrated here.
[0100] Another embodiment of an on-board, deployable probe is illustrated in FIGS. 8A and 8B. An outwardly biased member comprised of two legs 162, 164 which may be a unitary member is provided at an appropriate location proximal of the heat exchange region. The temperature sensor, such as a thermistor 166 is located in the central portion between the two legs, so that when they assume their outward configuration (FIG. 8A) the temperature sensor is held outward away from the catheter shaft. In this embodiment, the legs may be rigid, for example a flat piece of plastic, and may be provided with a slot 168 in which to retract when compressed. In this Figure the slot is shown as provided for the forward leg, but it is equally acceptable for the forward leg to be fixed and the rear leg to retract when compressed. The upwardly biased member 162/164 may in fact be a curved member and not two distinct legs, as will be readily appreciated by those in the art. Alternatively, the upwardly biased member 162/164 may simply be compressible into a flat configuration and not a slidable configuration as illustrated.
[0101] The temperature sensor, such as thermistor 166, is attached to two signal carrying wires 170, 172 that carry the temperature sensing signal to the exterior plug 96. As stated previously, it is important that the wires be thermally insulated so that the temperature sensed by the thermistor 166 is that of the blood flowing over it and is not a temperature of the catheter shaft conducted up the wires 170, 172.
[0102] The deployed sensor of this embodiment has the advantage that nothing need be done to deploy the on-board sensor. That is, it is essentially always deployed, but will compress down against the shaft upon insertion through an introducer sheath so that it assumes a small profile for insertion, but will immediately spring back out when unconstrained in the bloodstream.
[0103] Yet another embodiment is depicted in FIGS. 9A and 9B. In this embodiment, a movable temperature probe 178 with an upwardly biased distal portion 180 is placed in a temperature probe lumen with an open window 174 and a closed distal end 176. Prior to being deployed the distal end of the probe is retained within the distal end 176 of the lumen. When the probe is withdrawn a short distance (shown in FIG. 9B) the upwardly biased portion exits through the window and assumes the curved configuration that orients the temperature sensor 182 away from the catheter shaft. When the catheter is subsequently withdrawn, the temperature probe will naturally fold down against the catheter shaft as it is being drawn through the introducer sheath.
[0104] When ever the deployment of a temperature probe is accomplished by the axial movement of the probe, the amount of axial movement may be important in order to orient the temperature sensor the proper distance away from the catheter shaft. One method of doing so is shown in FIGS. 18A and 18B. An indicia, such as a marker band 184, may be located on the distal end of the temperature probe, and when that marker is at the proper location that would indicated the amount of axial movement of the temperature probe. In the example illustrated, the probe is deployed by withdrawing the temperature probe, and the amount of withdrawal necessary is indicated when the marker band just clears the exit port 86. Of course, the same effect may be had if the marker band is used to indicate the advancement of the temperature probe as in FIG. 1; the marker would be placed farther up on the distal end of the probe and the correct amount of advancement indicated when the marker band is at the correct location relative to the exit port 86. The probe may then be locked in place in any of various means; for example affixing a keyed or barbed channel with a mating shape on the probe surface.
[0105] Other means of ensuring the correct amount of axial movement may be seen in FIGS. 10A and 10B and 17A and 17B. In 10A a temperature probe with a large distal portion is located in a temperature probe channel as in FIG. 9A. The proximal end of the large distal portion of the temperature probe is too large a diameter to fit within the proximal temperature probe channel 188 and therefore when the temperature probe is withdrawn, it will only withdraw until the probe is withdrawn a certain distance. The probe distal portion then assumes its J shape, either because of its permanent bias or temperature based memory shape.
[0106] In this embodiment, the distal portion of the channel 188 must be large enough to accept the distal portion of the probe, yet the proximal portion of the channel 186 must be small enough not to accept the proximal end of that portion of the temperature probe. If the proximal portion of the probe tip is tapered or otherwise of increased diameter, a channel of the same diameter could be used for both sections which has obvious manufacturing advantages. Another way in which this could be accomplished as shown in FIGS. 17A and 17B. In this example, a section of enlarged diameter 190 is contained on the temperature probe in the section located in the window 174. When the probe is withdrawn, it can only be withdrawn until the enlarged section contacts the proximal edge of the window. In this way the exact amount of axial movement of the probe can be predetermined, and the exact shape of the distal portion determined for placement of the temperature sensor the appropriate distance from the catheter shaft.
[0107] Another embodiment for accomplishing this precise amount of axial movement is shown in FIGS. 16A and 16B. In this embodiment, the probe has a location of sharp increase in diameter 192, and the distal end of the temperature probe lumen has a flap 194 that is biased down against the catheter shaft. When the temperature probe is advanced it can exit under the flap 194, but when it is withdrawn, it cannot be withdrawn past the location of increased diameter. In this way the probe may be deployed forward, and then pulled back to the correct, predetermined position and no farther.
[0108] These methods of determining position of the probe after deployment may, of course, be used alone or in combination with each other.
[0109] Another embodiment of an on-board temperature sensor that has one diameter, for insertion for example, and another diameter where the temperature sensor is held away from the catheter shaft is depicted in FIGS. 13A, 13B and 14. In this embodiment, the temperature sensor 196, such as a thermistor is located on a balloon 202. Insulated wires 198, 199 conduct temperature signals from the thermistor outside the patient's body to a controller. An inflation channel 200 permits the introduction of inflation medium for example saline or CO.sub.2 to inflate the balloon. The balloon may be, for example, a non-compliant PET balloon that has a predetermined shape and size. When fully inflated, this holds the temperature sensor a predetermined distance out into the bloodstream. This has the advantage of permitting some insulation, for example the use of an insulating inflation medium such as CO.sub.2 and providing a very atraumatic means of locating the temperature sensor away from the catheter. The presence of the balloon just upstream of the heat exchange region may have an additional benefit of causing mixing eddies in the fluid stream (blood stream) that may further enhance heat exchange between the heat exchange region and the blood.
[0110] Two balloons may be provided as shown in FIGS. 15A and 15B. In FIG. 15A each balloon 204, 206 is provided with a temperature sensor 208, 210. This may provide safety through redundancy or may provide for temperature measures at different locations. The two balloons may be located a different locations along a common lumen 212 and therefore the probe connecting wires 214, 216 for carrying the temperature signal may be located in the common lumen, and likewise the same lumen may serve as the inflation lumen for both balloons.
[0111] In 15B, a temperature probe may be located on a wire, string, or other member 218 suspended between two balloons. This has the advantage of allowing the access to the temperature sensor from outside the catheter. In this situation it might be desirable to have the wires from the sensor travel outside the body through an external channel or not encased in a channel at all rather than locate them in the inflation channel.
[0112] Another embodiment is shown in FIGS. 12A and 12B. In this embodiment, a temperature probe 300 is in the form of a polymide tube. The polyimide tube is contained in a temperature probe lumen 302. The lumen has a window 304 located at a location along the catheter for example about 3 cm proximal to a heat exchange balloon. The probe is fixed in the probe lumen proximal of the window by, for example, adhesive 303.
[0113] At the location of the window the polyimide tube is crimped 306. Near the location just proximal of the crimp, a thermister 308 is located in or on the tube. A second thermister 309 may be located just distal if the crimp to provide redundancy. Connector wires 314, 316 run from the thermisters to the plug the proximal end of the tube outside the patient's body.
[0114] The probe tube has two openings 318,320 one on each side of the crimp. A pull wire 310 is affixed at the distal end 312 of the tube, and runs from that point of attachment inside the probe tube, out of the first opening 318, along the side of the probe tube, back into the tube through the second opening 320, and from there runs the length of the tube and is accessible to the operator at the proximal end (not shown).
[0115] This embodiment, when undeployed, the temperature probe lies flat with sensors 308, 309 within the outer profile of the catheter and thus is insertable within the same size introducer sheath. Once located in the desired location in the vasculature, the operator pulls the pull wire 310 which slides the distal portion of the probe tube backwards and causes the tube to bend at the crimp 306 and depoly the sensor through the window up and away from the catheter.
[0116] When the catheter is to be withdrawn, the pull wire may be pushed forward to once again cause the probe to lie flat in the probe lumen 302. In addition, the force of pulling the catheter back through the sheath can push in the deployed portion of the probe back down through the window and essentially return it to the undeployed position. Alternatively, or in addition, a biasing member such as a spring or elastomeric string may attach the distal end of the tube 300 to a distal location in the probe lumen 302 so that the probe tube is pulled straight with the crimped portion within the window section of the tube unless the pull wire is withdrawn.
[0117] In this configuration, at the proximal end, a method of affixing the pull wire in the pulled configuration in a manner commonly known in the art, will allow the wire to be retracted, affixed in the retracted position which will fix the sensor in the deployed position. As discussed previously, methods of affixing the pull wire at a specific axial location will assure the proper amount of bending at the crimped location for proper deployment of the probe.
[0118] When the catheter is to be withdrawn, various devices for releasing the pull wire allow the catheter to be withdrawn with the probe in the undeployed configuration.
[0119] Similarly in FIGS. 12A and 12B an arm 222 hinged at an attachment to the catheter 224 may be raised away from the catheter body with a push wire, or relaxing of a restraining wire if the hinge has an upward bias.
[0120] Those skilled in the art will understand that other mechanisms and/or arrangements may be used to deploy the temperature probe into the bloodstream.
[0121] Although the present invention has been described with reference to specific exemplary embodiments, it will be appreciated that it is intended to cover all modifications and equivalents within the scope of the appended claims.
