Abstract:
Disclosure is provided for apparatus and methods to control the temperature of fluids being administered to patients. The apparatus consists of an I.V. reservoir, fluid administration or I.V. tubing, an in-line heater, a heater controller, a temperature sensor located near the patient and feedback circuit connecting the temperature sensor to the heater controller. A method is disclosed which provides for overheating of the fluid so that it cools down to the desired temperature (usually body temperature) by the time it reaches the patient.  
     In another embodiment, apparatus is disclosed for providing distributed heat to fluids being administered to patients. This apparatus includes heating channels or elements running along a length of the fluid administration tubing. These heating elements are controlled by a controller, which is attached to a temperature sensor, preferably located near the patient. The key advantages of this system include low cost, ease of use and reduced overheating of fluids prior to delivery to the patient. Such overheating could result in degradation of the fluids being delivered to the patient.

Description:
RELATED APPLICATIONS  
       [0001]    This application is a continuation-in-part of, and claims priority benefit to, U.S. application Ser. No. 09/838,902, filed on Apr. 19, 2001, entitled “METHOD AND APPARATUS FOR FLUID ADMINISTRATION WITH DISTRIBUTED HEATING”, the entirety of which is hereby incorporated herein by reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    This invention relates to improvements in devices to control the temperature of fluids administered to patients.  
         BACKGROUND OF THE INVENTION  
         [0003]    Patients often require administration of fluid and blood products at or near body temperature in order to prevent hypothermia from occurring. Such fluid administration is also known as intravenous (I.V.) fluid administration. This is especially important during anesthesia, surgery, shock and trauma when body temperature may be reduced by exposure or by interference with the body&#39;s thermoregulatory mechanisms. Hypothermic patients often experience uncontrolled shivering. Patient recovery is often complicated and extended by hypothermia.  
           [0004]    Patients requiring blood, or blood products such as serum, are often in a state of circulatory shock. Blood is generally delivered from blood banks cold and is typically not adequately warmed to body temperature prior to administration due to time limitations of emergency circumstances. This situation compounds the problems facing the patient. Patient mortality and morbidity could be substantially reduced by delivery of blood and other fluids at proper body temperature. Intravenous fluids delivered to patients not include blood and blood products but also include dextrose, other sugars, saline, drugs, and the like.  
           [0005]    Current methods of controlling the temperature of intravenous fluids and blood are in-line fluid warmers and external bulk fluid warmers. In-line fluid warmers heat fluids by applying heat directly, using a heating element, to fluid as it passes from the fluid reservoir to the patient. These heaters are located a substantial distance from the patient and temperature loss is substantial by the time the fluid reaches the patient.  
           [0006]    External bulk fluid warmers heat the I.V. fluid bottle or bag prior to administration to the patient. The bottles or bags are removed from the heaters and placed next to the patient on an I.V. stand as they are needed. The bottle or bag is attached to a fluid administration set, consisting of a drip chamber, fluid administration (I.V.) tubing, roller clamps and I.V. cannula. The fluid passes from the reservoir to the patient through the fluid administration set under the force of gravity. As the fluid passes through the administration set, it loses heat. This temperature attenuation is exacerbated by low flow rates because of increased fluid dwell time in the I.V. tubing. Because of its long length and corresponding large surface area, substantial heat loss to the room occurs in the I.V. tubing. In addition, the warm fluid bag or bottle cools down over time and will, given enough time, eventually reach ambient room temperature.  
           [0007]    Although insulated lines help the problem, temperature losses remain substantial. Typical warming systems are cumbersome, bulky and not sufficiently user-friendly for frequent use. The limitations of existing technology force clinicians to deliver cool and unregulated intravenous fluids and blood to their patients. Although not a preferred practice, there is no convenient method for regulating the temperature and delivery of intravenous fluids and blood products to patients.  
           [0008]    New devices, procedures, systems, and methods are needed for inexpensively and conveniently administering heated fluids to patients in such a way that hypothermia is not exacerbated. Such devices and procedures are particularly important in any medical setting including in-hospital, pre-hospital, outpatient, military, and the emergency department.  
         SUMMARY OF THE INVENTION  
         [0009]    The present invention discloses an improved device and method for controlling the temperature of fluids delivered to a patient. The invention is a system that ensures that fluids delivered to the patient reach the patient at the desired temperature, generally body temperature or 37.0 degrees centigrade. By delivering fluids at or near body temperature, the risk of creating or aggravating hypothermia in a patient is minimized.  
           [0010]    A temperature measurement probe is located at the end of the I.V. tubing nearest the patient. This temperature measurement is taken near the patient and the information is fed back through wires or by wireless methods to a circuit that controls an in-line heating element that heats the fluid. In this way, temperature losses in the I.V. tubing may be compensated by overheating the fluid so that it reaches the patient at the desired temperature.  
           [0011]    In another embodiment of the invention, the feedback from the temperature probe is transmitted through wires, which are integral to the I.V. tubing. The transmission line wires may be embedded or co-extruded, for example, within the tubing. A connector is attached to the transmission line wires in the tubing. This connector allows transmission of information to the controller through electrical leads, attached to the connector. In this manner, cost is reduced and the system is simplified so that no additional components need be set up by the nurse or medical practitioner.  
           [0012]    In yet another embodiment, insulated tubing may be used to minimize heat loss in the I.V. tubing and, thus, minimize the amount of overheating required of the in-line heater.  
           [0013]    In the preferred embodiment, the in-line heating is accomplished by pumping heated fluid through channels or lumens that run parallel and adjacent to the fluid administration channel in the I.V. tubing. In this way, the heating is distributed along the length of the I.V. tubing so temperature gradients are reduced. This embodiment requires a fluid pump, heater, controller, and temperature probe as well as heat exchange tubing, a heating manifold, an intravenous (I.V.) cannula, and at least one fluid shunt.  
           [0014]    In yet a further preferred embodiment, the heating channels are located radially exterior to the fluid administration channel. In this way, the heating channels not only heat, but they also buffer, or insulate, the fluid administration channel from ambient temperatures surrounding the I.V. tubing.  
           [0015]    In another embodiment, the heating channels, manifold, shunt and delivery tubing are pre-filled with heat exchange fluid so that messy filling and handling are not required. In another embodiment, an additional insulation layer may be disposed radially outward of the heating channels to minimize heat loss to the environment. In yet another embodiment, the distributed heating is accomplished by resistive or Ohmic heating of a metal or ceramic element that runs along the length of the I.V. tubing.  
           [0016]    In another embodiment, the an apparatus is provided for administration of medical fluids to a patient, the apparatus including a reservoir containing a volume of I.V. fluid, a warmed volume of heating fluid, a length of fluid administration tubing comprising an I.V. fluid lumen, and a heating lumen, wherein the heating lumen runs parallel to the I.V. fluid lumen, and wherein the I.V. fluid flows in the I.V. fluid lumen toward the patient, and the warmed heating fluid flows in the heating lumen. The apparatus further includes an I.V. cannula connected to the distal end of the I.V. fluid lumen, through which I.V. fluid is injected into the circulatory system of a patient. In this embodiment, the I.V. fluid is warmed substantially only along the length of the fluid administration tubing.  
           [0017]    Another aspect of the invention is a method of delivering temperature controlled medical fluids to a patient which includes providing a volume of I.V. fluid to be administered to a patient, delivering the I.V. fluid to the patient through a length of fluid administration tubing that includes an I.V. fluid lumen, and a heating lumen. In this embodiment, the volume of I.V. fluid is delivered to the patient through the I.V. fluid lumen, heating a heating fluid to generate a warmed heating fluid, wherein the warmed heating fluid is heated by a heating fluid source, and circulating the warmed heating fluid through the heating lumen of the fluid administration tubing to transfer heat to the I.V. fluid. In this embodiment, the I.V. fluid is only heated along substantially the length of the fluid administration tubing.  
           [0018]    Another embodiment is an apparatus for fluid administration to a patient comprising a means for providing a volume of intravenous fluid to be administered to the patient, a means for flowing said intravenous fluid along a length of tubing into the patient, and a means for heating the intravenous fluid only along the length of tubing as it flows toward the patient. The I.V. fluid is not heated in a heat exchanger that is separate from the fluid administration tubing, but rather, it is heated within the fluid administration tubing itself. The fluid administration tubing is configured to maximize the longitudinal distance during which the I.V. fluid is heated and to minimize heat losses while flowing through the fluid administration tubing.  
           [0019]    A key advantage of this system is that fragile fluids such as blood and blood products are not overheated prior to delivery to the patient. Another advantage of the system is that it may be inexpensively fabricated and it may be provided in a convenient configuration that encourages its use. The set allows for disposability, pre-sterilization, low cost and convenient operation. The set further permits easy attachment to control consoles using simplified attachment and a minimum of connections.  
           [0020]    For purposes of summarizing the invention, certain aspects, advantages and novel features of the invention are described herein. It is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.  
           [0021]    These and other objects and advantages of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0022]    A general architecture that implements the various features of the invention will now be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate embodiments of the invention and not to limit the scope of the invention. Throughout the drawings, reference numbers are re-used to indicate correspondence between referenced elements.  
         [0023]    [0023]FIG. 1 shows a system for fluid administration utilizing the temperature monitoring and control elements, according to an embodiment of the invention;  
         [0024]    [0024]FIG. 2 shows a length of tubing used for fluid administration, according to an embodiment of the invention. The tubing includes a through lumen for fluid administration and four outer lumens;  
         [0025]    [0025]FIG. 3 shows a system for fluid administration utilizing distributed heat exchange elements, according to an embodiment of the invention;  
         [0026]    [0026]FIG. 4 shows a length of tubing used for fluid administration, according to an embodiment of the invention. The tubing includes a through lumen for fluid administration and two outer lumens for carrying fluids or for insulation.  
         [0027]    [0027]FIG. 5A shows a longitudinal cross-section of a heating manifold, which is attached to the distributed heat exchange fluid administration tubing, according to an embodiment of the invention;  
         [0028]    [0028]FIG. 5B shows a lateral cross-section of a heating manifold, which is attached to the distributed heat exchange fluid administration tubing, according to an embodiment of the invention;  
         [0029]    [0029]FIG. 6 shows a cutaway view of the flow shunt located at one or more ends of the distributed heat exchange fluid administration tubing, according to an embodiment of the invention;  
         [0030]    [0030]FIG. 7 shows a lateral cross-section of another embodiment of distributed heat exchange fluid administration tubing with an extra insulation layer on the exterior, according to an embodiment of the invention; and  
         [0031]    [0031]FIG. 8 shows a length of tubing used for fluid administration, which includes a resistive heating element, according to an embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0032]    In accordance with one or more embodiments of the present invention, a plurality of embodiments of a fluid administration system is described herein. In order to fully specify this preferred design, various embodiment specific details are set forth. It should be understood, however that these details are provided only to illustrate the presented embodiments, and are not intended to limit the scope of the present invention. The invention herein described is a fluid administration system that heats the fluids and ensures the fluids are delivered to the patient at the desired temperature, typically normal body temperature. Fluids to be administered to a patient include, but are not limited to, blood and blood products, saline, lactated ringers solution, sugar solutions, drugs, and the like.  
         [0033]    Throughout the text, referral is made to tubing or cannulae, which are axially elongate structures with external surfaces and internal lumens capable of holding structures or stagnant or flowing fluids. As one skilled in the art of medical devices will appreciate, the axially elongate structure may be defined as having a proximal end and a distal end. When referring to the device, the proximal end is that end axially furthest from the patient and the distal end is that end axially closest to the patient.  
         [0034]    [0034]FIG. 1 illustrates one embodiment of a fluid administration system of the present invention comprising a fluid reservoir, or an I.V. bag  108  containing a volume of fluid  110 , a length of fluid administration tubing  112 , an in-line heater  114 , a delivery pump  116 , an I.V. cannula or needle  118 , and a patient  120 . The fluid administration system additionally comprises a controller  122 , a heater power/control line  124 , a delivery pump power/control line  126 , a temperature probe  128 , and a temperature feedback line  130 . The fluid administration system may optionally comprise a drip chamber  142 , an injection port  222  and an adjustable clamp  224 .  
         [0035]    Referring to FIG. 1, fluid  110  from the fluid reservoir  108  travels, via the tubing  112 , through the optional drip chamber  142 , to the in-line heater  114  where it is heated. From the in-line heater  114 , the fluid  110  travels via the tubing  112  to the delivery pump  116  where it is pumped at a set flow rate. From the delivery pump  116 , the fluid  110  travels, via the tubing  112 , through the optional injection port  222  and the adjustable clamp  224 , to the I.V. cannula  118  that is inserted into the patient  120 . Thus, the patient  120  receives the fluid  110 . The temperature probe  128  is inserted into the I.V. tubing  112 , near the I.V. cannula  118 , so that it can sense the temperature of fluid  110 , and is connected to the controller  122  through the temperature feedback line  130 . The controller  122  is also connected to the in-line heater  114  and the delivery pump  116  through the heater power/control line  124  and the delivery pump power/control line  126 , respectively. The I.V. cannula  118  is generally a needle or a short tube that is placed through or over a needle or guidewire to route intravenous fluids into the circulatory system or intramuscular tissue of the patient. The I.V. cannula  118  is generally not used to route intravenous fluids to a location remotely disposed from the puncture or entrance site where the I.V. cannula  118  is inserted into the patient  120 .  
         [0036]    The operator sets the flow rate of the fluid  110  at the controller  122 . The controller  122  transmits power and flow rate commands to the delivery pump  116  through the delivery pump power/control line  126 . The operator also sets the temperature of the fluid  110  at the controller  122 . The operator specifies the temperature of the fluid  110  to be administered to the patient  120 . The fluid temperature and/or flow rate could also be pre-set or automatically set without requiring operator intervention. The controller  122  transmits power and temperature adjustment commands to the in-line heater  114  through the heater power/control line  124 . The temperature probe  128  measures the temperature of the fluid  110  immediately prior to delivery of the fluid  110  to the patient  120 . This temperature information is sent through the temperature feedback line  130  to the controller  122  where it is processed. The controller  122  transmits temperature adjustment commands to the in-line heater  114  to maintain the selected fluid temperature at the patient  120 . In this manner, the fluid administration system compensates for temperature losses in the fluid administration tubing  112  and assures the patient  120  will receive fluid  110  at the specified temperature. Note that the temperature probe  128  may be a standard commercial thermocouple, thermister or other temperature-measuring device. The delivery pump  116  is optional and the system could work as well using standard gravity feed.  
         [0037]    [0037]FIG. 2 illustrates one embodiment of the length of fluid administration tubing  112  of the present invention. The tubing  112  is circular in cross-section and comprises a through lumen  132 , an inner wall  134 , a plurality of outer lumens  136 , an outer wall  138  and a plurality of webs  140 . Optionally, the tubing  112  comprises the temperature feedback line  130 . The warmed fluid  110  to be administered to the patient  120  travels through the through lumen  132 . The outer lumens  136  insulate the through lumen  132  from the ambient temperature and help to reduce the fluid temperature losses in the fluid administration system. The tubing  112  can be extruded from plastic such as polyvinyl chloride, chlorinated polyvinyl chloride, polyethylene, polypropylene, polyurethane and the like. Typically, the plastic is uncolored and transparent to allow for visualization of the fluid. The tubing  112  may be rigid or flexible. Ultraviolet light resistant additives or blue colorants may also be added to compensate for color changes that occur during gamma or E-beam sterilization. The tubing  112  can also be a simple single lumen tube.  
         [0038]    Referring to FIGS. 1 and 2, the temperature feedback line  130  can optionally be embedded in the fluid administration tubing  112 . The temperature feedback line  130  may be fabricated from copper, steel or other conductive metal. Via a connection (not shown) at or near the in-line heater  114 , the temperature feedback information is transmitted on the heater power/control line  124  to the controller  122  where the information is used to control the heating of the fluid  110 . This operates the same and produces the same results as having a physically independent temperature feedback line  130  as shown in FIG. 1. However, embedding or coextruding the temperature feedback line  130  in the fluid administration tubing  112  results in a simpler system.  
         [0039]    Additional features of the system could include pressure, optical or flow sensors to warn the controller  122  if the fluid administration reservoir  108  is empty. Such a system could cause controller  122  to shut off delivery pump  116  so as not to cause damage to the system or pump air into the patient  120 .  
         [0040]    [0040]FIG. 3 shows a preferred embodiment of the fluid administration system. In this embodiment, the fluid  110  to be administered to the patient is not heated with an isolated in-line heater, but is heated by distributed temperature transfer from a warmed heat exchange fluid. The fluid administration system of FIG. 3 comprises the fluid reservoir  108 , the optional drip chamber  142 , a length of tubing  156 , the delivery pump  116 , a heat exchange manifold  144 , a length of heat exchange fluid administration tubing  146 , a flow shunt  148 , the I.V. cannula  118 , and the patient  120 . The heat exchange manifold  144  comprises an input port  160  and an output port  162 . The fluid administration system additionally comprises the controller  122 , a heat exchange fluid heater  150 , a circulating pump  152 , a length of circulation tubing  230  and a volume of heat exchange fluid  158 . The fluid administration system additionally comprises a heat exchange power/control line  154 , a circulating pump power/control line  210 , the delivery pump power/control line  126 , the temperature probe  128 , and the temperature feedback line  130 . Optionally, the fluid administration system could comprise the injection port  222  and the clamp  224  as shown in FIG. 1.  
         [0041]    Referring to FIG. 3, the fluid  110  from the I.V. bag  108  travels through the optional drip chamber  142  to the delivery pump  116  via the tubing  156 . The fluid  110  is pumped from the delivery pump  116  to the heat exchange manifold  144  via the tubing  156 . From the heat exchange manifold  144 , the fluid  110  travels to the flow shunt  148  via the heat exchange fluid administration tubing  146 . The fluid  110  leaves the flow shunt  148  and enters the I.V. cannula  118  that is inserted into the patient  120 . Thus, the patient  120  receives the fluid  110 .  
         [0042]    The temperature probe  128  is located proximate to, at, or near, the I.V. cannula  118  and is connected to the controller  122  through the temperature feedback line  130 . The temperature probe  128  is located to sense the temperature of the fluid  110 , just before the fluid  110  is delivered to the patient  120 . The temperature probe  128  may have a sensing element touching the fluid  110  or it may be separated from the fluid  110  by a layer of adequately heat conductive material such as metal or thin layer of plastic.  
         [0043]    The controller  122  electrically connects to the delivery pump  116  through the delivery pump power/control line  126 . The controller  122  also electrically connects to the heat exchange fluid heater  150  through the heat exchange power/control line  154 . The controller  122  electrically connects to circulation pump  152  through the circulation pump power/control line  210 . The heat exchange fluid heater  150  connects to the circulation pump  152  and the heat exchange manifold  144  through tubing  156 . The circulating pump  152  also connects to the heat exchange manifold  144  through tubing  156 . The heat exchange manifold  144  is located at or near the proximal end of the fluid administration tubing  146 . This permits easier attachment to the tubing  156  and minimizes the length of the tubing  156 . The proximal attachment of the heat exchange manifold  144  further maximizes the length of fluid administration tubing  146  through which the fluid  110  travels before it reaches the patient  120 , thus maximizing heat transfer capabilities of the system.  
         [0044]    The fluid  110  travels through the optional drip chamber  142  to the delivery pump  116  where it is pumped through the heat exchange manifold  144 , the flow-shunt  148 , and the I.V. cannula  118  to the patient  120 . The operator sets the flow rate at the controller  122 . The controller  122  transmits power and flow rate commands through the delivery pump power/control line  126  to the delivery pump  116 . The delivery pump  116  is optional and the apparatus would work as well with standard gravity feed.  
         [0045]    The fluid  110  is not heated by an in-line heater as was described in an earlier embodiment. Within this fluid administration system there exists a closed heat exchange loop that is distributed along at least a portion of the length of the heat exchange fluid administration tubing  146 . This heat exchange loop extends along the fluid administration tubing  146  between the heat exchange manifold  144  and the shunt  148 . Preferably the heat exchange loop extends along substantially most or all of the length of the fluid administration tubing  146  to maximize heat transfer capabilities of the system. The flow shunt  148  is preferably operably connected to the fluid administration tubing  146  proximate to the I.V. cannula  118  or may even be integral to the I.V. cannula  118 , thus maximizing the heat exchange length of the system. The operator sets the temperature of the fluid  110  to be delivered to the patient  120  at the controller  122 . The controller  122  transmits temperature information to the heat exchange fluid heater  150 , through the heat exchange power/control line  154 , which heats the heat exchange fluid  158 . The heat exchange fluid  158  could be stored in a reservoir (not shown) or pre-filled within the circulation tubing  230 .  
         [0046]    Referring to FIG. 3, the heat exchange fluid  158  enters the circulating pump  152  and is pumped to the heat exchange manifold  144  through the heat exchange manifold input port  160  via circulation tubing  230 . The controller  122  transmits flow rate information through the circulating pump power/control line  210  to the circulating pump  152  to control the flow rate of the heat exchange fluid  158 . The heat exchange fluid  158  travels, via the heat exchange fluid administration tubing  146 , separately, parallel and adjacent to the fluid  110  in order to transfer heat to the fluid  110 . At the flow shunt  148 , the heat exchange fluid  158  is directed back around, or shunted, and flows, via the heat exchange fluid administration tubing  146 , separately, parallel and adjacent to the fluid  110  but in the opposite direction. Again, the heat exchange fluid  158  transfers heat to the fluid  110 . When the heat exchange fluid  158  enters the heat exchange manifold  144 , it passes through the heat exchange manifold output port  162  and enters the heat exchange fluid heater  150  via circulation tubing  230 . Once in the heat exchange fluid heater  150 , the heat exchange fluid  158  is reheated and delivered to the circulating pump  152  to circulate through the heat exchange loop again. In this manner, the fluid  110  is heated to the specified temperature.  
         [0047]    Referring to FIG. 3, the fluid administration tubing  146  has an overall outer diameter of between 0.01 and 0.75 inches and preferably between 0.1 and 0.5 inches. The length of the fluid administration tubing  146  between the manifold  144  and the shunt  148  is between 4 and 100 inches, preferably between 10 and 50 inches and most preferably between 20 and 40 inches. The overall length of the fluid administration tubing  146  proximal to the manifold  144  is long enough to reach the reservoir  108 , generally between 1 inch and 40 inches, and preferably between 1 and 10 inches. The length of the fluid administration tubing  146  between the shunt  148  and the I.V. cannula  118  should be as short as possible, generally between 0 and 10 inches and preferably between 0 and 2 inches.  
         [0048]    To further clarify the heat exchange process, refer to FIGS. 4, 5 and  6 . FIG. 4 illustrates the length of heat exchange fluid administration tubing  146 . The heat exchange administration tubing  146  is circular in cross-section and comprises a through lumen  164 , a set of at least two outer lumens  166 , an inner wall  168 , an outer wall  170 , and a set of at least two webs  172 . Optionally the tubing  146  comprises the temperature feedback line  130 .  
         [0049]    [0049]FIG. 5A illustrates the longitudinal cross-section and FIG. 5B illustrates the lateral cross-section of the heat exchange manifold  144 . The heat exchange manifold  144  comprises the input port  160 , the output port  162 , a through lumen  172 , an input chamber  174 , an output chamber  176 , a set of webs  202 , a delivery fluid administration tubing connector  178 , and a heat exchange fluid administration tubing connector  180 . The input chamber  174  is separated from the output chamber  176  by the webs  202 .  
         [0050]    [0050]FIG. 6 shows a cross-sectional cut away view of the flow shunt  148 . The flow shunt  148  comprises a through lumen  182 , a set of at least two outer lumens  184 , an inner wall  186 , an outer wall  188 , a set of at least two ribs  190 , a return chamber  192 , a flow shunt connector  198 , a flow diverter  200  and a through lumen extension  194 . The ribs  190  that separate the outer lumens  184  from each other are broken in the middle of the flow shunt  148  to create the return chamber  192 .  
         [0051]    Referring to FIGS. 3, 4, and  5 , the warmed heat exchange fluid  158  is pumped through circulation tubing  230  into the heat exchange manifold input port  160  and enters the input chamber  174 . The heat exchange fluid administration tube  146  is connected to the heat exchange manifold  144  at the heat exchange fluid administration tubing connector  180 . The through lumen  172  of the heat exchange manifold  144  and the through lumen  164  of the heat exchange fluid administration tubing  146  are aligned. Likewise, the output chamber  176  of the heat exchange manifold  144  aligns with one of the outer lumens  166  of the heat exchange fluid administration tubing  146  and the input chamber  174  of the heat exchange manifold  144  aligns with the other outer lumen  166  of the heat exchange fluid administration tubing  146 . Similarly, the heat exchange manifold  144  is connected to the tubing  156  through the delivery fluid administration tubing connector  178  and a delivery fluid lumen of the tube  156  is aligned with the through lumen  172  of the heat exchange manifold  144 . The tubing  156  can simply be tubing with a minimum of one lumen, which carries fluid, the fluid administration tubing  112  shown in FIG. 2, or the heat exchange fluid administration tubing  146  shown in FIG. 4.  
         [0052]    Again referring to FIGS. 4, 5, and  6 , the warmed heat exchange fluid  158  exits the heat exchange manifold input chamber  174  and enters one of the outer lumens  166  of the heat exchange fluid administration tube  146 . The through lumens  172  and  164  of the heat exchange manifold  144  and the heat exchange fluid administration tubing  146 , respectively, transport the delivery fluid  110 . As the delivery fluid  110  flows through the through lumen  164  of the heat exchange fluid administration tubing  146 , the warmed heat exchange fluid  158  flows through one of the outer lumens  166 . Heat transfer occurs from the heat exchange fluid  158  to the delivery fluid  110  through the inner wall  168  of the heat exchange fluid administration tubing  146  along the length of the heat exchange fluid administration tubing  146 . The heat exchange fluid administration tubing  146  is connected to the flow shunt  148  through the flow shunt connector  198 . The through lumen  164  of the heat exchange fluid administration tubing  146  aligns with the through lumen  182  of the flow shunt  148 . Likewise, the outer lumens  166  of the heat exchange fluid administration tubing  146  align with the outer lumens  184  of the flow shunt  148 . When the fluids  110  and  158  reach the flow shunt  148 , the delivery fluid  110  passes through the flow shunt  148  through lumen  182 . The I.V. cannula  118  and the temperature probe  128  are connected to the flow shunt  148  at the flow shunt through lumen extension  194 . The delivery fluid  110  at the specified temperature flows into the I.V. cannula  118  where it is delivered to the patient  120 .  
         [0053]    Referring to FIG. 6, the heat exchange fluid  158  enters one of the flow shunt outer lumens  184  through the flow shunt connector  198  and from there the heat exchange fluid  158  is diverted by flow diverter  200  into the return chamber  192  where it is sent back through the other outer lumen  184  of the flow shunt  148 .  
         [0054]    Referring to FIGS. 3, 4, and  5 , the heat exchange fluid  158  flows in the other outer lumen  166  of the heat exchange fluid administration tubing  146 , adjacent to the through lumen  164  of the heat exchange fluid administration tubing  146  carrying the delivery fluid  110 . Again, heat is transferred from the heat exchange fluid  158  across the inner wall  168  of the heat exchange fluid administration tubing  146  to the delivery fluid  110 . The return heat exchange fluid  158  travels through the outer lumen  166  of the heat exchange fluid administration tubing  146  and enters the heat exchange manifold  144  through the heat exchange fluid administration tubing connector  180 . The heat exchange fluid  158  has lost much or all of its warmth and travels from the heat exchange manifold  144  through the heat exchange manifold output port  162  to the heat exchange fluid heater  150  via circulation tubing  230 . Circulation tubing  230  is tubing with at least one lumen. The tubing  230  can be extruded from plastic such as polyvinyl chloride, chlorinated polyvinyl chloride, polyethylene, polypropylene, polyurethane and the like and may comprise an insulation layer. Typically, the plastic is uncolored and transparent to allow for visualization of the fluid. The tubing  230  may be rigid or flexible. Ultraviolet light resistant additives or blue colorants may also be added to compensate for color changes that occur during gamma or E-beam sterilization. The tubing  230  can also be a simple single lumen tube.  
         [0055]    Referring to FIG. 3, the controller  122  sends heating commands to the heater  150  according to the information the controller  122  received from the feedback temperature line  130 . In this manner, the heat exchange fluid  158  circulates along the length of the heat exchange fluid administration tubing  146  and warms the delivery fluid  110  for the patient  120 .  
         [0056]    [0056]FIG. 7 shows a different embodiment of the heat exchange fluid administration tubing  146 . In this embodiment, the outer wall  170  of the heat exchange tubing  146  is covered with a layer of insulation  194 . The insulation  194  reduces the heat loss in the heat exchange fluid  158  and in the delivery fluid  110  to the ambient air. The insulation could be made of polyurethane foam or air-spaced tubing, for example.  
         [0057]    Additionally the fluid administration tubing  112  shown in FIG. 2 could also have an insulation layer  194  like the one shown in FIG. 7.  
         [0058]    [0058]FIG. 8 shows yet another embodiment of the apparatus for heating fluid  110 . The heat exchange apparatus is a length of warming fluid administration tubing  250 . This length of warming fluid administration tubing  250  replaces the in-line heater  114  shown in FIG. 1. The warming fluid administration tubing  250  can also replace the heat exchange fluid loop shown in FIG. 3. The warming fluid administration tubing  250  comprises at least one resistive heating element  196 , a through lumen  252 , a tubing wall  256 . Optionally, the warming fluid administration tubing  250  may comprise the temperature feedback line  130  and at least one electrical lead  254 . Additionally, the warming fluid administration tubing  250  may comprise outer lumens for insulation or a layer of insulating material surrounding the outside of at least a portion of the tubing.  
         [0059]    The resistive heating element or elements  196  are disposed adjacent to the through lumen  252  and are embedded in the wall  256  of the tubing  250 . The resistive heating element or elements  196  are warmed by completing a circuit through the elements  196  and optional electrical lead  254  and creating electrical circuit losses, which occur as heat. If the optional electrical lead  254  is not used, the circuit may be completed by electrically connecting at least two resistive heating elements  196 . The warm resistive element or elements  196  transfer heat to the delivery fluid  110  through the tubing wall  256 . Referring to FIG. 1, the resistive heating elements  196  are electrically connected to the controller  122  by the heater power/control line  124 .  
         [0060]    Referring to FIG. 2, similarly, the resistive heating element  196  could be embedded in the outer wall  138  of the fluid administration tubing  112  and heat fluids in one or both lumens  132  and  136 .  
         [0061]    The resistive element  196  can be fabricated from material such as, but not limited to, nickel-chromium wire or other high-resistance metal. Electrical lead  254  may be fabricated from any low resistance metal such as copper, steel and the like. The metal may be formed into the tubing  250  or  112  during the extrusion process or placed in a special lumen during a secondary operation. Note that the metal heating elements  196  may be fully embedded in the plastic walls  256 ,  134  or  138 , partially embedded in the plastic or fully exposed to the through lumen  252  or  132 , respectively. The metal heating elements  196  may be circular, I-beam, flat, partial cylinders or other shapes.  
         [0062]    At least a portion of the fluid administration system will be sterilized prior to use. Prior to sterilization, the sterilizable portions are to be packaged in single or double aseptic pouches or sealed trays as one skilled in the art of medical device sterilization and packaging will recognize. Such sterilization shall include methods such as ethylene oxide, E-beam, and gamma radiation. The portion that is sterilized shall include, at least, all components, which could come in direct contact with the fluid  110  being administered to the patient  120 . The system presented simplifies attachment between sterile and non-sterile portions to maximize ease of use by minimizing the number of connections to the fluid administration tubing  146  and making all those connections at or near the proximal end of the fluid administration tubing  146 .  
         [0063]    The present invention solves a problem where patients are not currently given medical temperature therapy because of inconvenience and cost. The invention provides for a cost-effective, rapidly implemented system of providing fluids that are warmed to the correct temperature to patients. This is especially important in the emergency and surgical setting where patients lose large amounts of heat and their recovery is impeded by the onset of untreated hypothermia.  
         [0064]    The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. For example, the invention could be used to cool fluid being administered to a patient, rather than heating. This would be accomplished with a chiller unit to replace the heater in the control console. The scope of the invention is therefore indicated by the appended claims rather than the foregoing description. All changes, which come within the meaning and range of equivalency of the claims, are to be embraced within their scope.