ES2278624T3

Heat exchange catheter with discrete heat exchange elements

Abstract

A thermal exchange catheter (24, 50, 100, 150, 180, 350) consisting of: (i) a longitudinal tubular axis of the catheter (52, 104, 164, 182, 218, 240, 306, 358) with a proximal end and a distal end; (ii) a heat exchange region (56, 42, 44, 106, 152, 210) consisting of a plurality of heat exchange elements (58, 58 '', 102, 166, 184, 200, 206, 212, 220, 246, 302, 354), each of said heat exchange elements having an opposite length and ends, each heat exchange element being connected at least one of its ends to the tubular axis of the catheter; characterized in that at least a portion of the length of each heat exchange element is transversely separated from the tubular axis so that, when inserted into a body cavity in which there is a fluid having a body fluid therein, the body fluid surrounds circumferentially each element of heat exchange.

ES2278624T3, drawing sheet 1 — Sheet 1 of 12

Term

Term ended

Projected expiry passed 31 July 2020, 6.1 years ago.

38 claims: 16 independent, 22 dependent

1
ES 2 278 624 T3 REIVINDICACIONES 1. Un catéter para el intercambio térmico (24, 50, 100, 150, 180, 350) que consta de:(i) un eje tubular longitudinal del catéter (52, 104, 164, 182, 218, 240, 306, 358) con un extremo proximal y un extremo distal;(ii) una región de intercambio térmico (56, 42, 44, 106, 152, 210) que consta de una pluralidad de elementos de intercambio térmico (58, 58', 102, 166, 184, 200, 206, 212, 220, 246, 302, 354), teniendo cada uno de dichos elementos de intercambio térmico una longitud y extremos opuestos, estando unido cada elemento de intercambio térmico por al menos uno de sus extremos al eje tubular del catéter;caracterizado porque al menos una porción de la longitud de cada elemento de intercambio térmico está separada transversalmente del eje tubular para que, cuando se inserte en una cavidad corporal en la que haya un fluido que tenga un fluido corporal en su interior, el fluido corporal rodee de forma circunferencial cada elemento de intercambio térmico.
2
Un catéter para el intercambio térmico, como se reivindica en la Reivindicación 1, en el que los elementos diferenciados de intercambio térmico consisten en tubos.
3
Un catéter para el intercambio térmico, como se reivindica en la Reivindicación 1, en el que los elementos de intercambio térmico consisten en filamentos.
4
Un catéter para el intercambio térmico, como se reivindica en la Reivindicación 1, en el que los elementos diferenciados de intercambio térmico consisten en filamentos ciegos unidos al eje tubular del catéter únicamente por un extremo de cada filamento.
5
Un catéter para el intercambio térmico, como se reivindica en la Reivindicación 3, en el que los elementos de intercambio térmico son flexibles y en el que cada uno se ve restringido a lo largo de una porción de su longitud con respecto al eje tubular de modo que se permita que un extremo libre (186) de cada elemento de intercambio térmico vaya a la deriva libremente dentro del fluido corporal.
6
Un catéter, en conformidad con cualesquiera de las reivindicaciones anteriores, en el que uno o más de los elementos de intercambio térmico tienen una vía de flujo para fluidos (58', 80, 130, 312, 314) a través de los mismos.
7
Un catéter para el intercambio térmico, como se reivindica en cualesquiera de las reivindicaciones precedentes, en el que uno o más de los elementos de intercambio térmico tienen una sección transversal no circular (220).
8
Un catéter para el intercambio térmico, como se reivindica en la Reivindicación 6 o en la Reivindicación 7 cuando depende de la Reivindicación 6, en el que el referido eje tubular tiene un conducto para el flujo entrante de fluidos (244) y un conducto para el flujo saliente de fluidos (242) para permitir la circulación de un medio fluido de intercambio térmico a través del elemento de intercambio térmico o de los elementos de intercambio térmico.
9
Un catéter para el intercambio térmico, como se reivindica en la Reivindicación 8, en el que cada elemento de intercambio térmico tiene un orificio para el flujo de entrada (80) en un extremo y un orificio para el flujo de salida (82) en el extremo opuesto, estando en comunicación el orificio para el flujo de entrada y el orificio para el flujo de salida con la vía de circulación.
10
Un catéter para el intercambio térmico, como se reivindica en la Reivindicación 8 o en la Reivindicación 9, en el que cada elemento de intercambio térmico se extiende en una ruta no lineal desde su orificio para el flujo de entrada (80) a su orificio para el flujo de salida (82), teniendo la ruta no lineal al menos un punto de inflexión.
11
Un catéter para el intercambio térmico, como se reivindica en cualesquiera de las Reivindicaciones de la 8 a la 10, ambas inclusive, en el que el catéter incluye un distribuidor de entrada (114, 318) abierto al conducto de flujo de entrada y al orificio de flujo de entrada de cada elemento de intercambio térmico y en el que el catéter incluye un distribuidor de salida (120, 320) abierto al conducto de flujo de salida y al orificio de flujo de salida de cada elemento de intercambio térmico.
12
Un catéter para el intercambio térmico, como se reivindica en la Reivindicación 11, en el que el distribuidor de entrada (114, 318) está ubicado de forma distal con respecto al distribuidor de salida (120, 320).
13
Un catéter para el intercambio térmico, como se reivindica en la Reivindicación 11 o en la Reivindicación 12, en el que los elementos de intercambio térmico consisten en filamentos huecos alargados dotados de extremos opuestos abiertos (Fig. 17) que definen los respectivos orificios de flujo de entrada y de flujo de salida, y en el que el extremo opuesto de cada filamento se comunica con un espacio interior en un sendo distribuidor (114, 120, 318, 320).
14
Un catéter para el intercambio térmico, como se reivindica en cualesquiera de las Reivindicaciones de la 11 a la 13, ambas inclusive, en el que los elementos de intercambio térmico son más largos que la distancia entre el distribuidor de entrada (114, 120) y el de salida (318, 320).
15
Un catéter para el intercambio térmico, como se reivindica en cualesquiera de las reivindicaciones precedentes, en el que el eje tubular del catéter tiene una longitud y la región de intercambio térmico se extiende a lo largo de una distancia que es menor que la mitad de la longitud del eje tubular.
16
Un catéter para el intercambio térmico, como se reivindica en cualesquiera de las reivindicaciones precedentes, en el que la región de intercambio térmico está ubicada en una región distal del eje tubular.
17
Un catéter para el intercambio térmico, como se reivindica en cualesquiera de las reivindicaciones precedentes, que consta además de una región aislante (172, 188) en el eje tubular ubicada de forma proximal con respecto a la región de intercambio térmico.
18
Un catéter para el intercambio térmico, como se reivindica en la Reivindicación 17, en el que la región aislante (172, 188) se extiende la longitud total del eje tubular proximal a la región de intercambio térmico.
19
Un catéter para el intercambio térmico, como se reivindica en la Reivindicación 18, en el que la región aislante (172,188) se extiende aproximadamente un 85-90% de la longitud del eje tubular, y en el que ES 2 278 624 T3 una región de intercambio térmico se extiende sustancialmente a lo largo del resto del eje tubular.
20
Un catéter para el intercambio térmico, como se reivindica en cualesquiera de las Reivindicaciones de la 17 a la 19, ambas inclusive, en el que la región aislante consiste en un globo inflable que rodea el eje tubular.
21
Un catéter para el intercambio térmico, como se reivindica en la Reivindicación 20, en el que el eje tubular está dentro del globo y la región aislante consiste en una pluralidad de separadores interpuestos entre la pared interior del globo y el eje tubular y que los distancian entre sí.
22
Un catéter para el intercambio térmico, como se reivindica en la Reivindicación 20 o en la Reivindicación 21, en el que la región aislante comprende una pluralidad de globos que rodean el eje tubular y una camisa (306) que rodea los globos.
23
Un catéter para el intercambio térmico, como se reivindica en cualesquiera de las reivindicaciones precedentes, en el que cada elemento de intercambio térmico consta de un filamento dotado de un extremo distal y de un extremo proximal, estando sujeto el extremo distal al eje tubular del catéter, e incluyendo además un resorte colocado entre el filamento y el eje tubular y adaptado para comprimirse con la aplicación de una fuerza externa al catéter según se va insertando en la cavidad corporal, y adaptado además para expandirse en ausencia de tal fuerza externa para mantener el filamento a una distancia radial predefinida con respecto al eje tubular.
24
Un catéter para el intercambio térmico, como se reivindica en la Reivindicación 23, en el que cada filamento va fijado además por su extremo proximal al eje tubular del catéter, siendo hueco cada filamento y proporcionando a través de él una vía para el flujo de fluidos para el paso de un medio líquido de intercambio térmico.
25
Un catéter para el intercambio térmico, como se reivindica en cualesquiera de las reivindicaciones precedentes, en el que cada elemento de intercambio térmico consta de un filamento en forma de vara dotado de una nervadura de discontinuidad puesta sobre él.
26
Un catéter para el intercambio térmico, como se reivindica en la Reivindicación 25, en el que la nervadura de discontinuidad de flujo está colocada helicoidalmente en torno del filamento.
27
Un catéter para el intercambio térmico, como se reivindica en la Reivindicación 25, en el que la nervadura de discontinuidad de flujo está colocada de forma circunferencial en torno del filamento.
28
Un catéter para el intercambio térmico, como se reivindica en cualesquiera de las reivindicaciones precedentes, en el que el referido eje tubular del catéter consta de una pluralidad de elementos de intercambio térmico sustancialmente rodeados por una camisa y en el que la región de intercambio térmico consta de porciones de los elementos de intercambio térmico que sobresalen de dicha camisa.
29
Un catéter para el intercambio térmico, como se reivindica en cualesquiera de las reivindicaciones precedentes, en el que hay al menos tres elementos de intercambio térmico.
30
Un catéter para el intercambio térmico, como se reivindica en la Reivindicación 29, en el que los elementos de intercambio térmico están distribuidos uniformemente de forma circunferencial en torno del eje tubular.
31
Un catéter para el intercambio térmico, como se reivindica en cualesquiera de las reivindicaciones precedentes, en el que los elementos de intercambio térmico consisten en globos de paredes muy finas.
32
Un catéter para el intercambio térmico, como se reivindica en cualesquiera de las reivindicaciones precedentes, en el que los elementos de intercambio térmico tienen paredes que permiten una tasa elevada de transferencia conductiva del calor a través de las mismas.
33
Un catéter para el intercambio térmico, como se reivindica en cualesquiera de las reivindicaciones precedentes, en el que los elementos de intercambio térmico son huecos, incluyendo el eje tubular una vía de circulación para fluidos, y estando el interior hueco de los elementos de intercambio térmico en comunicación fluida con la vía de circulación para fluidos.
34
Un catéter para el intercambio térmico, como se reivindica en la Reivindicación 33, en el que cada elemento de intercambio térmico está formado con una vía de flujo coaxial, suministrándose el medio de intercambio térmico a un conducto interior y extrayéndose de un conducto exterior.
35
Un catéter para el intercambio térmico, como se reivindica en la Reivindicación 33, en el que cada elemento de intercambio térmico consta de un circuito de un tubo de un solo conducto, suministrándose el medio de intercambio térmico al conducto del tubo.
36
Un sistema para el intercambio térmico con un fluido corporal que consiste en:(i) un medio líquido de intercambio térmico;(ii) un catéter de intercambio térmico en conformidad con cualesquiera de las Reivindicaciones de la 1 a la 35, ambas inclusive.
37
Un sistema, en conformidad con la Reivindicación 36, constando dicho sistema además de un sensor o sensores fijados al paciente, o insertados en él, para proporcionar retroalimentación sobre la situación del paciente, por ejemplo acerca de la temperatura del paciente.
38
Un sistema, en conformidad con la Reivindicación 37, constando dicho sistema además de un controlador adaptado para controlar el catéter de intercambio térmico basado en la retroalimentación de dichos sensores.

Independent claims38

149 paragraphs in 4 sections, as filed

ES 2 278 624 T3

DESCRIPTION

Catheter for heat exchange with a plurality of heat exchange elements.

Field of the invention

This invention relates broadly to medical devices and more specifically to devices for selectively controlling the temperature of a patient's body or a portion of a patient's body by supplying or extracting heat from the patient's body fluid by using of a catheter for heat exchange incorporating a plurality of differentiated heat exchange elements in the form of filaments or tubular elements.

Background of the invention

Under normal circumstances, there are thermoregulatory mechanisms in the healthy human body to keep the body at a constant temperature of about 37 ° C (98.6 ° F), a condition sometimes called normothermia. To maintain normothermia, thermoregulatory mechanisms act so that the heat that is lost to the environment is replaced by the same amount of heat generated by metabolic activity in the body. For various reasons, a person can develop a body temperature that is below normal, a condition called hypothermia.

Accidental hypothermia can occur when heat loss to the environment exceeds the body's ability to produce heat internally, or when a person's thermoregulatory capacity has been reduced due to injury, illness, or anesthesia. Accidental hypothermia is generally a dangerous condition that can have serious medical consequences. For example, hypothermia can interfere with the heart's ability to pump blood or the blood's ability to clot normally. Hypothermia can also interfere with various temperature-sensitive enzymatic reactions in the body, with the resulting metabolic and biochemical consequences, and has sometimes been associated with a poor immune response and an increased incidence of infections.

Simple methods of treating hypothermia have been known since ancient times. Such methods include wrapping the patient in blankets, administering warm fluids orally, and immersing the patient in a hot water bath. If the hypothermia is not too severe, these methods can be effective. However, wrapping a patient in a blanket depends on the patient's own body's ability to generate heat to rewarm the body. Administering warm fluids by mouth depends on the patient's ability to swallow, and is limited by the temperature of the liquid consumed and by the amount of fluid that can be administered in a limited period of time. Immersing the patient in hot water is often impractical, particularly if the patient is simultaneously undergoing surgery or some other medical procedure.

More recently, hypothermia can be treated by applying a heating blanket that applies heat to the patient's skin. However, applying heat to the patient's skin may be ineffective in delivering heat to the interior of the patient's body. Heat applied to the skin has to be transmitted through the skin by conduction or radiation, which can be slow and ineffective, especially if the patient has a significant layer of fat between the thermal blanket and the inside of the body.

Paradoxically, applying heat to the skin of a hypothermic patient, either by immersion in hot water or by applying a heating blanket, can actually aggravate the problem and can induce shock. The body has certain thermoregulatory responses that tend to cool that function to conserve heat within the body, especially vasoconstriction and arteriovenous shunts (AV shunts). Vasoconstriction occurs when capillaries and other blood vessels in the skin and extremities contract so that most of the blood pumped by the heart circulates inside the body instead of through the skin and extremities. Similarly, in AV shunt, there are blood shunts that occur naturally between some arteries that supply blood to capillary beds in the skin and to the extremities and to veins that return blood from those capillary beds. When the blood cools, these shunts can open, allowing the blood to bypass those capillary beds completely. Thus, when the body cools, the tissues of the extremities, and, in particular, those of the surface, have little blood flowing into them and can become quite cold compared to the temperature inside the body.

When heat is applied to the skin of a hypothermic patient, temperature sensors in the skin can cause the vasoconstriction to reverse and the AV shunts to close. When this happens, the blood from within flows into the extremely cold tissue on the body's surface and extremities, and as a result, the blood loses heat to those tissues, often much more than the amount of heat being added through the body. surface heating. The result is that the temperature inside the victim's body can plummet and the patient can even go into shock.

Partly in response to deficiencies in surface heat application, methods have been developed to deliver heat to a patient's body by internal means. A patient being administered gases for respiration, for example a patient under anesthesia, may receive heated breathing gases. This method can be effective, but it is limited to the amount of heat that can be delivered without damaging the lungs. Similarly, a patient receiving intravenous fluids may receive warmed fluids, or a hot fluid bolus may be administered intravenously. This can be effective in the case of mild hypothermia, but the temperature of the intravenous fluid is limited by the temperature that will be destructive to the blood, which is generally believed to be between about 41<sup>°</sup>C-49<sup>°</sup>C and by the amount of fluid that is acceptable to administer to a particular patient.

A more invasive method can be used to bring heat to a patient's blood, particularly in the case of cardiac surgery. Blood is drawn from the patient, circulated through a cardiopulmonary bypass system (CPB), and reintroduced into the patient. The blood can be heated or cooled before being reintroduced into the patient. This method of

ES 2 278 624 T3

CPB is both fast and effective in supplying or extracting heat from a patient's blood, but it has the disadvantage of involving a very invasive medical procedure that requires the use of complex instruments, highly specialized technical equipment and usually only it is available in a surgical setting. It also involves the mechanical pumping of blood, which is generally very destructive of blood tissue, leading to cytotoxic and thrombolytic problems associated with drawing blood from the body, mechanical pumping of blood, and channeling of blood through various machines and conduits.

Means of supplying heat into the body have been suggested that do not involve pumping blood with an external mechanical pump. For example, in U.S. Patent No. 5,486,208, issued to Ginsburg, the entire approach of which is incorporated herein by reference, a method of treating hypothermia or hyperthermia by means of an exchange catheter was described. thermic placed in the bloodstream of a patient. That patent presents a method to treat or induce hypothermia by inserting a catheter for heat exchange equipped with a heat exchange zone that includes a balloon with heat exchange fins that is introduced into the bloodstream of a patient and to circulate a fluid of heat exchange by the balloon while the balloon is in contact with the blood to contribute or extract heat from the bloodstream. (As used herein, a balloon is a structure that is easily inflatable under pressure and that folds under vacuum.) Under certain conditions, heat is generated within the body or the environment contributes heat in an amount that exceeds the body's capacity. to dissipate heat, and then the person develops a condition of abnormally high body temperature, a condition called hyperthermia. Examples of this condition can be the consequence of exposure to a hot and humid environment or environment, to excessive efforts, or to exposure to the sun while the body's thermoregulatory mechanisms are disabled by drugs or disease. Additionally, often as a result of injury or illness, a person can set a set point temperature that is above normal body temperature at around 37 ° C. The set value temperature is the temperature that the body's thermoregulatory mechanisms act to maintain. Under normal circumstances, this is about 37 ° C, but in other cases, such as fever, the body may set a different temperature than the set value and act to maintain that temperature.

Like hypothermia, hyperthermia is a serious condition that can sometimes be fatal. In particular, hyperthermia has been found to be neurodestructive, both by itself and in conjunction with other health problems, such as stroke, where an above-normal body temperature in conjunction with a stroke or traumatic brain injury is It has been shown to result in a far worse outcome.

As with hypothermia, there are trade-offs to simple methods of treating the condition, such as cold baths and cooling blankets, and there are also more effective but complex and invasive means, such as refrigerated respiratory gases and chilled blood during CPB. . These, however, are subject to the limitations and complications described above in connection with hypothermia. In addition, thermoregulatory responses such as vasoconstriction, AV shunting, and shivering may act directly to combat the attempt to cool the patient and thus defeat the effort to treat hyperthermia. This is especially the case with fever, where the body can establish a setpoint temperature higher than normothermia and actively resist efforts to reduce the febrile body temperature to normothermia.

Although both hypothermia and hyperthermia can be harmful and require treatment in some cases, in other cases hyperthermia and especially hypothermia can be therapeutic or otherwise be advantageous, and therefore can be induced intentionally. For example, periods of cardiac arrest in myocardial infarction and cardiac surgery can lead to brain damage or nerve damage of another nature. Hypothermia is recognized in the medical community as an accepted neuroprotectant and therefore the patient is often kept in a state of induced hypothermia during cardiovascular surgery. Similarly, hypothermia is sometimes induced as a neuroprotectant during neurosurgery.

It is sometimes desirable to induce whole body or regional hypothermia for the purpose of treating or minimizing the adverse effects of certain neurological diseases or disorders, such as head trauma, spinal trauma, or hemorrhagic or ischemic stroke. In addition, it is sometimes desirable to induce a regional or whole body hypothermia in order to facilitate or minimize the adverse effects of certain surgical or interventional procedures such as open heart surgery, aneurysm repair surgeries, endovascular aneurysm repair procedures. , spinal surgeries, or other surgeries in which blood flow to the brain, spinal cord, or vital organs may be interrupted or compromised. Hypothermia has also been found to be advantageous in protecting cardiac muscle tissue after myocardial infarction (myocardial infarct, MI).

Neural tissue, such as the brain or spinal cord, is particularly subject to injury caused by vascular disease processes, including ischemic or hemorrhagic stroke, lack of blood to any area, including cardiac arrest, hemorrhage or obstruction intracerebral or intracranial and head trauma, among others. In each of these cases, brain tissue damage can occur due to cerebral ischemia, increased intracranial pressure, edema, or other conditions, often leading to loss of brain function and permanent neurological deficits. Although the mechanism of neuroprotection is not fully understood, it is believed that lowering brain temperature achieves neuroprotection through several mechanisms, including attenuation of any elevation in neurotransmitter (eg, glutamate) that occurs after an episode. ischemic, a reduction in brain metabolic rate, moderation of intracellular calcium transport / metabolism, the prevention of ischemia-induced inhibitions of protein synthesis and / or a reduction

ES 2 278 624 T3 of free radical formation, as well as other enzymatic cascades and even genetic responses. Thus, intentionally induced hypothermia may partly prevent injury to the brain or other neurological tissues during surgery or as a result of stroke, intracerebral hemorrhage, and trauma.

Intentionally inducing hypothermia has generally been attempted either by surface cooling or by bypass pumping. Surface cooling has generally been shown to be unacceptably slow, since the body heat to be reduced must be transmitted from the interior to the surface, and has sometimes been a total failure, since the body's thermoregulatory mechanisms are at work to prevent surface cooling from reducing internal body temperature. For example, vasoconstriction and AV shunt can prevent heat generated inside from being transmitted to the surface through the blood. Therefore, superficial cooling may only cool the skin and superficial tissue and may not reduce the temperature inside the patient to induce a hypothermic state.

Another thermoregulatory mechanism that can thwart attempts to reduce internal temperature by surface cooling is shivering. There are numerous thermal sensors on the body surface, and they can cause the body to start shivering. The shivering leads to the generation of a significant amount of metabolic heat, which becomes five times the norm, and, with the blood reaching the surface of the body very limited, the cooling blanket can only reduce the temperature of the patient very slowly, in the event that it does. If the patient has a fever and therefore a high set point temperature and thus shivers at a temperature that is above normothermia, it has been found that cooling blankets are often unable to reduce the patient's temperature or even to normothermia.

Furthermore, since heat transfer from the surface to the interior of a patient by applying cooling blankets is slow and inefficient, controlling the temperature of the interior of the patient by surface cooling is very difficult, if not impossible. The temperature of the patient tends to go beyond the desired reduced temperature, a potentially catastrophic problem when the temperature inside a patient is reduced, especially to moderate or severe levels. Rapid adaptation of the internal temperature by surface cooling is difficult or even impossible, particularly if precise control is required.

As with the use of CPB machinery to heat blood removed from the body and back into the body, cooling bypass can be quick and control can be relatively precise, especially if a large volume of blood is being pumped. through the system very quickly. However, as previously noted, this method is complex, expensive, invasive, and generally blood-damaging, particularly if followed for a significant time.

In addition to intentionally induced hypothermia or hyperthermia, it is sometimes desirable to control a patient's temperature to keep the patient at normothermia, that is, at the normal body temperature of approximately 37 ° C. For example, in a patient undergoing general anesthesia, normal body thermoregulatory centers and mechanisms may not be working perfectly, and the anesthetist may wish to control the patient's body temperature by directly supplying or withdrawing heat. Similarly, a patient may lose an extraordinary amount of heat to the environment, for example during major surgery, and the patient's body may not be able to generate enough heat unaided to compensate for the lost heat. This is especially the case where, as a result of the anesthesia used during surgery, the patient's normal thermoregulatory response is reduced or eliminated. A device and method for controlling body temperature by supplying or withdrawing heat to maintain normothermia would be desirable.

In addition, a patient may suffer illness or trauma, or certain substances have been introduced into the body that cause a temperature with a high set value, leading to fever, as occurs in the case of infection or inflammation. In the absence of help, the body can then maintain a temperature above 37 ° C, and surface cooling may be ineffective in combating the body's thermoregulatory activity and reestablishing normothermia. Where the presence of fever has been found to correlate with a very negative outcome, for example in a stroke, it may be highly desirable to maintain normothermia.

The mammalian body generally functions extremely efficiently in normothermia. Therefore, maintaining hypothermia in one portion of the body, such as the brain or heart, while maintaining the temperature of the rest of the body at normothermia can allow protection of the target tissue, for example neuroprotection of the brain or protection of the myocardium, while allowing the rest of the body to function in normothermia. Document US 5,486,208 presents an apparatus for controlling the body temperature of a patient, as described in the preamble of claim 1.

For the foregoing reasons, there is a need for a means of supplying heat to a patient's body, or extracting heat from it, in an effective and efficient manner, while avoiding the inadequacies of surface heat exchange and the dangers of the methods. of CPB, which require the pumping of the blood drawn from the patient's body, the heating or cooling of the blood, and its subsequent return to the patient. There is a need for a means of rapidly, efficiently and in a controlled manner exchanging heat with the blood of a patient so that the temperature of the patient or target tissue within the patient can be altered or maintained at a certain desired temperature. Summary of the invention

The present invention features a heat exchange catheter provided with a heat exchange portion comprising multiple heat exchange elements (for example, distinct elements such as tubes or filaments).

Additionally, in accordance with the invention, a catheter for heat exchange of the invention may comprise a flexible body or shaft

ES 2 278 624 T3 tubular of the catheter provided with a proximal end and a distal end, the distal end of said tubular shaft of the catheter being adapted to be inserted percutaneously into the vasculature or body cavity of a mammalian patient. A heat exchange region, consisting of a plurality of fluid impervious elements for heat exchange, is provided on the tubular shaft of the catheter, each of which has opposite length and ends, each element being joined by at least one end to the tubular shaft of the catheter. When inserted into a blood vessel or other body cavity, body fluid can surround each heat exchange element. The tubular shaft of the catheter preferably includes a circulation path or conduit, and each heat exchange element is preferably joined at both ends to the tubular shaft and incorporates a circulation path or conduit that is in fluid communication with the circulation path or conduit of the tubular shaft of the catheter. In this way, the heat exchange fluid can circulate within or through the individual heat exchange elements while they are circumferentially surrounded by the body fluid. Alternatively, the individual heat exchange elements may incorporate dead-end filaments, and may therefore be attached to the tubular shaft of the catheter only at one end.

Furthermore, according to some embodiments of the invention, the heat exchange zone may be less than half the length of the tubular shaft of the catheter and may be located at or near the distal end thereof. In such embodiments, an insulating zone may be formed on the tubular shaft of the catheter proximal to the heat exchange zone to reduce unwanted heat transfer to and from the proximal portion of the tubular shaft of the catheter.

Furthermore, in accordance with the present invention, there is presented a system for heat exchange with a body fluid, the system including a) a liquid heat exchange medium and b) a catheter for heat exchange provided with a plurality of elongated differentiated elements of heat exchange. The catheter includes a tubular shaft provided with a proximal end and a distal end, the distal end being adapted to be inserted percutaneously into a body cavity, the tubular shaft having a circulation path inside it for circulation through it from the heat exchange medium. The differentiated heat exchange elements are attached to the catheter in such a way that when the catheter is inserted into the body cavity, there is body fluid surrounding each element.

The system may further include a sensor or sensors attached to, or inserted into, the patient to provide feedback relative to the condition of the patient, for example the temperature of the patient. It is desirable that the sensors are in communication with a controller that controls the catheter for heat exchange based on feedback from the sensors.

A method for exchanging heat with a body fluid of a mammal is further described. The method includes the steps of a) providing a catheter that has in its interior a pathway for the circulatory flow of a fluid and a heat exchange region thereon, said heat exchange region including heat exchange elements that are attached to the shaft. tubular catheter in the heat exchange region, b) inserting the catheter into a body cavity and in contact with a body fluid, the heat exchange elements being thus surrounded by the body fluid and c) causing a heat exchange medium to flow through the circulatory flow path of the catheter so that the medium exchanges heat with a body fluid through the heat exchange elements. Each of the heat exchange elements may be hollow, and step C of the method may include causing the heat exchange fluid to flow through the hollow heat exchange elements.

It is an object of this invention to present an effective means of supplying heat to a patient suffering from hypothermia.

It is a further object of this invention to present an effective means of extracting heat from the blood stream of a patient suffering from hyperthermia.

It is a further object of this invention to present an effective means of supplying heat to a patient, or of extracting it, to induce normothermia.

It is a further object of this invention to present an effective means of maintaining normothermia.

It is a further object of this invention to present an effective means of cooling a patient to a desired temperature and maintaining that temperature in a controlled manner.

It is a further object of this invention to present a cooling catheter having an advantageous configuration.

It is a further object of this invention to cool an area of interest to a patient.

It is a further object of this invention to maintain a patient at a desired temperature.

It is a further object of this invention to present a heat exchange catheter that is configured to efficiently exchange heat with the blood of a patient while allowing continued flow of blood past the catheter with a minimum of restriction to that blood flow.

It is a further object of this invention to present a heat exchange catheter provided with multiple balloons for heat exchange.

It is a further object of this invention to present a heat exchange catheter provided with a heat exchange portion comprising multiple filaments.

It is a further object of this invention to present a catheter for heat exchange provided with an insulated tubular shaft.

An effective method of controlling the temperature of a body fluid is further described.

An effective method of heating a body fluid is further presented.

In addition, an effective method of cooling a body fluid is presented.

An effective method to induce hypothermia is further described.

Brief description of the drawings

Figure 1 is a perspective view of a patient undergoing treatment using a system in accordance with the present invention;

Figure 2 is a cross section of a patient's vessel showing an embodiment of a catheter for heat exchange of the present invention inserted therein;

ES 2 278 624 T3 Figure 3 is an elevation of a model embodiment of a catheter for heat exchange of the present invention equipped with multiple differentiated hollow elements for the flow of heat transfer medium through them in a distal portion of the catheter;

Figure 4A is a cross section of a proximal end of the catheter of Figure 3 taken along line 4A-4A;

Figure 4B is a cross-section similar to Figure 4A of an alternative catheter;

Figure 5A is a cross section of the distal heat transfer portion of the catheter of Figure 3, taken along line 5-5, and showing six heat exchange elements.

Figure 5B is a cross section, similar to that of Figure 5A, of an alternative heat transfer portion of a catheter provided with three heat exchange elements.

Figure 6 is a longitudinal section through the distal heat transfer portion of the catheter of Figure 3 taken along line 6-6 of Figure 5A;

Figure 7 is a longitudinal section through an alternative embodiment of a catheter for heat exchange of the present invention provided with multiple differentiated hollow elements so that a heat transfer medium arranged along the length of the element flows through them. the entire length of the catheter;

Figure 8 is an elevation of an alternative embodiment of a heat exchange catheter of the present invention provided with an insulating proximal region and a distal heat exchange region;

Figure 8A is a cross section of an insulating region of the catheter of Figure 8, taken along line 8A-8A, with spacers interposed between a central tubular fluid supply shaft and an outer balloon;

Figure 8B is a cross section similar to Figure 8A of an alternative configuration of an insulating region with a plurality of inflatable spacers between the central tubular fluid supply shaft and an outer jacket;

Figure 9 is an elevation of a distal portion of an alternative embodiment of a heat exchange catheter of the present invention provided with a plurality of flexible heat exchange elements connected at one end of the catheter;

Figure 9A is a cross section of a heat exchange element of the catheter of Figure 9 provided inside it with a path for the circulation of a fluid made along the line 9A-9A;

Figure 10A is a detailed view of a portion of a differential heat exchange element of the present invention provided with a helical fin thereon for improved heat transfer;

Figure 10B is a detailed view of a portion of a differential heat exchange element of the present invention provided with circumferential fins thereon for improved heat transfer;

Figure 11 is an elevation of a distal portion of an alternative heat exchange catheter of the present invention provided with a plurality of differentiated undulating elements for the heat transfer medium to flow therethrough;

Figure 12 is a cross section through a hollow heat exchange element of the present invention provided with a non-circular configuration and increased surface area for heat transfer;

Figure 13 is a cross section through an alternative heat exchange catheter of the present invention provided with a plurality of flexible heat exchange elements connected at one end of the catheter adapted to flow a fluid therethrough;

Figure 14 is a cross section through one of the flexible elements for heat exchange shown in Figure 13, taken along line 14-14;

Figure 15 is a side view of a heat exchange catheter of the invention provided with coaxial heat exchange elements;

Figure 16 is a cross section of the proximal manifold for the heat exchange catheter of Figure 15;

Figure 17 is an enlarged cross section of the distal end of one of the coaxial heat exchange elements;

Figure 18 is a cross section of the proximal portion of the tubular shaft of the heat exchange catheter taken along line 18-18 of Figure 15;

Figure 19 is a horizontal section of the front plate of the proximal distributor of the heat exchange catheter taken along line 1919 of Figure 16;

Figure 20 is a horizontal section of a divider plate of the proximal distributor of the heat exchange catheter shown at 20-20 of Figure 16;

Figure 21 is a side view of a heat exchange catheter of the invention provided with single circuit heat exchange elements;

Figure 22 is a cross section of the proximal distributor of the heat exchange catheter of Figure 21;

Figure 23 is an enlarged cross section of the distal end of a single circuit heat exchange element;

Figure 24 is a cross section of the proximal portion of the tubular shaft of the heat exchange catheter taken along line 24-24 of Figure 21;

Figure 25 is a horizontal section of the front plate of the proximal distributor of the heat exchange catheter taken along line 2525 of Figure 22; and Figure 26 is a horizontal section of the front plate of the proximal distributor of the single circuit heat exchange catheter taken along line 26-26 of Figure 22.

Description of preferred embodiments

The present invention features an improved heat exchange catheter that provides increased surface area for heat transfer with the respective body fluid without increasing the overall size of the catheter cross section. Although the present invention is intended to be used primarily in the bloodstream to regulate the temperature of the patient's blood, the per11

Those skilled in the art fully understand that various additional applications of the catheter of the present invention are possible. Indeed, the present invention may have applications beyond controlling the temperature of an internal body fluid, and the claims should not be limited in that regard.

In a preferred application, one or more of the catheters of the present invention are placed within the vasculature of the patient to exchange heat with the blood to regulate the overall body temperature, or to regulate the temperature of the localized region of the patient's body. The catheter of the present invention may be, for example, suitable for exchanging heat with the arterial blood flowing to the brain to cool the brain, and thus may prevent injury to brain tissue that could otherwise result from stroke or other injury. , or to cool the venous blood flowing to the heart to cool the myocardium to prevent tissue injury that could otherwise occur after MI or other similar event.

The heat exchange catheters presented herein can be used in a suitable heat exchange system to regulate the temperature of a patient or a region of the patient's body. An example of such a heat exchange catheter system 20 using any of the catheters presented herein is shown in Figure 1. System 20 may include a catheter control unit 22 and a heat exchange catheter 24 formed with at least one heat transfer section 44. The heat transfer section or sections are located in that portion of catheter 24, as follows. illustrated by section 26, which is inserted into the patient. This insertion portion is less than the full length of the catheter and extends from the location in the catheter, immediately within the patient, when the catheter is fully inserted, to the distal end of the catheter. Catheter control unit 22 may include a fluid pump 28 to circulate a fluid or heat exchange medium within catheter 24, and a heat exchanger component to heat and / or cool circulating fluids within the transfer system. thermal 20. A fluid reservoir or bag 30 may be connected to control unit 22 to provide a source of heat transfer fluid, such as a blood substitute saline solution or other biocompatible fluid. A circulatory flow channel for heat exchange within the catheter may be connected respectively to inlet 32 and outlet 34 of pump 28 for circulation of heat transfer fluid to cool fluid flow within a chosen region of the body. A similar system can be implemented for heating selected regions of the body simultaneously or independently of the cooling component of the system.

The control unit 22 may further receive data from a variety of sensors which may be, for example, solid state thermocouples to provide feedback from the catheter and various sensors to provide information regarding the patient's temperature representing the internal temperature or the temperature of specific portions or organs of the body. For example, the sensors may include a brain or cranial region temperature probe 36, a rectal temperature probe 38, an ear temperature probe 40, an esophageal temperature probe (not shown), an esophageal temperature probe (not shown) bladder temperature, and the like.

Based on the sensed temperatures and conditions, the control unit 22 may responsively direct the heating or cooling of the catheter. The control unit 22 can activate a heat exchanger at a first detected temperature, and can also deactivate the heat exchanger at a second detected temperature, which can be higher or lower than the first detected temperature or any other predefined temperature. . Of course, the control unit 22 can independently heat or cool particular heat transfer sections to achieve desired or predefined temperatures in body regions. Similarly, controller 22 can activate more than one heat exchanger to control the temperature in particular regions of the patient's body. The controller could also activate or deactivate other devices, for example external heating blankets or the like, in response to sensed temperatures. The regulation exerted on the catheters for heat transfer and other devices can be a simple on-off control, or it can be a significantly more sophisticated control model that includes regulating the degree of heating or cooling, increasing rates of heating or cooling, proportional control as the temperature of the patient or the heat exchange region approaches a desired temperature, or the like.

Catheter control unit 22 may further include a thermoelectric cooler and heater (and associated flow conduits) that are selectively activated to perform both heating and cooling functions with the same, or different, means for heat transfer within the system. of closed-circuit catheters. For example, a cold solution may be circulated through a first heat transfer section 42 located in the insertion portion 26 of at least one heat regulating catheter 24 in an area adjacent to the head, or, alternatively, within the carotid artery or other blood vessel leading to the brain. Cranial temperature can be monitored locally with thermal sensors 36 positioned on a relatively close outer surface of the patient or within specific body regions. Through another heat transfer section 44 of the catheter 24 located also in the insertion portion 26, a hot solution can circulate inside a collapsible balloon or, if not, heat can be supplied to other areas of the body by means of heating elements or other mechanisms described accordingly. with other aspects of the invention. Although the heat exchange catheter 24 can provide regional hypothermia to the brain area for neuroprotective benefits, other parts of the body can be kept relatively warm so that adverse side effects such as discomfort, shivering, can be avoided or minimized. blood coagulopathies, immune deficiencies and the like. Warming of the body generally below the neck can further be achieved by insulating or wrapping the lower body in an electric pad or blanket 46, while the cranial region by en

ES 2 278 624 T3 top of the neck is fresh. Of course, it should be understood that multiple heat exchange sections of catheter 24 can be modified to allow cooling or heating of the entire body to affect internal body temperature.

Figure 2 illustrates a particular heat exchange catheter 50 of the present invention inserted into a body cavity, in this case a BV blood vessel. Blood flow F is indicated by arrows pointing to the right. The heat exchange catheter 50 includes an elongated tubular shaft 52 adapted to extend through a puncture wound 54 into the blood vessel BV. Catheter 50 has a proximal end that remains outside the body and a distal end that is inserted into the body cavity.

A heat exchange region 56 is provided along the distal portion of catheter 50 that is introduced into the bloodstream. Heat exchange region 56 corresponds to either of heat exchange regions 42 or 44 described above with respect to Figure 1. The illustrated embodiment is shown in more detail in Figures 3-6, and includes a plurality of heat exchange elements 58 attached to the tubular shaft of catheter 52 that provide, as will be described, improved heat exchange with blood. Any of the other embodiments presented in the present application may replace the one shown in heat exchange region 56.

Referring to Figure 3, the heat exchange catheter 50 consists of the aforementioned elongated tubular shaft 52 provided with a heat exchange region 56 at a distal end and has a plurality of ports 60 at the proximal end. In particular, catheter 50 includes a fluid inlet port 60a, a fluid outlet port 60b, and a guidewire insertion port 60c.

Figure 4A illustrates a cross section of elongated tubular shaft 52 taken along line 4A-4A of Figure 3, in which three conduits are presented within the tubular shaft. A conduit 62 for the wire guide is generally located between two conduits 64 and 66 for circulation of the heat exchange fluid. One flow conduit 64 is in fluid communication with fluid inlet port 60a, and the other flow conduit 66 is in fluid communication with fluid outlet port 60b. However, it can easily be determined that if flow in the opposite direction is desired, for example to achieve counter-current flow with blood, as described below, either conduit can function as an inflow conduit, making the other outflow conduit conduit. The direction of the flow can thus be easily and satisfactorily reversed.

Figure 4B illustrates an alternative cross section of elongated tubular shaft 52 in which a centrally located conduit 62 'for the wire guide is positioned between two circulation conduits 64' and 66 'for heat transfer fluid.

It is desirable that the transverse configuration of tubular shaft 52 extends from a junction with a hub 68 to the distal end 69 of the catheter. Alternatively, the end distal portion may consist of just the wire guide conduit or an extension thereof. The view of the

Figure 3 is somewhat simplified, as indicated by the break lines, and the catheter 50 in this exemplary embodiment can be anywhere between 60 and 150 cm in length.

The heat exchange region 56 begins at an outlet manifold 70 and ends at an inlet manifold distally from the previous one. Several of the aforementioned heat exchange elements 58 extend adjacent to, and generally parallel to, tubular shaft 52 between inlet and outlet manifolds 70, 72. Each element 58 is attached by at least one of its ends to the heat exchange region 56 and at least a portion of its length is transversely spaced from the tubular shaft 52 so that when inserted into a fluid body cavity provided with fluid inside , the body fluid circumferentially surrounds each heat exchange element. The term "circumferentially surround" is not intended to imply that the cross section of each heat exchange element 58 is circular, but rather means that, when viewed in cross section, each element is peripherally surrounded by body fluid. . This greatly increases the effective surface area for heat exchange of catheter 50 and facilitates heat exchange with body fluid.

As seen in the cross section of Figure 5A, there are six such heat exchange elements 58 evenly distributed around the circumference of the tubular shaft of catheter 52. As will be appreciated from the following discussion, improved heat exchange can be achieved using catheter 50 with nothing more than two heat exchange elements 58. For example, Figure 5B illustrates an alternative embodiment with three heat exchange elements 58 '. As illustrated, heat exchange elements 58 are uniformly distributed around the circumference of tubular shaft 52, but other configurations are possible, such as that shown in Figure 8.

The heat exchange catheter 50 of the present invention provides within it a circular fluid flow path, as can be seen perfectly in Figure 6. In the illustrated embodiment, the circulatory flow of the fluid extends through the elements. 58 heat exchange. In Figure 6, the upper conduit 64 acts as the inflow conduit for the heat exchange medium. The lower conduit 66 acts as the outflow conduit for the heat exchange medium. However, if it is desired that the flow of the heat transfer fluid in the heat exchange elements be in the opposite direction to that illustrated here, it can be easily achieved by reversing the function of these two conduits.

The pathway of circulatory flow in heat exchange region 56 of catheter 50 is illustrated in Figure 6 by flow arrows 74 and 75. Specifically, the exchange medium travels distally through inflow conduit 64 until it reaches a port 76 that is in fluid communication with an interior space 78 defined within the inlet manifold 72. It is desirable that each of the heat exchange elements 58 be formed as a hollow tube having an inflow orifice 80 in fluid communication with the interior space 78. Similarly, each heat exchange element 588

ES 2 278 624 T3 mico has an outflow orifice 82 that is in fluid communication with an interior space 84 defined within outlet manifold 70. Outflow conduit 66 has a port 86 that receives the exiting heat exchange medium. outflow ports 82. A plug member 88 provided in the outflow conduit 66 prevents the heat exchange medium from following distally past the outlet manifold 70, while the plug members 89 close the distal ends of conduits 64 and 66. To reiterate the circulatory flow path, heat exchange medium travels distally (arrow 74) through inflow conduit 64 to exit port 76, enters space 78 within inlet distributor 72, travels into space to enter through the holes 80 the inflow of each of the heat exchange elements 58, travels proximally (arrows 75) through the heat exchange elements, flows from outflow ports 82 into space 84 formed within outlet manifold 70, and enters outflow conduit 66 through port 86, which returns media to the proximal end of catheter 50. Again, the flow of the heat transfer fluid through the heat exchange elements 58 could be in the distal or proximal direction and, depending on the catheter insertion technique, the flow could be concurrent or divergent with respect to the direction of the Blood flow.

The inlet and outlet manifolds 70, 72 can be formed by a variety of constructions, showing a thin-walled flared sleeve. Inlet and outlet manifolds 70, 72 are profiled at one end to meet the exterior of tubular shaft 52 and are sealed thereto. At the opposite end, the open area within each manifold receives the ends of the heat exchange elements 58, and a silicone resin 90, which may be a suitable adhesive, seals the interior spaces 78 and 84 from outside the pathway. of circulatory flow. The heat exchange elements 58 are thus sealed between the respective distributors 70, 72 and the silicone resin in a fluid-tight manner. Naturally, other constructions can be used for the flare sleeve, such as a molded polymer or a clear plastic type material for wrapping, and other constructions like a gasket can be used for the silicone resin.

The heat exchange elements 58 are illustrated in their state slightly angled outward from the tubular shaft of catheter 52. This arrangement ensures that the elements 58 are surrounded by fluid during use, as seen in Figure 2, to greatly magnify the heat transfer capacity for a given rate of fluid flow. That is, the heat exchange medium splits at the distal end of the catheter and flows proximally through a plurality of parallel pathways, each of which passes through heat exchange elements 58, each provided with a continuous outer surface. This arrangement is best illustrated in Figures 5A and 5B. In addition, part of the heat exchange takes place between the inflow conduit 64 and external body fluid through the wall of the tubular shaft 52.

One means of ensuring spacing between heat exchange elements 58 and tubular shaft 52 is to have a spring between them, such as that shown at 92 in Figure 6. It is desirable that a spring 92 be connected to a radially inner portion. of each heat exchange element 58 and which is in the form of a cantilever oriented towards the tubular axis 52 and in contact with it. During insertion of catheter 50, external forces can cause heat exchange elements 58 to be pushed inward, compressing spring 92, which slides against tubular shaft 52. Upon placement of the catheter in the appropriate body cavity, spring 92 expands to move heat exchange elements 58 radially outward to the optimum heat exchange position. It is advantageous that the springs 92 have a relatively low profile in the blood flow path and thus minimize any obstruction to the flow of blood.

Another construction that would ensure, while in use, the spacing between heat exchange elements 58 and tubular shaft 52 is to provide thin-walled inflatable tubes as heat exchange elements. The elements are slightly longer than the distance between the inlet and outlet manifolds, 70, 72. When elements 58 are folded, for example upon insertion into the patient, they will do so by laying flat against the tubular shaft to present a low profile. When inflated, for example by a heat exchange fluid flowing under pressure while in use, they will tilt outward away from the tubular shaft. See, for example, Figure 3 and Figure 8. Alternatively, the distance between the inlet and outlet distributors 70, 72 may be variable by means of a line (not shown) or other similar device acting on the tubular shaft 52. For example, the tubular shaft 52 may be constructed in sections of decreasing diameter that are inserted into each other, or can be bent, so that the distance between the input and output distributors 70, 72 can be shortened with the actuation of the line. In this way, the elements 58 initially lie flat against the elongated tubular shaft 52, but are then caused to tilt outward away from the shortened tubular shaft.

Another advantage of having a plurality of flexible heat exchange elements, such as those shown at 58, is that the cross-sectional profile of heat exchange region 56 easily conforms to tortuous body cavities. That is, as best seen in Figure 5A, the circumferential gaps present between each of the individual heat exchange elements 58 allow them to move radially and circumferentially so that they can be more crowded on one side or the other. This ability to change position greatly improves the ability to position heat exchange region 56 within narrow or tortuous body cavities and in activating heat exchange fluid flow to expand heat exchange elements without undue restriction of heat. blood flow around the heat exchange region. It has been found that generally adequate flow can be maintained in the blood vessel if the heat exchange elements obstruct 50% or less of the cross-sectional area of the vessel.

Figure 7 shows an alternative embodiment of a catheter for heat exchange

ES 2 278 624 T3

100 of the present invention. Catheter 100 is similar to catheter 50 previously described, in that the circulation path of the heat exchange medium is inside it and a plurality of elongated heat exchange elements 102, differentiated from a tubular shaft of catheter 104, form a portion of the traffic lane. In the exemplary embodiment of Figure 7, however, the heat exchange region 106 extends along the entire length of the tubular shaft of the catheter 104.

It is preferable that each of the heat exchange elements 102 is formed as a hollow elongated filament. The heat exchange catheter 100 includes in its interior a fluid circulation path that consists of an inner conduit or conduit 108 formed within the inner tubular shaft 104, of a space 110 formed within a distributor 112 that is at the distal end of the catheter, and a hollow conduit of heat exchange elements 102 is in fluid communication with that space 110. The proximal end of the inner tubular shaft 104 fits into an inlet fitting 114 provided with an inner chamber 116 that communicates with the conduit 108. The inner tubular shaft 104 extends through a chamber 118 formed in an outlet fitting 120 , and the proximal ends of heat exchange elements 102 are sealed in fluid communication with chamber 118 using a silicone resin 122. In this way, fluid entering chamber 116, as indicated by arrow 124, is directed into conduit 108 and travels distally through catheter 100, as indicated by arrows 126. At distal distributor 112 , the fluid is deflected 180 degrees into the hollow passage of the heat exchange elements 102. Once again, the silicone resin 128 is used to seal the distal ends of the elements 102 within the space 110. Fluid travels proximally through elements 102, as indicated by arrows 130, and exits the heat exchange elements to enter chamber 118 to be removed from the chamber as indicated by arrow 132.

The advantage of having a heat exchange region 106 along the entire length of catheter 100 is the ability for greater heat exchange with body fluid. In addition, catheter 100, provided with a heat exchange region 106 along one hundred percent of its length, can more effectively provide heating or cooling to the entire body. Furthermore, in the previously described catheter, some heat could be transferred to or from the body fluid through the proximal portion of the catheter that is not part of the heat exchange region. In the exemplary embodiment of Figure 7, on the other hand, the entire catheter is designed to exchange heat with the body fluid.

Figure 8 illustrates a further embodiment of a heat exchange catheter 150 provided with a heat exchange region 152 at its distal portion, and an insulating region 154 at its proximal portion. In the illustrated embodiment, heat exchange region 152 and insulator region 154 are approximately equal in length, both being approximately 50 percent of the total length of catheter 150. In a preferred embodiment, the insulating region 154 is substantially longer than the heat exchange region.

152, and preferably at least 75 percent of the length of catheter 150. It is desirable that the combined length of heat exchange region 152 and an insulating region 154 be approximately equal to the total length of catheter 100. An example Specific is the insulating region that extends approximately 85-90% of the total length of the catheter, and a heat exchange region that extends the remaining 10-15%. Of course, various alternative configurations are contemplated, including intermittent and interspersed insulating and heat exchange regions.

As before, catheter 150 of Figure 8 includes an inlet port 160 for the heat exchange medium and an outlet port 162 for the heat exchange medium. There is a fluid flow path (not shown) within elongated tubular shaft 164. There are a plurality of heat exchange elements 166 parallel but spaced from tubular shaft 164 in heat exchange region 152. Preferably, heat exchange elements 166 are hollow filaments that form separate parts of the fluid flow path within catheter 150. To this end, distal manifold 168 receives the distal ends of heat exchange elements 166, and manifold Proximal 170 receives the proximal ends. Distributors 168, 170 define spaces within their interior for fluid flow, a space within distal distributor 168 being in communication with inlet port 160, and a space within proximal distributor 170 being in communication with outlet port 162 . In this manner, a liquid heat exchange medium flows into port 160 and to the distal end of catheter 150 before returning to exit port 162 through hollow heat exchange elements 166.

The insulating region 154 includes an insulating element 172 positioned longitudinally around the tubular shaft 164. The insulating element 172 can be of a variety of constructions, including a solid jacket or a fluid filled balloon. In a preferred embodiment, the insulating element 172 consists of an inflatable balloon provided with an interior space in communication with an inflation port 173. A suitable insulating fluid, such as nitrogen gas or carbon dioxide gas, inflates the balloon 172 away from the side of the tubular shaft 164. In this way, even though the entire length of the tubular shaft 164 is immersed in a body fluid, only the heat exchange region 152 efficiently transfers heat to and from body fluid.

As seen in Figure 8A, tubular shaft 164 may be centered within insulator 172 and kept separate therefrom, for example by collapsible spacers 175, to prevent the tubular shaft from resting against the side of the inflated and comprising insulating member. the insulating capacity of the insulating element. The spacers 175 can be relatively thin and flexible, such that when the insulating element is folded for insertion or removal, it does so against the tubular shaft without significantly thickening the overall profile of the catheter.

Alternatively, as shown in Figure 8B, the insulating element could be a thin-walled, multi-conduit balloon with a central conduit into which the tubular shaft 164 is inserted and insulating conduits 179 surrounding the conduit.

ES 2 278 624 T3 central. An insulating jacket 181 can surround the entire insulating region.

The configuration of Figure 8 provided with an insulating region and a heat transfer region can be particularly useful for cooling the blood flowing to the brain to regionally direct the cooling effect of the catheter. The effectiveness of cooling or heating the blood depends in part on the difference between the temperature of the surface of the heat exchange region in contact with the body and the temperature of the blood. This temperature difference is here called AT. Catheter 150 may be inserted, eg, through the femoral artery, passed through the vasculature, eg, the aorta, so that heat exchange region 152 is located in the carotid artery. The heat exchange fluid is circulated through the catheter 150 and remains cool until it reaches the heat exchange region 152 thanks to the insulating region 154, and thus a maximum AT is maintained. Without the insulating region 154, the effectiveness of the heat exchange medium is decreased, and the result can be significantly less cooling of the blood at the desired location, in this case the carotid artery.

In addition, the regional effect of cooling can also be compromised by the exchange of heat with the blood that does not subsequently circulate to the desired region of the body. In the previous example of cooling the brain regionally, the insulating region 154 prevents the cold heat exchange fluid from exchanging heat with the blood within the arterial system in the femoral artery and in the ascending aorta, blood that would circulate through the trunk and legs of the patient. This cooling of the blood that then circulates to other regions of the body can lead to a general cooling of the entire body. Although this general cooling may be desirable in some applications, it may be undesirable in other applications, such as applications in which it is intended to effect regional or localized cooling of the heart or brain. In this sense, such general cooling can lead to discomfort, such as shivering, in the patient, or other negative side effects of hypothermia of the whole body that could be avoided by a regional cooling.

Until now, heat exchange elements have been described as hollow filaments that form a portion of a fluid flow path and that are attached at both ends to the tubular shaft of the catheter. However, the present invention is more general in nature, in that the multiple and different heat exchange elements need not be attached to the tubular shaft at both ends, but may instead be restricted in their mobility along of a portion of their length with respect to the tubular axis so that a free end thereof is allowed to drift freely within the body fluid. It is desirable that the free-floating elements define a blind internal fluid flow path.

In particular, Figure 9 illustrates a heat exchange catheter 180 in accordance with the present invention having an elongated tubular shaft 182 and a plurality of heat exchange elements 184 attached thereto. Heat exchange elements 184 are attached at distal ends to tubular shaft 182 and generally float freely on distal tips 186. These elements 184 are preferably flexible and collapsible to compress against the exterior of tubular shaft 182 to have a low profile during insertion and removal of catheter 180. Additionally, the flexible nature of elements 184 facilitates placement in tortuous passageways, and its passage through them, and the minimization of the restriction to the flow of blood through the blood vessels when they inflate. It should be noted that the elements 184 along any catheter 180 can be of different lengths. Catheter 180 may further include a proximal isolator element 188, which may be a single-conduit or multiple-conduit balloon, as previously described.

Heat exchange elements 184 can be provided in various constructions. Each of the heat exchange elements 184 can provide a flow of fluids therein. The cross-sectional view of Figure 9A illustrates the heat exchange element 184 provided with a fluid inlet path 190 and a parallel fluid outlet path 192. Fluid paths 190, 192 are placed in fluid communication with a main flow path within tubular shaft 182. In this way, heat exchange elements 184 are somewhat similar to elements 58 described above when doing reference to the first embodiment, but they are somewhat freer to float within the body fluid. Furthermore, having the elements 184 joined at one end allows them to migrate more freely around the circumference of the tubular shaft 182 when the catheter 180 is passed through tortuous passageways. Figures 13 and 14 show a further embodiment of this nature.

To further facilitate heat exchange between body fluid and the heat exchange elements described herein, each element may be provided with a flow discontinuity or other discontinuity rib. It is a well-known principle of heat exchange that reducing the laminar boundary layer around an object in a path for fluid flow increases the potential heat transfer between that object and the fluid. Thus, for example, Figure 10A illustrates a tubular heat exchange element 200 provided with a helical rib 202. Other such configurations are possible, including circumferentially oriented ribs 204 in a heat exchange element 206, as seen in Figure 10B.

To further facilitate heat transfer between heat exchange elements and a body fluid, the surface area of those elements can be increased in various ways without significantly altering the overall transverse volume of the catheter. Thus, for example, Figure 11 illustrates a heat exchange region 210 in a catheter of the present invention in which a plurality of undulating heat exchange elements 212 extend from a distal manifold 214 to a proximal manifold 216 with which it is provided. a tubular shaft 218. In other words, the elements 212 extend along a non-linear path, with at least one point of inflection. This configuration provides greater surface area for each heat exchange element 212 than the surface convexity of elements 58, 102, and 166, previously described. Ade11

ES 2 278 624 T3 furthermore, the fact that each element 212 is generally located parallel to the main tubular axis 218, but separated from it, allows all of them to compress inward and / or migrate around the circumference of the tubular axis when the catheter is passed through narrow or tortuous body cavities.

Another means of increasing the surface area of each heat exchange element is to modify its cross section away from a purely circular cross sectional geometry. Thus, Figure 12 illustrates, in cross section, a heat exchange element 220 alternatively provided with a plurality of outwardly projecting regions 222 and grooves 224. The overall size of the cross section, so to speak, fits within an imaginary circle 226, but has a larger outer surface area. Those skilled in the art will recognize that numerous cross-sectional configurations are possible for heat exchange elements that satisfy the dual requirements of increased surface area without increasing the overall cross-sectional size.

An alternative construction for the heat exchange elements is shown in Figures 13 and 14. A tubular catheter shaft 240 contains an inlet conduit for fluid flow 242 and an outlet conduit for fluid flow 244. Several heat exchange elements 246 are joined at only one end along the length of the tubular shaft. 240 so that they can float freely in the surrounding body fluid. Each heat exchange element 246 consists of an outer tube 248 that surrounds an inner tube 250. The distal end of the outer tube 248 is closed and the distal end of the inner tube 250 is open and terminates before the distal end of the outer tube. The inner tubes 250 define inside conduits that are in fluid communication with the inlet conduit 242. In addition, outlet conduit 244 is in fluid communication with the annular space between inner tube 250 and outer tube 248. In this manner, heat transfer fluid traveling through inlet conduit 242 of the catheter tubular shaft enters the inlet tube conduit, as indicated by arrows 252, and flows between the inner and outer tubes and enters the outlet conduit 244 of the tubular shaft, as indicated by arrows 254. The flow path for the heat exchange medium here includes what are known as heat exchange blanks. The outer surface of the outlet tube is surrounded by a body fluid, blood for example, and, as heat transfer fluid circulates through the tubes, heat can be transferred between the heat transfer fluid and the body fluid. It should be noted that the direction of the fluid flow could be reversed and the flow structure need not be exactly as illustrated. For example, the inlet and outlet ducts of the tubular shaft do not need to be concentric; other configurations are possible.

A further alternative construction for the heat exchange elements is shown in Figures 15-20. This exemplary embodiment includes a proximal manifold 300 and a plurality of heat exchange elements 302, and therein the proximal portions of the individual heat exchange elements 302 are grouped or positioned within a shaft or tubular sleeve 306. The distal portions of the heat exchange elements 302 project outwardly from the distal end of the sleeve 306 and extend freely beyond it.

With particular reference to Figure 15, the catheter includes a guidewire tube 304 that extends through proximal manifold 300 and beyond the distal ends of heat exchange elements 302. The sleeve 306 may consist of a flexible tubular structure that substantially surrounds the multiple heat exchange elements 302 (consisting of flexible tubes) and the wire guide tube 304, along substantially the entire length of the catheter. The portions of the heat exchange elements that protrude beyond the distal end of the sleeve 304 define the heat exchange region of this particular embodiment of the invention. Optionally, tubular sleeve 306 may be flared at proximal end 308 to facilitate convergence of multiple heat exchange elements 302 into a single low profile tube.

Heat exchange elements 302 are unrestricted in their mobility and float freely with body fluid past a distal end 310 of tubular sleeve 306. The illustrated embodiment shows eight heat exchange elements 302, although other numbers are possible. . Wire guide tube 304 is generally stiffer than heat exchange elements 302. Initially, a temporary fastening means (not shown) may be provided to engage the loose portions of the heat exchange elements 302 and the wire guide tube 304, or a temporary adhesive that releasably binds the fastening elements. heat exchange to the tube for the wire guide. Such attachment means may be in the form of an elastomeric band surrounding all heat exchange elements 302 and wire guide tube 304. Such a weak and temporary bond can be overcome when elements 302 are inflated during catheter operation, or it can be undone by other suitable means.

As seen in the detailed view of Figure 17 and in the cross section of Figure 18, the heat exchange elements 302 consist of coaxial tubes, each of which is provided with an inner conduit 312 and an outer conduit 314 At the distal end 316 of each of the elements 302, the outer conduit 314 is closed, and the inner conduit terminates before this distal end. Flow arrows show heat exchange medium passing distally through inner conduit 312 and being redirected at distal end 316 to travel proximally through outer conduit 314.

As seen in Figure 16, the proximal manifold 300 comprises a container generally divided into two equal chambers: an inlet chamber 318 and an outlet chamber 320. The inlet chamber 318 has an inlet port for fluids 322, and the Outlet chamber 320 has a fluid outlet port 324. The two chambers 318, 320 are separated by a divider plate 326. Each of the heat exchange elements 302 passes through a face plate 328 of the manifold 300.

As seen in Figures 16 and 17, the inner conduits 312 are defined within the tubes

Inlet 330 terminating in inlet chamber 318. Similarly, outer conduits 314 are defined within outlet tubes 332 terminating in outlet chamber 320. Inlet and outlet tubes 330 , 332 pass through holes 334 formed in face plate 328, as seen in Figure 19. Each of holes 334 fluid tightly seals around tubes 330, 332. There is also a center hole 335 in face plate 328 for passage of wire guide tube 304. Wire guide tube 304 extends tightly through center hole 335. Referring to Figure 20, divider plate 326 includes a fluid tight center hole 338 around wire guide tube 304. The wire guide tube 304 follows through a single hole 340 in the rear plate of the manifold 300. Each inlet tube 330 passes through a hole 336 in divider plate 326 which is fluid-tight with respect to it.

When in operation, the catheter is inserted into a blood vessel and heat exchange fluid is introduced through the inlet port 322 into the inflow chamber 318. The heat exchange fluid then passes to the open proximal ends of the each of the inlet tubes 330, and into the internal conduit 312 of each of the heat exchange elements 302. The fluid passes the entire length of each of the heat exchange elements 302 until it is redirected at the distal end 316 into the outer conduit 314. The fluid then travels proximally through the outer conduit 314, as shown. see in Figure 17, until it reaches the proximal ends of each of the 332 outlet tubes. If the heat exchange elements 302 are initially in a collapsed configuration, the flow of heat exchange fluid inflates them and can cause the rupture of a fastener means and subsequent separation of each of the elements. Ultimately, the fluid passes into the outlet chamber 320 and exits the manifold 300 through the outlet port 324. In this manner, the heat exchange fluid can be caused to flow through the heat exchange catheter. As the heat exchange fluid returns proximally through the outer conduit 314, it exchanges heat with the blood flowing over the surface of the elements through the outer wall of the heat exchange elements 302.

Although the example given shows fluid flowing distally through inner conduit 312, and proximally through outer conduit 314, those skilled in the art will realize that the direction of flow can sometimes be reversed simply by introducing fluid from heat exchange in the inlet chamber as it is withdrawn from the outlet chamber. Generally, it is desirable to have a countercurrent heat exchange, that is, for the blood flow to go in the opposite direction to the flow of the heat exchange fluid in the outer conduit 314. If the heat exchange elements 302 are in the bloodstream such that the distal ends of the elements are downstream, and blood flows from the proximal to the distal end along the catheter surface, it is desirable that the flow of Inlet of the heat exchange fluid occurs through the inner conduit 312 and it is also desirable that the outflow of heat exchange occurs through the outer conduit 314. This type of flow is preferred for the catheter with free-floating heat exchange elements at the distal end, because although blood flows from the distal to the proximal end, the elements tend to descend and float back toward the proximal end of the catheter. In such a configuration, countercurrent flow is achieved if the heat exchange fluid flows back out of the catheter through external conduit 314.

Referring now to an alternate embodiment shown in Figures 26-31, a heat exchange catheter 350 of the present invention includes a plurality of heat exchange elements that are formed from a single conduit tubing circuit. extending the entire length of the catheter. The inlet end of each of the single conduit tubes is open to an inlet reservoir of a distributor, and the outlet end is open to an outlet reservoir. The heat exchange fluid circulates along the entire length of each of the heat exchange elements.

Referring in particular to Figure 21, a single circuit heat exchange catheter 350 consists of a proximal distributor 352, a plurality of coaxial heat exchange elements 354, a tube 356 for the wire guide, and a sleeve. proximal tubular 358 that surrounds heat exchange elements in the proximal region of the catheter. The illustrated catheter 350 shows eight such heat exchange elements 354, each comprising circuits of elongated single conduit tubes. Of course, those skilled in the art will understand that the number of heat exchange elements can vary. The proximal end 360 of the tubular sleeve 358 may be flared to facilitate a convergence of the multiple heat exchange elements 354 into a single, lower profile tube.

At the distal end 362 of the sleeve, the heat exchange elements 354 are not restricted in their mobility and can float freely. Wire guide tube 356 is generally stiffer than heat exchange elements 354, and a loose fit (not shown) can be formed between them. For example, an elastomeric band can be used that surrounds all heat exchange elements 354 and wire guide tube 356. Alternatively, it can replace the above any weak and temporary fixation means that can be overcome when the elements 354 are inflated.

As seen in Figure 22, the proximal manifold 352 defines within it two reservoirs: a reservoir for inflow 368 and a reservoir for outflow 370. A divider plate 372 separates the two reservoirs 368, 370. A port for Inflow 374 communicates with the inflow reservoir 368, while an outflow port 376 communicates with the outflow reservoir 370. A face plate 378 forms the front surface of the dispenser 352, as seen in the plan view of Figure 25.

The heat exchange elements 354 consist of long, thin-walled tubes, each defining a single conduit 364 inside. Each tube has an open end 366 positioned in the reservoir.

ES 2 278 624 T3 for inflow 368 and extends distally through sealed openings 380 in divider plate 372 (Figure 26). The tubes pass through outflow reservoir 370 and through sealed openings 382 in face plate 378 (Figure 25). The tubes continue distally, converging on the flared portion 360 of the tubular sleeve 358, and emerging from a distal end 362. Each of the heat exchange elements 354 extends for a distance to a distal bend 384, seen in Figure 23. The distal flow of heat exchange fluid is thus redirected proximally at the distal bend 384. Return tube passes back through one of the openings 382 in the face plate 378, and ends at the outflow reservoir 370.

A wire guide tube 356 passes completely through the manifold 352, extending through a proximal wire guide hole 388, a central opening 390 in divider plate 372, and a central opening 392 which There is on the face plate 378. The tube 356 for the wire guide is hermetic with respect to both reservoirs 368, 370 of the manifold 352.

When in operation, heat transfer fluid (represented by the arrows in the various Figures) is introduced into the inflow reservoir 368 through inflow port 374. The pressurized fluid passes to the open ends of each of the tubes of the heat exchange elements 354, flows the full length of the tube and is redirected at the elbow 384, and then flows proximally, emptying into the reservoir for flow. outlet 370. The fluid then exits through outlet port 376. As previously indicated, those skilled in the art will understand that the direction of flow can be easily reversed without altering the basic principles of the invention. In this exemplary embodiment, however, the heat exchange fluid will be flowing in both directions in a tube in contact with the blood flow, and therefore there is both a flow in the direction of the current and a flow in the direction contrary. Thus, the direction of flow through the tubes becomes less significant than in the coaxial system described above.

The heat exchange elements of the present invention can be made from a variety of materials, the primary consideration being their biocompatibility. The elements are impervious to fluids, preferably made of some type of polymer, and flexible. A particularly useful material is polyethylene terephthalate (PET), which can be extruded and blown to form thin-walled hollow filaments.

Although a specific embodiment of the invention has been described above for illustrative purposes, it will be apparent to those skilled in the art that numerous variations of the details can be made without departing from the invention as defined in the appended claims. By way of example and not in a way that implies limitation, where heat is exchanged between the circulating fluids, as occurs between the circulating heat exchange fluid in this catheter and the circulating blood, it has been found that the heat exchange is more efficient if there is a counter current flow between the fluids, that is, the fluids flow in opposite directions. In the example given here, blood may be flowing past heat exchange filaments from proximal to distal end, or distal to proximal, depending on the mode of insertion of the catheter. For example, if the catheter is inserted into the inferior vena cava through an incision in the jugular vein, blood would flow over the heat exchange region from the distal end to the proximal end of the catheter (i.e., retrograde flow), whereas if the catheter is inserted into the inferior vena cava from an incision in the femoral vein, blood would flow past the heat exchange region from the proximal to the distal end (ie, antegrade flow). To achieve counter current flow between the blood and the heat exchange fluid, the inlet and outlet conduits of the tubular shaft can be reversed without departing from the invention as described.

Contents4

23 members in 9 offices

This recordMember, by publication datePriority claim

Priority claims5

Priority claims
Document	Office	Kind	Date
19990378578	United States of America	–	1999-08-20
37857899	United States of America	A	1999-08-20
37857899	United States of America	A	1999-08-20
00952284378578	–	–	–
US19990378578	–	–	–

Members23

Family members, oldest first
Document	Office	Kind
CA2382328A1	Canada	A1	2001-03-01
WO0113809A1	World Intellectual Property Organization (WIPO)	A1	2001-03-01
AU6501000A	Australia	A	2001-03-19
US6264679B1	United States of America	B1	2001-07-24
US2001044644A1	United States of America	A1	2001-11-22
EP1207801A1	European Patent Office (EPO)	A1	2002-05-29
WO03009230A1	World Intellectual Property Organization (WIPO)	A1	2003-01-30
JP2003507119A	Japan	A	2003-02-25
US2003053669A1	United States of America	A1	2003-03-20
EP1207801A4	European Patent Office (EPO)	A4	2003-05-02
US6702840B2	United States of America	B2	2004-03-09
EP1412919A1	European Patent Office (EPO)	A1	2004-04-28
US2004167593A1	United States of America	A1	2004-08-26
JP2004535874A	Japan	A	2004-12-02
EP1207801B1	European Patent Office (EPO)	B1	2006-12-20
AT348574T	Austria	T	2007-01-15
ATE348574T1	Austria	T1	2007-01-15
DE60032491D1	Germany	D1	2007-02-01
ES2278624T3This record	Spain	T3	2007-08-16
DE60032491T2	Germany	T2	2007-10-04
JP2010207619A	Japan	A	2010-09-24
JP4610825B2	Japan	B2	2011-01-12
CA2382328C	Canada	C	2012-05-22

Heat exchange catheter with discrete heat exchange elements

Abstract

Term

ES 2 278 624 T3

DESCRIPTION

ES 2 278 624 T3

ES 2 278 624 T3

Priority claims5

Members23

Numbers

Titles2

Classification