Patent Description:
Oxygenators are devices used for extracorporeal oxygenation of blood. Such oxygenators are used e.g. in heart-lung machines or in extracorporeal membrane oxygenation (ECMO) devices. Commonly used devices of this type are membrane oxygenators by means of which embolisms can reliably be avoided to a very large extent. With the aid of gas mixers and flow meters the transfer of oxygen and carbon dioxide can be controlled reliably.

In the oxygenator, the blood in a patient's extracorporeal blood circulation is not only oxygenated but also warmed or cooled. In particular, hypothermia is very important for reducing the oxygen consumption of the patient's organism. For warming or cooling the blood in the extracorporeal blood circulation, the oxygenator comprises a heat exchanger. A heat exchanging medium flows through the heat exchanger and transfers a heat quantity to the blood (blood warming) or absorbs a heat quantity from the blood (blood cooling). The heat exchanging medium is usually supplied to the heat exchanger by a pump unit and, after heat exchange with the blood has taken place, it is discharged from the heat exchanger by another pump unit. The heat exchanging medium, e.g. water, is previously heated or cooled in a heater/cooler (a hypothermia device) before it is conducted to the heat exchanger. Due to its size and complex structure, the heater/cooler is configured e.g. separately from the heart-lung machine.

The heater/cooler may be contaminated with germs from inside. Hence, there is the risk that equipment and the atmosphere in the operating room may be contaminated and that germs will thus finally enter the patient's blood circuit. Furthermore, the heaters/coolers according to the prior art have a comparatively complex structural design and are thus fault-prone. Systems for extracorporeal blood circulation comprising i. an oxygenator, a heat exchanger and a heater/cooler are disclosed in <CIT>, <CIT>, <CIT> and <CIT>.

Hence, it is an object of the present disclosure to provide for an oxygenator including a heater/cooler, which operates reliably and in a trouble-free and hygienic mode.

The invention is defined by the features of independent claim <NUM>.

A system for extracorporeal blood circulation is provided, which comprises an oxygenator including a heat exchanger configured for warming or cooling blood of an extracorporeal blood circulation of a patient, and a heater/cooler configured for exchanging a quantity of heat with the heat exchanger of the oxygenator (i.e. for cooling or heating the heat exchanger), wherein the heater/cooler is or comprises a thermoelectric heater/cooler.

Furthermore, the heater/cooler is connected to the heat exchanger by a thermal connecting element (contact element without using any fluid for transferring the heat), whereby a high efficiency of heat exchange between the heat exchanger and the heater/cooler can be achieved and, in particular, the use of a circulating heat exchanging medium, which is conducted through the heat exchanger, can be dispensed with. Hence, pumps for conveying such a heat exchanging medium are not necessary either. The thermal connecting element may comprise a thermally highly conductive material, such as a thermally highly conductive metal.

Here, and in the embodiments described below, the system may be or may comprise a heart-lung machine, an extracorporeal membrane oxygenation (ECMO) device or a minimized extracorporeal circulation (MECC) device. Here, and in the embodiments described in the following, the thermoelectric heater/cooler may comprise at least one Peltier element, in particular, a plurality of Peltier elements which operate in parallel. A plurality of Peltier elements may be provided such that they are connected in series.

It follows that the heater/cooler can heat or cool the heat exchanger directly. When the heat exchanger is cooled by the thermoelectric heater/cooler (Peltier elements) to a temperature below the blood temperature, the blood will be cooled, and when the heat exchanger is heated by the heater/cooler to a temperature above the blood temperature, the blood will be warmed. It follows that a fully "dry" unit for supplying a quantity of heat to the heat exchanger of the oxygenator can be provided, said unit being almost maintenance-free and allowing a significant reduction of the risk of bacterial contamination (cf. the above description).

Furthermore, it is provided a system for extracorporeal blood circulation, comprising an oxygenator which includes a heat exchanger configured for warming or cooling blood in the extracorporeal blood circulation of the patient, and a reservoir configured for storing a heat exchanging medium and connected to the heat exchanger, wherein the heater/cooler comprises a thermoelectric heater/cooler, and the heater/cooler is connected to the reservoir and configured to heat or cool the heat exchanging medium stored in the reservoir.

It follows that a circulation of a heat exchanging medium (to and from the oxygenator heat exchanger) for cooling or warming a patient's blood may be provided, where the cooling or heating of the heat exchanging medium is accomplished with the aid of the heater/cooler according to the present disclosure.

The reservoir may be connected to the oxygenator heat exchanger through hoses and/or tubes. The heater/cooler may be connected to the reservoir by a thermal connecting element. Heating/cooling is exchanged between heater/cooler and the reservoir.

According to some embodiments, the system comprises an additional heat exchanger which is connected to the reservoir, the heater/cooler being connected to the additional heat exchanger for exchanging a quantity of heat.

Furthermore, the system may comprise a unit adapted for providing a fluid to the blood of the patient, in particular, a cardioplegic solution, and wherein the heater/cooler (<NUM>) is connected to the unit for providing the fluid and configured to heat or to cool said fluid. It follows that, in addition to the function of exchanging heat with the heat exchanger of the oxygenator and of warming or cooling a patient's blood in this way, the heater/cooler can fulfill the function of heating or cooling other fluids (such as a cardioplegic solution) used e.g. in a heart-lung machine.

In the case of all the above described embodiments, the heater/cooler comprises a cooling module with a plurality of Peltier elements and a heating module without any Peltier elements. The heating module comprises comprise a heating coil. Since the capacity of Peltier elements is limited, the Peltier elements are thus exclusively used for a cooling function. A heat exchanging medium stored in a reservoir (see above) can already be cooled or heated, prior to starting the actual operation, with the aid of the cooling module or the heating module.

In the following, embodiments of a device according to the present disclosure will be described. The embodiments described are to be regarded in any respect as being only illustrative and non-restrictive, and various combinations of the specified features are included in the present disclosure.

<FIG> is a diagram illustrating a schematic representation of a system, according to embodiments of the present disclosure. The system comprises an oxygenator <NUM> with a heat exchanger <NUM>. The blood of a patient is circulated via the lines <NUM> and the oxygenator <NUM> with the aid of a pump unit <NUM>. The blood is oxygenated in the oxygenator <NUM> and cooled or warmed, as required, with the aid of the heat exchanger <NUM>. The system shown in <FIG> may be part of a heart-lung machine, an extracorporeal membrane oxygenation (ECMO) device or a minimized extracorporeal circulation (MECC) device, which may comprise numerous additional elements, as known from the prior art. The oxygenator <NUM> may be a membrane oxygenator.

A thermoelectric heater/cooler <NUM> is connected to the heat exchanger <NUM> via a thermal connecting element (contact element) <NUM>. The thermal connecting element <NUM> may comprise a thermally highly conductive metal. A transfer of heat between the heat exchanger <NUM> of the oxygenator <NUM> and the heater/cooler <NUM> takes place directly via the thermal connecting element <NUM> without any liquid heat exchanging medium being required.

According to the invention, the heater/cooler <NUM> comprises Peltier elements 14a, which allow a substantially maintenance-free operation.

Additional exemplary embodiments are illustrated in <FIG>. Elements corresponding to those shown in <FIG> are designated by like reference numerals. The systems shown in <FIG> comprise an oxygenator <NUM> with a heat exchanger <NUM>. The oxygenator <NUM> may be a membrane oxygenator with membranes produced e.g. from polypropylene or polyethylene. The heat exchanger <NUM> may be a spiral tube made of stainless steel or it may comprise a plurality of hose sections.

The blood of a patient is circulated via the lines <NUM> and the oxygenator <NUM> with the aid of a pump unit <NUM>. The blood is oxygenated in the oxygenator <NUM> and cooled or warmed, as required, with the aid of the heat exchanger <NUM>. The systems shown in <FIG> may be part of a heart-lung machine, an extracorporeal membrane oxygenation (ECMO) device or a minimized extracorporeal circulation (MECC) device. The oxygenator <NUM> may be a membrane oxygenator.

A heat exchanging medium is supplied from a reservoir <NUM> via lines <NUM> with the aid of a pump unit <NUM> to the heat exchanger <NUM> of the oxygenator <NUM>, and, when an exchange of heat with the blood in the patient's extracorporeal blood circulation has taken place, it is returned from said heat exchanger <NUM> to the reservoir <NUM>. The heat exchanging medium may e.g. be water or glycerine. In embodiments shown in <FIG>, a thermoelectric heater/cooler <NUM> is connected directly to the reservoir <NUM> for heating or cooling the heat exchanging medium. The thermoelectric heater/cooler <NUM> may, for example, be arranged in or on the reservoir <NUM>. Embodiments shown in <FIG> differ from those shown in <FIG> insofar as, for heating or cooling the heat exchanging medium stored in the reservoir <NUM>, a further heat exchanger <NUM> is used, which is connected to a heater/cooler <NUM> via a thermal connection <NUM>. In embodiments shown in <FIG>, the heater/cooler <NUM> comprises a cooling module with Peltier elements 14a and a heating module with a heating coil. These modules may also be provided in the embodiments shown in <FIG> and <FIG>.

The embodiments shown in <FIG> can be obtained by suitably retrofitting existing conventional systems, or completely new systems may be formed. Advantageously, these embodiments comprise thermoelectric heaters/coolers <NUM>, in particular heaters/coolers with Peltier elements, thus allowing a substantially maintenance-free, reliable operation as regards the heater/cooler <NUM>. Through the lines <NUM>, a heat exchanging medium is, however, circulated via the heat exchanger <NUM> of the oxygenator <NUM>, and this entails the risk of contamination of the blood to be oxygenated, if the circuit of the heat exchanging medium is not air tight (i.e. closed to the atmosphere). This risk is avoided in the case of the embodiments shown in <FIG>. In point of fact, the prejudice that the heat exchanger <NUM> of the oxygenator <NUM> could only be operated via a heat exchanging medium existed in the prior art, but it turns out that a direct heat transfer via a thermal connecting element without the use of a heat exchanging medium is possible for reliably cooling or warming the blood of an extracorporeal blood circulation.

Claim 1:
A system for extracorporeal blood circulation, comprising:
an oxygenator (<NUM>) which includes a heat exchanger (<NUM>) configured for warming or cooling blood in the extracorporeal blood circulation of a patient, and
a heater/cooler (<NUM>) configured for exchanging a heat quantity with the heat exchanger (<NUM>),
wherein the heater/cooler (<NUM>) comprises a cooling module including a plurality of Peltier elements (14a) and
wherein the heater/cooler (<NUM>) is connected to the heat exchanger (<NUM>) by a thermal connecting element (<NUM>) and characterized in that the heater/cooler (<NUM>) comprises a heating module without any Peltier elements and at least one heating coil (14b), wherein all of the Peltier elements are used exclusively for a cooling function.