OXYGENATOR WITH A HOUSING WALL

Abstract

An oxygenator with a housing wall, which delimits a housing space with a blood inlet and a blood outlet, a gas inlet and a gas outlet, has a heating element which is arranged in the oxygenator between blood inlet and blood outlet in order to control the temperature of blood flowing through the housing space. For this purpose, the oxygenator has a radiation source and a receiver. The radiation source can be an infrared emitter and the receiver a matte-black surface, or the radiation source is an induction coil and the receiver has a material capable of induction. In a method for regulating the heat output on a heating element of an oxygenator, the through-flow of the blood through the oxygenator and the power of a pump acting on the through-flow are measured, and the heating power is adjusted in accordance therewith.

Claims

1. An oxygenator (10) with a housing wall (11), which delimits a housing space (12), with a blood inlet (2), a blood outlet (3), a gas inlet (4) and a gas outlet (5), and a heating element to control the temperature of the blood flowing through the housing space (12), wherein the heating element has a radiation source and a receiver (13), which converts the radiation from the radiation source into heat.

2. The oxygenator in accordance with claim 1, wherein the radiation source (30) emits infrared light (31), and the receiver (13) has a dark, preferably matt-black, surface (14).

3. The oxygenator in accordance with claim 2, wherein the wavelength of the radiation source (30) is adjustable.

4. The oxygenator in accordance with claim 2, wherein the absorption capacity of the receiver (13) can be altered in a regulated manner.

5. The oxygenator in accordance with claim 1, wherein the radiation source (30) has an induction coil, and the receiver (13) has a material capable of induction.

6. The oxygenator in accordance with claim 1, wherein the radiation source (30) can be aligned in a regulated manner.

7. The oxygenator in accordance with claim 1, wherein the radiation source (30) has a fan.

8. The oxygenator in accordance with claim 1, wherein the radiation source (30) is a device that can be set apart from the housing space (12).

9. The oxygenator in accordance with claim 1, wherein the radiation source (30) is arranged on a housing holder.

10. The oxygenator in accordance with claim 1, wherein the radiation source (30) is arranged concentrically with the housing space (12), preferably radially within the housing space (12).

11. The oxygenator in accordance with claim 1, wherein the receiver (13) is arranged in the housing wall (11).

12. The oxygenator in accordance with claim 1, wherein the receiver (13) is arranged in the housing space (12).

13. The oxygenator in accordance with claim 1, wherein the oxygenator has membranes such as, in particular, hollow fibers (17).

14. The oxygenator in accordance with claim 1, wherein it has at least one temperature sensor (24).

15. The oxygenator in accordance with claim 1, wherein it has a temperature regulation device (25).

16. The oxygenator in accordance with claim 15, wherein the temperature regulation device (25) is arranged in a control console (26).

17. The oxygenator in accordance with claim 15, wherein the temperature regulator (25) individually adjusts or regulates the temperature of the receiver (13) at various locations.

18. The oxygenator in accordance with claim 1, wherein it has an automatic cut-off device for use in the event of overheating.

19. The oxygenator in accordance with claim 1, wherein the receiver (13) delivers a different heating power at various locations in the housing space (12).

20. The oxygenator in accordance with claim 1, wherein the receiver (13) has a plurality of receiver components (28, 29, 30), which can be positioned at various locations of the oxygenator.

21. The oxygenator in accordance with claim 19, wherein the receiver (27) has a plurality of receiver components (28, 29, 30), which can be controlled separately from one another.

22. The oxygenator in accordance with claim 1, wherein the receiver (13) is arranged in the oxygenator between the gas inlet (4) and the gas outlet (5), so as to control also the temperature of gas flowing through the housing space (12).

23. The oxygenator in accordance with claim 1, wherein the housing wall (11) has only four fluid passages (2, 3, 4, 5) leading to the external environment.

24. The oxygenator in accordance with claim 1, wherein it has at least one connector in which a part of the receiver (13) is arranged.

25. The oxygenator in accordance with claim 1, wherein the receiver has a heat conduction device for the distribution of heat from the receiver (13) in the housing space (12).

26. The oxygenator in accordance with claim 1, wherein it has an insulating layer to insulate the blood flowing in the housing space.

27. The oxygenator in accordance with claim 1, wherein it has a reflective layer so as to reflect heat radiation from the blood flowing in the housing space.

28. The oxygenator in accordance with claim 26, wherein the layer is transparent, or partially transparent.

29. A method for regulating the heat output at a heating element (13) of an oxygenator (10), in which the flow of blood through the oxygenator (10) or the power of a pump governing the through-flow are measured, and the heating power is adjusted in accordance therewith.

30. The method in accordance with claim 29, wherein the heating element (13) has a plurality of separately controllable heating components (28, 29, 30), which are controlled such that the temperature difference between the temperature of the blood at the heating component (28, 29, 30), and the temperature of the heating component (28, 29, 30), does not exceed a predefined value.

Description

[0043] Examples of embodiment of inventive oxygenators are shown in the figures and are described in more detail below.

[0044] Here:

[0045] FIG. 1 shows an oxygenator of known art with blood, gas and water flows,

[0046] FIG. 2 shows schematically an oxygenator irradiated with infrared light,

[0047] FIG. 3 shows a plan view of the oxygenator shown in FIG. 2,

[0048] FIG. 4 shows schematically an oxygenator with layered membrane fibre mats and a semi-permeable printed receiver surface,

[0049] FIG. 5 shows schematically an oxygenator with layered mats and receiver components that can be separately controlled,

[0050] FIG. 6 shows schematically the interaction of components of an algorithm,

[0051] FIG. 7 shows schematically the average temperatures plotted against time,

[0052] FIG. 8 shows schematically the temperature plotted against time at a first location, and

[0053] FIG. 9 shows schematically the temperature plotted against time at a second location.

[0054] The oxygenator 1 shown in FIG. 1 has a blood inlet 2 and a blood outlet 3. A gas supply is provided by a gas inlet 4 and a gas outlet 5. In the heat exchanger, hollow fibres are provided, through which water flows in the radially inner region, as are semi-permeable hollow fibres, through which gas flows in the radially outer region. By this means, heating takes place in the radially inner region by means of water entering at water inlet 8, and leaving at water outlet 9, while a gas exchange takes place in the radially outer region 7. For a more detailed explanation of such an oxygenator, reference is made to EP 765 683 B1.

[0055] In the case of the oxygenator shown schematically in FIG. 2, the basic structure is essentially retained, and the water inlet 8, the water outlet 9 and the hollow fibres through which water flows, are dispensed with. The oxygenator 10 has a housing wall 11 that surrounds a housing space 12. As shown in FIG. 1, this housing space 12 has a blood inlet 2 and a blood outlet 3, and a gas inlet 4 and a gas outlet 5. A semi-permeable matt-black printed surface 14 arranged in the housing wall 11 serves as a receiver 13, which is wound evenly around the housing space 12 in the form of a film. The film 14 forms a receiver, which is heated when a voltage is applied to the electrical terminal connections 15, 16 such that the radiation source 30 emits infrared light 31.

[0056] The oxygenator can have, as in the examples of embodiment in FIGS. 1 to 3, wound hollow fibre mats 17 arranged in the housing space 12, or, as shown in FIGS. 4 and 5, stacked mats 18 of hollow fibre membranes arranged between two plates 19 and 20. In the example of embodiment shown in FIG. 4, a semi-permeable matt-black printed surface 21 is provided on the upper plate 20. A radiation source 22 is connected to an electrical terminal connection in order to direct infrared radiation onto the printed surface 21.

[0057] FIG. 5 shows hollow fibre mats 27 between two plates 19 and 20, of which the upper plate 20 has a semi-permeable matt-black printed surface 21. Schematically three receiver components 28, 29, 30 are indicated, which can have different radiation-absorption capacities, or can be irradiated in different manners, so to produce different amounts of heat at various locations on the oxygenator. In particular, the receiver components 28, 29 and 30 can be controlled such that a certain temperature difference between the receiver component and the blood temperature on the receiver component is not exceeded.

[0058] FIG. 3 shows schematically a temperature sensor 24 connected to a temperature regulation device 25 mounted in a control console 26.

[0059] In FIGS. 6 to 9 the algorithmic control by time intervals is shown in an optimised form. A model is determined from a real gas exchanger. In this gas exchanger model, which is drawn in FIG. 6 as an oxygenator model 114 for purposes of measurement point location, measurement points are defined and the material properties, required as parameters for the calculations, are determined. The temperature can be measured at all measurement points.

[0060] The sensors, blood and gas parameters (KD) already present in an ECMO system are fed into the control console. A desired temperature is then compared with a measured temperature, taking into account control console values (KD). This is undertaken individually for each measurement point and each heating element. As a result various tolerances ensue between the measured values and the desired temperatures. The appropriate heating frequency, with frequency of heating occurrence and heating intensity, is then selected from all parameters for each heating element, in order to achieve and subsequently maintain the desired temperature with as little trauma to the blood as possible. These frequencies can be stored in a table to facilitate the control of the oxygenator subsequently.

[0061] In the algorithm shown in FIG. 6, the user 101 sets the desired temperature 102, which is entered into the control console 103. The blood flow, gas flow and pressure parameters 104 are also entered into the control console. The control console initiates a temperature measurement 105 so as to determine average temperatures 106, 107 and 108 at different measurement points of the oxygenator. The comparison 109 between the desired temperature (WT) and the average measured temperature at the various locations leads to the difference value (AG). This value is set off against the temperature deviations 110 determined at the various locations, and the control console data (KD) such as blood flow. This provides the fundamentals for an individual regulation 111 of the heating elements on the basis of the comparison (AG) between the temperature deviations (AT) and the control console data (KD). The heating elements 112 can be controlled with these values. In addition, the individual regulation can also be governed by the heating algorithm 113, which is selected from a table and ensues from the measured parameters. In addition, any alteration in the receiver (colour, position, switching, etc.) can be used in addition to the heating algorithm, or instead of the heating algorithm, to govern the control process.

[0062] The heat output of the heating elements 112 acts on the temperatures 105 measured with the temperature measurement process, resulting in a feedback onto the measured temperatures.

[0063] FIG. 7 shows the desired temperature 120 in a coordinate system with the temperature in C. plotted against time in seconds. The lambda value indicates the thermal conductivity, which is influenced by the material constants, and which leads to temperature peaks being absorbed. X.sub.1, X.sub.2, X.sub.3 and X.sub.4 are examples of temperature measurement points 122.

[0064] FIGS. 8 and 9 show the temperature profile plotted against time for two measurement points. In FIG. 8 the temperature profile 123 at a first measurement point is plotted against time as a wavy line, which fluctuates about a temperature 124 and defines a delta T (T) 125. Similarly, in FIG. 9, the current temperature 126 at a second location is recorded against an average temperature 127, resulting in a temperature deviation delta T (T) 128.