WO2005068011A1

WO2005068011A1 - An apparatus and a method for controlling a fluid of extracorporeal circulation systems

Info

Publication number: WO2005068011A1
Application number: PCT/EP2005/000284
Authority: WO
Inventors: Uwe Mehlhorn
Original assignee: Cell Center Cologne Gmbh
Priority date: 2004-01-13
Filing date: 2005-01-13
Publication date: 2005-07-28
Also published as: DE102004001861A1

Abstract

An apparatus for controlling a fluid of extracorporeal circulation system comprises: at least three conduits for transporting said fluid therethrough and a control member which connects in a first position a first conduit and a second conduit of said at least three conduits with each other such that a passage of said fluid through said first conduit and said second conduit is possible, while a passage of said fluid through a third conduit of said at least three conduits is not possible, and wherein in a second position the control member connects said first conduit and said third conduit such that a passage of said fluid through said first conduit and said third conduit is possible, while a passage of said fluid through said second conduit is not possible, wherein the respective conduit through which a passage of fluid is not possible, can be rinsed or vented via the control member.

Description

An apparatus and a method for controlling a fluid of extracorporeal circulation systems

The invention refers to an apparatus and a method for controlling a fluid and particularly to an apparatus and a method for controlling a fluid of extracorporeal circulation systems.

Extracorporeal circulation systems are used in heart surgery in order to temporarily replace the functions of the heart and/or the lung. An example for an extracorporeal circulation system is a heart-lung machine which is able to substitute the pumping function of the heart and the gas exchange function of the lung of a patient A heart-lung machine enables the correction of a cardiac defect or the treatment of cardiac diseases at an opened, stopped or beating but not pumping heart. Examples are heart valve surgery or aneurysma surgery and bypass surgery being performed in cases of coronary heart diseases and angina pectoris. In order to maintain the blood circulation during such procedures, extracorporeal circulation systems comprise a first conduit system between the right atrium of the heart and a gas exchanger outside the patient's body enabling the gas exchange by discharging CO and enriching the blood with oxygen. Blood being enriched with oxygen is transported back to the patient's body via a second conduit system between the gas exchanger and the patient's aorta so that the patient's organs are supplied with oxygen and substrates. After passing the capillary area, the blood being low in oxygen and enriched with CO₂ accumulates in the venous system and is transported via the first conduit system to the gas exchanger where the circulation starts again.

In case that obstructions occur in the first and/or the second conduit system due to depositions or the like, a constant and predetermined pressure of the circulating blood volume flow is no longer ensured. To maintain the flow velocity and the flow pressure of the blood in the circulation system within close tolerances, the conduit systems must be separated from the circulation system and replaced by new conduit systems which have to be connected to the circulation system. During the steps of separating, replacing and connecting, the patient is not connected to the vital extracorporeal circulation system. This situation bears high risks for the patient. A similar situation occurs when a patient who is for example connected to a stationary extracorporeal circulation system has to be connected to another, for example mobile circulation system. In this case, the conduit systems have to be disconnected from the stationary system and to be connected to the mobile system. During these steps, the blood circulation is temporarily interrupted which bears high risks for the patient. Another reason for changing from a first circulation system to a second circulation system may lie in the fact that a service interval of a component of the first circulation system is reached.

The invention solves the object to provide an apparatus and a method for controlling a fluid of extracorporeal circulation systems wherein the replacement of a conduit system for the fluid or the change from one circulation system to another circulation system is possible within a short interruption time for the vital circulation so that the patient is not subjected to risks caused by the standstill of the fluid circulation during the change of the conduit system or the change of the circulation system.

The apparatus according to the invention which is used for controlling a fluid of extracorporeal circulation systems comprises: at least three conduits or lines through which a fluid can be transported, and a control member which connects in a first position a first conduit and a second conduit of said at least three conduits with each other such that a passage of said fluid through said first conduit and said second conduit is possible, while a passage of said fluid through a third conduit of said at least three conduits is not possible, and wherein said control member connects in a second position said first conduit and said third conduit such that a passage of said fluid through said first conduit and said third conduit is possible, while a passage of said fluid through said second conduit is not possible, wherein the respective conduit through which a passage of said fluid is not possible can be rinsed and vented by the control member.

Due to the fact that the respective conduit through which no passage of fluid is possible can be flushed and vented via the control member, said conduit may be prepared as a substitute conduit or additional conduit for connecting to an additional circulation system, while at the same time the fluid circulates in the conduits in which a passage of fluid is still possible, thus maintaining the circulation which is vital for the patient. By the use of such a control member it is possible to limit the interruption of the vital circulation to a very short time which is needed for the movement of the control member from the first position to the second position or from the second position to the first position. According to one embodiment of the invention, the control member has a hole through which the fluid can be transported. A predetermined cross section of the hole has an effect on the flow velocity and the flow resistance of the fluid in the circulation. Changes in the flow characteristics can be achieved easily by replacing the control member of the apparatus without varying other parameters of the circulation system.

According to a further embodiment, the control member comprises at least one opening through which a solution, for example a rinse solution, can be supplied to or discharged from one of the conduits which can be rinsed or vented. By using such an opening in the control member, both functions of the control member, namely controlling the flow of the fluid and enabling the conduit through which temporarily no fluid flows to be rinsed and vented, can be realized efficiently and easily in one component. Moreover, the whole conduit through which no fluid flows may be sterily rinsed and vented via such an opening by the control member without the risk that undesired residues remain for example in the transitional region between the control member and the conduit.

According to another embodiment, each conduit of the apparatus is connectable to a connection pipe. This is advantageous because the apparatus can be positioned in a greater distance from an extracorporeal circulation system. Thus, the apparatus comprising said three conduits and the control member can have a relatively compact design.

According to another embodiment, the connection pipe is a tube. This enables a stable connection to the circulation system. The tube stabilizes the spatial position of the apparatus and there is no need to use additional support means for the apparatus.

According to a further embodiment, the control pipe of the apparatus is a flexible tube. This enables an easy change of the spatial position of the apparatus and a more flexible positioning of the apparatus.

According to a further embodiment, the control pipe can be plugged onto the conduit of the apparatus. Hence, the control pipe can be connected fast and easily to the apparatus. This is particularly advantageous in mobile extracorporeal circulation systems. According to a further embodiment, the control pipe can be screwed onto the conduit of the apparatus. This is advantageous because the risk of a disconnection of the control pipe from the housing of the apparatus is very low. In case that a combination of plugs and screws is used for attaching the control pipe to the conduit of the apparatus, a safe transition from the conduits to the control pipes and a fast mounting time is achieved. An example for such a connection is the so call Luer-lock connection.

According to a further embodiment, each conduit of the apparatus is closable. This is advantageous in case that the rinsing and venting of a conduit through which no fluid flows is not desired. The closure of a conduit may for example be achieved by the use of an exchangeable blind flange.

According to a further embodiment, at least one connection pipe is closable. This is advantageous in case that the connection pipe is to be rinsed in a predefined region or in case that the connection pipe is to be separated from the circulation system without leaking of fluid contained in the connection pipe. The closure of the connection pipe may be achieved by the use of a blind flange, a blind plug or by pinching off the connection pipe.

According to a further embodiment, at least one connection pipe is fillable with rinse solution. For example, in case that a connection pipe is filled with rinse solution, the pipe can be rinsed and vented without the need to pinch off the two other remaining conduits of the device which for example transport fluid. Hence, the change from one connection pipe to another connection pipe can be prepared without the need to interrupt the fluid circulation.

According to a further embodiment, said at least three conduits of the apparatus constitute a Y-shaped form. I.e., one conduit is positioned on one side whereas two conduits are positioned on the opposite side. This enables fluid to be supplied through the conduit on the one side whereas the fluid can be discharged via one of the two conduits on the other side of the apparatus, thus enabling a change from one conduit to the adjacent alternative conduit. Due to the use of a Y-shaped form of the conduits, the fluid transport can be easily observed. According to a further embodiment, the control member can be moved via a rotational movement from the first position to the second position and from the second position to the first position. By changing the position of the control member via a rotational movement, a change of the fluid direction and or the fluid conduits can be performed in an easy and common way which is comparable to the opening and closing of a water tap.

According to a further embodiment, said at least three conduits are arranged parallel to each other. Hence, the fluid transport and the fluid discharge may only take place on one side of the apparatus. This is a preferred solution in cases where the apparatus is for example to be installed in a further housing and is only accessible from one side.

According to a further embodiment, the control member can be moved by a linear movement from the first position to the second position. This movement may be achieved by pushing and/or pulling and/or pressing the control member. Such an embodiment is advantageous under conditions of restrictive space where only a side wall of the control member (and not the center of the control member) is accessible so that a change of the position of the control member can only be achieved by pulling or pressing.

According to a further embodiment, the apparatus is adapted to connect a patient to a fluid pumping system. Besides the possibility to install the apparatus in an extracorporeal circulation system and to use the apparatus for controlling the fluid in this system, there exists the possibility to use the apparatus as a connecting part between a patient and a circulation system.

According to a further embodiment, the fluid pumping system is part of a ventricular assisting device (VAD). Such a ventricular assisting device supports the circulation when a heart failure occurs and the device may be used for patients awaiting a heart transplantation. Such a system comprises for example a blood pump and cannule connected directly to the heart. In this case, the inventive apparatus may be positioned between the cannulae and the blood pump.

According to a further embodiment, the apparatus is adapted to connect a patient to a fluid pumping system which can be used for assisting the left heart portion (LNAD) and/or for assisting the right heart portion (RNAD) and/or for assisting both heart portions (BiNAD). Hence, the apparatus may be used for different ventricular assisting systems.

According to a further embodiment, the apparatus is adapted to connect a patient to a fluid pumping system which is part of a heart-lung machine. A heart-lung machine temporarily fulfills the patient's heart and lung functions. The apparatus is adapted to be used not only in heart assisting systems but also in systems for assisting heart and lung functions.

According to a further embodiment, the apparatus comprises a control member which connects in the first position a fourth conduit and a fifth conduit to each other such that a passage of fluid through the fourth conduit and the fifth conduit is possible, while the passage of said fluid through a sixth conduit is not possible, wherein the control member connects in the second position the fourth conduit to the sixth conduit such that a passage of said fluid through the fourth and the sixth conduit is possible, while the passage of said fluid through the fifth conduit is not possible, and wherein the respective conduit through which the passage of said fluid is not possible can be rinsed and vented by the control member.

Hence, the control member may simultaneously control two different fluid passages. This apparatus has the same advantages as the apparatus described above only comprising three conduits. I.e., it is also possible to prepare substitute conduits or additional conduits for connecting to an additional circulation system, while at the same time fluid circulates in the conduits through which a fluid passage is possible, thus maintaining the vital circulation for the patient.

According to a further embodiment of the apparatus comprising six conduits, the first conduit, the second conduit and the third conduit are adapted for the passage of oxygen enriched blood from the fluid pumping system towards the patient and the fourth conduit, the fifth conduit and the sixth conduit are adapted for the passage of venous blood from the patient to the fluid pumping system. Hence, only a single apparatus is needed in order to control the fluid direction of both blood enriched with oxygen (so called "arterialized" blood) and venous blood simultaneously. Furthermore, a high level of security is achieved because the risk is very low that in a first apparatus for transporting venous blood a change of the conduit which transports the fluid is performed whereas in a second apparatus for transporting arterialized blood the change of such a conduit is not performed.

According to a further embodiment of the apparatus, the conduits which can be rinsed and vented are connectable to a further fluid pumping system. This enables the conduits to be connected to a further fluid pumping system which has to be connected after a predetermined time period without the risk for the patient that a stop of the fluid transport occurs. According to a further embodiment, the apparatus is adapted to connect a patient to a fluid pumping system wherein the fluid pumping system is a mobile fluid pumping system. Hence, the apparatus can also be used during a mobile mission (emergency mission).

According to a further embodiment of the apparatus, the control member does not connect any of the conduits with each other in a third position. In said third position or in an intermediate position which may lie between the first position and the second position, a smooth transition of the fluid flow from one conduit to another conduit can be achieved.

According to a further embodiment, the apparatus is used in an in vitro circulation system enabling a change from the first fluid pumping system to the second fluid pumping system and a change from the second fluid pumping system to the first fluid pumping system during continuous operation. Hence, a fluid supply of any time duration without interruption can be performed so that a change from one fluid pumping system to another fluid pumping system can be performed without stopping the circulation and without any risk for the patient.

According to a further embodiment, the apparatus is made substantially out of plastic or glass. These materials enable to provide a chemically inert surface for the fluid to be transported.

The inventive method for controlling a fluid of extracorporeal circulation systems by the use of the inventive apparatus comprises: positioning the control member in a first position such that the first conduit and the second conduit are connected to each other and that a passage of fluid through the first conduit and the second conduit is possible, while in said first position of the control member a passage of said fluid through the third conduit is not possible; or positioning the control member in said second position such that said first conduit and said third conduit are connected to each other and that a passage of said fluid through the first conduit and the third conduit is possible, while in said second position of the control member a passage of said fluid through the second conduit is not possible, wherein the respective conduit through which a passage of said fluid is not possible can be rinsed and vented by the control member. Hence, the respective conduit through which a passage of said fluid is not possible can be prepared for the use as a substitute conduit or additional conduit for connecting to a further circulation system, while in the conduits where the passage of the fluid is still achieved, the fluid circulates and maintains the vital circulation for the patient.

According to a further embodiment of the apparatus, the fluid is a cardioplegic solution for a patient's heart to be operated. Hence, the apparatus can be used for heart surgery.

The invention will be described in the following with respect to preferred embodiments referring to the drawings wherein:

Fig. 1 is a schematic view of the arrangement of conduit systems between a patient and an extracorporeal circulation system;

Fig. 2a is a sectional view of a first embodiment of the apparatus according to the invention;

Fig.2b is a plan view of a control member of the apparatus of the invention as shown in Fig. 2a;

Fig. 2c is a sectional view of the embodiment of Fig. 2a along the line A-A in Fig. 2b; Fig. 3 is a schematic diagram showing an arrangement of the apparatus according to the invention in a conduit system;

Fig. 4a is a sectional view of the first embodiment of the invention with the control member being in a first position;

Fig. 4b is a sectional view of the first embodiment of the invention with the control member being in an intermediate position;

Fig. 4c is a sectional view of the apparatus of the invention with the control member being in a second position;

Fig. 5 is a plan view of the first embodiment of the apparatus according to the invention;

Fig. 6 is a cross-sectional view of the first embodiment of the apparatus according to the invention;

Fig. 7a is a sectional view of a second embodiment of the apparatus according to the invention;

Fig. 7b is a sectional view of a third embodiment of the apparatus according to the invention; Fig. 8 is a schematic diagram illustrating the various steps for preparing the change of a conduit system;

Fig. 9a is a plan view of a fourth embodiment of the apparatus according to the invention; Fig. 9b is a sectional view of the fourth embodiment of the apparatus according to the invention with a control member being in a first position;

Fig. 9c is a sectional view of the fourth embodiment of the apparatus according to the invention with the control member being in a second position;

Fig. 9d is a cross-sectional view of the fourth embodiment of the apparatus according to the invention; Fig. 10a is a sectional view of a fifth embodiment of the apparatus according to the invention with the control member being in a first position; and

Fig. 10b is a sectional view of the fifth embodiment of the apparatus according to the invention with the control member being in a second position.

In the figures, the same parts will have the same reference numerals.

Fig. 1 is a schematic illustration of a first conduit system 41 and a second conduit system 42 connecting a patient 30 with an extracorporeal circulation system 40. A fluid is transported from the patient to the circulation system 40 through the first conduit system 41. After conditioning the fluid in the circulation system 40, the fluid will be transported through the second conduit system 42 towards the patient 30. Hence, a circulation of the fluid is maintained between the first conduit system 41, the circulation system 40, the second conduit system 42 and the patient 30.

In case of depositions in the first conduit system 41 or the second conduit system 42, the flow resistance in the conduit systems will change. In the vicinity of the deposition, the flow velocity will change. An increasing size of the deposition may influence the circulation of the fluid such that the overall flow velocity of the fluid will decrease heavily (in the worst case, the fluid will stop) or is no longer controllable. For maintaining a controlled circulation of the fluid, it is necessary to replace the conduit system in which the deposition occurred by another conduit system which does not have any depositions in its interior. In doing so, both the connection to the patient 30 and the connection to the circulation system 40 must be interrupted. At this time and until the insertion of a new conduit system between the patient 30 and the circulation system 40, the circulation of the fluid is completely stopped. In this situation, high risks for the patient may occur in case that the fluid and the circulation of the fluid have a live-sustaining function. Even if the replacement of the conduit system is well organized, it will always happen that the circulation of the fluid will be interrupted. Another problem in this situation results from the fact that during a continuous circulation of the fluid depositions in the conduit systems usually develop with a slow growth rate (and not suddenly) so that a decrease of the cross section of the conduits due to the depositions will not be detected before a significant change of the flow velocity occurs. As one has to act quickly in such a case, it may happen that the necessary replacement of the conduit system by another conduit system not having depositions may not be performed in an adequate time period.

Furthermore, the circulation of the fluid may be interrupted for other reasons than depositions in the conduit system. E.g., another component of the circulation system may have a defect or a malfunction or the maintenance interval of a component or the whole circulation system is reached. For example, it may be necessary to replace an oxygenator in a circulation system or parts of the oxygenator after a predetermined operation time.

In order to minimize the risk for the patient due to the stopped fluid circulation, the invention uses an apparatus 1 shown in Figures 2a to 2c and Fig. 3.

The apparatus 1 is positioned in one of the conduit systems, preferably in both conduit systems 41 and 42. In Fig. 2a, a cross-sectional view of such an apparatus 1 is shown. The apparatus 1 includes a control member 2 embedded in a housing 6. Three conduits or lines LI, L2 and L3 are provided in the housing 6. The control member 2 includes a hole 3 and two openings 4 wherein the hole 3 extends through the control member from one side to the other. The hole 3 and the conduits LI, L2 and L3 enable the passage of fluid. Fluid may also pass through the openings 4 but there is no direct connection between the openings 4 and the hole 3 in the control member 2. It is not possible that a first fluid which may be provided in the hole 3 mixes into a second fluid which may be provided in the openings 4 within the control member 2.

The control member 2 is arranged in a first position within the device 1 such that one end of the hole 3 is directed towards the conduit LI and that the other end of the hole 3 is directed towards the conduit L2. In case that fluid is provided in the conduit LI, said fluid may pass through the hole 3 and enter into the conduit L2. In this position of the control member 2, fluid cannot flow from conduit LI to conduit L3.

The openings 4 in the control member 2 are arranged symmetrically with respect to the longitudinal axis of the hole 3 in offset positions, and the openings 4 form in the direction towards the edge of the control member 2 an opening end 4a and an opening end 4b, respectively. In the position of the control member 2 shown in Fig. 2a, the opening end 4a is in contact with the housing 6. The opening end 4b is in contact with the conduit L3. Consequently, in the position of the control member 2 shown in Fig. 2a, the transport of a fluid starting at the opening 4 through the opening end 4b towards and through the conduit L3 is enabled. This means that a first fluid may be transported through the conduit LI, the hole 3 to the conduit L2, whereas - independently from the transport of the first fluid - a second fluid may be transported through the opening 4, the opening end 4b and the conduit L3. The housing 6 serves as a support for the control member 2, and the transitional region between the housing 6 and the control member 2 is formed in a fluid-tight manner (not shown in the figure).

The conduits LI, L2 und L3 shown in the embodiment of Fig. 2a are arranged with respect to each other such that the conduits approximately constitute a Y-shaped form. In order to supply fluid to the apparatus 1 and to discharge fluid from the apparatus 1, each conduit LI, L2 and L3 comprises a connection pipe or port 5. The arrows shown in Fig. 2a indicate the flow direction of the fluid which may be transported from the patient via the connection pipe 5 through the conduit LI, the hole 3, the conduit L2 and the connection pipe 5 to a circulation system which is not shown in Fig. 2a.

In Fig. 2b, a plan view of the control member 2 is shown, wherein the dot-and-dash line A, A indicates a cross section, which is shown in Fig. 2c. In Fig. 2c, the extension of the opening 4 including the opening end 4b is shown. In this embodiment, a receiving portion 7 protrudes from the opening 4, and the receiving portion is adapted to receive a pipe, a tube, particularly a flexible tube, or a syringe tube in order to supply fluid to the opening 4 or to discharge fluid from the opening 4. The receiving portion 7 may be closed by a closing cap 8 in order to prevent fluid from entering into the opening 4 or to prevent fluid from leaving the opening 4. Fig. 3 shows a schematic diagram of the first conduit system 41 and the second conduit system 42, wherein in each conduit system an apparatus 1 is interposed. One end of the conduit system 41 is connected to the patient 30, and the other end of the conduit system 41 is connected to the circulation system 40. Analogously, one end of the conduit system 42 is connected to the patient 30, and the other end of the conduit system 42 is connected to the circulation system 40. Each control member 2 of the apparatuses 1 is located in a position such that a fluid may be transported in the direction indicated by arrows 60. Hence, the fluid flows from the first conduit system 41 through the first apparatus 1 to the circulation system 40 and from the circulation system via the second conduit system 42 through the second apparatus 1 back to the patient 30, thus providing a circulation circuit. In case that a deposition is detected in the first conduit system 41 and/or the second conduit system 42, preparations may be made in order to connect a second circulation system 50.

In the arrangement shown in Fig. 3, the fluid flows through the first apparatus 1 which is interposed in the first conduit system 41 via the conduits LI, the hole 3 of the control member 2 and the conduit L2. This position of the control member 2 prevents fluid from flowing through conduit L3. A third conduit system 51 having a connection to the second circulation system 50 is connected to the conduit L3. The circulation path back to the patient has a similar configuration. The fluid flows through the second conduit system 42 to the second apparatus 1, and the control member 2 is in a position such that the fluid flows via the conduit L3, the hole 3 of the control member 2 and the conduit LI towards the patient 30. The position of the control member 2 in the second apparatus 1 prevents fluid from flowing from the second conduit system 42 through conduit L2. A fourth conduit system 52 which connects the conduit L2 to the second circulation system 50, is provided at the conduit L2.

The conduit L3 of the first apparatus 1 which is provided in the third conduit system 51, was flushed/rinsed and vented before connecting to the third conduit system 51, as will be discussed in detail with respect to Fig. 8. If desired, the sterily flushed and vented conduit L3 and the third conduit system 51 may transport fluid from the patient 30 to the second circulation system 50, when the control member 2 is moved from the first position to the second position, as shown in Figures 4a to 4c. For the fluid path back to the patient, similar steps may be performed. The second apparatus 1 which is connected directly to the second conduit system 42 comprises a conduit L2 connected to the fourth conduit system 52. The second conduit system 52 and the conduit L2 are flushed/rinsed and vented and eventually connected to the second circulation system 50, as will be discussed with respect to Fig. 8. By moving the control member 2 from the second position shown in Fig. 3 (compare Fig. 4c) to the first position fluid may be transported from the second circulation system 50 via the fourth conduit system 52, the conduit L2 and the hole 3 of the control member 2 to the conduit LI towards the patient 30.

In case that a deposition is detected in the first conduit system 41 or in the second conduit system 42 or in case that an oxygenator or a part of an oxygenator has to be replaced by a spare part, the second circulation system 50 may be connected to the fluid circulation by just moving one control member 2 from the first position to the second position and the other control member from the second position to the first position. The time interval during which the circulation of the fluid is interrupted, is restricted to the time needed for moving the control member 2 from the first to the second position and vice versa. A realistic time interval is one second or less in order to avoid pressure pulses in the fluid to be generated by the movement of the control member 2.

Even in case that no depositions are detected in one of the conduit systems, the arrangement shown in Fig. 3 may be used. For example, the arrangement may be used in a situation when the first circulation system 40 is a mobile circulation system and the patient 30 is to be connected to a stationary circulation system which would be the second circulation system in Fig. 3. The requirement to prevent the circulation from stopping is fulfilled in this case, too.

Figures 4a to 4c each show cross-sectional views illustrating the apparatus 1 including the control member 2. In Fig. 4a, the control member 2 is in a first position; in Fig. 4b the control member 2 is in an intermediate position, and in Fig. 4c, the control member 2 is in a second position. In the first position of the control member 2, the conduits LI and L2 are connected to each other such that a fluid may be transported from the conduit LI via the hole 3 to conduit L2 or vice versa. One of the openings 4 is connected directly to the conduit L3. In case that the control member 2 is in the intermediate position (see Fig. 4b), the control member 2 acts as a fluid stop member. This means that it is not possible to transport fluid from the conduit LI to conduit L2 or to conduit L3 and from conduit L2 to conduit LI or to conduit L3, respectively. Furthermore, the openings 4 are not connected to any of the conduits LI, L2 and L3 directly. Such an intermediate position is used to reliably prevent fluid from flowing from the conduit L2 to the conduit L3 during the movement of the control member 2 from the first position to the second position. Such an intermediate position may be dangerous for a patient because the fluid is stopped in this position. Therefore, the control member 2 has to be constructed such that it is not possible to position control member 2 in a stable manner in the intermediate position. Rather, it has to be ensured that the control member 2 engages in a stabilized manner from the (instable) intermediate position in both the first position and the second position.

As can be seen from Figures 4a to 4c, the conduit LI has a larger cross section in the transitional region between the control member 2 and the conduit LI than the conduit L2 or the conduit L3 in the transitional region towards the control member 2. This may be advantageous for the fluid flow during the change of the positions of the control member 2. However, it is also possible to construct conduit LI such that said conduit comprises two conduit arms in the transitional region towards the control member 2, wherein said conduit arms extend separately from each other, similarly to conduits L2 and L3, and wherein said conduit arms have the same cross section as the conduits L2 and L3. This configuration has advantages because it avoids zones of nearly resting and hardly or non-moving fluid in the transitional region between the control member and the conduit LI. Such "dead zones" are particularly undesired when the fluid is blood.

Fig. 5 is a plan view of an embodiment of the apparatus 1 according to the invention. In Fig. 5, a handle 9 is shown, which is used for moving the control member 2 from the first position to the second position and vice versa. The housing 6 has a surface comprising recesses in the form of circular arcs. These recesses are formed such that the openings 4 of the corresponding receiving portion 7 are accessible in both the first position of the control member 2 and the second position of the control member 2 such that a fluid may be supplied to the apparatus 1 or discharged from the apparatus 1. The position of the handle 9 is only an example, and both the form of the handle 9 and the connection of the handle 9 to the control member 2 are shown by way of example and may have any other forms. However, the access to the openings 4 and the receiving portions 7 has to be sufficiently large such that fluid can be supplied to the apparatus 1 or discharged from the apparatus 1. In Fig. 6, a cross-sectional view of the apparatus 1 is shown. The control member 2 is positioned between an upper housing portion 6a and a lower housing portion 6b. The conduits LI, L2 and L3 extend substantially in a central portion in the apparatus 1 between the upper housing portion 6a and the lower housing portion 6b. The handle 9 is positioned outside the housing 6 and connected to the control member 2 via a connecting element. The receiving portion 7 is positioned within the housing upper portion 6a, but it may also protrude from the upper housing portion 6a in order to enable a better access to the receiving portion. The upper housing portion 6a and the lower housing portion 6b may be screwed together or formed such that the housing portions form a sliding bearing for the control member 2.

The assembly shown in Fig. 3 comprises two distinct apparatuses 1, wherein each apparatus is to be actuated separately in order to move the respective control member 2 from one position to the other position. In principle, when connecting a second circulation system to the fluid circulation, both the fluid supply and the fluid discharge have to be ensured. Hence, the control member 2 which controls the fluid supply and the control member 2 which controls the fluid discharge have to be actuated simultaneously. Therefore, it is advisable to integrate both control members in one housing. In Fig. 7a, a cross-sectional view of such a device including two control members is shown. The first control member 2a connects the conduit LI to the conduits L2 and L3, and the second control member 2b connects the conduits L4 to the conduits L5 or L6. In the embodiment shown in Fig. 7a, the receiving portion 7 of each control member is positioned such that a pipe, a flexible tube or a syringe tube may be connected from outside to the respective receiving portion 7. In order to enable the simultaneous actuation of both control members 2a, 2b, the handle 9 is formed such that it connects both control members 2a, 2b with each other by an arc which extends around the housing 6. In this configuration, both control members 2a, 2b are moved from the first position to the second position or from the second position to the first position. This corresponds to a situation in the assembly of Fig. 3, where the second conduit system 42 is connected to the conduit L2 and the fourth conduit system 52 is connected to the conduit L3 (not shown).

In Fig. 7b, a cross-sectional view of a further embodiment of the apparatus 1 according to the invention is shown. This embodiment is similar to the embodiment shown in Fig. 7a, but differs in the number of control members. The control member 2 shown in Fig. 7b is formed such that it enables the connection of both conduit LI to conduits L2 or L3 and conduit L4 to conduits L5 or L6. Similarly to the embodiment of Fig. 7a, just one single handle 9 is needed in order to change simultaneously the fluid direction from the first conduit system and the second conduit system to the third conduit system and the fourth conduit system. In the embodiment shown in Fig. 7b, the number of components is less than the number of components used in the embodiment shown in Fig. 7a. Nevertheless, the same level of security is achieved when changing the fluid direction.

In Fig. 8, images are shown which illustrate successive steps and conditions which are preferably performed during the change from one conduit system to another conduit system. In image 1, the device is shown with the control member 2 being in a first position connecting the conduit LI to conduit L2. In this position, the opening 4 is connected to the conduit L3. A first connection pipe 5 which may be a flexible tube is connected to the conduit L3. While fluid is circulating through the conduit LI, the hole 3 and the conduit L2 (not shown), a rinse solution 10 is supplied via the opening 4 shown in image 1, the solution flowing from the opening 4 into the conduit L3 and from the conduit L3 into the first connection pipe 5. In case that the first connection pipe 5 is pinched off by a clamp 11 at a position relatively far from the apparatus 1, the rinse solution 10 accumulates in the cavity formed by the opening 4, the conduit L3 and the first connection pipe 5. Rinse solution 10 accumulated in the section between the clamp 11 and the distal end of the connection pipe 5 may be drained off by positioning said section such that it hangs downward so that the rinse solution 10 flows into a container 12. After the rinse solution 10 has been drained off, the connection pipe 5 will be cut off by a knife 13, see image 2 and image 3 of Fig. 8. At the cut-off end of the connection pipe 5, a connection pipe adapter 14 is mounted, see image 4 in Fig. 8. A second connection pipe 15 is connected to the adapter, see image 5 in Fig. 8. The second connection pipe 15 is provided for establishing a connection to the second circulation system 50, see image 6 in Fig. 8.

When the second connection pipe 15 is coupled to the second circulation system 50, fluid is supplied from the circulation system 50 via the second connection pipe 15 towards the first connection pipe 5, see image 7 in Fig. 8. The fluid 16 from the second circulation system 50 flows to the clamp 11, which serves as a stopper for stopping the fluid transport. In case that clamp 11 at the pinch-off position in the first connection pipe 5 is opened, the fluid 16 may flow from the second circulation system 50 via the second connection pipe 15, the first connection pipe 5 and the conduit L3 towards the opening 4. If the rinse solution 10 does not mix into the fluid, the rinse solution 10 may be discharged from the opening 4 of the control member 2 via a conduit 17 so that the solution will be collected in a container 18. If the fluid 16 mixes into the rinse solution 10 and if this mixing is desired, a conduit 17 and a container 18 are not necessary. Alternatively, the rinse solution 10 stored in the opening 4, the conduit L3 and the first connection pipe 5 may be sucked off by sucking means via the opening 4, for example by using a syringe. As a consequence, this portion is rinsed and vented and may be filled with the fluid 16 thereafter, as shown in image 8 of Fig. 8. When the second connection pipe 15, the first connection pipe 5 and the conduit L3 are filled with fluid, the control member 2 is moved from the first position to the second position so that the conduit LI and the conduit L3 are connected to each other, see image 9 in Fig. 8.

The device 1 shown in Fig. 8 comprises conduits LI, L2 and L3. It is obvious for the skilled person that the steps described above may also be performed in a device which additionally has the conduits L4, L5 and L6, see Fig. 7b.

Figures 9a to 9d show another embodiment of the apparatus according to the invention. Fig.

9a is a plan view and Fig. 9b is a cross-sectional view of the apparatus 1. Contrary to the embodiment shown in Fig. 2, the control member 2 has an elongated form and is not a circular-shaped body. In this embodiment, the control member 2 also has a hole 3 which connects the conduit LI to the conduit L2 in the first position of the control member 2.

Furthermore, the control member 2 includes two openings 4 wherein one opening is connected to the conduit L3 when the control member 2 is located in the first position. The other opening 4 is not connected to a conduit when the control member 2 is in the first position.

The conduits LI, L2 and L3 are arranged such that their openings at the edge of the housing are only located on one side. This feature is different from the embodiment shown in Fig. 2 where the opening of the conduit LI is located on one side of the housing and the openings of the conduits L2 and L3 are located on the opposite side of the housing. Locating the openings of the conduits LI, L2 and L3 only on one side of the housing may have advantages, particularly in cases of restricted space and/or in case that the access to the other side of the housing is not possible or difficult, e.g. when the housing is mounted in another device.

In the embodiment shown in Figures 9a to 9d, the control member is moved from the first position to the second position by a linear movement. To do so, the handle 9 may be used in order to move the control member 2. In figure 9c, a sectional view of the apparatus is shown wherein the control member 2 is located in the second position. In this position, the hole 3 connects the conduit LI to the conduit L3, and the opening 4 of the control member 2 is connected to the conduit L2. The other opening 4 of the control member 2 which was connected to the conduit L3 in the position of the control member 2 is not connected to a conduit in the second position of the control member 2. In figure 9d, a cross-sectional view of the apparatus 1 along the dot-and-dash line A-A of figure 9c is shown. The connection between the opening 4 and the conduit L2 is established by the control member 2 and the geometry of this connection is such that only few depositions and turbulences occur in the fluid flowing therethrough.

In figures 10a and 10b, a further embodiment of the apparatus according to the invention is shown. In the first position of the control member 2 (see figure 10a), the conduits LI and L2 are connected with each other whereas the conduit L3 is blocked by the control member 2. In the first position of the control member 2, the conduit L3 may be connected to one of the openings 4 so that the conduit may be rinsed and vented. The control member 2 may be rotated from the first position to the second position, see figure 10b. This rotation occurs around the rotational axis A wherein in the second position the conduit LI is connected to the conduit L3. Contrary to the embodiments described above, in the control member 2 of the embodiment shown in figure 10a, 10b, there is no need for a hole 3 in order to connect the conduit LI to L2 or LI to L3. In case that there is no need for an intermediate position (see figure 4b) and for an accurate separation between two separated fluid circulations, the hole 3 may be omitted. It is important in this embodiment that the control member 2 is locked in the first position and in the second position to prevent the control member 2 from moving from one position to the other position during an inhomogeneous flow of fluid. List of reference numerals

Reference numeral designation

1 apparatus

2 control member

2a first control member

2b second control member

3 hole

4 opening

4a first opening end

4b second opening end

5 first connection pipe

6 housing

6a upper housing portion

6b lower housing portion

7 receiving portion

8 closing cap

9 handle

10 rinse solution

11 clamp

12 container

13 knife

14 connection pipe adapter

15 second connection pipe

16 fluid

17 conduit

18 container

30 patient

40 first circulation system

41 first conduit system

42 second conduit system Reference numeral designation

50 second circulation system

51 third conduit system 52 fourth conduit system

60 arrow

A rotational axis

LI first conduit L2 second conduit

L3 third conduit

L4 fourth conduit

L5 fifth conduit

L6 sixth conduit

Claims

1. An apparatus for controlling a fluid of extracorporeal circulation systems, comprising: - at least three conduits for transporting said fluid therethrough and - a control member which connects in a first position a first conduit and a second conduit of said at least three conduits with each other such that a passage of fluid through said first conduit and said second conduit is possible, while the passage of said fluid through a third conduit of said at least three conduits is not possible, and wherein in a second position the control member connects said first conduit to said third conduit such that a passage of said fluid through said first conduit and said third conduit is possible, while the passage of said fluid through said second conduit is not possible, wherein the respective conduit through which a passage of said fluid is not possible can be rinsed or vented via the control member.

2. The apparatus according to claim 1, wherein the control member comprises a hole for transporting said fluid therethrough.

3. The apparatus according to one of claims 1 or 2, wherein the control member comprises at least one opening for supplying a rinse solution to one of the conduits which can be rinsed and vented or for discharging said rinse solution from one of the conduits which can be rinsed and vented.

4. The apparatus according to one of claims 1 to 3, wherein a connection pipe can be connected to each conduit.

5. The apparatus according to claim 4, wherein the connection pipe is a tube.

6. The apparatus according to claim 4, wherein the connection pipe is a flexible tube.

7. The apparatus according to one of claims 4 to 6, wherein the connection pipe can be plugged onto the conduit.

8. The apparatus according to one of claims 4 to 6, wherein the connection pipe can be screwed onto the conduit.

9. The apparatus according to one of claims 1 to 8, wherein each conduit is closable.

10. The apparatus according to one of claims 4 to 9, wherein at least one connection pipe is closable.

11. The apparatus according to one of claims 4 to 10, wherein at least one connection pipe is fillable with a rinse solution.

12. The apparatus according to one of claims 1 to 11, wherein said at least three conduits constitute a Y-shaped form.

13. The apparatus according to claim 12, wherein the control member is movable by a rotational movement from said first position to said second position and from said second position to said first position.

14. The apparatus according to one of claims 1 to 11, wherein said at least three conduits are arranged parallel with respect to each other.

15. The apparatus according to claim 14, wherein the control member is movable by a linear movement from the first position to the second position.

16. The apparatus according to one of claims 1 to 15, wherein the apparatus is adapted to be connected to a patient via a fluid pumping system.

17. The apparatus according to claim 16, wherein the fluid pumping system is part of a ventricular assisting device (NAD).

18. The apparatus according to claim 17, wherein the fluid pumping system is useable for assisting the left side of the heart (LNAD) and/or for assisting the right side of the heart (RVAD) and/or for assisting both sides of the heart (BIN AD).

19. The apparatus according to one of claims 16 to 18, wherein the fluid pumping system is part of a heart-lung-machine.

20. The apparatus according to one of claims 1 to 19, wherein - the control member connects in the first position a fourth conduit and a fifth conduit with each other such that a passage of said fluid through said fourth conduit and said fifth conduit is possible, while a passage of said fluid through a sixth conduit is not possible, and - the control member connects in the second position said fourth conduit to said sixth conduit such that a passage of said fluid through said fourth and said sixth conduit is possible, while a passage of said fluid through said fifth conduit is not possible, - wherein the respective conduit through which a passage of said fluid is not possible can be rinsed and vented via the control member.

21. The apparatus according to claim 20, wherein said first conduit, said second conduit and said third conduit are adapted for the passage of blood enriched with oxygen from a fluid pumping system towards the patient and wherein said fourth conduit, said fifth conduit and said sixth conduit are adapted for the passage of venous blood from the patient to said fluid pumping system.

22. The apparatus according to one of claims 1 to 21, wherein said conduit or conduits which can be rinsed and vented are connectable to an additional fluid pumping system.

23. The apparatus according to one of claims 16 to 22, wherein one of said fluid pumping systems is a mobile fluid pumping system.

24. The apparatus according to one of claims 1 to 23, wherein the control member does not connect any of the conduits with each other in a third position.

25. The apparatus according to one of claims 21 to 24 for use in a in vitro circulation system which enables a change from the first fluid pumping system to the second fluid pumping system and a change from the second fluid pumping system to the first fluid pumping system during a continuous operation.

26. The apparatus according to one of claims 1 to 25, wherein the apparatus is substantially made out of plastic or glass.

27. The apparatus according to one of claims 1 to 26, wherein the fluid is a cardioplegic solution for a heart of a patient to be operated.

28. A method for controlling a fluid of extracorporeal circulation systems by using the apparatus according to one of claims 1 to 27, wherein the method comprises the following steps: - positioning the control member in a first position such that said first conduit and said second conduit are connected with each other and that a passage of said fluid through said first conduit and said second conduit is possible, while in said first position of the control member the passage of said fluid through said third conduit is not possible, - or positioning the control member in said second position such that said first conduit and said third conduit are connected with each other and that a passage of said fluid through said first conduit and said third conduit is possible, while in said second position of the control member a passage of said fluid through said second conduit is not possible, wherein the respective conduit through which the passage of said fluid is not possible is rinsed and vented via the control member.