Abstract:
The invention pertains to a cassette ( 2 ) comprising a product conveying path ( 1, 1   a,    1   b ) and a shut-off device ( 19   a,    19   b ) integrated into the cassette for interrupting a product flow. The shut-off device is arranged at a rim of the cassette such that the shut-off device ( 19   a,    19   b ) can be directly operated manually and/or mechanically. The product-conveying path ( 1, 1   a,    1   b ) leads through the shut-off device ( 19   a,    19   b ). The cassette consists of a lower part ( 5 ) and an upper part ( 7 ) which are connectable to each other by connecting means ( 9, 11, 13, 15 ).

Description:
TECHNICAL FIELD 
       [0001]    The invention relates to a cassette used as cover for accommodating blood bags for a cartridge of a centrifuge for separating blood components, and a system component insertable into such a centrifuge in cooperation with the cassette. 
       BRIEF DESCRIPTION OF RELATED ART 
       [0002]    In transfusion medicine, the so-called blood component therapy has established itself since the beginning of the nineties. This means that, instead of a whole blood conserve, only those blood components required by the individual patient are administered to said patient. This separate administering of the individual blood components makes it possible that one single blood conserve is sufficient to optimally help an average of 1.8 patients. 
         [0003]    The essential blood components are
       the red blood cells in the so-called erythrocyte concentrate, which are transfused in order to maintain the oxygen supply after severe loss of blood,   the blood platelets in the thrombocyte concentrate, which are administered in cases of coagulation disturbances (haemophilia), and   the blood plasma, which is administered in cases of coagulation disturbances and volume deficits.       
 
         [0007]    Apart therefrom, blood plasma is an essential basic component for the production of many medicaments. 
         [0008]    The separation of the individual blood components, which is defined as cell separation/isolation, is known to be effected by treating the blood in a centrifuge. By means of centrifuging, the individual blood components are separated from each other, and can then be separately filled into the respective containers for further use. 
         [0009]    Documents DE 10 2007 000 308 A1, DE 10 2007 000 309 A1 and DE 10 2007 000 310 A1 already reveal a cartridge for use in a centrifuge for separating blood components and a respective centrifuge as well as a respective method. According to these documents, a cartridge comprises an intermediate wall and a cover. The intermediate wall separates a blood bag area disposed radially inside from a product area disposed radially outside. In an installation position of the cartridge, the cover is located above the blood bag area. The cover is connected to the intermediate wall pivotally at one point, and detachably at a second point. In this way, the blood bag area is freely accessible by a lateral turning away of the cover. For loading the cartridge with a blood bag, the cover is opened, a blood bag and a product bag are inserted into the respective chambers, and a connecting tube is inserted along a product conveying path. Moreover, photosensitive sensors are arranged along the product conveying path and are used to establish the composition of the product while the product is obtained; and, when a specific composition is reached, measures are taken for terminating the obtaining of the product. However, loading of the cartridge may only be effected manually, which renders it time- and cost-consuming. Besides, there is the possibility that the product is destroyed upon a faulty insertion of the connecting tube, since the sensors do not react timely. 
         [0010]    Therefore, the known means need to be improved such that, on the one hand, faulty loading is avoided and, on the other hand, time is saved. 
       BRIEF SUMMARY 
       [0011]    According to the invention, a cassette comprising a product conveying path and a shut-off device for interrupting a product flow are provided. The shut-off device is integrated into the cassette, and it is arranged at a rim of the cassette such that the shut-off device can be directly operated manually and/or mechanically. The product-conveying path leads through the shut-off device. The cassette comprises a lower part and an upper part which are connected to each other by snap elements or other means. Other means in terms of the invention may e.g. be screw joints and/or rivet joints, or bonded joints. 
         [0012]    Preferably, the shut-off device can be provided in the form of two tube clamps that can be operated separately from each other. 
         [0013]    Moreover, the shut-off device can be integrated either only into the lower part, or only into the upper part. 
         [0014]    Preferably, the product-conveying path can be provided in the form of a passage, and a tube can be disposed in the product-conveying path. This is advantageous insofar as a tube laid along the product-conveying path remains reliably positioned, since it is excluded that the tube drops out of the product-conveying path when the cassette is handled. When assembling the cassette, the tube is inserted into the product-conveying path before the lower part and the upper part of the cassette are connected to each other. 
         [0015]    Preferably, the cassette can comprise connecting means for being connected to a cartridge for accommodating the cassette, said cartridge being adapted to be accommodated in the centrifuge or in the system component arranged in the centrifuge. This constitutes an advantage insofar as, besides the tube, the cassette may also comprise a blood bag attached thereto and a product bag also attached thereto; compared to the prior art, this allows a quicker and more reliable loading of the cartridge. 
         [0016]    Preferably, the cassette can comprise a positioning means that is engageable with a counter-piece on a centrifuge or a system component arranged in a centrifuge such that a section of the product-conveying path is aligned with a section of the centrifuge or the system component arranged in the centrifuge. In particular, the section of the product-conveying path and/or tube arranged directly adjacent to the positioning means can be exactly positioned to be directly adjacent to the counter piece. 
         [0017]    This is advantageous because the system component may include sensors preferably arranged at the counter piece, and adapted to detect a composition of the product in the product-conveying path and/or tube. Depending on the composition of the product, the sensors can then output signals to a microprocessor monitoring and controlling further processes. In particular, due to the positioning means, it is ensured that an axis of the sensors substantially intersects a central axis of the product conveying path at a right angle. 
         [0018]    The cassette according to the invention can be inserted into the system component. The system component is provided for arrangement in a centrifuge having a rotor rotatable around a hub for separating blood components. The system component can be integrated into the rotor, or can be freely inserted or removed from the same. The system component comprises an operating means used for operating a shut-off device of the cassette. 
         [0019]    Preferably, the operating means can be provided in the form of an arrangement of levers. The operating means can have a centrally arranged lever whose ends can be directly or indirectly operated individually—i.e. independently of each other. If the end is operated directly, it has a longer stroke than if it is operated indirectly. 
         [0020]    Besides, the operating means can have a short lever designed to act, when operated, on an opening means as well as on a closing means of the shut-off device of the cassette. Thus, the opening as well as the closing of the shut-off device is advantageously possible by the operation of the short lever. 
         [0021]    To this end, the short lever is advantageously provided in the form of an L-shape and is rotatably supported. In particular, the short lever can be supported such that, when operated, one leg acts on the closing means of the shut-off device via the long end of the long lever, and the second leg of the short lever simultaneously acts on the opening means. This is particularly possible when the one short leg is supported such that one end of the long lever is disposed between the opening means of the shut-off device and the leg of the short lever. 
         [0022]    When the short lever is operated, it then turns around the point on which it is supported. The one leg acts on the end of the long lever, said end being displaced by this effect in the direction of the closing means of the shut-off device. Simultaneously, the second leg of the short lever acts on the opening means of the shut-off device. 
         [0023]    If the shut-off device is provided in the form of a tube clamp which is in a closed state, it is opened by the operation of the short lever. However, since the end of the long lever is simultaneously moved in the direction of the opening means preferably designed as an opening arm, the tube clamp does not burst open abruptly, but is opened slowly and evenly. That is, the stroke of the end of the long lever is shorter with this indirect operation than with the direct operation. 
         [0024]    Preferably, the operating means can comprise a first piston operable manually and/or pneumatically and/or hydraulically and/or electrically. For closing the shut-off device, said piston directly acts on one of the ends of the long lever. 
         [0025]    Besides, the system component can comprise a second piston operable manually and/or pneumatically and/or hydraulically and/or electrically, which, for opening the shut-off device, directly acts on a leg of the short lever and, via said one leg, indirectly on one of the ends of the long lever. Since the short lever is advantageously provided in an L-shape and rotatably, the second leg of the short lever directly acts on the opening means of the shut-off device. 
         [0026]    Preferably, the cassette and the system component can be used in a centrifuge having a rotor rotatable around a hub for separating blood components. The system component is accommodated in the rotor, or integrated into the same. Moreover, a cartridge can be incorporated into the system component, and this cartridge can be provided with a cassette loaded with a blood bag and a product bag. The cassette is used as cover for a blood bag area of the cartridge. 
         [0027]    The use of a cassette according to the invention and the system component according to the invention allows to obtain one or also plural blood products, such as plasma, erythrocytes, or thrombocytes. This may be obtained particularly in that a microprocessor can be provided in the system component to be used for controlling and monitoring the product extraction process. 
         [0028]    Then, by means of the microprocessor, particularly the detection results of the sensors can be processed and the operations of the shut-off devices can be carried out accordingly. Advantageously, the microprocessor in the system component can furthermore be connected to another microprocessor accommodated in the rotor of the centrifuge, said microprocessor being adapted to carry out the control and the monitoring of the entire product extraction process. 
         [0029]    As mentioned before, cassettes with the already inserted tube and two or more bags (one blood bag and at least one product bag) attached to the tube can be supplied to a user in the form of a kit. Thus, after a blood collecting process, the cassette comprising the tube and the bags can be inserted into a system component of a centrifuge, or directly into the centrifuge to perform a centrifugation process in which the blood in the one bag is separated and at least one of the separated blood components is transferred into the second bag. 
         [0030]    After this centrifugation process has been completed, it is merely necessary to replace the cassette present in the centrifuge by a new one and to subject the old cassette to further processing. In this respect it is noted that, in general, any number of cassettes can be subjected to the centrifugation process. Preferably a number of six cassettes is processed simultaneously in the centrifuge. 
         [0031]    Since the tubes and bags are replaced together with their related cassette, a remarkable reduction of dead time is achieved. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0032]    Further advantages of the invention can be seen from the description of a currently preferred embodiment and the Figures attached. Referring to the Figures, 
           [0033]      FIG. 1  shows a top view of a lower part of a cassette according to the invention; 
           [0034]      FIG. 2  shows a sectional view along a line II-II in  FIG. 1 ; 
           [0035]      FIGS. 3   a  and  3   b  show a top view and a view of a detail III from  FIG. 1 , respectively; 
           [0036]      FIG. 4  shows a sectional view along a line IV-IV in  FIG. 1 , 
           [0037]      FIG. 5  shows a top view of an upper part of a cassette according to the invention; 
           [0038]      FIG. 6  shows a sectional view along a line VI-VI in  FIG. 5 ; 
           [0039]      FIG. 7  shows a sectional view along a line VII-VII in  FIG. 5 ; 
           [0040]      FIG. 8  shows a view of a cassette according to the invention, said cassette being provided in a system component according to the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0041]    A currently preferred embodiment of the invention is described by means of  FIGS. 1 to 8 . 
         [0042]    A cassette  2  according to the embodiment is composed of a lower part  5  and an upper part  7 , which are connected to each other by means of snap elements  9  and  13 , and  11  and  15 , respectively. The upper part is made of a transparent material. Besides, as can be seen from the Figures, the cassette  2  approximately shows the form of a rectangle having two arms  35   a ,  35   b.    
         [0043]    The lower part  5  as well as the upper part  7  of the cassette  2  comprises a window  17  in a central area of the rectangle. Moreover, in the upper part  7 , two bars  3   a ,  3   b  are formed in the window  17 , and are used as positioning means according to the invention. The bars  3   a ,  3   b  extend along a partial section of a product-conveying path  1 . 
         [0044]    In the lower part  5 , a channel-type passage  1  is formed as product-conveying path  1  according to the invention. The passage  1  is divided into two sections  1   a  and  1   b . At an edge of the lower part  5  opposite the arms  35   a ,  35   b , two tube clamps  19   a ,  19   b  are integrated into the lower part  5 . 
         [0045]    A tube (not shown in the Figures) provided with a blood bag, a filter and a product bag is laid in the product-conveying path  1  such that the tube is conducted from the blood bag disposed between the arms  35   a ,  35   b  to the first section  1   a , along the bar  3   a , through the tube clamp  19   a  arranged in the first section  1   a  further to the arm  35   a . The tube then emerges from the arm  35   a , leads to the filter, and enters the second section  1   b  of the passage  1  via the second arm  35   b . Then, the tube is led along the bar  3   b , through the tube clamp  19   b  and again the arm  35   b , in order to emerge from the same towards the product bag. 
         [0046]    At each of its arms  35   a ,  35   b , the cassette  2  comprises a projection  21   a ,  21   b  disposed inside, which is used to detachably fix the cassette to a non-represented cartridge similar to the one in documents DE 10 2007 000 308 A1, DE 10 2007 000 309 A1 and DE 10 2007 000 310 A1. The blood bag, the filter and the product bag are then accommodated in appropriate chambers of the cartridge. The cassette  2  replaces a cover in the said applications. 
         [0047]    Together with the cassette  2 , the loaded cartridge is inserted into a system component  4  that is arranged in a centrifuge. An elevation  25  in which two grooves are formed is provided in a section of the system component  4 . Photosensitive sensors  23   a ,  23   b  are inserted into the inner walls of each groove. 
         [0048]    If the cassette  2  is disposed in the system component  4 , the elevation  25  is engaged in a form-fit connection with the window  17 , and the bars  3   a  and  3   b  with the grooves formed in the elevation  25 . The sections of the tube extending along the bars  3   a ,  3   b  are disposed directly below the bars  3   a ,  3   b , whereby the contents of the tube can be exactly registered by the photosensitive sensors  23   a ,  23   b . The first photosensitive sensor  23   a  is assigned to the first section  1   a  of the product-conveying path  1 , whereas the second photosensitive sensor  23   b  is assigned to the second section  1   b  of the product-conveying path  1 . The optical axes of the photosensitive sensors  23   a  and  23   b  substantially intersect the central axis of the product conveying path (the tube) at a right angle. 
         [0049]    Since the tube does not have to be inserted into the cassette  2  any more, but the cassette is already delivered together with the readily laid tube including blood bag, filter and product bag, a faulty insertion of the tube or a displacement of the tube that would lead to a faulty registration by the sensors can be reliably excluded. 
         [0050]    Thus, it is possible, due to the interaction of the cassette according to the invention with the system component, to obtain a blood product by means of the method disclosed in document DE 10 2007 000 309 A. 
         [0051]    According to the embodiment, the rotor of the centrifuge is designed for six system components  4  having one cartridge each. After all cartridges loaded with cassettes  2  have been inserted, the centrifuge is started. By means of the centrifugal force, the desired separation of the blood components is effected. Since the “buffy coat” diluted by an additive solution is in the blood bag, the lighter components thereof will remain radially inside, whereas its heavier components, i.e. the red blood cells, collect outside. 
         [0052]    In order to transport the desired blood component—according to the embodiment, these are the platelets (thrombocytes)—in high quality, i.e. without the admixture of other blood cells, from the blood bag, the separation of the components will be followed by a slight pressure being applied onto the blood bag by means of a pressure pad, so that, after the previously closed tube clamps  19   a ,  19   b  have been opened, the solution rich in platelets begins to rise into the tube disposed in the passage  1 . The solution rich in platelets is led through the tube into the filter designed as a leukocyte filter, and is further conducted therethrough. 
         [0053]    In the leukocyte filter, the undesired leukocytes, i.e. the white blood cells, are removed. Due to the arrangement of the tube with the filter, the filtration is effected against the centrifugal force. Thus, heavier blood components, such as unintentionally transported red blood cells, are trapped in a filter-inlet chamber positioned radially outside. 
         [0054]    After having passed the leukocyte filter, the solution rich in platelets continues flowing through the tube laid in the second section  1   b  of the passage  1  into a product bag, in which it is collected. Preferably, the product bag is already formed as final storage bag for the product. 
         [0055]    In order to remove any air that might be present in the filter, the flow speed is kept low for a certain volume quantity at the beginning of the product transfer, thereby enabling the filter to fill with the blood product reliably and completely. After the transfer of this specific volume quantity, the conveying speed for a specific second volume quantity is increased by means of an appropriate control of the pressure pad. While this second volume is transported, there is hardly any risk that red blood cells contaminate the blood product (here: the thrombocyte concentrate). Should this nevertheless happen, this small number of red blood cells are collected in the lower and outer area of the filter, due to the tube being guided from radially outside and below into the filter, and due to the effect of the centrifugal force. 
         [0056]    After the second volume has been transferred, the first photosensor  23   a  is activated and the flow speed of the blood product in the tube is reduced. 
         [0057]    When the first photosensor  23   a  detects a predetermined proportion of red blood cells in the thrombocyte-rich solution, it outputs a signal by means of which the flow speed is again reduced. Furthermore, the second photosensor  23   b  disposed behind the filter is activated. 
         [0058]    During this phase, also a rather large number of red blood cells can enter the filter and even pass therethrough until the second photosensor  23   b  detects a predetermined proportion of red blood cells in the blood product and outputs a signal for terminating the cell separation process. By this signal, the tube clamps  19   a ,  19   b  are closed by operation of the ends  29   a ,  29   b  of a long lever  29  by means of pistons  31   a ,  31   b , so that the red blood cells in the filter are reliably separated from the thrombocyte concentrate in the product bag. 
         [0059]    As an alternative to the termination by the second photosensor  23   b , the cell separation process can also be terminated after a certain period of time has elapsed after the activation of the second photosensor  23   b.    
         [0060]    In the embodiment, altogether six cartridges are provided in the centrifuge. The above-described control of the cell separation process in a cartridge  1  by means of a pressure pad, the opening and closing of the tube clamps  19   a ,  19   b , and the process control by means of the two photosensors  23   a ,  23   b  enables a continued cell separation in the cartridges of the other system components, since the described process control takes place individually for every combination of cartridge and system component. 
         [0061]    The control of the process is effected by a microprocessor provided in the system component, said microprocessor processing the detection/registration results of the sensors  23   a ,  23   b  and accordingly controlling the opening and closing of the tube clamps  19   a ,  19   b  by operating the levers  31   a ,  31   b  and  33   a ,  33   b , respectively. Besides, the microprocessor is connected to a microprocessor arranged in the hub of the rotor of the centrifuge for controlling the centrifuge and monitoring the microprocessors in the individual system components. 
         [0062]    When the above-mentioned process is carried out, a precise operation of the tube clamps  19   a ,  19   b  is required for ensuring an optimum yield while simultaneously avoiding a contamination of the product. For operating the tube clamps  19   a  and  19   b  integrated in the lower part  5  of the cassette  2 , the invention provides, in the system component, an arrangement having a centrally arranged long lever  29  and L-shaped, short levers  27   a ,  27   b  arranged at the two ends  29   a  and  29   b  of the long lever  29 . The ends  29   a ,  29   b  of the long lever are disposed between a leg of the short lever  27   a ,  27   b  and a closing arm  191  of the tube clamps  19   a  and  19   b , respectively. 
         [0063]    At its central section, the long lever  29  is fixed to the system component  4 . The short levers  27   a ,  27   b  are pivotally supported around the intersection of the two legs of the “L”. The entire lever arrangement is disposed along the edge of the cassette  2 , on which the tube clamps  19   a ,  19   b  are arranged when the cassette is inserted in the system component. 
         [0064]    Pistons  31   a ,  31   b ,  33   a ,  33   b , which are suitably arranged in the system component  4 , are used for operating the levers  27   a ,  27   b  and  29 . The pistons  31   a ,  31   b  act directly on the respective end  29   a ,  29   b  of the long lever. The pistons  33   a ,  33   b  act directly on a leg of the short levers  27   a  and  27   b , respectively, said leg being disposed between the pistons  33   a  and  33   b  and the respective ends  29   a ,  29   b  of the long lever  29 . 
         [0065]    Since the ends  29   a ,  29   b  of the long lever  29  are disposed directly opposite the closing arm  191  of the tube clamps  19   a  and  19   b  when the cassette is inserted, an operation of the piston  31   a  or  31   b  leads to the closing of the respective tube clamp  19   a  or  19   b . Since, in turn, an operation of the pistons  33   a ,  33   b  acts on the one leg of the rotatably supported, short levers  27   a  and  27   b , respectively, this operation leads to a twisting of the levers  27   a  and  27   b , respectively. The leg disposed between the pistons  33   a  and  33   b  acts on the end  29   a  or  29   b  of the long lever  29 , whereas the other leg of the short lever  27   a  or  27   b  acts on an opening arm  192  of the tube clamp  19   a  or  19   b , thereby opening the same. The indirect operation of the ends  29   a ,  29   b  of the long lever serves to exclude that the tube clamp bursts open too suddenly or too wide, so that problems e.g. due to the tube clamps getting jammed can be avoided. 
         [0066]    The invention has been described by means of a currently preferred embodiment. However, it is not restricted thereto in any way, but only defined by the scope of the claims attached.