Abstract:
The present invention relates to extracorporeal blood treatment devices and methods and devices for conserving extracorporeal blood treatment devices. In accordance with the present invention, an antifreeze agent in introduced only into that part of the dialysis liquid system of the blood treatment device that includes the volume lying upstream of a sterile filter with which sterile substituate is recovered from the dialysis liquid. Accordingly, that part of the dialysis liquid system that includes the volume lying downstream of the sterile filter is not filled with an antifreeze agent. The present invention makes it possible, after removal of the sterile filter, to easily and safely separate a substituate segment from the rest of the dialysis liquid system and drain off liquid located in the substituate segment.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application No. 61/640,037, filed on Apr. 30, 2012, and German Patent Application No. 10 2012 008 551.6, filed on Apr. 30, 2012. 
     
    
     FIELD OF INVENTION 
       [0002]    The present invention relates to a device for carrying out a method for conserving an extracorporeal blood treatment device, and to a method for conserving an extracorporeal blood treatment device. The present invention further relates to an extracorporeal blood treatment device with a device for carrying out a method for conserving the blood treatment device. 
       BACKGROUND OF INVENTION 
       [0003]    The known dialysis devices have an extracorporeal blood circuit and a dialysis liquid system. The dialysis liquid system of the known dialysis devices comprises a dialysis liquid delivery line, which leads from a dialysis liquid source to the dialysis liquid chamber of a dialyser, and a dialysis liquid removal line, which leads from the dialysis liquid chamber of the dialyser to an outflow. While the dialysis liquid flows through the dialysis liquid chamber of the dialyser, substance transport takes place across the membrane of the dialyser into the blood chamber. In what is called hemo(dia)filtration, some of the liquid drawn off through the membrane of the dialyser is replaced by a sterile replacement liquid (substituate), which is delivered to the extracorporeal blood circuit either upstream or downstream of the dialyser. The delivery of the substituate takes place via a substituate line, which leads to the extracorporeal blood circuit. 
         [0004]    It has been found in practice that the substituate can be recovered in a sterile state from the dialysis liquid online during the blood treatment. 
         [0005]    Dialysis devices are known in which the substituate is recovered from the dialysis liquid during the dialysis treatment (online). In order to ensure that the substituate recovered online is sterile and free of pyrogens, the dialysis liquid is passed through a sterile filter, which is divided into two chambers by a membrane that holds back microorganisms. A dialysis device with a sterile filter for recovering substituate is known from U.S. Pat. No. 6,187,207 B1, for example. 
         [0006]    Various methods are known for cleaning and disinfecting blood treatment devices. Before it is put into operation, the blood treatment device is flushed with a liquid that contains a cleaning agent and/or disinfectant. In this way, it is also possible for stubborn contaminants, for example biofilm, algae, protein deposits and blood residues, to be removed safely and quickly. 
         [0007]    An exception is when a blood treatment device is kept in storage over quite a long period, particularly before being put into operation for the first time. During this period, there is not only the problem of eliminating the possibility of contamination, but also that of protecting the blood treatment device against freezing. Therefore, for conservation, the liquid systems of the known blood treatment devices are generally filled with an antifreeze agent. 
         [0008]    An object of the present invention is to make available a method permitting conservation of an extracorporeal blood treatment device without the danger of formation of contaminants that could not be removed safely and quickly using the known cleaning and disinfecting agents. 
         [0009]    It is also an object of the present invention to make available a device with which the method for conserving the blood treatment device can be carried out easily and safely. 
         [0010]    A further object of the present invention is to create a blood treatment device with a device for carrying out the conservation method. 
         [0011]    Various investigations by the inventor into the causes of bacterial contamination in dialysis liquid systems have shown that the danger of contamination may increase if the dialysis liquid system were to be filled with an antifreeze agent for conserving the blood treatment device. 
         [0012]    A method according to the present invention for conserving a blood treatment device reduces the danger of contamination if the dialysis liquid system of the extracorporeal blood treatment device were to be filled with an antifreeze agent. It is based on introducing an antifreeze agent only into that part of the dialysis liquid system that includes the volume lying upstream of the sterile filter with which sterile substituate is recovered from the dialysis liquid. Accordingly, that part of the dialysis liquid system that included the volume lying downstream of the sterile filter is not filled with an antifreeze agent. This part of the dialysis liquid system is referred to hereinbelow as the substituate segment. The two volumes, which are filled with liquid or not filled with liquid, are separated by the membrane which divides the sterile filter into two chambers. 
         [0013]    Generally, a liquid that contains a cleaning and disinfecting agent is located in the substituate segment. The dialysis liquid system of the blood treatment devices is filled with such a liquid after being brought into operation for the first time. This liquid is drained off in the method according to the present invention. Thus, only the rest of the dialysis liquid system remains filled. 
         [0014]    A device according to the present invention for carrying out the method according to the present invention makes it possible, after removal of the sterile filter, to easily and safely separate the substituate segment from the rest of the dialysis liquid system and drain off liquid located in the substituate segment. The liquid in the substituate segment can be pumped off, for example. The dialysis liquid pump present in the dialysis liquid system of the known blood treatment device can be started up for this purpose. 
         [0015]    The sterile filters used in practice generally have an inlet and an outlet for the first chamber and an inlet and an outlet for the second chamber, so as to be able to operate both chambers in through-flow. If the known sterile filters are used to recover a sterile substituate, dialysis liquid is passed through the first chamber, while the substituate is drawn off from the second chamber. In sterile filters in which the first chamber and second chamber each have an inlet and an outlet, the inlet and outlet of both chambers must be attached to the blood treatment device. Consequently, the blood treatment device has four appliance-side attachment pieces, and the sterile filter has four filter-side attachment pieces. However, it is also possible that the second chamber of the sterile filter used to recover substituate has only an outlet. Then, the blood treatment device only needs to have three appliance-side attachment pieces, and the sterile filter only needs to have three filter-side attachment pieces. The present invention thus provides two alternative embodiments. 
         [0016]    In one alternative embodiment, the device according to the present invention has four attachment pieces, wherein the first and second attachment pieces are connected to each other by a first connection line and the third and fourth attachment pieces are connected to each other by a second connection line. With the device according to the present invention, a first flow connection can be established with the two attachment pieces to which the inlet and outlet of one chamber of the sterile filter are attached, and a flow connection can be established with the two attachment pieces to which the inlet and outlet of the second chamber of the sterile filter are attached. In this way, that part of the dialysis liquid system that includes the substituate segment is separated from the rest of the dialysis liquid system. Attachment pieces are understood as all means for establishing a connection or flow connection, and several attachment pieces can also form one unit. 
         [0017]    In the other alternative embodiment, the first and second attachment pieces are connected to each other by a first connection line, while the third and fourth attachment pieces are closed in a sterile manner, such that that part of the dialysis liquid system that includes the substituate segment can be separated from the rest of the dialysis liquid system. The third attachment piece can be designed in the manner of a closure cap, which closes the appliance-side attachment piece in a sterile manner when the device according to the present invention is attached to the blood treatment device. 
         [0018]    In order to be able to drain off liquid located in the substituate segment, the device according to the present invention has a venting means. The venting means is preferably once again a sterile filter through which air can flow into the volume included by the substituate segment while the liquid is being drained off. 
         [0019]    The device according to the present invention can be designed in different ways. The only crucial point is that said flow connections can be established between the appliance-side attachment pieces of the blood treatment device. It is advantageous if the device according to the present invention is designed in the manner of an adapter, which can be connected easily and safely to the appliance-side attachments when the sterile filter is detached from the blood treatment device. The connection lines between the attachment pieces can be fixed or flexible lines. They can be designed as channels in solid bodies or can be hose lines. 
         [0020]    The known blood treatment devices have holders for securing the sterile filters. Preferably, the device according to the present invention is designed in such a way that it can be inserted, in place of the sterile filters, with an exact fit into the holders of the blood treatment devices. 
         [0021]    The appliance-side attachment pieces and the attachment pieces of the device according to the present invention can be designed as plugs or sockets. Preferably, in each case two attachment pieces of the device according to the present invention form a common plug, which can be inserted with an exact fit into an appliance-side socket of the blood treatment device, to which otherwise the respective attachment pieces of the sterile filter are attached. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    An illustrative embodiment of the present invention is explained in more detail below with reference to the drawings, in which: 
           [0023]      FIG. 1  shows the main components of an extracorporeal blood treatment device, wherein a sterile filter is attached to the blood treatment device for the purpose of recovering a sterile substituate from the dialysis liquid, 
           [0024]      FIG. 2  shows the extracorporeal blood treatment device from  FIG. 1 , wherein the device according to the present invention is attached to the blood treatment device for the purpose of carrying out a method for conserving the blood treatment device, 
           [0025]      FIG. 3  shows a partial view of an alternative embodiment of the blood treatment device from  FIG. 1 , wherein an alternative embodiment of the sterile filter is attached to the blood treatment device for the purpose of recovering a sterile substituate from the dialysis liquid, and 
           [0026]      FIG. 4  shows the blood treatment device from  FIG. 3 , wherein an alternative embodiment of the device according to the present invention is attached to the blood treatment device for the purpose of recovering a sterile substituate from the dialysis liquid. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    The blood treatment device, in particular a hemo(dia)filtration device, has a dialyser  1 , which is separated by a membrane  2  into a dialysis liquid chamber  3 , through which dialysis liquid flows, and a blood chamber  4 , through which blood flows. 
         [0028]    A blood delivery line  5 , into which a blood pump  6  is coupled, leads to the blood chamber  4 , while a blood return line  7  issues from the blood chamber  4 . The blood delivery line  5  and blood discharge line  7  form, together with the blood chamber  4 , the extracorporeal blood circuit I of the blood treatment device. 
         [0029]    The dialysis liquid system II of the blood treatment device is described below. The dialysis liquid system II has a dialysis liquid delivery line  8 , which leads from a dialysis liquid source  9  to the dialysis liquid chamber  3 , and a dialysis liquid return line  10 , which issues from the dialysis liquid chamber  3  and leads to an outflow  11 . The dialysis liquid delivery line  8  has a first section  8 A, which leads from the dialysis liquid source  9  to the first chamber  12 A of a first sterile filter  12 . One chamber  13 A of a balance device  13  is coupled into the first section  8 A of the dialysis liquid delivery line  8 . The second section  8 B of the dialysis liquid delivery line  8  issues from the second chamber  12 B of the first sterile filter  12  and leads to the dialysis liquid chamber  3 . 
         [0030]    The dialysis liquid return line  10  divides into two sections  10 A and  10 B, which leads to the outlet  11 . A dialysis liquid pump  14  is coupled into the first section  10 A, while an ultrafiltrate pump  26  is coupled into the second section  10 B. The other chamber  13 B of the balance device  13  is also coupled into the first section  10 A. 
         [0031]    In order to recover a substituate from the dialysis liquid, the hemo(dia)filtration device has a second sterile filter  15 , which is divided by a semipermeable membrane  15 C into a first chamber  15 A and a second chamber  15 B. The second sterile filter  15  forms an exchangeable unit, which can be attached to the blood treatment device or removed from the treatment device. 
         [0032]    To attach and secure the second sterile filter  15 , the blood treatment device has a holder  16 , which has a first attachment piece  16 A, a second attachment piece  16 B, a third attachment piece  16 C and a fourth attachment piece  16 D. The appliance-side attachment pieces  16 A to  16 D can be designed as sockets. 
         [0033]    The second filter  15  has a first attachment piece  15 D, a second attachment piece  15 E, a third attachment piece  15 F and a fourth attachment piece  15 G. The filter-side attachment pieces  15 D to  15 G can be connected with an exact fit to the appliance-side attachment pieces  16 A to  16 D. The filter-side attachment pieces can be corresponding plugs. 
         [0034]    The third and fourth appliance-side attachment pieces  16 C,  16 D are connected to each other by a connection line  17 A, to which a bypass line  17 B is attached. Two shut-off elements  18 A and  18 B are located on the bypass line  17 B. Between the two shut-off elements  18 A and  18 B, a substituate line  17 D, into which a substituate pump  19  is coupled, branches off from a substituate port  17 C. The substituate line  17 D leads to the extracorporeal blood circuit I upstream or downstream of the blood chamber  4 , in order to be able to deliver substituate to the extracorporeal blood circuit I. While the substituate is being delivered, the shut-off element  18 A is opened and the shut-off element  18 B closed. 
         [0035]    The blood treatment device also has further shut-off elements and bypass lines, and other components too, but these are not shown for sake of clarity. 
         [0036]    The line sections of the dialysis liquid system II, through which sterile substituate is delivered from the second chamber  15 B of the second sterile filter  15  to the extracorporeal blood circuit I, represent the substituate segment  17  that has to be kept free of contaminants, in particular from the formation of a biofilm. The substituate segment therefore comprises all the lines or line sections that include the volume lying downstream of the sterile filter, for example the connection line  17 A and the line section of the bypass line  17 B upstream of the substituate port  17 C. 
         [0037]    The blood treatment devices are tested after assembly. The dialysis liquid system II is then filled completely with a liquid that contains a cleaning and disinfecting agent. All the line sections of the dialysis liquid system are thus filled. At this time, the substituate line  17 D is not generally attached to the substituate port  17 C. 
         [0038]    For the subsequent transport and storage of the blood treatment device, the method according to the present invention is carried out using the device according to the present invention. 
         [0039]    The first and second sterile filters  12 ,  15  are removed. The first sterile filter  12  is replaced in a known manner by a known bypass piece. The second sterile filter  15  is replaced by the device according to the present invention, which device is described below with reference to  FIG. 2 . 
         [0040]    The device  20  according to the present invention for carrying out the conservation method has, like the sterile filter  15 , a first attachment piece  20 A, a second attachment piece  20 B, a third attachment piece  20 C and a fourth attachment piece  20 D, which can be connected to the appliance-side attachment pieces  16 A to  16 D. The attachment pieces can once again be designed as plugs that can be inserted with an exact fit into sockets. 
         [0041]    In a preferred embodiment, the first and third attachment pieces  20 A,  20 C are designed as a common plug, while the second and fourth attachment pieces  20 B,  20 D are designed as a second plug. However, all of the attachment pieces can also be separate from one another. 
         [0042]    The first and second attachment pieces  20 A,  20 B are connected to each other by a first connection line  21 , and the third and fourth attachment pieces  20 C,  20 D are connected to each other by a second connection line  22 . The first and second connection lines  21 ,  22  can be hose lines. A third line  23 , which is closed by a sterile filter  24 , branches off from the second connection line  22 . The sterile filter  24  has a first chamber  24 A and a second chamber  24 B, which are separated by a semipermeable membrane  24 C. The first chamber  24 A of the sterile filter  24  is connected to the third line  22 , in particular a hose line. A hose clamp  25  is provided for clamping off the hose line  23 . 
         [0043]    The device according to the present invention preferably forms a unit that can be easily and safely secured to the holder  16  in place of the sterile filter  15 . 
         [0044]    When the device  20  according to the present invention is attached to the blood treatment device, a flow connection is established between the dialysis liquid source  9  and the dialysis liquid chamber  3 , while the substituate segment  17  is separated from the rest of the dialysis liquid system. The liquid located in the substituate segment  17  decoupled from the rest of the dialysis liquid system is now drawn off, such that the substituate segment is free of liquid. For this purpose, the shut-off element  25  on the device according to the present invention is opened, such that air can pass into the substituate segment in order to vent the volume enclosed by the substituate segment  17 . The liquid can be conveyed, for example, to the outflow  11 , for which purpose the pumps  14  and  26  can be operated. The shut-off element  25  is then closed again, and the rest of the dialysis liquid system is filled completely with a liquid that contains an antifreeze agent. The blood treatment device remains in this state until installation at the dialysis centre. 
         [0045]    When the dialysis device is started up, new sterile filters  12  and  15  are used. The compulsory cleaning and disinfecting cycle then follows. Any bacteria are either killed off or flushed out by the direct cleaning and disinfecting. Thus, the first use of a filter and all subsequent exchanges can be classed as aseptic procedures, which guarantee that the substituate segment is permanently sterile. 
         [0046]    It has been found in tests that, in the substituate segment not filled with antifreeze agent, and even after quite a long storage period, a biofilm cannot form that cannot be safely and quickly removed using conventional cleaning and disinfecting measures. 
         [0047]    An alternative embodiment of the blood treatment device, and of the device according to the present invention for attachment to the blood treatment device, is described below with reference to  FIGS. 3 and 4 , which embodiment differs from the embodiment described with reference to  FIGS. 1 and 2  only in that the blood treatment device and the device according to the present invention have only three attachment pieces. The corresponding parts are provided in  FIGS. 3 and 4  with the same reference signs as in  FIGS. 1 and 2 . Instead of the two filter-side attachment pieces  15 F and  15 G ( FIG. 1 ), the second chamber  15 B of the second sterile filter  15  has only one attachment piece  15 F′ ( FIG. 3 ), and, instead of the two appliance-side attachment pieces  16 C and  16 D ( FIG. 1 ), the blood treatment device has only one attachment piece  16 C′ ( FIG. 3 ), wherein the third filter-side attachment piece  15 F′ is attached to the third appliance-side attachment piece  16 C′ ( FIG. 3 ). A connection line for the connection of two appliance-side attachment pieces is not required here. The bypass line  17 B of the substituate segment  17  is therefore connected directly to the third appliance-side attachment piece  16 C′. The first chamber  24 A of the sterile filter  24  is connected directly to the third attachment piece  20 C′ of the device  20  according to the present invention via the connection line  23  ( FIG. 4 ), such that the substituate segment  17  is closed in a sterile manner ( FIG. 4 ) when the device according to the present invention is attached to the blood treatment device.