Abstract:
The present application discloses novel systems for conducting the filtration of blood using manifolds. The manifolds integrate various sensors and have fluid pathways formed therein to direct fluids from various sources through the requisite blood filtration or ultrafiltration system steps.

Description:
CROSS-REFERENCE 
       [0001]    The present application is a continuation of U.S. patent application Ser. No. 12/237,914, filed on Sep. 25, 2008, which calls priority to U.S. Patent Provisional Application No. 60/975,157 filed on Sep. 25, 2007. 
     
    
     FIELD 
       [0002]    The present application relates generally to the field of blood purification systems and methods. More specifically, the present invention relates to novel methods and systems for conducting hemofiltration and hemodialysis. 
       BACKGROUND 
       [0003]    Blood purification systems, which are used for conducting hemodialysis, hemodiafiltration or hemofiltration, involve the extracorporeal circulation of blood through an exchanger having a semi permeable membrane. Such systems further include a hydraulic system for circulating blood and a hydraulic system for circulating replacement fluid or dialysate comprising the main electrolytes of the blood in concentrations close to those in the blood of a healthy subject. Most of the conventionally available blood purification systems are, however, quite bulky in size and difficult to operate. Further, the design of these systems makes them unwieldy and not conducive to the use and installation of disposable components. 
         [0004]    The conventional design of prior art hemodiafiltration systems employs single pass systems. In single pass systems, the dialysate passes by the blood in the dialyzer one time and then is disposed. Single pass systems are fraught with a plurality of disadvantages, arising from the use of large amounts of water:
       Assuming a 50% rejection rate by the R.O. (Reverse Osmosis) system, at least 1000 to 1500 ml/min of water is required.   A water purification system for providing a continuous flow of 100 to 800 ml/minute of purified water is required.   An electrical circuit of at least 15 amps is required, in order to pump 100 to 800 ml of water/minute, and   A floor drain or any other reservoir capable of accommodating at least 1500 ml/min of used dialysate and RO rejection water.       
 
         [0009]    U.S. Pat. No. 4,469,593 to Ishihara, et al discloses “a blood purification apparatus [that] includes an extracorporeal circulation system, a blood purifier provided in the system for purifying blood by dialysis or filtration through a semi permeable membrane, a circulation blood volume measuring instrument for measuring changes in a circulating blood volume within a patient&#39;s body, a control section comprising a memory for storing a program for a pattern of changes in the circulating blood volume during blood purification, the program being matched to the condition of a patient, and a regulator connected to the extracorporeal circulation system and the control section, for controlling the circulating blood volume, the regulator being controlled by the control section on the basis of the circulating blood volume measured during blood purification and the programmed amount. In this apparatus, optimum blood purification is carried out while maintaining the circulating blood volume at a prescribed level.” 
         [0010]    U.S. Pat. No. 5,114,580 to Ahmad, et al discloses “[a] hemodialysis system that has a blood circuit and a hemofiltrate circuit interconnected at a hemofilter and an air collection chamber. If an infusion of sterile fluid to the returning blood is needed during the dialysis treatment, filtrate in the filtrate circuit is pumped back into the blood circuit. This is also done to purge the blood circuit of blood and return it to the patient at the conclusion of a dialysis treatment. A blood pump in the blood circuit incorporates a flexible vessel in conjunction with pinch valves which self expand in a controlled manner from a compressed condition to fill with blood from the patient in a suction stroke controlled by the patient&#39;s blood delivery rate. Compression of the vessel by an external member then forces the blood through the rest of the blood circuit.” 
         [0011]    U.S. Pat. No. 6,303,036 to Collins, et al discloses “[a]n apparatus and method for hemodiafiltration . . . [that] includes a first dialyzer cartridge containing a semi-permeable membrane that divides the dialyzer into a blood compartment and a dialysate compartment. Fluid discharged from the blood compartment of the first dialyzer cartridge is mixed with sterile substitution fluid to form a fluid mixture and the mixture enters a second dialyzer cartridge. The second dialyzer cartridge contains a second semi-permeable membrane which divides the second dialyzer cartridge into a blood compartment and a dialysate compartment. Hemodiafiltration occurs in both cartridges.” 
         [0012]    None of these systems, however, address the aforementioned disadvantages of prior art blood purification systems. Conventional systems are also less reliable because of the necessity of using a myriad of tubes comprising the fluid circuits of the purification systems, thus increasing the risks of leakage and breakage. 
         [0013]    Further, conventional blood purification systems do not have built-in functionality to check the integrity and authenticity of the disposables employed in the system. Still further, conventional systems lack the capability to allow the user of the system to interact with a remote patient care facility. 
         [0014]    Accordingly, there is a need for a multiple-pass sorbent-based hemodiafiltration system that lowers the overall water requirements relative to conventional systems. There is also a need for a novel manifold that can be used in a single pass sorbent-based hemodiafiltration system as well as in the multiple-pass system of the present invention, which offers a lightweight structure with molded blood and dialysate flow paths to avoid a complicated mesh of tubing. It is also desirable that the novel manifold has integrated blood purification system components, such as sensors, pumps and disposables, thus enhancing fail-safe functioning of a patient&#39;s blood treatment. 
       SUMMARY 
       [0015]    The present application discloses novel systems for conducting the filtration of blood using manifolds. In one embodiment, the manifold comprises a first flow path formed in a plastic substrate comprising a plurality of sensors integrated therein and tubing that receives blood from a first inlet port and passes blood to a dialyzer; a component space formed in the plastic substrate for receiving a dialyzer; a second flow path formed in the plastic substrate comprising at least one blood leak sensor integrated therein and tubing that receives a first fluid from a dialyzer and passes the first fluid to a first outlet port and a second outlet port, wherein the first outlet port is in fluid communication with a collection reservoir and the second outlet port is in fluid communication with a dialysate regeneration system; a third flow path formed in the plastic substrate comprising tubing that receives a second fluid from a second inlet port and passes the second fluid to the dialyzer; and a fourth flow path formed in the plastic substrate comprising at least one sensor and tubing that receives purified blood from the dialyzer and passes the purified blood to a third outlet port. 
         [0016]    Optionally, a pump, such as a peristaltic pump, is in fluid communication with the first flow path. The sensors integrated into the first flow path are at least one of a pressure transducer and a flow meter. The transducers are directly molded into the manifold and are made of synthetic rubber. A flow meter is integrated into the second flow path. At least two pumps are in fluid communication with the second flow path. The fourth flow path further comprises tubing for receiving fluid from a third inlet port. The third inlet port is connected to a substitution fluid container. 
         [0017]    In another embodiment, the present application discloses a manifold for conducting filtration of blood comprising a first inlet port, a first flow path formed in a plastic substrate comprising a plurality of sensors integrated therein wherein the first flow path forms a pathway for transporting blood from the first inlet port and to a component space formed in the plastic substrate, a second flow path formed in the plastic substrate comprising at least one blood leak sensor integrated therein wherein the second flow path forms a pathway for transporting a first fluid from the component space to a first outlet port and a second outlet port, a third flow path formed in the plastic substrate comprising tubing wherein the third flow path forms a pathway for transporting a second fluid from a second inlet port to the component space, and a fourth flow path formed in the plastic substrate comprising at least one sensor, wherein the fourth flow path forms a pathway for transporting purified blood from the component space to a third outlet port. 
         [0018]    In another embodiment, the present application discloses a system for conducting ultrafiltration having a manifold comprising a first flow path formed in a plastic substrate comprising a plurality of sensors integrated therein and tubing that passes blood to a first outlet port, wherein the first outlet port is in fluid communication with a first pump external to the manifold, receives blood from a first inlet port, wherein the first inlet port is in fluid communication with the first pump, and passes the blood to a dialyzer; a component space formed in the plastic substrate for receiving a dialyzer; a second flow path formed in the plastic substrate comprising at least one sensor integrated therein and tubing that receives a first fluid from the dialyzer and passes the first fluid to a second outlet port, wherein second outlet port is in fluid communication with a second pump; and a third flow path formed in the plastic substrate comprising at least one sensor and tubing that receives the first fluid from a second inlet port, wherein the second inlet port is in fluid communication with the second pump, and passes said first fluid to a third outlet port. 
         [0019]    Optionally, the first flow path comprises at least two pressure sensors. The at least one sensor of the third flow path is a blood leak sensor. The system further comprises a fourth flow path formed in the substrate comprising at least one sensor and tubing that receives a second fluid from said dialyzer and passes said second fluid to a fourth outlet port. The at least one sensor in the fourth flow path is an air detector. The third flow path further comprises a flow meter. The at least one sensor in the second flow path is a pressure sensor. The system further comprises a housing for containing the first pump, said second pump, and the manifold. 
         [0020]    In another embodiment, the present application discloses a manifold for conducting ultrafiltration comprising a first flow path formed in a plastic substrate comprising at least one sensor integrated therein wherein the first flow path forms a pathway for passing blood from a first inlet port to a component space, a component space formed in the plastic substrate, a second flow path formed in the plastic substrate comprising at least one sensor integrated therein wherein the second flow path forms a pathway for passing a first fluid from the component space to a second outlet port; and a third flow path formed in the plastic substrate comprising at least one blood leak sensor and flow meter, wherein the third flow path forms a pathway for passing said first fluid from a second inlet port to a third outlet port. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    These and other features and advantages of the present invention will be appreciated, as they become better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
           [0022]      FIG. 1 a    is a functional block diagram of one embodiment of a multiple-pass sorbent-based hemodiafiltration system of the present invention; 
           [0023]      FIG. 1 b    is an illustration of one embodiment of a hemodiafiltration manifold of the present invention; 
           [0024]      FIGS. 2 a  and 2 b    are a functional diagram and an illustration, respectively, of one embodiment of an ultrafiltration manifold used to support an ultrafiltration treatment system; 
           [0025]      FIG. 2 c    shows a modular assembly of an ultrafiltration manifold in one embodiment of the present invention; 
           [0026]      FIG. 2 d    shows a larger view of a mid-body module in one embodiment of the ultrafiltration manifold of the present invention; 
           [0027]      FIG. 3  is a functional block diagram showing one embodiment of an ultrafiltration treatment system of the present invention; and 
           [0028]      FIG. 4  is a functional block diagram showing one embodiment of an electronic-based lockout system of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0029]    The present application discloses a plurality of novel embodiments which can be practiced independently or in novel combination with each other. 
         [0030]    In one embodiment, the present application discloses a multiple-pass, sorbent-based hemodiafiltration system, advantageously combining hemofiltration and hemodialysis in a multiple pass configuration. 
         [0031]    In another embodiment, the present application discloses novel manifold supports for blood purification systems, such as, but not limited to hemodiafiltration and ultrafiltration. In one embodiment, the novel manifold of the present invention comprises a composite plastic manifold, into which the blood and dialysate flow paths are molded. This plastic based manifold can be used with the multiple-pass sorbent-based hemodiafiltration system of the present invention. 
         [0032]    In another embodiment, blood purification system components, such as sensors, pumps, and disposables are integrated into the molded novel manifold. Preferably, disposable items such as but not limited to dialyzer and sorbent cartridges, are detachably loadable on to the manifold. In one embodiment, sensors, such as but not limited to those for pressure and air monitoring and blood leak detection are also integrated with the manifold. In another embodiment, blood circuit pumps are integrated with the manifold. In another embodiment, the valve membranes are integrated with the manifold. 
         [0033]    In yet another embodiment, an ultrafiltration system is integrated into a novel manifold by molding both blood and ultrafiltrate flow paths in the manifold. In one embodiment, a hemofilter cartridge is placed into the manifold so that it can be removed and replaced. 
         [0034]    In one embodiment, the manifolds disclosed herein comprise single, composite plastic structures, also referred to as substrates or housings, that can be made by combining two plastic substrate halves. 
         [0035]    In another embodiment, the present application discloses a dialysis system that supports an electronic-based lockout system. Accordingly, in one embodiment, a reader is mounted on the system housing(s) and/or manifold(s), such as but not limited to the hemodiafiltration and ultrafiltration manifolds, and reads identification indicia on disposable items that are loaded onto the dialysis housing(s) and/or manifolds. The reader communicates with a database over a network, such as a public network or private network, to check if the disposable items are valid, accurate, or of sufficient integrity to be safe and ready for use. This is done by querying information on the disposable items from the remote database, based on the identification indicia of the items. If the disposable item has an “invalid” or “compromised” status, (based on the information received from the database) the system “locks out” the use of the loaded disposable, and thus does not allow the user to proceed with using the system for treatment. 
         [0036]    Reference will now be made to specific embodiments of the present invention. The present invention is directed toward multiple embodiments. Language used in this specification should not be interpreted as a general disavowal of any one specific embodiment or used to limit the claims beyond the meaning of the terms used therein. 
         [0037]      FIG. 1 a    is a functional block diagram of one embodiment of a multiple-pass sorbent-based hemodiafiltration system of the present invention. In one embodiment, hemodiafiltration system  100  employs a dialyzer cartridge comprising a high flux membrane to remove toxins from the blood both by diffusion and by convection. The removal of toxins by diffusion is accomplished by establishing a concentration gradient across the semi-permeable membrane by allowing a dialysate solution to flow on one side of the membrane in one direction while simultaneously allowing blood to flow on the other side of the membrane in opposite direction. To enhance removal of toxins using hemodiafiltration, a substitution fluid is continuously added to the blood either prior to the dialyzer cartridge (pre-dilution) or after the dialyzer cartridge (post-dilution). An amount of fluid equal to that of the added substitution fluid is “ultra-filtered” across the dialyzer cartridge membrane, carrying the added solutes with it. 
         [0038]    Now referring to  FIG. 1 a   , in one embodiment, the blood containing toxins is pumped from a blood vessel of a patient by a blood pump  101  and is transferred to flow through dialyzer cartridge  102 . Optionally, inlet and outlet pressure sensors  103 ,  104  in the blood circuit measure the pressure of blood both before it enters the dialyzer cartridge  102  at the blood inlet tube  105  and after leaving the dialyzer cartridge  102  at the blood outlet tube  106 . Pressure readings from sensors  103 ,  104 ,  128  are used as a monitoring and control parameter of the blood flow. An ultrasonic flow meter  121  may be interposed in the portion of blood inlet tube  105  that is located directly upstream from the blood pump  101 . The ultrasonic flow meter  121  is positioned to monitor and maintain a predetermined rate of flow of blood in the impure blood supply line. A substitution fluid  190  may be continuously added to the blood either prior to the dialyzer cartridge (pre-dilution) or after the dialyzer cartridge (post-dilution). 
         [0039]    In one embodiment, as shown in  FIGS. 1 a    and  1   b,  dialyzer cartridge  102  comprises a semi-permeable membrane  108  that divides the dialyzer  102  into a blood chamber  109  and a dialysate chamber  111 . As blood passes through the blood chamber  109 , uremic toxins are filtered across the semi-permeable membrane  108  on account of convection. Additional blood toxins are transferred across the semi-permeable membrane  108  by diffusion, primarily induced by a difference in concentration of the fluids flowing through the blood and dialysate chambers  109 ,  111  respectively. The dialyzer cartridge used may be of any type suitable for hemodialysis, hemodiafiltration, hemofiltration, or hemoconcentration, as are known in the art. In one embodiment, the dialyzer  102  contains a high flux membrane. Examples of suitable dialyzer cartridges include, but are not limited to, Fresenius® F60, F80 available from Fresenius Medical Care of Lexington, Mass., Baxter CT 110, CT 190, Syntra® 160 available from Baxter of Deerfield, Ill., or Minntech Hemocor HPH® 1000, Primus® 1350, 2000 available from Minntech of Minneapolis, Minn. 
         [0040]    In one embodiment of the present invention, dialysate pump  107  draws spent dialysate from the dialyzer cartridge  102  and forces the dialysate into a dialysate regeneration system  110  and back into the dialyzer cartridge  102  in a multiple pass loop, thus generating “re-generated” or fresh dialysate. Optionally, a flow meter  122  is interposed in the spent dialysate supply tube  112  upstream from dialysate pump  107 , which monitors and maintains a predetermined rate of flow of dialysate. A blood leak sensor  123  is also interposed in spent dialysate supply tube  112 . 
         [0041]    The multi-pass dialysate regeneration system  110  of the present invention comprises a plurality of cartridges and/or filters containing sorbents for regenerating the spent dialysate. By regenerating the dialysate with sorbent cartridges, the hemodiafiltration system  100  of the present invention requires only a small fraction of the amount of dialysate of a conventional single-pass hemodialysis device. In one embodiment, each sorbent cartridge in the dialysate regeneration system  110  is a miniaturized cartridge containing a distinct sorbent. For example, the dialysate regeneration system may employ five sorbent cartridges, wherein each cartridge separately contains activated charcoal, urease, zirconium phosphate, hydrous zirconium oxide and activated carbon. In another embodiment each cartridge may comprise a plurality of layers of sorbents described above and there may be a plurality of such separate layered cartridges connected to each other in series or parallel in the dialysate regeneration system. Persons of ordinary skill in the art would appreciate that activated charcoal, urease, zirconium phosphate, hydrous zirconium oxide and activated carbon are not the only chemicals that could be used as sorbents in the present invention. In fact, any number of additional or alternative sorbents, including polymer-based sorbents, could be employed without departing from the scope of the present invention. 
         [0042]    The sorbent-based multiple-pass hemodiafiltration system of the present invention provides a plurality of advantages over conventional single-pass systems. These include:
       No requirement of a continuous water source, a separate water purification machine or a floor drain as the system of present invention continuously regenerates a certain volume of dialysate. This allows for enhanced portability.   The present system requires low amperage electrical source, such as 15 amps, because the system recycles the same small volume of dialysate throughout the diafiltration procedure. Therefore, extra dialysate pumps, concentrate pumps and large heaters used for large volumes of dialysate in single pass dialysis systems are not required.   The present system can use low volumes of tap water, in the range of 6 liters, from which dialysate can be prepared for an entire treatment.   The sorbent system uses sorbent cartridges that act both as a water purifier and as a means to regenerate used dialysate into fresh dialysate.       
 
         [0047]    While the current embodiment has separate pumps  101 ,  107  for pumping blood and dialysate through the dialyzer, in an alternate embodiment, a single dual-channel pulsatile pump that propels both blood and dialysate through the hemodiafiltration system  100  may be employed. Additionally, centrifugal, gear, or bladder pumps may be used. 
         [0048]    In one embodiment, excess fluid waste is removed from the spent dialysate in the spent dialysate tube  112  using a volumetric waste micro-pump  114  and is deposited into a waste collection reservoir  115 , which can be periodically emptied via an outlet such as a tap. An electronic control unit  116  comprising a microprocessor monitors and controls the functionality of all components of the system  100 . 
         [0049]    In one embodiment, dia-filtered blood exiting dialyzer cartridge  102  is mixed with regulated volumes of sterile substitution fluid that is pumped into the blood outlet tube  106  from a substitution fluid container  117  via a volumetric micro-pump  118 . Substitution fluid is typically available as a sterile/non-pyrogenic fluid contained in flexible bags. This fluid may also be produced on-line by filtration of a non-sterile dialysate through a suitable filter cartridge rendering it sterile and non-pyrogenic. 
         [0050]      FIG. 1 b    is an illustration of one embodiment of a hemodiafiltration manifold of the present invention. In one embodiment, hemodiafiltration manifold  120  comprises the blood and dialysate flow paths shown in the hemodialfiltration system  100  shown in  FIG. 1   a.  As shown in  FIG. 1   b,  the blood and dialysate flow paths are molded in a single compact plastic unit. Fluid flows in and out of the manifold at defined inlet and outlet ports, such as to and from a patient, to a waste reservoir, to a dialysate regeneration system, or from a substitution fluid reservoir. The sensors, such as dialyzer blood inlet pressure transducers  103 ,  128  and blood outlet pressure transducer  104 ; flow meters  121 ,  122 ; blood leak sensor  123 ; disposable sorbent cartridges of the dialysate regeneration system  110 , which is external to the manifold; and volumetric pumps  101 ,  107 ,  114  and  118  are all integrated into the molding of the manifold  120 . The disposable dialyzer  102  is directly integrated with the corresponding space in the manifold  120  to complete the blood and dialysate circuits, as shown in  FIG. 1   b.  Preferably, pressure transducers  103 ,  104  are directly molded into the manifold with a multi-shot plastic injection molding process which reduces the need for manual assembly of these components. In one embodiment, the diaphragm of the transducers are made of synthetic rubber, such as polyisoprene, and co-molded into the ABS plastic substrate. Collection reservoir  115  and substitution fluid container  117  are also external to the manifold  120 . 
         [0051]      FIG. 3  is a functional block diagram showing one embodiment of an ultrafiltration treatment system  300  of the present invention. As shown in  FIG. 3 , blood from a patient is drawn into blood inlet tubing  301  by a pump, such as a peristaltic blood pump,  302  that forces the blood into a hemofilter cartridge  304  via blood inlet port  303 . Inlet and outlet pressure transducers  305 ,  306  are connected in-line just before and after the blood pump  302 . The hemofilter  304  comprises a semi-permeable membrane that allows excess fluid to be ultrafiltrated from the blood passing therethrough, by convection. Ultrafiltered blood is further pumped out of the hemofilter  304  through blood outlet port  307  into blood outlet tubing  308  for infusion back to into the patient. Regulators, such as clamps,  309 ,  310  are used in tubing  301  and  308  to regulate fluid flow therethrough. 
         [0052]    A pressure transducer  311  is connected near the blood outlet port  307  followed by an air bubble detector  312  downstream from the pressure transducer  311 . An ultrafiltrate pump, such as a peristaltic pump,  313  draws the ultrafiltrate waste from the hemofilter  304  via UF (ultrafiltrate) outlet port  314  and into the UF outlet tubing  315 . A pressure transducer  316  and a blood leak detector  317  are transposed into the UF outlet tubing  315 . Ultrafiltrate waste is finally pumped into a waste collection reservoir  318  such as a flask or soft bag, attached to the leg of an ambulatory patient and equipped with a drain port to allow intermittent emptying. The amount of ultrafiltrate waste generated can be monitored using any measurement technique, including a scale or flow meter. The microcontroller monitors and manages the functioning of the blood and UF pumps, pressure sensors as well as air and blood leak detectors. Standard luer connections such as luer slips and luer locks are used for connecting tubing to the pumps, the hemofilter and to the patient. 
         [0053]      FIGS. 2 a  and 2 b    are a functional diagrams and an illustration, respectively, of one embodiment of an ultrafiltration manifold  200  used to support an ultrafiltration treatment system. In one embodiment, the ultrafiltration manifold  200  is an easy to assemble compact plastic unit that has built-in molded blood and waste flow paths. Optionally, the sensors, pumps and hemofilter cartridges can also be integrated with the compact plastic unit by insertion into concave moldings in the unit. In one embodiment, the ultrafiltration system of the present invention is capable of operating more than 8 hours per treatment and for up to 72 hours continuously. It should be appreciated that fluid flows in and out of the manifold through defined inlet and outlet ports, such as to and from external pumps, to a waste UF reservoir, or to a patient return line. 
         [0054]      FIG. 2 c    shows a modular assembly of an ultrafiltration manifold in one embodiment of the present invention. As shown in  FIG. 2   c,  the housing  290  comprises blood and waste pumps  203 ,  213  respectively in a pumping section  230 ; a module  240  comprises molded flow paths for blood and ultrafiltrate wastes and a hemofilter module  250  comprising a hemofilter cartridge  208 . This modular design allows quick and easy assembly of various modules into a single compact structure  290 . 
         [0055]      FIG. 2 d    shows an enlarged view of a mid-body module  240  in one embodiment of the ultrafiltration manifold of the present invention. In one embodiment, mid-body module  240  comprises built-in molded flow paths  241  for carrying blood and waste. Connection ports  242  are also molded into the mid-body module for connecting (via luer connectors and tubing) to pumps at one end of mid-body module  240  and to a hemofilter cartridge at the other end of mid-body module  240 . 
         [0056]    Referring back to  FIGS. 2 a  and 2 b    simultaneously, blood is drawn into the manifold  200  via blood inlet port  201  and molded flow path  202  using a blood volumetric pump  203 . Blood volumetric pump  203  pumps blood into hemofilter cartridge  208  via the molded flow path  204 . Inlet pressure sensors  206 ,  207  are also integrated into manifold  200  in molded flow paths  202 ,  204 . 
         [0057]    In one embodiment the hemofilter cartridge  208  comprises a hollow tube further comprising a plurality of hollow fiber tubes whose walls act as a semi-permeable membrane. The plurality of semi-permeable, hollow fiber tubes divide the hemofilter cartridge  208  into blood flow regions  205  within the hollow fiber tubes and a filtrate or permeate region  209  outside the hollow fiber tubes. As blood passes through blood regions  205 , plasma water passes across the semi-permeable membranes of the hollow fiber tubes. The hemofilter cartridge  208  is a small hemofilter. More concentrated blood flows out from the cartridge  208  through molded flow path  210  and out of the manifold  200  through a blood outlet port  211 . An air detector  212  is also integrated into blood return flow path  210 . 
         [0058]    The following are exemplary physical specifications of a hemofilter  208  in accordance with one embodiment of the present invention: 
         [0000]    
       
         
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 Membrane Surface Area (m 2 ) 
                 ≦0.1 
               
               
                   
                 Prime Volume (ml) 
                 ≦10 
               
               
                   
                 Molecular Weight cut-off (Daltons) 
                 65,000 
               
               
                   
                 Pressure Drop3 (mmHg) 
                 ≦50 (Qb = 50 ml/min 
               
               
                   
                 Maximum Transmembrane Pressure 
                 ≧500 
               
               
                   
                 (mmHg) 
                   
               
               
                   
                 Overall Unit Length (cm) 
                 12-15 
               
               
                   
                 Filtration rate 
                 8-10 ml/min 
               
               
                   
                   
                 @100 mmHg 
               
               
                   
                   
                 @ 50 ml/min Qb 
               
               
                   
                 Tubing Connections 
                   
               
               
                   
                 Blood 
                 Male Luer 
               
               
                   
                 Filtrate 
                 Slip fit (straight) 
               
               
                   
                 Sterilization: 
                 ETO or gamma 
               
               
                   
                 Membrane Material: 
                 Polysulfone 
               
               
                   
                   
                 (preferred) 
               
               
                   
                 Housing material 
                 Polycarbonate 
               
               
                   
                 Potting material 
                 Polyurethane 
               
               
                   
                 Sieving coefficients 
                   
               
               
                   
                 Urea 
                 1.00 
               
               
                   
                 Creatinine 
                 1.00 
               
               
                   
                 Vit B12 
                 0.98 
               
               
                   
                 Middle molecule/size 
                 ≧0.20 
               
               
                   
                   
                 17,000 
               
               
                   
                 Albumin 
                 ≦.03 
               
               
                   
                   
               
             
          
         
       
     
         [0059]    Referring back to  FIGS. 2 a    and  2   b,  ultrafiltrate waste from the permeate region  209  is drawn out by waste volumetric pump  213  through molded flow path  214 , which, in one embodiment, has an integrated pressure sensor  215  located in-line of flow path  214 . The ultrafiltrate waste is pumped through molded flow path  216 , which, in one embodiment, has an integrated blood leak detector  217  and waste ultrafiltrate flow meter  218 , in-line with flow path  216  leading out of the manifold  200  through a waste outlet port  219 . 
         [0060]    In one embodiment, the hemofilter cartridge  208  is disposable and can be removably integrated into the corresponding molded concavity in the manifold  200  to complete the ultrafiltration circuit. The manifold  200  also provides an interface to a redundant pinch valve to prevent air from entering the patient&#39;s vascular system. The pinch valve is designed such that it is in closed (occluded) position when no electrical power is applied. 
         [0061]    The molded flow paths  202 ,  204 ,  210 ,  214  and  216  define the blood and ultrafiltrate flow circuits of the manifold  200 . In one embodiment, these flow paths comprise disposable tubing and a plurality of interfacing components, such as joints, that are suitable for blood and ultrafiltrate contact for at least 3 days. The joints preferably are designed to have at least 51 lbs. strength and seal to 600 mmHg (that is, greater than hemofilter maximum trans-membrane pressure). In one embodiment, the blood set tubing corresponding to flow paths  202 ,  204  and  210  have suitable length and internal diameter for supplying a blood flow of 50 mL/minute. In one embodiment the prime volume of blood set tubing, including the hemofilter  205 , is less than 40 mL. The blood set tubing interfaces with the blood volumetric pump  203 . Blood pump  203  tubing, in one embodiment, is of Tygon brand, formulation S-50-HL, size ⅛″ ID× 3/16″ OD× 1/32″ Wall. 
         [0062]    Similarly, in one embodiment, the ultrafiltrate set tubing corresponding to flow paths  214  and  216  are capable of supplying an ultrafiltrate flow of 500 mL/Hr (8.33 mL/minute). The ultrafiltrate set tubing also interfaces with the waste volumetric pump  213 . Waste pump  213  tubing, in one embodiment, is of Tygon brand, formulation S-50-HL, size 3/32″ ID× 5/32″ OD× 1/32″ Wall. 
         [0063]    Since the ultrafiltration manifolds of the present invention comprise molded flow paths for blood, dialysate, waste fluids, and substitution fluids, the entire flow path can be easily manufactured as portable composite manifolds. The manifolds are also easy to handle since all flexible tubing outside the manifolds are attached on one side of the manifolds. Use of manifolds with built-in molded flow paths enhances fail-safe treatment as the chances of disconnection, misassembly and leakage are minimized in comparison to prior art systems that use a myriad of flexible tubing. Use of the novel manifolds also enhances ease of use leading to enhanced portability. 
         [0064]    In one embodiment the dialysis manifolds shown in  FIGS. 1 b  and 2 b    are standalone compact units such that they can be individually and separately used to process blood from a patient. In another embodiment the two manifolds are connectable to each other to function as a dual stage blood processing system. In one example, blood is drawn from an arterial site in a patient and passed through a dialyzer where a large amount of waste fluid is convected out. The manifold is used to return an equal amount of fluid back to the blood, before the blood is reinfused. The manifold measures and dumps the waste fluid into a waste bag. 
         [0065]    In another embodiment of the present invention, the novel manifolds described above also comprise an electronic-based lockout (“e-lockout”) system.  FIG. 4  is a functional block diagram showing one embodiment of the e-lockout system of the present invention. In one embodiment e-lockout system  400  comprises a reader  401  that detects and reads identification data  406  embedded in disposable items  402 , such as disposable manifolds, disposable sorbents used in dialysate regeneration and/or dialyzers. The identification data  406  may be stored on disposable items  402  via barcode, RFID tags, EEPROM, microchip or any other identification means that uniquely identifies the disposable items  402  to be used in the dialysis system  403 . The reader  401  is correspondingly a barcode reader, RFID reader, microchip reader, or any other reader that corresponds to the identification technology employed as is known to persons of ordinary skill in the art. In one embodiment, the reader  401  is connected with a transceiver for wirelessly connecting to a remote database  405  through a network  404  such as Internet or any other public or private network known to persons of ordinary skill in the art. In another embodiment, the reader  401  is directly aligned with the identification data  406  [not shown]. 
         [0066]    The database  405 , located remote from the dialysis system, stores a plurality of information about the disposable items  402  that can be used in the system  403 . The information comprises unique identification data  406  along with information for the corresponding disposable item such as authenticity, usability in terms of whether the item is likely to be in working condition, or not or if the item has been recalled by the manufacturer owing to a defect, its expiry date, if any, and/or any other such value-added information that would advantageously be evident to persons of ordinary skill in the art. 
         [0067]    In operation, when a disposable item  402 , such as a dialyzer, manifold, or a hemofilter cartridge, is loaded into the system  403  the reader  401  detects the disposable item  402  through identification data  406  embedded onto item  402 . This identification data  406  is read by reader  401 , which, in turn, communicates, either wired or wirelessly, with database  405  to request more information on the item  402  stored therein, based on identification data  406 , or confirm the validity or integrity of the item  402  based on identification data  406 . 
         [0068]    For example, in one embodiment, dialyzer cartridge  402  identified by the reader  401  may have been called back by the manufacturer on account of some defect. This call-back information is stored on the database  405  and is returned back to the reader  401  as a result of the request signal sent by the reader  401  to the database  405  trough the network  404 . As a result of the call-back information received from the database  405  the microprocessor controlling the blood purification system supported by the system  403  does not allow the user to proceed with treatment. This is achieved, in one embodiment, by suspending functioning of the pumps that propel fluids through the fluid circuits of the blood purification system  403 . Additionally, an audio/visual alarm may also be displayed to this effect. 
         [0069]    In another example, dialyzer cartridge  402  identified by the reader  401  may not be authentic as a result of which; the microprocessor would not allow functioning of the blood purification system of the system  403 . Thus, the e-lockout system  400  of the present invention prevents usage of the system  403  in case the disposable items  402  attached to the manifold  403  are in a compromised state. 
         [0070]    While there has been illustrated and described what is at present considered to be a preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made, and equivalents may be substituted for elements thereof without departing from the true scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the central scope thereof. Therefore, it is intended that this invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out the invention, but that the invention will include all embodiments falling within the scope of the appended claims.