Abstract:
Systems and methods handle air and rinsing fluid during fluid processing. The systems and methods eliminate air from a fluid processing system prior to, during, and after use. The systems and methods provide a connector assembly for establishing fluid flow from a fluid source. The connector assembly has discrete first and second passages that prevent communication between the fluid in first passage and the fluid in the second passage. Prior to system use, the connector assembly may be utilized in a priming function to remove residual air from a fluid circuit prior to use. The connector assembly may also be utilized after use to perform a rinse-back function.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a divisional of U.S. application Ser. No. 11/742,715, filed May 1, 2007, now U.S. Pat. No. 7,588,684, which is a continuation of U.S. application Ser. No. 10/772,888, filed Feb. 4, 2004, now U.S. Pat. No. 7,226,538, which is a divisional of U.S. application Ser. No. 09/905,171, filed Jul. 13, 2001, now abandoned, all of which are hereby incorporated by reference herein in their entireties. 
    
    
     FIELD OF THE INVENTION 
     The invention generally relates to fluid processing systems and methods. In particular, the invention relates to systems and methods that process blood or fluids that are introduced into the body, for example, during filtration, dialysis, or other diagnostic or therapeutic purposes. 
     BACKGROUND OF THE INVENTION 
     Systems are well known that process or treat blood or other fluids, and that return processed or treated blood or fluids to an individual. It is necessary to eliminate air from such systems prior to and during use, to avoid introduction of air into the individual undergoing treatment. Typically, drip chambers are used. It is also desirable, after use, to flush residual blood or fluid from the system, typically for return to the individual undergoing treatment. 
     There remains a demand for straightforward ways to handle air and to rinse residual blood or fluids from blood or fluid processing systems. 
     SUMMARY OF THE INVENTION 
     The invention provides systems and methods for handling air in a fluid processing circuit. The invention also provides systems and methods for rinsing or flushing residual fluids from a fluid processing circuit after processing is concluded. 
     One aspect of the invention provides systems and methods for priming a fluid circuit. The systems and methods couple a connector assembly to a fluid reservoir. The connector assembly comprises a first fluid passage and a second fluid passage. The systems and methods circulate fluid in the fluid circuit through the fluid reservoir, by conveying fluid into the inlet of the fluid circuit from the reservoir through the second fluid passage while conveying fluid from the outlet of the fluid circuit into the reservoir through the first fluid passage. During the circulation step, the systems and methods accumulate air residing in the fluid circuit in the fluid reservoir, thereby removing air from the fluid circuit. 
     In one embodiment, the systems and methods releasably couple the first fluid passage to the outlet of the fluid circuit, and also releasably couple the second fluid passage to the inlet of the fluid circuit. In one arrangement, the systems and methods couple the first and second passages together in a loop after the accumulating step. 
     In one embodiment, the systems and methods convey fluid into the fluid reservoir at a higher gravity height than fluid is conveyed from the fluid reservoir. 
     Another aspect of the invention provides systems and methods for both priming and flushing a fluid circuit. The systems and methods provide a connector assembly comprising a first fluid passage that is releasably coupled to an outlet of the fluid circuit and a second fluid passage that is releasably coupled to an inlet of the fluid circuit. The systems and methods couple the connector assembly to a fluid reservoir. The systems and methods prime the fluid circuit through the fluid reservoir by conveying fluid into the inlet of the fluid circuit from the reservoir through the second fluid passage while conveying fluid from the outlet of the fluid circuit into the reservoir through the first fluid passage. After the priming step, the systems and methods release the coupling between the connector assembly and the inlet and outlet of the fluid circuit, while keeping the connector assembly coupled to the fluid reservoir. The systems and methods then process a selected fluid using the fluid circuit. After the processing step, the systems and methods couple the inlet of the fluid circuit to the second fluid passage. The systems and methods then rinse residue of the selected fluid from the fluid circuit by conveying fluid into the inlet of the fluid circuit from the reservoir through the second fluid passage, while conveying the selected fluid residue from the outlet of the fluid circuit in a path that bypasses the reservoir. 
     In one embodiment, during the processing step, the first and second fluid passages are coupled together in a loop. 
     Another aspect of the invention provides a fluid processing apparatus comprising a fluid container, and a connector assembly coupled to the fluid container. The connector assembly includes a first fluid passage that is releasably coupled by a luer connector to an outlet of a fluid circuit. The connector assembly also includes a second fluid passage that does not communicate with the first fluid passage and that is releasably coupled by a luer connector to a inlet of the fluid circuit. In this arrangement, fluid can be circulated by the connector assembly through the fluid container in a loop that includes the fluid circuit to collect in the fluid source air residing in the fluid circuit. 
     Regarding any above-discussed aspect of the invention, the connector assembly can, in one embodiment, comprise a single connector body that includes both the first and second fluid passages. In one arrangement, the connector body includes a distal end having a taper to form a spike, which can be coupled to the fluid reservoir, e.g., by penetrating a port tube membrane. 
     Regarding any above-discussed aspect of the invention, the connector assembly can comprise, in another embodiment, a first connector body that includes the first fluid passage and a second connector body that includes the second fluid passage. In one arrangement, each of the first and second connector bodies includes a distal end having a taper to form a spike, which can be coupled to the fluid reservoir, e.g., by penetrating a port tube membrane. 
     Another aspect of the invention provides a dual lumen connector for coupling to a fluid source. The connector comprises a body in which there are first and second fluid passages that do not communicate with each other. A first assembly communicates with the first fluid passage and includes a first fitting to releasably couple the first fluid passage to an outlet of a fluid circuit. A second assembly communicates with the second fluid passage and includes a second fitting to releasably couple the second fluid passage to an inlet of the fluid circuit. Using the connector, fluid can be circulated through the fluid source in a loop that includes the fluid circuit to collect in the fluid source air residing in the fluid circuit. 
     The fluid circuit used in association with the invention in all of its various aspects can itself take various forms and functions. The fluid circuit can, for example, comprise at least a portion of a hemofiltration system, or a hemodialysis system, or a hemodiafiltration system, or a peritoneal dialysis system. 
     The invention makes possible the use of fluid circuits free of drip chambers, thereby minimizing the quantity of priming fluid discarded during priming. 
     Other features and advantages of the inventions are set forth in the following specification and attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of a generic fluid processing system; 
         FIG. 2 . is a schematic view of a priming system that can be used with the fluid processing system shown in  FIG. 1 , which includes a dual lumen connector assembly; 
         FIG. 3A  is an enlarged side sectional view of the dual lumen connector assembly that forms a part of the priming system shown in  FIG. 2 ; 
         FIG. 3B  is an enlarged side sectional view of the dual lumen connector assembly shown in  FIG. 3A  when performing a priming function; 
         FIG. 3C  is an enlarged side sectional view of the dual lumen connector assembly shown in  FIG. 3A  formed into a closed loop that preserves its sterility after performing the priming function shown in  FIG. 3B  and before performing a rinse-back function; 
         FIG. 4 . is a schematic view of a rinse-back system that can be used with the fluid processing system shown in  FIG. 1 , and which includes the same dual lumen connector assembly that previously performed the priming function shown in  FIG. 3B ; 
         FIG. 5 . is a schematic view of a system with a dual lumen connector assembly as shown in  FIG. 3A , which is supplied to an operator preconnected to a fluid circuit; 
         FIG. 6A  is a schematic view of an alternative fluid priming assembly comprising a priming container with integrally connected first and second tubing assemblies that can be used with the fluid processing system shown in  FIG. 1 ; 
         FIG. 6B  is a schematic view of a system formed after connecting the fluid priming assembly shown in  FIG. 6A  with the fluid circuit shown in  FIG. 1 ; 
         FIG. 7  is a schematic view of an alternative embodiment of a fluid priming assembly, which is supplied to an operator preconnected to a fluid circuit; and 
         FIG. 8  is a schematic view of a container that carries replacement fluid and that includes both an associated fluid priming assembly and replacement fluid inlet path. 
     
    
    
     The invention may be embodied in several forms without departing from its spirit or essential characteristics. The scope of the invention is defined in the appended claims, rather than in the specific description preceding them. All embodiments that fall within the meaning and range of equivalency of the claims are therefore intended to be embraced by the claims. 
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     I. System Overview 
       FIG. 1  schematically shows the components of a generic fluid processing system  10 . The system  10  has a first inlet  12  for receiving fluid and an outlet  14  for discharging fluid. A fluid circuit  16  is coupled between the first inlet  12  and the outlet  14 , through which the incoming fluid flows and is then discharged. The fluid circuit  16  processes the fluid in a desired manner and can be conventional. 
     The fluid circuit  16  may also include a second inlet  18  through which a processing fluid is introduced into the fluid circuit  16 . The processing fluid is drawn from a source  20 , which can be fluid containers or a sterile fluid generating source. The sterile fluid can be generated, e.g., by treating water from an external source, or by sterile filtering a fluid waste product of the fluid circuit  16  itself, e.g., as disclosed in application Ser. No. 09/027,301 filed Feb. 19, 1998 and entitled “Hemofiltration System Including Ultrafiltrate Purification and Reinfusion System,” which is incorporated herein by reference. 
     The fluid processing system  10  can take various forms. It can, for example, comprise a blood processing system for conducting hemofiltration, or hemodialysis, or hemodiafiltration. The system  10  can also comprise a peritoneal dialysis system. 
     As will be described herein for purpose of illustration, the system  10  forms a part of a hemofiltration system. The system receives through the first inlet  12  blood from an individual, e.g., through a suitable incoming blood line  22 , which can comprise an access site for withdrawing blood from an individual, e.g., by connection to an artery, a vein, or a fistula. An in-line pinch clamp  46  or the like can be provided in the blood line  22 . A pumping mechanism P in the fluid circuit  16  pumps the blood through a hemofilter HF, where toxins (WASTE) are removed. The treated blood is discharged through the outlet  14  for return to the circulatory system of the individual, e.g., through a suitable outgoing blood line  24 , which can comprise an access site for returning blood to an individual, e.g., typically by connection to a vein. An in-line pinch clamp  46  or the like can also be provided in the blood line  24 . 
     During hemofiltration, a replacement fluid is typically added to the treated blood through the second inlet  18 , to make up for the fluid lost during toxin removal. Typically, the replacement fluid is added in volumetric proportion to the amount of fluid removed from the blood. The replacement fluid is drawn from the source  20 , which communicates with to the second inlet  18 . 
     As is the case before using many fluid processing systems, it is necessary before conducting hemofiltration to remove residual air from the fluid circuit  16  and, after conducting hemofiltration, to rinse blood and residual fluid from the fluid circuit  16 . 
     Accordingly, the system  10  includes a fluid priming assembly  26  (shown in  FIGS. 2 ;  3 A/B/C; and  4 ). The purposes of the fluid priming assembly  26  are (1) to prime the system and thereby remove residual air from the fluid circuit  16  prior to use, and (2) to “rinse back” or flush residual blood from the fluid circuit  16  after use. 
     Further details of the fluid priming assembly  26  will now be described. 
     II. The Fluid Priming Assembly 
     A. Priming Function 
     Details of the fluid priming assembly  26  are illustrated in  FIGS. 2 ;  3 A/B/C; and  4 ). 
     As there shown, the fluid priming assembly  26  includes a connector  30  formed, e.g., from hard, medical grade plastic. There are two fluid passages (lumens)  36  and  38  (see  FIG. 3A ) formed in the body of the connector  30 . These passages  36  and  38  can be formed, e.g., by conventional molding techniques. These passages  36  and  38  are discrete, such that the second fluid passage  38  does not communicate with the first fluid passage  36  within the body of the connector  30 . 
     In use, the connector  30  is intended to be coupled in fluid communication with a container  32  of priming solution. The priming container  32  can comprise, e.g., flexible bag containing saline or other suitable priming solution. In use, the priming container  32  is positioned above the fluid circuit  16 . Alternatively, the processing fluid source  20  can also be used as the source of priming solution. 
     The connector  30  may be coupled to the priming container  32  in various conventional ways, e.g., through a luer fitting or by penetration of a port tube membrane  34 . In the illustrated embodiment (see  FIG. 3B ), the priming container  32  includes a port tube membrane  34 . In this arrangement, the tip end of the connector  30  is tapered to form a spike  56 , providing a configuration similar to vented-type spikes for rigid bottles. In the illustrated embodiment (see  FIG. 3A ), the opening  50  of the first fluid passage  36  into the container  32  is located closer to the high tapered end  54  of the spike  56  than the opening  52  of the second fluid passage  38  into the container  32 . Thus, the first fluid passage  36  enters the container  32  at a higher gravity position than the second fluid passage  38 . The benefits of this configuration will be discussed later. 
     The fluid priming assembly  26  includes a first flexible tubing assembly  40  (see  FIG. 3A ) coupled to the connector  30 . The first tubing assembly  40  communicates only with the first fluid passage  36 . The first tubing assembly  40  terminates with a connector  42  to releasably connect the first fluid passage  36  to the fluid circuit  16 . The connector  42  can take various forms, depending upon the configuration of the mating connector in the fluid circuit  16 . In the illustrated embodiment, the connector  42  comprises a male luer  58  with a removable female-to-female connector  60  carried by the male luer  58 . The removable connector  60  carried by the male luer  5 . 8  is adapted to be coupled to a mating male connector  62  on the outlet  14  of the fluid circuit (as  FIG. 2  shows). In use (see  FIG. 3B ), priming fluid and residual air in the fluid circuit  16  is pumped by way of the first tubing assembly  40 , into the first fluid passage  36  and into the priming container  32 . 
     The fluid priming assembly  26  includes a second flexible tubing assembly  44  (see  FIG. 3A ) coupled to the connector  30 . The second tubing assembly  44  communicates only with the second fluid passage  38 . The second tubing assembly  44  terminates with a connector  64  to releasably connect the second fluid passage  36  to the fluid circuit  16 . The connector  64  can take various forms, depending upon the configuration of the mating connector in the fluid circuit  16 . In the illustrated embodiment, the connector  64  comprises a female luer connector that is adapted to be coupled to a mating male connector  66  on the inlet  12  of the fluid circuit (see  FIG. 2 ). In use (see  FIG. 3B ), vented fluid (free of air) is conveyed by way of the second tubing assembly  44  into the fluid circuit  16 , from the priming container  32  into the second fluid passage  38 . 
     Desirably, the connectors  42  and  64  are configured to also enable their connection one to the other in a sterile fashion (see  FIG. 3C ). In this way, after disconnection from the fluid circuit  16 , the first and second tubing assemblies  40  and  44  can be coupled together to form a closed loop  68 , to maintain sterility after being used to perform a priming function, so that additional functions, e.g., a rinse-back function, can be performed using the same connector  30  and priming container  32 . Further details of this feature will be described later. 
     With the first and second tubing assemblies  40  and  44  coupled to the fluid circuit  16  in the manner shown in  FIG. 2 , the connector  30  forms a priming loop  70  that circulates the priming solution through both the priming container  32  and the fluid circuit  16 . Conventional pinch clamps  46  are provided on both the first tubing assembly  40  and the second tubing assembly  44 , as well as the inlet and outlet  12  and  14 . These pinch clamps  46  allow regulation and control of fluid flow through the priming loop  70  and fluid circuit  16 . 
     As  FIG. 3B  shows, priming solution is drawn (by the fluid circuit pump P in the inlet line  12 ) through the second tubing assembly  44  from the priming container  32  and into the fluid circuit  16 . Residual air occupying the fluid circuit  16  is displaced by the priming solution and returned with the priming solution through the first tubing assembly  40  back into the priming container  32 . Because the opening  50  of the first fluid passage  36  (conveying air and fluid into the container  32 ) is located at a higher gravity height than the opening  52  of the second fluid passage  38  (conveying fluid out of the container  32 ), air in the fluid outflow discharged by the first fluid passage  36  is not drawn or sucked into the fluid inflow entering the second fluid passage  38 . Instead, the air floats upward, away from the second fluid passage  38  and is collected in the air space  72  at the top of the container  32 . This permits the fluid circuit  16  to be primed with fluid contained in the priming container  32 , while virtually all air is expelled from the fluid circuit  16  and trapped in the air space  72  in the priming container  32 . This procedure removes all air from the system  10 . 
     The pump P may continue to operate in this fashion until steps are taken to begin fluid processing. For example, when the fluid circuit  16  is being used to conduct hemofiltration, the pump P can be operated to continuously recirculate the priming fluid from the container  32  through the circuit  16 . until the patient is available for attachment to the fluid circuit  16 . 
     In a preferred embodiment (see  FIG. 5 ), the fluid circuit  16  is supplied to the operator with the connector  30  releasably preconnected to the circuit  16  by the connectors  66 / 64  and  62 / 42 . In this arrangement, the connector  30  is enclosed in a sterile manner within a cap  80 , which maintains its sterility prior to use. When supplied to the operator, the pinch clamps  46  provided upstream and downstream of the connectors  66 / 64  and  62 / 42  are preferably open. 
     Priming of the fluid circuit  10  commences with the removal of the cap  80  and coupling the connector  30  to the priming container  32  (see  FIG. 2 ). The pump P is operated in a forward flow condition to draw fluid from the priming container  32  and push air into the priming container  32  (as shown in  FIG. 3B ). The priming solution is circulated in this manner in the loop  70  until priming solution fills the fluid circuit  16  and all air is expelled and collected in the air space  72  at the top of the priming container  32 . 
     A flow restrictor  74  can be placed in the first tubing assembly  40  or in the first fluid passage  36 . The flow restrictor  74  helps to create a positive back pressure at the outlet  14 , to facilitate complete priming of the hemofilter HF (or other blood processing device the system  10  may incorporate). 
     Once the fluid circuit  16  is primed, operation of the pump P is terminated, and all pinch clamps  46  are closed. The operator disconnects the connector  62  from the connector  42 . The free connector  62  on the outlet  14  is, in turn, coupled to the outgoing fluid access line  24 . While the connection of the outlet  14  to the outgoing fluid access line  24  occurs, the female-to-female connector  60  is left attached to the male luer  58  of the connector  42 , to serve as a cap for the male luer  58 . As a cap, the connector  60  covers the male luer  58  on the first tubing assembly  40 , to maintain its sterility while the inlet  12  of the fluid circuit  16  is disconnected from the second tubing assembly  44 . 
     To disconnect the inlet  12  of the fluid circuit  16  from the second tubing assembly  44 , the operator disconnects the connector  66  from connector  64 . The free connector  66  on the inlet  12  is, in turn, coupled to the incoming fluid access line  22 . The system  10  is now in the condition for use shown in  FIG. 1 . 
     The female-to-female connector  60  is now removed to expose the male luer  58  of the first tubing assembly  40 . The connector  60  can now be discarded. The male luer  58  can then be connected with the female luer  64  on the second tubing assembly  44  (see  FIG. 3C ). The closed loop  68  is thereby formed between the first and second tubing assemblies  40  and  44 , through the priming container  32 , to maintain sterility within the connector  30  and tubing assemblies  40  and  44  until the rinse-back function is performed. When the closed loop  68  is formed, the clamps  46  in the tubing assemblies  40  and  44  may be closed. 
     The clamps  46  on inlet and outlet lines  12  and  14  and the incoming and outgoing fluid access lines  22  and  24  can be opened. operation of the pump P begins, and the primed fluid circuit  16  processes blood and fluid in the desired manner (e.g., hemofiltration). 
     B. Rinse-Back Function 
     The rinse-back function is performed at the end of the blood processing session. The rinse-back function is illustrated in  FIG. 4 . 
     After blood processing, the outgoing fluid access assembly  24  is left connected to the outlet  14 , to return residual fluid from the fluid circuit  16  to the individual during the rinse-back function. The operator disconnects the male luer  58  on the first tubing assembly  40  from the female luer  64  on the second tubing assembly  44 , to interrupt the loop  58 . The clamps  46  on the incoming fluid access assembly  22  and inlet  12  are closed. The incoming fluid access assembly  22  is disconnected from the inlet  12 . The female luer  64  of the second tubing assembly  44  is coupled to male luer  66  on the inlet  12 . 
     The pinch clamps  46  in the second tubing assembly  44  and the inlet  12  are opened (the pinch clamp  46  on the first tubing assembly  40  remains closed). Subsequent operation of the pump P draws priming solution from the container  32  into and through the fluid circuit  16 . In this process, residual blood remaining in the fluid circuit  16  is effectively rinsed or flushed from the circuit  16  and ultimately returned to the individual through the outgoing fluid access assembly  24 . This reduces the amount of blood loss by the individual. 
     At the end of the rinse-back function, the operator disconnects the outlet  14  from the outgoing fluid access assembly  24 . The system  10 , which includes the fluid circuit  16  connected by the connector  30  to the priming container  32 , can now be discarded as a unit. 
     The arrangement as described performs both a priming function and a rinse back function using the same connector assembly and the same source of solution. 
     III. Other Embodiments 
     The fluid priming assembly  26  can be constructed in various alternative ways. 
     For example, as shown in  FIG. 6A , a fluid priming assembly  28  comprises the priming container  32  that is supplied to the operator with the first and second tubing assemblies  40  and  44  attached as individual lengths of flexible tubing integrally coupled directly to priming container  32 , without use of the intermediate dual lumen connector  30 . Each tubing length  40  and  44  includes its own luer connector, respectively  42  and  64 , and an upstream pinch clamp  46 , which is closed at the time it is supplied to the operator. At time of use (as  FIG. 6B  shows), the first tubing assembly connector  42  can be coupled the connector  62  of the outlet  14 , and the second tubing assembly connector  64  is coupled to the connector  66  of the inlet  12 . Alternatively, the container  32  with preconnected first and second tubing assemblies can be supplied to the operator releasably preconnected to the fluid circuit  16  in the manner shown in  FIG. 6B . 
     Once the components are assembled as shown in  FIG. 6B , the pinch clamps  46  can be opened and the pump P operated in the manner as previously discussed, to draw fluid from the priming container  32  and push air into the priming container  32 , thereby priming the fluid circuit  16 . Subsequent manipulation of the first and second tubing assemblies  40  and  44  and priming container  32 , to enable fluid processing in the fluid circuit  16  after priming, as well as to conduct a rinse back function after fluid processing, is carried out in the same manner as discussed with regard to the configuration shown in  FIG. 5 . 
     Alternatively, as shown in  FIG. 7 , a fluid priming assembly  28  comprises the first and second tubing assemblies  40  and  44  taking the form of individual lengths of flexible tubing coupled directly to priming container  32  at time of use by means of separate connectors  82  and  84 . The connectors  82  and  84  can take the form of luer fittings or, as shown in  FIG. 7 , spikes that penetrate separate port tube membranes  86  on the priming container  32 . As  FIG. 7  shows, the two connectors  82  and  84  (desirably enclosed within caps  80 ) can be supplied to the operator releasably preconnected to the circuit  16  by the connectors  66 / 64  and  62 / 42 , in the same manner as the single connector  30  shown in  FIG. 5 . After coupling the dual connectors  82  and  84  to the priming container  32  at time of use (as indicated by arrows in  FIG. 7 ), the manipulation of the first and second tubing assemblies  40  and  44  in  FIG. 7  to carry out the priming and rinse back functions is the same as discussed with regard to the single connector configuration shown in  FIG. 5 . 
     In another alternative embodiment (see  FIG. 8 ), the fluid that the container  32  carries can comprise the replacement fluid that is added to make up for fluid lost during toxin removal. In this arrangement, the inlet  18  includes a connector  90  that releasably couples to a mating connector  88  carried by a third tubing assembly  92 , which is itself coupled directly to the container  32 . The third tubing assembly  92  can be coupled to the container  32  in the same manner as the first and second tubing assemblies  40  and  44 , i.e., either by integral coupling or by use of instant-of-use luer or spike connectors. In this arrangement, the tubing assemblies  40  and  44  convey the replacement fluid to perform a priming and rinse back function at the beginning and end of fluid processing, as previously described, while the third tubing assembly  92  conveys replacement fluid during fluid processing. In this arrangement, the container  32  can comprise a container prefilled with replacement fluid, or it can comprise a reservoir that receives replacement fluid from a sterile fluid generating source during fluid processing. The sterile fluid can be generated, e.g., by treating water from an external source or (as  FIG. 8  shows) by sterile filtering the fluid waste product of the fluid circuit  16  itself in a replacement fluid generation device  94 , e.g., of a type disclosed in application Ser. No. 09/027,301 filed Feb. 19, 1998 and entitled “Hemofiltration System Including Ultrafiltrate Purification and Reinfusion System,” which is incorporated herein by reference. 
     Features and advantages of the invention are set forth in the following claims.