WO2017030860A1

WO2017030860A1 - Fluid bag with controlled thickness to volume ratio and systems using same

Info

Publication number: WO2017030860A1
Application number: PCT/US2016/046293
Authority: WO
Inventors: Douglas C. Johnson
Original assignee: Gambro Lundia AB
Current assignee: Gambro Lundia AB
Priority date: 2015-08-20
Filing date: 2016-08-10
Publication date: 2017-02-23
Anticipated expiration: 2018-02-20

Abstract

Fluid bags that can be used to collect and/or dispense liquid in connection with extracorporeal blood treatment systems (e.g., systems configured to perform hemodialysis, hemodiafiltration, hemofiltration, peritoneal dialysis, etc.) are described herein. Extracorporeal blood treatment systems including one or more such fluid bags are also described herein. The fluid bags and systems using them as described herein may be configured such that the thickness of the fluid bag, when at or near maximum capacity, may be reduced as compared to a conventional fluid bag of the same capacity

Description

FLUID BAG WITH CONTROLLED THICKNESS TO VOLUME RATIO AND

SYSTEMS USING SAME

CROSS-REFERENCE

This application claims the benefit of U.S. Provisional Application Serial No. 62/207,772, filed 20 August 2015, which is incorporated herein by reference in its entirety.

Fluid bags that can be used to collect and/or dispense liquid in connection with extracorporeal blood treatment systems (e.g., systems configured to perform hemodialysis, hemodiafiltration, hemofiltration, peritoneal dialysis, etc.) are described herein.

Extracorporeal blood treatment systems including one or more such fluid bags are also described herein.

Fluid bags may be used a source of fluids used for hemodialysis, hemodiafiltration, hemofiltration and/or peritoneal dialysis, as well as the collection of waste fluids generated during those and other therapeutic medical processes.

In many systems in which fluid bags are used as a source or for the collection of medical fluids, the fluid bags are suspended below a housing, typically in close proximity to each other so as to reduce the overall size of the system. In some systems, the waste liquids (e.g. used dialysate, ultrafiltrate, etc.) collected from a medical process can be delivered directly to a sewage system. In some apparatus, however, the waste liquids are collected in a container such as, e.g., a fluid bag, connected to the system.

Whether the fluid bags used in connection with systems such as those described herein are used as a source of fluid or for the collection of fluid, the volume of fluid contained by those fluid bags may, as described in, e.g., US Patent Application Publication No. US 2007/0265594, limit the uninterrupted operation time for the processes performed by the systems due to the need to change fluid bags that are empty (when those bags are used as a source of fluid for the process) or that have reached their capacity (when those bags are used to collect waste fluids from the process).

SUMMARY

In one or more embodiments, the fluid bags described herein may be suspended from an extracorporeal blood treatment system in relatively close proximity to each other. When the bags are at or close to their maximum capacity (e.g., at the start of a process in the case of fluid bags used as a source of fluid) or after some time during operation of the process (e.g., in the case of fluid bags used to collect waste fluids), the thickness of the fluid bags may be large enough such that adjacent pairs of fluid bags may potentially be in physical contact with each other.

Physical contact between fluid bags may, however, be problematic in

extracorporeal blood treatment systems that are, at least in part, controlled based on the weight of liquid in one or more of the fluid bags used in connection with the systems. Physical contact between adjacent fluid bags may, for example, negatively impact the accuracy of any weight measurement on the fluid bags that are in contact with each other.

The fluid bags and systems using them as described herein may, in one or more embodiments, be configured such that the thickness of the fluid bag, when at or near maximum capacity, may be reduced as compared to a conventional fluid bag of the same capacity. That reduced thickness may allow larger capacity fluid bags to be used in a system which may, in turn, provide for longer periods of an interrupted operation of the systems described herein.

In a first aspect, one or more embodiments of a fluid bag configured to retain liquid as described herein includes a first sheet and a second sheet; a perimeter seal that defines an interior volume of the fluid bag between interior surfaces of the first and second sheets, wherein the first sheet is attached to the second sheet along the perimeter seal, and wherein the perimeter seal comprises a top portion, a bottom portion located opposite from the top portion, and two opposing side portions extending from the top portion of the perimeter seal to the bottom portion of the perimeter seal; connection structure located proximate the top portion of the perimeter seal, wherein the connection structure is configured to suspend the fluid bag below a connector such that the bottom portion of the perimeter seal is located below the top portion as the fluid bag fills with liquid when suspended from the connection structure; a bag length measured along a first straight line extending across the first sheet between the bottom portion and the top portion of the perimeter seal, wherein the bag length is measured when no liquid is located in the fluid bag and the first sheet is lying on a flat horizontal surface, and wherein the first straight line extends through a geometric center of a two-dimensional geometric figure defined by the perimeter seal when no liquid is located in the fluid bag and the first sheet is lying on a flat horizontal surface; an upper bag area on the interior surface of the first sheet, wherein the upper bag area is defined by a second straight line intersecting the first straight line at a midpoint of the first straight line, the top portion of the perimeter seal, and the opposing side portions of the perimeter extending from the second straight line to the top portion of the perimeter seal, and wherein the second straight line extends between the opposing side portions of the perimeter seal and is oriented transverse to the first straight line; and a lower bag area on the interior surface of the first sheet, wherein the lower bag area is defined by the second straight line, the bottom portion of the perimeter seal, and the opposing side portions of the perimeter extending from the second straight line to the bottom portion of the perimeter seal; wherein the lower bag area is 80% or less of the upper bag area when no liquid is located in the fluid bag and the first sheet is lying on a flat horizontal surface.

In one or more embodiments of a fluid bag according to the first aspect as described herein, the lower bag area is 70% or less of the upper bag area.

In one or more embodiments of a fluid bag according to the first aspect as described herein, the lower bag area is 60% or less of the upper bag area.

In one or more embodiments of a fluid bag according to the first aspect as described herein, the lower bag area is 50% or less of the upper bag area. In one or more embodiments of a fluid bag according to the first aspect as described herein, the fluid bag comprises a bag width measured across the first sheet between the two opposing side portions of the perimeter seal in a direction parallel to the second straight line, wherein the bag width is measured when no liquid is located in the fluid bag and the first sheet is lying on a flat horizontal surface, and wherein the bag width decreases when moving along the first straight line towards the bottom portion of the perimeter seal in at least a portion of the lower bag area.

In one or more embodiments of a fluid bag according to the first aspect as described herein, the fluid bag comprises a bag width measured across the first sheet between the two opposing side portions of the perimeter seal in a direction parallel to the second straight line, wherein the bag width is measured when no liquid is located in the fluid bag and the first sheet is lying on a flat horizontal surface, and wherein the bag width in at least a portion of the lower bag area decreases when moving along the first straight line towards the bottom portion of the perimeter seal; and further wherein the bag width in the lower bag area increases after decreasing when continuing to move along the first straight line towards the bottom portion of the perimeter seal. In one or more

embodiments, the fluid bag comprises a minimum bag width in the lower bag area, and further wherein the minimum bag width is less than the bag width at any location in the upper bag area. In one or more embodiments, the fluid bag comprises an upper maximum bag width in the upper bag area and a minimum bag width in the lower bag area, and further wherein the minimum bag width is 90% or less of the maximum bag width.

In a second aspect, one or more embodiments of a fluid bag configured to contain liquid as described herein includes a first sheet and a second sheet; a perimeter seal that defines an interior volume of the fluid bag between interior surfaces of the first and second sheets, wherein the first sheet is attached to the second sheet along the perimeter seal, and wherein the perimeter seal comprises a top portion, a bottom portion located opposite from the top portion, and two opposing side portions extending from the top portion of the perimeter seal to the bottom portion of the perimeter seal; connection structure located proximate the top portion of the perimeter seal, wherein the connection structure is configured to suspend the fluid bag below a connector such that the bottom portion of the perimeter seal is located below the top portion as the fluid bag fills with liquid when suspended from the connection structure; a bag length measured along a first straight line extending across the first sheet between the bottom portion and the top portion of the perimeter seal, wherein the bag length is measured when no liquid is located in the fluid bag and the first sheet is lying on a flat horizontal surface, and wherein the first straight line extends through a geometric center of a two-dimensional geometric figure defined by the perimeter seal when no liquid is located in the fluid bag and the first sheet is lying on a flat horizontal surface; a bag width measured along a set of second straight lines extending across the first sheet between the two opposing side portions of the perimeter seal in a direction transverse to the first straight line, wherein the bag width is measured when no liquid is located in the fluid bag and the first sheet is lying on a flat horizontal surface; wherein the bag width decreases when moving along at least a portion of the first straight line from an upper location on the first straight line towards the bottom portion of the perimeter seal, wherein the upper location is located on the first straight line at a position that is 20% or more of the bag length from an intersection of the first straight line and the bottom portion of the perimeter seal.

In one or more embodiments of a fluid bag according to the second aspect as described herein, the position of the upper location is 30% or more of the bag length from the intersection of the first straight line and the bottom portion of the perimeter seal.

In one or more embodiments of a fluid bag according to the second aspect as described herein, the position of the upper location is 40% or more of the bag length from the intersection of the first straight line and the bottom portion of the perimeter seal.

In one or more embodiments of a fluid bag according to the second aspect as described herein, the position of the upper location is 70% or less of the bag length from the intersection of the first straight line and the bottom portion of the perimeter seal.

In one or more embodiments of a fluid bag according to the second aspect as described herein, the position of the upper location is 60% or less of the bag length from the intersection of the first straight line and the bottom portion of the perimeter seal.

In one or more embodiments of a fluid bag according to the second aspect as described herein, the position of the upper location is 50% or less of the bag length from the intersection of the first straight line and the bottom portion of the perimeter seal. In one or more embodiments of a fluid bag according to the second aspect as described herein, the bag width increases when moving along a portion of the first straight line from a lower location on the first straight line towards the bottom portion of the perimeter seal, wherein the lower location is located between the upper location and the bottom portion of the perimeter seal such that the bag width decreases and then increases when moving along the first straight line from the upper location towards the bottom portion of the perimeter seal. In one or more embodiments, the fluid bag comprises a minimum bag width below the upper location at a position along the first straight line that is 10% or more of the bag length above the intersection of the first straight line and the bottom portion of the perimeter seal, wherein the fluid bag comprises a maximum bag width above the upper location, wherein the maximum bag width is greater than the minimum bag width and is located along an upper section of the first straight line extending from the upper location to the top portion of the perimeter seal, and wherein the minimum bag width is located along a lower section of the first straight line extending from the upper location to the intersection of the first straight line and the bottom portion of the perimeter seal. In one or more embodiments, the minimum bag width is 70% or less of the maximum bag width. In one or more embodiments, the minimum bag width is 60% or less of the maximum bag width. In one or more embodiments, the minimum bag width is 20% or more of the maximum bag width. In one or more embodiments, the minimum bag width is 30% or more of the maximum bag width.

In a third aspect, one or more embodiments of a treatment system as described herein may include a pump configured to move fluid through the treatment system; and a connector configured to suspend a fluid bag as described herein below the pump.

In one or more embodiments of a treatment system as described herein, the system may include an apparatus configured to perform hemodialysis, hemodiafiltration, hemofiltration, or peritoneal dialysis; wherein the fluid bag suspended below the pump is in fluid communication with the apparatus such that fluid leaving the apparatus is collected in the fluid bag.

In one or more embodiments of a treatment system as described herein, the system may include a plurality of connectors configured to suspend a plurality of the fluid bags as described herein below the pump, wherein each connector of the plurality of connectors is configured to suspend one fluid bag of the plurality of fluid bags. In one or more embodiments, two or more fluid bags of the plurality of fluid bags are suspended below the pump such that the first and second sheets of the two or more fluid bags are aligned with each other.

As used herein and in the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a" or "the" component may include one or more of the components and equivalents thereof known to those skilled in the art. Further, the term "and/or" means one or all of the listed elements or a combination of any two or more of the listed elements.

It is noted that the term "comprises" and variations thereof do not have a limiting meaning where these terms appear in the accompanying description. Moreover, "a," "an," "the," "at least one," and "one or more" are used interchangeably herein.

Where used herein, the terms "top" and "bottom" are used for reference relative to the direction of gravity where gravitational force vectors extend from the top towards the bottom of a fluid bag when the fluid bag is suspended and used to collect fluid.

The above summary is not intended to describe each embodiment or every implementation of the fluid bags and systems described herein. Rather, a more complete understanding of the invention will become apparent and appreciated by reference to the following Description of Illustrative Embodiments and claims in view of the

accompanying figures of the drawing.

BRIEF DESCRIPTION OF THE VIEWS OF THE DRAWING FIG. 1 depicts one illustrative embodiment of an extracorporeal blood treatment system having four conventional fluid bags suspended below a housing of the system.

FIG. 2 depicts the illustrative embodiment of extracorporeal blood treatment system of FIG. 1 with four fluid bags as described herein suspended below the housing of the system.

FIGS. 3-6 depicts illustrative embodiments of fluid bags as described herein. FIG. 7 is a perspective view of another illustrative embodiment of an

extracorporeal blood treatment system with two fluid bags suspended or in the process of being suspended below the system.

FIG. 8 is a perspective view of one illustrative embodiment of a connector that may be used to suspend fluid bags as described herein below an extracorporeal blood treatment system.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In the following description of illustrative embodiments, reference is made to the accompanying figures of the drawing which form a part hereof, and in which are shown, by way of illustration, specific embodiments. It is to be understood that other

embodiments may be utilized and structural changes may be made without departing from the scope of the present invention.

Referring to FIG. 1, one illustrative embodiment of an extracorporeal blood treatment system 10 is depicted. The system 10 includes a housing 12 and one or more pumps 14 used to move liquids through the system as part of a treatment process.

Although the pumps 14 are depicted in the form of peristaltic pumps, the pumps used in the extracorporeal blood treatment system described herein may be provided in a variety of alternative forms, e.g., piston pumps, diaphragm pumps, etc.

The extracorporeal blood treatment system 10 also includes, in one or more embodiments, a display 16 used to convey information to a user. The display 16 may also serve as an input device if, e.g., the display 16 is in the form of a touchscreen. Also, although the display 16 is depicted as be located in the housing 10, in one or more alternative embodiments, the display 16 may be separate from the housing 12 of the extracorporeal blood treatment system 10.

The extracorporeal blood treatment system 10 also includes scales 18, each of which is configured to hold and weigh a fluid bag 20. The scales 18 are positioned below a bottom end 17 of the housing 10, at least in part because the fluid bags 20 are typically attached to and hang from the scales 18. Although the depicted embodiment of extracorporeal blood treatment system 10 includes four scales 18 and associated fluid bags 20, alternative embodiments of an extracorporeal blood treatment system as described herein may include as few as two scales 18 and associated fluid bags 20. In still other variations, one of the scales 18 may be used to hold and weigh two or more fluid bags 20 rather than a single fluid bag 20 as depicted in FIG. 1.

The fluid bags 20 may be in the form of, e.g., flexible polymeric bags configured to hold liquids that are either used by or collected during a treatment process as the extracorporeal blood treatment system is operating. In one or more embodiments using conventional fluid bags that are at or near their maximum capacity, one or more pairs of adjacent fluid bags 20 may expand sufficiently such that the fluid bags 20 contact each other as depicted in, e.g., FIG. 1. In extracorporeal blood treatment systems in which control over the process being performed by the system relies on accurate measurements of the weight of fluid in one or more of the fluid bags 20, that contact between fluid bags 20 can result in errors in the weight measurements of the fluid bags 20 that are in contact with each other. To avoid that problem, users typically monitor the capacity of fluid bags 20 such that contact between the bags is limited or avoided. The result, however, is that the uninterrupted time over which a process may be performed may be reduced by the need to avoid contact between fluid bags 20.

As discussed herein, one or more embodiments of the fluid bags described herein may be constructed such that the thickness of the fluid bag, when at or near maximum capacity, may be reduced as compared to a conventional fluid bag of the same capacity. That reduced thickness may allow larger capacity fluid bags to be used in a system which may, in turn, provide for longer periods of an interrupted operation of the systems described herein.

One exemplary embodiment of an extracorporeal blood treatment system 10 using one or more fluid bags 120 as described herein is depicted in FIG. 2. The components of the system 10 such as the housing 12, one or more pumps 14, display 16, housing bottom 17, and scales 18 may, in one or more embodiments, be exactly the same as those used in connection with conventional fluid bags 20 as depicted in FIG. 1. Because fluid bags 120 as described herein have a reduced thickness as compared to conventional fluid bags containing the same volume of fluid, contact between adjacent pairs of the fluid bags 120 may be limited or prevented even when the fluid bags 120 as described herein are at or near their maximum capacity. Although the extracorporeal blood treatment system 10 is depicted as employing four fluid bags 120 as described herein, in one or more alternative embodiments, a system 10 may use only one of the fluid bags described herein or any selected number of fluid bags as described herein, e.g., two, three, five, etc.

The illustrative embodiments of fluid bags 120 as depicted in FIG. 2 are viewed along an edge of the bag such that the thickness of the bag when containing fluid is illustrated. One illustrative embodiment of a fluid bag 120 taken from a side (left or right) of the housing 12 of the extracorporeal blood treatment system 10 is depicted in FIG. 3. In one or more embodiments, the fluid bags described herein are constructed of a first sheet 121 and a second sheet 122 that are attached to each other about a perimeter seal 130. The first sheet 121 and second sheet 122, along with the perimeter seal 130, define an interior volume 123 (see, e.g., FIG. 2) of the fluid bag 120 between interior surfaces of the first and second sheets 121 and 122, with liquid located within the fluid bag 120 being located in the interior volume 123 between the interior surfaces of the first and second sheets 121 and 122.

The perimeter seal 130 may, in one or more embodiments, include a top portion 132, two opposing side portions 134 and a bottom portion 136. The two opposing side portions 134 extend from the top portion 132 of the perimeter seal 130 to the bottom portion 136 of the perimeter seal 130 on opposite sides of the first sheet 121 of the fluid bag 120.

In one or more embodiments, the body of the fluid bags described herein may be constructed of polymeric sheet material such as, e.g. polyvinyl chloride ((PVC), ethylene- vinyl acetate (EVA), etc. of a thickness suitable to support the weight of the fluid bags when at capacity. The perimeter seals may be formed by any suitable technique or combination of techniques, e.g., thermal welding, ultrasonic welding, chemical welding, clamps, frames, etc. In one or more embodiments, one or more portions of the fluid bags may be constructed of other than sheet materials, e.g., the connection structure 124 (more completely described below) may be constructed of material that is other than sheet material, e.g., bar stock, rods, etc.

In one or more embodiments, the bottom portion 136 of the perimeter seal 130 may include a straight inner edge such as is depicted in connection with fluid bag 120 between ports 126 (which are described below). As a result, side portions 134 of perimeter seal 130 may be described as extending to the opposite ends of the straight inner edge of the bottom portion 136 of the perimeter seal 130. In other alternative embodiments, the bottom portion 136 may be a single point where, for example, the opposing side portions 134 of the perimeter seal 130 are continuously curved such that the bottom portion 136 has no effective length and is, rather, a single point at which the opposing side portions 134 of the perimeter seal 130 meet. In other words, the bottom portion 136 of the perimeter seal 130 may be described as that portion of the perimeter seal 130 along which liquid would initially collect under the force of gravity when the fluid bag 220 is in use on an extracorporeal blood treatment system.

In the illustrative embodiment depicted in FIG. 3, access to the interior volume 123 of the fluid bag 120 may be had using one or more ports 126. Although the illustrative embodiment of fluid bag 120 includes three ports 126 (one along the top portion 132 of the perimeter seal 130 and two located in the bottom portion 136 of the perimeter seal 130), fluid bags as described herein may include any suitable number of ports through which fluid may be delivered into or removed from the interior volume 123 of the fluid bag 120. Furthermore, although the ports 126 may, in the illustrative embodiment of fluid bag 120, extend through the perimeter seal 130, in one or more alternative embodiments one or more ports may be positioned through one or both of the sheets 121 and 122 forming a fluid bag as described herein. In addition, although the ports 126 are depicted in the top portion 132 or the bottom portion 136 of the perimeter seal 130, one or more ports providing access to the interior volume of a fluid bag as described herein may be located in any suitable location or locations.

Another feature depicted in FIG. 3 in connection with the illustrative embodiment of fluid bag 120 is a connection structure 124 located proximate the top portion 132 of the perimeter seal 130. The connection structure 124 is, in one or more embodiments, configured to suspend the fluid bag 120 below a connector (not shown) that is operably connected to a scale used in an extracorporeal blood treatment system as described herein. When suspended below a connector by the connection structure 124, the bottom portion 136 of the perimeter seal 130 is located below the top portion 132 of the perimeter seal 130 as the fluid bag 120 fills with liquid during a process being performed by an extracorporeal blood treatment system to which the fluid bag 120 is connected by one or more fluid lines.

In the depicted illustrative embodiment, the connection structure 124 is in the form of three apertures that cooperate with structures on a connector as described herein to retain the fluid bag 120 on a scale of an extracorporeal blood treatment system. In one or more embodiments, the specific number of apertures may be varied depending on the configuration of a connector to which the connection structure 124 of the fluid bag 120 is to be connected. For example, in one or more alternative embodiments as few as one aperture may be used while in still other alternative embodiments, to, for, or more apertures may be provided form the connection structure of a fluid bag as described herein.

Furthermore, although the depicted illustrative embodiment of connection structure 124 is in the form of apertures, many other connection structures may be used including, e.g., hooks, loops, clamps, etc., all of which are preferably configured to suspend a fluid bag as described herein below a connector of a scale on an extracorporeal blood treatment system. As a result, the connection structure may take any suitable form depending on the form of a connector associated with a scale of an extracorporeal blood treatment system with which the fluid bag is to be used to collect and/or deliver fluid.

The shape of the first and second sheets and the associated perimeter seal connecting those sheets are selected to provide the reduced thickness as compared to a fluid bag of conventional shape and similar capacity as described herein. In the illustrative embodiment of fluid bag 120, the first sheet 121 is depicted and the shape of the fluid bag 120 will be described with reference to the first sheet 121 and the perimeter seal 130 extending around the perimeter of the first sheet 121 (with the understanding that the second sheet 122 is located directly behind the first sheet 121 in the view of FIG. 3).

Further, the first sheet 121 is depicted in FIG. 3 as if it were lying on a flat horizontal surface with no liquid located in the fluid bag 120. It is in this condition that the shapes of one or more embodiments of the fluid bags described herein can be most accurately described.

With reference to FIG. 3, the illustrative embodiment of fluid bag 120 includes a bag length BL that can be measured along a first straight line 140 when no liquid is located in the fluid bag 120 and the first sheet 121 is lying on a flat horizontal surface. The first straight line 140 extends across the first sheet 121 between the top portion 132 and the bottom portion 136 of the perimeter seal 130. In the depicted embodiment, the first straight line 140 intersects with the inner edge of the top portion 132 of the perimeter seal 130 at intersection point 141 and the inner edge of the bottom portion 136 of the perimeter seal 130 at intersection point 142. In other words, the bag length BL can, in the depicted illustrative embodiment of fluid bag 120, be described as being the distance between intersection points 141 and 142 along first straight line 140.

In one or more embodiments, the first straight line 140 extends through a geometric center 131 of the two dimensional geometric figure defined by the perimeter seal 130 (again, when no liquid is located in the fluid bag 120 and the first sheet 121 is lying on a flat horizontal surface). In particular, the two dimensional geometric figure defined by the perimeter seal 130 is defined by an interior edge of the perimeter seal 130, i.e., the edge of the perimeter seal 130 that defines the interior volume 123 of the fluid bag 120.

In one or more embodiments, the first straight line 140 is further positioned and oriented such that the bag length BL is a minimum bag length for the fluid bag 120. In other words, although the first straight line 140 is depicted as being generally vertical with respect to the top portion 132 and bottom portion 136 of the perimeter seal 130, in one or more alternative embodiments a first straight line along which a bag length measurement may be obtained may be skewed (i.e., not vertical) relative to a vertical axis that would otherwise be defined between the top portion 132 and the bottom portion 136 of the perimeter seal 130.

In one or more embodiments of fluid bags as described herein such as the illustrative embodiment of fluid bag 120, the fluid bag 120 may be described as having an upper bag area 152 and a lower bag area 154. The upper bag area 152 may be described as being found on the interior surface of the first sheet 121 and separated from the lower bag area 154 (which is also found on the interior surface of the first sheet 121) by a second straight line 144 that intersects the first straight line 140 at a midpoint 143 of the first straight line 140 and extends between the opposing side portions 134 of the perimeter seal 130 between intersection points 145 and 146. The midpoint 143 of the first straight line 140 is measured between intersection points 141 and 142 of the straight line 140 between the top portion 132 and the bottom portion 136 of the perimeter seal 130. In one or more embodiments, the second straight line 144 may be oriented transverse to the first straight line 140.

As a result, the upper bag area 152 may be described as being defined by the second straight line 144, the top portion 132 of the perimeter seal 130 and the opposing side portions 134 of the perimeter seal 130 that extend from the second straight line 144 to the top portion 132 of the perimeter seal 130. In particular, the segments of the opposing side portions 134 of the perimeter seal 130 may extend towards the top portion 132 of the perimeter seal 130 from intersection points 145 and 146, where the intersection points 145 and 146 are the points at which the second straight line 144 intersects an interior edge of each of the opposing side portions 134 of the perimeter seal 130.

The lower bag area 154 may also be described as being found on the interior surface of the first sheet 121 and separated from the upper bag area 152 by the second straight line 144. The lower bag area 154 may further be described as being defined by the second straight line 144, the bottom portion 136 of the perimeter seal 130 and the opposing side portions 134 of the perimeter seal 130 that extend from the second straight line to the bottom portion 136 of the perimeter seal 130. In particular the segments of the opposing side portions 134 of the perimeter seal may extend towards the bottom portion 132 of the perimeter seal 130 from the intersection points 145 and 146 as described herein.

In one or more embodiments of fluid bags for use in extracorporeal blood treatment systems as described herein that can be characterized as having upper and lower bag areas as described herein, the lower bag area may be 80% or less of the upper bag area, again, where no liquid is located in the fluid bag and the sheet on which the upper and lower bag areas are defined is lying on a flat horizontal surface. Providing a fluid bag in which the lower bag area of the sheets used to define the interior volume of the fluid bag is smaller than the upper bag area may, in one or more embodiments, force more of the liquid in a fluid bag towards the top portion of the perimeter seal of any such fluid bag. Doing so may limit the thickness of the fluid bag within the lower bag area as compared to conventional fluid bags. In one or more alternative embodiments, the lower bag area may be 70% or less of the upper bag area, 60% or less of the upper bag area, or even 50% or less of the upper bag area. In one or more embodiments of the fluid bags as described herein, the fluid bags may be characterized in terms of bag width, where the bag width is measured across the first sheet of the bag between the two opposing side portions of the perimeter seal in a direction parallel to the second straight line. With reference to the illustrative embodiment of fluid bag 120 as depicted in FIG. 3, the bag width BW may be described as being measured across the first sheet between the two opposing side portions 134 of the perimeter seal 130 in a direction parallel to the second straight line 144. Again, the bag width is measured when no liquid is located in the fluid bag 120 and the first sheet 121 is lying on a flat horizontal surface. In one or more embodiments, the bag width decreases when moving along the first straight line 140 towards the bottom portion 136 of the perimeter seal 130 in at least a portion of the lower bag area 154. This concept is illustrated in connection with the illustrative embodiment of fluid bag 120 with reference to the decreasing bag widths BW1 and BW2, where BW2 is closer to the bottom portion 136 of the perimeter seal and shorter than BW1.

The fluid bags described herein may, in one or more embodiments, be characterized in terms of bag width relative to a selected location along the first straight line defining the bag length BL. In one or more embodiments as illustrated, for example, in connection with fluid bag 120 depicted in FIG. 3, bag width may be measured along a set of second straight lines (e.g., BW1 and BW2) extending across the first sheet 121 between the two opposing side portions 134 of the perimeter seal 130 in a direction transverse to the first straight line 140 (where the bag width is measured when no liquid is located in the fluid bag and the first sheet is lying on a flat horizontal surface). In one or more embodiments, the bag width BW may be described as decreasing when moving along at least a portion of the first straight line 140 from an upper location 148 on the first straight line 140 towards the bottom portion 136 of the perimeter seal 130.

In one or more embodiments, the upper location 148 may be described as located on the first straight line 140 at a position that is 20% or more, 30% or more, or 40% or more of the bag length BL from the intersection 142 of the first straight line 140 and the bottom portion 136 of the perimeter seal 130. In one or more embodiments, the upper location 148 may be described as located on the first straight line 140 at a position that is 70%) or less, 60% or less, or 50% or less of the bag length BL from the intersection 142 of the first straight line 140 and the bottom portion 136 of the perimeter seal 130. The upper and lower limits described above for the position of the upper location 148 on the first straight line 140 may be used in any combination, e.g., in one or more embodiments, the position of the upper location 148 may be 30% or more of the bag length BL above the intersection 142 and 50% or less of the bag length BL from the intersection 142.

Another illustrative embodiment of a fluid bag as described herein is depicted in FIG. 4. The depicted illustrative embodiment of fluid bag 220 is constructed of a first sheet 221, seen in FIG. 4, and a second sheet that is attached to the first sheet 221 about a perimeter seal 230 (where the second sheet is not visible in the view of FIG. 4 because it is behind the first sheet 221). The first sheet 221 and second sheet, along with the perimeter seal 230, define an interior volume of the fluid bag 220 between interior surfaces of the first and second sheets.

The perimeter seal 230 of this illustrative embodiment of fluid bag 220 also includes a top portion 232, two opposing side portions 234 and a bottom portion 236. The two opposing side portions 234 extend from the top portion 232 of the perimeter seal 230 to the bottom portion 236 of the perimeter seal 230 on opposite sides of the first sheet 221 of the fluid bag 220. In the illustrative embodiment of fluid bag 220 as depicted in FIG. 4, access to the interior volume of the fluid bag 220 may be had using port 226.

The illustrative embodiment of fluid bag 220 depicted in FIG. 4 also includes connection structure 224 located proximate the top portion 232 of the perimeter seal 230. The connection structure 224 is, in one or more embodiments, configured to suspend the fluid bag 220 below a connector (not shown) that is operably connected to a scale used in an extracorporeal blood treatment system as described herein. When suspended below a connector by the connection structure 224, the bottom portion 236 of the perimeter seal 230 is located below the top portion 232 of the perimeter seal 230 as the fluid bag 220 fills with liquid during a process being performed by an extracorporeal blood treatment system to which the fluid bag 220 is connected by one or more fluid lines. In the depicted illustrative embodiment, the connection structure 224 is in the form of three apertures that cooperate with structures on a connector as described herein to retain the fluid bag 220 on a scale of an extracorporeal blood treatment system, although, as described herein, the connection structure 224 may take a variety of different forms. As described herein, the shape of the first and second sheets and the associated perimeter seal connecting those sheets are selected to provide the reduced thickness as compared to a fluid bag of conventional shape and similar capacity as described herein. In the illustrative embodiment of fluid bag 220, the first sheet 221 is depicted and the shape of the fluid bag 220 will be described with reference to the first sheet 221 and the perimeter seal 230 extending around the perimeter of the first sheet 221. Further, the first sheet 221 is depicted in FIG. 4 as if it were lying on a flat horizontal surface with no liquid located in the fluid bag 220. It is in this condition that the shapes of one or more embodiments of the fluid bags described herein can be most accurately described.

With reference to FIG. 4, the illustrative embodiment of fluid bag 220 includes a bag length BL that can be measured along a first straight line 240 when no liquid is located in the fluid bag 220 and the first sheet 221 is lying on a flat horizontal surface. The first straight line 240 extends across the first sheet 221 between the top portion 232 and the bottom portion 236 of the perimeter seal 230. In the depicted embodiment, the first straight line 240 intersects with the inner edge of the top portion 232 of the perimeter seal 230 at intersection point 241 and the inner edge of the bottom portion 236 of the perimeter seal 230 at intersection point 242. In other words, the bag length BL can, in the depicted illustrative embodiment of fluid bag 220, be described as being the distance between intersection points 241 and 242 along first straight line 240.

In one or more embodiments, the first straight line 240 extends through a geometric center 231 of the two dimensional geometric figure defined by the perimeter seal 230 (again, when no liquid is located in the fluid bag 220 and the first sheet 221 is lying on a flat horizontal surface). In particular, the two dimensional geometric figure defined by the perimeter seal 230 is defined by an interior edge of the perimeter seal 230, i.e., the edge of the perimeter seal 230 that defines the interior volume of the fluid bag 220.

In one or more embodiments, the first straight line 240 is further positioned and oriented such that the bag length BL is a minimum bag length for the fluid bag 220 (while still extending through the geometric center of the two dimensional geometric figure defined by the perimeter seal 230). In other words, although the first straight line 240 is depicted as being generally vertical with respect to the top portion 232 and bottom portion 236 of the perimeter seal 230 although, as described herein, the first straight line 240 may be positioned in other orientations.

In one or more embodiments of fluid bags as described herein such as the illustrative embodiment of fluid bag 220, the fluid bag 120 may be described as having an upper bag area 252 and a lower bag area 254. The upper bag area 252 may be described as being found on the interior surface of the first sheet 221 and separated from the lower bag area 254 (which is also found on the interior surface of the first sheet 221) by a second straight line 244 that intersects the first straight line 240 at a midpoint 243 of the first straight line 240 (where the midpoint 243 of the first straight line 240 is measured between intersection points 241 and 242). The second straight line 244 extends between the opposing side portions 234 of the perimeter seal 230 between intersection points 245 and 246. In one or more embodiments, the second straight line may be oriented transverse to the first straight line 240.

As a result, the upper bag area 252 may be described as being defined by the second straight line 244, the top portion 232 of the perimeter seal 230 and the opposing side portions 234 of the perimeter seal 230 that extend from the second straight line 244 to the top portion 232 of the perimeter seal 230. In particular, the segments of the opposing side portions 234 of the perimeter seal 230 may extend towards the top portion 232 of the perimeter seal 230 from intersection points 245 and 246, where the intersection points 245 and 246 are the points at which the second straight line 244 intersects an interior edge of each of the opposing side portions 234 of the perimeter seal 230.

The lower bag area 254 is, as described herein, separated from the upper bag area 252 by the second straight line 244. The lower bag area 254 may further be described as being defined by the second straight line 244, the bottom portion 236 of the perimeter seal 230 and the opposing side portions 234 of the perimeter seal 230 that extend from the second straight line to the bottom portion 236 of the perimeter seal 230. In particular the segments of the opposing side portions 234 of the perimeter seal may extend towards the bottom portion 232 of the perimeter seal 230 from the intersection points 245 and 246 as described herein.

The illustrative embodiment of fluid bag 220 includes upper and lower bag areas

252 and 254 that, as compared to each other, fall within the ranges described herein, i.e., the lower bag area 254 may be 80% or less of the upper bag area 252. As a result, liquid collected within the fluid bag 220 may be forced towards the top portion 232 of the perimeter seal 230 such that the thickness of the fluid bag 220 within the lower bag area 252 is reduced as compared to a conventional fluid bag of the same capacity. In one or more alternative embodiments, the lower bag area 254 may be 70% or less of the upper bag area 252, 60% or less of the upper bag area 252, or even 50% or less of the upper bag area 252.

In one or more embodiments of fluid bags as described herein, bag width may be used to characterize the fluid bags. For example, the illustrative embodiment of fluid bag 220 may be characterized in terms of bag width, where the bag width is measured across the first sheet 221 of the fluid bag 220 between the two opposing side portions 234 of the perimeter seal 230 in a direction parallel to the second straight line 244. With reference to the illustrative embodiment of fluid bag 120 as depicted in FIG. 4, the bag width decreases when moving along the first straight line 240 towards the bottom portion 236 of the perimeter seal 230 in at least a portion of the lower bag area 254. This concept is illustrated in connection with the illustrative embodiment of fluid bag 220 with reference to the decreasing bag widths BW1 and BW2, where BW2 is closer to the bottom portion 236 of the perimeter seal 230 and shorter than BW1.

The fluid bags described herein may, in one or more embodiments, be characterized in terms of bag width relative to a selected location along the first straight line defining the bag length BL. In one or more embodiments as illustrated, for example, in connection with fluid bag 220 depicted in FIG. 4, bag width may be measured along a set of second straight lines (e.g., BW1 and BW2) extending across the first sheet 221 between the two opposing side portions 234 of the perimeter seal 230 in a direction transverse to the first straight line 240 (where the bag width is measured when no liquid is located in the fluid bag and the first sheet is lying on a flat horizontal surface). In one or more embodiments, the bag width BW may be described as decreasing when moving along at least a portion of the first straight line 240 from an upper location 248 on the first straight line 240 towards the bottom portion 236 of the perimeter seal 230. The upper location 248 may be located at a position as described above with respect to upper location 148 of fluid bag 120 in FIG. 3. Another illustrative embodiment of a fluid bag as described herein is depicted in FIG. 5. The depicted illustrative embodiment of fluid bag 320 is constructed of a first sheet 321, seen in FIG. 5, and a second sheet that is attached to the first sheet 321 about a perimeter seal 330 (where the second sheet is not visible in the view of FIG. 4 because it is behind the first 321). The first sheet 321 and second sheet, along with the perimeter seal 330, define an interior volume of the fluid bag 320 between interior surfaces of the first and second sheets.

The perimeter seal 330 of this illustrative embodiment of fluid bag 320 also includes a top portion 332, two opposing side portions 334 and a bottom portion 336. The two opposing side portions 334 extend from the top portion 332 of the perimeter seal 330 to the bottom portion 336 of the perimeter seal 330 on opposite sides of the first sheet 321 of the fluid bag 320. In the illustrative embodiment of fluid bag 320 as depicted in FIG. 5, access to the interior volume of the fluid bag 320 may be had using port 326.

The illustrative embodiment of fluid bag 320 depicted in FIG. 5 also includes connection structure 324 located proximate the top portion 332 of the perimeter seal 330. The connection structure 324 is, in one or more embodiments, configured to suspend the fluid bag 320 below a connector (not shown) that is operably connected to a scale used in an extracorporeal blood treatment system as described herein. In the depicted illustrative embodiment, the connection structure 324 is in the form of three apertures that cooperate with structures on a connector as described herein to retain the fluid bag 320 on a scale of an extracorporeal blood treatment system, although, as described herein, the connection structure 324 may take a variety of different forms.

As described herein, the shape of the first and second sheets and the associated perimeter seal connecting those sheets are selected to provide the reduced thickness as compared to a fluid bag of conventional shape and similar capacity as described herein. The illustrative embodiment of fluid bag 320 includes a bag length BL that can be measured along a first straight line 340 when no liquid is located in the fluid bag 320 and the first sheet 321 is lying on a flat horizontal surface. The first straight line 340 extends across the first sheet 321 between the top portion 332 and the bottom portion 336 of the perimeter seal 330. In the depicted embodiment, the first straight line 340 intersects with the inner edge of the top portion 332 of the perimeter seal 330 at intersection point 341 and the inner edge of the bottom portion 336 of the perimeter seal 330 at intersection point 342. In other words, the bag length BL can, in the depicted illustrative embodiment of fluid bag 320, be described as being the distance between intersection points 341 and 342 along first straight line 340.

In one or more embodiments, the first straight line 340 extends through a geometric center 331 of the two dimensional geometric figure defined by the perimeter seal 330 (again, when no liquid is located in the fluid bag 320 and the first sheet 321 is lying on a flat horizontal surface). In particular, the two dimensional geometric figure defined by the perimeter seal 330 is defined by an interior edge of the perimeter seal 330, i.e., the edge of the perimeter seal 330 that defines the interior volume of the fluid bag 320.

In one or more embodiments, the first straight line 340 is further positioned and oriented such that the bag length BL is a minimum bag length for the fluid bag 320 (while also extending through the geometric center 331 of the two dimensional geometric figure defined by the perimeter seal 330). In other words, although the first straight line 340 is depicted as being generally vertical with respect to the top portion 332 and bottom portion 336 of the perimeter seal 330 although, as described herein, the first straight line 340 may be positioned in other orientations.

In one or more embodiments of fluid bags as described herein such as the illustrative embodiment of fluid bag 320, the fluid bag 320 may be described as having an upper bag area 352 and a lower bag area 354. The upper bag area 352 and the lower bag area 354 may be determined as described above respect to the illustrative embodiments of fluid bags 120 and 220. In other words, the upper and lower bag areas 352 and 354 may be separated from each other by a second straight line 344 that intersects a midpoint 343 of the first straight line 340 and extends across the width of the bag 320 between intersection points 345 and 346 along the inner edges of the opposing side portions 334 of the perimeter seal 330. Furthermore, the relative size of the upper and lower bag areas 352 and 354 may be the same as those described above with respect to the illustrative embodiments of fluid bags 120 and 220.

As discussed above with respect to the illustrative embodiments of fluid bags 120 and 220, the width of fluid bag 320 as measured across the first sheet 321 between opposing side portions 334 of the perimeter seal 330 decreases when moving along the first straight line 340 towards the bottom portion 336 of the perimeter seal 330 in at least a portion of the lower bag area 354.

The fluid bags described herein may alternatively be characterized in terms of bag width relative to a selected location along the first straight line defining the bag length BL. In one or more embodiments as illustrated, for example, in connection with fluid bag 320 depicted in FIG. 5, bag width BW may be measured along a set of second straight lines extending across the first sheet 321 between the two opposing side portions 334 of the perimeter seal 330 in a direction transverse to the first straight line 340 (where the bag width is measured when no liquid is located in the fluid bag and the first sheet is lying on a flat horizontal surface). In one or more embodiments, the bag width BW may be described as decreasing when moving along at least a portion of the first straight line 340 from an upper location 343 on the first straight line 340 towards the bottom portion 336 of the perimeter seal 330.

The upper location 343 may be located at a position as described above with respect to upper locations 148 and 248 of fluid bags 120 and 220 in FIGS. 3 & 4 (noting that in the illustrative embodiment depicted in FIG. 5, the upper location corresponds to the intersection 343 of the first and second straight lines 340 and 344).

Further, in one or more embodiments of fluid bags described herein, such as illustrative embodiment of fluid bag 320, the bag width BW may be described as decreasing when moving along all of the first straight line 340 from an upper location 343 on the first straight line 340 to the intersection 342 of the first straight line 340 with the bottom portion 336 of the perimeter seal 330.

Another illustrative embodiment of a fluid bag as described herein is depicted in

FIG. 6. The depicted illustrative embodiment of fluid bag 420 is constructed of a first sheet 421, seen in FIG. 6, and a second sheet that is attached to the first sheet 421 about a perimeter seal 430 (where the second sheet is not visible in the view of FIG. 6 because it is behind the first sheet 421). The first sheet 421 and second sheet, along with the perimeter seal 430, define an interior volume of the fluid bag 420 between interior surfaces of the first and second sheets.

The perimeter seal 430 of this illustrative embodiment of fluid bag 420 also includes a top portion 432, two opposing side portions 434 and a bottom portion 436. The two opposing side portions 434 extend from the top portion 432 of the perimeter seal 430 to the bottom portion 436 of the perimeter seal 430 on opposite sides of the first sheet 421 of the fluid bag 420.

The illustrative embodiment of fluid bag 420 depicted in FIG. 6 also includes connection structure 424 located proximate the top portion 432 of the perimeter seal 430. The connection structure 424 is, in one or more embodiments, configured to suspend the fluid bag 420 below a connector (not shown) that is operably connected to a scale used in an extracorporeal blood treatment system as described herein. In the depicted illustrative embodiment, the connection structure 424 is in the form of three apertures that cooperate with structures on a connector as described herein to retain the fluid bag 420 on a scale of an extracorporeal blood treatment system, although, as described herein, the connection structure 424 may take a variety of different forms.

As described herein, the shape of the first and second sheets and the associated perimeter seal connecting those sheets are selected to provide the reduced thickness as compared to a fluid bag of conventional shape and similar capacity as described herein. The illustrative embodiment of fluid bag 420 includes a bag length BL that can be measured along a first straight line 440 when no liquid is located in the fluid bag 420 and the first sheet 421 is lying on a flat horizontal surface. The first straight line 440 extends across the first sheet 421 between the top portion 432 and the bottom portion 436 of the perimeter seal 430. In the depicted embodiment, the first straight line 440 intersects with the inner edge of the top portion 432 of the perimeter seal 430 at intersection point 441 and the inner edge of the bottom portion 436 of the perimeter seal 430 at intersection point 442. In other words, the bag length BL can, in the depicted illustrative embodiment of fluid bag 420, be described as being the distance between intersection points 441 and 442 along first straight line 440.

In one or more embodiments, the first straight line 440 extends through a geometric center 431 of the two dimensional geometric figure defined by the perimeter seal 430 (again, when no liquid is located in the fluid bag 420 and the first sheet 421 is lying on a flat horizontal surface). In particular, the two dimensional geometric figure defined by the perimeter seal 430 is defined by an interior edge of the perimeter seal 430, i.e., the edge of the perimeter seal 430 that defines the interior volume of the fluid bag 420. In one or more embodiments, the first straight line 440 is further positioned and oriented such that the bag length BL is a minimum bag length for the fluid bag 420 (while also extending through the geometric center 431 of the two dimensional geometric figure defined by the perimeter seal 430). In other words, although the first straight line 440 is depicted as being generally vertical with respect to the top portion 432 and bottom portion 436 of the perimeter seal 430 although, as described herein, the first straight line 440 may be positioned in other orientations.

In one or more embodiments of fluid bags as described herein such as the illustrative embodiment of fluid bag 420, the fluid bag 420 may be described as having an upper bag area 452 and a lower bag area 454 that are, as described above respect to the illustrative embodiments of fluid bags 120, 220, and 320, separated from each other by a second straight line 444 that intersects a midpoint 443 of the first straight line 440 and extends across the width of the bag 420 between intersection points 445 and 446 along the inner edges of the opposing side portions 434 of the perimeter seal 430. Furthermore, the relative size of the upper and lower bag areas 452 and 454 may be the same as those described above with respect to the illustrative embodiments of fluid bags 120, 220, and 320.

As discussed above with respect to the illustrative embodiments of fluid bags 120, 220, and 320, the width of fluid bag 420 as measured across the first sheet 421 between opposing side portions 434 of the perimeter seal 430 decreases in at least a portion of the lower bag area 454 of the fluid bag 420 when moving along the first straight line 440 from the midpoint 443 towards the bottom portion 436 of the perimeter seal 430. This concept is illustrated in connection with the illustrative embodiment of fluid bag 420 with reference to the decrease in bag width between bag widths BW1 and BW2.

In the depicted illustrative embodiment of fluid bag 420, however, the bag width in the lower bag area 454 increases after decreasing when continuing to move along the first straight line 440 towards the bottom portion 436 of the perimeter seal 430. This concept is illustrated in connection with the illustrative embodiment of fluid bag 420 with reference to the increase in bag width between bag widths BW2 and BW3 (where BW3 is closer to the bottom portion 436 of the perimeter seal 430 and longer than BW2) after the increasing bag width seen between bag widths BW1 and BW2. In one or more embodiments of fluid bags used in extracorporeal blood treatment systems as described herein in which bag width in a lower bag area decreases and then increases when moving towards the bottom portion of the perimeter seal, the bag shape in the lower bag area may be described as having an hourglass shape.

In fluid bags in which the bag width in the lower bag area decreases and then increases when moving towards the bottom portion of the perimeter seal such as in illustrative embodiment of fluid bag 420, the fluid bag 420 may be described as having, in one or more embodiments, an upper maximum bag width in the upper bag area 452 (where the width of the bag in the upper bag area 452 is measured transverse to the first straight line 440). The fluid bag 420 may also be described as having a minimum bag width in the lower bag area 454 at which the bag width is smallest when measured transverse to the first straight line 440 in the lower bag area 454 as described herein.

In one or more embodiments of such fluid bags, the minimum bag width in the lower bag area 454 may be less than the bag width at any location in the upper bag area 452. In one or more alternative embodiments, the minimum bag width in the lower bag area 454 may be less of the maximum bag width in the upper bag area 452. In one or more alternative embodiments, the minimum bag width in the lower bag area 454 may be 90% or less of the maximum bag width upper bag area 452, 80% or less of the maximum bag width in the upper bag area 452, 70% or less of the maximum bag width in the upper bag area 452, or 60% or less of the maximum bag width in the upper bag area 452. In one or more embodiments, the minimum bag width in the lower bag area 454 may be 20% or more of the upper maximum bag width in the upper bag area 452. In one or more alternative embodiments, the minimum bag width in the lower bag area 454 may be 30% or more of the upper maximum bag width in the upper bag area 452.

As described in connection with the illustrative embodiments of fluid bags 120,

220, and 320, the fluid bags described herein may, in one or more embodiments, be characterized in terms of bag width relative to a selected location along the first straight line defining the bag length BL. As depicted in connection with the illustrative

embodiment of fluid bag 420 depicted in FIG. 6, bag width may be measured along a set of second straight lines (e.g., BW1, BW2, and BW3) extending across the first sheet 421 between the two opposing side portions 434 of the perimeter seal 430 in a direction transverse to the first straight line 440. In one or more embodiments of fluid bags described herein, the bag width BW may be described as decreasing when moving along a portion of the first straight line 440 from an upper location 448 on the first straight line 440 towards the bottom portion 436 of the perimeter seal 430. The upper location 448 may be located at a position as described above with respect to, e.g., upper location 448 of fluid bag 420 in FIG. 3.

In addition, the illustrative embodiment of fluid bag 420 also demonstrates another optional feature that may be found in one or more embodiments of the fluid bags described herein, i.e., that the bag width increases when moving along a portion of the first straight line 440 from a lower location 449 on the first straight line 440 towards the bottom portion 436 of the perimeter seal 430 (see, e.g., bag widths BW2 and BW3). The lower location 449 is located between the upper location 448 and the bottom portion 436 of the perimeter seal 430 such that the bag width decreases (between locations 448 and 449) and then increases when moving along the first straight line 440 from the upper location 448 towards the bottom portion 436 of the perimeter seal 430.

In one or more embodiments of the fluid bags described herein, the fluid bags may have a minimum bag width below the upper location 448 at a position along the first straight line 440 that is 10% or more of the bag length BL above the intersection 442 of the first straight line 440 and the bottom portion 436 of the perimeter seal 430. In such an embodiment, the fluid bag 440 may have a maximum bag width above the upper location 448 (i.e., between the upper location and the intersection 441 between the first straight line 440 and the top portion 432 of the perimeter seal 430). In other words, the maximum bag width may be described as being located along an upper section of the first straight line 440, where the upper section extends from the upper location 448 to the top portion 432 of the perimeter seal 430 (i.e., the intersection between the first straight line 440 and the top portion 432 of the perimeter seal 430). In such an embodiment, the minimum bag width is located along a lower section of the first straight line 440, where the lower section extends from the upper location 448 to the intersection 442 of the first straight line 440 and the bottom portion 436 of the perimeter seal 430. The minimum bag width is less than the maximum bag width. In one or more embodiments of fluid bags having a maximum bag width in an upper section of the first straight line 440 and a minimum bag width in a lower section of the first straight line 440 as described herein, the minimum bag width may be 70% or less or 60% or less of the maximum bag width. In one or more embodiments of fluid bags having a maximum bag width in an upper section of the first straight line 440 and a minimum bag width in a lower section of the first straight line 440 as described herein, the minimum bag width may be 20% or more or 30% or more of the maximum bag width.

One illustrative embodiment of a system for connecting fluid bags as described herein to an extracorporeal blood treatment system is depicted in connection with FIGS. 7 and 8. The extracorporeal blood treatment system 510 includes a housing 512 and scales 518 which, as described herein, are configured to weigh a fluid bag 520 suspended from the scale 518 below the housing 512 and one or more pumps contained on or in the housing 512 such that the fluid bags 520 are suspended below such pumps (see, e.g., pumps 14 on housing 12 of extracorporeal blood treatment system 10 and fluid bags 120 in FIG. 2). Also as described herein, the fluid bags used in connection with such

extracorporeal blood treatment systems may include connection structure along the top portion of a perimeter seal of the fluid bag 520.

One illustrative embodiment of a connector 527 that may be used to connect a fluid bag 520 using connection structures on the fluid bag 520 to a scale 518 is depicted in FIG. 8. The connector 527 includes a handle 528 and a beam 529 with hooks 525 attached to the beam 529. The hooks 525 are, in one or more embodiments, configured to be inserted into, e.g., apertures, which may be used to form the connection structure on a fluid bag as described herein. While hooks 525 are configured to interface with the connection structure on the fluid bag 520, the handle 528 and beam 529 are configured to interface with the scale 518 such that the fluid bags 520 can be suspended below the housing 512 of the extracorporeal blood treatment system 510 (where the housing 512 is supported above a floor or other surface by a stand 511 as seen in, e.g., FIG. 7).

The illustrative embodiment of connector 527 and scales 518 are only one illustrative embodiment of structures that can be used to suspend the fluid bags as described herein below an extracorporeal blood treatment system and many other variations in connectors, connection structures and scales May be used to accomplish the function of suspending a fluid bag on an extracorporeal blood treatment system such that the contents within that fluid bag may be weighed if desired.

The complete disclosure of the patents, patent documents, and publications identified herein are incorporated by reference in their entirety as if each were individually incorporated. To the extent there is a conflict or discrepancy between this document and the disclosure in any such incorporated document, this document will control.

Illustrative embodiments of the fluid bags and systems using one or more of the fluid bags are discussed herein with some possible variations described. These and other variations and modifications in the invention will be apparent to those skilled in the art without departing from the scope of the invention, and it should be understood that this invention is not limited to the illustrative embodiments set forth herein. Accordingly, the invention is to be limited only by the claims provided below and equivalents thereof. It should also be understood that this invention also may be suitably practiced in the absence of any element not specifically disclosed as necessary herein.

Claims

CLAIMS: What is claimed is:

1. A fluid bag configured to contain liquid therein, the bag comprising:

a first sheet and a second sheet;

a perimeter seal that defines an interior volume of the fluid bag between interior surfaces of the first and second sheets, wherein the first sheet is attached to the second sheet along the perimeter seal, and wherein the perimeter seal comprises a top portion, a bottom portion located opposite from the top portion, and two opposing side portions extending from the top portion of the perimeter seal to the bottom portion of the perimeter seal;

connection structure located proximate the top portion of the perimeter seal, wherein the connection structure is configured to suspend the fluid bag below a connector such that the bottom portion of the perimeter seal is located below the top portion as the fluid bag fills with liquid when suspended from the connection structure; a bag length measured along a first straight line extending across the first sheet between the bottom portion and the top portion of the perimeter seal, wherein the bag length is measured when no liquid is located in the fluid bag and the first sheet is lying on a flat horizontal surface, and wherein the first straight line extends through a geometric center of a two-dimensional geometric figure defined by the perimeter seal when no liquid is located in the fluid bag and the first sheet is lying on a flat horizontal surface;

an upper bag area on the interior surface of the first sheet, wherein the upper bag area is defined by a second straight line intersecting the first straight line at a midpoint of the first straight line, the top portion of the perimeter seal, and the opposing side portions of the perimeter extending from the second straight line to the top portion of the perimeter seal, and wherein the second straight line extends between the opposing side portions of the perimeter seal and is oriented transverse to the first straight line; and a lower bag area on the interior surface of the first sheet, wherein the lower bag area is defined by the second straight line, the bottom portion of the perimeter seal, and the opposing side portions of the perimeter extending from the second straight line to the bottom portion of the perimeter seal;

wherein the lower bag area is 80% or less of the upper bag area when no liquid is located in the fluid bag and the first sheet is lying on a flat horizontal surface.

2. A fluid bag according to claim 1, wherein the lower bag area is 70% or less of the upper bag area.

3. A fluid bag according to claim 1, wherein the lower bag area is 60% or less of the upper bag area.

4. A fluid bag according to claim 1, wherein the lower bag area is 50% or less of the upper bag area.

5. A fluid bag according to any one of claims 1 to 4, wherein the fluid bag comprises a bag width measured across the first sheet between the two opposing side portions of the perimeter seal in a direction parallel to the second straight line, wherein the bag width is measured when no liquid is located in the fluid bag and the first sheet is lying on a flat horizontal surface, and wherein the bag width decreases when moving along the first straight line towards the bottom portion of the perimeter seal in at least a portion of the lower bag area.

6. A fluid bag according to any one of claims 1 to 4, wherein the fluid bag comprises a bag width measured across the first sheet between the two opposing side portions of the perimeter seal in a direction parallel to the second straight line, wherein the bag width is measured when no liquid is located in the fluid bag and the first sheet is lying on a flat horizontal surface, and wherein the bag width in at least a portion of the lower bag area decreases when moving along the first straight line towards the bottom portion of the perimeter seal; and further wherein the bag width in the lower bag area increases after decreasing when continuing to move along the first straight line towards the bottom portion of the perimeter seal.

7. A fluid bag according to claim 6, wherein the fluid bag comprises a minimum bag width in the lower bag area, and further wherein the minimum bag width is less than the bag width at any location in the upper bag area.

8. A fluid bag according to claim 6, wherein the fluid bag comprises an upper maximum bag width in the upper bag area and a minimum bag width in the lower bag area, and further wherein the minimum bag width is 90% or less of the maximum bag width.

9. A fluid bag configured to contain liquid therein, the bag comprising:

a first sheet and a second sheet;

a bag width measured along a set of second straight lines extending across the first sheet between the two opposing side portions of the perimeter seal in a direction transverse to the first straight line, wherein the bag width is measured when no liquid is located in the fluid bag and the first sheet is lying on a flat horizontal surface;

wherein the bag width decreases when moving along at least a portion of the first straight line from an upper location on the first straight line towards the bottom portion of the perimeter seal, wherein the upper location is located on the first straight line at a position that is 20% or more of the bag length from an intersection of the first straight line and the bottom portion of the perimeter seal.

10. A fluid bag according to claim 9, wherein the position of the upper location is 30%> or more of the bag length from the intersection of the first straight line and the bottom portion of the perimeter seal.

11. A fluid bag according to claim 9, wherein the position of the upper location is 40% or more of the bag length from the intersection of the first straight line and the bottom portion of the perimeter seal.

12. A fluid bag according to any one of claims 9 to 11, wherein the position of the upper location is 70% or less of the bag length from the intersection of the first straight line and the bottom portion of the perimeter seal.

13. A fluid bag according to any one of claims 9 to 11, wherein the position of the upper location is 60% or less of the bag length from the intersection of the first straight line and the bottom portion of the perimeter seal.

14. A fluid bag according to any one of claims 9 to 11, wherein the position of the upper location is 50% or less of the bag length from the intersection of the first straight line and the bottom portion of the perimeter seal.

15. A fluid bag according to claim 9, wherein the bag width increases when moving along a portion of the first straight line from a lower location on the first straight line towards the bottom portion of the perimeter seal, wherein the lower location is located between the upper location and the bottom portion of the perimeter seal such that the bag width decreases and then increases when moving along the first straight line from the upper location towards the bottom portion of the perimeter seal.

16. A fluid bag according to claim 15, wherein the fluid bag comprises a minimum bag width below the upper location at a position along the first straight line that is 10% or more of the bag length above the intersection of the first straight line and the bottom portion of the perimeter seal, wherein the fluid bag comprises a maximum bag width above the upper location, wherein the maximum bag width is greater than the minimum bag width and is located along an upper section of the first straight line extending from the upper location to the top portion of the perimeter seal, and wherein the minimum bag width is located along a lower section of the first straight line extending from the upper location to the intersection of the first straight line and the bottom portion of the perimeter seal.

17. A fluid bag according to claim 16, wherein the minimum bag width is 70% or less of the maximum bag width.

18. A fluid bag according to claim 16, wherein the minimum bag width is 60% or less of the maximum bag width.

19. A fluid bag according to any one of claims 16 to 18, wherein the minimum bag width is 20% or more of the maximum bag width.

20. A fluid bag according to any one of claims 16 to 18, wherein the minimum bag width is 30% or more of the maximum bag width.

21. A treatment system comprising:

a pump configured to move fluid through the treatment system; and

a connector configured to suspend a fluid bag according to any one of claims 1 to 20 below the pump.

22. A treatment system according to claim 21, wherein the system further comprises: an apparatus configured to perform hemodialysis, hemodiafiltration, hemofiltration, or peritoneal dialysis;

wherein the fluid bag suspended below the pump is in fluid communication with the apparatus such that fluid leaving the apparatus is collected in the fluid bag.

23. A treatment system according to any one of claims 21 to 22, wherein the system comprises a plurality of connectors configured to suspend a plurality of the fluid bags according to any one of claims 1 to 20 below the pump, wherein each connector of the plurality of connectors is configured to suspend one fluid bag of the plurality of fluid bags.

24. A treatment system according to claim 23, wherein two or more fluid bags of the plurality of fluid bags are suspended below the pump such that the first and second sheets of the two or more fluid bags are aligned with each other.