U.S. patent application number 09/878443 was filed with the patent office on 2001-10-04 for flow-through peritoneal dialysis systems and methods with on-line dialysis solution regeneration.
Invention is credited to Brugger, James M., Burbank, Jeffrey H., Treu, Dennis M..
Application Number | 20010027289 09/878443 |
Document ID | / |
Family ID | 22398477 |
Filed Date | 2001-10-04 |
United States Patent
Application |
20010027289 |
Kind Code |
A1 |
Treu, Dennis M. ; et
al. |
October 4, 2001 |
Flow-through peritoneal dialysis systems and methods with on-line
dialysis solution regeneration
Abstract
Peritoneal dialysis is performed by circulating peritoneal
dialysis solution through a peritoneal cavity by conveying
peritoneal dialysis solution through an inlet branch into the
peritoneal cavity and by withdrawing peritoneal dialysis solution
through an outlet branch from the peritoneal cavity. Peritoneal
dialysis solution in the outlet branch is conveyed along a first
side of a porous membrane while conveying a regeneration solution
containing at least one regenerating agent along a second side of
the porous membrane. The membrane is configured to transport the
regenerating agent into the peritoneal dialysis solution while
transporting waste from the peritoneal dialysis solution into the
regeneration solution, thereby creating a regenerated peritoneal
dialysis solution. The regenerated peritoneal dialysis solution is
circulated through the inlet branch into the peritoneal cavity.
Inventors: |
Treu, Dennis M.; (Bedford,
NH) ; Burbank, Jeffrey H.; (Boxford, MA) ;
Brugger, James M.; (Newburyport, MA) |
Correspondence
Address: |
Ryan Kromholz & Manion, S.C.
PO Box 26618
Milwaukee
WI
53226
US
|
Family ID: |
22398477 |
Appl. No.: |
09/878443 |
Filed: |
June 12, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09878443 |
Jun 12, 2001 |
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09512132 |
Feb 23, 2000 |
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6254567 |
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60121733 |
Feb 26, 1999 |
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Current U.S.
Class: |
604/29 |
Current CPC
Class: |
A61M 1/288 20140204;
A61M 1/284 20140204; A61M 1/28 20130101; A61M 1/1696 20130101 |
Class at
Publication: |
604/29 |
International
Class: |
A61M 001/00 |
Claims
We claim:
1. A system for conducting peritoneal dialysis comprising a pumping
assembly to circulate peritoneal dialysis solution through a
peritoneal cavity to perform peritoneal dialysis including a inlet
branch to convey peritoneal dialysis solution into the peritoneal
cavity and an outlet branch to withdraw peritoneal dialysis
solution from the peritoneal cavity, and a regeneration assembly
coupled in-line between the inlet and outlet branches, the
regeneration assembly including a source of a regeneration solution
that carries at least one agent for regenerating spent peritoneal
dialysis solution, and a porous membrane having a first side, along
which peritoneal dialysis solution is circulated by the pumping
assembly from the outlet branch to the inlet branch, and a second
side, along which the regeneration solution is circulated, the
porous membrane being configured to transport waste from spent
peritoneal dialysis solution into the regeneration solution and to
transport the regenerating agent from the regeneration solution
into spent peritoneal dialysis solution, the regeneration assembly
operating to create from peritoneal dialysis solution in the outlet
branch, a regenerated dialysis solution for conveyance through the
inlet branch into the peritoneal cavity.
2. A system according to claim 1 wherein the regeneration assembly
includes a pump to convey regeneration solution from the source
along the second side of the porous membrane.
3. A system according to claim 1 wherein the regeneration assembly
includes a waste line to remove regeneration solution from the
second side of the porous membrane.
4. A system according to claim 3 wherein the waste line
communicates with a drain.
5. A system according to claim 3 wherein the waste line
communicates with a waste-receiving container.
6. A system according to claim 3 wherein the waste line
communicates with the source of regeneration solution to
recirculate at least a portion of the regeneration solution.
7. A system according to claim 1 wherein the regenerating agent
includes an electrolyte.
8. A system according to claim 1 wherein the regenerating agent
includes a buffering agent.
9. A system according to claim 8 wherein the buffering agent
comprises a bicarbonate buffering material.
10. A system according to claim 8 wherein the buffering agent
comprises a lactate buffering agent.
11. A system according to claim 1 wherein the regenerating agent
includes an electrolyte and a buffering agent.
12. A system according to claim 11 wherein the buffering agent
comprises a bicarbonate buffering material.
13. A system according to claim 11 wherein the buffering agent
comprises a lactate buffering agent.
14. A system according to claim 1 wherein the source of
regeneration solution draws water from a source of water.
15. A system according to claim 14 wherein the source of water
comprises tap water.
16. A system according to claim 14 wherein the source of
regeneration solution includes a device to treat water drawn from
the source of water.
17. A system according to claim 14 wherein the source of
regeneration solution includes a device to mix the at least one
regenerating agent with water drawn from the source of water.
18. A system according to claim 1 wherein the source of
regeneration solution draws water from a source of running
water.
19. A system according to claim 18 wherein the source of running
water is tap water.
20. A system according to claim 18 wherein the source of
regeneration solution includes a device to treat water drawn from
the source of the running water.
21. A system according to claim 18 wherein the source of
regeneration solution includes a device to mix the at least one
regenerating agent with water drawn from the source of running
water.
22. A system according to claim 1 wherein the source of
regeneration solution includes a container holding a volume of
water in which the at least one regenerating agent is mixed.
23. A system according to claim 1 wherein the source of
regeneration solution includes a first container holding a volume
of water and a second container that holds the at least one
regenerating agent, the second container being located within the
first container and including a wall material that, when contacted
by water, transports the at least one regenerating agent into the
water, thereby forming the regeneration solution.
24. A system according to claim 1 wherein the regeneration assembly
includes a device to heat the regeneration solution before
circulation along the second side of the porous membrane.
25. A system according to claim 1 wherein the regeneration assembly
includes a sterilizing filter between the source of regeneration
solution and the porous membrane.
26. A system according to claim 1 wherein the porous membrane
comprises a semipermeable membrane.
27. A system according to claim 26 wherein the porous membrane
comprises a bundle of hollow fibers each having an exterior, which
comprises the second side of the porous membrane, and an interior
lumen, which comprises the first side of the porous membrane.
28. A system according to claim 1 wherein the porous membrane
transports waste and the at least one regenerating agent by
diffusion, convection, or both.
29. A system according to claim 1 wherein the inlet branch
communicates with a first access device providing access to the
peritoneal cavity, and wherein the outlet branch communicates a
second access device providing access to the peritoneal cavity
independent of the access provided by the first device.
30. A system according to claim 29 wherein the pumping assembly
includes a controller that withdraws peritoneal dialysis solution
through the second access device into the regeneration assembly
while conveying regenerated peritoneal dialysis solution from the
regeneration device into the peritoneal cavity through the first
access device.
31. A system according to claim 29 wherein at least one of the
first and second access devices comprises a subcutaneous access
port.
32. A system according to claim 1 wherein the inlet and outlet
branches jointly communicate with a single access device that
provides common access to the peritoneal cavity.
33. A system according to claim 32 wherein the pumping assembly
includes a controller operating in a draw mode, to withdraw
peritoneal dialysis solution from the peritoneal cavity through the
single access device into the regeneration assembly, and a return
mode, to convey regenerated peritoneal dialysis solution into the
peritoneal cavity through the single access device.
34. A system according to claim 33 wherein the controller toggles
between the draw mode and the return mode.
35. A system according to claim 33 wherein the regeneration
assembly includes a reservoir in the inlet branch to collect
regenerated peritoneal dialysis solution during the draw mode.
36. A system according to claim 35 wherein the regeneration
assembly includes a sensor to sense presence of regenerated
dialysis solution in the reservoir and to generate an output
relating to volume of regenerated peritoneal dialysis solution
present in the reservoir, and wherein the controller toggles
between the draw mode and return mode in response to the
output.
37. A system according to claim 32 wherein the single access device
comprises a subcutaneous access port.
38. A system according to claim 1 wherein the regeneration assembly
includes a fluid balancing module to maintain a volumetric balance
between waste and regenerating agent transported by the porous
membrane.
39. A system according to claim 1 wherein the regeneration assembly
includes an ultrafiltration module to selectively transport a
preselected greater volume of waste than regenerating agent.
40. A system according to claim 1 wherein the pumping assembly
accommodates circulation of a cleaning or disinfecting agent
through the inlet and outlet branches, bypassing the peritoneal
cavity.
41. A system according to claim 1 wherein the regeneration assembly
accommodates circulation of a cleaning or disinfecting agent along
the first and second sides of the porous membrane.
42. A method for conducting peritoneal dialysis comprising steps of
(i) circulating peritoneal dialysis solution through a peritoneal
cavity to perform peritoneal dialysis by conveying peritoneal
dialysis solution through an inlet branch into the peritoneal
cavity and by withdrawing peritoneal dialysis solution through an
outlet branch from the peritoneal cavity, (ii) during at least a
portion of step (i), conveying peritoneal dialysis solution in the
outlet branch along a first side of a porous membrane while
conveying a regeneration solution containing at least one
regenerating agent along a second side of the porous membrane, the
membrane being configured to transport the regenerating agent into
the peritoneal dialysis solution while transporting waste from the
peritoneal dialysis solution into the regeneration solution,
thereby creating a regenerated peritoneal dialysis solution, and
(iii) during at least a portion of step (i), circulating the
regenerated peritoneal dialysis solution through the inlet branch
into the peritoneal cavity.
43. A method according to claim 42 wherein steps (ii), and (iii)
are performed simultaneously.
44. A method according to claim 42 wherein steps (ii) and (iii) are
performed sequentially.
45. A method according to claim 42 wherein, during step (ii), a
prescribed volumetric balance is maintained between waste and
regenerating agent transported by the porous membrane to achieve
fluid balancing.
46. A method according to claim 42 wherein, during step (ii), a
preselected greater volume of waste than regenerating agent is
selectively transported by the porous membrane to achieve
ultrafiltration.
47. A method according to claim 42 wherein, during step (ii),
regeneration solution is removed from the second side of the porous
membrane to a waste line.
48. A method according to claim 42 wherein, during step (ii), water
is drawn from a source of water to create the regeneration
solution.
49. A method according to claim 48 wherein the source of water is
tap water.
50. A method according to claim 48 wherein, during step (ii), water
that is drawn from the source of water is treated.
51. A method according to claim 48 wherein, during step (ii), the
at least one regenerating agent is mixed with water drawn from the
source of water.
52. A method according to claim 48 wherein, during step (ii), water
is drawn from a source of running water to create the regeneration
solution.
53. A method according to claim 52 wherein the source of running
water is tap water.
54. A method according to claim 52 wherein, during step (ii), water
that is drawn from the source of running water is treated.
55. A method according to claim 52 wherein, during step (ii), the
at least one regenerating agent is mixed with water drawn from the
source of running water.
56. A method according to claim 42 wherein, during step (ii), the
regeneration solution is heated before circulation along the second
side of the porous membrane.
57. A method according to claim 42 wherein, during step (ii), the
regeneration solution is passed through a sterilizing filter before
circulation along the second side of the porous membrane.
58. A method according to claim 42 wherein, after completion of
step (i), a cleaning or disinfecting agent is circulated through
the inlet and outlet branches, bypassing the peritoneal cavity.
59. A method according to claim 42 wherein, after completion of
step (i), a cleaning or disinfecting agent is circulated along the
first and second sides of the porous membrane.
Description
RELATED APPLICATION
[0001] This application is a continuation-in-part of copending
United States Provisional Patent Application Ser. No. 60/121,733,
filed Feb. 26, 1999, and entitled "Flow-Through Peritoneal Dialysis
Systems and Methods with On-Line Dialysis Solution Regeneration,"
which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The invention relates to systems and methods for performing
peritoneal dialysis.
BACKGROUND OF THE INVENTION
[0003] Peritoneal Dialysis (PD) periodically infuses sterile
aqueous solution into the peritoneal cavity. This solution is
called peritoneal dialysis solution, or dialysate. Diffusion and
osmosis exchanges take place between the solution and the
bloodstream across the natural body membranes. These exchanges
remove the waste products that the kidneys normally excrete. The
waste products typically consist of solutes like sodium and
chloride ions, and the other compounds normally excreted through
the kidneys like urea, creatinine, and water. The diffusion of
water across the peritoneal membrane during dialysis is called
ultrafiltration.
[0004] Conventional peritoneal dialysis solutions include dextrose
in concentrations sufficient to generate the necessary osmotic
pressure to remove water from the patient through
ultrafiltration.
[0005] Continuous Ambulatory Peritoneal Dialysis (CAPD) is a
popular form of PD. A patient performs CAPD manually about four
times a day. During CAPD, the patient drains spent peritoneal
dialysis solution from his/her peritoneal cavity. The patient then
infuses fresh peritoneal dialysis solution into his/her peritoneal
cavity. This drain and fill procedure usually takes about 1
hour.
[0006] Automated Peritoneal Dialysis (APD) is another popular form
of PD. APD uses a machine, called a cycler, to automatically
infuse, dwell, and drain peritoneal dialysis solution to and from
the patient's peritoneal cavity. APD is particularly attractive to
a PD patient, because it can be performed at night while the
patient is asleep. This frees the patient from the day-to-day
demands of CAPD during his/her waking and working hours.
[0007] APD offers flexibility and quality of life enhancements to a
person requiring dialysis. APD can free the patient from the
fatigue and inconvenience that the day to day practice of CAPD
represents to some individuals. APD can give back to the patient
his or her waking and working hours free of the need to conduct
dialysis exchanges.
[0008] Still, CAPD and APD as practiced today require the use of
bagged solutions, which are expensive and difficult to handle and
connect. Bagged solutions also do not permit the use of bicarbonate
buffering solutions due to sterilization issues. The complexity and
size of past machines and associated disposables for various APD
modalities have dampened widespread patient acceptance of APD as an
alternative to manual peritoneal dialysis methods.
SUMMARY OF THE INVENTION
[0009] The invention provides systems and methods for conducting
peritoneal dialysis.
[0010] One aspect of the invention provides a system for conducting
peritoneal dialysis. The system comprises a pumping assembly to
circulate peritoneal dialysis solution through a peritoneal cavity
to perform peritoneal dialysis. The pumping assembly includes an
inlet branch to convey peritoneal dialysis solution into the
peritoneal cavity and an outlet branch to withdraw peritoneal
dialysis solution from the peritoneal cavity. The system also
includes a regeneration assembly coupled in-line between the inlet
and outlet branches. The regeneration assembly includes a source of
a regeneration solution that carries at least one agent for
regenerating spent peritoneal dialysis solution. The regenerating
agent can include, e.g., an electrolyte and a buffering agent. The
regeneration assembly also includes a porous membrane having a
first side and a second side. The pumping assembly circulates
peritoneal dialysis solution along the first side of the porous
membrane from the outlet branch to the inlet branch. The
regeneration solution is circulated along the second side of the
porous membrane. The porous membrane is configured to transport
waste from spent peritoneal dialysis solution into the regeneration
solution and to transport the regenerating agent from the
regeneration solution into spent peritoneal dialysis solution. The
transport can occur, e.g., by diffusion, convection, or both. The
regeneration assembly thereby operates to create from peritoneal
dialysis solution in the outlet branch, a regenerated dialysis
solution for conveyance through the inlet branch into the
peritoneal cavity.
[0011] The source of regeneration solution can draw water from a
source of water, which can comprise, e.g., running tap water. In
one embodiment, the source of regeneration solution includes a
device to treat water drawn from the source of water, as well as a
device to mix the at least one regenerating agent with water drawn
from the source of water.
[0012] The source of regeneration solution can alternatively
include a container holding a volume of water in which the at least
one regenerating agent is mixed. In one embodiment, the source of
regeneration solution includes a first container holding a volume
of water and a second container that holds the at least one
regenerating agent. The second container is located within the
first container. The second container includes a wall material
that, when contacted by water, transports the at least one
regenerating agent into the water, thereby forming the regeneration
solution.
[0013] In one embodiment, the regeneration assembly includes a
device to heat the regeneration solution before circulation along
the second side of the porous membrane.
[0014] In one embodiment, the inlet branch communicates with a
first access device providing access to the peritoneal cavity, and
the outlet branch communicates a second access device providing
access to the peritoneal cavity independent of the access provided
by the first device. In this arrangement, the pumping assembly can
include a controller that withdraws peritoneal dialysis solution
through the second access device into the regeneration assembly
while conveying regenerated peritoneal dialysis solution from the
regeneration device into the peritoneal cavity through the first
access device. At least one of the first and second access devices
can comprise, e.g., a subcutaneous access port.
[0015] In one embodiment, the inlet and outlet branches jointly
communicate with a single access device that provides common access
to the peritoneal cavity. In this arrangement, the pumping assembly
can include a controller operating in a draw mode, to withdraw
peritoneal dialysis solution from the peritoneal cavity through the
single access device into the regeneration assembly, and a return
mode, to convey regenerated peritoneal dialysis solution into the
peritoneal cavity through the single access device. The single
access device comprises, e.g., a subcutaneous access port.
[0016] In one embodiment, the regeneration assembly includes a
fluid balancing module to maintain a volumetric balance between
waste and regenerating agent transported by the porous
membrane.
[0017] In one embodiment, the regeneration assembly includes an
ultrafiltration module to selectively transport a preselected
greater volume of waste than regenerating agent.
[0018] In one embodiment, the pumping assembly can accommodate
circulation of a cleaning or disinfecting agent through the inlet
and outlet branches, bypassing the peritoneal cavity. The
regeneration assembly can also accommodate circulation of a
cleaning or disinfecting agent along the first and second sides of
the porous membrane.
[0019] Another aspect of the invention provides a method for
conducting peritoneal dialysis. The method (i) circulates
peritoneal dialysis solution through a peritoneal cavity to perform
peritoneal dialysis by conveying peritoneal dialysis solution
through an inlet branch into the peritoneal cavity and by
withdrawing peritoneal dialysis solution through an outlet branch
from the peritoneal cavity. During at least a portion of step (i),
the method (ii) conveys peritoneal dialysis solution in the outlet
branch along a first side of a porous membrane while conveying a
regeneration solution containing at least one regenerating agent
along a second side of the porous membrane. The membrane is
configured to transport the regenerating agent into the peritoneal
dialysis solution while transporting waste from the peritoneal
dialysis solution into the regeneration solution, thereby creating
a regenerated peritoneal dialysis solution. During at least a
portion of step (i), the method (iii) circulates the regenerated
peritoneal dialysis solution through the inlet branch into the
peritoneal cavity.
[0020] The steps (ii), and (iii) can be performed simultaneously or
sequentially.
[0021] During step (ii), a prescribed volumetric balance can be
maintained between waste and regenerating agent transported by the
porous membrane to achieve fluid balancing. Also during step (ii),
a preselected greater volume of waste than regenerating agent cen
be selectively transported by the porous membrane to achieve
ultrafiltration. $$
[0022] Other features and advantages of the inventions are set
forth in the following specification and attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is a schematic view of a system for conducting
flow-through peritoneal dialysis, showing a dual access with the
peritoneal cavity;
[0024] FIG. 2 is a schematic view of a system for conducting
flow-through peritoneal dialysis, showing a single access with the
peritoneal cavity;
[0025] FIG. 3 is a side section view of a subcutaneous peritoneal
cavity access device, showing the associated valve assembly in a
closed condition;
[0026] FIG. 4 is a side section view of the subcutaneous peritoneal
cavity access device shown in FIG. 3, showing the associated valve
assembly in a closed condition;
[0027] FIG. 5 is a schematic view of a system like that shown in
FIG. 1, in which the regeneration solution is supplied in a batch
process;
[0028] FIG. 6 is a schematic view of a system like that shown in
FIG. 1, in which the regeneration solution is supplied in a
continuous process; and
[0029] FIG. 7 is a schematic view of the regeneration solution
module like that shown in FIG. 1, which also includes fluid
balancing and fluid removal capabilities.
[0030] 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 EMBODIMENTS
[0031] I. System Overview
[0032] FIG. 1 shows a system 10 for conducting flow-through
peritoneal dialysis, which embodies the features of the invention.
The system 10 includes a peritoneal dialysis solution flow set 12
that is connected to an access device 18. The access device 18
establishes communication between the system 10 and the peritoneal
cavity 20 of a patient.
[0033] The system 10 also includes a cycler 14. The cycler 14
interacts with the flow set 12, to pump peritoneal dialysis
solution into and out of the patient's peritoneal cavity 20.
[0034] The system 10 also includes a controller 16. The controller
16 governs the interaction between the set 12 and the cycler 14, to
perform a selected flow-through peritoneal dialysis procedure.
[0035] The flow set 12 includes an in-line membrane device 22. The
membrane device 22 includes a housing 24, which encloses a
semipermeable membrane 26. The membrane 26 can have different
geometries. In the illustrated embodiment, the membrane 26
comprises a bundle of hollow fibers, through which peritoneal
dialysis fluid drawn from the peritoneal cavity 20 of the patient
flows.
[0036] The membrane 26 compartmentalizes the chamber 24 into a
patient side 28 and a regeneration side 30. In the illustrated
embodiment, the patient side 28 comprises the bores of the bundled
hollow fibers, and the regeneration side 30 comprises the interior
space surrounding the bundled hollow fibers. An inlet port 32 and
an outlet port 34 convey dialysis solution into and out of the
patient side 28 of the chamber 24 (i.e., into and out of the bores
of the hollow fibers). An inlet port 36 and outlet port 38 convey
regeneration solution into and out of the regeneration side 30 of
chamber 24.
[0037] The set 12 circulates peritoneal dialysis solution,
transported from the patient's peritoneal cavity 20, along the
patient side 28 of the membrane 26. The set 12 also circulates a
regeneration solution containing electrolytes and/or bicarbonate
buffering materials along the regeneration side 30 of the membrane
26. The cycler 14 creates and supplies the regeneration solution,
as will be described in detail later.
[0038] The pores of the membrane 26 are sized to pass, by diffusion
and convection, waste and uremic toxins from the patient side 28 to
the regeneration side 30. The pores of the membrane 26 are also
sized to pass, by the same transport mechanisms, electrolytes and
bicarbonate buffering materials from the regeneration side 30 to
the patient side 28.
[0039] The in-line membrane device 22 thereby makes possible the
continuous, on-line regeneration of peritoneal dialysis solution
circulated in the set 12.
[0040] The cycler 14 includes a fluid source 40. In the embodiment
shown in FIG. 1, the fluid source 40 comprises a water treatment
module 42, a regeneration solution module 44, and a waste module
46.
[0041] The water treatment module 42 receives water from a
household water supply and processes the water, using e.,g.,
filtration, or absorption, or filtration and absorption, or reverse
osmosis (with or without pre-filtration and/or absorption), or
de-ionization (with or without pre-filtration and/or absorption),
or reverse osmosis and de-ionization (with or without
pre-filtration and/or absorption). By such processing, the water
treatment module 42 creates water substantially free of pyrogens
and microorganisms.
[0042] The regeneration solution module 44 receives processed water
from the water treatment module 42. The regeneration solution
module 44 mixes electrolytes and/or buffering agents with the
processed water to create the regeneration solution. The module 44
verifies the make up of the solution and heats the solution to body
temperature, for delivery to the regeneration side 30 of the
membrane device 22.
[0043] The waste module 46 directs system drain and waste water
from the regeneration side 30 of the membrane device 22 to a drain
56 or other selected receptacle.
[0044] The fluid source 40 of the cycler 14 obviates the need for
bagged solutions, except for initially priming the set 12 prior to
conducting a flow-through peritoneal dialysis procedure. The fluid
source 40 makes possible the continuous, on-line regeneration of
peritoneal dialysis solution, which the set 12 circulates from and
into the patient's peritoneal cavity 20.
[0045] The processing controller 16 can comprise a stand-alone
micro-processor controlled module or a mechanically and /or
electrically controlled module linked to the cycler 14. In the
illustrated embodiment, however, the cycler 14 and controller 16
are located within a common housing 48. The housing 48 presents a
compact footprint, suited for operation upon a table top or other
relatively small surface normally found in the home.
[0046] In the illustrated embodiment, the controller 16 also
includes an interactive user interface 50. The interface 50
comprises some form of a display 52, which can be analog or
digital, and some form of a patient input device 54, such as knobs,
dials, switches, keyboard or a touch screen on the display 52. The
interface 50 can e.g., present on the display 52 the current status
of the cycler 14, or prompt the user to input commands and
information, or receive data from the various sensors and other
components of the cycler 14, record the data in memory, or control
the operation of the active components of the cycler 14 (such as
valves, pumps, heaters, etc.), or alert the patient to abnormal or
failure conditions in the cycler 14 with alarms or other
indicators, or any or all of these functions. Additionally, the
interface 50 can be linked, e.g., by modem, to a central monitoring
station or a central data collection site.
[0047] The set 12 can be a single use, disposable item, or it can,
with cleaning and disinfection, be reusable. This aspect with be
described in greater detail later.
[0048] In use, the cycler 14 draws peritoneal dialysis solution
from the patient's peritoneal cavity 20, regenerates the dialysis
solution, and returns the regenerated dialysis solution to the
patient's peritoneal cavity 20, in a continuous or semi-continuous,
extracoporeal path. The constant or semi-constant flow of
peritoneal dialysis solution through the peritoneal cavity 20
provides sustained, high clearance of waste and toxins, which are
conveyed to the drain 56. The on-line regeneration of dialysis
solution provides lower costs and requires less manipulation and
set up than systems relying upon the connection and disconnection
of bagged solutions.
[0049] II. Flow-Through Peritoneal Dialysis Modalities
[0050] The system 10 is particularly well suited to perform
flow-through peritoneal dialysis (FTPD). For this reason, the use
of the system 10 to perform various modalities of FTPD will be
described in detail.
[0051] (A) Dual Access to the Peritoneal Cavity
[0052] In the embodiment shown in FIG. 1, the access device 18
provides dual access, having a dedicated inlet 58 for conveying
solution into the peritoneal cavity 20 and a dedicated outlet 60
for conveying solution from the peritoneal cavity 20. Dual access
provides continuous flow into and out of the peritoneal cavity
20.
[0053] Dual access can be provided, e.g., by a two indwelling
catheters, a dual lumen, indwelling catheter, or two subcutaneous
access devices. Further details of a preferred subcutaneous access
device will be provided later.
[0054] In this arrangement, the set 12 includes a flexible inlet
tube 62 with a connector 64 that connects to the peritoneal cavity
outlet 60. The inlet tube 62 also is also connected to the inlet
port 32 on the patient side 28 of the membrane device 22, to convey
dialysis solution across the patient side 28 of the membrane
26.
[0055] The cycler 14 includes an inlet pump 66. In the illustrated
embodiment, the inlet pump 66 comprises a peristaltic pump. The
pump 66 includes rotating rollers 68 driven by a motor, e.g., a
brushless D.C. motor. The rollers 68, in succession, press against
and pinch the flexible inlet tube 62 against a pump race 70,
thereby urging liquid flow from the peritoneal cavity 20 through
the inlet tube 62 across the patient side 28 of the membrane device
22 in known peristaltic fashion. Of course, other types of
noninvasive pumps can be used, provided that pump speed can be
monitored and controlled.
[0056] The set 12 further includes an outlet tube 72, which is
coupled to the outlet port 34 of the patient side 28 of membrane
device 22. The outlet tube 72 conveys regenerated dialysis solution
from the patient side 28 of the membrane 26. The outlet tube 72
carries a connector 74 that couples to the peritoneal cavity inlet
58, to further convey the regenerated dialysis solution into the
patient's peritoneal cavity 20.
[0057] The cycler 14 also includes two noninvasive pressure sensors
76 and 78. The sensors 76 and 78 monitor fluid pressure,
respectively, in the inlet tube 62 and the outlet tube 72. The
controller 16 analyzes the sensed pressures and regulates the inlet
pump 66 to maintain the pressure in the outlet tube 72 within a
predetermined safe range. The controller 16 also terminates
operation of the inlet pump 66 if sensed pressure in the inlet tube
62 falls outside a predetermined range.
[0058] The cycler 14 further includes a noninvasive fluid intake
valve 80. The controller 16 closes the intake valve 80, to prevent
the supply of dialysis solution to the peritoneal cavity 20, should
a predetermined alarm condition arise.
[0059] (B) Single Access to the Peritoneal Cavity
[0060] In the embodiment shown in FIG. 2, the access device 18
provides a single access through a single indwelling catheter or a
single subcutaneous access device. The single access arrangement
provides semi-continuous flow of dialysis solution into and out of
the peritoneal cavity 20 in a succession of draw modes and return
modes. The quick cycling of draw and return modes provides
virtually the same results as a continuous flow-through procedure,
as just described.
[0061] In this arrangement, the set 12 includes a connector tube 82
with a connector 84 that connects to the single access device 18.
The connector tube 82 includes a y-connector 86, to which the inlet
tube 62 and the outlet tube 72 are connected. The inlet tube 62 is
connected to the inlet port 32 of the membrane device 22. The
outlet tube 72 is coupled to the outlet port 34 of the membrane
device 22.
[0062] In this arrangement, the outlet tube 72 includes an in-line,
non-vented reservoir 88. The reservoir 88 receives regenerated
dialysis solution from the membrane device 22. A sensor 90 monitors
fluid pressure in the reservoir 88, which increases as solution
fills the reservoir 88 and decreases as solution exits the
reservoir 88.
[0063] The cycler 14 includes in the outlet tube 72 the same,
previously described noninvasive fluid intake valve 80. In the
arrangement, the cycler 14 also includes a noninvasive fluid
removal valve 92 in the inlet tube 62.
[0064] The controller 16 toggles the fluid intake valve 80 and the
fluid removal valve 92 between opposing opened and closed states,
to affect successive fluid draw and fluid return modes.
[0065] In the fluid draw mode, the fluid removal valve 92 is opened
and the fluid intake valve 80 is closed. The inlet pump 66 conveys
dialysis solution through the inlet tube 62 from the peritoneal
cavity 20 into the membrane device 22. The outlet tube 72 conveys
regenerated dialysis solution from the membrane device 22 to the
reservoir 88.
[0066] When a predetermined pressure condition exists in the
reservoir 88, as sensed by the senor 90, the controller 16 switches
to the fluid return mode. The inlet pump 66 is stopped. The fluid
intake valve 80 is opened, and the fluid removal valve 92 is
closed. Regenerated dialysis solution flows by pressure from the
reservoir 88 through the outlet tube 72 and into the peritoneal
cavity 20. The return mode terminates when the pressure condition
in the reservoir 88, as sensed by the sensor 90, drops below a
predetermined threshold.
[0067] The controller 16 then switches to another fluid draw mode.
The controller 16 cycles between successive fluid draw and return
modes until the desired objectives of a given therapy session are
met.
[0068] (C) Subcutaneous Access Device
[0069] The system 10 can include one or more subcutaneous access
devices 94, which are specially designed to accommodate high flow
and frequent cannulation. A dual access arrangement requires two
devices 94, whereas a single access arrangement requires but a
single device 94.
[0070] In the dual access arrangement, the connectors 64 and 74 of
the inlet tube 62 and the outlet tube 72 comprise inlet and outlet
cannulas. The cannulas are greater than about 18 gauge, and thereby
capable of sustaining high flow rates to and from the patient's
peritoneal cavity 20. In a single access arrangement, the connector
84 of the connector tube 82 comprises a single cannula.
[0071] The cannula connectors, in turn, are inserted into the
access devices 94. Each device 94 is implanted subcutaneously for
repeated access by the cannula, which is passed into the device 94
percutaneously through the skin.
[0072] The access device 94 can be constructed in various ways. In
the illustrated embodiment (see FIGS. 3 and 4), the device 94 is
generally constructed in the manner disclosed in pending U.S.
patent application Ser. No. 08/724,948, filed Nov. 20, 1996, and
entitled "Subcutaneously Implanted Cannula and Method for Arterial
Access."
[0073] As shown in FIGS. 3 and 4, the device 94 includes a housing
210 carrying a valve assembly 212. The valve assembly 212 comprises
fixed valve member 214 and a shuttle valve member 216.
[0074] The shuttle valve member 216 is movable relative to the
fixed valve member 214 between opened and closed positions. In the
opened position (shown in FIG. 4), the shuttle valve member 216 is
spaced away from the fixed valve member 214, forming a valve
passage 218 between them. In the closed position (shown in FIG. 3),
the shuttle valve member 216 contacts or is in a close adjacent
relationship with the fixed valve member 214, which closes the
valve passage 218. A spring 220 normally biases the shuttle valve
member 216 toward the closed position, shown in FIG. 3.
[0075] The device 94 also includes an access passage 222. The
access passage 222 opens into the interior of the housing 210
through a port 224. The access passage 222 generally extends
perpendicular to the valve passage 218.
[0076] A flexible tube 226 is secured to the access passage 222
inside the housing 210. The tube 226 extends from the access
passage 222 and bends to pass through the valve passage 218. The
tube 226 extends beyond the housing 210 and, when implanted with
the device 94, communicates with the peritoneal cavity 20.
[0077] As FIG. 3 shows, the normally closed position of the valve
assembly 212 pinches the tube 226 between the fixed and movable
valve members 214 and 216, thereby blocking fluid flow through the
tube 226.
[0078] An array of balls 228 rest in a circular channel 230 formed
in the access passage 222 near the access port 224. The circular
channel 230 allows movement of the balls 228 along a formed cam
surface 232 radially of and axially along the access passage 222.
Carried with the circular channel 230, the balls 228 rest against
the shuttle valve member 216.
[0079] The spring 220, which biases the shuttle valve member 216
toward the closed position, also normally urges the balls 228 along
the cam surface 232 out into mutually facing contact within the
access passage 222 near the access port 224. The surface contact of
the balls 228 in this position occurs generally along the center
line of the access passage 222 and port 224.
[0080] A cannula connector C, when passed through the access port
224 and toward the access passage 222, breaks the surface contact
between the balls 228. Continued passage of the cannula connector C
between the separated balls 228 and into the access passage 222
causes the balls to move along the cam surface 232 outward of and
axially along the passage 222 away from the access port 224.
Movement of the balls 228 in this path presses against the shuttle
valve member 216.
[0081] The cannula connector C transmits through the balls 228 a
counter force to the biasing spring 220, which overcomes the spring
bias. As a result, the shuttle valve member 216 is moved away from
the fixed valve member 214, opening the valve passage 218, as FIG.
4 shows. The tube 226, no longer pinched, opens. Fluid flow through
the cannula connector C is directed through the tube 226 to and
from the peritoneal cavity 20.
[0082] Movement of the cannula connector C out of the access
passage 222 relieves the counter force against the balls 228. With
the cannula connector C free of the balls 228, the now unopposed
biasing force of the spring 220 returns the balls 228 along the cam
surface 232 axially toward the access port 224 and radially back
into the access passage 222. At the same time, the shuttle valve
member 216 is urged toward the closed position, closing the tube
226.
[0083] III. Supply of Regeneration Solution
[0084] (A) Batch Process
[0085] The fluid source 40 can provide regeneration solution in a
batch process. In this arrangement (see FIG. 5), the fluid source
40 includes a flexible or rigid source container 96. The source
container 96 contains an aliquot of purified water from the water
treatment module 42 or another source. The aliquot is sufficient to
supply regeneration solution for an entire therapy session.
[0086] Appropriate electrolytes are added to the purified water in
the source container 96. This combination forms the regeneration
solution. The appropriate electrolytes can be bicarbonate buffer
based or lactate buffer based.
[0087] In one embodiment, the appropriate concentration of
electrolytes are enclosed within the source container 96 in a
smaller bag 98. The bag 98 is made of semi-permeable material. When
purified water is introduced into the source container 96, the
electrolytes diffuse through the smaller bag 98 into the water,
making a homogeneous solution. In another embodiment, the
concentrated electrolytes are introduced in powdered or liquid form
to the purified water in the source container 96.
[0088] The regeneration fluid module 44 draws solution from the
source container 96. The module 44 verifies the contents of the
solution for safety and heats the solution to body temperature. The
module 44 then circulates the regeneration solution to the
regeneration side 30 of the membrane device 22, through an inlet
line 114 to the port 36, using a pump 100.
[0089] If desired, the regeneration solution can be passed through
a sterilizing filter 102 prior to entering the regeneration side 30
of the membrane device 22.
[0090] A fluid return line 104 communicating with the outlet port
38 on the regeneration side 30 of the membrane device 22 can
communicate, via the waste module 46, directly with the drain 56.
Alternatively, the fluid return line 104 can be connected to a
waste bag 106, which can itself comprise the source container from
the previous treatment session.
[0091] Still alternatively, the fluid return line 104 can be
connected to the source container 96, forming a re-circulation loop
128. The returning used fluid can be separated from the fresh fluid
in the source container 96 by a temperature boundary layer, or by a
membrane in the source container 96.
[0092] (B) Continuous Flow Process
[0093] The fluid source 40 can also provide regeneration solution
in a continuous flow process. In this arrangement (see FIG. 6), the
water treatment module 42 supplies purified water to the
regeneration solution module 44 on a continuous or on-demand
basis.
[0094] In this arrangement, the regeneration solution module 44
dispenses the appropriate concentrated electrolyte solution from a
source 130 to the purified water to make regeneration solution. As
before stated, the appropriate electrolytes can be bicarbonate
buffer based or lactate buffer based.
[0095] The regeneration solution module 44 verifies the content of
the solution for safety and heats the solution to body temperature.
The regeneration solution module 44 supplies the solution
continuously through the regeneration side 30 of the membrane
device 22, through the inlet line 114 to the inlet port 36, using
the pump 100. As before stated, the regeneration solution module 44
can pass the solution through the sterilizing filter 102 prior to
entering the regeneration side 30 of the membrane device 22.
[0096] In this arrangement, as in the batch arrangement, the fluid
return line 104, coupled to the outlet port 38 of the regeneration
side 30 of the membrane device 22, can be connected to a waste
container 106 or directly to a drain 56 through the waste module
46.
[0097] IV. Fluid Balancing and Removal
[0098] During peritoneal dialysis, it is desirable to maintain, at
least partially, a normal physiologic fluid and electrolytic
balance in the patient. Usually, an ultrafiltration function is
also performed during peritoneal dialysis, by which the overall
fluid level of the individual is decreased.
[0099] For these purposes, the cycler 14 can include a fluid
balancing module 108 (see FIG. 7). In the illustrated embodiment,
the fluid balancing module 108 includes non-invasive fluid flow
rate sensing devices 110 and 112 in the inlet line 114 and the
return line 104 of the regeneration side 30 of the membrane device
22.
[0100] The fluid balancing module 108 also includes a flow
restrictor 116 located in the return line 104. The flow restrictor
116 comprising e.g., a stepper-driven pressure clamp, which pinches
the outlet line 104 to control its flow resistance.
[0101] The controller 16 monitors the flow rates sensed by the
sensing devices 110 and 112. The controller 16 operates the pump
100 and/or the flow restrictor 116 to maintain a zero differential
in flow rates at the inlet and outlet of the regeneration side 30
of the membrane device 22. In this way, fluid balance is maintained
as the dialysis solution is regenerated.
[0102] Other forms of fluid balancing can be used. For example, an
outlet pump can be placed in the return line 104, which can be
operated in tandem with the inlet pump 100 to achieve fluid
balance, without use of in-line pressure sensing. Other flow
control devices in the inlet line 114 and return line 104 can be
used to achieve a fluid balance between fluid entering and leaving
the regeneration side 30 of the membrane device.
[0103] There are alternative ways to achieve fluid balancing in a
continuous flow arrangement, like that shown in FIG. 7. For
example, an outlet pump can be placed in the return line 104, which
can be operated in tandem with the inlet pump 100 to achieve fluid
balance, without use of in-line pressure sensing. Other flow
control devices in the inlet line 114 and return line 104 can be
used to achieve a fluid balance between fluid entering and leaving
the regeneration side 30 of the membrane device 24.
[0104] Fluid balancing can also be achieved in a batch flow
arrangement, like that shown in FIG. 5. For example, a pump may be
placed in-line in the re-circulation loop 128. The pump is operated
in tandem with the pump 100 to achieve fluid balance in the source
container 98. Alternatively, without a re-circulation loop 128, a
pump can be placed in-line in the return line 104 in the same
manner shown in FIG. 7.
[0105] To provide an ultrafiltration function, the cycler 14 can
also include a fluid removal module 118 (see FIG. 7). In the
illustrated embodiment, the fluid removal module 118 includes a
fluid removal line 120 and an in-line pump 122 upstream of the flow
rate sensor 112 in the outlet line 104. The pump 122 draws
additional fluid across the membrane 26 from the dialysis solution,
thereby reducing the overall fluid level of the patient.
[0106] In the illustrated embodiment, the fluid removal module 118
includes means 124 for monitoring the volume of excess fluid
removed. The means 124 can provide a fixed volume measurement
chamber, a valve and timing device, or a container with a weight
sensing device.
[0107] A comparable ultrafiltration function can likewise be
achieved in the same manner in the batch flow arrangement shown in
FIG. 5.
[0108] V. Reuse
[0109] (A) Reusing the Regeneration Solution Paths
[0110] As before described, the portions of the set 12, through
which peritoneal dialysis solution flows from and to the patient's
peritoneal cavity 20, can be removed from the cycler 14 and
disposed of following each treatment. In this arrangement, the
tubes through which the regeneration solution flows during the
procedure can also be disposed of after treatment.
[0111] Alternatively, the fluid source 40 and associated tubes
coupled to it can be cleaned and disinfected following each
treatment for reuse. In one embodiment, the cleaning and
disinfection can be accomplished by flowing heated water, e.g., at
80.degree. C., for, e.g., 1 hour through the fluid source 40 and
associated tubes. In another embodiment, the cleaning and
disinfection can be accomplished by adding chemicals to water
conducted through the fluid source 40 and associated tubes,
followed by a water rinse and disinfectant and residual
testing.
[0112] (B) Reusing the Patient Side Solution Paths
[0113] In an alternative embodiment, the portions of the set 12
through which peritoneal dialysis solution flows from and to the
patient's peritoneal cavity 20 can themselves be cleaned and
disinfected for reuse, along with or independent of the fluid
source 40 and associated tubes coupled to it.
[0114] In one embodiment, the cleaning and disinfection can be
accomplished by connecting the patient connectors 74 and 84
together and circulating hot water (e.g., 80.degree. C.) for, e.g.,
1 hour. The remaining electrolytes in the patient side 28 of the
fluid pathway will cross the membrane 26 into the water on the
regeneration side 30. Circulating hot water through the fluid
source 40 and associated tubes on the regeneration side 30 will
bring the entire set to a cleaning and disinfecting temperature.
After cooling, the regeneration solution side is flushed to remove
pyrogenic material. The patient side 28 is likewise flushed with
fresh, bagged sterile peritoneal dialysis solution to remove
pyrogenic material and to make ready for the next treatment.
[0115] In one embodiment, the membrane device 22 in the patient
side 28 and the filter 102 in the regeneration side 30 are each
pressure tested to determine proper function following heat
disinfection.
[0116] As an alternative embodiment, the tubing serving the patient
side 28 of the membrane device 22 can be removed and disposed of
following the cleaning and disinfection process, and replaced with
new components.
[0117] In an alternative embodiment, a high level disinfectant
comprising chemical additives can be circulated through the tubing
serving the membrane device 22 or fluid source 40. The disinfectant
can be contained in a disinfection container source 132 coupled to
the regeneration module 126 (see FIG. 7). The disinfectant in the
source 132 is mixed or proportioned into the solution as it is
conveyed from the regeneration module 126. During this time, the
patient connectors 74 and 84 can be inserted into a shunt container
126, to dispense the disinfectant through the patient side 28 of
the membrane device 22 and associated tubes.
[0118] The fluid source 40 and associated tubing is disinfected and
then rinsed out by purified water, and tested for disinfectant
residue. The patient side 28 tubes are flushed are flushed with
new, bagged sterile dialysis solution to flush out pyrogenic
material and tested for removal of the chemical agents, and to make
the system 10 ready for the next treatment.
[0119] Various features of the invention are set forth in the
following claims.
* * * * *