Surgery – Means for introducing or removing material from body for... – Material introduced into and removed from body through...
Reexamination Certificate
2000-02-23
2001-07-03
Mendez, Manuel (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Material introduced into and removed from body through...
Reexamination Certificate
active
06254567
ABSTRACT:
1. Field of the Invention
The invention relates to systems and methods for performing peritoneal dialysis.
BACKGROUND OF THE INVENTION
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.
Conventional peritoneal dialysis solutions include dextrose in concentrations sufficient to generate the necessary osmotic pressure to remove water from the patient through ultrafiltration.
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.
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.
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.
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
The invention provides systems and methods for conducting peritoneal dialysis.
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.
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.
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.
In one embodiment, the regeneration assembly includes a device to heat the regeneration solution before circulation along the second side of the porous membrane.
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.
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.
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.
In one embodiment, the regeneration assembly includes an ultrafiltration module to selectively transport a preselected greater volume of waste than regenerating agent.
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.
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 d
Brugger James M.
Burbank Jeffrey H.
Treu Dennis M.
Mendez Manuel
NxStage Medical Inc.
Ryan Kromholz & Manion S.C.
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