Systems and methods for performing blood processing and/or fluid exchange procedures

• US 6,979,309 B2
• Filed: 01/07/2002
• Issued: 12/27/2005
• Est. Priority Date: 02/14/1997
• Status: Expired due to Fees

• Current Assignee: Nxstage Medical Incorporated (Fresenius Medical Care AG)
• Original Assignee: Nxstage Medical Incorporated (Fresenius Medical Care AG)
• Inventors: Treu, Dennis M., White, Steven A., Finch, C. David Jr., Brugger, James M., Burbank, Jeffrey H., Fulkerson, Barry N.
• Primary Examiner(s): Bianco, Patricia
• Application Number:
  US10/041,949
• Publication Number:
  US 20020147423A1
• Time in Patent Office: 1,450 Days
• Field of Search: 604/4.01, 604 501- 504, 604/6.09, 604/6.1, 604/6.11, 604 615- 616, 604403-416, 604 65- 67, 422/44, 422/110, 422105-108, 415/1, 415/2, 415/65, 210645-647, 210650-652, 210/739, 210/741, 210/744, 210/767, 210/790, 210/805, 210 87- 90, 210/97, 210/98, 210/252, 210/85
• US Class Current: 604/6.16
• CPC Class Codes: A61M 1/1611 Weight of the patient
• CPC Class Codes: A61M 1/282 Operational modes
• CPC Class Codes: A61M 1/288 Priming priming in extracorporeal blood circuits A61M1/3643
• CPC Class Codes: A61M 1/34 Filtering material out of the blood by passing it through a membrane, i.e. hemofiltration or diafiltration
• CPC Class Codes: A61M 1/3401 Cassettes therefor
• CPC Class Codes: A61M 1/3403 Regulation parameters
• CPC Class Codes: A61M 1/341 by measuring the filtrate rate or volume
• CPC Class Codes: A61M 1/342 Adding solutions to the blood, e.g. substitution solutions for preventing coagulation A61M1/3672
• CPC Class Codes: A61M 1/3441 Substitution rate control as a function of the ultrafiltration rate
• CPC Class Codes: A61M 1/3444 in which the collected ultra-filtrate expels an equal volume of substitution fluid from a reservoir
• CPC Class Codes: A61M 1/3448 by mechanically linked pumps in both ultra-filtrate and substitution flow line
• CPC Class Codes: A61M 1/361 before treatment
• CPC Class Codes: A61M 1/3612 after treatment
• CPC Class Codes: A61M 1/36222 Details related to the interface between cassette and machine
• CPC Class Codes: A61M 1/36224 with sensing means or components thereof
• CPC Class Codes: A61M 1/36225 with blood pumping means or components thereof
• CPC Class Codes: A61M 1/36226 Constructional details of cassettes, e.g. specific details on material or shape
• CPC Class Codes: A61M 1/362262 Details of incorporated reservoirs
• CPC Class Codes: A61M 1/362265 Details of valves
• CPC Class Codes: A61M 1/3626 Gas bubble detectors
• CPC Class Codes: A61M 1/3639 : Blood pressure control, pressure transducers specially adapted therefor
• CPC Class Codes: A61M 1/3646 : Expelling the residual body fluid after use, e.g. back to the body
• CPC Class Codes: A61M 1/367 : Circuit parts not covered by the preceding subgroups of group A61M1/3621
• CPC Class Codes: A61M 2205/126 : with incorporated membrane filters
• CPC Class Codes: A61M 2205/128 : with incorporated valves
• CPC Class Codes: A61M 2205/15 : Detection of leaks
• CPC Class Codes: A61M 2205/3331 : Pressure; Flow
• CPC Class Codes: A61M 2205/3334 : Measuring or controlling the flow rate
• CPC Class Codes: A61M 2205/3368 : Temperature
• CPC Class Codes: A61M 2205/3375 : Acoustical, e.g. ultrasonic, measuring means
• CPC Class Codes: A61M 2205/35 : Communication
• CPC Class Codes: A61M 2205/505 : Touch-screens; Virtual keyboard or keypads; Virtual buttons; Soft keys; Mouse touches
• CPC Class Codes: A61M 2205/60 : with identification means
• CPC Class Codes: A61M 2205/6018 : providing set-up signals for the apparatus configuration
• CPC Class Codes: A61M 2205/6072 : Bar codes
• CPC Class Codes: A61M 39/0208 : Subcutaneous access sites for injecting or removing fluids transcutaneous access sites A61M39/0247; implantable infusion devices A61M5/14276

Abstract

A flow management system for extracorporeal blood treatment application helps to ensure proper balance of incoming and outgoing fluids by precise balancing of relatively small balance chambers. The invention employs combinations of features that help to ensure accuracy including underfilling of the waste flow side of a fixed volume chamber and mechanical connections to synchronize valves and pumps.

Claims

1. A fluid balancing system comprising:

first and second chambers alternately fed by an incoming fluid that is consumed by a process and an outgoing fluid that is discarded from said process;

said first and second chambers being configured to displace fluid mutually such that as one is filled, fluid is forced out of the other and vice versa;

an incoming fluid supply mechanism that conveys incoming fluid into said first chamber during a first cycle such that said first chamber is entirely filled with said incoming fluid, thereby displacing said outgoing fluid from said second chamber;

an outgoing fluid supply mechanism that conveys outgoing fluid into said second chamber during a second cycle such that said second chamber is only partly filled with said outgoing fluid, thereby displacing an equal volume of said incoming fluid from said first chamber.

2. A system as in claim 1, wherein said outgoing fluid supply includes a positive displacement pump that is controlled such that it displaces, during each of said first and second cycles, no more fluid than required to partially fill a respective one of said first and second chambers.

3. A system as in claim 2, wherein said first and second cycles correspond to respective inlet and outlet valve configurations which control said incoming and outgoing fluid supply mechanisms and said positive displacement pump is mechanically synchronized with a mechanical mechanism that controls said valve configuration.

4. A system as in claim 3 wherein said incoming fluid supply mechanism includes a pump mechanism and a fluid bypass configured to allow said incoming fluid to recirculate once a respective one of said first and second chambers is filled, said first cycle being such that said incoming fluid is supplied at such a volume that it completely fills said respective one of said first and second chambers causing it to recirculate, whereby a complete filling of said respective one of said first and second chambers is ensured.

5. A system as in claim 1, wherein said incoming fluid supply mechanism includes a pump mechanism and a fluid bypass configured to allow said incoming fluid to recirculate once a respective one of said first and second chambers is filled, said first cycle being such that said incoming fluid is supplied at such a volume that it completely fills said respective one of said first and second chambers causing it to recirculate, whereby a complete filling of said respective one of said first and second chambers is ensured.

6. A system as in claim 1, wherein said first and second cycles correspond to respective inlet and outlet valve configurations which control said incoming and outgoing fluid supply mechanisms and said positive displacement pump is mechanically synchronized with a mechanical mechanism that controls said valve configuration.