Safety vent structure for extracorporeal circuit

• US 7,938,967 B2
• Filed: 09/18/2008
• Issued: 05/10/2011
• Est. Priority Date: 09/19/2007
• Status: Active Grant

• Current Assignee: Fresenius Medical Care Holdings Incorporated (Fresenius Medical Care AG)
• Original Assignee: Fresenius Medical Care Holdings Incorporated (Fresenius Medical Care AG)
• Inventors: Kotsos, Michael Emmanuel, Weaver, Colin, Crnkovich, Martin Joseph, Jensen, Melvin D., Folden, Thomas Irvin
• Primary Examiner(s): Menon; Krishnan S
• Assistant Examiner(s): Gionta; Allison
• Application Number:
  US12/233,111
• Publication Number:
  US 20090071911A1
• Time in Patent Office: 964 Days
• Field of Search: 210/645, 210/646, 210/323.1, 604/321, 604/405
• US Class Current: 210/646
• CPC Class Codes: A61M 1/36222 Details related to the interface between cassette and machine
• CPC Class Codes: A61M 1/362261 at least one cassette surface or portion thereof being flexible, e.g. the cassette having a rigid base portion with preformed channels and being covered with a foil
• CPC Class Codes: A61M 1/362262 Details of incorporated reservoirs
• CPC Class Codes: A61M 1/3627 Degassing devices; Buffer reservoirs; Drip chambers; Blood filters
• CPC Class Codes: A61M 1/3639 Blood pressure control, pressure transducers specially adapted therefor
• CPC Class Codes: A61M 1/3641 Pressure isolators
• CPC Class Codes: A61M 1/3643 Priming, rinsing before or after use
• CPC Class Codes: A61M 1/3644 Mode of operation
• CPC Class Codes: A61M 2205/123 with incorporated reservoirs
• CPC Class Codes: A61M 2205/705 Testing of filters for leaks blood in dialysate A61M1/1692
• CPC Class Codes: A61M 2205/7527 liquophilic, hydrophilic
• CPC Class Codes: A61M 2205/7536 allowing gas passage, but preventing liquid passage, e.g. liquophobic, hydrophobic, water-repellent membranes
• CPC Class Codes: A61M 2205/7563 with means preventing clogging of filters

Abstract

A vent assembly is described for use in an extracorporeal fluid unit. A vent structure adjacent to a micro-porous membrane forms the assembly. The vent structure is porous, but expands when the vent structure becomes wet, thereby closing off the pores and inhibiting (e.g., preventing) fluid from flowing through the vent structure. The vent structure also protects the membrane from becoming wet, such as from condensation.

Claims

1. An extracorporeal medical fluid circuit component, comprising:

a vent assembly comprising;

a micro-porous membrane; and

a vent structure adjacent to the micro-porous membrane, the vent structure comprising;

a first porous layer; and

a second porous layer comprising porous material capable of swelling when moistened,

wherein the first porous layer is disposed between the micro-porous membrane and the second porous layer and the first porous layer is less responsive to the presence of moisture than the second porous layer, and

wherein the component is capable of being used in an extracorporeal medical fluid circuit.

2. The component of claim 1, wherein the vent structure has an average pore size of about 15 microns to about 45 microns.

3. The component of claim 1, wherein the vent structure includes polyethylene, polypropylene or polystyrene.

4. The component of claim 1, wherein the vent structure includes carboxymethylcellulose.

5. The component of claim 1, wherein the vent structure includes a blend of polyethylene and carboxymethylcellulose.

6. The component of claim 1, wherein the vent structure has a thickness greater than a thickness of the micro-porous membrane.

7. The component of claim 1, wherein the micro-porous membrane has an average pore size of about 0.05 microns to about 0.45 microns.

8. The component of claim 1, wherein the micro-porous membrane has an average pore size of about 0.2 microns.

9. The component of claim 1, wherein the micro-porous membrane is held by a ring and the assembly further comprises an insert configured to hold the micro-porous filter adjacent to the vent structure.

10. The component of claim 1, further comprising a ring into which the micro-porous membrane is press-fit, wherein the ring surrounds the vent structure and retains the vent structure adjacent to the micro-porous membrane.

11. The component of claim 1, wherein the first porous layer comprises a porous material capable of swelling when moistened, and wherein the second porous layer has a greater propensity to swell in the presence of moisture than the first porous layer.

12. The component of claim 1, wherein the first porous layer has an average pore size of about 5 microns to about 45 microns.

13. The component of claim 1, wherein the first porous layer has an average pore size of about 10 microns.

14. The component of claim 1, wherein the second porous layer has an average pore size of about 15 to about 45 microns.

15. The component of claim 1, wherein the second porous layer has an average pore size of about 30 microns.

16. The component of claim 1, wherein the second porous layer has an average pore size that is greater than an average pore size of the first porous layer.

17. The component of claim 1, wherein the second porous layer comprises about 5% to about 50% by weight carboxymethylcellulose.

18. The component of claim 1, wherein the first porous layer comprises about 0% to about 10% carboxymethylcellulose.

19. The component of claim 1, wherein the first porous layer comprises less than 5% carboxymethylcellulose.

20. The component of claim 1, wherein the component is configured for use in an air release chamber.

21. The component of claim 1, wherein the component is capable of being used in a blood circuit.

22. The component of claim 21, wherein the blood circuit is capable of being used with a dialysis machine.

23. A dialysis system, comprising:

a machine body;

a pump on the machine body;

a fluid circuitry connected to the pump, wherein the pump is configured to push fluid through the circuitry;

a vent assembly in fluid communication with the fluid circuitry, the vent assembly comprising;

a micro-porous membrane; and

a vent structure adjacent to the micro-porous membrane, the vent structure comprising;

a first porous layer; and

a second porous layer comprising porous material capable of swelling when moistened,

wherein the first porous layer is disposed between the micro-porous membrane and the second porous layer and the first porous layer is less responsive to the presence of moisture than the second porous layer.

24. The dialysis system of claim 23, further comprising;

a chamber in fluid communication with the circuitry adjacent to the machine body, the chamber comprising;

a fluid entry port, and

a fluid exit port,

wherein the circuitry is configured to allow liquid to pass through the chamber from the entry port to the exit port so as to fill the chamber with the liquid, and

wherein the vent assembly is arranged to allow gas to exit the chamber through the vent assembly as the liquid passes through the chamber.