Lymph filtration system

• US 4,411,792 A
• Filed: 08/10/1981
• Issued: 10/25/1983
• Est. Priority Date: 08/10/1981
• Status: Expired due to Fees

• Current Assignee: Automedix Sciences, Inc. (ICF Corp.)
• Original Assignee: Trimedyne Incorporated (InnovaQuartz, LLC)
• Inventors: Babb, Albert L.
• Primary Examiner(s): Spear, Jr., Frank A.
• Application Number:
  US06/291,175
• Time in Patent Office: 806 Days
• Field of Search: 128/214 R, 128/1 R, 210/195.2, 210/456, 210/411, 210/412, 210/433.2, 210/927, 210/651, 604/5, 604/30
• US Class Current: 210/651
• CPC Class Codes: A61M 1/3496 Plasmapheresis; Leucopheresis; Lymphopheresis A61M1/3472 takes precedence
• CPC Class Codes: A61M 1/3603 in the same direction
• CPC Class Codes: A61M 2202/0035 fluid leaving the cross-flow filter without having passed through the filtering element
• CPC Class Codes: A61M 2202/0405 Lymph
• CPC Class Codes: A61M 2202/0407 Lymphocytes
• CPC Class Codes: A61M 2205/7554 with means for unclogging or regenerating filters
• CPC Class Codes: A61M 2206/12 the flow being spirally in a plane, e.g. against a plane side of a membrane filter element
• CPC Class Codes: A61M 2230/005 Parameter used as control input for the apparatus
• CPC Class Codes: B01D 63/087 Single membrane modules

Abstract

A lymphapheresis or lymph filtration system is disclosed for removing lymph from a patient, separating the lymph into a liquid fraction and a cellular component fraction and returning the liquid fraction to the patient. The system includes an input pump to pump lymph from the patient into a filtration cell having a membrane which filters the lymph into fractions. The liquid fraction is removed from the cell by a reversible pump and is returned to the patient. As the membrane becomes plugged the reversible pump is reversed to backflush the membrane to return it to a high filtration rate. The cellular component fraction which includes lymphocytes is disposed of.

Claims

1. A lymph filtration system for separating lymph into a liquid fraction and a cellular component fraction, the system comprising:

(a) a filtration cell having an inlet, a cellular component outlet and a filtrate outlet, the filtration cell also having a membrane filter dividing the cell into filtering and filtrate members, the inlet and cellular component outlet in fluid communication with the filtering chamber, the filtrate outlet in fluid communication with the filtrate chamber;

(b) an input pumping means for delivering lymph to the inlet of the filtration cell;

(c) an inlet check valve between a patient and the input pumping means;

(d) a reversible filtrate pumping means in fluid communication with the filtrate outlet for pumping fluid to and from the filtrate chamber, the filtrate pumping means when in an operating mode to pump liquid fraction from the filtrate chamber, and when in a backflush mode, to pump a fluid into the filtrate chamber to produce a positive transmembrane pressure from the filtrate chamber to the filtering chamber to backflush the membrane filter; and

(e) control means for controlling the operation of the filtrate pumping means.

2. The lymph filtration system of claim 1 wherein the membrane filter has an effective pore size of about 0.1 to about 1.0 microns.

3. The lymph filtration system of claim 1 wherein the filtering chamber is further defined by a spiral flow path between the inlet and the cellular component outlet, the spiral flow path being substantially planar with the membrane.

4. The lymph filtration system of claim 1 wherein the filtrate chamber defines a series of concentric grooves interconnected by a slot, the grooves being generally coplanar with the membrane and in fluid communication with the filtrate outlet.

5. The lymph filtration system of claim 1 including a recirculation loop in fluid communication between the cellular component outlet and the inlet of the filtration cell, the recirculation loop having a recirculation pumping means for pumping fluid from the cellular component outlet to the inlet to increase fluid flow through the filtering chamber.

6. The lymph filtration system of claim 1 including a hydraulic sensing means operably associated with the filtration cell for providing information to the control means.

7. A lymph filtration system for separating lymph into a liquid fraction and a cellular component fraction, the system comprising:

(a) a filtration cell having an inlet, a cellular component outlet and a filtrate outlet, the filtration cell also having a membrane filter dividing the cell into filtering and filtrate chambers, the inlet and cellular component outlet in fluid communication with the filtering chamber, the filtrate outlet in fluid communication with the filtrate chamber;

(b) an input pumping means for delivering lymph to the inlet of the filtration cell;

(c) a reversible filtrate pumping means in fluid communication with the filtrate outlet for pumping fluid to and from the filtrate chamber, the filtrate pumping means when in an operating mode to pump liquid fraction from the filtrate chamber, and when in a backflush mode, to pump a fluid into the filtrate chamber to produce a positive transmembrane pressure from the filtrate chamber to the filtering chamber to backflush the membrane filter;

(d) control means for controlling the operation of the filtrate pumping means;

(e) a reservoir in fluid communication between the filtrate pumping means and a patient; and

(f) an outlet check valve between the reservoir and the patient;

the filtrate pumping means, when in the backflush mode, pumping liquid fraction from the reservoir into the filtrate chamber.

8. A lymph filtration system for separating lymph into a liquid fraction and a cellular component fraction, the system comprising:

(a) a filtration cell having an inlet, a cellular component outlet and a filtrate outlet, the filtration cell also having a membrane filter dividing the cell into filtering and filtrate chambers, the inlet and cellular component outlet in fluid communication with the filtering chamber, the filtrate outlet in fluid communication with the filtrate chamber;

(b) an input pumping means for delivering lymph to the inlet of the filtration cell;

(c) a reversible filtrate pumping means in fluid communication with the filtrate outlet for pumping fluid to and from the filtrate chamber, the filtrate pumping means when in an operating mode to pump liquid fraction from the filtrate chamber, and when in a backflush mode, to pump a fluid into the filtrate chamber to produce a positive transmembrane pressure from the filtrate chamber to the filtering chamber to backflush the membrane filter;

(d) control means for controlling the operation of the filtrate pumping means;

(e) an outlet check valve between the filtrate pumping means and the patient;

(f) a backflush fluid source in fluid communication with the filtrate pumping means between the filtrate pumping means and the outlet check valve; and

(g) a backflush check valve between the backflush fluid source and the filtrate pumping means such that when the filtrate pumping means is in the operating mode, liquid fraction is pumped from the filtrate chamber to the patient and when the filtrate pumping means is in the backflush mode, backflushing fluid is pumped from the backflush fluid source into the filtrate chamber.

9. A lymph filtration system for separating lymph into a liquid fraction and a cellular component fraction, the system comprising:

(a) a filtration cell having an inlet, a cellular component outlet and a filtrate outlet, the filtration cell also having a membrane filter dividing the cell into a filtering chamber and a filtrate chamber, the inlet and cellular component outlet in fluid communication with the filtering chamber and the filtrate outlet in fluid communication with the filtrate chamber, the filtrate chamber defining a spiral flow path between the inlet and the cellular component outlet, the spiral flow path being substantially coplanar with the membrane filter;

(b) an input pumping means for pumping lymph from a patient to the inlet of the filtration cell;

(c) an inlet check valve between the patient and the input pumping means;

(d) a hydraulic sensing means operably associated with the filtrate outlet;

(e) a reversible filtrate pumping means in fluid communication with the filtrate outlet for pumping fluid to and from the filtrate chamber, the filtrate pumping means when in the operating mode to pump liquid fraction from the filtrate chamber to the patient, and when in a backflush mode, to pump fluid into the filtrate chamber to produce a positive transmembrane pressure from the filtrate chamber to the filtering chamber to backflush the membrane filter;

(f) a control means operably associated with the hydraulic sensor for regulating the outlet pumping means;

and

(g) a reservoir in fluid communication with the filtrate pumping means.

11. The lymph filtration system of claim 9 including a recirculation loop in fluid communication between the cellular component outlet and the inlet of the filtration cell, the recirculation loop having a recirculation pumping means for pumping fluid from the cellular component outlet to the inlet to increase fluid flow through the filtering chamber.

12. The lymph filtration system of claim 9 wherein the filtering chamber has a height, measured perpendicular to the membrane filter, from about 0.1 millimeters to about 1.0 millimeters.

13. The lymph filtration system of claim 9 wherein the reservoir is a backflush fluid source having a backflush check valve and including an outlet check valve between the filtrate pumping means and patient such that when the filtrate pumping means is in the operating mode, liquid fraction is pumped from the filtrate chamber to the patient and when in the backflush mode, backflush fluid is pumped from the reservoir into the filtrate chamber.

14. The lymph filtration system of claim 9 wherein the backflush fluid is sterile saline solution.

15. The lymph filtration system of claim 9 wherein the transmembrane pressure from the filtering to filtrate chamber in the operating mode is from about 100 mmHg to about 200 mmHg.

16. The lymph filtration system of claim 9 wherein the transmembrane pressure from the filtrate to the filtering chamber is the backflush mode is from about 150 mmHg to about 350 mmHg.

17. The lymph filtration system of claim 9 wherein the filtrate pumping means is a constant volume pump.

18. The lymph filtration system of claim 9 wherein the lymph passes over the membrane filter with a shear rate of about 500 to about 2500 sec-¹.

10. The lymph filtration system of 9 wherein the membrane filter has an effective pore size from about 0.1 to about 1.0 microns.

19. A lymph filtration system for removing lymph from a patient, separating the lymph into a liquid fraction and a cellular component fraction and returning the liquid fraction to the patient, the system comprising:

(a) a filtration cell having an inlet, a cellular component outlet and a filtrate outlet, the filtration cell also having a membrane filter dividing the cell into a filtering chamber and a filtrate chamber, the inlet and cellular components outlet in fluid communication with the filtering chamber and the filtrate outlet in fluid communication with the filtrate chamber, the filtrate chamber defining a spiral flow path between the inlet and the cellular component outlet, the spiral flow path being substantially coplanar with the membrane filter;

(b) an input pump for pumping lymph from the patient to the inlet of the filtration cell;

(c) an inlet check valve between the patient and the pump.

(d) a hydraulic sensing means operably associated with the filtrate outlet;

(e) a reversible filtrate pump in fluid communication with the filtrate outlet for pumping fluid to and from the filtrate chamber, the filtrate pump when in the operating mode to pump liquid from the filtrate chamber to the patient, and when in a backflush mode, to pump fluid into the filtrate chamber to produce a positive transmembrane pressure from the filtrate chamber to the filtering chamber to backflush the membrane filter;

(f) a control means operably associated with the hydraulic sensor for controlling the outlet pumping means;

(g) a recirculation loop in fluid communication between the cellular component outlet and the inlet of the filtration cell, the recirculation loop having a recirculation pump to pump fluid from the outlet to the inlet to increase fluid flow through the filtering chamber;

(h) an outlet check valve between the filtrate pump and the patient;

(i) a backflush fluid source in fluid communication with the filtrate pump between the filtrate pump and the outlet check valve; and

(j) a backflush check valve between the backflush fluid source and the filtrate pump such that when the filtrate pump is in the operating mode, liquid fraction is pumped from the filtrate chamber to the patient and when the filtrate pump is in the backflush mode, backflushing fluid is pumped from the backflush fluid source into the filtrate chamber.

21. The lymph filtration system of claim 19 wherein the filtrate chamber defines a series of concentric grooves interconnected by a slot, the grooves being generally coplanar with the membrane and in fluid communication with the filtrate outlet.

22. The lymph filtration system of claim 19 wherein the filtering chamber has a height, measured perpendicular to the membrane filter, from about 0.1 millimeters to about 1.0 millimeters.

23. The lymph filtration system of claim 19 wherein the transmembrane pressure from the filtering to filtrate chamber while the filtrate pump is in the operating mode is from about 100 mmHg to about 200 mmHg.

24. The lymph filtration system of claim 19 wherein the transmembrane pressure from the filtrate to the filtering chamber while the filtrate pump is in the backflush mode is from about 150 mmHg to about 350 mmHg.

25. The lymph filtration system of claim 19 wherein the lymph passes over the membrane filter with a shear rate of about 500 to about 2500 sec-¹.

20. The lymph filtration system of 19 wherein the membrane filter has an effective pore size from about 0.1 to about 1.0 microns.

26. A method for separating lymph into a liquid fraction and a cellular component fraction, the method comprising:

(a) passing a stream of lymph over one side of a membrane filter, the stream having a shear rate in excess of 500 sec-¹ ;

(b) introducing a positive transmembrane pressure through the membrane filter;

(c) collecting filtered liquid fraction on the other side of the membrane filter;

(d) periodically introducing a negative transmembrane pressure to backflush the membrane filter; and

(e) discarding the cellular component.

27. The method of claim 26 wherein the stream of lymph is constrained to pass in a spiral flow path over the membrane filter.