Fluid separation devices, systems and methods

• US 8,496,606 B2
• Filed: 02/04/2009
• Issued: 07/30/2013
• Est. Priority Date: 02/04/2008
• Status: Active Grant

• Current Assignee: Trustees Of Columbia University In The City Of New York (Columbia University)
• Original Assignee: Trustees Of Columbia University In The City Of New York (Columbia University)
• Inventors: Leonard, Edward F., Reich, Ilan K., Cortell, Stanley
• Primary Examiner(s): MARCETICH, ADAM M
• Application Number:
  US12/866,017
• Publication Number:
  US 20110105982A1
• Time in Patent Office: 1,637 Days
• Field of Search: 604/4.01, 604/5.01, 604/5.04, 604/6.01, 604/6.04, 604/6.09, 604/6.11
• US Class Current: 604/6.01
• CPC Class Codes: A61M 1/14 Dialysis systems; Artificial kidneys; Blood oxygenators semi-permeable membranes characterised by the material, manufacturing processes therefor B01D71/00 ; Reciprocating systems for treatment of body fluids, e.g. single needle systems for hemofiltration or pheresis
• CPC Class Codes: A61M 1/3482 by filtrating the filtrate using another cross-flow filter, e.g. a membrane filter
• CPC Class Codes: A61M 2206/11 Laminar flow
• CPC Class Codes: A61P 13/12 of the kidneys

Abstract

A membraneless separation device can be applied to a variety of treatments, such as the ultrafiltration of blood for a patient with end stage renal disease. An ultrafiltration device can include a membraneless separation device, which separates an incoming blood flow into a substantially cytoplasmic body-free plasma flow and remaining fraction, and a dialysate-free second stage, which selectively removes excess fluid, toxins and other substances from the plasma flow and returns the processed plasma to the membraneless separation device. A treatment protocol can include ultrafiltering blood of a patient using the ultrafiltration device and performing a secondary treatment on the blood of the patient at a reduced frequency compared to the ultrafiltering. The membraneless separation device can also be applied to treatment, analysis, and/or exchange of plasma from blood, or combined with conventional dialyzers to perform dialysis on a cytoplasmic body-free plasma fraction.

Claims

1. A method for treating chronic renal disease of a patient comprising:

(a) for a duration of at least 4 hours, performing an ultrafiltration process by using a portable treatment device having a membraneless microfluidic channel, said performing including;

(a1) passing blood at a flow rate into the membraneless microfluidic channel having dimensions such that, at the blood flow rate, a fraction depleted of cytoplasmic bodies from the blood is generated;

(a2) removing a portion of the fraction depleted of cytoplasmic bodies from the membraneless microfluidic channel;

(a3) extracting at least water from the removed portion of the fraction depleted of cytoplasmic bodies using a first membrane; and

(a4) returning the removed portion of the fraction depleted of cytoplasmic bodies, minus some water, back to the patient;

an ultrafiltration rate of the ultrafiltration process resulting in a rate of production of ultrafiltrate of less than 0.4 l/hr;

(b) repeating the performing an ultrafiltration process at least daily, the ultrafiltration process requiring no continuous consumption of exogenous fluid; and

(c) at a frequency that is less than daily, using another treatment device to perform a renal replacement therapy in which blood components are exchanged between blood and a sorbent or between blood and a substantial supply of exogenous fluid across a second membrane, the blood contacting the second membrane or the sorbent of the another treatment device;

the repeating either being done on days in which the performing a renal replacement therapy is done or being skipped on the days in which the performing a renal replacement therapy is done.

2. The method of claim 1, wherein the removing a portion of the fraction depleted of cytoplasmic bodies includes blocking the exit of cytoplasmic bodies from the membraneless microfluidic channel by passing the fraction depleted of cytoplasmic bodies through a wall filter having an array of holes whose sizes are less than 1000 nm, the wall filter forming a part of a wall of the membraneless microfluidic channel.

3. The method of claim 1, wherein the removing a portion of the fraction depleted of cytoplasmic bodies includes blocking the exit of cytoplasmic bodies from the membraneless microfluidic channel by passing the fraction depleted of cytoplasmic bodies through a wall filter having an array of holes whose sizes are between 600 and 1000 nm, the wall filter forming a part of a wall of the membraneless microfluidic channel and forming a continuous unobstructed and smooth surface with the wall of the membraneless microfluidic channel.

4. The method of claim 1, wherein the blood flow rate is at least 0.5 ml/second and less than 5 ml/sec.

5. The method of claim 1, wherein the ultrafiltration process includes positioning the portable device, including the membraneless microfluidic channel, proximate the patient such that blood volume outside the patient'"'"'s body is minimized by minimizing a volume of blood channels.

6. The method of claim 1, wherein the renal replacement therapy includes at least one of hemofiltration, hemodialysis, and hemodiafiltration.

7. The method of claim 1, wherein the renal replacement therapy includes sorption-based dialysis.

8. The method of claim 1, wherein the renal replacement therapy includes dialysis in which blood and a supply of dialysate of at least 10 L are passed across opposite sides of a membrane at least to clear uremic toxins from the blood.

9. The method of claim 1, wherein the ultrafiltration process includes passing the fraction depleted of cytoplasmic bodies across a sorbent configured to remove at least urea therefrom.

10. The method of claim 1, further comprising, prior to the performing an ultrafiltration process, priming the membraneless microfluidic channel and wetting the first membrane of the portable treatment device.

11. The method of claim 1, wherein:

the portable treatment device comprises a detector that monitors the blood flow or the removed portion of the fraction depleted of cytoplasmic bodies; and

said performing an ultrafiltration process is performed responsively to a signal from said detector.

12. The method of claim 1, further comprising, periodically reversing flow through the wall filter in the membraneless microfluidic channel so as to flush a surface of the wall filter.

13. The method of claim 1, wherein the portable treatment device comprises a waste receptacle that receives the at least water extracted from the removed portion of the fraction depleted of cytoplasmic bodies.

14. The method of claim 1, wherein the portable treatment device is configured to perform a treatment without use of exogenous fluids, and the another treatment device is a non-portable device configured to perform a treatment using exogenous fluids.